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Instructors’ Manual for

Air Conditioning A Practical Introduction

third edition

This Instructors’ Manual complements Air

Conditioning, A Practical Introduction, third

edition, with a bank of multiple choice answer

questions. 1300 questions cover the range of

topics in the textbook and more. The objective

of this manual is to provide a teaching, learning

and testing resource. Hyperlinks are given to

all sections.

David V. Chadderton

14th November 2013

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Introduction

Air Conditioning, A Practical Introduction, third edition, Instructors’ Manual complements

the textbook with a bank of multiple choice answer questions. Questions cover the range of

topics in the text book and more. The objective of this manual is to provide a teaching,

learning and testing resource that the author never had, but would have appreciated.

The comprehensive contents list is hyperlinked to all chapters and subject sections to make

navigation and return to the table of contents easy.

The subjects within this manual can be of valuable assistance to instructors of courses

other than within those of building services engineering, architecture, surveying and

construction.

Wherever air conditioning systems, climate variation, low energy uncooled buildings,

cooling load calculation, annual energy, psychrometrics, fan applications, air duct design,

building management systems (BMS), commissioning, maintenance, air duct acoustics, post

occupancy assessment, thermal environment, human comfort, energy economics, ventilation,

assessing a project cost and selling price and the use of units of measurement are studied,

users will find material of benefit.

Instructors can easily edit and adapt the questions provided for their own purposes and

create unique testing assignments.

There are over 1300 questions . These repeat questions in the printed book and add many

multiple choice answer questions. They are collected into subject groups and also into random

subject sections.

Correct responses are in red as the Instructors’ Manual is only provided as downloadable

files to instructors. The user edits the highlighted answers when preparing them for student

use. Question grouping allows rapid access to each topic area. Some questions require more

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knowledge than is provided in the printed book. Users need to draw upon on-site observation

and experience plus further investigation, discussion, questioning and searching the internet.

Multiple choice questions usually have responses with only one correct answer, although

discussion may occur where shades of opinion are not clear-cut for every application. In order

to stimulate users away from only seeking one answer, many questions are provided with

more than one correct response.

Correct answers are only one part of the whole solution; just select from answers provided.

Use these questions for class and individual revision. Even the spurious alternatives

provide a valid means of revising understanding and reinforcement of learning. They all

require mental gymnastics to evaluate them. Groups of questions can be provided to students

for assignments. Test students’ understanding by requiring explanations for why answers are

incorrect.

The author has found that students respond well to competition between groups when led

by the instructor as it adds an element of fun to learning. A class quiz of twenty-five questions

is about right for a one hour session for groups of up to five students each. The quiz leader

fires a question at a named individual, allows no conferring within the group, awarding one

point for the correct response and taking a point away from the group if incorrect, then throws

the question open to anyone to answer for a point.

Alternatively, display a question with optional responses though a data projector for the

class from the files provided. Correct solutions appear on a second slide highlighted in red.

The instructor challenges a group to discuss and agree the correct responses within say thirty

seconds, awarding a point for fully accurate answers.

Sets of questions are suitable for college internal websites where students are allowed

limited time for undertaking tests and assignments. Files of questions may be emailed to

students for response by a specified date and time.

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Some of these multiple choice questions are reproduced in the printed book to stimulate

interest and prepare readers for tests; they appear in the questions bank and in each chapter.

Such duplication from the manual does not create conflict as the textbook and the manual

have different readerships. The instructor is provided with all the available questions in this

manual.

The author expects users to find as much enjoyment and educational benefit in answering

and discussing these questions as he did in producing them. Happy quizzing!

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Contents

1 Uncooled low energy design

Case studies

General knowledge

2 Air conditioning systems

Air filters

Applications

Damper schedule

Heat pumps

Humidifiers

Low cost cooling

Project building

What is air conditioning?

Zones

3 Heating and cooling loads

Admittance values

Air quality

Around the world

Buildings’ responses

Combined heat and power

Combustion

Degree days

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Discounted cash flow, DCF, NPV, IRR

Energy audit

Energy cost

General knowledge

Heat gains

Heat transfer

Humidity

Measuring instruments

Sick building syndrome

Temperature and pressure

Terminology

Thermal comfort

Thermal insulation

U values

Units of measurement

Ventilation

Ventilation heat demand

World energy resources

4 Psychrometric design

Psychrometric chart

5 System design

Air conditioning systems

Air curtains

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Air flow measurement

Air handling units

Chilled beams

Chilled water system

Commissioning

Cooling towers

Design calculation

Duct insulation

Duct noise

Fans

General knowledge

Ground source heat pumps

Health hazards

Heat exchangers

Heat transfer

Hot water heating systems

How systems work

Nuclear power

Observations

Psychrometric chart

Refrigeration

Service duct space

Supply air condition

System applications

System components

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Under floor air distribution

Ventilation strategies

6 Ductwork design

Air flow capacity

Air pressure

Duct pressures

Measurements

Static regain

7 Controls

Actuators

Building management systems

Components

Control mode

Control schematics

Fan control

Refrigeration system control

Wiring diagram

8 Commissioning and maintenance

Commissioning work

Duct leakage

Maintenance manual

Maintenance work

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9 Fans

Commissioning fans

Fan and system operation

Fan control

Fan curves

Fan testing

Fan types

Fans and systems

Opening force

10 Fluid flow

Air ducts

Flow calculation

Gas

Heating systems

Thermal storage

11 Air duct acoustics

Acoustic knowledge

Addition of sounds

Attenuation

Basics

Decibel

Design cases

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Fan sound power

Human ear

Machinery noise

Noise and vibration

Noise rating

Noise rating design

Plant room calculations

Reverberant and direct sound fields

Room absorption

Room sound pressure levels

Sound power and pressure

Sound power level

Structure borne noise

Terminology

What sound does

12 Air conditioning system cost

Project

13 Question bank

Acoustics

Acronyms

Air conditioning

Air quality


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CO2 emissions

Density

Electrical

Fabric energy storage

Fans

General knowledge

Government policies

Heat transfer

Low energy buildings

Lucky dip

Refrigeration systems

Sustainability

Temperature

Thermal comfort

Ventilation

Volume

14 Understanding units

Density

Electrical

Energy

Frequency

General knowledge

Heat transfer

Mathematics

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Pressure

Temperature

Units

Volume

The end

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1 Uncooled low energy design

Case studies

1. What is your opinion of The Shard building( 4–6 London Bridge Street, London, SE1

9SG) at London Bridge station? A one word answer was it? Prefer to pass on to the next

question? Know the answer without calculation? A great deal of work went into it and the

substantial building is expected to stand there for 50 plus years, so we cannot ignore it. In the

context of peak summertime temperature, what would happen on the intermediate 68th floor

viewing deck?

Visit the-shard.com website, also in Wikipedia, and look at the features. Locate the corner

of Borough High Street, St. Thomas Street and Bedale Street in Google Earth and stand there

to view The Shard at a distance. Move around The Shard and its surroundings. View the many

photographs taken and relate the design to its surroundings. Many views show construction

underway.

Each level has floor to ceiling triple glazing with automatic internal blinds. Assume the

glazing to be clear/clear/heat absorbing. There is no point in lowering internal blinds on the

windows of this viewing deck as there would be no view out. The 68th floor dimensions are

approximately 12 m × 12 m × 3 m high. The building faces approximately N, S, E and W.

The inner core comprises lift shafts and various rooms. We will consider this to be a

lightweight construction. Only a few lower floors will have any shading from surrounding

low height buildings.

Copy a workbook file, rename it as shard and enter the data to predict the peak

summertime temperature without any air conditioning. As a simplification, ignore the inner

core walls as they add thermal mass and make the internal conditions worse.

Triple glazing U 3 W/m2 K, Y 3 W/m2 K, f 1.0, lag 0 h, solar correction factor 0.37 and

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alternating solar correction factor 0.35; ceiling U 0 W/m2 K, Y 0.3 W/m2 K, f 0.5, lag 10 h;

floor U 0 W/m2 K, Y 1.5 W/m2 K, f 0.9, lag 10 h. There are no walls, the perimeter is all glass,

there are 20 occupants during 10.00–22.00 h and no lights are switched on.

Answer. The viewing deck is uninhabitable without air conditioning from 06.30 to 20.30 h as

tei remains above 26oC, peaking at 43oC at 15.00 h, as we expected.

2. An outstanding design using natural ventilation with no cooling is the London Olympic

2012 Velodrome in Stratford. (CIBSE Journal, October 2012, Built for Speed, pp. 30–36.)

Locate Quartermile Lane alongside the Velodrome, look around the site and view the many

photographs. Some show construction work underway. Note the extensive low and high level

exterior ventilation louvres and strips of roof lights admitting fully diffused daylight. The

entrance foyers are glazed but fully shaded with large flat verandas. Concourse glazing

provides daylight into the spectator area all around the building. The designer’s intention was

to maintain 28oC d.b. air at track level.

Visit the london2012.com website, look at the features and take the virtual tour of the

Velodrome and watch the construction videos. There are two entrance foyers on the short

sides, one facing approximately south and the other approximately north.

All dimensions are approximations for the purpose of this exercise: floor 100 m × 50 m;

average internal height 12 m; perimeter double glazing, above the track, is 2.5 m high; each

entrance foyer double glazing is 32 m × 3 m; eight double glazed roof lights of 80 m × 1 m.

We will consider this to be a lightweight construction. Copy a workbook file, rename it as

velodrome and enter the data to predict the peak summertime temperature without any air

conditioning. Enter data for the building as if it were rectangular with a flat roof.

Triple glazing U 3 W/m2 K, Y 3 W/m2 K, f 1.0, lag 0 h, solar correction factor 0.6 and

alternating solar correction factor 0.5; wall U 0.3 W/m2 K, Y 0.8 W/m2 K, f 0.6, lag 6 h; roof

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U 0.25 W/m2 K, Y 1.5 W/m2 K, f 0.9, lag 3 h; concrete floor U 0.1 W/m2 K, Y 3 W/m2 K, f

0.7, lag 10 h.

Make sure to correct the cell references for the time lags given. Calculate the peak

summertime environmental temperature for an empty building with no lighting switched on.

Select an assessment for the building leakage rate and test other values. Then save the file as

velodrome2 and add 6000 spectators, 200 track personnel and 356 down lights of 1 kW each

for television use. Consider occupancy time to be 10.00 h to 24.00 h.

Answer. Our assumption of a rectangular building, not the rounded shape, north and south

entrance glazing that is very well shaded from solar gain by verandas, and full occupancy,

have led to our overestimation of the heat gains. We have no published information of the

natural ventilation rate. For leaky standard, empty Velodrome, tei of 28oC is exceeded from

12.00 to 17.00 h but falls away rapidly in the evening, as is expected for the UK. When fully

occupied, 28oC is exceeded from 10.00 to 19.00 h even with 8.3 air changes per hour, and

then falls away. Indoor air temperature could be 1–2oC below environmental, as discussed

earlier. We have predicted a peak tei of 32.4oC when there are 8.3 air changes/h and 42.1oC

when there are 3 air changes/h, meaning a measurable range for tai to be 30–40oC d.b. This

can be considered to be a very satisfactory outcome from such a simplified assessment as the

designers’ published modelling predictions show track air to be 30oC and 36oC around the

spectators and ceiling.

3. Locate the Woodhouse Medical Centre at 5–7 Skelton Lane, Woodhouse, near Sheffield

with Google Earth. Constructed in 1989, it was intended as a low energy green building,

single-storey with brick/block walls and high thermal insulation and natural ventilation

(PROBE 6, Woodhouse Medical Centre, BSJ August 1996). Look around to observe how the

medical centre fits in with nearby architecture consisting of 1–2-storey brick and tile

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traditional and well-established houses and public buildings. It blends very easily with its

semi-rural surroundings. Windows are small, openable and are shaded with eaves. We will

calculate summertime temperature for the front part of the left hand building facing onto

Skelton Lane showing three small windows facing the lane. This square floor plan is 14 m ×

14 m and has 3 m room height. 4 m2 of single glazing face north onto Skelton Lane, 12 m2

face west, none face east. The south end is an attached internal wall. Consider the 6 m2 of

openable single glazed roof lights to be on a horizontal roof. Window U 3 W/m2 K, Y 3 W/m2

K, f 1.0, lag 0 h, solar correction factor 0.76 and alternating solar correction factor 0.5; walls

U 0.4 W/m2 K, Y 3 W/m2 K, f 0.4, lag 10 h, ceiling U 0.3 W/m2 K, Y 0.7 W/m2 K, f 1, lag 10

h; floor U 0.25 W/m2 K, Y 1.5 W/m2 K, f 0.9, lag 10 h; internal wall U 1.5 W/m2 K, Y 5 W/m2

K, f 0.5, lag 10 h. There are 10 occupants during 09.00–20.00 h. Copy a workbook file,

rename it as woodhouse and enter the data to predict the peak summertime temperature.

Answer. Tight air leakage standard selected. The occupants did not make use of the manually

controlled ventilators, windows or openable roof lights; summer overheating led to the

installation of room air conditioners. No air leakage test was conducted. 26oC is exceeded

during working hours of 10.30–19.30 h.

4. What result do you expect from calculation of peak internal summertime temperature in a

UK commercial building that was designed for air conditioning, windows not openable, every

workstation having a computer, shaded glazing to avoid sun glare for all workstations,

artificial lighting continuously on and occupancy around 8 m2 per person?

Answer. Little point in making the calculation. Internal heat gains from people, lighting and

computer systems may exceed heat gains from the external environment. Internal heat gains

are a constant and may exceed heat loss from the building during cold weather. Mechanical

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ventilation and air conditioning is a necessity. No way could any form of uncooled ventilation

system maintain comfort.

5. Locate the Tower of London, central White Tower, with Google Earth. Constructed in

1078, it would have been the epitome of construction design and skill at the time. What sort

of peak summertime temperature might the original residents and guests experience? Look

around to observe how the White Tower fits in within the Tower of London architecture.

Other surrounding buildings did not exist in the present form, so ignore them. Ignore the

dungeons for calculation purposes. Windows are small, probably not openable and have no

shading or eaves. The square floor plan is approximately 20 m × 20 m and a total of 13 m

height. Facades face virtually N, S, E and W. Natural ventilation from doors and chimneys

from open log fireplaces would create a draughty environment. There is around 25 m2 of lead

light single glazing on each façade. Solid stone walls probably 1 m thick or more U 3 W/m2

K, Y 5 W/m2 K, f 0.5, lag 10 h; windows U 6 W/m2 K, Y 6 W/m2 K, f 1.0, lag 0 h, solar

correction factor 0.76 and alternating solar correction factor 0.5; roof heavyweight

construction U 3 W/m2 K, Y 5 W/m2 K, f 0.5, lag 10 h; stone floor U 0.4W/m2 K, Y 4 W/m2

K, f 0.6, lag 10 h. 120 occupants 24 hours a day for staff, soldiers and prisoners. Combustion

of hydrocarbon fuel, wood and candles, for cooking, lighting and water heating, will not be

counted in this calculation. Copy a workbook file, rename it as white tower and enter the data

to predict the peak summertime temperature. Overall time lag for the building would be

measured in days and probably felt cold indoors all summer. Visit a castle or cathedral to

observe internal air conditions in summer, that is, on a warm summer day. Compare what you

calculate with modern buildings known to you.

Answer. Using an average air leakage standard, a consistently warm internal environment

during summer is maintained. Thermal storage time lags are so long, days rather than hours,

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that once warmed, the inside remains warm; rather like in deep caves. On a typical London

summer day, the interior does not overheat and peaks at 26.2oC environmental temperature,

not that the builders would have understood that at all. Note the evenly warm conditions only

ranging between 22.3oC and 26.2oC. We have no reason to think that weather was

significantly different in 1078 to today, apart from being told that today is warmer due to our

use of hydrocarbon fuels. What has modern design learned? Obviously we design and build

much faster in modern times as compared to ancient builders, but our glass-ridden,

lightweight steel and concrete towers are uninhabitable without mechanical cooling and

mechanical ventilation. Have we improved on the ancients’ work? Have a look and visit

buildings of 1000 years of age. All buildings require maintenance or they fall down, so there

is no change there. We might conclude that modern life has been a retrograde step in the

design of buildings and led us to burn more hydrocarbon fuels that emit carbon dioxide into

the atmosphere, which leads to climate change, global warming and a need to reduce our

dependence on such fuels. What do you think?

6. Calculate the peak summertime temperature in a caravan. These are a popular means of

holidaying, preferable to frame tents for keeping rain out and for surviving a camping

experience in muddy fields. Windows are small, openable, no eaves and have interior shading.

A typical floor plan is 6 m × 2 m and 2 m height. A camper selects a southern England costal

site and places the caravan so the long side faces south for the view. There are 2 m2 of

darkened single polycarbonate glazing on each facade U 3 W/m2 K, Y 3 W/m2 K, f 0.5, lag 0

h, solar correction factor 0.2 and alternating solar correction factor 0.2; walls and roof are of

the same construction of galvanised steel frame, aluminium external skin, 50 mm glass fibre

insulation and 5 mm board U 1 W/m2 K, Y 1 W/m2 K, f 1.0, lag 1 h; carpeted, uninsulated

wood floor U 2W/m2 K, Y 2 W/m2 K, f 1, lag 1 h. Two occupants remain in the caravan all

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day, resting. They keep all windows and doors fully open and the ventilation standard is

leaky. Ignore lighting, cooking, refrigerator, TV and hot water heat gains. Compare the living

conditions with those of a brick building. Copy a workbook file, rename it as caravan and

enter the data to predict the peak summertime temperature.

Answer. Notice how the internal environmental temperature tracks the outside air

temperature. With so little thermal lag in the structure of the lightweight caravan and a

necessarily high ventilation rate, internal conditions are outside air plus solar heat gains for

the ventilated box. 26oC environmental temperature is exceeded during 10.00–18.30 h. The

occupants are on holiday, they might switch on a fan to improve air flow and adjust clothing

to be more comfortable. If this was the office or factory of their employment, they would

complain, but here they accept discomfort, and almost certainly choose to sit in the shade

outdoors.

7. Corrugated galvanised, or colour bonded, sheet steel commenced being used as a building

material in the 1840s and remains in extensive use today. It was easily transported to

Australia and the Americas by early traders until local production took over. Some architects

choose to use it as a feature of their designs. Calculate the peak summertime temperature in a

building constructed of a steel frame and uninsulated corrugated steel on a cast concrete floor.

Such buildings are a well-known van factory in Southampton, many industrial buildings and

garden sheds. Single-storey colonial period houses in the 1800s were lined with painted

hessian and later, insulated and lined with plasterboard. Copy a workbook file, rename it as

corrugated iron and enter the data to predict the peak summertime temperature.

Take a floor plan of 15 m × 15 m and 2.8 m height facing N, S, E and W. There are 5 m2 of

clear single glazing on each facade U 6 W/m2 K, Y 6 W/m2 K, f 0.5, lag 0 h, solar correction

factor 0.76 and alternating solar correction factor 0.66; walls and roof are of the same

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construction of galvanised steel frame, single sheet of corrugated galvanised sheet steel U 6

W/m2 K, Y 6 W/m2 K, f 1.0, lag 1 h; concrete floor U 0.4 W/m2 K, Y 2 W/m2 K, f 1, lag 10 h.

There are no permanent occupants, lights and equipment are not operating, doors are closed

and air leakage rate is taken as tight. What happens if the walls and roof are insulated to U 1

W/m2 K and Y 1 W/m2 K? Compare the living conditions with those within other buildings.

Answer. 26oC environmental temperature is exceeded during 09.30–18.45 h with a peak of

32.5oC without insulation. Opening up the doors and windows to maximise outdoor air

ventilation makes little difference. The lack of thermal insulation and storage in the structure

allows indoor temperature to match that outdoors overnight. Insulating the walls and roof

reduces the peak temperature to 29.6oC and maintains a warmer interior overnight. Increasing

the ventilation lowers interior temperatures and makes the building more manageable. The

principle advantage of using corrugated steel is in creating shade; it also heats up rapidly to a

high temperature and convects heat away. In addition, it is a cheap and weatherproof building

material, easily transported and erected. In temperate climates, it needs a lot of added thermal

and sound insulation.

8. Holidaying, or for other reasons living under canvas, is an experience of living outdoors

with minimal shelter that many of us have had. An aluminium frame tent 4 m × 4m and 2 m

high covered in thin waterproofed canvas with a built-in ground sheet, has a south facing front

entrance and window amounting to clear glazing of 4 m2. Window, door, walls and roof all

have U 6 W/m2 K, Y 6 W/m2 K, f 1.0, lag 0 h. Glazing solar correction factor 0.76 and

alternating solar correction factor 0.66; earth floor U 1 W/m2 K, Y 4 W/m2 K, f 0.6, lag 10 h.

There are no occupants for the purpose of this calculation. Calculate summertime temperature

in the tent when the door is closed and outside air is almost still. Comment on the living

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conditions provided. Copy a workbook file, rename it as tent and enter the data to predict the

peak summertime temperature.

Answer. 26oC environmental temperature is exceeded during 09.00–19.00 h with a peak of

34.1oC using a tight leakage standard. Opening up the doors and windows to maximise

outdoor air ventilation makes little difference. The lack of thermal insulation and storage in

the structure allows indoor temperature to match that of outdoors overnight. When we live

outdoors, we accept discomfort as part of the experience and adjust our activities to suit the

conditions. We might complain, but there is no point as being there is our fault. However, we

might appreciate our centrally heated, draught proof, cooled and electrically lit homes and

workplaces more as a result.

9. Many people in the UK live in a traditional unimproved terraced 2–3 bedroom house

having brick cavity walls, suspended timber ground floor and a pitched grey slate roof.

Original houses had no such thing as thermal insulation or draught proofing. Significant

natural ventilation was needed to provide draught for the chimneys and burning black coal.

Locate the corner of Hurst and Hilda Streets, Oldham, Lancashire with Google Earth. Many

of these very small homes have been extended by building a bedroom into the roof space

and/or by building out into the tiny back yard. We will calculate for an unimproved original

design.

Look west to the end of Hilda Street. What do you see? The chimney of a steam boiler

plant that powered the adjoining cotton mill of the 1800s’ industrial revolution. Walk around

the old four-storey industrial building and imagine working there, walking or cycling to work

from the houses in nearby streets. No electricity, piped gas, cars or indoor plumbing for those

occupants. Every room had, still has the facility for, an open coal-burning fireplace and a

closed coal-burning cooking stove in the main living/kitchen room. Larger homes had a coal

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cellar and access manhole in the front footpath for deliveries by manually carried sacks from a

horse-drawn cart. Central heating? No such thing for mill workers. Such houses date back to

the 1850s. Look around to observe nearby architecture consisting of small terraced shops,

two-storey red Lancashire brick and tile traditional houses, modern houses looking the same

as the 1800s’ design, larger houses and public buildings. New industry and housing is

changing the landscape. What is the large green dome seen from the corner of Hurst and Hilda

Streets? A mosque. This shows the changing demographics. Also cars fill any available

parking space. Notice the modern UPVC framed windows, probably double glazed, rather

than the original wood frames. Doors now are also either smart, glazed UPVC or decorative

wood. A permanent air brick below the front window allows through draft for the open coal

fires.

Calculate summertime temperature for an inner terraced house in Hurst Street. Floor plan

is 4.25 m width of house, 9 m length and 2.7 m room height (bricks counted for dimensions).

9 m2 of single glazing face east onto Hurst Street, 10 m2 at the rear elevation face west, none

facing north or south. Window U 5.7 W/m2 K, Y 5.7 W/m2 K, f 1.0, lag 0 h, solar correction

factor 0.76 and alternating solar correction factor 0.5; walls U 1.5 W/m2 K, Y 4.5 W/m2 K, f

0.4, lag 10 h, roof U 2.3 W/m2 K, Y 2 W/m2 K, f 1, lag 10 h; suspended timber floor with

perimeter wall air bricks U 2 W/m2 K, Y 3 W/m2 K, f 0.6, lag 10 h; north and south party

walls U 0 W/m2 K, Y 6 W/m2 K, f 1, lag 10 h. Ignore the intermediate timber first floor

thermal data as it has negligible thermal storage and time lag. Use the average leakage

standard. Adjoining houses are maintained at the same temperature. No solar shading was

used as daylight penetration was paramount. There are four occupants (parents plus two

young working people) when they are not at work during 18.00–07.00 h. Ignore heat gains

from candle lighting, cooking and water heating; bathing was likely conducted in public baths

or in front of the open coal fire in the living room.

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Answer. Housing faces east and west in streets like Hurst. All occupants were at work all day.

Large windows admitted daylight and morning sunshine into east facing bedrooms and the

living room to wake people; late evening sunshine warmed the rear elevation and yard. The

opposite side of the street did not enjoy these advantages. 26oC environmental temperature is

exceeded during 08.00–20.00 h with a peak of 28.2oC during 16.00–18.00 h. Overnight

temperature only dropped to 23.3oC so the houses remained warm in summer.

10. Traditional style small terraced 2–3-bedroom homes formed the basic accommodation

for working families in the UK since the industrial revolution of the 1700s. They still do.

Many become second homes in holiday regions. Many are larger, have gardens and a garage,

but have a look at any street of newly constructed terraced homes; they are fundamentally the

same as Hurst Street, Oldham, as in question 9. Hurst Street houses need to be modernised to

work towards meeting the objectives of the HM Government Carbon Plan 2011.

Copy the Oldham file and save as Oldham improved. The floor plan is 4.25 m wide, 9 m

long and with 2.7 m room height. UPVC framed double glazing 9 m2, with internal blinds,

face east onto Hurst Street. Heritage laws do not allow changes to the street frontage of these

houses. Rear windows are 10 m2 UPVC framed double glazing facing west. Window U 2.3

W/m2 K, Y 2.3 W/m2 K, f 1.0, lag 0 h, solar correction factor 0.15 and alternating solar

correction factor 0.11; walls U 0.2 W/m2 K, Y 2 W/m2 K, f 0.4, lag 10 h, roof U 0.2 W/m2 K,

Y 2 W/m2 K, f 1, lag 10 h; insulated suspended timber floor U 0.2 W/m2 K, Y 2 W/m2 K, f

0.6, lag 10 h; north and south party walls U 0 W/m2 K, Y 6 W/m2 K, f 1, lag 10 h. Ignore the

intermediate timber first floor thermal data as it has negligible thermal storage and time lag.

Use the tight air leakage standard, as mechanical ventilation with heat reclaim is installed.

Adjoining houses are maintained at the same temperature.

There are two occupants in the house all day and night on a particular summer weekend

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day, or public holiday. There are six lights of 70 W each on during 17.00–24.00h. Electrical

equipment, refrigerators, dishwasher, laundry, computers, communications, entertainment,

garden lighting, ornamental pond pump, exterior security lights, battery charging, cooking

and water heating provide an average electrical demand of 500 W continuously.

What effect do raising thermal insulation values, solar and ventilation control, and today’s

use of electrical energy have on a Hurst Street house peak summertime temperature and

achievement of the Government’s emission targets?

Answer. Unfortunately a bad outcome is found. 26oC environmental temperature is

continuously exceeded and has a peak of 29.1oC. The occupants will find indoor home

conditions too hot and will not accept them. Opening windows to create through flow from

the street to the back garden would help but without a prevailing wind, the house would be

very uncomfortable. The occupants have air conditioning in their cars, in shopping malls,

hotels, air transport, restaurants and in the offices where they work. They might be satisfied

by purchasing several 100 W portable fans to cool them, but will be severely tempted to

install a reverse cycle packaged air conditioning unit for their home, adding another 1 kW of

electrical demand.

Copy the Oldham improved file and save it as Oldham unpowered. Delete the occupants,

lighting and the entire electrical load. The uninhabited house remains comfortable with an

average tei of 22.9oC and a peak of 24.3oC. The problem is not the insulated house. It is the

electrical demand that occupants create which causes overheating and a need for a mechanical

cooling system. Will our craving for modern living overcome the objectives of the Kyoto

Protocol 1997 and the HM Government Carbon Plan 2011? It is possible. What do you think?

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General knowledge

11. What are the differences between the designers and users of a building?

12. Why would a very simple calculation of steady state heat gains and losses not provide

an assessment of peak summertime temperature within a building?

Answer: Because the internal air temperature is the unknown. Heat gain into the room and

heat carried away by the ventilation air flow depends on the difference between outdoor air

and indoor air temperatures. An iterative solution might solve the equations but is not easy.

Also, time lag is involved with heat flows into and out of thermal mass of the structure and

that adds further difficulty.

13. How many people use the computer building energy management system, BEMS, in a

large office building, university campus and hospital every day and week?

1. Everyone in the building.

2. Specialist maintenance contractor.

3. One person has the expertise and time to use it.

4. Nobody.

5. Everyone in the property and facilities management department.

14. Who is most interested in a macroscopic appreciation of a building?

1. Owner.

2. Facilities manager.

3. Building services engineer.

4. Employees.

5. Architect.

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15. Who is most concerned with the microscopic scale aspects of a building?

1. Architect.

2. Employees.

3. Owner.

2. Facilities manager.

3. Building services engineer.

16. Which is correct about what we have learnt from these peak summertime temperature

predictions?

1. Every UK building is comfortable all year.

2. Air conditioning is a necessity in the UK.

3. UK buildings become overheated occasionally.

4. White Tower is a better design than The Shard.

5. Nothing has been learned from history.

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2 Air conditioning systems

Air filters

1. Explain with the aid of sketches and manufacturers’ information how air filters are tested

and rated for the following tasks: air flow, face velocity, initial and final pressure drop and

dust spot efficiency.

2. Explain what is meant by the air filter terms: dry testing, dust, smoke, mists, impingement,

cyclone, washable, diffusion filter and viscous film.

3. State suitable applications for the following types of air filter, giving examples: absolute,

dry, viscous, panel, bag, electrostatic, adsorption and mechanical collectors.

4. What are the important factors to be considered and provided for air filter installations?

Applications

5. List the applications of the 16 types of air conditioning system and discuss the suitability

of each with colleagues.

6. ‘The single duct air conditioning system provides the basic design for the other

configurations that overcome its limitations’. Discuss this statement and state the ways in

which it can be adapted for multi-zone applications.

7. The variable air volume system has become very popular for office accommodation.

Explain its principles of operation and limitations. Including the topics of room air

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circulation, zone volume control, economy control of the fans, duct air static pressure

modulation and the satisfaction of user thermal and aural comfort.

8. Explain with the aid of sketches or literature how cooling coil face and bypass dampers

function, why they may be used and their purpose.

Damper schedule

9. A single duct air conditioning system with recirculation is to have variable quantities of

fresh air admitted into an office building when it is between 12oC and 23oC. Outside these air

temperatures, the minimum outdoor air of 25% of the supply quantity is to be used. Outdoor

air at 14oC can be 100% of the supply air quantity to the rooms. When the fresh air reaches

21oC outside, its proportion must commence reduction towards the minimum at 23oC. Draw a

graph of the damper operation to scale and fully explain the sequence of operation of the

system during both increasing and reducing outdoor air temperatures.

Heat pumps

10. State the advantages that can be gained by using a water source heat pump air

conditioning system capable of simultaneous cooling and heating of adjacent zones. List

suitable applications. Comment upon the maintenance required for such systems.

11. Explain with the aid of sketches and sample graphs how the supply duct air

temperatures are controlled in a dual duct air conditioning system to provide the maximum

operational economy while satisfying the users’ comfort needs.

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12. List the applications for independent air conditioning units, split systems, reversible

heat pumps, chilled ceilings and district cooling, commenting upon their design

characteristics and maintenance requirements. Acquire manufacturers’ literature for a variety

of equipment and apply them to the Sijoule PLC building.

13. Make sketches of the building you are familiar with and propose suitable designs for air

conditioning systems, drawing the components on plans and elevations.

14. Describe with the air of sketches and manufacturers’ literature how the following air

conditioning heart recovery devices save energy: recuperator, run-around coil, thermal wheel,

heat pipe, regenerator, heat pump. Comment on their suitability to buildings of your choice

and their capital and energy cost implications.

15. Identify locations where ground or air sourced heat pumps are used as a heat source or a

heat sink for an air conditioning system. Briefly describe the system, where it is located and

the capacity and application of the installation. Comment on its suitability for other locations.

Humidifiers

16. List the range of humidifiers available for use in air conditioning systems, sketch their

operation and give examples of their use.

Answer. Rotating drum, compressed air jet, spinning disc, steam injection, capillary cells,

sprayed coil, pan humidifier, ultrasonic humidifier, infrared evaporator.

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17. Discuss the statement, ‘evaporative cooling has applications but is not free’. Explain the

principles of adiabatic saturation cooling, where it may be applied, that is world location and

type of cooling requirement, and the costs of operating such systems.

Low cost cooling

18. List the ways in which free cooling maybe achieved, sketch and describe suitable

installations and where such systems could be utilised.

Answer. Ambient air, ground water, rivers or lakes, sea water, air cooled condenser, dry air

cooler, open circuit cooling tower and evaporative condenser.)

19. Demonstrate by means of descriptions, sketches and reference material how evaporative

pre-cooling can reduce the electrical energy used by a refrigerated air conditioning system;

state where such systems might be used, in which climates and for which applications.

Project building

20. Study the drawings of the Sijoule PLC building and write lists and notes on the heating,

ventilating and air conditioning systems that are likely to be needed. List the assumptions that

you make on the location and use of the building. Discuss your results with colleagues. This

exercise is suitable for groups of students to formulate different proposals and then present

them to the class.

21. Create suitable air conditioning zones for the Sijoule PLC building, stating the reasons,

and draw them onto the plans and elevations.

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22. Calculate the peak solar heat gains through the unprotected windows for each side of

the Sijoule PLC building using only the glazing heat gain data in the Air Handling Zones

section of this chapter. State the dates and times of these occurrences and the influence that

they will have on the building peak refrigeration plant capacity.

23. Form syndicates of four students to propose air conditioning designs for the Sijoule

PLC building. Each member of the group is to assume a different role:

(a) The building owner is to decide the usage of each area and the standard of internal

environmental control to be achieved. Make limitations upon the intrusiveness, likely

cost, maintenance or appearance of the systems to be proposed.

(b) The consulting engineer who is engaged for a fee calculated from a fixed percentage of

the total cost of the installation is to use the independence of this position to propose

designs that will fully satisfy the client’s stated requirements.

(c) The design and installation contractor who is engaged in a competitive situation against

other, similar companies and is to propose designs that maximise the likelihood of

gaining the contract.

(d) The manufacturer of a wide range of air conditioning products who offers a design service

free of charge to the client.

The three engineers are to formulate proposals for different air conditioning designs and

present them to the client with arguments in favour of their company’s suitability.

Presentations should be made on acetate sheets of the building drawings with coloured

sketches of the systems proposed on the plans, sections and elevations for the benefit of the

whole student group. It may be possible to integrate such group activity with architectural,

building and surveying student groups.

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What is air conditioning?

24. Discuss the statement ‘this building is air conditioned’ with reference to what this will

mean, the systems that must be installed and the possible satisfaction of user thermal comfort.

25. Explain the difference between mechanical ventilation and air conditioning.

26. Define the term low cost air conditioning. State the ways in which it can be achieved.

27. List the reasons for the air conditioning of the different categories of buildings, such as

residential, office, retail, containment and manufacturing, and write notes to explain each

reason.

28. Summarise in your own words the considerations involved in making use of outdoor air

to cool a building without the use of refrigeration. State the limitations inherent in such

designs and the ways in which outdoor air can be cooled without refrigeration.

29. Sketch the air handling arrangement for a single duct variable air temperature

recirculation system, state the necessary components and explain how the design is used to

satisfy the room cooling and heating loads.

Zones

30. List the reasons for creating air conditioning zones and the zones that may be formed

for a variety of comfort, industrial process and containment applications.

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31. State the reasons for creating different air static pressures in rooms or zones, explain

how such differences can be maintained and state pertinent applications.

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3 Heating and cooling loads

Admittance values

1. What are admittance values?

1. Solar heat gain factors for windows and opaque structures.

2. The opposite of resistance values.

3. The number of people who can pass through the buildings’ entry and transportation

systems at peak flow periods.

4. Always twice the thermal transmittance value.

5. Thermal factors evaluating heat flows into thermal storage of the structure.

2. Which does not apply to admittance values?

1. Y W/m2 K.

2. Reciprocal of U value.

3. Used instead of thermal transmittance in certain circumstances.

4. Expresses heat flow inwards to a heavy mass structural component.

5. Used for highly intermittently heated buildings.

Air quality

3. Which of these is not correct about indoor air quality?

1. Cannabis smoke contains carbon monoxide, benzene and toluene.

2. Tobacco smoke contains carbon monoxide, benzene and toluene.

3. Internal combustion engines emit carbon monoxide and many other atmospheric

pollutants.

4. Normal breathing increases the carbon dioxide content of room air.

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5. Normal breathing increases the carbon monoxide content of room air.

4. Where could carbon monoxide, benzene and toluene gases have come from if detected

within an occupied building?

1. Water chiller plant room refrigerant leakage.

2. Hydrocarbon natural gas combustion water heating plant.

3. Drains and sewers.

4. Cleaning fluids and off-gassing from furnishings.

5. Outside air intake to air handling unit, AHU, or people smoking tobacco or cannabis.

5. Which of these is where indoor odours, vapours and gases come from?

1. Radon gas emanating from the ground beneath the building.

2. Carbon monoxide from traffic.

3. People, our clothes and what we put on our skin.

4. Passively acquired cigarette smoke prior to entry into the office building.

5. Last night’s spicy meal.

6. Are any of these correct for biological effluent?

1. Is too complicated to be measured.

2. Comes from many sources within the working environment.

3. From one office worker in a 10.0 m2 working space is standardised at 1.0 olf.

4. Is counteracted by plants within the occupied building, particularly with open atria.

5. We walk into the building with odours on our clothes.

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7. Which of these are correct for excellent air quality in a building?

1. May need very high room air change rates.

2. May need outside air to be collected from the roof of a tall city centre building.

3. May be unachievable where the building is located in a polluted industrial area.

4. Can be improved with air filtering equipment.

5. Mainly impractical due to its high cost.

8. Where does poor indoor air quality come from?

1. Toxic substances that occupants bring into the building by hand or on their clothing.

2. Inward leakage of outdoor air (outdoor air may be cleaner).

3.Insufficient fresh air ventilation quantity (meaning ability to remove internally generated

pollutants).

4.Volatile organic compounds released into the building air from furnishings, cleaning

fluids and electro-mechanical equipment.

5. Lack of adequate air filtration systems (this is not a source of pollution).

9. Which may be related mainly to sick building syndrome?

1. Excessively cleaned and polished interior surfaces.

2. Stuffy atmosphere.

3. Eye, nose and throat irritation, headache, nausea, breathing difficulties.

4. Absenteeism.

5. General commercial noise, building services intrusive noise, fluorescent light flicker or

glare.

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10. Which is the internal air quality recommended upper limit for percentage of occupants

detecting any odour?

1. 50.

2. 40.

3. 30.

4. 20.

5. 5.

11. Odours are measured in what units?

1. Ole’s.

2. Fanger’s.

3. Decipol.

4. Olf.

5. Millilitres per square meter of floor area.

12. Air quality within a building depends upon:

1. Number of people indoors.

2. How much and where air pollutants are found.

3. Relative humidity of room air.

4. Dry bulb air temperature.

5. Plants, animals and furnishings in the building.

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13. Indoor odours, vapours and gases come from:

1. Ingress from outdoor environment.

2. The air conditioning systems.

3. The basement car park of the building.

4. Humans, animals, plants and furnishings within the building.

4. Dust, pollen and materials in waste paper bins.

14. Indoor odours, vapours and gases come from:

1. Cleaning fluids used overnight.

2. New furniture, carpets, floor coverings, sealants and adhesives.

3. Old furniture, carpets and floor coverings.

4. Personal hygiene products.

5.Cigarette smoke, diesel engine exhaust, road tar, painting work being done and creosote

used on roofing.

15. Indoor odours come from:

1. Radon gas emanating from the ground beneath the building.

2. Carbon monoxide from traffic.

3. People, our clothes and what we put on our skin.

4. Passively acquired cigarette smoke prior to entry into the office building.

5. Last night’s spicy meal.

16. Which is the likely outcome from inadequate outdoor air ventilation?

1. Comfortably warm houses and offices.

2. Less draught.

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3. Suppression of house dust mites, condensation and mould growth due to warmer

environment.

4. Inadequate removal of house dust mites, condensation and potential mould growth.

5. Lower energy costs.


1. Reduced fire risk.

2. Lower cost ducted ventilation system.

3. Suppression of hazardous pollutants such as oxides of nitrogen from vehicles, volatile

organic compounds from furnishings and possible mould growth.

4. Excess of hazardous pollutants such as oxides of nitrogen from vehicles, volatile

organic compounds from furnishings and possible mould growth.

5. Reduced contamination produced from tobacco smoke.

18. Which of these can affect asthma sufferers?

1. Excess of outside air ventilation.

2. House dust mites and mould spores.

3. Warm indoor air.

4. Humid and warm indoor air.

5. Matters other than those related to ventilation.

19. Which of these is not a contaminant of indoor air quality, IAQ?

1. Tobacco smoke.

2. Volatile organic compounds, VOC, from cleaning fluids.

3. Nitrogen.

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4. Carbon monoxide.

5. Nitrogen dioxide.


1. Pipe tobacco smoke.

2. Volatile organic compounds, VOC, from new furnishings and floor coverings.

3. Carbon tetrachloride.

4. Nitrogen trioxide.

5. Oxygen.


1. Cigar smoke.

2. Carbon dioxide.

3. Benzene, toluene, formaldehyde and ethylene glycol.


5. NOx.

22. When carbon dioxide level in occupied rooms is sensed for control of ventilation

airflow, what is the maximum set point used, approximately, in parts per million, ppm?

1. 100.

2. 700.

3. 250.

4. 1000.

5. 5000 (health limit of CO2 in air).

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23. What is radon?

1. Solar flare particles passing through earth’s atmosphere.

2. Fire extinguishant.

3. Fluorinated hydrocarbon refrigerant.

4. Radioactive gas from granite ground.

5. Rapidly decaying radioactive isotope.

24. What form of reduction occurs when ventilation removes tracer gas or contaminant?

1. One air change eliminates it.

2. Linear rate of decay.

3. Logarithmic rate of decay.

4. Exponential rate of decay.

5. Polynomial rate of decay.

25. Which is not true about viruses and bacteria within buildings?

1. People and animals bring bacteria indoors.

2. Indoor potted plants are a source of bacteria.

3. Viruses and bacteria are airborne.

4. Water and damp surfaces release viruses and bacteria into room air.

5. Influenza, measles, tuberculosis and chicken pox are transmitted by air.

26. Which of these is a correct reason for outdoor air ventilation rate control and provision?

1. Removes dust mites.

2. Removes PM10 particles which are all larger than 10 μm diameter.

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3. Maintains high humidity within a building to ensure mould spores and dust mites

remain.

4. Allergic skin reactions and asthma have no causal relationship to dust mites.

5. There is no correlation to chronic illness and mortality from ventilation.

27. We sense odours by:

1. Identifying smells.

2. Breathing onto others.

3. A measuring instrument.

4. Tasting them in our mouth.

5. Olfactory response.

28. Indoor odour quality:

1. Decimetre is the measuring unit for odour.

2. Indoor air quality is measured on the decibel scale.

3. Indoor odour is very difficult to measure because it cannot be seen.

4. Measurement remains a subjective science.

5. Sick buildings have odorous air.

29. Concentration of odorous pollutants is measured by:

1. Number of people per 100 m2 of floor area in the building.

2. Age profile of the occupants.

3. Outdoor air ventilation rate in litre/s per person.

4. Decipol units.

5. Olf units.

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30. We perceive odours by using which units?

1. Blockage of nasal passageways.

2. Olf units.

3. Decibel units.

4. Decipol units.

5. Consensus of agreement among occupants.

31. The decipol unit is:

1. Basic unit of sound.

2. How we evaluate pollutants through olfactory sensation.

3. The name of a sound level meter.

4. Same as the humans’ sniff test.

5. A taste test on the scale of 1 to 10.

32. One olf is:

1. A very sick building.

2. One person sniffing a single odour for 10 seconds.

3. Emission rate of biological effluents from one person.

4. Standardised emission from 1.0 m2 of building or material surface area.

5. Emission rate of biological effluent from 1.0 kg of polyacrylonitrile (PAN) resin at room

temperature.

33. Olf refers to:

1. A standard unit of odour from any source.

2. Ole Fanger who devised comfort measurements.

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3. Olfactory sensors in the nose.

4. Number of olfs refers to different levels of human activity.

5. Units used for tasting odours.

34. Biological effluent:

1. Is too complicated to be measured.

2. Comes from many sources within the working environment.

3. From one office worker in a 10.0 m2 working space is standardised at 1.0 olf.

4. Is counteracted by plants within the occupied building, particularly with open atria.

5. We walk into the building with odours on our clothes.

35. Biological loading:

1. From one office worker is around 0.10 olf/m2.

2. Of a smoker while smoking is around 25.0 olf/m2.

3. Of a smoker when not smoking is around 6.0 olf/m2.

4. Within a gymnasium in use is around 11.0 olf/m2.

5. Within a low pollution office building with an absence of smoking is around 0.20

olf/m2.

36. Air quality may be deemed satisfactory when:

1. 100% of the full-time occupants are satisfied.



4. Complaints cease.

5. Odours have been eliminated.

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37. Air quality within a building:

1. Is easily achievable.

2. Cannot be achieved in buildings over 15 years old.

3. Deteriorates with building age.

4. A compromise between conflicting requirements and cost.

5. Only needs simple instrumentation to analyse.

38. Excellent air quality in a building:

1. May need very high room air change rates.

2. May need outside air to be collected from the roof of a tall city centre building.

3. May be unachievable where the building is located in a polluted outdoor industrial

environment.

4. Can be improved with air filtering equipment.

5. Is mainly impractical due to its high cost.

39. Where does dust and dirt appear in ducted ventilation and air conditioning systems?

1. Blown through air ducts, deposited in rooms and removed by cleaning and vacuuming.

2. Retained in air handling unit air filters.

3. Nowhere but in air filters.

4. On fan blades and casings.

5. Inside air ducts and in all items of plant.

40. What can be done to maintain the health and safety of the internal surfaces of ducted

ventilation and air conditioning systems?

1. Replace aged air ducts.

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2. Increase air velocity to blow deposits out of ducts and terminal units outside of

occupied hours.

3. Change air filters regularly.

4. Internal visual inspection, compressed air brushing, scraping and vacuum cleaning.

5. Nothing more than maintaining air filters to keep air and ducts clean.

41. Where can sinusitis, asthma, pneumonia and skin dermatitis originate?

1. Mould spores in warm humid uncleaned air and water building services systems.

2. Contaminated outdoor air.

3. Low air humidity.

4. Contacting people with breathing infections.

5. Warm humid air in crowded buildings or transportation.

42. How can eye and nasal irritation occur?

1. Airborne infections from other people.

2. Warm humid air within the building.

3. Warm low relative humidity air within buildings.

4. Clogged air conditioning filters.

5. Excessive dust in room air.

43. What can cause eye and nasal irritation occur?

1. Low relative humidity or volatile organic compounds, VOC, released into room air

from furnishings, cleaning fluids, paint and chemicals.

2. Badly fitting contact lenses.

3. Unclean conditioned air.

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4. Airborne bacteria.

5. Common cold and flu.

Around the world

44. Explain how condensation can occur both in cool climates such as the UK and in hot

humid tropical climates, causing damage to buildings, plant and equipment. Sketch examples

of how such risks are combated.

45. Provide examples of comfort conditions for sedentary workers within buildings in

different climate regions, namely, Arctic, northern Europe, Middle East, desert,

Mediterranean, equatorial and sub-tropical. Identify each climate location being described.

State which form of air conditioning is used in each location and give reasons for their

suitability.

46. List the eight climate regions found within the tropics. State a typical location for each

and what types of air conditioning system are used for commercial and domestic buildings.

What do people without access to air conditioning do in each of the eight regions to maintain

their living conditions? Would you abandon your present lifestyle to live in any or all of these

eight regions if you had no access to air conditioning, and why?

47. Use the file Around the world.xls to compare air conditioning cooling loads for different

locations and climates. Add further locations and data as needed. Copy the file Shard in

Dubai.xls with another name and use it to estimate air conditioning loads and costs around the

world as you decide.

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48. Use the file Around the world.xls and copy the file Shard in Dubai.xls with another

name and use it to estimate air conditioning loads and costs as if it were built in Doha, Qatar.

Find the climate data for Doha. Comment on what you find.

Buildings’ responses

49. Which buildings have a fast response, such as within an hour, to variations in outdoor

air temperature, sunshine, cloud and wind?

1. Concrete and steel framed 20-storey offices.

2. Traditional stone churches.

3. London underground railway stations.

4. Large volume single-storey industrial buildings having lightweight thermal insulation to

corrugated sheet steel wall and roof cladding, for example, aircraft hangers, car

factories.

5. Small prefabricated buildings, transportable, temporary site accommodation, caravans,

tents and marquees.

50. Which buildings have a slow response, several hours, to variations in weather?






factories.

5. Small prefabricated buildings transportable, temporary site accommodation, caravans,

tents and marquees.

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51. Which areas of a building do not respond to outdoor weather variations?

1. Store rooms.

2. Most offices.


4. Areas more than 5.0 m from external walls.

5. Zones that are air conditioned.

52. Solar radiation, wind and outside air temperature can cause greater discomfort where?

1. Buildings are on exposed hill top sites.

2. Deciduous trees provide shading to windows

3. Internal controllable window blinds are not used.

4. Sedentary occupants are located within 5.0 m of perimeter glazing.

5. Central core offices are well away from windows.

53. Where can a building of any size have zones?

1. Rooms facing a similar orientation.

2. Spaces occupied at the same times.

3. Rooms having the same number of people.

4. Areas served by one type of air conditioning system at the same time of day.

5. Where the internal air temperature control system only needs one sensor.

54. Which of these buildings have a slow response, several hours, to variations in weather?


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factories.

5. Small prefabricated buildings, transportable, temporary site accommodation, caravans,

tents and marquees.

Combined heat and power

55. List and discuss the merits of the methods used to generate electrical power. What

should the UK policy be for the next 100 years in relation to the HM Government Carbon

Plan 2011? Should any country rely upon another country for its power supply in the long

term? Will one European country become the dominant supplier of power, if so, what would

be the advantages and disadvantages of such a policy?

56. Discuss the application of CHP systems in relation to density of heat usage, local and

national government policy, possible plant sites, complexity of existing underground services,

ground conditions, costs of competing fuels, type and age of buildings, traffic disruption

during installation and better control of pollution. (The term ‘density of heat usage’ refers to

the actual use of heat in megajoules per unit ground plan area m2, including all floors of

buildings and appropriate industrial processes requiring the sort of heat to be sold.)

57. What does cogeneration mean?

1. On-site electrical generator.

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2. Contractor-operated diesel generator providing on-site uninterruptible power supply,

UPS.

3. Heat output from on-site generator water cooling system used to heat the building.

4. Combination of on-site standby generation with public electricity supply.

5. Combination of electric supplies, heating and cooling systems in a complex site.

58. What does tri-generation mean?

1. No such thing.

2. Three systems of electricity generation on a site.

3. A site where heating, cooling and water heating are all provided by electricity.

4. Diesel or gas engine drives an alternator for site electricity generation, waste heat used

to produce hot water heating as well as chilled water through absorption refrigeration.

5. Space heating, water heating and chilled water for air conditioning all provided by one

fuel source.

Combustion

59. Which statement relating to combustion is correct?

1. CO2 means two molecules of carbon monoxide.

2. 2O2 means two molecules of oxygen.

3. 2H2O means two atoms of hydrogen plus two atoms of ozone.

4. CO is carbon oxide.

5. SO2 means sodium dioxide.

60. What does stoichiometric ratio mean?

1. Optimum efficiency.

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2. Maximum oxygen in flue gas.

3. Maximum carbon dioxide in flue gas.

4. Poor combustion.

5. 100% excess air provided.

61. Where are oxides of nitrogen created?

1. Nitrogen is inert, it cannot oxidise.

2. Hydrocarbon combustion.

3. Electrolysis of air from electric sparks or lightning.

4. Chemical reaction within lungs.

5. Leakage of nitrogen from high pressure liquid storage.

Degree days

62. Which is degree day load factor not relevant to?

1. Calculation of heating system kW load for design.

2. Ratio of degree days from meteorological data.

3. Minimum outside air temperature for design.

4. Seasonal weather variability.

5. Maximum possible degree days for the locality.

63. Degree ays are which of these?

1. University degree award ceremony days.

2. Number of air temperature degrees in one day.

3. Measures severity of winter weather.

4. Also used for calculation of summer cooling energy consumption.

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5. Not used to calculate anything.

64. Which is not correct about degree days?

1. Applied to normally occupied buildings.

2. Predicts summer cooling energy consumption.

3. Based on heat gain and heat loss balance at an outdoor air temperature of 15.5oC in the

UK.

4. A 24 hour mean outdoor air temperature of 8oC produces 7.5 degree days.

5. An energy management plan relates GJ consumption to degree days.

65. Which is degree day load factor not relevant to?

1. Calculation of heating system kW load for design.

2. Ratio of degree days from meteorological data.

3. Minimum outside air temperature for design.

4. Seasonal weather variability.

5. Maximum possible degree days for the locality.

Discounted cash flow, DCF, NPV, IRR

66. How can Discounted Cash Flow calculation aid analysis of an energy-saving project?

67. State what Net Present Value of an investment decisions means.

68. State how Internal Rate of Return of a cash flow is an aid to making the decision to

invest.

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Energy audit

69. State the function of an energy audit. What data are collected? How are the data

presented? What is likely to be the most serious barrier to data collection?

70. Explain the term ‘degree day’ and state its use.

71. How is the load factor calculated and how is it used?

72. A factory uses 20000 1 of oil for its heating and hot-water systems, 160000 kWh of

electrical power and 300000 kWh of gas for furnaces in a year. Fixed charges are £800 for the

oil, £700 for the electrical equipment and £1200 for gas equipment. Use the data provided in

this chapter and current energy prices to produce an overall energy audit based on the

gigajoule unit and find the average cost of all the energy used.

73. Which of these adequately describe an energy audit of a building?

1. Points out what building operators could do to save energy.

2. Are only for cosmetic appearance of doing something to reduce greenhouse emissions.

3. Identifies and quantifies viable energy-saving investments.

4. Concentrates on finding almost zero cost short term payback energy-saving

opportunities.

5. Only analyses technical projects and not financial investment criteria.


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1. Summary of all energy sources.

2. Description of how energy is used on a site.

3. Comprehensive analysis and report of all energy usage.

4. Does not need to analyse or make recommendations for energ- saving projects on the

site.

5. Only ever done once in the service period of a building.


1. Financial audit of energy purchases..

2. Analysis of CO2 emissions.

3. Comprehensive report of energy use and quantifies viable energy-saving investments.

4. Lists lowest cost short term payback energy-saving opportunities.

5. Reports technical projects as possibilities.

76. Energy audits only look at, which?

1. Types of primary energy source used.

2. Electrical energy consumption.

3. Where energy is being wasted.

4. Where high capital cost energy-saving projects are identifiable.

5. Everything relevant.

77. Which of these adequately describe an energy audit?

1. Can be done adequately by anyone.

2. Ignores energy wastage where it is normal industry practice.

3. Identify the energy effectiveness of most of the site.

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4. Only analyses heating, ventilating, air conditioning and electrical lighting energy use.

5. Conducted by an experienced and qualified energy auditor.

Energy cost

78. Calculate the annual cost of a gas-fired heating system in a house with a design heat

loss of 30 kW at -2°C for 16 h per day, 7 days per week for 30 weeks in the year. Use the data

provided in this chapter and the current fuel price.

79. Find the total annual cost of running a gas-fired heating and hot-water system in a house

with four occupants if its design heat loss is 32 kW. Maintenance charges amount to £160 per

year.

80. Discuss the statement, ‘Economic thickness of thermal insulation of houses is no longer

the relevant argument’.

81. A city centre building in England has a predicted energy consumption of 1500000 kWh

per year for only the space heating system. The design engineer is to recommend the energy

source and system type to be used on the basis of minimising the greenhouse gas emissions.

The average seasonal usage efficiency of the alternative systems are 95% for electrical

heating systems of various types, 75% for gas-fired radiator heating system, 65% for coal-

fired radiator heating system and 75% for an oil-fired ducted warm air heating system. How

might renewable energy sources be used? Calculate the carbon emission in tonnes per year

and make a suitable recommendation to the client.

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General knowledge

82. How can heat leakages due to inadequate thermal insulation and damaged pipes or

cables be detected?

83. How can building designers help users feel comfortable in their workplace?

1. Provide perfect indoor air conditions.

2. Meet everyone’s expectations.

3. Provide some means of individual control over their microclimate.

4. Each workstation linked to the building management system computer so that the

control system polls user feedback and adjusts set points accordingly.

5. Minimise greenhouse gas emissions and regularly survey user’s comfort responses to

minimise complaints.

84. State the factors that are taken into account when designing for the provision of

ventilation with outdoor air.

85. List the atmospheric pollutants that are likely to be present within normally occupied

buildings. Identify those pollutants that are used for the design of the ventilation system, the

filtration equipment, acoustic insulation and general maintenance during occupation.

86. State why continuous logging is of value to the energy audit engineer, environmental

system design engineer, building designer and building occupants, giving reasons for your

statements.

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87. Where does poor indoor air quality come from?

88. Human thermal comfort is related to which of these?

1. Sleeping cycle.

2. Metabolic activity.

3. Time of day.

4. Clothing.

5. Location.

89. Human thermal comfort is related to:


2. Outdoor relative humidity.

3. Wind vector.

4. Age.

5. Crowding.

90. Where does Legionnaires’ disease originate?

1. French Foreign Legion.


3. Cold water storage tanks.

4. Hot water storage cylinders.

5. Aerosols from cooling towers, shower heads, spray taps, spa baths and humidifiers.


1. Naturally occurring bacteria in soil and water.

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2. Rainwater.

3. Uncleaned air conditioning ducts.

4. Stored water in building services systems.

5. Carpet dust.

92. Overall efficiency of a heating system includes which of these?

1. Mining and drilling energy expended in gaining the fuel.

2. Energy expended in cleaning up the global environment pollution after using the fuel or

energy source.

3. Combustion of the fuel delivered to the site.

4. Heat lost from the building.

5. Effectiveness of the building in retaining warmth.

93. Which is not used in heating system fuel costs comparison?

1. Cost to produce a kWh or GJ of heat energy.

2. Overall efficiency of the heating system.

3. Means used to deliver energy source to the site.

4. Data table showing all energy sources to a common basis.

5. Total of all costs to use the energy source for a year.

94. What is an energy use performance factor, EUPF?

1. No such thing.

2. The efficiency of using each primary energy source.

3. Compares the efficiency of using hydrocarbon fuel sources with nuclear generated

electricity.

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4. Logical way to compare the use of various energy sources.

5. Everyone devises their own ratios.

95. Which would not be an energy use performance factor, EUPF?

1. ₤ per m2 floor area for a month or year of a single energy source or fuel.

2. ₤ per m2 floor area for a month or year of all energy sources or fuels.

3. Energy use kWh per Degree Day.

4. Energy use MJ per person per year.

5. kWh/yr energy-saving proposal.

×

96. Which of these is not a correct multiple?

1. kJ = 103 J.

2. MWh = 1000 W × 1 h.

3. 1 GJ = 106 kJ.

4. 1 mm = 10−3 m.

5. 1 GW = 1000 MW.

Heat gains

97. State the sources of heat gain that will affect the internal thermal environment in

residences, offices, retail premises, an atrium in a shopping concourse, a pharmaceutical

manufacturing building, an air conditioning plant room, a railway passenger carriage, a motor

car, an aeroplane and an entertainment theatre.

98. Explain how heat gains to an occupied building have intermittent characteristics.

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99. Describe the angular position of the sun in relation to the four walls and the roof of a

building. Define each term used.

100. Explain what is meant by the incidence of solar radiation upon a surface and define how

it is found for vertical walls, horizontal roofs and sloping surfaces. State the reason for

needing to know the incidence in the calculation of solar radiation heat gains to a surface.

101. A surveyor needed to assess the height of a tower and measured an angle of 52o from

the ground to the top of the tower at a distance of 35m from it. Calculate the building height.

Answer. 44.8 m.

102. A 19-storey office building was being built on a hillside and the surveyor needed to

check the height of the structural steelwork during construction. The nearest point of the top

of the structure was at an elevation of 40o from the surveyor’s position and 55 m horizontally

away. The furthest point of the steel frame down the hill was 75 m from the surveyor when

measured down the slope of the hill and at decline angle of 12o. Calculate the overall height of

the frame and the average floor to floor height.

Answer. Total height 46.15 m + 15.593 m, 61.744 m, 3.25 m each.

103. A building has a side 30 m long that slopes forwards from ground level at 78o from the

horizontal. The roof line is at 66o from the ground at a distance of 32 m from the foot of the

wall. Calculate the vertical height of the building, the length of the sloping face and the

sloping face area.

Answer. Vertical height 20.139 m, sloping face length 20.59 m and area 617.7 m2.

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104. A vertical wall in London faces south. At 10.00 hours sun time on 22 June the solar

altitude is 55o and solar azimuth 128o. Calculate the wall solar azimuth and incidence angles.

Answer. 52o, 69.3o.

105. Atrium glazing in Glasgow, latitude 55o 52'N, faces west and slopes 12o forwards from

the vertical. The sun time is 13.00 hours on 21 August, the solar altitude is 45o and the solar

azimuth is 201o. The intensity of the direct solar radiation normal to the sun is 840 W/m2.

Calculate the incidence angle and the solar intensity upon the glazing.

Answer. D 69o, F 87o, 44.3 W/m2.

106. A flat plate solar collector near Sidney at latitude of 35o S slopes at 45o to the horizontal

and faces north. At 12.00 hours sun time on 21 December the solar altitude is 78o, azimuth 0o

and direct intensity normal to the sun is 918 W/m2. Find the incidence angle by sketching the

angles and not applying the general equation then calculate the solar intensity that is normal to

the collector surface.

Answer. D 0o, F 33o, 686.9 W/m2.

107. A solar collector in south east England faces due south at an angle of 40o to the

horizontal. Calculate the maximum solar irradiance and state when this will occur.

Answer. From CIBSE the maximum may occur on 22 September at 12 00 h, ITHd 625 W/m2,

ITVd 710 W/m2, IdHd 190 W/m2, ITSd 878.4 W/m2. Check other dates and times.

108. A window facing south is 4 m long and 3 m high and has a shaded area of 5 m2. Solar

altitude is 55o, solar azimuth is 12o east of south, direct solar irradiance normal to the sun is

540 W/m2 and diffuse irradiance is 210 W/m2. The glazing transmissibility of direct and

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diffuse irradiances are 0.74 and 0.69. Calculate the solar heat gain transmitted through the

glass.

Answer. IDVd 303 W/m2, QD 1569.5 W, Qd 1738.8 W, total 3308.3 W.

109. The upper glazing on an atrium slopes at 60o to the horizontal and faces southeast. It is

2 m long and 2 m high and has a shaded area of 1 m2. At 10.00 h on 22 September the design

direct solar irradiance on a horizontal surface 𝐼𝐷𝐻 is 355 W/m2. The design direct solar

irradiance on a vertical surface 𝐼𝐷𝑉 is 525 W/m2. The design diffuse irradiance 𝐼𝑑𝐻 is 160

W/m2. The glazing transmissibility of direct and diffuse irradiances are 0.46 and 0.4.

Calculate the solar heat gain transmitted through the glass.

Answer. IDSd 632 W/m2, QD 872 W, Qd 256 W, total 1128 W.

110. Find the glass temperature tg, total heat flow into the room Q and the total transmittance

T for 6 mm silver reflective float glass that is in a total solar irradiance of 625 W/m2 at 08.00

h on 21 June facing east. The external and internal air temperatures are 31oC and 23oC. The

absorptivity A of the glass is 0.29, the transmissibility T is 0.43 and reflectance R is 0.28. The

glass is low emissivity and has values of Rsi 0.3 m2 K/W and Rso 0.07 m2 K/W.

Answer. tg 39.8oC, Q 324 W/m2, total T 0.52.

111. Find the glass temperature tg, direction of heat flow Q and the total transmittance T for

10 mm bronze tinted heat absorbing float glass that is in a total solar irradiance of 175 W/m2

at 13.00 h on 21 December facing west. The external and internal air temperatures are −2oC

and 18oC. The absorptivity A of the glass is 0.67, the transmissibility T is 0.29 and reflectance

R is 0.04. The glass is high emissivity and has values of Rsi 0.12 m2 K/W and Rso 0.03 m2

K/W due to its exposed location.

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Answer. tg 4.8oC, Q −59 W/m2, total T −0.34, heat flow outwards from the room.

112. A new light coloured flat roof of 25 m × 15 m is over a production area that is to be

maintained at a resultant temperature of 19oC by an air conditioning system. The thermal

transmittance of the roof is 0.4 W/m2 K and the admittance is 0.7 W/m2 K. The 24 hour

average outdoor environmental temperature for a roof on 23 July in Southampton is 22oC.

The roof decrement factor is 0.99 and its time lag is 1 hour. The outdoor environmental

temperature at 13.00 h is 37.5oC. The room height is 3 m and it has 0.5 air changes per hour

due to the infiltration of outdoor air. Calculate the room cooling load through the roof for

14.00 h.

Answer. Fu 0.54, Fv 0.92, Fy 0.96, Qu 264 W, 𝑄𝑢� 2402 W, net Qu 2666 W.

113. A south facing office wall is 30 m long and 4 m high. The thermal transmittance of the

wall is 0.33 W/m2 K and the admittance is 2.4 W/m2 K. The office has a volume of 1440 m3

and is to be maintained at a resultant temperature of 20oC by an air conditioning system. The

24 hour average outdoor environmental temperature for a dark coloured wall on 23 July in

Bournemouth is 26oC. The wall decrement factor is 0.35 and its time lag is 9 hours. The

outdoor environmental temperature at 08.00 h is 25.5oC. The room has 1.5 air changes per

hour due to the infiltration of outdoor air. Calculate the room cooling load through the wall

for 17.00 h.

Answer. Fu 0.98, Fv 0.5, Fy 0.88, Qu 466 W, 𝑄𝑢� -12 W, net Qu 454 W.

114. A south east facing top floor London office is similar to that shown in figure 3.14. The

exposure is normal. The office is to be maintained at a resultant temperature of 19oC. There

are two sedentary occupants and two continuously used computers having power

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consumptions of 250 W each. The air conditioning plant operates for 10 hours per day. There

are 1.5 air changes per hour due to natural infiltration of outdoor air. The adjacent offices,

corridor and office below, are maintained at the same temperature as the example office.

Room volume V is 600 m3. The glazing cooling load peak is 313 W/m2 at 11.00 h on 22

September and the correction factor for glass and shading types is 0.55. Use the data provided

and calculate the peak cooling load for the room air conditioning unit. The thermal data are

shown in tables 3.6 and 3.7.

Table 3.6 Heat transfer data for question 18

Surface A m2 U W/m2 K (AU) Y W/m2 K (AY) f Lag h

Glass 25 3.3 3.3 1 0

External wall 60 0.3 2.7 0.28 8

Internal wall 100 1.5 3 0.72 1

Floor 200 1.2 2.4 0.7 1

Roof 200 0.25 0.8 0.99 1

∑𝐴 = ∑𝐴𝑈 = ∑𝐴𝑌 =

Table 3.7 Sol-air data for question 18

Surface Lag h 24 h teo 24 h tao time h teo Swing �̃�eo

External wall 8 23.5 15.5 0300 10.5

Roof 1 20 15.5 1000 33.5

tao �̃�ao

Window 0 - 15.5 1100 17

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Answer. Solar gain through the glazing 4304 W, 24 hour mean conduction through the

structure −151 W, swing in the conduction gain −329 W, ventilation air infiltration −820 W,

occupancy gain 180 W, electrical equipment emission 500 W, total heat gain 3684 W.

115. The top floor of an office building in Bristol is to be maintained at a resultant

temperature of 20oC. Use the data provided to calculate the peak cooling load for the top floor

office.

The air conditioning plant operates for 10 hours per day. There is 0.75 of an air change per

hour due to natural infiltration of outdoor air and 0.25 of an air change per hour from

uncooled air entering from the rooms on the floors below. Only the top floor of the building is

cooled. The lower floors are expected to be at an air temperature of 26oC at times of peak

cooling load. The top floor is a rectangular open plan general office 40 m long, 15 m wide and

3.5 m high with one long side facing south. There is 40 m2 of glass on the north and south

sides but no glazing on the east and west walls. There are 40 occupants each emitting 90 W,

20 computers of 200 W each, one photocopier of 400 W and 10 permanently used fluorescent

lamps of 65 W each. The thermal data are shown in Ttables 3.8 and 3.9.



S glass 5.7 5.7 1 0

N glass 3.3 3.3 1 0

S wall 0.3 2.5 0.3 8

E wall 0.4 3 0.7 9

W wall 0.4 3 0.7 9

N wall 0.3 2.5 0.3 8

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floor 1.8 2.8 0.7 1

roof 0.25 0.9 0.9 2

∑𝐴 = ∑𝐴𝑈 = ∑𝐴𝑌 =

It is expected that the peak cooling load for the top floor will occur at the time and date of

the peak irradiance on the south glazing, that is noon sun time on 22 September and 21

March. This might not be the case and other times and dates could be analysed for

comparison. South single glazing has a cooling load of 333 W/m2 and a correction factor of

0.77, the north double glazing has a cooling load of 104 W/m2 and a correction factor of 0.95.


Surface Lag h 24 h teo 24 h tao time h teo Swing �̃�eo

S wall 8 25 15.5 0400 10.5

E wall 9 20.5 15.5 0300 10.5

W wall 9 20.5 15.5 0300 10.5

N wall 8 17 15.5 0400 10.5

roof 2 20 15.5 1000 33.5

tao Swing �̃�ao

S glass 0 - 15.5 1200 18.5

N glass 0 - 15.5 1200 18.5

Answer. Fu 0.94, Fv 0.93, Fy 0.89, F2 1.17, solar gain through the glazing 14208 W, 24 hour

mean conduction through the structure −1554 W, net swing in the conduction gain 2324 W,

outdoor ventilation air infiltration −912 W, indoor air infiltration 1216 W, occupancy gain

3600 W, electrical equipment emission 5050 W, mean conduction gain from below 6545 W,

total net gain 30477 W, 30.477 kW, 14.5 W/m3 of the office volume.

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116. Calculate the net heat transfer through a west facing single glazed window for 22 April

at 14.00 h when the cooling load is 207 W/m2 with a shading correction factor of 0.77, Fu/Fv

is 0.9, Fu/Fy is 0.95, outside air temperature is 14.8oC, room resultant temperature 21oC, 24

hour mean external air temperature is 9oC, window U value is 5.7 W/m2 K and dimensions are

2.5 m × 1.5 m.

Answer. 485 W.

117. List the ways in that the south facing office in example 3.17 could be made comfortable

with passive architectural changes and mechanical cooling methods.

118. A west facing Plymouth office of 15 m × 5 m × 3 m high has double glazed gold

coloured heat reflecting window openings of 25 m2. The surrounding rooms are all similar.

There are six occupants emitting 90 W and five electrical items of 150 W each. The office is

used for 8 hours in each 24 hours. Windows and door are shut at other times and the

ventilation rate is 1.5 air changes per hour. Use the data provided to estimate the 24 hour

mean and peak internal environmental temperatures. The peak solar irradiance on a west

facing vertical window is 625 W/m2 at 16.00 h on 21 June in south east England and the daily

mean is 185 W/m2. The mean solar gain correction factor for the glazing without blinds is

0.25 and the alternating factor is 0.2. The thermal data are shown in tables 3.10 and 3.11.


Surface A m2 U W/m2 K (AU) Y W/m2 K (AY) f lag h

Glass 3.3 3.3 1 0

External wall 0.57 3.6 0.31 9

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Internal wall 1 3.6 0.62 1

Floor 2 4.3 0.59 2

Ceiling 2 6 0.46 3

∑𝐴 = ∑𝐴𝑈 = ∑𝐴𝑌 =


Surface Lag h 24 h teo 24 h tao time h teo Swing �̃�𝑒𝑜

External wall 9 24.5 16.5 0700 15.5


Window 0 - 16.5 1600 22

Answer. Total mean gain Q 1586 W, mean tei 24.7oC, total swing in gains 𝑄𝑡� 4095 W, 𝑡𝑒𝚤�

3.2oC, peak tei 27.9oC.

119. A vehicle production factory that was constructed in 1960 at Southampton is 100 m ×

100 m × 10 m high and has no glazing. The structural steel frame is clad in corrugated metal

sheet with no insulation for the walls and a lightweight flat roof, all painted white externally.

The workforce of 200 occupies two 8 hour shifts per 24 hours, emitting 110 W each. Heat

producing motors, lights, tools and processes generate 50 kW during the working periods. The

100% outdoor air mechanical ventilation systems operate for 24 hours per day and 7 days per

week and produce one air change per hour. The thermal data are shown in tables 3.12 and

3.13. Use the data provided to estimate the peak internal environmental temperature.



S wall 5.7 5.7 1 0

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E wall 5.7 5.7 1 0

W wall 5.7 5.7 1 0

N wall 5.7 5.7 1 0

Floor 1.7 5.2 0.72 3

Roof 1.1 1.2 0.99 1

∑𝐴 = ∑𝐴𝑈 = ∑𝐴𝑌 =


Surface Lag h 24 h teo 24 h tao Time h teo Swing �̃�eo

S wall 0 22.5 19 1200 36

E wall 0 22.5 19 1200 26.5

W wall 0 22.5 19 1200 26.5

N wall 0 20 19 1200 26

Roof 1 22 19 1100 34.5


Air 0 - 19 1200 21.5

Answer. Mean internal gain 48 kW, mean tei 21.2oC, total swing in gains 𝑄𝑡� 399.375 kW, 𝑡𝑒𝚤�

3.3oC, peak environmental temperature tei 24.5oC.

120. Describe, with the aid of sketches, how shading devices and glass types are used to

assist in the provision of thermal comfort within buildings and how they affect the natural

illumination and cooling plant loads.

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121. A window 3 m long and 2 m high is recessed 200 mm from the face of a building. The

wall azimuth is 170o and the solar azimuth at 13.00 h sun time is 190o. Calculate the shade

width on the window.

Answer. 73 mm.

122. A window 3.5 m long and 1.75 m high is recessed 150 mm from the face of the

building. The solar altitude at 15.00 h on 24 August is 37o and the solar azimuth is 240o. The

wall azimuth is 275o. Calculate the unshaded area of the glass.

Answer. 5.473 m2.

123. State the ways in which the shaded areas of buildings can be predicted and the use of

this information.

124. Calculate the net heat transfer through a south facing single glazed window on 21

December at latitude of 51.7oN at noon when the solar irradiance cooling load is 273 W/m2,

the outside air temperature is 5oC and the room resultant temperature is 20oC. The 24 hour

mean outdoor air temperature is 2oC. The window is 2.5m × 2.5m and its thermal

transmittance is 5.7 W/m2 K.

Answer. Net gain of 531 W.

Heat transfer

125. Which are correct about heat transfer?

1. Latent heat transfer changes the dry bulb temperature of air.

2. Latent heat transfer does not affect the dry bulb temperature of air.

3. Latent heat transfer occurs when a mass of water is evaporated into air.

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4. Latent heat transfer means it cannot be measured with a thermometer.

5. Latent heat transfer is an imaginary concept.

126. Which are correct about heat transfer?

1. Sensible heat transfer stands for it making common sense.

2. Sensible heat transfer is rare.

3. Most heat transfers are of the sensible category.

4. Sensible heat transfer takes place from a higher temperature to a lower temperature.

5. Sensible and latent heat transfers tend to cancel each other out.

127. Radiation heat transfer:

1. Uses a formula including the number 5.67 × 10−8.

2. Does not include the emissivity of emitting or receiving surfaces.

3. Ignores the surface area of the emitting surface.

4. Uses absolute temperatures.

5. Calculates the heat transferred in kilojoules.

128. Radiation heat transfer:

1. Only occurs between closely spaced flat surfaces.

2. Is from a warmer to a cooler surface.

3. Must have an air space to transfer the radiation across.

4. Cannot be absorbed by anything.

5. Occurs between surfaces that can see each other at any angle and distance.

129. Which of these correctly describes how heat transfers within buildings?

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1. Radiation through the concrete floor.

2. Convection currents within room air.

3. Conduction between the occupants and the surfaces of the building.

4. Conduction through solid building materials.

5. Radiation across a wall cavity when there is aluminium foil faced building paper.

130. Heat transfer:

1. Through a solid material takes place by convection.

2. Aluminium foil reflective sheet is attached to brick or concrete walls to stop radiation.

3. Occupants exchange heat with the building through conduction.

4. Is always towards a higher temperature area.

5. Convection transfers heat across an air space of any size.

131. Heat transfer:

1. Can never be zero.

2. Is not very important in mild climates like the UK’s.

3. Radiation always takes place across an air space.

4. There is never any radiation exchange between parallel aluminium foil surfaces either

side of an air space in a building structure.

5. Clothing stops people losing heat to the environment.

132. Heat transfer:

1. Conduction is due to increased molecular excitation.

2. Conduction is due to reduced molecular excitation.

3. Conduction causes molecular flow in the direction of temperature gradient.

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4. Glass in a window acts as an insulator.

5. Glass in a window frame has more thermal insulation than the frame.

133. Heat transfer:

1. Steel framed buildings are better insulated than a concrete framed equivalent.

2. The steel frame of a building acts as a thermal bridge so conduction heat flow bypasses

thermal insulation materials alongside.

3. There is no conduction through insulating materials.

4. Heat conduction always flows outward from a building

5. Heat bridges assist the mechanical cooling system of a building.

134. Heat transfer:

1. Thermal resistance of a glass window is mainly due to the surface air films.

2. Heat flow through walls, floors and roofing only takes place by conduction.

3. Conduction heat flow always flows from a lower to a higher temperature.

4. Convection currents can only travel downwards.

5. Radiation heat transfer is irrelevant for buildings.

135. Heat transfer:

1. Takes place between any two temperatures.

2. Is always instantaneous.

3. Conduction heat flow always flows from a higher to a lower temperature.

4. Convection heat flows are one-dimensional.

5. Convection currents can only move upwards.

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136. Heat transfer:

1. Conduction flows are always in one dimension.

2. Convection flows are always with laminar fluid flow.

3. Conduction flows are three-dimensional.

4. Conduction is always the largest of all types of heat flow from a building.

5. Radiation transfers are always towards people.

137. Which of these statements on heat transfer is incorrect?

1. Convection currents in the air around a person usually removes heat from the body.

2. Convection transfers heat between room air and the internal surfaces of the building.

3. External wind is a convection current.

4. Convection transfers heat from a higher to a lower temperature.

5. Convection transfers heat through a concrete floor to outside air.

138. Which is correct about heat transfer?

1. Radiation heat transfer only occurs in hot countries.

2. Radiation is reduced by installing high emissivity dark surfaces.

3. Glass is opaque to radiation heat flow.

4. Radiation heat transfer is calculated from surface temperatures raised to a power of two.

5. Thermal radiation is proportional to the fourth power of absolute surface temperature.


1. Low temperature hot water 70oC panel radiators do not emit radiant heat.

2. Heated floor cannot radiate heat to other room surfaces as it is too cool.

3. Surfaces must be parallel for heat to be transferred by radiation to each other.

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4. Stefan Boltzmann devised a formula for radiant heat transfer.

5. Stefan Hindenburg devised a formula for radiant heat transfer.


1. Shiny surfaces emit most radiant heat.

2. Brick has emissivity of around 0.2.

3. High emissivity surfaces are good thermal radiators.

4. Low-e glass does not reduce radiation heat loss from a heated room.

5. Radiant heat cannot transfer across the cavity in a wall.


1. Radiation heat transfer is not well understood.

2. Lasers are the same as thermal radiation.

3. Thermal radiation travels in the same direction as a laser.

4. Radiation heat transfer is inversely proportional to the surface areas of the surfaces.

5. People do not radiate heat.

142. Which is incorrect about heat transfer?

1. Sunshine contains radiant heat.

2. Radiation travels in straight paths.

3. Radiation heat transfer travels across a vacuum.

4. Radiation heat transfer travels from the sun to every planet in our planetary system.

5. Radiation is the slowest form of heat transfer.

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1. Evaporation of moisture from the human body is not a form of heat transfer.

2. Evaporation of moisture from the human body is the transfer of water mass to the

surrounding air.

3. The human body can live without evaporation from the skin.

4. Breathing does not cause evaporation heat emission from the body.

5. Clothing is designed to greatly reduce evaporation of moisture from the body.


1. Sweating of the body increases evaporation.

2. Sweating of the body is a combination of metabolic activity, clothing, air temperature

and relative humidity.

3. People do not sweat in hot, dry climates such as in Australia.

4. It is impolite to sweat in the company of others.

5. Sweating only occurs in warm weather.


1. Evaporation heat transfer is proportional to the partial pressure of the surrounding air.

2. Still water surfaces do not evaporate.

3. Water must be heated to at least 60oC to cause evaporation.

4. Only steam boilers evaporate water.

5. Vaporise and evaporate have different meanings.


1. Air is a collection of dry gases.

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2. Air is nearly all nitrogen.

3. Air is a mixture of dry gases and finely divided molecules of water.

4. Evaporation of moisture from people adds temperature to surrounding air.

5. Evaporation cannot be described as latent heat transfer.

Humidity

147. Which is correct about air humidity?

1. Moisture in room air finds its own way out of the building.

2. Moisture gained by room air will always condense somewhere and drain away.

3. Moisture within building air will always condense into liquid at the lowest surface

temperature location.

4. Natural ventilation does not remove moist air from a building.

5. Only mechanical exhaust systems remove moist air from a building.


1. Sources of moisture in a building include people, washing and toilet facilities, animals

and rain ingress.

2. All buildings are watertight.

3. The structure of a building always keeps water and moisture out.

4. Building materials are impervious to moisture transfer.

5. Cracks through structures and gaps around doors and windows never let moisture enter

the building.

149. Which are correct about air humidity?

1. Moisture in room air is not important.

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2. People enjoy humid air conditions.

3. People prefer relative humidity to be within the 40% to 70% range for comfort.

4. Outdoor air can become saturated with moisture during rainfall.

5. Saturated outdoor air is always comfortable.

150. Which are correct about air humidity?

1. Exhaling breath produces latent heat gain to the room air.

2. Moisture evaporation from breathing causes condensation on cold windows.

3. Moist air is unhealthy for humans so we must exhale it.

4. People are the only source of moisture output within an occupied building.

5. All open water surfaces indoors create humidity.


1. Spraying water into room air heats up the room.

2. Evaporating water consumes sensible heat energy.

3. Evaporating water consumes latent heat energy.

4. A room with a relative humidity of 25% feels humid.

5. Every air conditioning system must have a humidifier system.


1. Spraying water into room air lowers the room air dry bulb temperature.

2. A room with a relative humidity of 85% does not feel uncomfortably humid.

3. The UK has a dry atmospheric climate all through the year.

4. Victoria in Australia has a high humidity climate all year.

5. Countries within the tropics always have a dry comfortable atmosphere.

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153. Which does not apply to air humidity?

1. Relative humidity is the most commonly used term, but percentage saturation is

technically correct.

2. A thermo hygrograph continuously measures and draws graphs of room conditions.

3. Human hair is used for humidity sensing.

4. Hygroscopic salt-covered wire cells are used for electronic measurements.

5. Room air humidity is generally considered very important for human comfort.

154. How is relative humidity or percentage saturation measured?

1. Sling psychrometer.

2. Globe and wet bulb thermometers.

3. Psychrometer wet bulb depression and anemometer.

4. Human hair hygrometer and psychrometer.

5. Not a directly measured physical property.

155. What is relative humidity?

1. Air moisture content relative to water.

2. Amount of moisture in air above a base of zero.

3. A ratio.

4. Absolute moisture content of humid air.

5. kg moisture in a kg of dry air.

156. What is air percentage saturation?

1. Water suspended in air relative to same quantity of liquid water.

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4. Same as relative humidity.

5. A ratio.

157. What is air humidity?

1. Undesirable property, removed by ventilation.

2. Unwanted moisture.

3. A cause of discomfort.

4. Finely divided droplets of water in air.

5. Steam from a kettle or cooking.

158. What is humidity in air?

1. Superheated steam at the air dry bulb temperature.

2. Superheated steam at the air wet bulb temperature.

3. Steam at low partial pressure.

4. Contamination in clean air.

5. Wet steam at very low pressure and temperature, mixed in with air, producing wet bulb

depression.

Measuring instruments

159. Sling psychrometer:

1. Is a psychiatrist suspended out of a window.

2. Contains thermocouples.

3. Is a paper and pencil test conducted on job-seekers.

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4. Is an outdated instrument.

5. Has both wet and dry bulb mercury in glass thermometers.

160. Wet bulb thermometer:

1. No such thing.

2. Dry bulb mercury in glass thermometer immersed in a water tank.

3. Does not work in humid air

4. Used inside a 38 mm diameter black copper globe.

5. Mercury in glass thermometer having a wetted cotton sock covering the sensing bulb.

161. Difference between dry and wet bulb thermometer readings:

1. Called the wet bulb depression.

2. Measures room atmosphere depression.

3. Used to find the vapour pressure of the room air.

4. Wet bulb temperature is always higher than the dry bulb temperature due to evaporative

heat transfer.

5. Dry bulb temperature is always higher than the wet bulb temperature due to evaporative

heat transfer.

162. Kata thermometer:

1. Not used any more.

2. Measures Feng Shui Kata factor for a building.

3. Used to measure the cooling effect of room air temperature and velocity.

4. Time taken for the alcohol in the bulb to rise between two marks is taken as the cooling

power of the room air.

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5. Low cost, reliable, calibrated and non-electronic way to assess the cooling power of

room air, but is outdated.

163. An anemometer is:

1. For measuring fan vane angles.

2. For assessing animosity towards the room conditions.

3. A calibrated device to measure air speed in a room, outdoors or an air duct.

4. A rotating vane with thermistor or heated wire sensor.

5. Only be used by qualified personnel.

164. Which is not used for temperature sensing?

1. Heat sensitive pads stuck to surfaces.

2. Mercury in glass thermometers.

3. Copper–constantan thermocouple wires.

4. Thermistor.

5. Lasers.


1. Touching the surface by hand.

2. Microwave emissions and a mobile sensor.

3. Burying a sensors beneath the surface of plaster and concrete.

4. Infra-red non-touch radiation sensing.

5. Clamping thermocouple sensors to pipes.


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1. Aerial scanning from a helicopter, plane or balloon using an infra-red recording camera.

2. Manufacturing industry uses non-touch infra-red scanning on production lines.

3. Satellite scanning images.

4. Infra-red scanning displays where buildings have wasteful hot surfaces.

5. Ultra-violet data loggers.

167. Which is not true about temperature sensing?

1. Is rarely done.

2. Every project has permanent logging.

3. Computer-based building management systems log temperature data.

4. Infra-red scanning finds damaged and leaking thermal insulation.

5. Of great value to the energy auditor.

168. What are needed to aid finding the mean radiant temperature of an enclosure?

1. Kata thermometer.

2. Globe thermometer.

3. Dry and wet bulb thermometers.

4. Surface temperature thermocouples, dry bulb thermometer and a measuring tape.

5. Silvered globe thermometer and anemometer.

169. Which instruments are used to find wind chill index?

1. Kata thermometer.

2. Globe and wet bulb thermometers.

3. Sling psychrometer and anemometer.

4. Thermal comfort meter.

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5. Thermistor anemometer and silvered wet bulb thermometer.

Sick building syndrome

170. What does SBS stand for?

1. Sick building service.

2. Specialised Broadcasting Service.

3. Sports based service.

4. Sick building standard.

5. Sick building syndrome.

171. Where does sick building syndrome apply?

1. Architectural design failures.

2. Perception that exterior design of a building does not fit in successfully with existing

local architecture.

3. Interior of a building that looks to be designed by a sick mind.

4. Polluted interior atmosphere.

5. Poor quality external environment makes users of the building susceptible to airborne

upper respiratory ailments and overall sickness.

172. What does SBS stand for?

1. Stabilised basement substructure.

2. Sick building substitute.

3. Sick building syndrome.

4. Specialised biological standard for a building such as nuclear, biological or chemical

weapons manufacturing facility.

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5. Submarine basic system.

173. Which factors are not included in SBS assessment?

1. Industrial pollution of outdoor air.

2. Tobacco smoke.

3. Too low an occupancy density in a large space.

4. Air bacteria.

5. Noise.


1. Age of the workforce.

2. Volatile vapours in workspace.

3. Lack of rest breaks.

4. Poorly maintained air conditioning system.

5. Inspects and pests.


1. Dampness indoors.

2. Body odour.

3. Polyvinyl chloride vapour.

4. Dust and debris in working environment.

5. Inappropriate but safe clothing for workspace.

176. Which factor is included in SBS assessment?

1. Poorly maintained mechanical equipment.

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2. Time of day.

3. Shift work times.

4. Overbearing management style over workforce.

5. Illegal medication.

177. Which factor is not included in SBS assessment?

1. Inadequately clean working environment.

2. Staff not taking work breaks.

3. Dust in workspace.

4. Lighting glare.

5. Tiredness.

178. Which factor is included in SBS assessment?

1. Staff not taking holiday entitlements.

2. Air handling unit air filters clogged with dirt.

3. Prescribed medication.

4. Government workplace legislation.

5. Excessive working hours.


1. Airborne bacteria.

2. Flickering fluorescent lighting.

3. Boredom.

4. Off gassing from carpets.

5. Fumes from printing inks.

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1. Legionella bacteria from cooling towers.

2. Excessive sunshine on workstation.

3. Inadequate outdoor air ventilation.

4. High indoor air carbon dioxide level.

5. Inability to open windows near to workstation.


1. Legionella bacteria from humidifiers.

2. Lack of windows.

3. Stuffy indoor atmosphere.

4. Legionella bacteria from shower heads and spray taps.

5. Legionella bacteria from standing water surfaces nearby to workstation.


1. Personal medical history or disability.

2. Air temperature, velocity and humidity around workforce.

3. Increased risk from airborne infection due to very young age.

4. Increased risk from airborne infection for the elderly.

5. Increased risk from airborne infection for those suffering bronchitis, asthma or

pneumonia.

183. Which symptom manifests with sick building syndrome?

1. Inability to obtain office space rental clients.

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2. Frequent staff absences and use of medical certificates.

3. Poor return on shareholders’ investments.

4. High energy consumption for the building.

5. Low rental achieved for the building.

184. Which symptom does not manifest with sick building syndrome?

1. Lethargy.

2. Headaches.

3. Excessive alcohol consumption.

4. Aching muscles.

5. Catarrh.

185. Which symptoms manifest with sick building syndrome?

1. Upper respiratory infections.

2. High staff turnover not attributable to commercial factors.

3. Dry eyes.

4. Inability to retain staff in the building.

5. Inability to retain tenants in the building.

186. How is sick building syndrome defined?

1. Many people consider working in the building makes them sick.

2. Publicised condemnation of the building.

3. That combination of health malfunctions that noticeably affect more than 5% of the

building’s population.

4. Accumulation of health malfunctions noticeably affecting 25% of the buildings users.

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5. User formalised surveys finding overall dislike for an inadequately comfortable

environment.

187. Which is a valid means for combating a sick building?

1. Ensure workers take holiday entitlements.

2. Limit working hours to normal contract conditions.

3. Provide easily accessible outdoor rest areas.

4. Eliminate contamination in water systems serving the building.

5. Ensure chlorinated fluorocarbons are not used within the building or in the refrigeration

systems.

188. Which is a valid means for combating a sick building?

1. Provide staff with a gymnasium, canteen and rest room.

2. Remove air conditioning and provide natural ventilation systems.

3. Replace cooling towers with air-cooled condenser water heat exchangers.

4. Treat the air conditioning supply air with deodorant atomiser sprays.

5. Replace complainants with other workers.

189. Which is not a valid means for combating a sick building?

1. Staff training, psychological counselling and repeated surveys.

2. Reduce glare from lighting.

3. Install electronic ballasts for fluorescent lighting to run lamps at 20kHz and eliminate

flicker.

4. Regular replacement of air filters.

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5. Programme of interior air duct cleaning.

Temperature and pressure 190. Dry bulb air temperature is measured by:

1. Thermocouple.

2. Black bulb thermometer.

3. Mercury in glass thermometer.

4. Sling psychrometer.

5. Thermistor anemometer.

191. Air dry bulb temperature is measured by:

1. Suspending a sensor about 1.0 m below the ceiling and waiting for it to stabilise.

2. Reading the building management system computer screen data from a fixed sensor in

the room.

3. Leaving a sling psychrometer on a desk for an hour.

4. Shielding a mercury in glass thermometer from room air draughts.

5. Rotating a sling psychrometer at head height in room air for one minute and taking an

immediate reading.

192. Air dry bulb temperature is dependent upon:

1. People and furniture.

2. Size of room.

3. Radiation sources within the room.

4. Solar heat gain through the windows.

5. Air velocity in the room.

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193. Atmospheric vapour pressure is:

1. The total pressure of the atmosphere at the time.

2. The pressure exerted on the ground by the dry gases of the atmosphere above sea level.

3. The sum of the clouds, wind and static air forces on the ground.

4. That part of the barometric pressure produced by the water vapour in humid air.

5. None of these.

194. Which is not one atmospheric pressure?

1. 300 inches of mercury.

2. 1.0 bar.

3. 14.7 pounds per square inch, psi.

5. 1013.25 millibars, mb.

5. 101325 Pa.

195. Air conditioning engineers consider atmospheric air pressure to consist of which?

1. Polluted air.

2. Vapours, gases and water vapour.

3. Around 800.0 mb from dry gases plus 213.0 mb due to water vapour.

4. Around 700.0 mb from dry clean gases, 200 mb from polluting vapours and dusts plus

113.0 mb due to water vapour.


Terminology

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196. Explain the use of the peak summertime internal environmental temperature in the

analysis of the thermal comfort conditions. Include in your explanation when it is needed to

be calculated, what importance it has to the building owner and the design engineer and what

part it plays in the decisions to be made on the choice of air conditioning system.

197. Explain why thermal admittance, decrement factor, surface factor, structural time lag

and environmental temperature swing are used in preference to thermal transmittance in the

assessment of summer internal conditions.

198. List the advice that can be given to the owner of a building that suffers from summer

overheating. Explain why the use of additional outdoor air mechanical ventilation may be an

unsuitable solution for some applications but correct for some buildings.

199. Draw a graph showing the balance temperature for a building from the following data:

(a) Constant heat gain from the occupants, lights and electrical equipment of 10 kW

(b) Solar gains of 20 kW at an outdoor air temperature of 0oC, 30 kW at 10oC, 50 kW at 20oC

and 70 kW at 30oC

(c) Conduction and ventilation heat loss of 90 kW at 0oC zero at 21oC and a heat gain of 30

kW at 30oC.

Thermal comfort

200. Which is correct about thermal comfort?

1. Elderly sedentary people can develop hyperthermia in winter.

2. Hypothermia is eradicated in the UK due to government policies.

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3. Hypothermia is a temporary condition that is a nuisance but it never affects young

people.

4. Hypothermia is the inevitable lowering of body temperature leading to loss of life.

5. Shivering is a voluntary reflex action when we feel cold.

201. Mean radiant temperature:

1. Can only be calculated from empirical formulae.

2. Explains why some rooms feel like warm sunshine.

3. Measured with a solar energy meter or photovoltaic cell.

4. Measured by a 150 m diameter globe thermometer.

5. Calculated from the room air velocity, globe and dry bulb air temperatures at the point

of measurement.

202. In well-insulated buildings having modest glazing areas and little air movement, which

will operative temperature be closest to?

1. Globe temperature.

2. Mean radiant temperature.

3. Wet bulb temperature.


5. Environmental temperature.

203. Resultant room temperature:

1. Can be equal to operative temperature under some conditions.

2. Explains the resulting effect of all sources of warmth in the space.

3. Means the result of the air conditioning engineer’s design.

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4. Calculated from the room air velocity, globe and dry bulb air temperatures at the point

of measurement.

5. Same as mean radiant temperature.

204. List and discuss the factors affecting thermal comfort.

205. State how extremes of heat and cold affect the workers on a site, what environmental

measurements can be taken, and the corrective actions are possible to ensure safe and healthy

working conditions.

206. Describe with the aid of sketches how each of the following instruments function: dry

bulb thermometer, wet bulb thermometer, globe thermometer, vane anemometer,

thermocouple, thermistor and infra-red scanner.

207. An open plan office is designed for sedentary occupation and is to have general air

movement not exceeding 0.2 m/s and an air temperature of 22°C d.b. in winter. It is expected

that a globe temperature of 20°C would be found at the centre of the room volume. What

would be the, mean radiant, resultant, environmental and operative temperatures?

Answer. 17.9oC, 17.2oC, 19.3oC, 20.3oC.

208. A lecture theatre is designed for sedentary occupation and is to have general air

movement not exceeding 0.5 m/s and an air temperature of 21°C d.b. in winter. It is expected

that a globe temperature of 18°C would be found at the centre of the room volume. What

would be the, mean radiant, resultant, environmental and operative temperatures?

Answer. 13oC, 11.3oC, 15.7oC, 20oC.

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209. A conference room is designed for sedentary occupation and is to have general air

movement not exceeding 0.35 m/s and an air temperature of 24°C d.b. in summer. It is

expected that a globe temperature of 21°C would be found at the centre of the room volume.

What would be the, mean radiant, resultant, environmental and operative temperatures?

Answer. 16.8oC, 15.4oC, 19.2oC, 21.4oC.

210. Survey the factors affecting thermal comfort and explain what they mean.

211. What was the earlier name for operative temperature regarding comfort assessment?

1. Wet resultant temperature.

2. Wet bulb globe temperature.

3. Dry resultant temperature.



212. Fanger’s thermal equation for sedentary comfort:

1. Finds a balance between variables affecting comfort.

2. Shows that people prefer slightly cool conditions.

3. Shows that people prefer slightly warm conditions.

4. Shows that it is impossible to satisfy everyone in the room.

5. Shows when room conditions create thermal neutrality, i.e. neither too hot nor too cool.

213. Which is not correct for evaluation of heat stress index, HSI?

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1. A value of 50 creates some discomfort and mental ability difficulty.

2. A maximum of 165 for a fit young professional athlete of Olympic standard.

3. The range of 40–60 means unsuitable for mental effort.

4. Only selected personnel who are fit enough can work when it is in the range 70–90.

5. 100 is the maximum possible for a fit acclimatised young male.

214. Heat stress index means:

1. The number of days a worker can stay in that environment is found from the allowed

exposure time.

2. Allowed exposure index is the overall effect of heat exposure.

3. Heat stress index divided by the maximum available evaporative cooling gives the

allowed exposure time.

4. The required evaporative cooling divided by the maximum available evaporative

cooling gives the allowed exposure time.

5. When HSI is above 100, the allowed exposure time is calculated.

215. The purpose of erecting a building is to do what?

1. Stop wind blowing papers off desks.

2. Keep people warm or cool.

3. Keep rain off people.

4. Make a statement to society.

5. Filter the external environment.

216. Which is the basic need of human comfort?

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1. Constant core body temperature.

2. Quiet indoor environment.

3. Being comfortably warm.

4. Avoidance of draughts.

5. Avoiding suffering heat stroke by use of cooling systems.

217. What is consumed in maintaining human comfort?

1. Bricks, concrete and glass in buildings.

2. Primary energy.

3. Intellectual capacity in designing air conditioning systems.

4. All of our human technical capabilities.

5. More of the world’s resources than are justifiable.

218. Thermal comfort PPD means?

1. Personal preferences determined.

2. Personal preferences determination.

3. Has no meaning.

4. Percentile people dissatisfied.

5. Predicted percentage of dissatisfied people.

219. Thermal comfort zone is:

1. Where everyone is satisfied.

2. All data falls within one standard deviation of the ideal conditions.

3. Where the predicted mean vote of all occupants falls within the slightly cool to slightly

warm band.

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4. When the environmental temperature is correct for the application.

5. When nobody complains.

220. Thermal comfort zone is:

1. Entirely different for males and females.

2. Conditioned by country and locality of origin.

3. Can never be the same for everyone.

4. Dependent upon body weight, height and shape.

5. Independent of nationality, geographic origin, age, gender and body build.

221. Personal comfort is:

1. Unlikely to be achieved for everyone in a working environment.

2. Achieved by each person adapting their clothing, working location, activity level and

daily habits to cope with the overall indoor environment provided for everyone.

3. Individually sacrificed for the good of all.

4. Not to be an expectation.

5. Too expensive to achieve in the workplace.

222. Cold outdoor climates:

1. Are assessed by frost bite index, FBI.

2. Are assessed by the wind burn factor, WBF.

3. Affect building site workers due to freezing cold high wind speed.

4. Are rated as negative air temperatures.

5. Are assessed by the wind chill index.

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223. Cold outdoor climates:

1. Wind chill index found from local air velocity and dry bulb air temperature.

2. Frost bite occurs at a wind chill index of 900.

3. Frost bite can happen at any negative Celsius air temperature.

4. Frost bite should be avoided if wind chill index, WCI, is less than 1400 at an air

temperature of −10oC d.b. during a 30 minute exposure.

5. Adequate clothing always avoids frost bite.

224. Equivalent wind chill temperature, EWCT:

1. Cannot be measured or found.

2. The same effect of cooling as when running in cold air.

3. Calculated value for the same cooling effect of the measured conditions if the air is at

walking speed.

4. Same as 100 mm diameter globe temperature.

5. Same as resultant temperature.

225. Hot climates:

1. Assessed with globe thermometer.

2. Cannot be analysed satisfactorily.

3. Data must include a solar radiation sensor, solarimeter.

4. Outdoor physical work must cease when outside air dry bulb temperature equals body

temperature.

5. Assessed with heat stress index calculation.

226. Hot climates:

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1. Are easily accommodated by the human body.

2. Can kill people.

3. Are fine as long as humans drink one litre of water an hour.

4. Can lead to inevitable rise of body temperature.

5. Body metabolic rate increases to compensate.

227. Hot climates:

1. Create health and safety at work issues.

2. Require skin covering with loose cotton clothing.

3. Building constructers always work in the shade.

4. Sweating does not air body cooling.

5. People born in hot climates cope easily with hot conditions.

228. Hot climates:

1. Weather never gets too hot for outdoor work in the UK.

2. Coping requires rest, keeping cool and drinking one litre of water each hour.

3. Can cause potentially lethal heat stroke.

4. Heat stroke causes no physical problems.

5. Exertion at work can cause medical problems.

229. Which is not true about heat stroke?

1. Zone of unacceptable rise of body temperature.

2. Body cannot emit sensible heat to a high air temperature.

3. Assessed with wind chill index.

4. Symptoms include fainting, fatigue or vomiting.

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5. Muscles may cramp due to loss of body salts.

230. Normal human body temperature is:

1. 36.0oC.

2. 41.0oC.

3. 37.0oC oral.

4. 35.0oC.

5. Something else.

231. Normal human body temperature is:

1. 101oF.

2. 100oF.

3. 98oF.

4. 98.6oF oral.

5. Something else.

232. Which does not apply to heat stroke in a hot climate?

1. To avoid it, get into a swimming pool.

2. Occurs at a body temperature of 40.6oC.

3. Sweating ceases.

4. Body becomes involuntarily hyperactive.

5. Body becomes comatose, brain damage from reduced blood supply and death is

imminent.

233. Which applies to heat stress index?

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1. It is a perceived scale of 1 to 10 on how hot we feel.

2. It is the inverse of WCI.

3. It is calculated from equivalent outdoor temperature.

4. It is a ratio expressing the measured environment stress against the maximum possible

for a fit young man.

5. Different values for males, females and people’s geographical origin.

234. Which is not true of heat stress index?

1. Involves metabolic rate and calculation of radiative and convective heat transfer from

the person.

2. Sling psychrometer and air velocity meter needed.

3. At maximum possible heat stress, only evaporative cooling is available.

4. Highly trained physically fit athletes and military specialists remain functional at up to a

heat stress index of 180.

5. Atmospheric vapour pressure is needed in the calculations.

235. Which is correct about environmental temperature te?

1. 25% of mean radiant temperature plus 75% of air dry bulb temperature.



4. 75% of mean radiant temperature plus 25% of globe temperature.

5. 25% of globe temperature plus 75% of air dry bulb temperature.

236. Which is correct about resultant temperature tres?

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2. 50% of globe temperature plus 50% of air dry bulb temperature.

3. 40% of mean radiant temperature plus 25% of air dry bulb temperature plus 35% of

globe temperature.

4. 75% of mean radiant temperature plus 25% of globe temperature.


237. Which is correct for indoor comfort conditions in the UK?

1. Comfort temperatures within the range of 15–28oC.

2. Mean radiant temperature always lower than air dry bulb temperature.

3. Creation of a feeling of cosy warmth.

4. Should be fresh and cool.

5. Comfort temperatures within the range of 19–23oC.


1. Should have a feeling of freshness.

2. Slightly cool is preferable to maintain alertness at work.

3. Room air percentage saturation below 60%.

4. Warm breeze at head level from good supply air distribution.

5. Glare control from sunny windows is more critical than air temperature.


1. Large areas of perimeter glazing create a feeling of Feng Shui compatibility with

outdoor environment.

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2. Large areas of perimeter glazing are very comfortable to sit alongside all day when at

work.

3. Lots of solar radiation through office windows leads to happy staff.

4. Air dry bulb temperature and mean radiant temperature should be approximately the

same.

5. Trees alongside office windows always shade sunshine allowing control of mean radiant

and air temperatures.

240. Which is a correct meaning for comfort criteria?

1. 95% of occupants are satisfied with the dry bulb air temperature.

2. Mean radiant temperature just below the air dry bulb temperature in winter.

3. Dry resultant temperature in the range 19–23oC.

4. Dry resultant temperature in the range 24–26oC in summer.

5. Dry bulb air temperature in the range 15–26oC depending upon room application and

season.

241. Which is a correct for comfort criteria?

1. Radiant heating is always preferable.

2. Feeling of freshness rather than hot and oppressive.

3. Mean radiant temperature higher than air temperature is easily achieved with good

design of the heating system in all types of buildings.

4. Mean radiant temperature higher than air temperature is easily achieved within highly

glazed facades of modern buildings.

5. Solar radiation always compensates for lack of radiation from ducted air conditioning

systems.

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1. Air dry bulb temperature must always be higher than mean radiant temperature.

2. Air dry bulb and mean radiant temperatures must always be equal.

3. Mean radiant temperature slightly above dry bulb air temperature is preferable.

4. All-glass atria have a high mean radiant temperature in winter.

5. Solar heat gains to all-glass atria are always beneficial.


1. All-glass atria have a low mean radiant temperature in winter.

2. Highly glazed facades are easily made comfortable by radiant heating systems.

3. Highly glazed facades are always comfortable to sit alongside.

4. Traditional brick walled rooms with small windows in cool climates are no longer

justifiable due to advances in insulated glass technology and knowledge of heat transfer.

5. Highly glazed rooms for sedentary use cannot achieve efficient energy usage.

244. Which is not correct for comfort criteria?

1. High temperature radiant heaters are useful in creating warmth in outdoor covered

areas.

2. High temperature radiant panels installed indoors lose useful heat to the external

environment through the glazing.

3. Low temperature radiant panels installed indoors lose useful heat to the external

environment through the glazing.

4. Radiant heating systems are used to counteract cooling downdraughts created by large

areas of glazing.

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5. Convective heating systems counteract the cooling draughts generated by windows.

245. Which is not correct for comfort criteria?

1. Convective heating upward circulation counteracts cooling downdraughts from large

areas of glazing and roof lights.

2. Natural convector heaters must be located at high level in rooms.

3. Forced convector heat emitters can be located almost anywhere within occupied rooms.

4. Radiant heating panels having a surface temperature of 70oC or more radiate heat to

room occupants.

5. Radiant heating is not safe for close proximity to room occupants, especially children,

the infirm and elderly.

246. Which is a correct statement on percentage saturation for comfort criteria?

1. Below 40% in hot countries or in a gymnasium in the UK to avoid sweaty conditions.

2. Above 70% to reduce static electricity in the air of offices with computer work stations.

3. Above 80% where antique timber furniture is stored to stop wood drying and cracking.

4. Preferably 40% and below in all indoor environments in the UK to minimise

condensation.

5. 40% to 70% for sedentary work in commercial buildings in the UK.

247. Which is the appropriate moving air speed for comfort criteria?

1. 20oC d.b. air should be moving at around 0.1 m/s at neck level.

2. 30oC d.b. air can be moving at 1.25 m/s at head level for sedentary workers.

3. Should be above 2.0 m/s to create a stimulating environment.

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4. Almost stagnant air around sedentary workers is preferable to avoid hot or cold

draughts.

5. Constant air velocity, temperature and direction is preferred so it is predictable for

sedentary workers.

248. Which is appropriate for moving air comfort criteria?

1. Air velocity should be higher at head than feet.

2. Warm and cool draughts are preferable to slow moving air around sedentary workers.

3. Air velocity and direction should vary during sedentary working hours.

4. Local air velocity at seated head level should be 0.2 to 0.5 m/s when moving air is at

22oC d.b.

5. Supply air diffusers should stimulate turbulent eddy currents of 0.15 to 1.5 m/s in the

occupied volume of the room.

249. Which is not an appropriate statement for moving air comfort criteria?

1. Variable air velocity and temperature is preferred.

2. Varying the air velocity during the occupied day is impossible.

3. Varying air velocity during the working day may require the supply air fan to have a

variable speed control.

4. Low energy buildings with natural ventilation systems have air velocity variations due

to changes in prevailing winds.

5. Low energy buildings may have active systems to vary air movement around occupants.

250. How is the sedentary comfort zone determined?

1. Air temperature is always within a band of 18–24oC d.b.

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2. Globe and mean radiant temperature are usually above 25oC.

3. Environmental temperature is at least 23oC.

4. A wide band of combinations of air, mean radiant, resultant and environmental

temperatures encompass the comfort zone.

5. Cannot adequately be measured or specified as personal factors are involved.

251. Environmental temperature:

1. Measures the outdoor environment.

2. No such thing.

3. Is a fictitious number.

4. Combines air dry bulb and mean radiant temperatures in a room.

5. Combines the effect on comfort of air velocity, percentage saturation, radiation and air

conditions in an occupied space.

252. Environmental temperature:

1. Not related to any other temperature scale.

2. Not used anymore.

3. Includes comfort indicators.

4. Related to mean radiant, resultant and air temperatures.

5. Has no connection with room air velocity.

253. Dry resultant temperature:

1. Only applies to dried air.

2. Same as globe temperature.

3. Measured with a 150 mm diameter blackened copper ball suspended in the room.

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4. Measured with a 100 mm diameter blackened copper ball suspended in the room.

5. Cannot be measured by a building management computer system.

254. WBGT stands for:

1. Waste burden globe transfer.

2. Wet bulb ground temperature.

3. Wet bulb gross transfer.

4. Wet bulb globe temperature.

5. Nothing.

255. What is included in WBGT

1. It does not exist.

2. Water basic (demand) and gross (heat) transfers for a building.

3. Wet bulb temperature, globe temperature and dry bulb air temperature.

4. Wet bulb gradient temperature.

5. Wet bulb ground temperature.

256. How is WBGT measured?

1. There is no such thing.

2. It is not a measurable physical property.

3. Calculated from the sum of 70% of the wet bulb temperature, 20% of the 150 mm globe

temperature and10 % of the air dry bulb temperature

(WBGT = 0.7 taoC w.b. + 0.2 tg + 0.1 ta oC d.b.).

4. Calculated from 50% of the air wet bulb temperature plus 50% of the 38 mm diameter

globe temperature.

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5. Calculated from 30% of the air wet bulb temperature plus 40% of the 100 mm diameter

globe temperature plus 30% of the air dry bulb temperature.

257. Which instruments are used to measure WBGT?

1. Sling psychrometer and anemometer.

2. Thermohygrograph and Kata thermometer.

3. 38 mm wet globe thermometer and mercury in glass dry bulb thermometer.

4. 150 mm globe thermometer and sling psychrometer.

5. Wet bulb Kata thermometer, sling psychrometer and anemometer.

258. What is the purpose of finding WBGT?

1. Thermal comfort studies in warm humid climates.

2. Compliance with health and safety at work legislation protecting against heat stress.

3. Validating safety in mine workings.

4. Ensuring outdoor and refrigerated cold room workers are not exposed to cold stress

beyond legislated limits.

5. Academic interest or research.

259. Which of these working environments outdoors may lead to construction worker heat

stress?

1. High radiant heat load, moderate dry bulb temperature and low humidity.

2. Clear blue sky, high air temperature, no shade and low humidity.

3. Clear blue sky, all work conducted beneath solid roofing, moderate air dry bulb

temperature and 90% relative humidity.

4. Clear blue sky, outdoor air 31oC d.b., 18oC w.b., variable warm wind.

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5. Clear blue sky, all work conducted beneath solid roofing, portable cooling fans used to

raise air velocity around worker, outdoor air 41oC d.b and 20% relative humidity.

260. Which of these working environments may lead to construction worker heat stress?

1. High radiant heat load, outdoor work, outdoor air 25oC d.b. and low humidity.

2. Indoor work in confined space, outdoor air 24oC d.b., high humidity and adequate

ventilation.

3. Clear blue sky, outdoor air 35oC d.b., 20oC w.b., little wind, all work conducted in a

deep underground mining tunnel.

4. Clear blue sky, outdoor air 29oC d.b., high humidity, little wind, all work conducted

beneath concrete floor slabs with no perimeter walling.

5. Completely cloudy sky, high air dry bulb temperature, strong wind from inland and high

humidity.

261. Which of these working environments may lead to heat stress?

1. Clear blue sky, outdoor air 41oC d.b., 21oC w.b., strong warm wind, all mechanical

servicing work conducted within a plant room building on the roof of a multi-storey

academic building.

2. Completely cloudy sky, strenuous physical outdoor work, high air dry bulb temperature,

strong wind from inland and high humidity.

3. Clear blue sky, outdoor air 38oC d.b., 22oC w.b., little wind, all work conducted in a

below ground car park.

4. Completely cloudy sky, energy auditor walking throughout an occupied building and

plant rooms, high air dry bulb temperature, strong wind from inland and high humidity.

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5. Clear blue sky, outdoor air 38oC d.b., 20oC w.b., moderate wind, continuous aerobic and

anaerobic exercise within a basement gymnasium for one hour.

262. Human comfort within a building in the UK is provided by what?

1. Fully air conditioning the whole building.

2. Most buildings in the UK provide year-round comfort with heating and natural

ventilation.

3. A combination of low energy building design, natural and mechanical ventilation,

minimal cooling and central heating.

4. Designing buildings with fully glazed exterior walls to catch available solar heat gain.

5. Maintaining air and mean radiant temperatures within acceptable values for each

occupant.

263. Which is the function of the human body thermoregulatory system?

1. Maintains comfort when heat gains to the body exceed its ability to lose heat.

2. Provides alarm signals to prompt appropriate response.

3. Stops blood temperature rising too high.

4. Averages heat gains and losses between extremities to maintain comfort.

5. Attempts to maintain energy balance and maintain 37oC core temperature.

264. The Fanger thermal comfort equation includes the factors:

1. Room size and orientation.

2. Metabolic rate and clothing thermal insulation values.

3. Room air change rate of outdoor air in litre/s m2.

4. Local air velocity and dry bulb air temperature.

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5. Relative humidity.

265. The Fanger thermal comfort equation includes the factors:

1. Aural environment in decibels.

2. Biological effluent loading in olfs.


4. Atmospheric air pressure in millibars.

5. Atmospheric vapour pressure.

266. Thermal comfort variables:

1. Feeling comfortable.

2. Rate at which the body metabolism functions.

3. Oxidation of food to release energy.

4. Physical work being performed by the body.

5. Air dry bulb temperature and percentage saturation.

267. Internal heat production of the human body is around:

1. 5.0 W/m2 while sleeping.

2. 35.0 W/m2 while sleeping.

3. 600.0 W/m2 while working in an office.

4. 110.0 W/m2 while working in an office.

5. 440.0 W/m2 during maximum exertion.

268. Clothing thermal insulation value, clo, is around:

1. 5.0 wearing a swimsuit.

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2. Zero while nude.

3. 1.0 wearing a business suit.

4. 22.0 wearing a sea diving suit.

5. 4.0 wearing an Arctic suit.

269. What is equivalent wind chill temperature measured with?

1. Sling psychrometer and thermistor anemometer.

2. Shielded silvered dry bulb thermometer.

3. 38 mm black globe thermometer and rotating vane anemometer.

4. Cannot be measured, it is a calculated value.

5. Silvered dry bulb thermometer in an enclosure where the wind is slowed to walking

pace.

270. What is used to find equivalent wind chill temperature?

1. Sling psychrometer, thermistor anemometer and a formula.

2. 38 mm black globe thermometer and rotating vane anemometer.

3. Shielded silvered dry bulb thermometer.

4. Thermal comfort meter.

5. Silvered dry bulb thermometer in an enclosure where air speed is static.

271. Which may cause irreversible brain damage and death?

1. Wind chill index above 2400.

2. Frost bite in air below −20oC for 8 hours.

3. Performing work in dry bulb air temperature above 38oC for 4 hours.

4. Heat strain.

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5. Heat stroke.

272. How much should core body temperature be allowed to vary due to hot or cold heat

stress?

1. 1oC.

2. 2oC.

3. 3oC.

4. 4oC.

5. 5oC.

273. An index of heat stress is based on a ratio of heat transfers. Which is it?

1. Allowed exposure time.

2. Wind chill index.

3. Kata cooling power.

4. Dry resultant temperature.

5. Heat stress index.

274. What does EWCT stand for?

1. Air temperature that has the same cooling effect when air velocity is 6.4 km/h.

2. Rate of bodily heat loss due to wind.

3. Cold energy stress on the human body.

4. External wind-cooled thermostat.

5. Outdoor 38 mm black globe temperature.

Thermal insulation

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275. List the ways in which existing residential, commercial and industrial buildings can

have their thermal insulation improved. Discuss the practical measures that are needed to

protect the insulation from deterioration.

276. Review the published journals and find examples of buildings where the existing

thermal insulation has been upgraded. Prepare an illustrated presentation or article on a

comparison of the outcomes from the cases found.

277. Write a technical report on the argument in favour of adding thermal insulation to

existing buildings. Support your case by referring to government encouragement, global

energy resources, atmospheric pollution, legislation, cost to the building user and the

profitability of the user’s company.

278. A flat roof over a bedroom causes intermittent condensation during sub-zero outdoor air

temperatures. The roof has normal exposure. The owners want to eliminate the condensation

and reduce the thermal transmittance to 0.15 W/m2 K. Thermocouple temperature sensors

were used to assess the average thermal transmittance of the roof structure. On the day of test,

the indoor air, ceiling surface and outdoor air temperatures were 16°C, 11°C and −2°C.

Calculate the existing thermal transmittance of the roof and the thickness of expanded

polystyrene slab that would be needed.

Answer. Rsi 0.1 m2 K/W, Q 50 W, U 2.78 W/m2 K, Rn 6.67 m2 K/W, 221 mm.

279. An external solid brick wall is to be insulated with phenolic foam slabs λ 0.025 W/m K

held onto the exterior brickwork with UPVC hangers. Expanded metal is to be fixed onto the

outside of the foam and then cement rendered to a thickness of 12 mm λ 0.5 W/m K. The wall

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has a sheltered exposure. The intention is to reduce the thermal transmittance to 0.3 W/m2 K.

Thermocouple temperature sensors were used to assess the average thermal transmittance of

the wall prior to the design work. On the day of test, the indoor air, interior wall surface and

outdoor air temperatures were 15°C, 12.7°C and 6°C. Calculate the existing thermal

transmittance of the wall and the thickness of phenolic foam that would be needed. If the

foam is only available in multiple thicknesses of 10 mm, state the thermal transmittance that

will be achieved for the wall. Calculate the internal surface temperature that should be found

on the wall for a day when the indoor and outdoor air temperatures are 18°C and 0°C.

Answer. Rsi 0.12 m2 K/W, Q 19.2 W, 114 mm, 120 mm used, Un 0.29 W/m2 K, 17.4oC.

280. The roof over a car manufacturing area consists of 4 mm profiled aluminium sheet λ 50

W/m K on steel trusses. Wood wool slabs, 25 mm λ 0.1 W/m K, are fitted below the roof

sheets. The roof trusses remain uninsulated as they protrude through the wood wool. The

trusses cause condensation to precipitate onto the vehicle bodies during cold weather. The

roof is to be insulated with polyurethane board λ 0.025 W/m K, which will be secured to the

underside of the roof trusses. The roof has a normal exposure. The intention is to reduce the

thermal transmittance to 0.25 W/m2 K. Thermocouple temperature sensors were used to assess

the average thermal transmittance of the roof prior to the insulation. On the day of test the

indoor air under the roof was 13°C, internal roof surface temperature was 11°C and the

outdoor air temperature was 2°C. Calculate the existing thermal transmittance of the roof and

the thickness of polyurethane that would be needed. The insulation is only available in

multiple thicknesses of 10 mm. State the thermal transmittance that will be achieved for the

roof. Calculate the internal surface temperature that should be found on the newly insulated

roof for a day when the indoor and outdoor air temperatures are 16°C and −5°C.

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Answer. Rsi 0.1 m2 K/W, Q 20 W, U 1.82 W/m2 K, extra Ra 0.18 m2 K/W; 81.75 mm, 90 mm

used, Un 0.23 W/m2 K, new Q 4.83 W, 15.5oC.

U values

281. State what is meant by the following terms:

(a) thermal resistance;

(b) thermal conductivity;

(c) thermal resistivity;

(d) specific heat capacity;

(e) thermal transmittance;

(f) orientation and exposure;

(g) surface resistance;

(h) cavity resistance;

(i) emissivity;

(j) admittance factor;

(k) heavyweight and lightweight structures.

282. The following materials are being considered for the internal skin of a cavity wall:

(a) 105 mm brickwork λ 0.62 W/m K;

(b) 200 mm heavyweight concrete block λ 1.63 W/m K;

(c) 150 mm lightweight concrete block λ 0.19 W/m K;

(d) 75 mm expanded polystyrene slab λ 0.035 W/m K;

(e) 100 mm mineral fibre slab λ 0.035 W/m K and 15 mm plasterboard λ 0.16 W/m K;

(f) 40 mm glass fibre slab λ 0.035 W/m K, 150 mm lightweight concrete block λ 0.19

W/m K and 15 mm lightweight plaster λ 0.16 W/m K

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Compare their thermal resistances and comment upon their suitability for a residence.

283. Calculate the thermal transmittances of the following:

(a) 6 mm single glazed window λ 1 W/m K, Rsi 0.13 m2 K/W, severe exposure Rse 0.04

m2 K/W;

(b) 6 mm double glazed window, glass λ 1 W/m K, Rsi 0.13 m2 K/W, Ra 0.18 m2 K/W,

Rse 0.04 m2 K/W;

(c) 220 mm solid brick wall λ 0.84 W/m K and 13 mm lightweight plaster λ 0.16 W/m

K, Rsi 0.13 m2 K/W, Rse 0.04 m2 K/W;

(d) 220 mm solid brick wall λ 0.84 W/m K, 150 mm glass fibre quilt λ 0.035 W/m K and

10 mm plasterboard λ 0.16 W/mK, no cavity Rsi 0.13 m2K/W, Rse 0.04 m2 K/W;

(e) 105 mm brick wall λ 0.84 W/m K, 10 mm air space Ra 0.18 m2 K/W, 40 mm glass

fibre slab λ 0.045 W/m K and 100 mm lightweight concrete block λ 0.19 W/m K, Rsi

0.13 m2 K/W, Rse 0.04 m2 K/W;

(f) 40o pitched roof, 10 mm tile λ 0.84 W/m K, roofing felt λ 0.5 W/m K and 10 mm flat

plaster ceiling λ 0.16 W/m K with 100 mm glass fibre quilt λ 0.04 W/m K laid

between the joists, Ra 0.16 m2 K/W, Rsi 0.1 m2 K/W, Rse 0.04 m2 K/W;

(g) 19 mm asphalt λ 0.5 W/m K flat roof, 13 mm fibreboard λ 0.06 W/m K, 25 mm air

space Ra 0.16 m2 K/W, 100 mm mineral wool quilt λ 0.04 W/m K and 10 mm

plasterboard λ 0.16 W/m K, Rsi 0.1 m2 K/W, Rse 0.04 m2 K/W.

284. A lounge 7 m long × 4m wide × 2.8 m high is maintained at a resultant temperature of

21°C and has 1.5 air changes per hour of outside air at −2°C. There are two double glazed

wood-framed windows of dimensions 2 m × 1.5 m U 3 W/m2 K, and an aluminium framed

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double glazed door of dimensions 1 m × 2 m U 3.6 W/m2 K. Exposure is normal. One long

and one short wall are external and constructed of 105 mm brick, 10 mm air space, 40 mm

polyurethane board, 150 mm lightweight concrete block and 13 mm lightweight plaster. The

internal walls are of 100 mm lightweight concrete block and are plastered. There is a solid

ground floor with edge insulation U 0.34 W/m2 K. Adjacent rooms are at a resultant

temperature of 18°C. Calculate the steady-state heat loss from the room for a convective

heating system. Brick λ 0.84, polyurethane 0.025, lightweight concrete 0.2 and plaster 0.16

W/m. Ra 0.18 m2 K/W, Rsi 0.13 m2 K/W, Rse 0.04 m2 K/W.

Answer. 2330.5 W.

285. A single-storey community building of dimensions 20 m × 15 m × 3 m high has low

temperature hot water radiant panel heaters. There are ten windows of dimensions 2.5 m × 2

m. Natural infiltration amounts to one air change per hour. Internal and external design

temperatures are 20°C and −1°C. Thermal transmittances are walls 0.6, windows 5.3, floor

0.5, roof 0.4 W/m2 K. Calculate the steady-state heat loss.

Answer. 20.112 kW.

286. A single-storey factory is allowed to have 35% of its wall area as single glazing U 5.7

W/m2 K and 20% of its roof area as single glazed roof lights U 5.7 W/m2 K as a design

limitation, while wall and roof U values are not to exceed 0.6 W/m2 K. An architect proposes

a building to meet this standard of dimensions 50 m × 30 m × 4 m high with a wall U value of

0.4 W/m2 K, a roof U value of 0.32 W/m2 K, 20 double glazed windows each of area 16 m2

having a U value of 3.3 W/m2 K and 35 roof lights each of area 10 m2 having a U value of 5.3

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W/m2 K. Does the proposal meet the design restriction and what is the rate of heat loss per m2

floor area?

Answer. Allowed heat loss per degree Celsius difference inside to outside is 3746.8 W/K;

thus the proposal complies. Proposed heat loss 3407 W/K.

287. Calculate the boiler power required for a building with a heat loss of 50 kW and an

indirect hot water storage system for 20 people, each using 50 litre of hot water at 65°C per

day. The cylinder is to be heated from 10°C in 2.5 h. Add 10% for pipe and cylinder heat

losses and 25% for rapid heating from a cold start.

Answer. 83.14 kW.

288. A 30-year-old single-storey building has dimensions 40 m × 20 m × 4 m high with

windows of area 80 m2 and a door of area 9 m2. It is to be maintained at a resultant

temperature of 20°C when the outside is at −1oC and natural ventilation amounts to one air

change per hour. Thermal transmittances are as follows: walls 0.6 W/m2 K; windows 5.3

W/m2 K; door 5 W/m2 K; floor 0.6 W/m2 K; roof 0.8 W/m2 K. A convective heating system is

used. It is proposed to reduce the U values of the windows to 2.6, walls to 0.3 W/m2 K and

roof to 0.32 W/m2 K. Calculate the percentage reduction in heater power that would be

produced.

Answer. 43%.

289. Which of these is correct?

1. Thermal resistivity is the fire resistance property of a material.

2. Thermal resistance is the total resistance to flow of water through a heating system

circulation.

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3. Thermal conductivity is used in calculating the resistance of an electrical heating wiring

system.

4. Thermal resistance is a material component property and is measured in m2 K/W.

5. Thermal resistance is how many hours electrical cable insulation resists fire in the

building.


1. The sheet of glass in a window provides a significant thermal resistance.

2. Thermal conductivity of window glass is around 1 W/m K.

3. Thermal conductivity of window glass is around 1 m K/W.

4. Window glass is only used to keep wind out of the building.

5. Windows create no thermal resistance to heat flow.

291. Which is the correct unit?

1. Thermal conductivity m2 K/W.

2. Thermal transmittance W/m3 K.

3. Thermal conductivity m K/kJ.

4. Thermal resistivity W/m K.

5. Thermal resistivity m K/W.

292. What does ∑𝑈𝐴(𝑡1 − 𝑡2) mean?

1. Something in the Greek language.

2. Universal ASHRAE temperature difference used for building heat gain calculation.

3. Integration of U values and areas during a time interval.

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4. Summation of thermal transmittance, surface area and indoor–outdoor air temperature

difference of each external element of the building.

5. All the U values, surface area and temperature differences added together for the whole

building.

293. Which explanation of thermal conductivity is correct?

1. Ability of a material to conduct electricity.

2. Property evaluating materials’ ability to pass heat.

3. Equal to resistivity multiplied by thickness.

4. Units are W/m3 K.


294. Which is correct about thermal resistance?

1. Calculated from data tables and computer programs.

2. Calculated from material thickness divided by thermal conductivity.

3. Calculated by dividing material thickness in metres by thermal resistivity in m K/W.

4. Units are kJ/m2 K.

5. Units are W/m K.

295. Which of these calculated values of thermal resistance is not correct?

1. 110 mm of brickwork is 0.13.

2. 150 mm of fibreglass roof insulation is 3.75.

3. 100 mm concrete having a thermal conductivity of 2.0 W/m K is 0.05.

4. A metal window frame of 20 mm thickness has a thermal conductivity of 50.0 W/m K

and has a thermal resistance of virtually zero.

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5. A low energy building wall has 1.0 m thickness of phenolic foam having a thermal

conductivity of 0.04 W/m K making a thermal resistance of 25.0 m2 K/W.

296. Which of these calculated values of thermal resistance is not correct?

1. 110 mm of brickwork is 0.13

2. 150 mm of fibreglass roof insulation is 3.75

3. 100 mm concrete having a thermal conductivity of 2.0 W/m K is 0.05

4. A metal window frame of 20 mm thickness has a thermal conductivity of 50.0 W/m K

and has a thermal resistance of virtually zero.

5. A low energy building wall has 1.0 m thickness of phenolic foam having a thermal

conductivity of 0.04 W/m K making a thermal resistance of 25.0 m2 K/W.


1. U value is the sum of all thermal resistivities in a structure.

2. R value is the sum of all thermal resistivities in a structure.

3. Y value is the sum of all thermal resistivities in a structure.

4. U value is the sum of all thermal resistances in a structure.

5. R value is the sum of all thermal resistances in a structure.

298. Which is correct about an existing structure’s thermal transmittance?

1. Can only be calculated from design information.

2. Cannot be measured in situ.

3. Measurement requires a thermal imaging camera.

4. Measures structural temperatures to calculate U value.

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5. Thermocouple temperature sensors have to be buried into drilled holes through the

structure.

Units of measurement

299. What are meant by unity brackets?

1. Something fictitious.

2. I do not understand them.

3. Easily remembered technique for conversion of units.

4. Can only convert millimetres into metres.

5. Cannot be used for real engineering calculations.

300. What do we know about the therm unit?

1. A term describing a vacuum flask.

2. Name of a householder connected to mains gas.

3. The equivalent of 105.5 MJ in heat units.

4. Around 293 MWh.

5. Cannot be compared with metric units.

301. What does GCV stand for?

1. Greater coefficient of volume.

2. Greater calorific value.

3. Great curriculum vitae.

4. Heat released when flue gas water vapour condensation is removed.

5. Gross calorific value of a fuel.

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302. What is specific gravity?

1. Specific and highly grave issue for government.

2. 32.2 ft/s2 or 9.907 m/s2.

3. Relative weight of oil.

4. Specific weight of something.

5. Weight of a fluid relative to the weight of water at 4oC.

303. What are kWs units?

1. A very small amount of energy.

2. Used to measure energy released by atoms during nuclear fission.

3. Used in acoustic measurements.

4. Equal to 1 therm.

5. Equal to 1 kJ, kilojoule.

304. MJ units are equal to which?

1. One large joule.

2. One million kilojoules.

3. 103 kJ.

4. One thousand MWs.

5. 109 J.

305. Which of these is not a correct multiple?

1. kJ = 103 J.

2. MWh = 1000 W × 1 h.

3. 1 GJ = 106 kJ.

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4. 1 mm = 10−3 m.

5. 1 GW = 1000 MW.

Ventilation

306. Which is correct about ventilation?

1. Natural ventilation of buildings is a nuisance.

2. Natural ventilation of occupied buildings does not need to be controlled.

3. Occupiers must always open and close windows to provide natural ventilation.

4. Natural ventilation is an important part of overall building design.

5. Good building design eliminates uncontrolled infiltration of outside air.


1. Exfiltration of air is a bad thing for buildings.

2. Natural ventilation only provides for air to leave the building.

3. All toilet rooms must have natural ventilation openings to outside air.

4. All house bathrooms and toilet rooms must have openable windows to outside.

5. All air leaving a building is replaced by the same quantity of incoming air from outside.


1. Exhaust air from a building is always contaminated.

2. Exhaust air from a building can be recycled to save energy.

3. Only the heat energy of exhaust air can be reused.

4. Exhaust air from a building must always be provided by fans.

5. Every room must have an exhaust air fan.

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309. Which are correct about ventilation?

1. A naturally ventilated house probably has between 0.50 and 3.0 air changes per hour.

2. Less than 1.0 air change per hour may appear to be stagnant air and become odorous.

3. An air conditioned office does not need an outside air supply.

4. Air conditioned commercial buildings may have up to 20.0 air changes per hour.

5. Below ground car parks only need a ducted exhaust air system.

310. Ventilation rates:

1. Are never measured.

2. Designed rates are never achieved due to duct losses.

3. Vary from 4.0 to 25.0 air changes per hour for air conditioned office spaces.

4. Cause drafts.

5. Mean that supply air grilles in office ceilings must direct air away from sedentary

personnel.

311. Outdoor air ventilation rates are around:

1. 50.0 litre/s m2 floor area for normal offices.

2. 5.0 litre/s m2 floor area for normal offices.

3. 0.50 litre/s m2 for normal offices.

4. 50.0 litre/s per person for normal office accommodation with no smoking.

5. 10.0 litre/s per person for normal office accommodation with no smoking.

Ventilation heat demand

312. What does ∑0.33𝑁𝑉(𝑡1 − 𝑡2) mean?

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1. One third of the volumetric air change rate multiplied by daily degree days above base

temperature.

2. 33% of normal building volume per degree temperature difference to calculate energy

usage cost.

3. A design guide to the plant room floor area likely to be required for air handling units.

4. A fraction of the nominal building volume multiplied by air temperature difference.

5. Volumetric specific heat capacity of air, times number of air changes per hour, times

room volume, times indoor–outdoor air temperature difference, calculates natural

ventilation rate of heat loss for a heating system.

World energy resources

313. Which determines energy supply around the world?

1. Each country’s ability to import natural resources.

2. Energy consumption demanded by the population and industry.

3. Selfless sharing of the world’s energy resources.

4. The Kyoto Protocol 1997.

5. International Energy Agency.

314. Which determines energy supply around the world?

1. United Nations World Resources Committee.

2. Military power ensuring supplies to meet need.

3. Atmospheric greenhouse gas international treaties and policies.

4. Political stability of each country having natural hydrocarbon resources.

5. Inter-government contracts.

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4 Psychrometric design

Psychrometric chart

1. Air in a room is at 22oC d.b. and 15oC w.b. Find the conditions from a chart and verify it

from the data tables: percentage saturation, specific volume, dew point, specific enthalpy and

moisture content.

Answer. 46%, 0.846 m3

kg, 10.1oC, 41.7 kJ

kg, 0.0077 kg

kg ).

2. Outdoor air at 0oC d.b. and 100% saturation is heated with a low pressure hot water coil to

30oC d.b. Sketch the psychrometric cycle on a chart and identify all the condition data for

both entry and exit states.

Answer. Entry 0.0038 kgkg

, 9.45 kJkg

, 0.778 m3

kg, 0oC dew point. Exit 30oC d.b., 14.5oC w.b., 14%

saturation, 0.864 m3

kg, 40 kJ

kg, 0oC dew point.

3. Air at 12oC d.b and 20% saturation is heated through an increase of 25 K and then

adiabatically humidified to 90% saturation. Sketch the cycle and identify all the condition

data for the end states.

Answer. Entry 12oC d.b., 4.1oC w.b., 20%, 0.00175 kgkg

, 16.5 kJkg

, 0.81 m3

kg, −9oC dew point.

Heated to 37oC d.b., 15.3oC w.b., 4%, 0.00175 kgkg

, 41.5 kJkg

, 0.881 m3

kg, −9oC dew point.

Humidified 15.8oC d.b., 14.8oC w.b., 90%, 0.0102 kgkg

, 41.5 kJkg

, 0.832 m3

kg, 14.4oC dew point.

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4. Summer outdoor air at 30oC d.b., 21oC w.b. is cooled to 12oC d.b. and 90% saturation.

Sketch the psychrometric cycle and identify all the condition data for the end points.

Answer. Outdoor 43%, 0.00118 kgkg

, 60.3 kJkg

, 0.875 m3

kg, 16.3oC dew point. Cooled 11.1oC w.b.,

0.0079 kgkg

, 32 kJkg

, 10.5oC dew point.

5. Outdoor air at 28oC d.b., 22oC w.b. passes through a direct expansion cooling coil where

the refrigerant evaporates at 5oC. Assume that the air side dew point of the coil is 5oC and that

100% contact factor is maintained. Sketch the psychrometric cycle and identify all the

condition data for the coil air on and air off states. Calculate the reductions in specific

enthalpy and moisture content per kg of air produced.

Answer. Outdoor 58%, 0.0141 kgkg

, 64 kJkg

, 0.872 m3

kg, 19.2oC dew point. Cooled 5oC d.b., 5oC

w.b., 100%, 0.0054 kgkg

, 18.6 kJkg

, 0.794 m3

kg, 5oC dew point. Reductions of 45.4 kJ

kg and 0.0087

kgkg

.

6. Recirculated room air at 21oC d.b., 50% saturation is mixed in equal amounts with summer

outdoor air at 31oC d.b., 22oC w.b. Sketch the mixing process and state the condition of the

mixed air.

Answer. 26oC d.b., 18.6oC w.b., 48%, 0.0103 kgkg

, 52.4 kJkg

, 0.861 m3


7. An air handling unit receives recirculated room air at 23oC d.b., 50% saturation and a flow

rate of 2 m3

s, and fresh air at −5oC d.b., 100% saturation with a flow rate of 0.5 m

3

s. The mixed

air is heated with a low pressure hot water heater coil to 35oC d.b. and then adiabatically

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humidified to 24oC d.b. Sketch the psychrometric cycle, identify each condition point and

calculate the heater coil load in kW.

Answer. Mixed 17.4oC d.b., 13oC w.b., 61%, 0.0076 kgkg

, 36.5 kJkg

, 0.833 m3


Heated 35oC d.b., 19.5oC w.b., 21%, 0.0076 kgkg

, 54.8 kJkg

, 0.883 m3


Humidified 24oC d.b., 19.3oC w.b., 64%, 0.0121 kgkg

, 54.8 kJkg

, 0.858 m3

kg,16.9oC dew point. Duty

54.922 kW.

8. Calculate the heater coil duty when air is heated from 10oC d.b., 8oC w.b. to 40oC d.b.

when the inlet air volume flow rate is 3 m3

s. Use the inlet specific volume to calculate the air

mass flow rate.

Answer. 113.779 kW.

9. A cooling coil has an air inlet condition of 29oC d.b., 21.8oC w.b. and an air outlet state of

13oC d.b., 90% saturation. Sketch the cycle and mark on the sketch all the condition data.

Calculate the cooling duty of the coil when the inlet air flow to the coil is 4 m3

s.

Answer. Inlet 52%, 0.0134 kgkg

, 63.3 kJkg

, 0.874 m3

kg, 18.5oC dew point. Cooled 12.1oC w.b.,

0.0084 kgkg

, 34.4 kJkg

, 0.821 m3

kg, 11.4oC dew point. Duty 132.265 kW.

10. A single duct air conditioning system takes 1.5 m3

s of external air at −3oC d.b., 80%

saturation and mixes it with 5 m3

s of recirculated room air at 20oC d.b., 50% saturation. The

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mixed air is heated to 32oC d.b. prior to being supplied to the rooms. Sketch the cycle and

calculate the heater coil duty.

Answer. 163.5 kW.

11. An air handling unit mixes 0.8 m3/s of fresh air at 32oC d.b., 23oC w.b. with 4 m3

s of

recirculated room air at 22oC d.b., 55% saturation. The mixed air passes through a chilled

water cooling coil whose dew point is 6oC d.b. Incomplete contact between the air and dew

point surfaces causes 10% of the mixed air to bypass the cooling effect. This 10% air flow

mixes with the 90% that contacts the wet surfaces and is cooled to the coil dew point. Sketch

the mixing and cooling process and identify all the data. Calculate the refrigeration capacity

of the cooling coil in kW and ton refrigeration, given that 1 ton refrigeration is 3.517 kW, and

the rate of moisture removal from the air in kg/h.

Answer. Mixed 23.7oC d.b., 0.010 kgkg

, 55%, 17.5oC w.b., 49.5 kJkg

. Cooled 7.8oC d.b., 0.0063

kgkg

, 95%, 7.4oC w.b., 23.7 kJkg

. Duty 145 kW, 41.232 ton refrigeration, condensate 74.867 kg/h.

12. Outside air at −5oC d.b., 80% saturation enters a preheater coil and leaves at 24oC d.b.

The fresh air inlet volume flow rate is 2 m3

s. Find the outdoor air wet bulb temperature and

specific volume, the heated air moisture content and percentage saturation. Calculate the

heater coil duty.

Answer. −5.9oC w.b., 0.7615 m3

kg, 0.00198 kg

kg, 10%, 76.428 kW.

13. A cooling coil has chilled water passing through it at a mean temperature of 10oC. An

air flow of 1.5 m3

s at 28oC d.b., 23oC w.b. enters the coil and leaves at 15oC d.b. Find the

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leaving air wet bulb temperature and percentage saturation. Calculate the refrigeration

capacity of the coil.

Answer. 14.2oC w.b., 91% saturation, 48.055 kW.

14. 2 m3

s of air that has been recirculated from an air conditioned room, is at 22oC d.b., 50%

saturation. It is mixed with 0.5 m3

s of fresh air that is at 10oC d.b., 6oC w.b. Calculate the dry

bulb air temperature and moisture content of the mixed air. Plot the process on a

psychrometric chart and read the specific enthalpy, specific volume and wet bulb temperature

of the mixed air.

Answer. 19.6oC d.b., 0.0075 kgkg

, 38.7 kJkg

, 0.839 m3

kg, 13.9oC w.b.

15. The cooling coil of a packaged air conditioner in a hotel bedroom has refrigerant in it at

a temperature of 16oC. Room air at 31oC d.b., 40% saturation enters the coil and leaves at

20oC d.b. at a flow rate of 0.5 m3

s. Is the air dehumidified by the conditioner? Find the room

air wet bulb temperature and specific volume. Calculate the total cooling load in the room.

Answer. No, 21.2oC w.b., 0.877 m3

kg, 6.681 kW.

16. Air in an occupied room is measured to be 24oC d.b. and 16oC w.b. with a sling

psychrometer. Calculate the following physical properties and verify them from CIBSE tables

and the psychrometric chart, commenting upon any differences found: saturation vapour

pressure, saturation moisture content, vapour pressure, moisture content, percentage

saturation, specific volume, density, specific enthalpy, dew point.

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Answer. ps 2.9808 kPa, gs 0.01885 kgkg

, for tsl 16oC ps 1.8159 kPa, pv 1.276 kPa, g 0.00793 kgkg

,

PS 42 %, h 44.3 kJkg

, pv 1276 Pa, v 0.8523 m3 per kg dry air, density 1.173 kgm3 , tdp 11.03oC.

Accuracy is acceptable for most purposes.

17. Outdoor air is at 1oC d.b. and 0.5oC w.b. Calculate the physical properties of the air and

verify them from CIBSE tables, psychrometric chart and an App.


, for tsl 0.5oC ps 0.633 kPa, pv 0.6 kPa, g 0.0037 kgkg

, PS

91%, h 10.26 kJkg

, v 0.781 m3 per kg dry air, density 1.28 kgm3 , tdp −0.01oC.

18. Outdoor air is at 32oC d.b. and 22oC w.b. Calculate the physical properties of the air and

verify them from all the reference sources.


, for tsl 22oC ps 2.641 kPa, pv 1.966 kPa, g 0.0123 kgkg

, PS

40%, h 63.65 kJkg

, v 0.881 m3 per kg dry air, density 1.135 kgm3, tdp 17.3oC.

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5 System design

Air conditioning systems

1. Which is not correct about the single duct air conditioning system?

1. Used for most applications.

2. Suitable for large single zones.

3. Adaptable for large multi-room buildings.

4. Least efficient type of system.

5. Terminal heating coils may be used in multi-zone applications.

2. Which is correct about a VAV air conditioning system?

1. Stands for valve authority value.

2. Only used in hotels and conference centres.

3. Reducing room demand for cooling opens the VAV damper.

4. Rise in zone air temperature causes the VAV damper to throttle the cool supply air flow

further.

5. Single duct all-air system with a throttling damper at each room supply air outlet.


1. Stands for virtual aerodynamic valve.

2. An outdated system.

3. Air volume control damper in terminal room unit provides correct cooling supply air

flow rate.

4. Not used in multi-zone applications.

5. Throttling damper within office ceiling creates air rush noise.

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1. Setting a minimum supply air flow rate at each terminal unit avoids dumping cool air

onto occupants.

2. Always requires terminal reheat coil.

3. Stands for vortices activated valve.

4. Stands for volume activated variable flow system.

5. One terminal unit serves two zone orientations.

5. Which is a correct description of the dual duct air conditioning system?

1. Duplicated supply and return air ducts.

2. A reduced cost design.

3. Simultaneous heating and cooling to adjacent rooms.

4. Not used in commercial office buildings.

5. Appropriate for low energy new buildings.


1. Always used where close control of zone air humidity is required.

2. Hot and cold supply air streams mixed prior to supply into the air conditioned zone.

3. Low installation cost.

4. Economical operating energy usage.

5. Particularly appropriate to hospital applications.

7. Which is a correct description of the induction unit air conditioning system?

1. Primary air jets induce room air to circulate through a heating or cooling coil.

2. Direct alternative to the dual duct system.

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3. Preferable to the variable air volume system.

4. Not used in multi-room applications.

5. Easily maintained in a clean and healthy condition.

8. Which is a correct description of the induction unit air conditioning system?

1. Each room terminal unit has a secondary air circulation fan.

2. Recirculation air is induced away from the air discharged to atmosphere by suction from

the supply air fan.

3. Recirculated room air is neither heated nor cooled.

4. Each terminal induction unit has a two-, three- or four-pipe heating and chilled water

distribution.

5. Recirculated room air does not need filtration.

9. What does FCU air conditioning system stand for?

1. Full conditioning unit.

2. Face console unit.

3. Full compressor unit.

4. Fan coil unit.

5. Failed compressor unit.

10. Which is a correct description of the fan coil unit air conditioning system?

1. Terminal unit used in an induction system.

2. An FCU is a small AHU.

3. Anything having a fan.

4. Room air conditioner with a fan.

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5. Electric heating coil with a supply air fan.

11. Which is appropriate for an FCU?

1. Can be around the size of a suitcase.

2. Does not always contain a fan.

3. The unit that takes heated and cooled streams of air from different ducts, mixes them

and supplies conditioned air into the zone.

4. Potential direct replacement for an induction unit.

5. Always large enough to walk around inside it.

12. Which is appropriate for an FCU system?

1. Does not require distribution air ducts.

2. Self-contained air conditioning unit.

3. Only requires an outside air duct and electrical power connection.

4. A cooling only terminal unit.

5. Usually has air ducts, chilled water, hot water flow and return plus condensate drain to

sewer pipework.


1. Provides air conditioning to a large single zone such as a lecture theatre.

2. Provides air conditioning in each zone of a multi-zone system.

3. Fan noise is obtrusive for quiet office environments.

4. Usually installed within the floor space.

5. Needs no maintenance.

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1. Installed within ceiling spaces.

2. Does not handle recirculated room air.

3. Has no air filter.

4. Requires no BMS control connection.

5. Incorporated duct silencer.

15. Which is not correct for an FCU system?

1. Each FCU has a ducted outside air connection.

2. 240 volt power supply not needed.

3. Ceiling access panel to control valves, control module and air filter needed.

4. Noise level selected to be appropriate to application.

5. FCU hung from steel rods bolted to concrete or steel floor beams.


1. Terminal unit has no pipe connections.

2. Heating always from electrical resistance coil.

3. Built-in refrigeration compressor provides cooling.

4. Is a decentralised air conditioning system having no central plant.

5. Each FCU usually has hot and chilled water flow and return pipe connections.


1. Around 75% of the supply air from an FCU is recirculated room air.

2. FCU passes the minimum quantity of recirculated room air.

3. FCU passes the maximum quantity of recirculated room air.

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4. Terminal unit has no air filter.

5. Each FCU has a BMS control module.


1. Unit is self-controlled.

2. Unit is manually controlled and adjustable by user.

3. FCU terminal unit has a maintenance access panel suitable for inspection, repair, filter

changing and unit replacement.

4. Fan motor never needs replacing.

5. FCU running always linked to lighting automatic controls.

19. Which of these applies to packaged room air conditioning units?

1. Always connected to a ducted air system.

2. Always connected to a central chilled water plant system.

3. Each unit has a refrigeration compressor.

4. Always very quiet operation.

5. Power demand not exceeding 250 W

20. Which is not correct for packaged room air conditioning units?

1. Small applications such as home single office and motel room.

2. Stand-alone unit used for large computer server rooms.

3. Silent and have no servicing requirement.

4. May be connected to the BMS.

5. Built-in controls.

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Air curtains 21. Why is an air curtain used?

1. Minimises air leakage through an open doorway into and out of an air conditioned,

heated or refrigerated building.

2. To warm the street entrance to a retail premises.

3. To stop street debris blowing into the building.

4. Discourage people standing near doorways.

5. A statement of importance of the building.

22. Which of these is most likely to determine the energy performance of an air curtain?

1. Width and height of the doorway.

2. Radiant heat loss and gain through the doorway opening.

3. Whether the curtain blows horizontally or vertically.

4. Reynolds number of the air flow discharging from the supply slots.

5. Size and location of the return air grilles.

23. Why use an air curtain at doorways when it uses energy to operate?

1. More energy efficient to close the doors.

2. Closed doors must be opened to allow passage so an air curtain improves thermal

comfort, significantly reduces inward flow of unconditioned air and outward air flow of

conditioned air.

3. Status symbol.

4. Keeps entrance area clean.

5. Keeps people traffic moving.

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Air flow measurement

24. What does a pitot-static tube measure?

1. Formula one racing car speed and air velocity in a duct.

2. Nothing, it is just a metal tube.

3. Air static pressure.

4. Total pressure of air at a velocity within a duct.

5. Air velocity pressure.

25. How is a pitot-static tube used?

1. Facing away from air flow direction.

2. Total pressure opening placed at right angles to main airflow direction in a duct.

3. Immersed in water to find static pressure at a depth.

4. Inserted into an air duct facing the airflow.

5. Inserted into a flame to take sample of combustion products into an analyser.

26. How is a pitot-static tube used to measure air velocity?

1. Output from tube converted into air velocity by an anemometer.

2. Difference between total and static air pressure pipes from tube gives velocity pressure

on a manometer. U-tube water gauge or an electronic manometer output reading of

pressure converted into air velocity by formula.

3. Output from pitot-static tube gives total air pressure on a manometer. Manometer output

reading of pressure converted into air velocity by formula.

4. Output from pitot-static tube gives static air pressure on a manometer. Manometer

output reading of pressure converted into air velocity by formula.

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5. Not a currently used method.

Air handling units

27. Which is not part of an air handling unit, AHU?

1. One or two fans.

2. Air ducts.

3. Access for a technician to service all parts.

4. Air intake damper.

5. Heating and cooling coils

28. Which is correct about air filters?

1. Always throw-away type.

2. Only there to stop birds and leaves being sucked into the fan.

3. Remove dust and airborne debris before entry to the occupied spaces of the building.

4. Filter media delaminates and sends harmless particles along ducts.

5. Must be manually inspected to find out when they need replacing.

29. Which is correct about air filters?

1. Always reusable type.

2. Fine mesh filter located close to fan inlet to keep blades and casing clean.

3. Dry fabric air filter not needed where a water spray humidifier is within the AHU.

4. Can be washable, disposable or cleanable filter media.

5. The most common type of filter is the electrostatic precipitator.

30. Which is a feature of recirculated air at an AHU?

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1. Minimised to avoid recirculating dust and vapour pollutants back into the occupied

building.

2. It is an expensive waste of fan energy and duct material.

3. Maximised to take advantage of air that is already at the correct room air temperature.

4. Minimised to avoid CO2 build-up in occupied rooms.

5. Minimised to control cooling and heating energy use.

31. Which is not a feature of recirculated air at an AHU?

1. Saves energy

2. Recirculates humidity, dust and smoke produced in rooms.

3. Biological contamination generated in one room circulates to other rooms.

4. May need a recirculation air fan as well as ductwork.

5. Varied to control room air CO2 and temperature.


1. Minimised to keep the rooms feeling fresh.

2. Maximised to save heating and cooling energy.

3. Remains constant all through the year.

4. Always around 50% of the supply air flow rate.

5. Used to equalise air static pressure in all rooms.


1. Provides low cost cooling during mild weather.

2. Must always be separately filtered from the outside air intake.

3. Always has a run-around pipe coil for heat recovery.

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4. Air flow rate sensor installed in duct to measure and control recirculated flow rate from

BMS.

5. Creates additional noise at the AHU.

34. Which of these statements on air conditioning systems are correct?

1. Air handling units are usually the largest item of plant.

2. Air handling units are always manufactured off-site and delivered in one piece to any

building.

3. Some air handling units are large enough for a person to walk inside.

4. Air handling units are where the room supply air is conditioned.

5. Air handling units do not contain any moving parts.

Chilled beams

35. How is cooling duty of a chilled beam controlled?

1. Motorised damper in ducted air stream controls room air flow through the finned beam.

2. Chilled water flow to each zone controlled by a motorised valve.

3. Chilled water flow switched on/off.

4. Control panel by each workstation allows each person to vary cooling capacity.

5. Chilled water flow rate and temperature for the entire system is modulated in the chiller

plant room according to a schedule of outdoor air temperature,

36. What does a chilled beam mean?

1. Structural steel beam exposed in the occupied room and cooled by a supply air stream

from a directional grille.

2. Refrigerated pipe within a room.

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3. Chilled water pipes alongside structural floor beams.

4. Exposed steel beam at high level in a room having chilled water pipes attached.

5. Natural convector chilled water finned pipe.

37. What can chilled beams achieve?

1. Removes smaller heat gains from occupied spaces.

2. Removes all heat gains from a room.

3. Located above windows to remove perimeter heat gains.

4. Very little, as ducted cooling systems always needed.

5. Only removes heat gains at ceiling level from fluorescent luminaires.

Chilled water system

38. Chilled water for AHUs is supplied at:

1. 19oC.

2. 12oC.

3. 6oC.

4. 70oC.

5. −5oC.

39. AHU chilled water flow control is by?

1. Modulating damper.

2. Electronic control system.

3. Modulating water flow valve.

4. Manually set only once by the commissioning engineer.

5. All valves remain fully open to maximise available cooling during hot weather.

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40. AHU chilled water system has:

1. Three pipes, flow, return and mixed.

2. Direction arrows on pipe insulation.

3. Flow and return pipes.

4. Four pipes so the flow control valve can select heating or chilled water throughout the

year.

5. A single pipe loop system, as cooling coils are all connected in series with each other.

41. Chilled and heating water corrosion control is by:

1. Only using materials that do not corrode.

2. Dripping chemicals into the circulating water continuously.

3. Replacing system water several times a year at servicing intervals.

4. Monthly corrosion inhibitor dosing by a contractor.

5. Monitoring water acidity pH and corrosivity by sensors monitored by the building

management system.

42. Water pumps for chilled, heating and condenser water circulation have:

1. Belt drive from an electric motor.

2. Drive through a gearbox from an electric motor.

3. Direct drive shaft from a 415 volt three phase motor.

4. Direct drive shaft from a 240 volt single phase motor.

5. Normally have a standby pump driven by a diesel engine in the event of power failure.

43. Which water temperature flows through a chilled beam?

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1. 6oC to 12oC.

2. 4oC to 18oC.

3. Below room air dew point.

4. Minimum of room air temperature minus 10oC.

5. Above room air dew point.

Commissioning

44. Which is correct about commissioning air duct systems?

1. Air duct systems do not need to be inspected during commissioning.

2. All air ducts must be internally cleaned prior to commissioning.

3. All air ducts must be internally inspected with remote controlled lamps and cameras

before use.

4. Rough internal projections, rivets and metal cuttings are removed by the commissioning

technician.

5. Air ducts systems are sealed in sections and pressure tested for an airtightness standard

compliance.

Cooling towers

45. Which of these does a cooling tower not do?

1. Rejects heat from the building.

2. Cools condenser cooling water at 35oC when outdoor air is at 40°C d.b.

3. Cools the evaporator circuit.

4. Evaporates condenser water.

5. Only functions when outdoor air wet bulb temperature remains below incoming

condenser cooling water temperature.

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46. Which does a cooling tower do?

1. Always remains completely clean as it is continuously washed with water circulation.

2. Never polluted with airborne contamination.

3. Operates without any energy input.

4. Collects atmospheric dust, debris and bird droppings.

5. Filters the condenser cooling water.

47. Which is not essential for a cooling tower?

1. Continuously dosed with biocide chemicals.

2. Regular draining, physical cleaning and refilling with town water.

3. Uses considerable amounts of fan and pump energy.

4. Daily visual inspection.

5. Free discharge path for vertical plume of humid air above the tower.

48. Which is a primary characteristic of a cooling tower?

1. Quiet operation.

2. Uses almost no water.

3. Potential source of water-based Legionella bacteria for outdoor air.

4. Compact unit usually installed within a chiller plant room.

5. Functions equally well in any outdoor climate.

49. Which statement is correct?

1. A cooling tower cannot be a source of infectious bacteria.

2. A cooling tower rejects heat from the building to the outdoor atmosphere.

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3. Cooling towers are only operational during the summer.

4. Cooling towers spray mains water into the air.

5. Cooling tower water systems are occasionally dosed with biocide.

50. Which of these statements are correct?

1. A cooling tower cannot be a source of infectious bacteria.

2. A cooling tower rejects heat from the building to the outdoor atmosphere.

3. Cooling towers in Victoria are only operational during the summer.

4. Cooling towers have water sprays and a fan.

5. Cooling tower water systems are automatically dosed with biocide.

51. How could a cooling water tower become a health hazard?

1. It cannot while adequately maintained.

2. Very easily, bird droppings may create bacterial growth in cooling water immediately

after monthly servicing work and inspection.

3. Chemical dosing with biocide does not allow any cooling tower water contamination.

4. A cooling tower is outdoors and so is no more a health hazard than an ornamental

fountain.

5. Cooling tower water is always too cool to support growth of bacteria, mould or algae.

52. How could a cooling water outdoor tower become a health hazard?

1. Not possible due to legislated monitoring and maintenance procedures.

2. Outdoor water temperature always remains too cool to support bacteria growth.

3. Cooling tower water is intermittently dosed with biocide chemical so bacteria growth

cannot happen.

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4. Dust storm, bird droppings, leaves, pollen and dust from nearby building sites deposit in

tower and may overcome biocide.

5. Bleed-off water to sewer passes through an air gap and water seal P-trap. Loss of water

seal from evaporation can occur in warm weather while tower remains inactive. Sewer

gases enter tower allowing airborne bacterial infection to spread.

Design calculation

53. An office has a sensible heat gain of 22 kW when the room air temperature is 23oC d.b.

Calculate the necessary volume flow rate of supply air to maintain the room at the design

temperature when the supply air temperature can be 14oC d.b.

Answer. 1.999 m3

s.

54. A lecture theatre is 18 m × 10 m × 4 m. It is maintained at 21oC d.b. and has six air

changes per hour of cooled outdoor air supplied at 16oC d.b. Calculate the maximum cooling

loads that the equipment can meet.

Answer. Q 1.2 m3

s, SH 7.287 kW.

55. A hotel lounge is 15 m × 15 m × 4 m. It is maintained at 22oC d.b. and has nine air

changes per hour of cooled supply air. The cooling plant load is 19 kW. Calculate the

required supply air temperature.

Answer. Q 2.25 m3

s, ts 15.1oC.

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56. An exhibition hall has a winter sensible heat loss of 96 kW when the room air

temperature is 18oC d.b. Calculate the necessary volume flow rate of supply air to maintain

the room at the design temperature when the supply air temperature is 40oC.

Answer. Q 3.891 m3

s.

57. A ducted warm air heating system serves a shop of 30 m × 20 m × 4 m. It is maintained

at 18oC d.b. and has three air changes per hour of recirculated air supplied at 25oC d.b.

Calculate the maximum heat loss from the building that the system can meet.

Answer. Q 2 m3

s, SH 16.49 kW.

58. An open plan office is 30 m × 12 m × 2.8 m. It is maintained at 19oC d.b. and has six air

changes per hour of supply air for both summer and winter. The room heat loss is 27 kW.

Calculate the required supply air temperature.

Answer. Q 1.68 m3

s, ts 33oC.

59. A single duct air conditioning system serves a theatre of 1500 m3 that has a sensible

heat gain of 52 kW and a winter heat loss of 39 kW. It is maintained at 22oC d.b. during

winter and summer. The summer supply air temperature is 14oC d.b. The vapour pressure of

the supply air is 1044 Pa in summer and winter. The supply air fan is fitted upstream of the

heater and cooler coils and operates in an almost constant air temperature that is close to that

of the room air. Calculate the mass flow rate of the supply air in summer, the room air change

rate, the winter supply air temperature and comment upon the volume flow rate under winter

heating conditions.

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Answer. Summer Q 5.315 m3

s, N 12.8𝐴𝐶

h, v 0.822 m

3

kg, m 6.466 kg

s. Winter ts 28.3oC d.b., v

0.863 m3

kg, Q 5.58 m

3

s, recalculated ts 28oC d.b.

60. An office has a sensible heat gain of 16 kW and seven occupants each having a latent

heat output of 50 W when the room air condition is 23oC d.b., 50% saturation. Calculate the

necessary volume flow rate of supply air and its moisture content to maintain the room at the

design state when the supply air temperature can be 14oC d.b. The room air moisture content

is 0.008905kgkg

.

Answer. Q 1.454 m3

s, gs 0.008825 kg

kg.

61. A room has a sensible heat gain of 66 kW and a latent heat gain of 3 kW. The room air

condition is 21oC d.b. and 50% saturation. The supply air temperature is 13oC d.b. Plot the

room and supply conditions and sensible to total heat ratio line on a psychrometric chart.

Answer. 𝑆𝑇 ratio 0.96, Q 6.722 m

3

s, gs 0.007709 kg

kg.

62. Calculate the summer air flows for all the ducts shown on figure 5.4 using the following

data:

Room Volume m3 SH kW Occupants

Office 3500 65 70

Corridor 400 12 6

Toilet 550 3 4

𝑡𝑠 = 14oC d.b.

𝑡𝑟 = 19oC d.b.

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Toilet to have a minimum of six air changes per hour.

OA requirement = 12 lperson s

.

The office and toilet doors each have a grille of free area of 0.25 m2 into the corridor. The

maximum air velocity through the grille is to be 2.75ms

.

Answer. All air flows ls, fresh air inlet 960, total supply 12821, office supply 10630, office

extract duct 9942, corridor supply and extract 1962, toilet supply duct 229, transfer grille into

corridor and toilet 688, toilet separate exhaust 917, plant exhaust 43, plant recirculation duct

11861.

63. A space has sensible heat gains of 60 kW and 3 kW latent. The space condition is 20oC

d.b., 50% saturation. The supply air temperature is 15oC d.b. Calculate the supply air quantity

and moisture content needed.

Answer. 9.846 m3

s, 0.0073 kg

kg.

64. A room 5 m × 12 m × 3 m is to be air conditioned. The maximum sensible heat gain is 7

kW when the latent heat gain is 1 kW. The room condition is to be maintained at 21oC d.b.,

50% saturation by a ventilation rate of eight air changes per hour. Calculate the required

supply air condition.

Answer. Q 0.4 m3

s, ts 7oC d.b., 0.007 kg

kg.

65. A shop has solar heat gains of 8 kW and an internal air condition of 20oC d.b., 50%

saturation. There will be 25 occupants emitting 110 W of sensible heat and 50 W of latent

heat each. There are 2 kW of heat gains from lighting and 1 kW of heat output from

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refrigerated display cabinets. If the supply air can be at 16oC d.b., calculate its quantity and

moisture content.

Answer. SH gain 13.75 kW, Q 2.83 m3

s, 0.00725 kg

kg.

66. An office floor is to have a single duct air conditioning system. Use a psychrometric

chart and the data provided to find the peak summer and winter design loads and air

conditions.

Summer room air 23oC d.b., 50% saturation.

Summer outdoor air 29oC d.b., 22oC w.b.

Winter room air 19oC d.b., 50% saturation.

Winter outdoor air −1oC d.b., −2oC w.b.

Summer supply air temperature 15oC d.b.

Office volume 900 m3.

Glazing area 45 m2.

External wall area 100 m2.

Office has 25 occupants, 90 W sensible, 50 W latent each.

Outside air provision is 12 lperson s

.

There are 12 computers of 180 W.

There is one air change per hour of infiltration by the outdoor air into the office.

The peak cooling load through the west facing glazing is 314 W/m2 at 16.00 h on 21 June.

A solar gain correction factor of 0.48 applies to the reflective glazing.

Ignore heat gains through the structure.

Surrounding rooms are at the same conditions.

Glazing U value is 2.7 Wm2K

.

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External wall U value is 0.6 Wm2K

.

Use the simplest forms of heat gain and loss calculation to obtain approximate plant loads.

Answer. Summer SH gain 12.974 kW, 14.4 Wm3, Q 1.331 m

3

s, N 5.3 air change

h, gr 0.008905 kg

kg, gs

0.008590 kgkg

, fresh air proportion 22.5%, tm 24.4oC d.b., tm 17.8oC w.b., hm 50 kJkg

, 0.856 m3

kg,

supply 15oC d.b., 13oC w.b., cooling coil 20.665 kW. Winter SH loss 9.57 kW, 10.6 Wm3, Q

1.331 m3

s, mixed air tm 14.5oC d.b., gm 0.006 kg

kg, room 45% saturation produced, hm 29.75 kJ

kg,

0.822 m3

kg, supply 25.1oC d.b., 14.7oC w.b., hs 40.55 kJ

kg, heating coil 17.488 kW.

67. A Melbourne hotel has a dual duct air conditioning system. Use a psychrometric chart

and the data provided to find the peak summer and winter design loads, air conditions and

supply air flows from the hot and cold ducts for one room.

Summer room air 22oC d.b., 50% saturation.

Summer outdoor air 39oC d.b., 23oC w.b.

Winter room air 20oC d.b., 50% saturation.

Winter outdoor air 3oC d.b., 2oC w.b.

Summer supply air temperature 16oC d.b.

Air leaves the plant cooling coil in summer at 13oC d.b.

Air leaves the plant heating coil in winter at 25oC d.b.

Glazing area is 12 m2 and external wall area is 30 m2.

Room has two occupants, 90 W sensible, 50 W latent each.

OA provision is 12 lperson s

.

There is no infiltration of outdoor air.

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The peak cooling load through the north facing glazing is 347 W/m2 at noon on 21 January.

A solar gain correction factor of 0.66 applies to the shading.

Ignore heat gains through the structure.

Surrounding rooms are at the same conditions.

Glazing U value is 5.7 Wm2K

.

External wall U value is 0.8 Wm2K

.

Room volume is 150 m3.

Use the simplest forms of heat gain and loss calculation to obtain approximate plant loads.

Answer. Summer SH gain 2.928 kW, 19.5 Wm3, N 9.6 air change

h, total Q 402 l

s where 121 l

s

enters from the hot duct at 23oC and 281 ls is from the cold duct at 13oC, gs 0.008282 kg

kg, fresh

air 6%. Winter ts 23oC d.b., tm 19oC d.b., total supply Q 402 ls comprising 268 l

s, 25oC from

the hot duct plus 134 ls at 19oC from the cold duct.

68. A department store has 340 people in an area of 35 m × 25 m that is 4 m high. Smoking

is permitted.

(a) Calculate the fresh air quantity required to provide 12.5 l/s per person; 4.25 m3/s.

If the air change rate is not to be less than five changes per hour, find the following:

(b) Supply air quantity; 4.86 m3/s.

(c) Percentage fresh air in the supply duct; 87.45%.

(d) Extract air quantity if 85% of the supply air is to be mechanically withdrawn;

4.13 m3/s.

(e) Recirculated air quantity; 0.61 m3/s.

(f) Ducted exhaust air quantity. 3.52 m3/s.

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69. Air enters an office through a 250 mm × 200 mm duct at a velocity of 5 m/s. The room

dimensions are 5 m × 3 m × 3 m. Calculate the room air change rate.

Answer. 20 air changes/h.

70. A lecture theatre has dimensions 15 m × 15 m × 4 m and at peak occupancy in summer

has sensible heat gains of 30 kW and latent heat gains of 3 kW. Room and supply air

temperatures are to be 23°C d.b. and 14°C d.b. respectively. Room air moisture content is to

be maintained at 0.008 kg H2O/kg air. Calculate the supply air volume flow rate, the room air

change rate and the supply air moisture content.

Answer. 2.68 m3/s, 10.72 air changes/h, 0.0076 kg H2O/kg air.

71. To avoid draughts, a minimum supply air temperature of 30°C d.b. is needed for the

heating and ventilation system serving a public room. The room has an air temperature of

21°C d.b. and a sensible heat loss of 18 kW. It is proposed to supply 2 m3/s of air to the room.

Calculate the supply air temperature that is required. If it is not suitable, recommend an

alteration to meet the requirements

Answer. ts 28.6oC d.b., reduce supply air quantity to 1.7 m3/s and use ts, 30oC d.b. if the room

air change rate will not be less than 4 changes/h.

72. A gymnasium of dimensions 20 m × 12 m × 4 m is to be mechanically ventilated. The

maximum occupancy will be 100 people. The supply air for each person is to comprise 20 l/s

of fresh air and 20 l/s of recirculated air. Allowing 10% natural exfiltration, calculate the

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room air change rate, the air flow rate in each duct and the dimensions of the square supply

duct if the limiting air velocity is 8 m/s.

Answer. 15 air changes/h, 710 mm × 710 mm, 2 m3/s fresh air, 2 m3/s recirculated air, 3.6

m3/s extract air, 4 m3/s supply air duct 0.4 m3/s natural exfiltration.

73. An office is 15.0 m × 7.0 m × 2.8 m and has 11.0 air changes per hour from air supplied

through a duct where it flows at a velocity of 8.5 m/s. Which two answers are correct?

1. Supply air flow rate is 1.20 m3/s.

2. Supply air flow rate is 750.0 l/s.


4. Duct dimensions are 325 mm × 325 mm.


74. An open plan workspace is 22.0 m × 10.0 m × 3.5 m and has 15.0 air changes per hour

from air supplied through a duct where it flows at a velocity of 5.0 m/s. Which two answers

are correct?

1. Supply air flow rate is 3208 l/s.



4. Duct dimensions may be 4.0 m × 160 mm.

5. Duct dimensions should be 800 mm × 800 mm.

75. A gymnasium is 25.0 m × 12.0 m × 4.0 m and has 6.0 air changes per hour from air

supplied through a duct where it flows at a velocity of 7.5 m/s. Which two answers are

correct?

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4. Duct dimensions must be 516.4 mm × 516.4 mm.

5. Duct dimensions will be 525 mm × 525 mm.

76. A hotel dining room is 12.0 m × 6.0 m × 3.0 m and has 12.0 air changes per hour from

air supplied through a duct where it flows at a velocity of 4.5 m/s. Which two answers are

correct?






77. A retail shop is 22.0 m × 6.5 m × 3.5 m and has 7.5 air changes per hour from air


correct?






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78. An office is 13.0 m × 5.0 m × 2.85 m and has airflow of 0.75 m3/s from air supplied


1. Room air change rate is 146 per hour.

2. Room air change rate is 0.146 per minute.

3. Room air change rate is 14.6 per hour.



79. An entrance hall is 10.0 m × 4.5 m × 6.5 m and has airflow of 0.975 m3/s from air


correct?


2. Room air change rate is 2.0 per minute.

3. Room air change rate is 288 per 8 hour working day.



80. An industrial workshop is 25.0 m × 12.5 m × 4.5 m and has a heating system airflow of

700 litre/s from air supplied through a duct where it flows at a velocity of 10.0 m/s. Which

two answers are correct?


2. Room air change rate is 1.8 air changes per hour.

3. Room air change rate is 1792 air changes per hour.



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81. A small office of 3.0 m × 4.0 m × 2.8 m has 4.0 air changes per hour from air supplied







82. An atrium 15.0 m × 9.0 m × 12.0 m high has 4.5 air changes per hour from air supplied





4. Duct dimensions could be 2.0 m × 225 mm.

5. Duct dimensions should be 670 mm × 670 mm.

83. A lecture theatre is 18.0 m × 20.0 m × 4.5 m and has 9.5 air changes per hour from air

supplied through a duct where it flows at a velocity of 7.5 m/s. Which three answers are

correct?






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84. A conference hall is 55.0 m × 27.0 m × 3.6 m and has 15.0 air changes per hour from air


correct?






85. A swimming pool hall is 70.0 m × 35.0 m × 5.5 m and has 6.0 air changes per hour

from air supplied through a duct where it flows at a velocity of 12.5 m/s. Which two answers

are correct?






86. A room 3.0 m high has 20.0 air changes per hour from air supplied through a 650 mm ×

500 mm duct where it flows at a velocity of 6.5 m/s. Which two answers are correct?




4. Floor area is 58.5 m2.

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87. Outdoor supply air rate recommended for office ventilation is which value in litre per

second per person?

1. 1.

2. 5.

3. 7.

4. 9.

5. 10.

88. A conference room 5.0 m high has 16.0 air changes per hour from air supplied through

a 1350 mm × 2500 mm duct where it flows at a velocity of 4.5 m/s. Which two answers are

correct?





5. 683.46 m2.

Duct insulation

89. Which is correct about air duct thermal insulation?

1. Air conditioning ducts do not need thermal insulation as heat gains and losses are

minimal.

2. Thermal insulation should be installed within sheet metal air ducts.

3. Return air ducts are always insulated.

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4. Thermal insulation on supply air ducts maintains air condition and should usually be

used.

5. Thermal insulation thickness of 10–15 mm is all that is ever justifiable.

90. Which is true about acoustic insulation of air ductwork?

1. Never needed in a well-designed air conditioning system.

2. Internal lining of air ducts with insulation does not absorb fan noise.

3. Sound waves do not travel inside air conditioning ducts.

4. Fans are never a significant source of duct borne noise.

5. Fans are almost always the source of duct borne noise within an air conditioning

system.

Duct noise

91. Which is correct about noise in air conditioning ducts?

1. Fans are directly bolted to sheet metal ducts to ensure joints do not vibrate free.

2. Fan blade vibration causes noise in air ducts.

3. Dirt accumulation on centrifugal fan blades may cause unbalanced vibration.

4. Fans are the source of noise and vibration in air duct systems.

5. Fan rubber belt drive from the motor isolates the fan from motor vibration.

92. Which is correct about noise in air conditioning ducts?

1. Ducts are mounted on springs to isolate vibration from the building structure.

2. Fan and motor are solidly bolted to a concrete plant base to isolate noise and vibration.

3. Noise from sources within the building cannot enter air ducts and transfer elsewhere.

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4. Fans have a flexible airtight fabric connection with air conditioning ducts to stop

transmission of vibration.

5. Noise created in one room cannot travel through an air conditioning duct and enter

another room.

Fans

93. How is a centrifugal fan driven?

1. Mechanical gearbox from the driving motor.

2. Rubber V or toothed belt.

3. Small pulley on the electric motor shaft and a large pulley on the fan drive shaft.

4. Electric motor directly connected to the fan drive shaft.

5. Chain drive with toothed sprockets.

94. What drives the fan in a large air handling unit?

1. Diesel engine prime mover.

2. Three phase electric motor.

3. Single phase synchronous alternating current motor.

4. 1000 volt AC motor.


95. Discuss the relative merits of centrifugal and axial flow fans used in ventilation systems

for occupied buildings.


1. Gas engine prime mover.

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2. Six-pole phase electric motor.



5. 240 volt AC motor

97. Which is a small fan drive motor, such as in a FCU:

1. DC variable speed motor as they are lowest cost.

2. 415 volt AC motor if they require around 850 W power output.

3. Three phase for any size as this is the most energy efficient type.

4. 240 volt three phase synchronous electric motor.

5. 240 volt single phase direct drive motor.

General knowledge

98. How is room ventilation rate measured?

1. Impossible to measure something that cannot be seen.

2. Can only be calculated from duct air flow rate measurement.

3. Found from releasing a non-toxic tracer gas into the room and measuring its rate of

decay with a katharometer.

4. Measured quantity of tracer gas concentration in room remains constant when

mechanical ventilation is switched off and measured with a thermo anemometer.

5. Tracer gas concentration measured with a carbon dioxide sensor and falls in a straight

line graph when mechanical ventilation is switched off.

99. Which are the two types of heat transfer taking place during ventilation of a building?

1. Latent and radiant.

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2. Sensible and convection.

3. Latent and conduction.

4. Sensible and radiant.

5. Sensible and latent.

100. Show two methods of allowing fresh air to enter a room where extract ventilation is by

mechanical means and the incoming air is not to cause any draughts.

101. Sketch and describe two different types of heating system for each of the following

applications: house, office, commercial garage, shop, warehouse and heavy engineering

factory.

102. Why may the water in large heating systems be pressurised? Explain how pressurisation

systems work.

103. How do heating systems alter the mean radiant temperature of a room? Give examples.

104. What factors are included in the decision on the siting of a heat emitter? Give examples

and illustrate your answer. What safety precautions are taken in buildings occupied by very

young, elderly, infirm or disabled people?

105. How can radiant heating minimise fuel costs while providing comfortable conditions?

Give examples.

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106. Sketch the installation of a ducted warm air heating system in a house and describe its

operation.

107. List the characteristics of electrical heating systems and compare them with other fuel-

based systems.

108. Outline the parameters considered when deciding whether to use a one- or two-pipe

distribution arrangement for a radiator and convector low pressure hot water heating system.

109. How do heating systems keep occupants warm?

1. With conduction heat transfer.

2. By radiating heat directly towards people.

3. By heating the building’s walls and floors.

4. By directly increasing the indoor air temperature.

5. By keeping out cold air in winter.

110. Heating systems keep occupants warm:

1. With conduction heat transfer.

2. By minimising radiation towards bare skin.

3. By heating the building’s walls and floors.

4. By directly increasing the indoor air temperature.

5. By keeping out cold air in winter

111. How are mild steel heating and water service system pipes joined?

1. Grooved or welded pipes with bolted flanges.

2. Compression fittings.

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3. Screwed and socketed.

4. Push-fit collars on those below 25 mm diameter.

5. Welded with no flanges.

112. Recirculating water for heating and cooling systems:

1. Need no corrosion inhibition as dissolved oxygen in water soon dissipates.

2. Must always have galvanised pipes and fittings.

3. Different metals in water systems create electrolytic corrosion.

4. Never have corrosion inhibiting chemicals added.

5. Heat always slows down corrosion.

113. Gas that is vented from a closed hot water circulation system may be:

1. Dissolved oxygen.

2. Air entrained into the systems by the pump.

3. Cavitation air bubbles produced in the pump impeller

4. Methane from oxidation of black steel (could possibly be from 1, 2 and 3 also).

5. Steam.

114. Which are correct about solar heating?

1. Every building is passively solar heated at some time of the year in every country.

2. Sunshine always produces summer overheating in non-air-conditioned buildings in the

UK.

3. Active solar systems only work with natural ventilation.

4. Solar heating systems usually work with thermal storage.

5. Water solar collectors only reach 40oC in a UK summer.

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115. Heat energy is provided on remote country campuses with:

1. Wind generators.

2. Photovoltaic solar cell collectors and battery storage.

3. Liquefied petroleum gas storage tanks and underground pipe distribution.

4. Liquid petroleum product storage tanks.

5. Ground source electrically driven heat pumps.

116. Steam is used in which application?

1. Sterilisation in hospitals.

2. Space heating in large office buildings.

3. Heating coils in air conditioning air handling unit coils.

4. Refrigeration systems.

5. Large campus sites.

117. What is a condensing boiler?

1. Steam boiler.

2. Vapour compression refrigeration.

3. Oil-fired boiler with an exit flue gas temperature of 65oC.

4. Gas-fired water heater producing a flue gas exhaust temperature below 100oC.

5. Gas-fired water heater producing a flue gas exhaust temperature below water vapour

dew point.

118. Why is a condensing boiler different?

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1. Very low thermal efficiency.

2. Flue gas leaves after water vapour condenses.

3. Gas-side heat transfer surfaces run wet.

4. Can only be made of cast iron.

5. Only used in large power stations.

119. A condensing boiler has a higher thermal efficiency because:

1. Made of corrosion resistant materials.

2. Extracts latent heat from flue gas.

3. Can reduce heating system return water temperature lower than in a conventional boiler.

4. Uses fuel having a higher gross calorific value.

5. Reduced water flow rate.

120. How much of an increase in thermal efficiency can be obtained from using a

condensing boiler?

1. 5%.

2. 10%.

3. 15%.

4. 25%.

5. 100%.

121. A gas-fired condensing water heater needs one of the following:

1. Low heating system return water temperature.

2. High heating system return water temperature.

3. Reduced heating system water flow rate.

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4. High heating system water flow rate.

5. Cold water mains connection.

122. Why does a condensing boiler have an induced draught fan?

1. Increased combustion air flow rate required.

2. Additional heat exchanger flue passages create more gas flow resistance.

3. Low temperature flue gas at exit has insufficient buoyancy to create a natural draught

exhaust flow.

4. Blows cool flue gas away from the building.

5. Combustion air inlet duct can be longer.

123. How do condensing boilers withstand acidic corrosion from wet flue gas?

1. All heat transfer surfaces are stainless steel or cast aluminium.

2. Steel heat transfer surface is heat treated and coated.

3. Heat exchanger replaced at five yearly intervals.

4. Carbon fibre laminated stainless steel heat transfer surfaces used in primary and

secondary heat exchangers.

5. Condensation confined within a stainless steel secondary heat exchanger.

124. Which of these is not a correct location for a metal hot water or chilled water radiant

panel?

1. Ceiling perimeter above a window.

2. In the floor.

3. External wall beneath a window.

4. Internal wall facing a window.

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5. Ceiling directly above office workstations.

Ground source heat pumps

125. Which statement on ground source heat pump refrigeration systems is correct?

1. Cannot be used in Australia as the ground is too hot.

2. Must also use outside air for cooling the building.

3. Have a cooling tower.

4. Can be used where enough undeveloped ground is available.

5. The least efficient method of cooling.

Health hazards

126. How can a chilled water cooling coil in an AHU become a health hazard?

1. They cannot, condensation washes the coil clean and drains away, cleaning the coil.

2. They cannot, as upstream air filter does not allow any dust to pass through to the coil.

3. They cannot, as chilled water and surface condensate temperatures always remain

below threshold for Legionella bacteria growth.

4. They cannot, as daily condensation always refills the water seal in the waste trap to the

sewer.

5. Dust passed by air filters accumulates in coil drain tray forming warm moist breeding

ground for bacteria that may pass into air conditioned rooms with air flow.

127. How could a chilled water cooling coil distribute bacteria into occupied air conditioned

rooms?

1. It cannot, as air temperature remains too cool.

2. It will not under normal operation.

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3. Condensate water trap between drain tray and sewer always maintains a water seal.

4. Water seal in P-trap between drain tray and sewer may become dehydrated and allow

sewer gases to pass into the air handling unit and supply duct.

5. It will not when adequately maintained in accordance with codes and standards.

Heat exchangers

128. What does air-to-air passive heat exchanger mean?

1. Duct to recirculate outgoing ventilation air to the outside air intake of an AHU.

2. Actively pumps heat from exhaust air into incoming fresh air.

3. Only used in summer weather to provide free cooling.

4. Only runs in winter to avoid freezing low temperature hot water heating coils.

5. Flat metal plate heat exchanger separating exhaust air stream from incoming outdoor

air.

129. Which is not a feature of an air-to-air passive heat exchanger?

1. Raises incoming winter outdoor air to conditioned room air temperature.

2. Maximum heat transfer efficiency of around 50%.

3. Operates in cross-flow mode.

4. Operates in counter-flow mode.

5. Changes incoming outdoor air by up to around 10oC year-round.

130. Which are correct about air heat recovery units?

1. Transfer outgoing air into incoming air systems in air conditioning systems.

2. Transfer the heat and cooling available from exhaust air into the incoming outside air

supply to an air conditioning system.

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3. Maintain the separation of outgoing and incoming air streams.

4. Need a heat pump to transfer useful heat between air streams.

5. Require frequent cleaning.

131. Which is the most efficient way of recovering energy from room air?

1. Recirculation.

2. Sensible heat recovery thermal wheel.

3. Total heat recovery thermal wheel.

4. Plate heat exchanger.

5. Run-around pipe coils.

132. How does an air-to-air flat plate heat exchanger operate?

1. Flat metal plate is alternatively heated and cooled, transferring heat to incoming cool

outdoor air.

2. Porous flat plate heat exchanger transfers sensible heat from outgoing warm exhaust air.

3. Recoverable heat transfers through an aluminium foil plate between outgoing

conditioned room air and incoming unconditioned outdoor air.

4. Thermal storage bricks are heated by outgoing exhaust air, cooled later in the day by

incoming cool air.

5. Concrete blocks pre-cool incoming outdoor air in daytime hot climates. Heat in blocks

is purged overnight with cool air circulated from within conditioned building.

133. How do heat pipes operate?

1. Useful heat to be recycled passes through hollow pipes.

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2. Sealed evacuated tube has one end warmed by outgoing room air while the other end

warms incoming outdoor cool air.

3. Sealed pipe containing a wick and refrigerant. Refrigerant liquid evaporates and

condenses at opposite ends between outgoing and incoming air streams, recovering

available heat difference.

4. Vacuum tube one metre long evaporates hydrocarbon in the warm air end and

condenses it in the cool air other end, transferring waste heat.

5. Compressed heat transfer fluid in sealed tube transfers heat by conduction and

convection between ends of tube.

134. How does a run-around pipe coil system function?

1. Closed pipe loop passes water by gravity circulation between heat source and sink

locations.

2. Outgoing air duct water cooled coil; closed cycle water pipework; warmed water

pumped through incoming outdoor air duct coil, recovering useful heat.

3. Refrigerated evaporator coil in outgoing waste heat duct passes useful heat to condenser

coil in the incoming air duct.

4. Refrigeration system recovers waste heat in outgoing air with a chilled water coil in

exhaust air duct.

5. Cold water feed pipe to domestic hot water system preheated in an outdoor air coil in

warm weather.

135. Which is the typical thermal efficiency of an air-to-air heat recovery system?

1. Always 100%.

2. 90%.

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3. 85%.

4. 80%.

5. 40% to 85% range.

Heat transfer

136. Which correctly describes heat transfer?

1. Sensible heat transfer comprises all types.

2. Latent heat transfer raises temperature.

3. Sensible heat transfer is logged by a thermocouple and thermistor.

4. Latent heat transfer is hidden from view.

5. Sensible heat transfer only takes place through conduction and convection.

137. Which correctly describes types of heat transfer?

1. Sensible heat transfer is the logical method.

2. Latent heat transfer occurs only in steam.

3. Radiation heat transfer is neither sensible nor latent.

4. Latent heat transfer is easily measured.

5. Sensible heat transfer takes place from an area of higher temperature to one of lower

temperature.

138. Which does not correctly describe heat transfer?

1. Sensible heat is removed from air when water droplets spray into warm air and

vaporise.

2. Latent heat transfer occurs when water is evaporated into steam vapour.

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3. Evaporative coolers and cooling towers rely on latent heat transfer to remove sensible

heat from the water passing through.

4. Evaporative coolers work less efficiently in warm humid climates.

5. Cooling towers already have saturated air, so there is no latent heat transfer with the

circulating water.


1. The sum of sensible and latent heat transfers within the plant determines air

conditioning supply air flow rate.

2. Sensible and latent heat transfer kW values cannot be added together.

3. Air conditioning design supply air flow rate is calculated from the latent heat demand in

the building.

4. Latent heat load requires an increase in supply air flow rate from the AHU.

5. Latent heat transfers do not take place within a refrigerated air conditioning AHU

system.

Hot water heating systems

140. Three rooms have heat losses of 2 kW, 4 kW and 5 kW respectively. Double-panel steel

radiators are to be used on a two-pipe low pressure hot water system having flow and return

temperatures of 85°C and 72°C respectively. Room air temperatures are to be 20°C. Choose

suitable radiators and calculate the water flow rate for each.

141. Sketch and describe a micro bore heating installation serving hot water radiators. State

its advantages over alternative pipework systems.

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142. A medium pressure hot water heating system is designed to provide a heat output of 100

kW with flow and return temperatures of 110°C and 85°C respectively. Calculate the pump

water flow rate required in litres per second.

Answer. 0.95 litre/s.

143. Find the dimensions of a double-panel steel radiator suitable for a room having an air

temperature of 15°C when the water flow and return temperatures are 86°C and 72°C

respectively and the room heat loss is 4.25 kW.

Answer. 2.4 m long × 700 mm high.

144. The two-pipe heating system shown in figure 7.14 is to be installed in an office block

where radiators 1, 2 and 3 represent areas with heat losses of 12 kW, 20 kW and 24 kW

respectively. Water flow and return temperatures are to be 90oC and 75oC respectively. The

pipe lengths shown are to be multiplied by 1.5. Pump A (figure 7.13) is to be used. Pipe heat

losses amount to 10% of room heat losses. The friction loss in the pipes is equivalent to 25%

of the measured length. Find the pipe sizes.

Answer. X 42 mm, Y 35 mm, Z 28 mm, Radiator 1 22 mm, Radiator 2 28 mm.

145. A hot water radiator central heating system is commissioned and tested while the

average outdoor air is 3°C and there is intermittent sunshine and a moderate wind. The

building is sparsely occupied. Water flow and return temperatures at the boiler are 90°C and

80°C respectively and the room average temperature is 27°C. The heating system was

designed to maintain the internal air at 22oC at an external air temperature of −1°C with flow

and return temperatures of 85°C and 73°C respectively. State whether the heating system met

its design specification and what factors influenced the test results.

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Answer. Expected internal temperature 26.5oC, system performance is satisfactory.

How systems work

146. Fan coil air conditioning systems:

1. Have two-, three- or four-pipe hot and chilled water distributions to each room FCU.

2. Are not suitable for use in Australia.

3. Do not need water pipework distributions.

4. Do not need any fans.

5. Require elaborate air filter systems.

147. Single duct air conditioning systems are used:

1. In multi-roomed office and hotel bedroom applications.

2. With hot and chilled water pipe distributions to each fan coil unit.

3. To condition a single large volume occupied space such as a lecture theatre.

4. To service several hospital wards and departments from one air handling unit.

5. To minimise the size and cost of the refrigeration plant.

Nuclear power

148. Which is correct about nuclear sourced conventional power generation?

1. Nuclear power stations never create any greenhouse gases.

2. They will become the sole means of generating electricity.

3. They are too dangerous to build.

4. Spent nuclear fuel rods are safe to handle.

5. Spent nuclear fuel rods remain radioactive for thousands of years.

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149. Which is correct about nuclear sourced conventional power generation?

1. Uranium is combusted to produce steam.

2. Uranium fusion releases heat.

3. Fission of uranium releases heat.

4. Uranium corrodes into lead in releasing heat.

5. Radiation from uranium releases heat.

Observations

150. Here’s a challenge. On a hot sunny day, preferably during a series of them, visit a

variety of buildings where you have permission to enter and write a report on how successful

they are at maintaining indoor air comfort conditions. A suitable range of building types

include a holiday tent, caravan, building site cabin, portable office or beach hut. Compare

brick cavity traditional houses with timber frame with weatherboard homes. Find how

uninsulated metal clad industrial buildings, that is, large tin sheds, cope with hot weather. Are

naturally ventilated brick and concrete built commercial and academic buildings comfortable?

Do stately homes, castles and religious buildings that have stood for hundreds of years

maintain indoor comfort or do they remain cold indoors? Would you be willing to work in a

multi-storey commercial building that does not have air conditioning? Feel free to develop

other locations for assessment and in any country.

151. Study a commercial or academic building that you are familiar with. Sketch and

describe how it is ventilated, heated and cooled. Do the systems perform satisfactorily? Are

you actively involved with controlling the systems? If you were to redesign the HVAC

systems for low energy use in compliance with the HM Government Carbon Plan 2011, what

would you recommend? Write an illustrated report of your recommendations with economic

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justification, CO2 and other greenhouse gas emission reductions and whether such a project

may ever be implemented; if so, when.

152. Explain how solar control is achieved on a west facing window in a warm climate at

a latitudes of 35o south around midday and how and if it may be applied to commercial

buildings in other latitudes. Computer simulation may be popular for such analysis but how

could you physically model shading for design assessment at almost no cost

Psychrometric chart

153. Why is a psychrometric chart used?

1. Personality testing of employees.

2. Psychiatric evaluation process.

3. Plots heat transfers in air conditioning.

4. Tests psychomotor reflex activity.

5. Vapour-compression refrigeration cycle is drawn on it.


1. Shows temperature profile through a wall.

2. Calculates latent heat demand.

3. Calculates sensible heat load on the building.

4. Shows physical properties of humid air.

5. Plots air dry bulb temperature against atmospheric pressure.


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1. Takes data from a sling psychrometer and provides a means of finding percentage

saturation, moisture content and specific enthalpy of humid air.

2. Shows variation of physical properties of dry air with atmospheric pressure.

3. Plots wet bulb temperature against vapour pressure.

4. Shows atmospheric vapour pressure for dry bulb air temperatures from −10oC to 60oC.

5. Plot of air dew point against dry bulb air temperatures.

156. Which is correct for sensible heating processes on a psychrometric chart?

1. Curved line between two dry bulb temperatures.

2. Vertical straight line.

3. Any line at 45o to the horizontal.

4. Horizontal line.

5. A line concentric with the dew point curve.

157. Which of these is a sensible heating process line on a psychrometric chart?

1. Horizontal line representing a move in conditions from right to left.

2. Sloping line downwards from right to left.

3. Horizontal line from left to right.

4. Sloping straight line upwards from left to right.

5. A line following constant percentage saturation from left to right upwards.

158. Which of these is a sensible heating process line on a psychrometric chart?

1. Straight line between two dry bulb temperatures at constant specific enthalpy.

2. Line between two dry bulb temperatures at constant percentage saturation.

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3. Straight line between two dry bulb temperatures at constant moisture content from right

to left.

4. Angled straight line between two dry bulb temperatures from left to right.

5. Straight line between two dry bulb air temperatures at constant moisture content from

left to right.

159. Which of these is a sensible cooling process line on a psychrometric chart?

1. Any curved line from right to left.

2. Horizontal line from right to left.

3. Straight line between two dry bulb air temperatures angled upwards from right to left.

4. Line following constant percentage saturation downwards from right to left between

two wet bulb air temperatures.

5. Vertical line between two specific enthalpies downwards.

160. Which of these does not correctly describe a cooling process line on a psychrometric

chart?

1. Cannot be precisely drawn on the chart due to variation of air percentage saturation

within the air spaces around a cooling and dehumidification coil.

2. Only the end points of the line are known precisely.

3. Line drawn represents overall picture of cooling process through the coil.

4. Curved line downwards from right to left between two moisture contents.

5. Straight line angled downwards between two pairs of coordinates from air dry bulb

temperature and moisture content.

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161. Which of these describes the leaving air condition when warm humid air enters a chilled

water cooling coil?

1. Higher moisture content.

2. Higher specific enthalpy.

3. Same moisture content.

4. Lower dry bulb air temperature and around 90% saturation.

5. 100% saturated air at same moisture content.

162. Which correctly describes cooling processes on a psychrometric chart?

1. Reduces percentage saturation.

2. Reduces air wet bulb temperature.

3. Maintains air at constant specific enthalpy.

4. Maintains constant air wet bulb temperature.

5. Does not change air specific volume.

163. Which correctly describes cooling processes on a psychrometric chart?

1. Lowers air moisture content when cooling medium is at a lower temperature than air

dew point.

2. Leaving air has higher moisture content.

3. Leaving air has same specific enthalpy.

4. Process curve is always in an upwards direction.

5. Cooling coil surface dew point temperature is always above incoming humid air

saturation temperature.

164. Which correctly describes humidification processes on a psychrometric chart?

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1. Increases air dry bulb temperature.

2. Usually reduces air dry bulb temperature.

3. Cannot be drawn on the chart.

4. Air moisture content remains unaltered.

5. Reduces air specific enthalpy.

165. Which does not correctly describe humidification processes on a psychrometric chart?

1. Increases air moisture content.

2. Straight line from left to right angled upwards.

3. Vertical line towards saturation curve.

4. Angled line upwards from right to left towards saturation curve.

5. Adiabatic saturation line.

166. Which does not correctly describe humidification processes on a psychrometric chart?

1. Water sprays onto a chilled water cooling coil.

2. Steam injection provides better air cleanliness.

3. Straight line moving away from 100% percentage saturation curve.

4. Straight line moving towards the 100% percentage saturation curve.

5. Adiabatic saturation line.

Refrigeration

167. Which correctly describes a refrigeration compressor?

1. Uses gas-driven engine producing refrigeration.

2. Car engine adapted for refrigerant gas drives the cooling system.

3. Similar operation to that of an air compressor.

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4. Always has an electrically driven reciprocating gas compressor.

5. Basic operation is refrigerant gas compression.

168. Which applies to vapour-compression refrigeration?

1. Prime mover driven.

2. Centripetal compressor.

3. Refrigerant liquid compressed at 40oC.

4. Refrigerant vapour condensed at 20oC.

5. Electric motor drives a reciprocating piston compressor.


1. Refrigerant gas compressor may be multi-cylinder reciprocating piston or volute scroll.

2. Refrigerant always remains as a gas.

3. Refrigerant R12 is ozone friendly.

4. Refrigerant R22 is in domestic refrigerators.

5. Ammonia is not suitable as a refrigerant.


1. Compressed air.

2. Refrigerant vaporises in the compressor.

3. Screw compressor.

4. Linear compressor.

5. Refrigerant condenses at low pressure and temperature.

171. Which applies to the vapour-compression refrigeration cycle?

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1. Refrigerant liquid is pressurised by a centrifugal compressor.

2. Refrigerant liquid warms the inside of the building.

3. Reciprocating compressor increases refrigerant gas pressure.

4. Refrigerant thermostatic expansion valve stops and starts the flow of refrigerant to the

compressor.

5. Refrigerant liquid evaporates fully at 25oC and 4 bar pressure in the evaporator.

172. Which is not correct about the vapour-compression refrigeration cycle?

1. Refrigerant vapour condenses into liquid at 10 bar.

2. Refrigerant leaves the scroll compressor as superheated vapour.

3. Refrigerant liquid in the evaporator is at above atmospheric pressure.

4. There is no refrigerant liquid in the system while the compressor is running.

5. Refrigerant condenser rejects heat to the outdoor atmosphere at 40oC.

173. What does COP of a refrigeration cooling system mean?

1. Convective operated pressure system.

2. Compressor operated performance.

3. Ratio of heat absorbed by refrigerant divided by power consumption of the compressor.

4. Number is always less than 1.0.

5. Ratio of the heat discharged in the condenser to the input power to the compressor.

174. Which is correct about refrigeration system efficiency?

1. Vapour-compression refrigeration systems have a low energy efficiency and should be

avoided.

2. COP gives little idea of energy efficiency.

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3. COP stands for coefficient of energy performance.

4. Refrigerating effect is always less than the electrical power input to the compressor.

5. COP of a vapour-compression system providing cooling is typically in the range of 6 to

10.

175. Which is a primary characteristic for absorption refrigeration?

1. Absorbs heat from within the building whereas a vapour-compression system cools a

water circulation system.

2. Has an absorption compressor.

3. Uses gas pressure to generate cooling.

4. Requires a source of primary heat energy.

5. Uses no electrical energy.

176. Which describes how absorption refrigeration functions?

1. Operates at constant pressure.

2. Has two heat exchanger drums which operate at well above atmospheric pressure.

3. Does not reject any heat to the outside air.

4. Cannot produce chilled water at 6oC.

5. Two drums that are both at below atmospheric pressure.

177. Which of these is not correct about how absorption refrigeration functions?

1. Coefficient of performance of around 1.0.

2. Utilises waste heat, such as process steam, as its heat energy input.

3. Has boiling, evaporation, condensing, pressure reduction and pumping processes.

4. Can only operate with a gas-fired burner as the source of heat input.

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5. Uses non-toxic refrigerant.

178. Which of these is correct about how absorption refrigeration functions?

1. Only functions with fluorinated hydrocarbon refrigerants.

2. Uses ammonia as a refrigerant.

3. Refrigerant has a high ozone depletion potential.

4. Creates a lot more cooling kW than the consumed input heating power.

5. Water and lithium bromide salt in solution is the refrigerant.

179. Which is not correct in relation to domestic refrigerators?

1. Gas powered refrigerators in homes and caravans are absorption machines.

2. Cool box is the refrigerant evaporator.

3. Air cooled condenser finned heat exchanger is on the back of the refrigerator.

4. Absorption refrigerators have an electrically driven compressor.

5. External fined condenser heat exchanger provides useful heating to the kitchen.

180. Which applies to the lubrication of refrigeration compressors?

1. Reciprocating compressors produce oil carry-over into the refrigerant pipes.

2. Reciprocating compressors do not require lubrication.

3. Compressor lubricating oil never leaves the crankcase.

4. Piston rings do not let crankcase oil pass.

5. Refrigerant lubricates the compressor bearings.

181. What are refrigerants?

1. Combustible hydrocarbons.

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2. Water.

3. Hydrocarbon oil.

4. Toxic.

5. Fluorinated hydrocarbons.

182. Which of these does not apply to refrigerants?

1. Always below atmospheric pressure.

2. Fluorinated hydrocarbons that can be caused to change in physical state.

3. Some are ozone depleting when discharged into the atmosphere

4. Supplied to the refrigerant plant manufacturer and installed in a pressurised liquid state.

5. Fluids that boil at around −30oC at atmospheric pressure.

183. Which of these does not apply to refrigerants?

1. R12 CCl2F2 was commonly used in domestic and small commercial refrigeration.

2. HFC134a hydro fluorocarbon.

3. R22 CHClF2 used in large systems.

4. Supplied in the form of high pressure gas.

5. Operated at 4 to 10 atmospheres pressure within the refrigeration system.

184. Which correctly describes the refrigeration cycle?

1. Compressor increases refrigerant liquid pressure.

2. Condenser is self-cooling.

3. Expansion valve stops and starts the flow of refrigerant.

4. Evaporator absorbs heat from the outside air.

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5. Condenser rejects the heat extracted from within the building to the outside

environment.


1. Condenser absorbs surplus heat from the building.

2. Evaporator rejects heat from the refrigeration system.

3. Compressors of all types must only compress refrigerant vapour.

4. Centrifugal compressors usually pass refrigerant liquid droplets safely.

5. Screw compressors pass a mixture of refrigerant liquid and vapour.


1. Evaporator cools the refrigerant.

2. Liquid refrigerant completely evaporates into superheated vapour at around 5oC in the

evaporator heat exchanger and absorbs heat from the building.

3. Refrigerant does not change its physical state in the evaporator.

4. Refrigerant liquid absorbs only sensible heat from the cooling coil.

5. All refrigerant converts into vapour before entering the evaporator heat exchanger.


1. Thermostatic expansion valve regulates the rate of refrigerant flow into the evaporator

to ensure superheated vapour enters the compressor.

2. Thermostatic expansion valve allows refrigerant liquid to expand.

3. Opening of the thermostatic expansion valve is controlled from a temperature sensor on

the compressor discharge pipe.

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4. Thermostatic expansion valve stops and starts the flow of refrigerant from a digital

controller.

5. TEV is an evaporator isolating valve.

188. Which of these correctly describe a water cooled refrigeration system?

1. Cold vapour leaves the compressor and enters a finned tube heat exchanger with axial

flow cooling fans.

2. Low pressure warm vapour condenses and rejects latent heat to the outside environment

through a shell and tube heat exchanger.

3. Refrigerant vapour condenses at 40oC in an air cooled heat exchanger.

4. Water cooled condenser pump circulates water to a cooling tower.

5. Refrigerant evaporator is a direct expansion cooling coil in an air handling unit.

189. How does a basement 700 kW centrifugal refrigeration compressor normally reject heat

to the outdoor environment in a city centre building?

1. Basement air cooled heat exchanger and ducted outdoor air circulation.

2. Condenser cooling water ejects heat into sewer water through a second heat exchanger.

3. Condenser cooling water passes through multiple plastic pipes buried in soil heat sink.

4. Condenser cooling water circulates between a basement located compressor and a roof

mounted finned tube fluid cooler with several axial fans.

5. Evaporative cooling tower located in basement plant room and ducted to outdoors.

190. Identify which statement correctly describes the operation of the vapour compression

refrigeration cycle:

1. A compressor pump drives liquid refrigerant around the system.

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2. Refrigerant condenses at 20oC to reject heat from the building.

3. Refrigerant gas vaporises at 30oC and at high pressure to absorb heat from the building.

4. An expansion valve raises refrigerant gas pressure

5. Heat is absorbed from the building by vaporising refrigerant at low pressure at around

5oC.

191. What are chlorinated fluorocarbons?

1. Paint solvents.

2. Adhesives used in building services and furnishings.

3. Solvents in cleaning fluids such as R113.

4. Thermal insulation materials.

5. Lubricating oils used in refrigeration and air compressors.

192. What are chlorinated fluorocarbons?

1. Toilet cleaning fluids.

2. Cleaning solvents used on office machines such as photocopiers and printers.

3. Ink-jet and laser printer inks solvents and fixing agents.

4. Personal hygiene deodorants.

5. Foam insulation, packaging filler and furniture padding such as R11.

193. Which is correct about chlorinated fluorocarbons?

1. Released during combustion of timber and plastics.

2. Commonly found in small refrigeration appliances as R12.

3. Can be released into the atmosphere when a refrigeration system is emptied.

4. Toxic.

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5. Flammable.

194. Which is correct about chlorinated fluorocarbons?

1. Must be transferred into a sealed cylinder and sent to recycling or disposal facility.

2. Collected and recycled into usable LPG.

3. Collected and recycled into foam plastic products.

4. Do no harm to the global environment.

5. Collected, liquefied and converted into cleaning solvents.

195. Which is not correct about chlorinated fluorocarbons?

1. R22 commonly used in large refrigeration systems such as chilled water plant.

2. Contained within sealed refrigeration systems at below atmospheric pressure so never

leaks into atmosphere.

3. Used in halon fire extinguishing fluid.

4. Non-toxic.

5. Only exists at atmospheric pressure in gaseous form.

196. What happens to chlorinated fluorocarbons when released into the atmosphere?

1. Dissolved by nearby water and rain.

2. Harmlessly coexist in the atmosphere.

3. Vaporise and dispersed by wind and rain.

4. Degraded by ultra-violet solar radiation releasing chlorine into upper atmosphere that

remains there for many years.

5. Degraded by infra-red solar radiation in the upper atmosphere releasing harmless oxides

of chlorine, carbon and fluorine.

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197. What happens to chlorinated fluorocarbons when released into the atmosphere?

1. Do no known harm.

2. Become diluted within the vast atmosphere forming ice crystals.

3. Release carbon in gaseous form that ought to be recycled as fuel.

4. Degraded by ultra-violet and infra-red solar radiation in the upper atmosphere thus

destroying all its chemical compounds into harmless atoms.

5. Chlorine released into atmosphere, destroys atmospheric ozone, allowing increased

solar radiation onto Earth, expected to cause ecological and human damage.

198. What does ODP stand for?

1. Occupational degradation policy.

2. Oxford demographic population.

3. Ozone depletion potential.

4. Ozone damage problem.

5. Oversupply of damaging products of combustion.

199. Which property should CFC refrigerant replacements have?

1. Flammable.

2. Exist as a fluid at atmospheric pressure.

3. Zero chlorine content.

4. Same environmental properties as CFCs.

5. Identical thermo-physical properties.

200. Which property must CFC refrigerant replacements avoid?

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1. Miscible with compressor lubricant.

2. Chlorine content.

3. Similar specific enthalpy.

4. Zero ODP.

5. Equivalent price.

201. What are fluorinated hydrocarbons used for?

1. Swimming pool water treatment.

2. Biocide decontamination of cooling towers.

3. Ozone-depleting refrigerants.

4. Non-CFC foam insulation and furnishings.

5. Removing CO2 from flue gas.

202. What does CFC stand for?

1. Carbon fibre construction.

2. Carbon fibre cycle.

3. Confederation of fan constructors.

4. Chlorinate fire control.

5. Chlorinated fluorocarbons.

203. Which is the reason to use ice thermal storage in a HVAC refrigeration system?

1. Reduce water chiller plant room space requirement.

2. Reduce number of water chillers needed.

3. Reduce water chiller run time.

4. Install smaller capacity refrigeration compressors.

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5. Reduce energy cost.

204. How can HVAC chiller plant running cost be lowered without reducing cooling

capacity or quality of service?

1. Install phase change ice thermal storage tanks charged during off-peak electrical tariff

times.

2. Reset evaporating temperature to a higher value.

2. Install one large capacity high efficiency water chiller instead of several smaller units.

3. Install several small capacity water chillers and a load control switching program to

optimise plant operation.

5. Reset condensing pressure to a lower value.

205. The average heating, ventilating and air conditioning cooling load during a 10-hour

working day of an office building is 200 kW. Which of these is an appropriate ice thermal

storage chiller capacity when off-peak electricity is available for 7 hours at night?

1. 286 kW.

2. 29 kW.

3. 140 kW.

4. 200 kW

5. Cannot be calculated from this information.

206. How can an off-peak ice making chiller be more efficient to operate than a daytime

water chiller?

1. Greater temperature difference between evaporation and condensing temperatures.

2. Lower outdoor nighttime dry and wet bulb air temperatures.

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3. Reduced electrical tariff.

4. Reduces peak hours electrical demand kW.

5. It is not more energy-efficient.

207. Which if these is not a reason to use ice or chilled water thermal storage for air

conditioning?

1. Reduce greenhouse gas generation.

2. Smaller water chillers.

3. Can use ozone-friendly refrigerant.

4. Reduce total plant room space.

5. Lower capital cost.

208. Which statement best describes how the cooling plant matches its output to the

requirements of the building?

1. Manually determined water chiller running times.

2. Outside weather sensor switches water chillers.

3. Water chiller switching table programmed.

4. Heating system reheats rooms when they are overcooled.

5. Room air thermostats are averaged to switch water chillers.

209. Which of these are used in water chillers for air conditioning systems?

1. Evaporative cooling.

2. Reciprocating compressors.

3. Screw compressors.

4. Ground source heat pumps.

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5. Absorption refrigeration.

210. Describe the operation of the vapour compression refrigeration cycle and sketch a

complete system employing chilled water distribution to cooling coils in an air conditioning

system.

211. Discuss the uses of the absorption refrigeration cycle for refrigerators and air

conditioning systems.

212. Show how refrigeration systems can be used to pump heat from low temperature

sources, such as waste water, outdoor air arid solar collectors, to produce a usable heat

transfer medium for heating or air conditioning systems.

213. Multiple water chillers and water heaters are connected to system pipework:

1. Alongside each other.

2. In series with each other.

3. Independently of each other.

4. In parallel with each other.

5. In any combination of pipes.

214. Which are typical through the wall packaged room air conditioner components?

1. Refrigeration compressor.

2. A building management system control connection.

3. Ducted supply air system.

4. Condenser finned pipe coil.

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5. Fans.

215. Identify which of these statements correctly describe the operation of the vapour

compression refrigeration cycle.

1. A compressor pump drives liquid refrigerant around the system.

2. Refrigerant condenses at 40oC to reject heat from the building.

3. Refrigerant gas vaporises at 30oC and at high pressure to absorb heat from the building.

4. An expansion valve drops refrigerant gas pressure.

5. Heat is absorbed from the building by vaporising refrigerant at low pressure at around

5oC.

216. Which of these statements are correct?

1. A reciprocating refrigeration chiller vibrates and is very noisy.

2. An absorption water chiller consumes a lot of electrical energy and is noisy.

3. Rotary screw and centrifugal refrigerant compressors may be used in large building air

conditioning systems.

4. Refrigeration water chillers are never installed in plant rooms.

5. Most of the electrical energy for an air conditioning system is used by the refrigerant

compressor.

217. Which of these statements on refrigeration systems is correct?

1. Ground source heat pumps cannot be used in Australia as the ground is too hot.

2. Ground source heat pumps must also use outside air for cooling the building.

3. Ground source heat pumps have a cooling tower.

4. Ground source heat pumps can be used where enough undeveloped ground is available.

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5. Ground source heat pumps are the least efficient method of cooling a building.

218. What does VRF mean?

1. Has no meaning.

2. Valuable recycled refrigerant.

3. Variable refrigerant flow.

4. Volume reduced flow.

5. Volume refracted fluorocarbon.

219. What does VRV mean?

1. Variable refrigerant volume.

2. Volume refrigerated valve.

3. Vacuum recycled vanadium.

4. Variable refrigeration value.

5. Valid refrigerant valence.

220. Why use VRF/VRV systems?

1. Lower cost than fixed flow refrigerant systems.

2. Saves having a building management system computer, BMS.

3. No real advantage over alternatives.

4. Bank of outdoor condensing units serve multiple indoor evaporator room air

conditioners.

5. Inverter motor drives are the latest technology and must be used.

221. Why use VRF/VRV systems?

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1. Variable speed drive compressors match cooling and heating demand from multiple

evaporator room units and use less energy than single speed compressors.

2. Not a good idea as inverter drives create additional high frequency noise.

3. Higher cost of inverter driven compressors make system uneconomic.

4. On/off compressor control is more energy efficient.

5. Essential to use latest technology.

222. Which method of controlling the capacity of a refrigeration system offers significant

saving in electrical power?

1. Compressor on/off switching.

2. Compressor cylinder head valve unloading by holding open.

3. Refrigerant hot gas bypass around the compressor.

4. Variable frequency compressor drive.

5. Thermostatic expansion valve refrigerant flow control.

223. Which of these is not a feature of a refrigeration compressor system?

1. Motor thermal overload cut-out switch.

2. Anti-vibration mountings.

3. Compressor discharge line oil separation and return to crankcase.

4. Suction line superheat sensing and capacity control.

5. Acoustic insulation.

224. Which of these is not a type of refrigeration compressor?

1. Scroll.

2. Volute.

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3. Centrifugal.

4. Screw.

5. Piston.

225. When the coefficient of performance during heating, COPH, of a vapour compression

refrigeration cycles is 3.5, which of these is the correct compressor power input to generate

3.5 kW of heating?

1. 3.5 kW.

2. 1 kW.

3. 35 kW.

4. 10 kW.

5. Must be measured.

226. When the coefficient of performance during cooling, COPR, of a vapour compression


2.5 kW of cooling?

1. 2.5 kW.

2. 1 kW.

3. 25 kW.

4. 10 kW.

5. Something else.

227. When the coefficient of performance during heating, COPH, of a vapour compression

refrigeration cycles is 3, which of these is the correct compressor power input to generate 750

kW of heating?

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1. 750 kW.

2. 2250 kW.

3. 100 kW.

4. 250 kW.

5. 75 kW.

228. When the coefficient of performance during cooling, COPR, of a vapour compression


225 kW of cooling?

1. 225 kW.

2. 22.5 kW.

3. 506 kW.

4. 100 kW.

5. 2.25 kW.

Service duct space

229. A four-storey commercial building is to be mechanically ventilated. Air handling plant

is to be sited on the roof. Each floor has dimensions 20 m × 10 m × 3 m and is to have six air

changes per hour. Of the air supplied, 10% is allowed to exfiltrate naturally and the remainder

is extracted to roof level. The supply and extract air ducts run vertically within a concrete

service shaft and the limiting air velocity is 10 m/s. Estimate the dimensions required for the

service shaft. Square ducts are to be used and there is to be at least 150 mm between the duct

and any other surface.

Answer. 1680 mm × 930 mm.

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Supply air condition

230. A banking hall is cooled in summer by an air conditioning system that provides an air

flow rate of 5 m3/s to remove sensible heat gains of 50 kW. Room air temperature is

maintained at 23°C. Derive the formula for calculating the supply air temperature and find its

value.

231. A room has a sensible heat gain of 10 kW and a supply air temperature of 10°C d.b.

Find the supply air rate required to keep the room air down to 20°C d.b.

Answer. 0.793 m3/s.

232. Ten people occupy an office and each produces 50 W of latent heat. The supply air flow

rate is 0.5 m3/s and its temperature is 12°C d.b. If the room is to be maintained at 21°C d.b.

and 50% saturation, calculate the supply air moisture content.

Answer. 0.007469 kg H2O/kg air.

233. The cooling coil of a packaged air conditioner in a hotel bedroom has refrigerant in it at

a temperature of 16°C. Room air enters the coil at 31°C d.b. and 40% saturation and leaves at

20°C d.b. at a rate of 0.5 m3/s.

(a) Is the room air dehumidified by the conditioner? (No)

(b) Find the room air wet bulb temperature and specific volume.

(21.2oC w.b., 0.877 m3/kg)

(c) Calculate the total cooling load in the room. (6.186 kW)

System applications 234. Single duct air conditioning systems are used:

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235. Dual duct air conditioning systems are used:

1. In multi-roomed large office buildings.

2. In hospitals.

3. In hotels.

4. Because they consume the minimum amount of energy of all air conditioning systems.

5. Are the simplest to install and take up least duct distribution space in risers.

236. Which are correct about variable air volume air conditioning systems?

1. Have a terminal unit at the room end of a duct to increase the supply air quantity.

2. Reduce the amount of air supplied to each room due to cooling load variations.

3. Have air handling unit fan speed controllers to maintain a constant supply and

recirculation air duct static air pressures.

4. Are used in multi-room buildings.

5. Are only used to condition large entertainment or hospital operating theatres.

237. Fan coil air conditioning systems:

1. Have two-, three- or four-pipe hot and chilled water distributions to each room FCU.

2. Are not suitable for use in Australia

3. Do not need water pipework distributions.

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4. Do not need any fans.

5. Require elaborate air filter systems.







239. Dual duct air conditioning systems are used:

1. In multi-roomed large office buildings.

2. In hospitals.

3. In hotels.

4. Because they consume the minimum amount of energy of all air conditioning systems.

5. Because they are the simplest to install and take up least duct distribution space in

risers.

240. Variable air volume air conditioning systems:

1. Have a terminal unit at the room end of a duct to increase the supply air quantity.

2. Reduce the amount of air supplied to each room due to cooling load variations.

3. Only operate in summer.

4. Are used in all types of buildings.

5. Are only used to condition large entertainment or hospital operating theatres.

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241. Air handling units contain:

1. Water pump.

2. Direct fired gas burners.

3. Building management system controller.

4. Heating and cooling coils.

5. Cooling tower.

System components

242. Why are motorised dampers fitted into the outside air and return air intakes to the air

handling unit in a large air conditioning system?

1. Close off the air supply during a storm.

2. Stop sucking dust into the building.

3. Vary the winter and summer intake of outdoor air.

4. Shut the air conditioning down at night.

5. Fully open up during fire mode.

243. What connects an air conditioning duct to the supply air grille in the ceiling of an

office?

1. Fan coil unit.

2. Pump.

3. Silencer chamber.

4. Galvanised metal box.

5. Flexible tube.

244. Which of these materials is not used for air ducts?

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1. Copper and stainless steel sheet.

2. Brick, timber and stone.

3. Galvanised sheet steel.

4. Spirally wound flexible airtight fabric.

5. Porous fabric.

245. Which is not correct about air ductwork?

1. Spiral wound flexible fabric ducts make final connections to terminal units and diffuser

boxes.

2. Air ducts have taped joints for air tightness.

3. Air duct leakage is unimportant.

4. Galvanised sheet steel ductwork has riveted or flanged joints.

5. Air ducts can be cleaned internally.

246. What is the meaning of chilled beam?

1. Structural steel beam that is kept cool by the air conditioning system.

2. Structural steel beams supporting the weight of the air conditioning system water chiller

compressors.

3. Air conditioning surface operating at below the occupied room air dew point

temperature.

4. A chilled water surface providing only radiant cooling.

5. Finned pipes or flat panels at high level in offices providing convective cooling surface.

247. Which are correct about the location of air conditioning fan coil units?

1. In a plant room.

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2. On the roof of a building.

3. Within a ceiling.

4. At high level in a room.

5. At low level in a room.

248. What does an air handling unit contain?

1. Water pump.

2. Supply and return air fans.

3. Outside air filter.

4. Heating and cooling coils.

5. Cooling tower.

249. Which of these are examples of good engineering practice in the HVAC plant room?

1. Concrete plinths and anti-vibration mountings for rotating machines.

2. Telephones and computers.

3. Hard surfaced thermal insulation.

4. Artificial lighting and emergency exit lighting.

5. Low headroom under pipes and air ducts.

250. What are correct about a fan coil unit?

1. Found in ceiling spaces over occupied rooms.

2. A small air handling unit.

3. Always installed on outdoor roof plant decks.

4. Contains a fan, air filter, heating and cooling coils.

5. Only used in office air conditioning systems.

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251. Which is the function of a VAV diffuser?

1. Manually adjustable supply air diffuser.

2. Vortex attunable valve.

3. Variable air vanes on the inlet to the supply air fan making a variable air volume flow

rate air conditioning system.

4. Self-powered thermally activated variable valve supply air room diffuser.

5. Variable active vortices created by the shape of the supply air diffuser in the ceiling.

252. Therma-Fuser is the proprietary name of a:

1. Heat sensitive air duct sealing tape.

2. Nuclear fusion reactor thermal energy power generation plant.

3. Self-powered variable flow rate supply air inlet grille.

4. Thermic lance welding system to fuse steel fabrications during construction.

5. Plastic pipe welding system.

Under floor air distribution

253. Why might an under floor air distribution system, UFAD, have benefits?

1. Keeps feet cool.

2. Quieter than ducts within ceiling.

3. Supply air within the floor void cools concrete floor slab thermal mass.

4. Keeps under floor power and communications cables cool.

5. There are no benefits as it costs more.

254. Why might an under floor air distribution system, UFAD, have benefits?

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1. It is not a new idea; the same as ancient Roman hypocaust system but now used for

cooling.

2. Fan terminal unit, FTU, within floor void provides flexible modular low velocity supply

air.

3. Noisy fan within a dusty under floor void is a health and maintenance hazard.

4. Cannot provide local heating.

5. Only used in raised floors for cabling of large computer server rooms.

255. Why might an under floor air distribution system, UFAD, with multiple fan terminal

units, FTU, have benefits?

1. Not used in commercial buildings as impractical and costly.

2. Keeping many under floor fan coil units and their air filter clean and dust-free requires

excessive maintenance work that disrupts office work.

3. Saves having a central air handling unit plant room.

4. Provides controllable microclimate at each workstation.

5. Many small fans, coils, filters and controllers are cheaper than one large air handling

unit.

Ventilation strategies

256. What does assisted natural ventilation system mean?

1. Manually openable windows, louvres and skylights.

2. May have mechanically operated ventilation devices.

3. Natural ventilation systems linked to a building management system computer.

4. Fully controlled air conditioning.

5. Always refers to natural air inlet and air outlet systems.

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257. What does mixed mode ventilation mean?

1. Ventilation fans are mixed flow type, not axial or centrifugal.

2. Building occupants actively operate some ventilation controls.

3. Fully air conditioned sealed building.

4. Mixed functional usages within a building, such as retail and hotel uses.

5. Something else.

258. Which applies to natural ventilation?

1. Only used where external climate and building design permit.

2. Always the lowest cost design option.

3. Always used in low energy buildings.

4. Airtight buildings rely on natural ventilation.

5. Natural ventilation relies on mechanically controlled permanent openable components

of the building.

259. What may a mixed mode ventilated building contain?

1. No mechanical ventilation.

2. Every room air conditioned.

3. Hollow core concrete floor slabs providing cool overnight ventilation.

4. Ground source heat pump instead of a cooling tower.

5. Cooling tower and dry air fluid cooler outdoors.

260. Where may a mixed mode ventilation system apply?

1. Mainly natural ventilation with some mechanical components.

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2. Where there is no automatic control system.

3. Unoccupied building.

4. Manufacturing building.

5. Only some areas air conditioned.

261. Low cost cooling is provided by:

1. Finding the cheapest water chiller system.

2. Maximising the use of outdoor air.

3. Using an evaporative cooling system.

4. Not having air conditioning.

5. Designing a low energy building.

262. Sketch and describe the arrangements for natural and mechanical ventilation of

buildings. State two applications for each system.

263. Describe the operating principles of four different systems of air conditioning. State a

suitable application for each.

264. State, with reasons, the appropriate combinations of natural and mechanical ventilation

for the following: residence, city office block, basement boiler room, industrial kitchen,

internal toilet accommodation, hospital operating theatre, entertainment theatre.

265. Explain, with the aid of sketches, how the external wind environment affects the

internal thermal environment of a building.

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266. List the procedure for the design of an air conditioning system for an office block.

267. Which is an appropriate statement for displacement ventilation moving air comfort

criteria?

1. Displacement supply air inlets blow air across feet.

2. Displacement supply air inlets diffuse heating air into occupied rooms just beneath the

ceiling.

3. Displacement supply air inlets diffuse air into the room to avoid causing draughts.

4. Floor supply air grilles keep feet warm.

5. Low level and floor supply air grilles are not practical.

268. Which is correct for the supply of outdoor air?

1. Must always be 1.5 air changes per hour.

2. There is no minimum recommended amount.

3. Found from room and building cooling requirement.

4. Must be 25 l/s per person at all times.

5. Around 10 l/s per person is often recommended.

269. Which is correct about mechanical ventilation?

1. Should be avoided in low energy buildings.

2. When necessary, must provide four to ten air changes per hour during heating and

cooling.

3. Should provide a minimum of four air changes per hour to ensure thorough mixing and

movement of all air within the building.

4. Only requires exhaust air fans where there is no air conditioning.

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5. Supply and exhaust air quantities must never be equal.

270. Which is correct about air pressurisation of buildings?

1. Supply and exhaust air quantities must be equal.

2. Outdoor wind environment creates internal air pressurisation.

3. When exhaust air volume exceeds supply air quantity, building is pressurised.

4. When exhaust air volume exceeds supply air quantity, building is depressurised.

5. Supply air fans do not create building air pressurisation.

271. Which is correct about the supply of outdoor air into a building?

1. Does not need to be filtered in the UK.

2. Does not need to be filtered in clean air localities.

3. Only needs to be filtered when there is a health or medical need by the occupants.

4. Air filtration is only necessary in health care, laboratory and museum buildings.

5. Incoming outdoor air is always filtered to maintain a clean and dust-free internal

environment.

272. How is the supply air flow rate determined?

1. Always determined from the number of occupants.

2. Always determined from the maximum cooling load.

3. Is 20 air changes per hour in air conditioned offices.

4. From the greatest design requirement.

5. From the maximum heating load.

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6 Ductwork design

Air flow capacity

1. 3𝑚3

𝑠 flows through a 1 m diameter duct. Calculate the air velocity.

Answer. 3.82 ms

.

2. Calculate the carrying capacities of air ducts of 400 mm, 600 mm, 1 m and 2 m diameters

when the maximum allowable air velocity is 8 ms

.

Answer. 1 m3

s, 2.26 m

3

s, 6.28 m

3

s, 25.13 m

3

s.

3. The temperature of air in a 400 mm diameter duct is 32oC d.b. on a day when the

atmospheric pressure was 101105 Pa. The static pressure of the air in the duct was 45 mm

water gauge below the atmosphere. The average air velocity was measured as 7ms

. Calculate

the air density, velocity pressure and total pressure.

Answer. 1.145 kgm3, 28 Pa, −413 Pa.

4. 2 m3

s are to flow through a 500 mm diameter duct at a static pressure of 300 Pa above the

atmospheric pressure of 101500 Pa and at a temperature of 26oC d.b. Calculate the air density,

velocity and total pressures.

Answer. 1.181 kgm3, 10.2 m

s, 361 Pa.

5. Calculate the pressures that occur when 8m3

s flows through a 20 m long, 1300 mm diameter

duct that then reduces to 1000 mm diameter and remains at 1000 mm for 20 m. The air total

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pressure at the commencement of the 1300 mm duct is 600 Pa above atmospheric. The

reducer is the 60o concentric type. Air density is 1.2 kgm3. Frictional pressure loss rates are

0.23 Pam

in the 1300 mm diameter and 0.9 Pam

in the 1000 mm diameter ducts.

Answer.

Node Pt Pa Pv Pa Ps Pa

1 600 22 578

2 595 22 574

3 591 62 529

4 573 62 511

6. Calculate the pressures that occur when 2 m3

s flows through a 12 m long, 600 mm diameter

duct that then reduces to 400 mm diameter and remains at 400 mm for 30 m. The air total

pressure at the commencement of the 600 mm duct is 250 Pa above atmospheric. The reducer

is the 30o concentric type. Air density is 1.15 kgm3. Frictional pressure loss rates are 0.85 Pa

m in

the 600 mm diameter and 6.5 Pam


Answer.


1 250 29 221

2 240 29 211

3 237 146 91

4 42 146 −104

Air pressure

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7. Calculate the density of air for a temperature of 25oC d.b. when the atmospheric pressure is

101600 Pa.

Answer. 1.183 kgm3.

8. Calculate the temperature of air that corresponds to a density of 1.1 kgm3 at standard

atmospheric pressure.

Answer. 46.6oC d.b.

9. Convert the following air pressures into pascals:

25 mm H2O, 50 mb, 125 mm H2O, 0.3 m H2O, 0.25 b.

Note that 1 b = 1 bar = 105 Pa and 1 mb = 10−3 b

Consequently, 1 mb = 100 Pa, also 1 kPa = 103 Pa

Answer. 245 Pa, 5 kPa, 1226 Pa, 2942 Pa, 25 kPa.

Duct pressures

10. An air duct branch is similar to that shown in figure 6.7. Use the data provided to

calculate all the duct pressures at the nodes. 800 mm diameter duct 1–2 is 22 m long and

carries 3 m3

s. 600 mm diameter duct 3–4 is 12 m long and carries 2 m

3

s. 450 mm diameter duct

5–6 is 10 m long and carries 1 m3

s. Branch off take is a short radius bend. Straight through

contraction has a velocity pressure loss factor of 0.05. Air density is 1.2 kgm3. Pressure drop

rates are: duct 1–2 0.43 Pam

, duct 3–4 0.85 Pam

and duct 5–6 0.95 Pam

. Total pressure at node 1 is

400 Pa.

Answer.

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1 400 21 379

2 391 21 370

3 389 30 360

4 379 30 349

5 375 23 352

6 365 23 342

11. An air duct branch is similar to that shown in figure 6.7. Use the data provided to

calculate all the duct pressures at the nodes. 700 mm diameter duct 1–2 is 20 m long and

carries 3 m3

s. 700 mm diameter duct 3–4 is 20 m long and carries 2 m

3

s. 400 mm diameter duct

5–6 is 2 m long and carries 1 m3

s. Branch off take is a right angled bend having several turning

vanes. Use circular duct data. Ignore the fact that turning vanes are not fitted to a circular

branch. The vanes are in the branch duct. Air density is 1.2 kgm3. Pressure drop rates are: duct

1–2 0.85 Pam

, duct 3–4 0.4 Pam

and duct 5–6 1.8 Pam

. Total pressure at node 1 is 200 Pa.

Answer.


1 200 36 164

2 183 36 147

3 183 16 167

4 175 16 159

5 170 38 132

6 166 38 128

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Static regain SR, (Ps3 − Ps2) = 20 Pa

12. A centrifugal fan delivers 3 m3

s into an outlet duct of 600 mm × 400 mm. The inlet

duct to the fan is 500 mm diameter. Static pressure at the fan inlet was measured as −90 mm

water gauge relative to standard atmospheric pressure. Ductwork system had a calculated

resistance of 2000 Pa. Air density is 1.16 kg m3. Calculate the pressures either side of the fan.

Answer. v1 15.3 ms

, pv1 136 Pa, v2 12.5 ms

, pv2 91 Pa, ps1 −883 Pa, pt1 −747 Pa, ps2 1162 Pa, pt2

1253 Pa, FTP 2000 Pa, FVP 91 Pa, FSP 1909 Pa.

13. The duct system shown in figure 6.16 is to be installed in a false ceiling over offices and

corridors. The air handling plant comprises the fresh air inlet, filter, chilled water cooling coil

and an axial flow fan, and are located in a plant room. Office A is supplied with 1.5 m3

s and

office B has 2.5 m3

s. Find suitable sizes for the ducts and state the performance specification

for the fan. Limiting air velocities are 2.5 ms

through the fresh air inlet grille and filter, 3 ms

through the cooling coil, 12 ms

through the fan and 5 ms

in the ducts. The fresh air inlet is

constructed from 45o louvres having a free area of 60% and wire mesh. The filter, supply

grille and cooling coil have air pressure drops of 65 Pa, 30 Pa and 40 Pa, respectively. The

contractions in the duct are at an angle of 60o and the enlargement is at 40o. Ducts are to be

sized for an air temperature of 20oC d.b.

Answer. There is more than one correct solution to this question. Ducts sizes can be:

Section 1–2, 1200 mm × 1500 mm;

Section 3–4, 600 mm × 600 mm;

Section 5–6, 1200 mm × 700 mm;

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Section 6–7, 800 mm × 400 mm;

Section 6–8, 1200 mm × 500 mm.

Section Length ∆𝑝𝑙

v pv k Fitting Duct Total

l m Pam

ms

Pa Pa Pa Pa

1–2 0 0.05 2.3 3 3 10 0 10*

2–3 3 0.07 2.3 3 0.07 105 0 105*

3–4 0 2.16 11.7 82 0.04 3 0 3*

4–5 0 0.24 5.1 15 0.36 29 0 29*

5–6 16 0.24 5.1 15 0.35 5 4 9*

6–7 0 0.42 5 15 1.25 49 0 49*

6–8 15 0.31 4.5 12 0.09 31 5 36

Index route * Total ∆𝑝 for index route 206 Pa

14. The ducts shown in figure 6.16 are an extract system removing air from two workshops

where low velocity air and heat reclaim are employed. The air flow direction arrows are to be

reversed in figure 6.16. Reverse the direction of node numbering starting with 1 at Workshop

B and 2 at Workshop A. All the duct lengths are three times those shown. The air handling

plant comprises a fan, heat reclaim cooling coil, a noise attenuator in place of the filter shown

and an exhaust grille to outdoors. Workshop A has an extract rate of 3.5 m3

s and area B has

extraction of 2.5 m3

s. Find suitable sizes for the ducts and state the performance specification

for the fan. Limiting air velocities are 2 ms

through the exhaust grille and attenuator, 3 ms

through the cooling coil, 15 ms

through the fan and 8 ms

in the ducts. The exhaust grille is

constructed from 45o louvres having a free area of 70% and wire mesh. The attenuator, extract

Comment [A1]: AQ: please check alignment of columns

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grilles and cooling coil have air pressure drops of 135 Pa, 70 Pa and 90 Pa respectively. The

contractions in the duct are at an angle of 45o and the enlargement is at 30o. Ducts are to be

sized for an air temperature of 20oC d.b.

Answer. There is more than one correct solution to this question. Ducts sizes can be:

Section 1–2, 2000 mm × 1600 mm;

Section 2–3, 1350 mm × 1600 mm;

Section 3–4, 650 mm × 650 mm;

Section 5–6, 1000 mm × 800 mm;

Section 6–7, 800 mm × 600 mm;

Section 6–8, 800 mm × 450 mm.

Section Length ∆𝑝𝑙

v pv k Fitting Duct Total

l m Pam

ms

Pa Pa Pa Pa

1–2 0 0.02 2 2 2.1 5 0 5*

2–3 9 0.06 2.9 5 0.07 225 1 226*

3–4 0 2.9 14.9 133 0.45 60 0 60 *

4–5 0 0.6 7.9 37 0.04 5 0 5*

5–6 48 0.6 7.9 37 0.35 13 29 42*

6–7 0 0.81 7.7 35 1.25 114 0 78

6–8 45 1 7.4 33 0.09 73 45 118*

Index route * Total ∆𝑝 for index route 456 Pa

Measurements

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15. State the three measurements made of air pressure within a duct, the direction they act,

what each is used for and the scientist’s name that is used to connect them. State the formulae

connecting the three pressures.

16. Explain, with the aid of sketches, how the three airway pressures are measured. List all

the equipment that would be needed. State how each item would be used.

17. A commissioning engineer needs to know the volume flow rate and mass flow rate of

air through a 600 mm diameter duct. State all the measurements that are necessary and how

they are to be acquired. Write all the formulae that would be needed and show the units of

measurement used.

18. Sketch graphs of the three airway pressures changing along a duct of length l m and

diameter d mm, showing the following cases:

(a) Total and static pressures are above atmospheric.

(b) Total pressure is above atmospheric but static pressure is below atmospheric.

(c) The duct is on the suction side to a fan and air total pressure is below atmospheric

pressure.

(d) The duct tapers from 1 m diameter to 500 mm diameter along length l m. Pressures

remain above atmospheric pressure.

(e) The duct enlarges from 300 mm diameter to 600 mm diameter while the total

pressure remains below atmospheric pressure.

(f) A 500 mm diameter duct is above atmospheric pressure. The commissioning

engineer omitted to seal a test hole halfway along the length of the duct.

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(g) Room air returns to the air handling plant through ducts that have inadequate joint

sealing along their entire length, causing significant leakage. Total pressure at the

commencement of the duct is above atmospheric. Static pressure within the duct

starts at below atmospheric pressure.

Static regain

19. Calculate the static regain and pressure changes that occur when 3 m3

s flow through a 10

m long, 450 mm diameter duct that then enlarges to 700 mm diameter and remains at 700 mm

for 20 m. The air total pressure at the commencement of the 450 mm duct is 400 Pa above

atmospheric. The enlarger is the 30o concentric type. Air density is 1.24 kgm3. Frictional

pressure loss rates are 8 Pam

in the 450 mm diameter and 0.86 Pam


Answer.


1 400 221 179

2 320 221 99

3 144 38 106

4 126 38 89


20. A 500 mm diameter duct supply air duct suddenly enlarges into a 1 m diameter plenum

chamber containing filters. Calculate the static regain and pressure changes that occur when

1.5 m3

s flows through the 35 m long, 500 mm diameter duct, enlarges, and then flows through

the 1 m diameter plenum for 5 m. The air total pressure at the commencement of the 500 mm

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duct is 200 Pa above atmospheric. Refer to figure 6.3 for the enlarger pressure loss factor. The

air density is 1.22 kgm3. The frictional pressure loss rate is 1 Pa

m in the 500 mm diameter duct and

can be assumed to be 0.05 Pam

in the 1 m diameter ducts.

Answer.


1 200 36 164

2 165 36 129

3 145 2 143

4 145 2 143


7 Controls

Actuators

1. State the types of actuators used to control heating, ventilating and air conditioning

equipment. Sketch and describe their operating principles.

2. Discuss the use of pneumatic actuators. Include in your discussion their operating

principles, the plant necessary, their interaction with electrical, electronic and digital signals,

their advantages and limitations.


3. How often does the building management system communicate data with sensors and

actuators?

1. Continuously.

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2. Once per hour.

3. Daily.

4. Every few seconds.

5. Annual reports.

4. Which of these comments are factually correct about a building management system and

are not just an opinion?

1. Physical security protection is now out of date.

2. Allows one person to control and monitor a large facility.

3. Digital recording cameras stop illegal break-ins and escapes.

4. Turn off the power source and it is useless.

5. RS232 and RS484 are types of automatic control system.

5. Commissioning of a building management system is carried out:

1. With a screwdriver.

2. At the server computer.

3. Remotely through the internet.

4. By calibrating room air temperature sensors with a thermometer.

5. With a laptop computer communicating directly with each control box.

6. What does TCP/IP stand for?

1. Television control programming, internet post.

2. Transmission control protocol, internet protocol.

3. Telephone control program, internet protocol.

4. Transmission control program, internet packages.

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5. Telephone communication package, internal protocol.

7. Which is correct about the use of carbon dioxide sensors?

1. Detect ingress of pollution from road traffic.

2. Used to vary the supply of outdoor air into rooms having VAV systems.

3. Control the intake of outdoor air into an air handling unit.

4. Warns the fire and smoke detection systems of a fire source.

5. Used to control underground car park mechanical ventilation systems.

8. Where will a computer-based building management system usually not be found?

1. Public hospital.

2. Prison.

3. Car manufacturing plant.

4. 500 person office building.

5. 100 room hotel.

9. What does the term BMS mean?

1. Building access system.

2. Building maintenance system.

3. Building management system.

4. Building monitored security.

5. Business manual security.

10. What is another common term for building management system?

1. Building control system.

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2. Building automation system.

3. Facility management computer.

4. Remote security system.

5. Building maintenance team.

11. What is an air thermostat?

1. Air temperature sensor.

2. Controller.

3. Air temperature operated switch.

4. Humidity monitor.

5. Air speed indicator.

12. Identify the vital components for user interfacing with a building management system.

1. Mobile telephone and pager.

2. Network server computer.

3. Telephone modem.

4. Computer, visual display unit, mouse and keyboard.

5. Two-way radios.


actuators?

1. When the server is switched on by a person.

2. Only when required.

3. Only when measured conditions change.

4. Regular polling.

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5. When compiling monthly reports.

14. What forms does building management system data not take when passing through the

communications cabling?

1. Alternating current of over 1.0 amp.

2. Light pulses through fibre optic cables.

3. Internet protocol data packets.

4. Electrical direct current below 0.10 amps.

5. Voltage of 10 volt maximum.

15. What types of cable system are not normally used for building management system

communications cables?

1. Copper wire.

2. Screened TV aerial cable.

3. RS 485 copper.

4. RS232 copper.

5. Fibre optic.

16. How does the building management system control engineer recognise what a control

point does?

1. Gives each one a unique number.

2. Gives each one a unique name.

3. Uses an easily identified code description.

4. Writes a digital bar code number.

5. Attaches a detailed description label.

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17. Which of these will the building management system user not see on the computer

screen?

1. Mimic drawings of the mechanical and electrical services systems.

2. Scale drawings of the building.

3. Floor plans showing sensor and camera positions.

4. Energy use reports.

5. On/off status of equipment and warning and alarm messages of faults.

18. What is a ‘point’ of a building management system?

1. No such thing.

2. Water chiller, flow control valve and temperature sensor temperature sensors.

3. Water system.

4. Air handling unit.

5. Printed circuit board in an outstation.

19. Roughly what is the average installation cost of a building management system ‘point’?

1. Only cost is sensor, around £30.

2. The labour cost of installing a wire, around £20.

3. Around £200.

4. As much as £3000.

5. The cost of a small computer, about £1000.

20. How many primary, or main, users are there likely to be of a building management

system in a public hospital?

1. One person.

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2. One hundred.

3. Three to ten.


5. All employees and contractors.

21. Who are the likely secondary, infrequent, users of a building management system, in

any building?

1. Financial accountant.

2. Building surveyor.

3. Maintenance contractor.

4. Police.

5. Any staff.

6. Energy audit engineer.

7. Building facility manager.

8. Architect.

9. Mechanical design consulting engineer.

10. Electrical design consulting engineer.

11. Cleaning contract supervisor.

12. Security staff.

22. What opens and closes a water flow control valve or an air damper in a computer-based

building management system?

1. Electric or pneumatic motor.

2. Manually operated and wheel valves.

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3. Hydraulic actuator.

4. Geared drive.

5. Winding gear.

23. Which component of a building management system controller takes input and output

direct current voltages from sensors and actuators, changing them into computer data?

1. Multiplexer.

2. The ethernet.

3. Analogue to digital converter.

4. EPROM and RAM chips.

5. Arithmetic logic unit, ALU.

24. Which of these statements about HTML is correct?

1. Another name for binary code.

2. Internationally accepted standard of control system protocol.

3. Proprietary name of open access control protocol.

4. A mathematical program language.

5. Language of TCP/IP.

25. Acquire manufacturers’ literature that demonstrates the use of computer screen system

logic diagrams for air conditioning systems. Note how the air circulation, detectors and

control systems are represented. Choose a different type of air conditioning system and create

an equivalent diagram. List all the data points to be used, with sample data.

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26. List all the points that are to be connected into the automatic control system. A point is

where a detector, switch, control panel, outstation, modem or other item, is wired into the

automatic control system. The control, commissioning and maintenance engineers need to

know this information.

27. Which of these is not a common standard for data transmission?

1. Ethernet.

2. RS484.

3. RS232.

4. RS124.

5. C-bus.

28. Which of these are ‘controllers’ in a building management system?

1. An engineer sat at a personal computer.

2. The personal computer.

3. Printed circuit boards hidden away in metal or plastic boxes in plant rooms.

4. Water and air temperature sensors.

5. Hand held devices.

29. Which of these does the building management system control system programming do?

1. Change room conditions continuously.

2. Switch boilers and chillers on and off several times a day.

3. Calculate how much to open a valve.

4. Switch plant on and off to a schedule.

5. Use mathematics to model the building.

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6. Make lots of mistakes and select the nearest correct response.

7. Correct mistakes by programmers.

8. Draw graphs.

9. Automate the actions needed.

10. Intelligently work out what to do.

30. Which of these may be found in a computer-based building management security

system?

1. Armed guards.

2. Intruder protection bars at windows.

3. Digital or video camera recording.

4. Guard dogs.

5. Record of personnel movements.

6. Identity badging and door swipe cards.

7. Fibre optic cable network communications.

8. Telephones.

9. Asset tracking e-tags.

31. Which of these comments are factually correct about a building management system

and are not just an opinion?

1. Physical security protection is now out of date.

2. Allows one person to control and monitor a large facility.

3. Digital recording cameras stop illegal break-ins and escapes.


5. RS232 and RS484 are types of automatic control system.

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32. Identify which of these is not one of the main parts of a control system:

1. Detector and controller.

2. Personal computer.

3. Heating or cooling process.

4. Actuator.

5. Internet protocol and local area network.

33. How does a heating and cooling controller work?

1. Switching heating and cooling valves fully open and closed only.

2. Calculating a control output signal to correct the zone temperature.

3. Issuing digital pulses to moves actuators.

4. Receiving signals from sensors and issuing output signals.

5. Searching the computer network for data.

34. Which of these is a temperature sensor in a building management system?


2. Thermocouple.

3. Bead of ceramic metal oxide.

4. Thermistor.

5. Bi-metallic strip.

35. What does an electronic controller contain?

1. Memory chips.

2. Video output device.

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3. Communications BUS.

4. Valve and air damper actuators.

5. Calculation unit and data store.

36. Outstation and main control boxes of a building management system are normally

found in:

1. Terminal air conditioning units.

2. Plant rooms.

3. Computer rooms.

4. Services shafts.

5. The office of the building management personnel.

37. Programming and commissioning of a building management system is carried out:

1. With a screwdriver.

2. At the server computer.

3. Remotely through the internet.

4. By calibrating room air temperature sensors with a thermometer.

5. With a laptop computer communicating directly with each control box.

38. Automatic heating and cooling system control is needed because:

1. Sunshine produces a constant cooling load on the building.

2. Outdoor weather conditions vary randomly.

3. Each day’s outdoor air temperature is predictable.

4. Occupants of the building set their own temperature requirements.

5. Individual office air conditioning can be switched off when unoccupied.

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39. Where will a computer-based building management system be found in Australia?

1. 20 bed private hospital.

2. Motel.

3. Car manufacturing plant.

4. 50 person office building.

5. 100 room hotel.

40. What is an air thermostat?

1. Air temperature sensor.

2. BMS controller.

3. A switch.

4. Air condition monitor.

4. Air temperature room indicator.


actuators?

1. When required by the engineer.

2. Several times per hour.

3. A few times daily.

4. Multiple times a minute.

5. When required to generate activity reports.

42. What forms does building management system data take when passing through the

communications cabling?

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1. Alternating current of over 1.0 amp.

2. Continuous digital data.

3. Internet protocol data packets.

4. Single phase current below 0.10 amp.

5. Three phase direct current.

43. What types of cable system are used for building management system communications

cables?

1. 240 volt alternating current.

2. Screened TV aerial cable.

3. RS 485 and RS232 copper 10 volt twisted pair.

4. Mineral insulated copper conduit.

5. Any earthed cable.



1. One person.

2. One hundred.

3. Three to ten.



45. Which of these are ‘controllers’ in a building management system?

1. An engineer sat at a personal computer.

2. The personal computer.

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3. Printed circuit boards hidden away in metal or plastic boxes in plant rooms.

4. Water and air temperature sensors.

5. Hand held devices.

46. Which of these does the building management system control system ‘programming’

do?

1. Measure room conditions occasionally.

2. Switch boilers and chillers on and off several times a day.

3. Calculate how much to open and close motorised valves and dampers.

4. Select the nearest correct response to condition changes.

5. Intelligently work out what to do.

47. Which of these comments are factually correct about a building management system

and are not just an opinion?

1. Only prisons need physical security protection.

2. A few people control and monitor a large facility.

3. Cameras stop illegal break-ins and escapes.


5. C-bus and internet are types of automatic control system.

48. How has building energy management system, BEMS, become popular?

1. Good salesmanship by global corporations.

2. Increased demand from building users for monitoring, recording and automation of

actions that would have taken hours of skilled manual labour.

3. Shortage of skilled maintenance staff.

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4. Fashion among building owners.

5. Reduces staff.

49. What is the difference between building energy management systems, BEMS and

building management systems, BMS?

1. Often nothing.

2. BMS includes additional functions such as camera security monitoring and access

control systems.

3. BMS costs more than BEMS.

4. BEMS costs more than BMS.

5. Only BMS uses the internet.

50. Which reports does the building owner want from the BMS?

1. Schedules of zone temperatures on a daily basis.

2. Lift usage data.

3. Detailed energy consumption correlated to weather and dates.

4. Only wants to see reports that state there are no faults with the building.

5. Building owner is too remote from day to day use of such an investment and does not

see any reports.

51. Which reports does the building user or manager want from the BMS?

1. Preferably none, cannot be bothered with such technical information.

2. Fault reports, zone temperatures, energy consumption, lift data, security camera views,

access logs for confidential areas, all on a daily basis.

3. All BMS output is dealt with by building maintenance team and not the manager.

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4. General users of the building do not have access to the BMS.

5. Reports are always monitored by the BMS supply contractor and not the on-site staff.

52. Which reports does the energy auditor want from the BMS?

1. Daily schedules of zone temperatures.

2. Lift and security camera usage data

3. Zone temperatures, mechanical and electrical systems schematic drawings, detailed

energy consumption, weather data, gas and electrical hourly peak demands each month

and trend graphs.

4. All fault reports.

5. Energy auditor is too remote from day to day use of the building and does not see any

reports.

53. Which reports does the control system maintenance technician want from the BMS?

1. Schedules of zone temperatures on a continuous basis.

2. Lift usage data.

3. Detailed energy consumption correlated to weather and dates.

4. Only wants to see reports that state there are no faults with the building.

5. Those reports which reveal where repair work is immediately needed.

54. What does a BMS look like?

1. Front end PC system, robust metal boxes in plant rooms with circuit boards and many

10 volt wires to sensors and final control elements such as valve motors.

2. Multiple PCs around a large site with user access at each.

3. Only a metal cabinet containing logic controllers and wires.

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4. Laptop computer and wireless communications to all elements of the system.

5. Never seen, no idea.

55. What does DDC stand for?

1. Dangerous direct current.

2. Dedicated digital control.

3. Distributed digital controllers.

4. Dedicated direct computers.

5. Direct digital control.

56. Which of these types of automatic control systems is invalid?

1. Room air thermostat switching pumps, valves and dampers on and off.

2. Room air thermostat modulating an electrically operated damper and valve.

3. Digital communications with electrical or pneumatic signals and actuator power

supply.

4. 415 volt control circuits, single and three phase controllers.

5. Manual control switches and valves.

6. Entirely pneumatic sensing devices and actuator power supply.

57. What is an outstation?

1. Human railway interface.

2. A discharging device.

3. Remote computer for personal use in a BEMS.

4. Control actuator.

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5. Metal box control panel in a plant room with printed circuit boards, programmable logic

chips, RAM, EPROMS and 10 volt wires to sensors and control elements in the field.

58. How is a BMS observed by people?

1. Physically looking at control valves and dampers to see what they are doing.

2. Reading a PC screen.

3. Downloading data from an outstation to a laptop through an RS485 cable.

4. Through the internet.

5. It is not.

59. What is the input and output signal to a valve or damper actuator in a DDC system?



3. 10 volt direct current.

4. Zero to one bar pneumatic air pressure.

5. Zero and one digital data bits.

60. What is the difference between a BMS front end PC and a field control panel?

1. One has a screen and keyboard.

2. PC provides a window into the data system contained in the field controller panels.

3. Field panels are just wire junctions and have no software in them.

4. Field control panels have all the control and communication software while the PC only

displays system graphics, spreadsheet data and online charts of data as it is measured.

5. They equally share control and communication functions.

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61. How is BMS programming carried out?

1. All control software is written onto the hard disk drive of the front end server PC and

accessed through the network by each controller.

2. System graphics and control software packages for each type of control function are cut

and pasted from a library into files on a laptop computer later downloaded to each

relevant field control panel through an RS485 data cable from the laptop.

3. Geeks at PC workstations spend 60 hours a week writing software that is sent through

the internet to the field control panels anywhere in the world.

4. I have no idea.

5. Software is generated by intelligent programming fuzzy logic neural network server

computers in Minneapolis.

62. What is the name of the generic data communication system used in BMS?

1. Open system.

2. BACNet.

3. LONtalk.

4. Ethernet.

5. GSM telephone.

63. Which communication protocol (language) passes through BMS data systems?

1. Binary 32 data bit streams.

2. TCP/IP.

3. HTTP.

4. Wi-Fi.

5. Token ring.

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64. What does TCP/IP stand for?

1. Television control programming, internet post.

2. Transmission control protocol, internet protocol.

3. Telephone control program, internet protocol.

4. Transmission control program, internet packages.

5. Telephone communication package, internal protocol.

65. Which of these acronyms is not related to data communications within building

management computer-based systems?

1. BACNet.

2. LONtalk.

3. MODbus.

4. GSMnet.

5. ARCNet.

66. Which of these is not used to communicate with a BMS?

1. Pager.

2. Mobile digital phone.

3. Two-way radio.

4. Handheld PDA.

5. Laptop computer.

67. Which of these is not the reason why BMS is implemented widely?

1. Complexity of building services systems.

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2. Extensive control system programming requirement.

3. Increasing demand for system monitoring and reporting.

4. Energy-saving technology and verification requirements.

5. High cost of computer equipment and PCBs.

68. How is a computer-based building energy management system commissioned when

physical installation is complete?

1. Technician edits data on screen with a laptop or front end PC server computer.

2. Each room air temperature sensor is calibrated with a screwdriver and mercury in glass

thermometer.

3. Each valve and air damper actuator is calibrated with an air flow anemometer.

4. Each on/off function is visually confirmed in the field while a programming technician

at the front end PC server commands the actuator to move and communicate with two-

way radio.

5. All zone and duct air temperatures, CO2 levels, pressures and air flow rates are

measured and compared with BMS displayed values to calibrate the software and

sensors.

69. What is another common term for building management system?

1. Building control system.

2. Building automation system.

3. Facility management computer.

4. Remote security system.

5. Building maintenance team.

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70. A heating and cooling controller works by:

1. Switching heating and cooling valves fully open and closed.

2. Calculating a control output signal to correct the zone temperature.

3. Issuing digital pulses to move actuators.

4. Receiving signals from sensors.

5. Searching the computer network for data.

71. A temperature sensor in a building management system is usually a:


2. Thermocouple.

3. Bead of ceramic metal oxide.

4. Variable voltage source.

5. Bi-metallic strip.

72. Outstation and main control boxes of a building management system are normally

found in:

1. Terminal air conditioning units.

2. Plant rooms.

3. Computer rooms.

4. Services shafts.

5. The office of the building management personnel.



1. One person.

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2. One hundred.

3. Three to ten.



74. What does a building energy management system, BEMS or BMS, do?

1. Put a fancy front to a simple control and security system.

2. Nothing more than people can do.

3. A lot more than people can do.

4. Allow one person to monitor, control and produce written reports on a building of any

size without leaving a desk.

5. Waste a lot of capital cost and create an ongoing maintenance cost commitment to one

supplier.

Components

75. List the components of an automatic control system for:

(a) domestic gas fired central heating;

(b) ducted air heating and ventilation system in a single-storey factory used for assembly of

electronic components;

(c) single duct variable air temperature air conditioning system for a lecture theatre for 120

people;

(d) single duct fan coil air conditioning system serving a 12-storey office building. Chilled

water refrigeration compressors and oil fired boilers are used.

76. Explain what is meant by analogue and digital values in control.

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77. Explain how an analogue signal can be created and used to represent room air

temperature.

78. Draw a graph of the output signal from a thermistor temperature sensor that has an

operating range of 0oC to 40oC and a constant current of 5 milliampere. A linear voltage

output of 0–10 volt is produced by the thermistor. 10 volt corresponds to 40oC air

temperature. Calculate the voltage that corresponds to an air temperature of 25oC and the

resistance of the thermistor at this value.

79. Explain the sensing and operating principle of:

(a) thermistor temperature detector;

(b) humidity detector;

(c) enthalpy detector;

(d) air pressure transmitter;

(e) a detector to measure the air volume flow rate in a duct and use its value for automatic

monitoring and control;

(f) weather compensator;

(g) water temperature detector.

80. An open plan occupied space is served by a single duct variable temperature air

conditioning system. Explain how the average air temperature and humidity of the space can

be sensed and used for the control of the hot and chilled water diverting control valves. Sketch

the arrangement of the detectors, controllers and actuators on a plant schematic.

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81. A thermistor produces a 5 volt direct current output when passing a control current of

10 milliampere. Four thermistors are used to find the average of four air temperatures in a

lecture theatre. Draw a suitable wiring circuit that would produce an average voltage for use

by the controller. Calculate the resistance of the circuit. Validate your connection design by

calculating the circuit resistance from first principles.

82. Explain the use of enthalpy control of the fresh air intake to a ducted ventilation or air

conditioning system. State why it is used and what limitations may arise.

83. Explain, with the aid of sketches, what an electric solenoid, relay and contactor is. State

what the device is used for.

84. Explain how a personal computer is used to monitor and control an air conditioning

system. State how 24 volt, 240 volt and 415 volt alternating current electric powered actuators

and plant are interfaced with the binary code used by the computer and network cables. Give

examples of the software used by the supervising computer and the engineering management

personnel in dealing with the data accessed.

85. What does the mechanical services switchboard, MSSB, do?

1. Router for all telephone calls between property services staff.

2. Automatically controls all air conditioning and transportation systems on the campus.

3. It is the manually operated switchboard for all mechanical services systems within the

building.

4. Switches all the electrical sub-circuits for the whole building.

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5. Only needed in buildings that do not have a computer-based building management

system.

86. Automatic heating and cooling system control is needed because:

1. Sunshine produces a constant cooling load on the building.

2. Outdoor weather conditions vary randomly.

3. Each day’s outdoor air temperature is predictable.

4. Occupants of the building set their own temperature requirements.

5. Individual office air conditioning can be switched off when unoccupied.

Control mode

87. Discuss, with examples, how lags occur in the detection and control of air conditioning

within an occupied building.

88. Explain the following terms: proportional, integral, derivative, proportional plus

integral, proportional plus integral plus derivative, offset, differential, boost, controlled

variable, controller, dead time, set point.

89. State the ten controller operation methods used. Briefly describe the principle of each

method.

90. Identify which of the following modes of automatic control are usually employed in

occupied buildings for their mechanical services:

1. Direct acting.

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2. Integral action.

3. Derivative action.

4. Proportional plus integral action.

5. Fast response.

91. Identify which of the following modes of automatic control are usually employed in

occupied buildings for their mechanical services:

1. Direct acting.

2. Propensity action.

3. Derivative action.

4. Proportional plus integral action.

5. Fast response.

Control schematics

92. A public entertainment theatre and conference centre seats 500 people. The basic layout

of the air conditioning system is shown in figure 7.7. Add a chilled water cooling coil and

three-port diverting valve on the chilled water circulation. The room condition is to be

maintained at 20oC d.b. ±2oC and 50% percentage saturation ±10%. The outdoor air

temperature varies from −10oC d.b. to 32oC d.b. during the year. Design an automatic control

system that will maintain thermal comfort throughout the year. Specify the types of detection

and control equipment necessary. Draw a schematic diagram of the air handling plant and

control system to describe its components, locations and modes of control. Draw operating

graphs for the controls to demonstrate the voltage signals that correspond to plant status.

Describe the logical operation of the control sequence. Chilled water is available at a flow

temperature of 6oC and hot water is at 82oC. Ignore the boiler and refrigeration plant

operations. Frost protection of the building and air handling plant is needed due to the low

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external air temperature. Make any assumptions that may be considered necessary. The design

may be discussed with colleagues, the tutor and suppliers of control systems.

93. Explain the logical operation of the control of a variable air volume air conditioning

system. Draw the plant and control equipment schematic diagram.

Fan control

94. Discuss the four methods used to control the output performance of centrifugal and

axial flow fans. Illustrate the methods to show their application. Sketch the effect of each

method on a fan performance graph. Each graph is to identify the duct system resistance, the

control effect and the combined performance point. State the energy savings, advantages and

limitations of each method.

Refrigeration system control

95. Explain the methods used to control the chilled water output performance of

refrigeration plant. Include the various types of refrigeration system and compressors.

96. Two three-cylinder refrigeration reciprocating compressor and water chilling evaporator

sets are to produce a flow temperature of 5oC when the return water is at 11oC. The minimum

chilled water temperature is 3oC. The tolerance of the chilled water temperature control is

±0.5oC. Each cylinder corresponds to a cooling load dead band of 1oC around the set point.

Design a control schematic for the refrigeration plant. Draw a capacity control graph to show

the control steps and the mean chilled water flow temperature that will be produced.

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97. Water chillers are a major source of cooling for air conditioning. List the types of

packaged water chillers available; provide sketches to show their principle of operation and

typical application.

Answer. Vapour compression reciprocating, scroll, screw and centrifugal. Absorption, gas

fired, waste heat supplied.

98. Multiple chillers are used in large buildings to match capacity with demand. Sketch and

describe the following means of providing a satisfactory cooling service while minimising

energy use. Parallel and series connected chilled water evaporators. Parallel and series

connected condenser water cooling heat exchangers. Chilled water primary circuit. Chilled

water secondary circuits. Chilled water common header. Constant pump speed primary chilled

water circuit. Variable speed secondary chilled water circuits. The use of chilled water

pressure difference sensors and control valves.

99. Heat rejection is where indoor cooling is transferred to the external environment.

Explain with the aid of sketches and manufacturers’ literature how the following systems

function and where they can be employed: direct air cooled condensers; water cooled and

evaporative condensers; open circuit cooling tower; closed circuit cooling towers; forced

draught cooling tower; induced draught cooling tower; cross draught cooling tower;

evaporatively precooled dry heat exchanger.

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100. Controlling water chilling plant is a big part of economising on energy use. Explain

with the aid of sketches and resource material, the meaning of the following control methods:

each chiller in a multi-chiller installation is a capacity step; multi-compressor step control;

compressor cylinder unloading; variable speed control; hot gas bypass; evaporator pressure

regulator.

101. Explain how centrifugal, screw, gar and scroll refrigeration compressors are controlled

to match refrigeration demand.

102. Find a BMS company’s single chiller control graphic and explain the control functions.

Show typical temperature set points.

103. Four centrifugal water chillers are connected in parallel to a common chilled water flow

and return header. Sketch the CHW pipe and chiller schematic. Show one typical pumped

secondary CHW circuit connected to the common header. The secondary circuit supplies

AHU coils through diverting control valves. Annotate the schematic to demonstrate how the

control system functions to minimise energy and show typical temperature set points.

104. A roof mounted cooling tower is to have a condenser water diverting valve to control

heat rejection capacity from a reciprocating water chiller located in the basement. Sketch and

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describe the control schematic to demonstrate functionality and show typical temperature set

points.

105. Find a BMS manufacturer’s digital controller configuration schematic for multiple

water chillers and cooling towers. Explain the functionality of the system and show typical

temperature set points.

106. Sketch and describe a typical digital control schematic for multiple cooling towers and

show typical temperature set points.

107. Show a BMS manufacturer’s control graphic for multiple water chillers, show typical

temperature set points and explain its operation.

108. Decide on a climate region for your answer. Give reasons for sequencing unequally

sized water chillers in a large commercial building. For example, when each chiller capacity

is 15%, 25%, 60% of the design’s cooling load. Quote a specific installation if one is known

to you.

Wiring diagram

109. Draw an electric wiring diagram, similar to figure 7.16, for the heating and ventilating

system in a shop. The supply and extract fan motors are single phase. The fresh air inlet fan

has an electric resistance heater that raises the supply air to 20oC. A low temperature limit

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thermostat in the supply duct switches the supply fan off after a 2 minute time delay. The

extract fan is started from a 30 second time delay unit after the supply fan has started. A time

controlled switch activates the fans and two fan powered single phase electric resistance

heaters in the shop. An air thermostat for each heater switches them on and off. Each fan and

heater has an ‘on’ status indicator lamp. A frost thermostat is set at 8oC in the shop and it

overrides the time switch. Three smoke detectors switch on a smoke extract fan. The smoke

extract system is always operational and it has a ready status indicator lamp, a smoke alarm

indicator lamp and an audible smoke alarm.

110. Draw the wiring diagram for a three phase 415 volt power supply to two air

conditioning fans, a refrigeration compressor and a steam humidifier. Each item has a triple

pole and neutral isolating switch. The humidifier is controlled from a 10 volt control signal

from a humidity detector within the air duct. The supply duct air temperature controls a hot

water valve. There is an isolating switch for all the air conditioning circuits. An overload

circuit breaker protects the whole system. The plant room has a three phase distribution board.

Single phase is used by the temperature and humidity controller.

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8 Commissioning and maintenance

Commissioning work

1. Write a complete schedule for the commissioning work necessary on the air handling

equipment only for a single duct air conditioning system serving a lecture theatre. Heat is

provided from a low pressure hot water two -pipe system from a boiler house. Cooling is

provided by chilled water two-pipe systems.

2. Explain the difference between scheduled and unscheduled maintenance work on an air

conditioning system. State the items that will require replacement, their likely length of

normal service and whether they should be held in storage on the site.

3. List the order in which each part of an air conditioning system will be commissioned. State

the condition required of the building works for each stage of commissioning.

4. Explain the following:

(a) frequent starting of fans and pumps is to be avoided;

(b) internal surfaces of air ducts, cooling towers, water storage tanks and water

circulation pipework systems need to be cleaned and disinfected;

(c) how cleaning and disinfection work is conducted;

(d) methods available for the starting of the electrical motor drive on a fan;

(e) why the first installed air filters will be temporary;

(f) proportional balancing;

(g) need for vibration measurements;

(h) harmonic interference from electrical equipment;

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(i) fan speed regulation;

(j) full load start;

(k) why and where gas detectors are used;

(l) tolerance limits;

(m) how cross-contamination between services is avoided;

(n) where water aerosols originate;

(o) what reduces the effectiveness of chlorine dosing and disinfection.

5. List the instruments that may be needed to commission an air conditioning system.

Describe, with the aid of sketches, the operating principle and method of use of each

instrument.

Duct leakage

6. A leakage test on completed ductwork revealed the following data; duct static pressure 45

mm H2O, duct surface area 120 m2, duct air temperature 12oC, orifice plate flow coefficient

0.67, orifice throat diameter 70 mm, orifice pressure drop 160 mm H2O. Calculate whether

the duct system meets the maximum leakage criteria when it is calculated from

0.027𝑝s0.65 lm2s

duct surface area.

7. A commissioning engineer is to carry out a leakage test on a section of completed

ductwork. On the day of test, the duct surface area is measured as 93 m2, duct air temperature

14oC, orifice plate flow coefficient 0.68, orifice throat diameter 50 mm and orifice pressure

drop 230 mm H2O. Calculate the duct static pressure h mm H2O that must be maintained by

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the test fan in order for the duct system to meet the maximum leakage criteria when it is

calculated from 𝑄 = 0.027𝑝s0.65 lm2s

duct surface area.

8. A leakage test on a section of completed ductwork with a surface area of 260 m2, duct air

temperature 18oC, venturi flow coefficient 0.97, throat diameter 60 mm and venturi pressure

drop is 190 mm H2O. The duct static pressure is held at 62 mm H2O by the test fan. Calculate

whether the duct system meets the maximum leakage criteria when it is calculated from

𝑄 = 0.009𝑝s0.65 lm2s

duct surface area.

Maintenance manual

9. Design the layout for a maintenance manual for one of the air conditioned buildings

mentioned in this book, or a case study of your choice. The completed instructions will be

implemented by a contract company as the result of competitive tendering for the work. The

document is to state the plant that is to be maintained, how it is to be started, stopped, shut

down in an emergency and the timing for maintenance operations. State precisely what work

is to be undertaken at the appropriate time intervals. The maintenance instructions must be

easily understandable by the client’s representative, who is not necessarily a building services

engineer.

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Maintenance work 10. Describe how failure of plant during normal use is overcome to maintain the air

conditioning service.

11. Discuss the approach to a suitable maintenance programme for the air conditioning in

the following applications:

(a) large general hospital

(b) university

(c) residential buildings in the UK

(d) office accommodation in Brisbane

(e) manufacturing building including the containment of biological and radioactive

materials.

(f) comfort control for the workplace in the UK

12. A refrigeration condenser is cooled with water that is circulated to an evaporative

cooling tower on the roof of a hospital in a city. State the actions that are taken to ensure that

the tower operation will not cause health hazards to the patients and the public.

13. Design a maintenance log for a city office building that has low pressure hot water

heating and a single duct heating and ventilation system. There is no refrigeration plant.

Maintenance work is to be carried out by contractors. The office users will allow some

interruption of the heating and ventilating systems during 09.00–17.00 hours for repairs.

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14. Discuss the reasons for using standby plant in an air conditioned building. Include the

implications for plant room size, storage commitment, stock control, capital and recurring

costs for the user.

15. List the frequency of visual checks, physical measurement, changeover of running plant

and planned replacement of the items and systems in an air conditioned building of your

choice from the types given in question 11

16. Find the maintenance records for the building that is accessible to you. This may be a

residence, office, factory, warehouse, college or university. Request the help and cooperation

of the professionally employed maintenance engineering staff where this is applicable. Write

a report on the comprehensiveness of the records that are kept. Make appropriate

recommendations as to improvements that should be made.

17. Compare the quality of maintenance work and its recording when it is conducted by

employees of the same organisation that uses the site, and contract companies. This may

involve the acquisition of information from several sources that are dissimilar. Discuss the

advantages and the budgetary control implications of each method.

18. Draw a schematic diagram of part of an air conditioning system. Show the location of

all the necessary valves, dampers and controls. Number all the controls and test points and

produce a schedule of their data. Write on the diagram all the data that will be needed by the

commissioning and maintenance engineers.

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19. Design a maintenance log for the refrigeration plant of an air conditioning system that

serves a 10000 m2 floor area complex of offices and computer manufacturing facilities.

Evaporative cooling towers are located on the roof. Refrigeration plant is in a ground floor

plant room. Each room has a chilled water cooling coil and local temperature control. Make

any assumptions about the systems that are necessary. State the intervals between servicing

and replacement work.

20. Explain the advantages gained when the original designer of an air conditioning system

publishes the schedules for commissioning and maintenance work. State the information that

is included and the form that the documentation should take. State how a computer-based

system can aid good maintenance practice.

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9 Fans

Commissioning fans

1. Design the layout for a commissioning task sheet for the fan and duct systems within an air

conditioned building. The completed instructions will be implemented by a contract company

as the result of competitive tendering for the work. The document is to state the plant that is to

be commissioned and precisely what work is to be conducted.

Fan and system operation

2. An axial flow fan delivers air at the rate of 12 m3

s when the ductwork system resistance is

120 Pa. The 415 volt three phase driving motor has a power factor of 0.7. The overall

efficiency of the belt drive is 96%. The fan impeller has an efficiency of 60% at the design

flow. The fan power at zero air flow, when it is only generating static pressure within its

casing, is 20% of the design flow value. Calculate the motor power for the design and closed

damper conditions.

Answer. At the design air flow, power 4.286 kVA; at the closed damper air flow, power 0.857

kVA, phase current 1.19 ampere.

3. An axial flow fan runs at 940 RPM and has a blade angle of 28o. It passes air at a density

of 1.21 kgm3 into a duct system that has a resistance of 100 Pa when the air flow is 5 m

3

s. The

outlet air velocity from the fan is 11 ls. The 415 volt three phase drive motor has a power

factor of 0.92. The motor and drive has an overall efficiency of 65% and the impeller has an

efficiency of 80%. The minimum power consumption at zero air flow would be 0.25 kVA.

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The fan performance data are shown in table 9.8. Calculate and plot the fan characteristic

curves for fan velocity and static pressures, the duct system resistance and the motor input

power. Use file axial. Find the fan and system operating conditions and the current that will

be taken by the motor.

Table 9.8 Fan data for question 3.

Q m3

s FTP Pa

0 160

1 155

2 150

3 140

4 125

5 90

6 50

7 0

Answer. Q 4.9 m3

s, FTP 90 Pa, 1.2 kVA, 1.7 amp.

4. A mixed flow exhaust fan runs at 1450 RPM and handles air at a density of 1.2 kgm3. The fan

outlet diameter is 500 mm. The duct system has a resistance of 600 Pa when the air flow is

1100 ls. The outlet air velocity from the fan is 7.6 m

s. The 415 volt three phase drive motor has

a power factor of 0.7, the motor and drive has an overall efficiency of 70% and the impeller

has an efficiency of 82%. The minimum power consumption at zero air flow would be 0.4

kVA. The fan performance data are shown in table 9.9. Calculate and plot the fan

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characteristic curves for fan velocity and static pressures, the duct system resistance and the

motor input power. Use file axial. Find the fan and system operating conditions and the

current that will be taken by the motor.


Q ls FTP Pa

0 750

250 800

500 850

750 850

1000 780

1250 630

1500 450

1750 200

Answer. Q 1200 ls, FTP 680 Pa, 2.3 kVA, 3.2 amp.

5. A belt driven centrifugal air conditioning supply fan runs at 700 RPM and handles air at a

density of 1.18 kgm3. The fan outlet diameter is 750 mm. The duct system has a resistance of

500 Pa when the air flow is 4000 litre/s. The outlet air velocity from the fan is 7.6 ms

. The 415

volt three phase drive motor has a power factor of 0.92. The motor and drive has an overall

efficiency of 75% and the impeller has an efficiency of 71%. The minimum power

consumption at zero air flow would be 1.0 kVA. The fan performance data are shown in table

9.10. Calculate and plot the fan characteristic curves for fan velocity and static pressures, the

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duct system resistance and the motor input power. Use file axial. Find the fan and system

operating conditions and the current that will be taken by the motor.


Q ls FTP Pa

0 750

500 775

1000 780

1550 775

2000 765

2500 750

3000 700

3500 650

4000 576

4500 500

5000 360

5500 80

Answer. Q 4200 ls, FTP 550 Pa, 5.6 kVA, 7.8 amp.

6. An air conditioning system has a design air flow of 3 m3

s. The supply air duct system

frictional resistance is 450 Pa. The supply air filter has a pressure drop of 40 Pa when clean

and 180 Pa when it is ready to be changed. Use the average filter pressure drop for the

analysis. The air conditioning system is operated for 200 hours per month. The fan handles air

at an average density of 1.2 kgm3 through the year. The fan impeller efficiency is 80%, motor

efficiency is 66% and the motor power factor is 0.92. Assume that the overall efficiency

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remains constant at any air flow. The motor power used at zero supply air flow is 0.8 kW. The

fan discharge duct is 700 mm × 600 mm. Table 9.11 shows the supply air fan performance

data. The building is in southern England where the load profile on the air conditioning

system is indicated in Table 9.12. The supply air requirement for each month is the average

for the month to match the thermal loads. A higher temperature differential between the

supply and room air is maintained in winter and this reduces the supply air quantity. Free

cooling is used in the mild weather. Electricity costs 9 p/kVAh. The fan is operated at the

constant speed of 960 RPM.

Table 9.11 Supply air fan performance data for question 6

Air flow Q ls FTP Pa

0 800

500 810

1000 820

1500 820

2000 800

2500 750

3000 650

3500 500

4000 300

4500 50

Table 9.12 Monthly supply air flow required for question 6

Month Heating/cooling load % Supply air required Q m3

s

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January 35 1.05

February 42 1.26

March 56 1.68

April 76 2.28

May 97 2.91

June 100 3.0

July 97 2.91

August 90 2.7

September 77 2.31

October 57 1.71

November 40 1.2

December 31 0.93

Manual calculations and file vfc can be used to compare annual costs for the following:

(a) no fan performance control;

(b) supply duct air volume control damper;

(c) two speed fan motor producing 960 and 550 RPM;

(d) variable frequency fan speed control.

Answer. Annual energy costs (a) £979.87, (b) £822.35, (c) £620.30, (d) £426.53. Annual cost

savings (a) £157.52, (b) £359.57, (c) £553.34.

Fan control

7. Discuss the equipment that is needed to start, control and monitor the safe operation of the

speed of electric drive motors on air conditioning system fans. State the economic and

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technical factors that are included in the decision as to which method is applied to an

application.

8. Explain the characteristics of the different methods of controlling the flow of air through a

ductwork system in relation to the energy cost of using the whole installation.

9. List the advantages that are gained by operating an air conditioning fan at the lowest

possible rotational speed while meeting the required duty.

Fan curves

10. Explain what happens to the fan total pressure rise when the fan static pressure drops to

zero.

11. Why can the duct system characteristic curve be calculated and drawn without reference

to the duct system resistance data?

12. State the fan laws and show how they are used to generate predictions of fan

performance.

13. State the data that are obtained from standard tests on fans.

14. Explain why and when fans would be connected in series with each other. Sketch the

combined characteristics of two fans that are closely connected in series. Sketch the duct

system resistance curve and identify the overall fan and system operational point.

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15. Discuss how the equipment manufacturer and the building services designer obtain the

maximum energy efficiency from a fan and drive system.

16. Explain why the fan motor power consumption does not diminish to zero when the duct

system dampers are all closed.

Fan testing

17. The Daylesford Impeller Company manufactures a range of centrifugal fans for air

conditioning systems. A prototype fan was tested at an air flow rate of passed 1800 ls with an

impeller of 420 mm diameter producing a fan static pressure of 150 Pa when the impeller was

running at 1200 RPM. The measured electrical input power to the motor of the fan tested was

800 W. Predict the performance of a 700 mm diameter fan impeller that will be run at 16 hertz

and is to be geometrically similar to the prototype.

Answer. N1 20 Hz, N2 16 Hz, Q2 6667 ls, ∆𝑝2 267 Pa, P2 5267.5 W.

Fan types

18. Sketch the characteristic curves for a backward curved centrifugal fan and ductwork

system to show the relationship between fan total, static and velocity pressures, motor power

and the ductwork system resistance. Do not look at any published graphics while undertaking

this question.

19. List the ‘overhead’ power requirements of a fan and electric motor drive plant. State

how these minimum power requirements affect the shape of the fan power characteristic

curve.

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20. State the designer’s objectives when selecting the operating point on a fan characteristic

graph.

21. Explain how fan manufacturers test fans and how they generate performance data for a

range of fan sizes and rotational speeds.

22. State the electric motor speeds that are used and how these speeds are achieved.

23. Explain, with the aid of practical examples, how the rotational speed of a fan impeller is

maintained at a different speed to that of the driving motor.

Fans and systems

24. State the functions of fans within building services.

24. Explain how fans create movement in air.

25. State the limiting factors that are included in the design of fan and duct systems.

26. List the components of fan and drive systems. Comment upon how they are

manufactured and their relative cost to the user.

27. List the types of fan and their principal applications.

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28. Discuss the advantages and disadvantages of installing a large duty centrifugal fan

within a builders’ work plenum when compared with a metal plenum.

29. List the safety features that are to be considered when designing a fan installation.

30. Explain how the maintenance access to fans and their associated items of plant, such as

air filters, drive system and heat exchange devices, is provided during the design of the

overall system and building. State the importance of such access, the likely frequency of

maintenance work and the safety precautions that are to be taken.

31. Discuss the problems that are associated with manual entry into a positively or

negatively pressurised plenum or ventilated space.

32. State the problems that are associated with running a fan against closed duct dampers.

33. What problems may be created within the ventilated rooms when starting a centrifugal

supply or extract fan, or a combination of both?

Opening force

34. A forward curved centrifugal fan maintains a static air pressure of 75 Pa above that of

the atmosphere, within the fan acoustic plenum. An access door of 750 mm width and 2200

mm height allows entry for regular maintenance. The door is hinged along one vertical side

and has a handle in the opposite side. Calculate the manual force that is necessary to open the

door.

Answer. F2 6.3 kg.

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35. The supply air outlet duct from a packaged roof mounted air conditioning unit is 500

mm wide and 700 mm high. The supply air flow to the duct system is to be 2700 ls of air at

33oC d.b. during winter use. Calculate the velocity pressure of the supply air as it leaves the

packaged unit.

Answer. FVP 34 Pa.

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10 Fluid flow

Air ducts

1. A 300 mm internal diameter galvanised sheet steel duct is to carry air at 20oC d.b. with a

pressure loss rate of 2 Pam

. Calculate the air flow rate that can be carried.

Answer. 0.507 m3

s.

2. Calculate the air velocity in a 450 mm internal diameter galvanised sheet steel duct when

the air temperature is 20oC d.b. and the pressure loss rate is 0.6 Pam

.

Answer. Q 0.782 m3

s, v 4.92 m

s.

3. An air conditioning system is to have galvanised sheet metal ducts carrying air at 20oC d.b.

at a maximum velocity of 7.5 ms

. The maximum allowable frictional resistance of straight duct

is to be 3 Pam

. The air flow rates to be carried in different sections of duct are 0.12, 0.3, 0.6, 1

and 2 m3

s. Ducts are manufactured in sizes from 100 mm internal diameter upwards in 50 mm

increments. Calculate the most economical size for each duct.

Answer.

Q m3

s d mm

0.12 200

0.3 250

0.6 350

1 450

2 600

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Flow calculation

4. State the engineering and economic objectives of heat distribution systems. Give examples

of good practice. Outline the economic considerations needed.

5. Calculate the maximum carrying capacity of a 28 mm copper pipe at a pressure loss rate of

1200 Pam

when the water temperature is 75oC.

Answer. 1.014 kgs

.

6. Find the copper pipe size appropriate to a cold water flow rate of 0.123 kgs

and a pressure

loss rate of 850 Pam

.

Answer. 15 mm.

7. A low temperature hot water heating system that serves air conditioning heater coils, has a

two-pipe circuit that is to be sized on the basis of a constant pressure loss rate of 500 Pam

.

Calculate the maximum flow capacity of copper pipes from 15 mm to 54 mm nominal

diameters to assist the designer.

Answer. 15 mm 0.107 kgs

, 22 mm 0.311 kgs

, 28 mm 0.624 kgs

, 35 mm 1.12 kgs

, 42 mm 1.881 kgs

,

54 mm 3.801 kgs

.

8. Calculate the water velocity in a 42 mm copper pipe carrying 1.52 kgs

at 75oC.

Answer. 1.264 kgs

.

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Gas

9. Find the flow rate of natural gas, methane, in a 15 mm copper pipe at a pressure loss rate of

12.5 Pam

.

Answer. 0.49 ls.

10. The pressure loss rate available for a gas supply installation is 8 Pam

. Copper pipe is to be

used. Calculate the gas volume flow capacity of pipes from 22 mm to 54 mm nominal

diameter.

Answer. 22 mm 1.13 ls, 28 mm 2.3 l

s, 35 mm 4.19 l

s, 42 mm 7.11 l

s, 54 mm 14.56 l

s.

Heating systems

11. Calculate the water mass flow rates needed for LTHW and MTHW heating systems in

order to transfer 3.5 kW and 420 kW. State which system would be used for each heat load.

Answer. For LTHW and 3.5 kW, M 0.07 kgs

; for LTHW and 420 kW, M 8.345 kgs

; for HTHW

and 3.5 kW, M 0.027 kgs

; Ffor HTHW and 420 kW, M 3.296 kgs

.

12. Find a suitable copper pipe diameter for a LTHW heating system to transfer 25 kW

from the boiler to a system of heat emitters if the pressure loss rate is not to exceed 750 Pam

and

the water velocity is not to be above 1 ms

. State the actual pressure loss rate and water velocity.

Answer. M 0.497 kgs

, 28 mm pipe, ∆𝑝𝑙

330 Pam

, v 0.941 ms

.

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13. District heating is to have a total connected heat load of 550 kW using a MTHW system

having a flow temperature of 150oC and a return of 120oC. Water velocity can be up to 3 ms

in

the underground distribution mains. The pressure loss rate is not to exceed 750 Pam

. If copper

pipe is to be used, what would be the appropriate size, actual pressure loss rate and water

velocity?

Answer. M 4.316 kgs

, 54 mm, ∆𝑝𝑙

630 Pam

, v 2.11 ms

14. The air conditioning system in a 20-storey office block is to comprise of air handling

plants and a basement boiler room. A total connected load of 100 kW was calculated.

Compare the diameters of LTHW heating system pipes with air ducts that would be needed

to transport the heating capacity vertically through the building. State how the design engineer

would configure the heating service to minimise the spaces occupied by the distribution

services. Maximum water velocity is to be 1 ms

. Air velocity is not to exceed 8 ms

.

Answer. For table X copper pipes, LTHW M 1.987 kgs

, d 54 mm, ∆𝑝𝑙

150 Pam

, v 0.96 ms

. For

galvanised metal duct, M 8.235 kgs

, Q 7.331 m3

s, d 1.1 m, ∆𝑝

𝑙 0.475 Pa

m, v 7.72 m

s. Distribute the

air handling plant around the building to minimise air duct runs and supply each plant with

LTHW pipework.

15. Calculate the pump and fan energy consumptions to operate LTHW or a ducted air

heating system where the boiler plant is 75 m from the heat load of 75 kW. Overall electro-

mechanical efficiency of the pump and fan is 65%. Water velocity can be up to 2 ms

and air

velocity up to 10 ms

. Frictional resistance of the pipeline fittings amounts to 25% of the length

of straight pipe and that for the air duct is 75% of the duct length.

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Answer. For table X copper pipe, LTHW, M 1.49 kgs

, d 35 mm, ∆𝑝𝑙

840 Pam

, v 1.83 ms

, pump

head H 157.5 kPa, pump power consumption 370.3 W. For galvanised steel air duct, Q 5.498

m3

s, d 0.9 m, ∆𝑝

𝑙 0.75 Pa

m, v 8.64 m

s, fan pressure rise H 196.875 Pa, fan power consumption

1.665 kW.

Thermal storage

16. Discuss why thermal storage is needed in heating and cooling services installations and

list the principal methods used.

17. A living room has an average rate of heat loss of 2.2 kW during a winter day while

occupied between 07.00 hours and 23.00 hours. An electrically charged off-peak storage

heater is to be installed to maintain comfort conditions. The charge period is 23.00 hours to

07.00 hours. Calculate the input power and the total energy storage required for the heater.

Answer. Stored energy 35.2 kWh, heater input power 4.4 kW.

18. A building having an average rate of daily heat loss of 15 kW between 07.00 hours and

23.00 hours is to be heated from a hot water storage tank operating between 85oC and 60oC.

The tank has electric immersion heaters operating between 23.00 hours and 07.00 hours.

Calculate the storage tank size needed, heater power and quantity of heat stored in MJ.

Answer. Storage capacity 864 MJ, heater power 30 kW, tank needs to be 2.907 m × 2.907 m

× 1 m high.

19. A 230 kW refrigeration compressor system chills water from 12oC to 7oC in an air

conditioning system. The compressor is not to cycle on/off more than four times per hour.

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During mild weather the building cooling load is 100 kW. Heat gains to the stored chilled

water amount to 15% of the cooling energy used. Calculate a suitable design for an

intermediate chilled water storage tank.

Answer. Cooling load 115 kW, compressor runs for 30 minutes per hour for four runs of 7.5

minutes each, chilled water storage tank size is 4.44 m × 4.44 m × 1 m.

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11 Air duct acoustics

Acoustic knowledge

1. Which is the smallest increment of sound pressure level detectable by the human ear?

1. 1 W/m2.

2. 1 bel.

3. 60 bel.

4. 100 N/m2.

5. 1 decibel.

2. What does the building services engineer do with noise?

1. Ignores it.

2. Passes any problem to a specialist.

3. Controls it to acceptable standard in occupied spaces.

4. Does not select plant that generates noise.

5. Alters the use of the building to avoid any noise problem.

3. What generates noise for the building services engineer?

1. Potentially everything the engineer can put into a building.

2. Only reciprocating machines.

3. Poorly designed and built engineering components.

4. The external environment.

5. All mechanical service plant and distribution systems.

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4. What is the unit of sound?

1. Pascal.

2. Watt.

3. Decibel.

4. Bell.

5. Bel.

5. Which is correct for sound units?

1. 1 bel is the sound level of an international standard bell ring.

2. 1 bel of sound pressure is very loud.

3. 1 dB is the smallest increment of sound pressure detectable by the ear.

4. Fractions of decibels are always counted.

5. Bel units are only used for specific frequencies.

6. How is acoustic energy created?

1. No such thing as acoustic energy.

2. Molecular vibration creates sound.

3. Physical vibration of a machine.

4. Magnetic resonance radiates sound waves.

5. A small proportion of the electrical or primary fuel input to a machine converts into

acoustic energy in watts.

7. What happens to audible range during human life?

1. No significant change.

2. Hearing sensitivity to volume improves with ageing.

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3. Ability to hear low frequency sounds deteriorates with ageing.

4. Human ear becomes less able to hear higher frequencies with increasing age.

5. Frequency range increases with age.

8. About how much reduction in hearing occurs during human life?

1. Hearing ability improves with age.

2. 100 dBA at retirement age.

3. Almost nothing with ageing.

4. 20 dB loss is common.

5. Maximum of 5 dB.

9. Explain the meaning of SWL:

1. Selective wind loading.

2. Sound wind level.

3. Sound watts level, meaning power.

4. Sound pressure level, meaning energy.

5. Sound watts loudness, meaning loudness power.

10. How much acoustic power is experienced within buildings?

1. 10% of electric motor power becomes acoustic energy.

2. Around 10 W/m2 floor area.

3. Above 1 kW.

4. Always below 500 W.

5. Less than 1 W.

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11. Where does sound energy not come from?

1. Atmospheric wind.

2. Dynamic mechanical equipment.

3. Harmonic frequencies in electrical systems.

4. Building materials.

5. Information technology equipment.

12. Which is not a harmonic frequency?

1. Alternating current 50 Hz.

2. Every sound frequency.

3. 20 kHz fluorescent lamp.

4. Any audible frequency generated by an electronic item such as variable speed drive

controller of a fan or pump.

5. Refrigeration compressor rotational speed.

13. Which is not a frequency?

1. Complete rotations each second.

2. Alternating current sine wave.

3. Structure borne vibration sound.

4. Fan RPM.

5. Sound pressure.

14. Which flowing fluid may not cause noise?

1. Water falling down a drain pipe.

2. Compressed air discharging to the atmosphere.

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3. Steam discharging to the atmosphere.

4. Laminar flow inside pipes and ducts.

5. Open drain flow.

15. Which flowing fluid may not cause noise?

1. Turbulent eddy currents shearing from blunt objects within air ducts.

2. High pressure water in circulating pipe systems.

3. Airflow across an air conditioned room.

4. Air flow round a bend in an air duct.

5. Water flow through a heat exchanger.

16. Which is not relevant to a sound frequency of 1 kHz?

1. Low frequency that is uncomfortable for the human body.

2. Human ear is most sensitive to sounds around 1 kHz.

3. Critical frequency in acoustic design.

4. Low frequency that is not noticed by the human body.

5. A multiple of alternating current frequency.

17. List the sources of noise that could be found within an air conditioned building.

18. What is meant by noise?

19. State which items of mechanical services plant, equipment and systems within an

occupied building are not likely to create noise?

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20. Explain how sound travels from one location to another.

21. Explain what is meant by the term sound pressure wave.

22. Why is sound important?

23. What is sound?

1. Electromagnetic radiation.

2. Molecular vibration of solid materials.

3. Radio frequency waves.

4. Anything that causes an ear response.

5. Pressure waves.

24. Sound travels through air because it is:

1. Incompressible.

2. Supporting molecular vibration.

3. Compressible.

4. Inelastic.

5. Plastic.

25. Reference point for sound level measurement is:

1. Absolute zero sound.

2. Lowest audible level by a domestic animal.

3. Smallest sound detectable by human ear.

4. Zero atmospheric pressure as found in space.

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5. Inaudible level created in a test laboratory.

Addition of sounds

26. A fan which produces a sound power level of 83 dBA at 1000 hertz is within the same

plant room as a gas-fired boiler that produces a sound power level of 85 dBA at 1000 hertz.

Calculate the combined sound power level that could enter the air duct system.

Answer. 87 dBA.

27. A centrifugal fan which produces a sound power level of 88 dBA at 500 hertz is within

the same plant room as a refrigeration compressor that produces a sound power level of 88

dBA at 500 hertz. Calculate the overall sound power level within the plant room.

Answer. 91 dBA.

Attenuation

28. Write a technical report on the equipment and materials that are used to reduce noise

transmission between the plant and the occupants of a building. Include sketches and data on

typical products that are available to the designer.

29. Explain what is meant by the static insertion loss of an air duct silencer. State the types

and performance data of duct silencers that are available.

30. Explain how air duct systems attenuate fan noise.

31. State how lined and unlined air ducts reduce the transmission of sound.

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32. Obtain sound absorption data for a variety of building materials and acoustic linings for

air ducts from different sources. These can be used to update and expand the worksheet data

bank.

33. Sketch and describe the most effective locations for absorbent duct lining materials and

duct attenuators.

34. State why the whole of the available attenuation is not taken into account during the

design process.

35. Create a combined table of data to compare the attenuation provided by circular and

rectangular attenuators, a 25 mm thick duct lining and a 50 mm thick duct lining for a 900

mm × 600 mm air duct. A 2 m length of the duct is to be lined and this is to include one lined

bend. Discuss the relative merits of each of these methods of providing attenuation.

36. Explain why there are practical limits to the attenuation of air flow in ducts.

37. How is noise transmission from plant reduced?

1. Cannot be reduced, only contained within plant room.

2. Select quieter plant.

3. Seal plant room doors.

4. Locate plant room away from occupied rooms.

5. Flexible rubber and spring mountings.

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1. Porous sound absorbing materials.

2. Thicker concrete walls and floors.

3. Bolt refrigeration compressor to concrete slab.

4. Line plant room with lead.

5. Sit further away from it.

Basics

39. Should we be concerned with any linkage between the HM Government Carbon Plan

2011 and acoustics?

1. No, there is no connection.

2. Acoustic energy dissipates in porous materials and raises its temperature causing a

cooling load for the refrigeration system; yes we are concerned.

3. Only people create unwanted sound.

4. Noise reconverts back into useful energy.

5. Yes, noise means energy is used somewhere.

40. Explain how the sound field in an occupied room is perceived.

41. List the sources of a sound field in normally occupied rooms and spaces within air

conditioned buildings.

42. State all the plant, equipment and systems that provide an acoustic environment in

rooms.

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43. Explain how two or more sources of acoustic energy are combined mathematically.

44. Sketch and describe the ways in which acoustic energy is absorbed in an air ductwork

system serving an office.

45. Explain how sound enters, travels through, is attenuated by and escapes from, a ducted

air duct system.

Decibel

46. Which is the smallest increment of sound pressure level detectable by the human ear?

1. 1 W/m2.

2. 1 bel.

3. 60 bel.

4. 100 N/m2.

5. 1 decibel.

47. Explain why any decimal fraction of a decibel is not used in engineering design.

Design cases

48. A model C44 supply air centrifugal fan passes 6500 ls at a fan total pressure of 550 Pa.

The fan impeller runs at 14 Hz. The supply air ductwork system comprises of 8 m of lined

850 mm × 750 mm duct, one lined bend with turning vanes, no branches, two unlined bends,

20 m unlined duct, one duct end reflection. The diffuser does not generate any noticeable

sound power but is near the wall and ceiling junction, so directivity Q is 4. The target room is

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a lecture theatre for 250 people. The theatre is 30 m × 25 m and 6 m high. The nearest

recipient’s head is 3 m from a diffuser. The floor is carpeted. The ceiling has 15 mm

suspended acoustic tiles and 50 mm glass fibre matt. The walls are plastered brick. There are

no windows. Find the noise rating that is not exceeded in the theatre when empty and whether

it is suitable.

Answer. NR 35, yes.

49. A model AX66 600 mm diameter supply air axial flow fan passes 2000 ls at a fan static

pressure of 95 Pa. The fan impeller runs at 18 Hz. A circular attenuator is located downstream

of the fan. The supply air ductwork system comprises of 10 m of unlined straight 900 mm ×

700 mm duct from the fan to the first grille. The duct has a blank end and there are two

unlined bends in the duct. Air leaves the duct through a grille in the side of the duct. There is

no noise generation in the duct system or at the terminal grille. The ventilated office is 12 m ×

8 m and 3 m high. The nearest recipient’s head to the diffuser is at a distance of 1 m. The

floor is concrete, the ceiling is exposed 18 mm floor boards on timber joists and the walls are

plastered brick with 12 m2 of single glazing. Find the noise rating that is not exceeded at any

frequency for the occupied room and whether it is suitable.

Answer. NR 55, not suitable, more attenuation required or use a different fan.

50. An air conditioned food supermarket is 30 m × 30 m and 4 m high. The conditioned air

is supplied by a model CE45 centrifugal fan that passes 7500 ls at a fan static pressure of 390

Pa. The fan impeller runs at 21 Hz. The fan sound power levels are: 87 dB overall, 60 dB at

31.5 Hz, 55 dB at 63 Hz, 65 dB at 125 Hz, 72 dB at 250 Hz, 76 dB at 500 Hz, 83 dB at 1 kHz,

84 dB at 2 kHz and 74 dB at 4 kHz and 64 dB at 8k Hz. The supply air ductwork system

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comprises of 4 m of lined straight 900 mm × 900 mm duct, including two lined bends, and 12

m of the same size of unlined duct between the fan and the first air outlet grille. The duct has

a blank end. There is no noise generation in the duct system or at the terminal grille. The

nearest recipient’s head to the diffuser is at a distance of 2 m. Directivity Q is 2. The floor has

plastic tiles on concrete, the ceiling is 15 mm acoustic tile with 50 mm mineral fibre

insulation and the walls are plastered brick. The single glazed shop window is 25 m long and

3 m high. Find the noise rating that is not exceeded at any frequency in the supermarket and

whether it is suitable.

Answer. NR 20, highly suitable.

51. An air conditioned library is 25 m × 35 m and 5 m high. The conditioned air is supplied

by a model CE86 centrifugal fan that passes 4500 ls at a fan static pressure of 275 Pa. The fan

impeller runs at 15 Hz. The fan sound power levels are: 77 dB overall, 40 dB at 31.5, Hz 45

dB at 63 Hz, 55 dB at 125 Hz, 62 dB at 250 Hz, 66 dB at 500 Hz, 73 dB at 1 kHz, 74 dB at 2

kHz, 64 dB at 4 kHz and 60 dB at 8K Hz. The supply air ductwork system comprises of 10 m

of 800 mm × 700 mm duct, three bends, and a blank duct end and supply air diffusers. There

is no noise generation at the diffusers. Directivity Q is 2. The nearest recipient’s head to a

diffuser is at a distance of 2 m. The floor has carpet tiles with underfelt on concrete, the

ceiling is 15 mm suspended acoustic tiles with roof insulation and the walls are plastered

brick. There are single glazed windows amounting to 8 m long and 2 m high. Find the noise

rating that is to be provided in the library. Enter the data onto a working copy of the

worksheet and calculate how to achieve the required acoustic design criteria.

Answer. Maximum NR allowed in a library is NR 35. 1 m of lined duct reduces higher

frequencies to below NR 30.

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52. A model CE14 extract centrifugal fan removes six air changes per hour from a hotel

lounge room. The lounge is 8 m × 6 m and 3 m high. The fan static pressure is 130 Pa and the

fan impeller runs at 17 Hz. The fan sound power levels are: 67 dB overall, 30 dB at 31.5 Hz,

35 dB at 63 Hz, 45 dB at 125 Hz, 52 dB at 250 Hz, 56 dB at 500 Hz, 63 dB at 1 kHz, 64 dB at

2 kHz, 54 dB at 4 kHz and 50 dB at 8kHz. The extract air ductwork system comprises of 3 m

of 600 mm × 400 mm duct, one bend, a blank duct end and an extract air grille. The nearest

recipient’s head to the grille is at a distance of 1 m. Directivity Q is 8. The floor is carpeted,

the ceiling is hard plastered to the equivalent of a plastered wall and the walls are plastered

brick. There are single glazed windows amounting to 3 m long and 2 m high. Fabric curtains

and soft furniture have a surface area of 10 m2. Find the noise rating that is to be provided in

the lounge. Enter the data onto a working copy of the worksheet and calculate how to achieve

the required acoustic design criteria.

Answer. 1 m of lined duct reduces the critical 500 Hz SPL to NR 35 suitable for a lounge.

53. An 1860 heritage building is typical of its era. No permanent structural alterations are

allowed by the Heritage Council. The owner asks a consultant to advise on how to lower the

noise level in the restaurant. The room is 35 m × 20 m and 5 m high. Two long walls are bare

granite. End walls are all single glazing. Floor is bare polished timber on foundation walls.

Roof structure is bare varnished timber planks on timber frame with no thermal insulation,

and corrugated iron sheet; take its absorption data as for the floor. 150 patrons can be seated

and served by eight staff. There is no noise entering from outdoors or the kitchen. Chairs

scraping the floor are annoying. Background white noise, no distinct frequencies, appears

loud.

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A model D45 supply air centrifugal fan passes 10000 ls at a fan total pressure of 700 Pa.

The fan impeller runs at 12 Hz. The air conditioning supply air duct system comprises of 30

m of 950 mm × 950 mm duct, four bends and four duct end reflection. The final diffuser does

not generate any noticeable sound power but is near the wall and ceiling junction, so

directivity Q is 4. The nearest recipient’s head is 3 m from a diffuser. Use file dbduct.xls to

calculate the aural environment when the restaurant is full and decide on the consultant’s

advice.

Answer. Without duct attenuation the restaurant experiences just over NR 60 and this is

unacceptable; NR 40 is needed. A serious problem is the harshness of the room, every surface

is hard, bouncing sound and creating multiple echoes with a reverberation time of 2.5 s at

1000 Hz, the most noticeable for listening. Hanging 250 m2 of acoustic panels from the

ceiling and 100 m2 of drapes to hide some of the stone wall halves reverberation time but does

not reduce room sound below NR 60; additionally lining 3 m of duct lowers the room to NR

35; this would greatly improve the aural environment without permanently losing the interior

heritage style.

Fan sound power

54. Find the anticipated fan sound power level when a centrifugal fan is passing 1750 ls at a

fan static pressure of 190 Pa for the range of frequencies from 31.5 Hz to 8000 Hz.

Answer. 86, 83, 80, 78, 74, 70, 65, 58, 48 dB.

55. Find the anticipated fan sound power level when an axial flow fan is passing 3500 ls at a

fan static pressure of 100 Pa for the range of frequencies from 31.5 Hz to 8000 Hz.

Answer. 83, 82, 81, 79, 77, 75, 72, 69, 65.

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Human ear

56. Explain how we ‘hear’ sounds.

57. State the range of frequencies that are detectable by the human ear and the frequencies

that are used in acoustic design calculations. State the reasons for these two ranges being

different, if they are.

58. How are noises related to human ear response?

1. Humans respond to sound power level within a range of audible frequencies.

2. Humans respond to loudness produced over a range of audible frequencies.

3. Sound pressure levels are added to create an overall relationship to ear response.

4. Sound power levels are added to create an overall relationship to ear response.

5. Loudest sound at any frequency is taken as ear response.

59. Presbycusis is:

1. Hearing loss due to long term exposure to noise above 90 dBA.

2. Hearing loss due to ear disease.

3. Normal deterioration in hearing due to ageing.

4. A church presbytery committee.

5. Temporary shift in hearing ability from exposure to high industrial noise levels above

95 dBC.

60. Hearing range is:

1. 20 Hz to 20 kHz.

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2. 2 Hz to 20 MHz.

3. 200 Hz to 200 MHz.

4. Infinitely wide.

5. 2 kHz to 20 MHz.

61. What is noise?

1. Sound.

2. Acoustic power.

3. Unwanted sound.

4. Age-related sound.

5. Traffic, aeroplanes, pneumatic drills, fans, refrigeration compressors.

62. How do we judge sound?

1. Absolute measurement.

2. Comparing a sound with absolute zero sound level.

3. Relatively.

4. Subjectively.

5. Qualitative judgement.

63. What is sound?

1. Anything humans hear.

2. Electrical signals in the brain responding to ear drum vibration.

3. Noise.

4. Annoyance created by music or pneumatic road drills.

5. Radiated energy in audible frequencies.

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64. Presbycusis is:

1. Exposure to above 100 dBA.

2. Happens when listening to loud music.

3. Normal deterioration in hearing due to ageing.

4. Presbytery.

5. Improvement in hearing ability.

65. Hearing range is:

1. Infinite.

2. 2 Hz to 20 Hz.

3. 200 Hz to 200 MHz.

4. 0 to 120 dBA.

5. 20 Hz to 20 kHz.

66. What is noise?

1. Any sound.

2. Acoustic power measured in watts.

3. Any traffic.

4. Age-related sound.

5. Excess sound.

67. How do we judge sound?

1. We don’t.

2. Comparing a sound with absolute zero sound level.

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3. On some sort of scale.

4. By its annoyance.

5. Qualitatively.

Machinery noise

68. An eight cylinder formula one car engine peaks at 20000 RPM. One of the sound

frequencies it produces is:

1. 8 Hz.

2. 20 kHz.

3. 400 Hz.

4. 2000 Hz.

5. 2667 Hz.

69. A gas turbine rotates at 60000 RPM and has 50 blades on its largest diameter. One of

the sound frequencies it produces is around:

1. 50 kHz.

2. 50 Hz.

3. 5000 Hz.

4. 60 kHz.

5. 20 kHz.

70. An eight cylinder formula one car engine peaks at 20000 RPM. One of the sound

frequencies it produces is:

1. 2000 to 3000 Hz.

2. Millions of Hz.

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3. 2 kHz.

4. 40 Hz.

5. 20000 Hz.

71. A twelve cylinder Italian formula one car engine peaks at 15000 RPM. One of the

sound frequencies it produces is:

1. 3 kHz.

2. Something very annoying.

3. Music to an engineer.

4. Horrible scream.

5. 20000 Hz.

72. A gas turbine rotates at 60000 RPM and has 50 blades on its largest diameter. One of

the sound frequencies it produces is around:

1. 50 kHz.

2. 50 Hz.

3. 5000 Hz.

4. 60 kHz.

5. 20 kHz.

73. Which item of plant does not normally create noise?

1. Fans and pumps.

2. Refrigeration compressors.

3. Fired water heaters.

4. Air compressors.

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5. Piped systems.

74. Which frequency range is audible?

1. 2 kHz to 200 kHz.

2. Infinite range.

3. 200 kHz to 1 MHz.

4. 0 Hz to 10000 Hz.

5. 20 Hz to 20 kHz.

75. A noisy machine on a plant room base:

1. Radiates direct sound in straight lines only.

2. Fills the plant room with noise.

3. Sounds equally noisy from all directions.

4. Produces a spherical field of sound waves.

5. Produces a hemispherical sound field.

76. A noisy machine on a plant room concrete floor:

1. Has no sound directivity.

2. May direct sound more strongly in a particular direction.

3. Sends direct sound field through the floor.

4. Only creates a reverberant sound field.

5. Gains a benefit from sound energy absorbed by the floor.

77. What happens if an air conditioning fan is run at its natural frequency of vibration, say,

100 RPM?

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1. Nothing special.

2. Fan can continue to run at this speed indefinitely.

3. It is the ideal speed for the fan as it produces maximum aerodynamic efficiency.

4. Fan cannot vibrate.

5. Fan vibration can cause destruction.

Noise and vibration

78. Explain, with the aid of sketches, ways in which the noise and vibration produced by the

mechanical and electrical services of a building can be reduced before they become a

nuisance for the building’s users.

79. Explain how sound energy is dissipated into the environment.

80. What does natural frequency of vibration mean?

1. Damped vibration.

2. Strike a guitar string and it vibrates at up to four times its natural frequency depending

on volume of sound box.

3. Bounce a coil spring and it vibrates at its natural frequency of vibration.

4. A frequency mechanically forced upon an item, such as by a motor.

5. A material never vibrates at this frequency.

Noise rating

81. Which does NR stand for?

1. Noise resonance.

2. Normal rating.

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3. No resonance.

4. Noise ratification.

5. Noise rating.


1. No resonance.

2. Nocturnal rating.

3. Nil reverberation.

4. Naval rating.

5. Noise rating.








1. Loudest sound at any one frequency determines maximum discomfort.

2. Loudest sound at 1 kHz defines maximum discomfort.

3. Rating discomfort is entirely subjective and varies widely.

4. Ear responds most to widely spaced sound waves.

5. Sound loudness at specific frequencies is related to ear response at the same

frequencies.

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85. How is noise related to human ear response?

1. Noise rating curves represent human ear response to the range of audible frequencies.

2. Sounds are equally loud to the human ear at any audible frequency.

3. Loudness is not related to sound pressure level.

4. Loudness relates solely to sound power level.

5. Ear response is a flat line over all frequencies.


1. Noise rating curves specify equal sound power level for all frequencies.

2. Noise rating curves specify equal sound pressure level for any frequency.

3. Noise rating curves specify equal loudness for a range of frequencies.

4. Noise ratings are subjectively assessed.

5. Machines are given a noise rating value.

87. Which of these is not correct about noise rating?

1. Critically quiet areas such as a recording studio are designed to NR 20.

2. NR 60 to NR 80 are found in heavy industrial facilities.

3. Office environments require external traffic and mechanical services noise to be

controlled to around NR 40.

4. NR 80 is not suitable for a library.

5. Noise rating is percentages.

88. Explain how noise rating curves relate to the response of the human ear and are used in

the design of mechanical services plant and systems.

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See chapter explanation.

Noise rating design

89. The centrifugal fan in an air handling plant produces the noise spectrum shown in table

1 within an office. Calculate the sound pressure levels for noise ratings NR 35, NR 40, NR

45, NR 50 and NR 55 and plot the noise rating curves for the frequency range 31.5 Hz to 8

kHz. Plot the room sound pressure levels on the same graph and find which noise rating is not

exceeded.

Table 1 Noise spectrum in question 89

Frequency f Hz 31.5 63 125 250 500 1 k 2 k 4 k 8 k

Room SPL dB 30 35 32 40 42 31 28 20 10

Answer. NR 40 is not exceeded in the room.

90. A model XT45 water chiller is to be located within a plant room on the roof of a hotel in

a city centre. The plant room is 12 m long, 10 m wide and 3 m high. The room directivity

index is 2. The plant operator will normally be 1 m from the noise source. The floor is

concrete; the roof is lined internally with a 50 mm polyester acoustic blanket with a metallised

film surface. The plant room walls are 115 mm brickwork. There are no windows. The water

chiller manufacturer provided the sound power levels as 100 dB overall, 74 dB at 63 Hz, 89

dB at 125 Hz, 95 dB at 250 Hz, 97 dB at 500 Hz, 99 Hz at 1 kHz, 97 dB at 2 kHz and 90 dB

at 4 kHz.

(a) Check that the correct data are entered onto the working copy of the original

worksheet file dbplant.wks and find the noise rating that is not exceeded within the

plant room. (NR 80)

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(b) The plant room has three external walls. The nearest openable window in nearby

buildings is at a distance of 15 m from a plant room wall. There is no acoustic barrier

between a plant room wall and the recipient’s window. The directivity index for the

outward projection of sound is taken as 3 dB. Find the noise rating at the recipient’s

window and state what the result means. (NR 25, no intrusive noise from the chiller)

(c) A corridor adjoins the plant room. The target sound space, an office, is on the

opposite side of the corridor. The corridor is 10 m long, 1 m wide and 3 m high. It

has a room directivity index of 2, a carpeted concrete floor, plastered brick walls and

a plasterboard ceiling. The common wall between the plant room and the corridor is

10 m long, it is constructed with 115 mm plastered brickwork and it does not have a

door. There are no windows. There is no other sound barrier. Find the noise rating

which would be found at a distance of 0.5 m from the plant room wall while within

the corridor. (NR 45)

(d) The target office is 10 m long, 10 m wide and 3 m high. The room directivity index

is 2. The nearest sedentary occupant of the office will be 1 m from the corridor wall.

The floor has pile carpet, the walls are plastered brick and there is a suspended

ceiling of 15 mm acoustic tile and 50 mm glass fibre matt. The office has four 2 m ×

2 m single glazed windows on two external walls. The office wall that adjoins the

corridor is 115 mm plastered brickwork and it has one 2 m2 door into the corridor.

Find the noise rating, NR, and sound pressure levels, SPL dB, that are experienced in

the target office. State what effect the office and plant room doors will have on the

noise rating in the target room. Recommend appropriate action to be taken with these

doors. (NR 20 when doors have equal sound reduction to the walls, have airtight

seals and are closed)

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91. A centrifugal fan is located within the basement plant room of an office building. The

plant room is 8 m long, 6 m wide and 3 m high. The room directivity index is 2 and the

plant operator will normally be 1 m from the noise source. The floor and ceiling are

concrete, there are four 230 mm brick walls and one acoustically treated door. There are no

windows in the plant room. The sound power levels of the fan are: 86 dB overall, 64 dB at

63 Hz, 66 dB at 125 Hz, 72 dB at 250 Hz, 80 dB at 500 Hz, 86 Hz at 1 kHz, 82 dB at 2

kHz and 77 dB at 4 kHz.

(a) Find the noise rating that is not exceeded within the plant room. (NR 80)

(b) A corridor and staircase connect the plant room to the reception area of the building.

The corridor is 6 m long, 1 m wide and 3 m high. It has a room directivity index of 2.

The corridor has a concrete floor, plastered brick walls and a plasterboard ceiling.

The common wall between the plant room and corridor is 2 m long. The sound

reduction index of the plant room door is 20 dB at each frequency from 125 Hz to 4

kHz. There is no other sound barrier. Find the noise rating that would be found at a

distance of 1 m from the plant room in the corridor. (65 dB due to sound escape

through door)

(c) The reception area is 12 m long, 8 m wide and 3 m high. The room directivity index

is 2. There are 10 m2 of single glazed windows in reception. There is a door at the top

of the staircase down to the plant room. The stairs door is 1 m wide, 2 m high and it

has a sound reduction index of 20 dB at each frequency from 125 Hz to 4 kHz. The

nearest occupant will be 1 m from the stairs door. The floor has thermoplastic tiles

on concrete, the walls are plastered brick and there is a plasterboard ceiling. Find the

noise rating which is not exceeded in Reception. (NR 35)

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92. Oil-fired hot water boilers are located in a plant room in the basement of an exhibition

and trade centre building in a city centre. The plant room is 10 m long, 10 m wide and 5 m

high. The room directivity index is 2. The floor, walls and ceiling are concrete. There are no

windows. The reference sound power level of the boiler plant is 88 dBA.

(a) Find the anticipated spectral variation in the sound power level for the frequency

range from 63 Hz to 4 kHz from table 15.4 and figure 15.1 Building Services

Engineering 6th edition, enter the data onto the worksheet and find the noise rating

that is not exceeded within the boiler plant room. (NR 75)

(b) The plant room has three 100 mm concrete external walls. The nearest recipient

can be 1 m from the external surface of a boiler plant room wall. There is no

acoustic barrier between a plant room wall and a recipient. The directivity index

for the outward projection of sound is taken as 3 dB. Find the noise rating at the

nearest recipient’s position and state what the result means. (NR 45, equivalent to

the background noise level in a corridor)

(c) A hot water pipe and electrical cable service duct connects the boiler plant room

to other parts of the building. The concrete-lined service duct is 30 m long, 2 m

wide and 1 m high. Both ends of the service duct have a 100 mm concrete wall.

Calculate the noise rating within the service duct at its opposite end from the

boiler plant room. (NR 35)

(d) A conference room 115 mm brick wall adjoins the service duct at the furthest end

from the boiler plant room. The conference room is 12 m long, 10 m wide and 4

m high. The room directivity index is 2. The nearest sedentary occupant will be

0.5 m from the service duct wall. The floor has pile carpet, the walls are plastered

brick and there is a suspended ceiling of 15 mm acoustic tile and 50 mm glass

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fibre matt. There are no windows. Find the noise rating that is produced in the

conference room by the boiler plant. (NR 20, there is no intrusive noise)

93. A four-pipe chilled and hot water fan coil unit is located within the false ceiling space

above an office in an air conditioned building. Conditioned outdoor air is passed to the fan

coil unit through a duct system. The office is 5 m long, 4 m wide and 3 m high. The room

directivity index is 2. The office has a concrete floor with thermoplastic tiles and 115 mm

plastered brick walls. The 700 mm deep suspended ceiling has 12 mm fibreboard acoustic

tiles, recessed fluorescent luminaires, ducted supply and return air with a supply air diffuser, a

return air grille and a concrete ribbed slab for the floor above. The office has a double glazed

window of 2 m × 2 m. The reference sound power level of the fan coil unit is 85 dBA. Enter

the ceiling space as the plant room and bypass the intermediate space data as directed.

(a) Find the anticipated spectral variation in the sound power level of the fan coil unit for

the frequency range from 63 Hz to 4 kHz from table 15.4 and figure 15.1 Building

Services Engineering 6th edition. Enter the data onto the worksheet and find the noise

rating that is not exceeded within the ceiling space above the office. (NR 60)

(b) Find the noise rating that is not expected to be exceeded within the office at head

height. Assume that the sound reduction of the acoustic tile ceiling is maintained across

the whole ceiling area. (NR 40)

(c) Sketch a cross-section of the fan coil unit installation and identify all the possible noise

paths into the office. (Through the supply and return air ducts, noise radiation from the

outer case of the fan coil unit, from the ceiling space through ceiling tiles, light fittings,

noise break-in from the ceiling space into the supply and return air ducts and then into

the office, structurally transmitted vibration from the fans, main air handling plant noise

through the outside air duct to the fan coil unit)

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(d) List the ways in which the potential noise paths into the office can be, or may need to

be, attenuated. (Acoustic lining in the outdoor air, supply air and return air ducts, anti-

vibration rubber mounts for the fan coil unit and the fan within it, acoustic lining within

the fan coil unit, acoustic blanket above the recessed luminaires and above the ceiling

tiles)

Plant room calculations

94. An axial flow fan has an overall sound power level of 78 dB. The plant room has a

reverberation time of 2.5 seconds and a volume of 240 m3. Calculate the plant room

reverberant sound pressure level.

Answer. 72 dB.

95. A fan and a refrigeration compressor are located within the same plant room. The

manufacturers state that the sound power levels are 79 dB for the fan and 80 dB for the

compressor. Calculate the combined sound power level in the plant room.

Answer. 82 dB.







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97. An air conditioning centrifugal fan has an overall sound power level SWL of 75 dBA.

The fan is to be installed centrally within a plant room that has a room absorption constant R

of 12 m2. Calculate the sound pressure level that will be produced close to the fan, in the plant

room at 1000 Hz when the fan is operating, and also generally within the room.

Answer.r 100 mm SPL 87 dB; r 1 m SPL 71 dB.

98. A 900 mm diameter axial fan is to be installed on the concrete floor of an 8 m × 4 m × 3

m high plant room. The fan sound power level at 1000 Hz is 89 dB. The room absorption

constant R at 1000 Hz is 8 m2 and the reverberation time is 0.4 s. Calculate the room sound

pressure level at a radius of 300 mm from the fan, and the reverberant room sound pressure

level.

Answer. Directivity Q 2, r 0.5 m SPL 92 dB, reverberant SPL 79 dB.

99. A reciprocating water chilling refrigeration compressor has an overall sound power

level of 92 dBA. It is to be located within a concrete and brick plant room that has a

reverberation time of 1.8 s and a volume of 250 m3. Calculate the plant room reverberant

sound pressure level.

Answer. 84 dBA.

100. An air handling plant has an overall sound power level of 81 dB. The plant room has an

external wall of 10 m2 that has an acoustic attenuation of 35 dB and ventilation openings

having a free area of 3 m2. The windows of residential and office buildings are at a distance of

12 m from the plant room wall. Calculate the external sound pressure level at the windows

and recommend what, if any, attenuation is needed at the plant room.

Answer. Through the wall SPL2 19 dB; through air vent 49 dB; open air vent causes noise to

bypass the attenuation of the wall and may need acoustic louvres or an acoustic barrier.

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101. A forced draught gas-fired boiler has an overall sound pressure level of 96 dB. The

boiler plant room has an external wall of 60 m2 that has an acoustic attenuation of 25 dB and

two louvre doors to admit air for combustion. Calculate the external sound pressure level at a

distance of 20 m from the plant room wall. State your recommendations for the attenuation of

the boiler and the plant room.

Answer. Through the wall SPL2 47 dB; through air vents in doors 59 dB; open air vent causes

noise to bypass the attenuation of the wall; burner needs an acoustic enclosure.

Reverberant and direct sound fields

102. Explain the difference between direct and reverberant sound fields.

103. State what is meant by reverberation time.

104. What is a reverberant sound field?

1. Sound transmitted over a large distance.

2. Sound passing through a structure.

3. What remains within an enclosure after source energy is absorbed by the building

structure.

4. Reflected sound.

5. Sound pressure level measured in an anechoic laboratory chamber.

105. Explain what is meant by direct and reverberant sound fields.

106. Direct sound field:

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1. Increases in intensity further from the source.

2. Remains at a constant noise at any distance from the source while the hearer remains in

the source plant room.

3. Decreases linearly with distance from source.

4. Falls with the inverse square of the distance from the sound source.

5. Doubles the value of the reverberant sound field.

107. Which of these is not correct about absorbing sound energy?

1. Dense materials absorb acoustic energy efficiently.

2. Highly porous materials are good sound absorbers.

3. The denser the material mass, the greater the sound absorption.

4. A 75 mm air cavity behind a sheet of plasterboard is a good sound absorber.

5. A plastered brick wall has a low sound absorption coefficient.

108. Which is not correct about reverberation time?

1. When short, below a second, room seems lively.

2. Long reverberation time causes room to sound noisy and causes echoes.

3. A lecture theatre needs a short reverberation time.

4. A large volume car manufacturing building has a long reverberation time.

5. When short, below a second, room seems dull.

109. Which is not correct about an anechoic chamber?

1. Used to measure sound power level from acoustic sources such as fans and

compressors.

2. Must have no reverberant sound field.

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3. Lined with fully absorbent foam wedges.

4. Sounds perfectly dull.

5. Used to measure reverberant field sound pressure level from acoustic sources such as

fans and compressors.

110. Which is not correct for sound fields?

1. Direct sound from a source.

2. Anywhere a source provides sound power level.

3. An enclosure having a reverberant sound pressure level, SPL.

4. Anywhere receiving sound pressure level.

5. Enclosure having a reverberant sound field and directly transmitted sound pressure from

a source.

111. Which does not describe a direct sound field?

1. Sound transmitted over an outdoor distance.

2. Sound pressure level measured within an anechoic laboratory chamber.

3. Sound pressure level created only by the source.

4. Reflected sound.

5. Line of sight transmitted sound.





structure.

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4. Reflected sound.


113. Which is correct for sound reverberation time?

1. Time between echoes.

2. How long a sound level continues.

3. Time lag between directly received sound and reverberated sound.

4. Time for a sound to decrease to zero within a room after source is switched off.

5. Time taken for a sound to decrease by 60 dB.

114. A sound pressure level of 30 dB is:

1. Very loud.

2. Loud noise.

3. Acceptable for an office environment.

4. Almost imperceptible.

5. Taken as zero base level.

115. Reverberation time is:

1. Typically one minute or longer.

2. A few seconds.

3. Produced by sound bouncing from multiple soft surfaces.

4. Not important.

5. Only needed in concert halls.


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1. Always many minutes.

2. Less than 0.001 s.

3. Uncomfortably loud noise.

4. Produced by sound bouncing from multiple hard surfaces.

5. Inaudible sound.


1. Only heard in a cave.

2. An echo.

3. Noise generated by a reciprocating machine.

4. Not heard in a lounge room.

5. Due to drumming on sides of sheet metal air ducts.

118. Which is not correct about reverberation time:

1. Below a second, room seems lively.

2. Long reverberation time causes room to sound noisy and echoes.

3. A lecture theatre needs a short reverberation time.

4. A large volume car manufacturing building has a long reverberation time.

5. When short, below a second, room seems dull.

119. Which is correct about an anechoic chamber?

1. Used to measure reverberant sound field.

2. Lined with hard surface materials to contain sound within room.

3. Has fully sound-reflecting surfaces.

4. Used to measure reverberant sound field.

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5. Used to measure direct sound field.


1. Lined with 100% absorbing surfaces.

2. Only has walls lined with sound absorbing foam wedges.

3. Not used to measure sound power level of a sound source.

4. Used to analyse sound frequencies in a building.

5. Must have a concrete floor.


1. Cannot find realistic sound output from a machine.

2. One with a concrete floor, lined wall and lined ceiling, used to measure outdoor realistic

sound output from s source.

3. Only used for sound recording.

4. Used for testing musical instruments.

5. Has multiple echoes.


1. Used to measure sound power level from acoustic sources such as fans and

compressors.

2. Must have no reverberant sound field.

3. Lined with fully absorbent foam wedges.

4. Sounds perfectly dull.

5. Used to measure reverberant field sound pressure level from acoustic sources such as

fans and compressors.

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1. It has no reverberant sound field.

2. Its walls, floors and ceiling are perfect sound absorbers.

3. Allows a spherical sound field from a centrally placed source.

4. Used for measuring reverberation time from a test item.

5. It is a laboratory to measure sound power level of an item.

Room absorption

124. What do room surfaces do to sound fields?

1. Do not restrain the sound field.

2. Radiate sound from the room.

3. Reflect sound waves.

4. Create noise.

5. Nothing significant.

125. How do materials absorb sound energy?

1. Molecular vibration.

2. Physical vibration to dissipate sound energy.

3. Equally at all sound pressure levels.

4. Only by means of holes and cracks in the material.

5. Building materials cannot absorb sound.

126. How do materials absorb sound energy?

1. All materials absorb sound energy equally.

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2. Only porous materials have any effect.

3. Selectively at different sound frequencies.

4. Selectively at different sound pressure levels.

5. Brick only absorbs sound at one frequency.

127. Which of these is not correct about absorbing sound energy?

1. Dense materials absorb acoustic energy efficiently.

2. Highly porous materials are good sound absorbers.

3. The denser the material mass, the greater the sound absorption.

4. A 75 mm air cavity behind a sheet of plasterboard is a good sound absorber.

5. A plastered brick wall has a low sound absorption coefficient.

128. A plant room for a refrigeration compressor is 6m × 4m in plan and 3m high. It has four

brickwork walls, a concrete floor and a concrete roof. Select the surface absorption

coefficients for the frequency range 125 Hz to 4000 Hz. Calculate the room absorption

constant and the reverberation time for the plant room at each frequency. Do the calculations

manually and then enter the same data onto the worksheet to validate the results.

Answer.Reverberation time T 2.901 s at 125 Hz, 3.462 s at 250 Hz, 3.462 s at 500 Hz, 3.157 s

at 1 kHz, 2.752 s at 2 kHz and 3.253 s at 4 kHz.

Room sound pressure levels

129. What is sound?


2. Molecular vibration of solid materials.

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3. Radio frequency waves.

4. Anything that causes an ear response.

5. Pressure waves.

130. Sound travels through air because it is:

1. Incompressible.

2. Supporting molecular vibration.

3. Compressible.

4. Inelastic.

5. Plastic.

131. Sound travels through air in the form of:

1. Straight lines.


3. Sinusoidal alternating frequency.


5. Waves.

132. Sound does not cause:

1. Compression waves in air.

2. Physical vibration of glazing and thin steel sheet.

3. Variation of the barometric air pressure at the wave front.

4. Oscillation of the eardrum.

5. Stiff materials to vibrate.

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133. Sound does not require:

1. A receptive eardrum.

2. Elastic transfer medium.

3. Compressible transfer medium.

4. Stiff material to pass through.

5. Energy to create it.

134. Which is true of sound?

1. Energy is used to create it.

2. Heat and sound are mutually convertible.

3. No energy is needed to generate sound waves.

4. Sound energy can be usefully recovered.

5. Sound waves are temperature dependent.

135. Which is not true about sound reception?

1. Ear response.

2. Stimulation of brain to interpret into something meaningful.

3. Physical vibration of a microphone diaphragm to convert it into meaningful energy

pulses.

4. Nothing is needed as it just exists.

5. Sensitivity to very small variations in atmospheric pressure.

136. Reference point for sound level measurement is:

1. Absolute zero sound.

2. Lowest audible level by a domestic animal.

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3. Smallest sound detectable by human ear.

4. Zero atmospheric pressure as found in space.

5. Inaudible level created in a test laboratory.

137. Atmospheric sound pressure waves are measured by:

1. Vacuum chamber.

2. Absolute pressure units, Pa.

3. Frequency.

4. Speed in air.

5. Relative pressure units.

138. Creation of sound uses:

1. Natural forces from the atmosphere.

2. Mechanically produced force.

3. Radiation energy.

4. Nothing is consumed, only converted.

5. Wind pressure.

139. Sound waves repeat at a frequency due to:

1. Absorption by porous surfaces.

2. Wind forces.

3. Multiple sources of sound.

4. Passage of blades in a rotary machine such as a compressor, pump or turbine.

5. Variations in air pressure.

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1. Bouncing from hard surfaces.

2. Multiple passageways through porous materials.

3. Variable wind forces.

4. Air temperature variation.

5. Interference from radio frequency waves.

141. A single-storey office building has floor dimensions of 40 m × 30 m and a height of 3 m

to a suspended acoustic tile ceiling. The average height of the ceiling void is 1.5 m. A plant

room is adjacent to the roof void. There is a common plant room wall of 10 m × 1.5 m high in

the roof void. The sound pressure level in the plant room is expected to be 61 dB. The

reverberation time of the roof void is 0.6 s. The plant room wall adjoining the roof void has a

sound reduction index of 13 dB. Calculate the sound pressure level that is produced within the

roof void as the result of the plant room noise. Comment on the resulting sound pressure

level.

Answer.SPL in roof is 32 dB; the large volume and short reverberation time assist in

attenuating the plant room noise.

142. A hospital waiting area has floor dimensions of 8 m × 12 m and a height of 3 m to a

plasterboard ceiling. A packaged air conditioning unit is housed in an adjacent room. There is

a common wall of 15 m2 and sound reduction index of 35 dB to the two rooms. The sound

pressure level in the plant room is expected to be 72 dB. The reverberation time of the waiting

room is 1.3 s. Calculate the sound pressure level that will be produced in the waiting room.

Answer. 33 dB.

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143. A meeting room has floor dimensions of 8 m × 6 m and a height of 2.7 m to a

suspended tile ceiling. The reverberation time of the room is 0.7 s. A fan coil heating and

cooling unit creates a sound pressure level of 43 dB in the ceiling space. The acoustic tile

ceiling has a sound reduction index of 8 dB. Calculate the sound pressure level in the meeting

room.

Answer.37 dB.

144. A hotel bedroom is 6 m long, 5 m wide and 2.8 m high and it has a reverberation time

of 0.4 s. The air conditioning plant room generates a sound pressure level of 56 dB in the

service space above the ceiling of the bedroom. The plasterboard ceiling has a sound

reduction index of 16 dB. Calculate the sound pressure level in the bedroom.

Answer. 39 dB.

Sound power and pressure

145. State what is meant by sound power and sound pressure level. State the units of

measurement for sound power, sound pressure, sound power level and sound pressure level.

146. Define the terms ‘sound power level’ and ‘sound pressure level’.

147. Explain the term sound power level, SWL.

1. Number of watts acoustic energy output from a source.

2. Number of watts acoustic energy input at a source.

3. Calculates power in watts of acoustic energy from a formula suitable for all sources.

4. Describes the peak variation and frequency of acoustic power output from a machine.

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5. Relative scale for acoustic power of a source.

148. The frequency range used for assessment of sound power level, SWL, from machines is:

1. 0 to 200 MHz.

2. 1 kHz to 2 MHz.

3. 125 Hz to 8 kHz.

4. 63 Hz to 20000 Hz.


149. By what mechanism do ears respond to sound power level, SWL?

1. Ears have no mechanism.

2. Sound power radiates to vibrate the eardrum.

3. Acoustic vibration energy vibrates the body, which transfers through the body muscle

and bone structure to vibrate eardrums.

4. Acoustic power raises air pressure on eardrums.

5. Acoustic output power pulsates and vibrates air, raising air pressure waves; eardrum

vibrates from air pressure waves.

150. What does acoustic power generate?

1. A field of sound pressure waves around the source.

2. Noise.

3. Reverberant sound field.

4. A field of sound power waves around the source.

5. Sound power level in a room adjacent to where the source is located.

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151. Sound pressure level within a plant room consists of:

1. Uncomfortable noise.

2. Noise produced by physical vibration.

3. Noise transmitted through the building structure.

4. Direct sound field.

5. Direct plus reverberant sound field.

152. Direct sound field:

1. Increases in intensity further from the source.

2. Remains at a constant noise at any distance from the source while the hearer remains in

the source plant room.

3. Decreases linearly with distance from source.

4. Falls with the inverse square of the distance from the sound source.

5. Doubles the value of the reverberant sound field.

153. Reverberant sound field is due to:

1. Directly radiated noise from a machine.

2. Average value of the sound pressure waves bouncing around within the room.

3. Sound received by a room from structure transmission.

4. Background noise before plant is switched on.

5. Summation of all sound sources within a room.

154. Sound pressure level, SPL dB, within a room is:



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3. Reflected sound.

4. Greatest noise source.

5. Summation of direct and reverberant sound fields.

Sound power level

155. How much acoustic power is experienced within buildings?

1. 10% of electric motor power becomes acoustic energy.

2. Around 10 W/m2 floor area.

3. Above 1 kW.

4. Always below 500 W.

5. Less than 1 W.

156. Frequency range used for assessment of sound power level, SWL, from machines is:

1. 0 to 200 MHz.

2. 1 kHz to 2 MHz.

3. 125 Hz to 8 kHz.

4. 63 Hz to 20000 Hz.


157. By what mechanism do ears respond to sound power level, SWL?

1. Ears have no mechanism.

2. Sound power radiates to vibrate the eardrum.

3. Acoustic vibration energy vibrates the body, which transfers through the body muscle

and bone structure, to vibrate eardrums.

4. Acoustic power raises air pressure on eardrums.

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5. Acoustic output power pulsates and vibrates air, raising air pressure waves; eardrum

vibrates from air pressure waves.

Structure borne noise

158. How can the structure of a building transmit noise?

1. Concrete framed structures cannot, as noise is dampened.

2. Steel and concrete structures absorb all acoustic energy.

3. Structures always absorb acoustic energy and dissipate it as heat.


5. Physical movement.

159. Which is correct?

1. Concrete structures cannot pass sound, as it is dampened.

2. Steel and concrete structures dissipate all acoustic energy.

3. Structures always absorb acoustic energy.

4. Molecular vibration transmits acoustic energy.

5. Physical movement of structure eliminates noise.

160. How does noise enter a structure?

1. It cannot.

2. Only through cracks and openings.

3. Air pressure waves vibrate structure.

4. Physical vibration from rotary or reciprocating plant in contact with steel or concrete

structure.

5. Through windows.

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161. Sound transmission occurs:

1. From high SWL to low SPL.

2. Through dense concrete.

3. In the direction of airflow.

4. From a location of higher sound pressure level to a location of lower sound pressure

level.

5. From a location of higher sound power level to a location of lower sound power level.

162. Which is not a way to improve the sound insulation effectiveness of a single glazed

window?

1. Close it.

2. Seal all air gaps.

3. Leave window cracked open.

4. Seal gaps and double glaze.

5. Replace with thicker glass.

163. Sound insulation is:

1. Reticulation.

2. Attenuation.

3. Easy and low cost for sound frequencies below 1 kHz.

4. The same for all frequencies by all materials.

5. Temperature dependant.

164. Which is not true about building materials?

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1. Resonate at low frequencies, as low as 100 Hz.

2. Resonate at high frequencies, above 5 kHz.

3. All materials vibrate.

4. All have a natural frequency of vibration.

5. All attenuate sound.

Terminology

165. Explain the meaning of SWL:

1. Selective wind loading.

2. Sound wind level.

3. Sound watts level, meaning power.

4. Sound pressure level, meaning energy.

5. Sound watts loudness, meaning loudness power.

166. What does resonance mean?

1. Sound produced by a vibrating material.

2. Synchronous with 50 Hz alternating current frequency, such as a 3000 RPM motor.

3. Acoustic energy causing vibration.

4. Forcing frequency exceeds natural frequency of vibration of a material or plant item.

5. Forcing frequency equals natural frequency of vibration of a material or plant item.


1. Undamped vibration.

2. Strike a tuning fork and it vibrates at its natural frequency, perhaps sounding a musical

note.

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3. Bounce a coil spring and it vibrates at twice its natural frequency of vibration.

4. A frequency that cannot be mechanically produced.

5. A material or item can only vibrate at this frequency.


1. Damped vibration.

2. Strike a guitar string and it vibrates at up to four times its natural frequency depending

on volume of sound box.

3. Bounce a coil spring and it vibrates at its natural frequency of vibration.

4. A frequency mechanically forced upon an item, such as by a motor.

5. A material never vibrates at this frequency.

What sound does



2. Wind forces.




170. List the ways in which mechanical and electrical services plant, equipment and systems

generate sound.

171. Explain, with the aid of sketches and examples, how sound is transferred, or can be,

through a normally serviced multi-storey occupied building.

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172. Discuss the statement: ‘Turbulent flows in building services systems create a noise

nuisance.’

173. State how the building structure transfers sound.

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12 Air conditioning system cost

Project

1. A toilet extract system of air ductwork is part of a new construction project and is to have

the following components: 12 m of 400 mm × 400 mm air ductwork, one stopped end, six 90o

curved bends, one 45o bend, two branches, two transforms downwards from the duct size, one

fire damper 400 mm × 400 mm, two access doors 235 mm × 90 mm, two test holes and seal,

one 600 mm × 600 mm extract grille and damper, two axial flow fans, 0.47 m3

s each, two sets

of anti-vibration mountings for 25 kg fans, two push button starters for 0.5 kW fans, two

contactor relays for fan interlocking, six 13 amp electrical socket outlets with PVC cable in

conduit, commercial. Make your own decisions about what else is to be included in the

contractor’s selling price and calculate your tender figure.

2. An air handling unit supplies heated air to a manufacturing area of a single-storey building.

The extract air has become contaminated and is discharged to the atmosphere. The factory is

in the north of England where the regional price variation is +18%. The ductwork installation

will require the use of scaffolding. Use the following information to calculate the contractor’s

tender price to the main contractor.

Supply ductwork: Air intake weatherproof grille 2 m × 2 m and transition to the air handling

plant; one air handling unit 1 m × 1 m in cross section with air heater, filter and centrifugal

fan which passes 3 m3

s; one motorised damper of 1 m × 1 m; one transition from air handling

unit to a 800 mm × 600 mm duct; 50 m of 800 mm × 600 mm duct; five 800 mm × 600 mm

90o curved bends; six branch ducts for grilles; six supply grilles with damper 600 mm × 300

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mm; one 800 mm × 600 mm blank duct end; four access doors 235 mm × 140 mm; three test

holes and seals.

Extract ductwork: air discharge weatherproof grille 2 m × 2 m; one transition to the

centrifugal extract fan which carries 3 m3

s; one set of anti-vibration mountings for a 115 kg

fan; one transition from the extract fan to the ductwork; one motorised damper 800 mm × 600

mm; 20 m of 800 mm × 600 mm duct; two 800 mm × 600 mm 90o square bends with turning

vanes; one transition to a 1 m × 1 m grille; one extract grille and damper 1 m × 1 m; one 800

mm × 600 mm blank duct end; two access doors 235 mm × 140 mm; one test hole and seal.

Control equipment: three air temperature detectors; 1 Pa XY36 control unit, list price £300

and 3 hours labour; two 2 kW fan push button starters; one contactor relay; two damper drive

motors; one 32 mm three-port hot water diverting valve.

Electrical supply: one four-way triple pole and neutral 415 volt distribution board; 120 m of 4

mm2 415 volt cable in conduit; six 240 volt 13 ampere socket outlets; PVC cable in conduit

for a commercial application.

Hot water pipework: 220 m of 40 mm black medium steel low pressure hot water heating

flow and return pipework, brackets and fittings; 220 m of 40 mm pipe thermal insulation; four

40 mm gate valves; one 40 mm commissioning double regulating valve; two air vents; two

water pipe test points.

Concluding items: regional variation 18%; hire of scaffolding prime cost sum £2500;

additional overhead 5%; safety risk item £750 for use of scaffolding; commissioning cost

£275; decreased profit by 3% due to competition; fluctuation during contract 5%; there is only

the mechanical and electrical contractor on this existing site.

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3. An air conditioning system is to be installed in a new information technology room for 200

personal computer work stations in a university located in Scotland, regional price variation

15%. There is no space for air ductwork, so packaged cooling units are to be installed within

the room. Refrigeration condensing units will be located on the flat roof of the room.

The room cooling load for each computer work station is calculated to be 200 watts from

the computer, 110 watts from the user, 25 watts from the lighting, 100 watts from solar heat

gains and 20 watts from the outdoor air ventilation. There are to be two refrigeration

condensing units on the roof in order to provide 100% standby capacity. Each condensing unit

is to have a 5.5 kW push button starter. A contactor relay is to be installed to avoid the

possibility of simultaneous operation of the two condensing units.

Each room cooling unit will have 12 m of 20 mm diameter refrigeration pipework from the

condensing units. Assume that this will be in black medium weight steel tube and fittings for

the purpose of this exercise only. Both pipes will be insulated. There are no control items or

valves in the pipelines as all the controls are part of the condensing unit and room unit

packages.

Each room cooling unit has a 13 ampere 240 volt socket outlet with PVC insulated cable in

conduit for a commercial application. Each condensing unit has 20 m of 6 mm2 415 volt three

phase cable in conduit. A four-way triple pole and neutral 415 volt distribution board is

installed for the refrigeration system.

An extra cost item of £2500 is to be allowed for repairs to the structure and decorations

which will be necessary as the result of the installation work. No additional overhead costs are

expected. There are no additional safety costs. Commissioning the installed system will take 2

days work.

A highly competitive price is to be tendered and the contractor will reduce the allowance

for profit by 8%. The contract price will be fixed for the duration of the agreed period and

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there is no main contractor or discount. Calculate the cooling load in kW and number and

capacity of the split package room cooling units which are to be used. Note that there are

several possible solutions and these will be reflected in the project price. Evaluate a

competitive project sell price.

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13 Question bank

Acoustics



2. Wind forces.











1. Porous sound absorbing materials.

2. Thicker concrete walls and floors.

3. Bolt refrigeration compressor to concrete slab.

4. Line plant room with lead.

5. Sit further away from it.

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4. Which item of plant does not normally create noise?

1. Fans and pumps

2. Refrigeration compressors.

3. Fired water heaters.

4. Air compressors.

5. Piped systems.

5. Which frequency range is audible?

1. 2 kHz to 200 kHz.

2. Infinite range.


4. 0 Hz to 10000 Hz.

5. 20 Hz to 20 kHz.

6. A noisy machine on a plant room base:

1. Radiates direct sound in straight lines only.

2. Fills the plant room with noise.

3. Sounds equally noisy from all directions.

4. Produces a spherical field of sound waves.

5. Produces a hemispherical sound field.

7. A noisy machine on a plant room concrete floor:

1. Has no sound directivity.

2. May direct sound more strongly in a particular direction.

3. Sends a direct sound field through the floor.

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4. Only creates a reverberant sound field.

5. Gains a benefit from sound energy absorbed by the floor.


1. Noise resonance.

2. Normal rating.

3. No resonance.

4. Noise ratification.

5. Noise rating.








1. Noise rating curves specify equal sound power level for all frequencies.

2. Noise rating curves specify equal sound pressure level for any frequency.

3. Noise rating curves specify equal loudness for a range of frequencies.

4. Noise rating are subjectively assessed.

5. Machines are given a noise rating value.

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1. Cannot be reduced, only contained within the plant room.









structure.

4. Reflected sound.


13. Which is correct for sound reverberation time?

1. Time between echoes.

2. How long a sound level continues.

3. Time lag between directly received sound and reverberated sound.

4. Time for a sound to decrease to zero within a room after the source is switched off.

5. Time taken for a sound to decrease by 60 dB.


1. It has no reverberant sound field.

2. Its walls, floors and ceiling are perfect sound absorbers.

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3. It allows a spherical sound field from a centrally placed source.

4. It is used for measuring reverberation time from a test item.

5. It is a laboratory to measure sound power level of an item.



2. Wind forces.




16. Sound transmission occurs:

1. From high SWL to low SPL.

2. Through dense concrete.

3. In the direction of airflow.

4. From a location of higher sound pressure level to a location of lower sound pressure

level.

5. From a location of higher sound power level to a location of lower sound power level.

17. Sound pressure level, SPL dB, within a room is:



3. Reflected sound.

4. Greatest noise source.

5. Summation of direct and reverberant sound fields.

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Acronyms


1. ASHRAE means Australian Society for Heating, Refrigerating and Air Engineering.

2. AIRAH means American Institute for Refrigeration and Air Heating.

3. CIBSE stands for The Chartered Institution of Building Services Engineers.

4. BSRIA stands for British Services Refrigeration Institute for Air Conditioning.

5. CIC is the Council for Industry and Construction.

19. AR, BER, SER, DEC and iSBEM all relate to which?

1. Electrical engineering services and systems.

2. They are meaningless acronyms.

3. Types of zero carbon buildings.

4. Emission rating.

5. Types of energy audit.

20. What does BREEAM stand for?

1. Building Rehabilitation Electrical Energy Alternative Methodology.

2. Building Research Establishment Energy Audit Methodology.

3. Building Recycling Energy Effectiveness Association Member.

4. Brick Recycling Energy and Environment Assessment Method.

5. Building Research Establishment Environmental Assessment Method.


1. ASHRAE means American Society of Heating, Refrigeration and Air Conditioning

Engineers.

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2. AIRAH means Australian Institute for Refrigeration and Heating.

3. CIBSE stands for Council In British Scientific Engineering.

4. BSRIA stands for Building Services Refrigeration Institution for Air Conditioning.

5. CIC is the Construction Industry Confederation.


1. ASHRAE means African Society of Heating, Refrigeration and Air Equipment.

2. AIRAH means Australian Institute of Refrigeration Air Conditioning and Heating.

3. CIBSE stands for Chartered Institute for British Scientific Engineering.

4. BSRIA stands for Building Services Research Institution for Air Conditioning.

5. CIC is the Construction Information Committee.


1. ASHRAE means Armenian Society of Heating, Refrigeration and Air Conditioning

Engineering.

2. AIRAH means Austrian Institute for Refrigeration Air Heating.

3. CIBSE stands for Confederation of British Scientific Engineering.

4. BSRIA stands for Building Services Research and Information Association.

5. CIC is the Construction Industry Conference.


1. CIC is the Construction Industry Council.

2. EC means Engineers Confederation.

3. ODPM stands for Overall Design Primary Mandate.

4. RAEng is the Royal Army Engineering.

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5. REHVA stands for Refrigeration, Engineering, Heating, Ventilating Association.



2. EC means Engineering Council.

3. ODPM stands for Operational Design Permit Management process.

4. RAEng is the Royal Association of Engineers.

5. REHVA stands for Renewable Energy Heating and Ventilating Association.


1. CIC is the Construction International Confederation.

2. EC means European Confederation.

3. ODPM stands for Office of the Deputy Prime Minister.

4. RAEng is the Royal Aeronautical Engineers.

5. REHVA stands for Recherché Europe Harlanda Ventrique Appliqué.

27. Which of these are correct?

1. CIC is the Confederation International for Construction.

2. EC means European Construction.

3. ODPM stands for Order Directive from the Prime Minister.

4. RAEng is the Royal Academy of Engineering.

5. REHVA stands for Federation of European Heating and Air Conditioning Associations.

28. What does LEED stand for?

1. Low Energy Environmental Design.

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2. Leadership in Energy and Environmental Design.

3. Low Electrical Energy Demand.

4. Leading Electrical Energy Demonstration.

5. Leader in Energy Environment and Design.

29. What does the acronym BREEAM stand for?

1. Building Recyclers Associate Member.

2. A fish.

3. Registered trade mark of the Building Research Establishment.

4. Organisation for the study of the flow of building-sourced debris in waterways.

5. A system demonstrating inefficient building design strategies.

30. What does the acronym BREEAM mean?

1. Assessment of the environmental performance of a building.

2. Only used to analyse house designs.

3. Only applicable to new commercial building developments.

4. Energy assessment system for office buildings.

5. Completed building design solutions can be assessed for energy effectiveness.

31. What is correct regarding BREEAM?

1. Should be commenced at earliest preliminary design stage of a building.

2. Too late to use it once building is designed.

3. Cannot be applied to residences.

4. Must not be used to analyse existing buildings.

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5. Cannot include health of indoor and outdoor environments for a building.

32. What is correct regarding BREEAM?

1. Exposes inadequate design proposals.

2. Cannot produce an overall score for the building.

3. Ratings awarded as fail, not recommended, minimum pass and recommended.

4. Certificate awarded can be used by building owner for promotional purposes.

5. A poorly rated building should remain confidential to the building owner.

33. Which is not true about BREEAM?

1. Can be applied to industrial buildings.

2. Can be awarded to offices, homes, retail premises and schools.

3. Conducted by accredited raters.

4. Ratings awarded as pass, good, very good and excellent.

5. Too new and not popular with building owners as a poor rating reduces rental potential.

34. What does the acronym LEED stand for?

1. Lagging Energy Efficiency Download.

2. Leicestershire Energy and Environmental Design method.

3. Leeds, UK, energy analysis system for commercial building auditing.

4. Nothing to do with green building rating schemes.

5. Scheme devised by the Green Building Council, USA.

35. Which is not correct about LEED?

1. A rating scheme only applying to new or green field building developments.

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2. Leadership in Energy and Environmental Design.

3. Provides ratings for houses, commercial, health, educational new and existing buildings.

4. A framework for assessing building performance.

5. Defines green buildings.

36. What does ABGR stand for?

1. No meaning.

2. All Buildings Green Rationale.

3. All Building Greenhouse Rating.

4. Austrian Building Green Rating.

5. Australian Building Greenhouse Rating.

37. Which is correct regarding ABGR?

1. Uses a standard multiplier for floor area and building type.

2. Applies to every type of building.

3. Based upon all energy consumption in a building for a year.

4. Absolute Building Green Rating.

5. All British General Rating system for all functions of a building.

38. Which is the correct meaning for ABGR?

1. All British Green Rezoning.

2. All British Greenhouse Rating.

3. Actual British Greenhouse Rating.

4. Australian Building Greenhouse Rating.

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5. Australian Business Greening Rebate.








1. ASHRAE means American Society of Heating, Refrigeration and Air Conditioning

Engineers.

2. AIRAH means African Institute for Refrigeration and Heating.


4. BSRIA stands for Building Services Refrigeration Institution for Air Conditioning.

5. CIC is the Construction Industry Confederation.


1. ASHRAE means African Society of Heating, Refrigeration and Air Equipment.

2. AIRAH means Australian Institute of Refrigeration Air Conditioning and Heating.

3. CIBSE stands for CooperativeInstitute for British Science and Environmen t.

4. BSRIA stands for Building Services Research Institution for Automatic Control.

5. CIC is the Construction Information Committee.


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1. ASHRAE means Armenian Society of Heating, Refrigeration and Air Conditioning

Engineering.

2. AIRAH means Austrian Institute for Reclaimable Air Heating.


4. BSRIA stands for Building Services Research and Information Association.

5. CIC is the Construction Industry Conference.



2. EC means Environment Confederation.

3. ODPM stands for Overall Design Pre Maintenance.

4. RAEng is the Royal Authority Engineering.

5. REHVA stands for Reusable, Engineering, Heating, Ventilating Association.


1. CIC is the Concrete Industry Confederation.

2. EC means Engineering Council.

3. ODPM stands for Operational Design Permit Management process.

4. RAEng is the Retired Association of Engineers.

5. REHVA stands for Renewable Environment Heating and Ventilating Association.


1. CIC is the Construction Internetl Communications.

2. EC means Environmental Confederation.

3. ODPM stands for Office of the Deputy Prime Minister.

4. RAEng is the Racing Aerodynamic Engineers.

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5. REHVA stands for Recherché Europe Harlanda Ventrique Appliqué.

46. Which of these are correct?

1. CIC is the Confederation International for Concrete.

2. EC means Environmental Construction.

3. ODPM stands for Overall Direction from the Primary Minister.

4. RAEng is the Royal Academy of Engineering.

5. REHVA stands for Federation of European of Heating and Air Conditioning

Associations.

Air conditioning

47. Do air conditioning and lift systems lead to obesity?

1. Yes, absolutely.

2. Obesity is due to overeating only.

3. Obesity is due to working at computers too long each day.

4. Metabolism slows and we eat more in air conditioned environments.

5. Modern facilities tend to reduce our physical activity and lead us to eat less natural

food.

48. Which is not a current means of operating a humidifier?

1. Electrode or immersion heater steam boiler.

2. High pressure pumped water fog spray.

3. Spinning disk water atomiser.

4. Compressed air water atomiser spray.

5. Water tray in an AHU.

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49. Does air conditioning lead to obesity? Which of these may not be a valid argument?

1. Keeping home, vehicle and workplace at one temperature all year round promotes body

fat.

2. Cool air temperature encourages fat burning.

3. Thermal neutrality can only maintain the obesity status quo.

4. Warm air temperature decreases natural appetite.

5. Natural body temperature regulation from variable air temperature is a good thing.


1. Recent research suggests thermal neutrality removes the need for natural body

temperature regulation activity to burn fat.

2. Obesity is due to lack of exercise.

3. Obesity is due to inadequate sleep.

4. Obesity is due to endocrine disruptive substances found in food.

5. Cannot possibly be the fault of air conditioning.


1. Obesity is due to overeating.


3. Humans need outdoor environment exposure to regulate body temperature.


5. People eat less when the air around us is very warm.


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1. Being too comfortable indoors makes us physically inactive.

2. We burn energy to combat the effects of the hot and cold environment.

3. In air conditioning, we become inactive.

4. In air conditioning, we eat more.

5. Stable thermal environment allows the body to rest and suppresses appetite.

53. Which is a valid justification for air conditioning?

1. Buildings packed to capacity with people, computer workstations and artificial lighting

usually need air conditioning in the UK.

2. The future habitability of planet Earth is assured whatever we may do to its natural

resources.

3. The pattern of energy use for the next 100 years of a building’s use has nothing to do

with its designers.

4. Building designers must ignore those few days in the year when hot humid weather

makes indoor conditions uncomfortable without mechanical cooling systems.

5. Correct design of glazing in commercial buildings for the UK always eliminates the

need for air conditioning.


1. Stands for valve authority value.

2. Only used in hotels and conference centres.

3. Reducing room demand for cooling opens the VAV damper.

4. Rise in zone air temperature causes the VAV damper to throttle the cool supply air flow

further.

5. Single duct all-air system with a throttling damper at each room supply air outlet.

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1. Does not require distribution air ducts.

2. Self-contained air conditioning unit.

3. Only requires an outside air duct and electrical power connection.

4. A cooling only terminal unit.

5. Usually have air ducts, chilled water, hot water flow and return plus condensate drain to

sewer pipework.

56. Which of these applies to packaged room air conditioning units?

1. Always connected to a ducted air system.

2. Always connected to a central chilled water plant system.

3. Each unit has a refrigeration compressor.

4. Always very quiet operation.

5. Power demand not exceeding 250 W

57. Wet bulb thermometer:

1. No such thing.

2. Dry bulb mercury in glass thermometer immersed in a water tank.

3. Does not work in humid air

4. Used inside a 38 mm diameter black copper globe.

5. Mercury in glass thermometer having a wetted cotton sock covering the sensing bulb.

58. How is sick building syndrome defined?

1. Many people consider working in the building makes them sick.

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2. Publicised condemnation of the building.

3. That combination of health malfunctions that noticeably affect more than 5% of the

building’s population.

4. Accumulation of health malfunctions noticeably affecting 25% of the buildings users.

5. User formalised surveys finding overall dislike for an inadequately comfortable

environment.

59. Which is not correct about air ductwork?

1. Spiral wound flexible fabric ducts make final connections to terminal units and diffuser

boxes.

2. Air ducts have taped joints for air tightness.

3. Air duct leakage is unimportant.

4. Galvanised sheet steel ductwork has riveted or flanged joints.

5. Air ducts can be cleaned internally.

60. Difference between dry and wet bulb thermometer readings:

1. Called the wet bulb depression.

2. Measures room atmosphere depression.

3. Used to find the vapour pressure of the room air.

4. Wet bulb temperature is always higher than the dry bulb temperature due to evaporative

heat transfer.

5. Dry bulb temperature is always higher than the wet bulb temperature due to evaporative

heat transfer.

61. Ventilation rates:

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1. Are never measured.

2. Designed rates are never achieved due to duct losses.

3. Vary from 4.0 to 25.0 air changes per hour for air conditioned office spaces.

4. Cause drafts.

5. Mean that supply air grilles in office ceilings must direct air away from sedentary

personnel.


1. Duplicated supply and return air ducts.

2. A reduced cost design.

3. Simultaneous heating and cooling to adjacent rooms.

4. Not used in commercial office buildings.

5. Appropriate for low energy new buildings.

63. What is the meaning of chilled beam?

1. Structural steel beam that is kept cool by the air conditioning system.

2. Structural steel beams supporting the weight of the air conditioning system water chiller

compressors.

3. Air conditioning surface operating at below the occupied room air dew point

temperature.

4. A chilled water surface providing only radiant cooling.

5. Finned pipes or flat panels at high level in offices providing a convective cooling

surface.

64. Which is correct about commissioning air duct systems?

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1. Air duct systems do not need to be inspected during commissioning.

2. All air ducts must be internally cleaned prior to commissioning.

3. All air ducts must be internally inspected with remote controlled lamps and cameras

before use.

4. Rough internal projections, rivets and metal cuttings are removed by the commissioning

technician.

5. Air ducts systems are sealed in sections and pressure tested for an airtightness standard

compliance.







66. And finally, what have I learnt from this study?

1. Nothing, it is all a fog to me!

2. Mechanical and electrical services within a building are not very important to the

overall concept of the design and construction.

3. I can design or construct buildings; someone else must worry about the fiddly bits.

4. The building will work without the mechanical and electrical services anyway.

5. I now appreciate the importance and main features of air conditioning!

Air quality

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67. We sense odours by:






68. Air quality may be deemed satisfactory when:






69. Which of these may not be a cause for sick building syndrome?

1. Job related stress and overwork.

2. Canteen food.

3. Excessive working hours.

4. Lack of exercise during the working day.

5. Perception of lack of personal support at work.

70. Which of these may not be a cause for sick building syndrome?

1. Airborne fungi.

2. Noise.

3. Air filtration standard too high quality for the application.

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4. Workstation ergonomics inadequate.

5. Boring or unsafe work.


1. Tobacco smoke.

2. Volatile organic compounds, VOC, from cleaning fluids.

3. Nitrogen.

4. Carbon monoxide.

5. Nitrogen dioxide.


1. Pipe tobacco smoke.

2. Volatile organic compounds, VOC, from new furnishings and floor coverings.


4. Nitrogen trioxide.

5. Carbon dioxide.

73. Where are oxides of nitrogen created?

1. Nitrogen is inert, it cannot oxidise.

2. Hydrocarbon combustion.

3. Electrolysis of air from electric sparks or lightning.

4. Chemical reaction within lungs.

5. Leakage of nitrogen from high pressure liquid storage.


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74. Which of these are not a means for data transmission?

1. Cable conduit.

2. RS484.

3. 240 volt cables.

4. RS124.

5. Ethernet.

75. Which of these is not a common standard for data transmission?

1. Wi-Fi.

2. RS484.

3. RS232.

4. RS300.

5. Comm-bus on a motherboard.

76. Which one of these would you not like to be a feature of an intelligent building?

1. Window external louvres control solar gain from solar radiation sensor on each facade.

2. Car park ventilation fan speed varied in speed to respond to carbon monoxide level

within underground car park.

3. Lift sensing controls that minimise travel time for every passenger to each destination

by means of the user’s electronic tag worn at all times.

4. Each workstation has air conditioning, lighting and glare control that adjusts to each

specific user.

5. Manual key entry to building, window shade adjustment, light switches and no personal

control over air conditioning.

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CO2 emissions

77. Which is correct for the level of CO2 emissions from the UK?

1. 500 mega tonnes per year.

2. 500 tonnes per year.

3. 500 giga tonnes per year.

4. There aren’t any.

5. 500 million kilograms per year.

Density

78. Which is correct about the density of humid air?

1. Decreases with increasing pressure.

2. Increases with increasing air temperature.

3. Varies with air temperature and pressure.

4. Not affected by humidity.

5. Increases as air velocity increases.

79. Which is correct about the density of water?

1. Always 103 kg/m3.

2. 1013.25 m3/kg.

3. 101325 kg/m3.

4. 1.205 MJ/m3 K.

5. 1000 kg/m3 at 4oC.


1. Cannot be measured.

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2. Cannot be measured accurately.

3. Always relative to the specific gravity number.

4. 1000 times that of air.

5. Specific gravity is 1.0.


1. 1.205 × 105 kg/m3.

2. 1 tonne/m3 at 4oC.

3. 1.012 × 103 kJ/m3.

4. 1.27 kJ/kg K.

5. 100 g/cm3.


1. 11 g/cm3.

2. 1.2 × 103 kg/m3.



5. 1 kg per litre.

Electrical

83. What does inverter mean?

1. Alternating current phases are reversed.

2. It is an electronic soft starter for a three phase motor.

3. Incoming 50 Hz alternating current is digitally reformed into an output frequency to a

motor in the range from 0 to 50 Hz.

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5. Alternating current is electronically converted into direct current to drive a motor.


1. Alternating current phases are returned.

2. It is an electronic soft starter for a single phase motor.

3. Incoming 50 Hz alternating current is digitally reformed into an output higherfrequency.



5. Alternating current is magnetically converted into direct current to drive a lift motor.

85. Why use a variable frequency inverter?

1. Motor runs quieter.

2. Less cost than a refrigeration capacity control system.

3. Saves energy as power consumption depends on motor speed.

4. Does not save anything and is a marketing gimmick.

5. Easier to control from a BMS.

86. Photovoltaic cells are used for which?

1. Controlling artificial lighting systems.

2. Intruder detection.

3. Generating electricity.

4. Digital photography remote sensing.

5. Digital security camera data collector.

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87. What do we know about the energy effectiveness of wind turbine electricity generators?

1. They are 100% efficient.

2. Propeller blades are the least efficient design of turbine blade.

3. Power generation remains constant all day and night.

4. Wind velocity always turns the turbine.

5. Control system switches turbine generation on and off according to demand.

88. What do we know about the energy effectiveness of wind turbine electricity generators?

1. They are very efficient at capturing free energy from the wind.

2. Propeller blades fly aeroplanes so must be very efficient turbines.

3. Annual average generation is around 35% of maximum potential.

4. Once installed they last forever.

5. Wind turbines create no noticeable downside on the environment.

89. How much greenhouse gas, carbon dioxide, comes from electricity?

1. None, it is the combustion of primary fuel to generate electricity that produces

atmospheric CO2.

2. 1.0 tonne CO2 per MWh.

3. Around 0.4 kg CO2/kWh.

4. Around 4 kg CO2/kWh.

5. Around 40 kg CO2/kWh.

90. What does a CHP plant do?

1. Generates electricity for the national grid.

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2. Provides emergency power when public supply fails.

3. Burns natural gas to generate hot water heating.

4. Gas turbine engine drives an alternator in a public supply power station.

5. On-site gas turbine or reciprocating engine drives an alternator while engine cooling

water heats the building.

91. What are photovoltaic cells used for on buildings?

1. Never used as they are an uneconomic embellishment.

2. What is a photovoltaic cell?

3. Alternative to roofing material.

4. Charging 12 volt emergency power supply batteries, UPS.

5. On-site electricity generation with alternating current rectifiers, battery storage and

often used to meet some of the artificial lighting continuous demand.

92. What is the meaning of inverter drive?

1. An electric motor installed in an inverted position.

2. Three phase electric motor.

3. Three phase motor running in single phase.

4. Digitally driven motor.

5. Motor driven at variable alternating current frequencies.

Fabric energy storage

93. Which is correct about fabric energy storage?

1. Inconsequential in sizing air conditioning plant.

2. Thermal insulation greatly reduces heat flow into walls and roofs.

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3. Fast response by the building to temperature controllers is preferred.

4. Warmth and coolness stored in concrete is useful.

5. Labyrinths do not work as they are dust and infestation sources of contamination in the

outside air stream.

94. What use are hollow concrete floors?

1. None.

2. They do not add or extract heat from air supplied through them.

3. Only used as pipe and cable ducts.

4. Sound hollow to foot traffic and are an annoyance to the lower floor occupants.

5. Tempers supply air as part of a low energy air conditioning system.

Fans


1. Gas engine prime mover.

2. Six-pole phase electric motor.




General knowledge

96. Which is correct about CCS?

1. Centralised carbon separation.

2. Too expensive to contemplate.

3. Potential to return most of carbon from flue gas back to the earth.

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4. Good idea from the oil and gas industry.

5. A political nightmare.

97. Economic thickness of thermal insulation is which of these?

1. Found by calculation of minimum total cost.

2. When graph of capital cost of additional thermal insulation become horizontal.

3. When a graph of energy savings value reaches a peak.

4. Always occurs when payback from energy cost savings reaches two and a half years.

5. Thickest amount the building designer can accommodate.






5. Combustible gaseous fuel.

99. A daytime use low energy primary school in northern England has walls, roof and floor

thermal transmittances below 0.2 W/m2 K. Windows are double glazed with a U value of 2

W/m2 K and natural ventilation is automatically controlled. A biomass condensing water

heater burning woodchip fuel provides low temperature under floor and convector heater

central heating. The water heater fuel hopper is filled daily. Locally sourced forest regrowth

creates a carbon neutral building load. Spot the most significant of the problems.

1. Perfect scenario as heating creates no additional greenhouse gases.

2. Incomplete combustion of woodchip is an environmental hazard.

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3. Daily maintenance duty makes plant operation inconvenient and costly.

4. Not a project widely applicable in the UK and produces odorous smoke that pollutes

nearby housing and commercial property; retrograde technology.

5. Basic design error of inability to control heat output from a continuously burning solid

fuel furnace in meeting a highly intermittent heat demand, leading to space overheating.

100. A newly constructed daytime use low energy primary school in northern England was

anticipated to consume around 20 kWh/m2 floor area of electricity in accordance with design

standards. The first two years of operation showed electrical energy consumption of 80

kWh/m2. Spot the most significant probable cause of this non-compliance.

1. More electrical equipment installed than intended.

2. Less efficient electrical equipment installed than design standards.

3. Laptop computers, lights and data projectors remain switched on continuously.

4. The new building proves to be so warm and useful, it becomes fully used for

community events after school hours, and evenings, weekends and school holidays.

5. Design data grossly under-estimates real usage.

101. A newly constructed 15 kW propeller blade wind turbine cost £50000. It is installed on

a site where wind is expected to provide an average usage efficiency of 35% over the whole

year. Potential energy generation value is £3000 per year. How many years will the wind

turbine take to recover its capital cost?

1. 15

2. 10

3. 16

4. 17

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5. 35

102. Which is true about household gas consumption?

1. Sold in kWh units.

2. Sold in MJ units.

3. Varies with type of use and number in household.

4. Household use can be reliably predicted.

5. Predictable from local annual degree days.

103. Which is correct about CCTV?

1. Computer closed television.

2. Computer connected total ventilation.

3. Closed circuit television.

4. Continuous circuit telephone version.

5. Circuit computer television.

104. CFD stands for?

1. Comfort for disabled people.

2. Computational fluid dynamics.

3. Computer fluid dynamics.

4. Comfort frequency diagram.

5. Computer flow diagnostics.

105. Which applies to atria?

1. Allows tall plants and trees to grow indoors.

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2. Purely decorative feature.

3. Creates feeling of spaciousness in an otherwise cramped building site.

4. An entirely modern, 21st century, concept.

5. Creates draughty high ceilings.

106. Which is not correct about atria?

1. Provides visual stimulus.

2. Often requires air conditioning.

3. Saves the cost of lift shafts.

4. Allows noise and glare to annoy sedentary workers.

5. May function as the return air path to the AHU.

107. Which is the specific heat capacity of air?

1. Sensible heat content, kJ/kg.

2. Total heat content, kJ/kg.

3. 1.205 kJ/kg.

4. 1.012 kJ/kg K.

5. 4.186 kJ/kg K.


1. Ratio of absolute specific heat capacities.

2. Cannot be defined.

3. Varies with atmospheric pressure.

4. 1.012 kg K/W.

5. 1.012 kJ/kg K.

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109. Which is the specific heat capacity of water?

1. 1.013 kW/kg K.

2. 1.012 MJ/kg K.

3. 4.186 kg K/kW.

4. 4.186 kJ/kg K.

5. 4.2 kg K/kJ.

110. Which is correct about the specific heat capacity of water?

1. Varies with water pressure.

2. 4.19 kW s/kg K.

3. A ratio.

4. 1.102 kJ/kg K.

5. Used to calculate the flow rate of heating and cooling system water.








1. 4.186 kg/m3 at 21oC, 60% relative humidity.

2. 1.013 kg/m3 at 20oC, sea level.

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3. 0.802 m3/kg.

4. 1.205 kg/m3 at 20oC, 1013.25 mb.

5. 5.67 kg/m3.

113. What does the exponential, e, mean?

1. A logarithm.

2. A variable number.

3. Always 10x, ten to the power x.

4. 2.718

5. Has no meaning.


1. Something which is raised to a power.

2. 10x.

3. The sum of an infinite series.

4. Ratio of circumference to diameter of a circle.

5. 2.718.

115. Which is correct about window shading?

1. Exterior solar blinds and shades eliminate solar heat gain through glazing.

2. Sedentary workstations alongside large areas of glazing may be unusable without solar

shading.

3. Solar radiation through glazing is the sole source of summer heat gain into a building.

4. Heat absorbing coloured glass completely avoids the need for additional shading.

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5. Air conditioned buildings should have small windows.

116. Which is correct about energy use in buildings?

1. Designers cannot predict future energy use of a building.

2. Energy modelling predicts design energy use by a building.

3. Retrofitting low energy systems into existing buildings is easily done in later years.

4. Future retrofitting of energy-saving systems can easily reduce an existing building’s

consumption to 25% of its design energy use.

5. The best that future retrofitting can hope to achieve is a 25% reduction in a building’s

actual energy consumption.

117. Which applies to atria?

1. Good fortall trees to grow indoors.

2. Unjustifiabledecorative feature.

3. Creates feeling of spaciousness in a large building.

4. An ancientconcept.

5. Creates noisy cathedralceilings.

118. What does an air curtain do?

1. Provides a security screen at an international airport flight passenger entrance.

2. Provides a draught to overcome prevailing wind direction at a doorway.

3. Creates a downward or horizontal air stream across an open doorway.

4. Makes entering a building very draughty.

5. Wastes energy from fan power.

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119. Designing domestic hot water systems is which of these?

1. An exact science as all water flows are known to the designer.

2. Cold and hot water storage quantities to allow for all simultaneous demand possibilities.

3. Provision of estimated storage and delivery quantities for randomly distributed demand.

4. A strategy to overcome any usage.

5. Finding the lowest cost system that will avoid most complaints.

120. Which is correct about CCTV?

1. Computer circuit television.

2. Computer connected timed ventilation.

3. Closed circuit television.

4. Closed circuit telephone voice.

5. Control circuit total voiceover.

121. CFD stands for?

1. Computers for dyslexics’.

2. Computational fluid dynamics.

3. Calculated fluid dynamics.

4. Comfort frequency diagnosis.

5. Carbon dioxide future..

Government policies

122. What do you think of the HM Government Carbon Plan 2011?

1. Will shake up the EU.

2. Will cease further carbon dioxide pollution.

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3. Will not save the world.

4. Makes the UK smarter than the USA.

5. Brave.

123. Which is correct about International Energy Agency data?

1. Shows that all countries are reducing emissions.

2. Advertises good countries.

3. Rates countries according to their energy consumption.

4. Shows that global CO2 emissions are on target for compliance with the Kyoto Protocol

1997.

5. Demonstrates what is really happening with world emissions.

124. Which does the HM Government Carbon Plan 2011 do?

1. Has little effect on gas and petroleum consumption.

2. Diminishes energy use in buildings.

3. Prescribes how buildings are to be insulated and operated.

4. Is an alternative to the EU ETS.

5. Encourages reducing CO2 emissions.

125. Does taxing hydrocarbons reduce global CO2 emissions?

1. Of course it does, proven during recent 100 years of industrialisation.

2. Forces the design of modest energy using buildings.

3. Reduces personal transportation emissions.

4. Not done so yet.

5. Taxation is a punishment for emitters.

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l

126. What is the HM Government Carbon Plan 2011 for?

1. Political gain within the UK.

2. Compliance with the Kyoto Protocol 1997.

3. Promotes green building design.

4. So that the UK performs better at reducing emissions than other EU nations.

5. To build more nuclear power stations.

127. What is the HM Government Carbon Plan 2011 for?

1. Political gain within the EU.

2. To remove carbon pollution.

3. Become the lowest energy cost nation.

4. To be ahead of the USA.

5. Reduce emissions.

128. Will the HM Government Carbon Plan 2011 achieve anything?

1. Counteract growth of emissions from China.

2. Remove atmospheric carbon dioxide.

3. No.

4. Be ahead of the USA.

5. It already has.

Heat transfer



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4. Latent heat transfer is seen by condensation.

5. Sensible heat transfer only takes place through conduction and convection.


1. Sensible heat transfer always comprises all forms.

2. Latent heat transfer reduces air temperature.

3. Sensible heat transfer is only measured by a thermocouple and thermistor.


5. Sensible heat transfer only takes place through radiation.

131. Which correctly describes types of heat transfer?

1. Sensible heat transfer is the logical method.

2. Latent heat transfer occurs only in steam.

3. Radiation heat transfer is neither sensible nor latent.

4. Latent heat transfer is easily measured.

5. Sensible heat transfer takes place from an area of higher temperature to one of lower

temperature.

132. Which is not correct about thermal transmittance?

1. Calculated from summation of all thermal resistances through a structure.

2. Unique value for a building material.

3. Different values for walls, floors and roofs to comply with building regulation

standards.

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4. Reciprocal of the total thermal resistance of a building element.

133. Which is correct about the Stefan–Boltzmann constant?

1. Used to calculate convective heat transfer.

2. 4.186 kJ/kg K.

3. 1.012 kJ/kg K.

4. 5.67 × 10−8 W/m2 K4.

5. Combines convective and radiant heat transfer.


Low energy buildings

134. Which describes a zero carbon building?

1. Supplied from solar power systems.

2. Forested timber, no glass, naturally heated and ventilated.

3. Consumes a minimum amount of energy for all uses.

4. Net exporter of electricity.

5. Probably no such thing.

135. Which are the energy benchmarks used?

1. Best practice and normal for that building type.

2. Zero energy and worst example.

3. BREEAM zero score and LEED maximum allowed.

4. Asset Rating scale A to G.

5. A 1950 heated and naturally ventilated office and a fully air conditioned tower office.

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136. When designing the shape of a building:

1. Maximise exposure to solar warming.

2. Ignore location, make it impressive.

3. Minimise solar overheating.

4. Square in plan is always better for energy saving.

5. Minimise external surface area.


1. Building designers accurately calculate future energy use.

2. Architects do feedback studies of all their buildings.

3. New buildings always work perfectly as design predictions.

4. PROBE stands for probable recycling of built environment.

5. Only careful analytical review establishes how a new building achieves its objectives.

138. What does greenhouse rating of a building stand for?

1. The higher the greenhouse gas production due to the building, the higher the greenhouse

rating.

2. A 10 star building produces no greenhouse gases.

3. Assessed greenhouse gas emission standard of a building.

4. Any new building even if not painted green.

5. An emission standard applied to all types of buildings.

139. Which is correct about low energy buildings?

1. A low energy building is one that requires the minimum amount of primary resource

energy to build it.

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2. A low energy building may consume more energy to construct.

3. A low energy building consumes less energy during its 100+ years of use than an

equivalent building.

4. We have no idea what an equivalent building is for a specific site.

5. All buildings consume uncontrolled amounts of energy.

140. Which is correct about low energy building designs?

1. Are always modern and look impressive.

2. Are always found to be ideally comfortable by users.

3. Must have large windows and glazed walling.

4. Must have small windows and high levels of thermal insulation.

5. Should consume a minimum of primary energy when compared with similar types and

sizes of buildings.

141. What does sustainability mean for low energy buildings?

1. The mechanical and electrical services within this building all have a low maintenance

requirement.

2. All the water, sewerage, paper and plastic waste output from this building go to

recycling.

3. All the light bulbs and tubes from this building are recyclable.

4. Somebody has found a good argument why this design of building is less harmful to the

global environment than competitive designs.

5. This building has consumed, and will continue to consume, more of the Earth’s

physical resources than it can ever put back.

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142. Low energy buildings in a hot country such as Australia:

1. Cannot be achieved.

2. Must not have air conditioning.

3. Will always consume more primary energy than an equivalent building in northern

Europe.

4. Must have small windows.

5. Need perimeter shading with sun blinds and low transmission glazing.

143. What does Green Star stand for?

1. This building only uses renewable energy sources.

2. No such thing as a green star.

3. A low mould growth building.

4. Zero condensation risk.

5. Standard for environmental performance of the building.



rating.



4. Greenhouse rating stars awarded are inversely proportional to the tonnes of carbon

dioxide created by the building.



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1. No such thing as a modern sustainable building.

2. Everything used in the buildings service life comes from globally sustainable resources.

3. This building is an example of good modern design practice.

4. All waste output from this building is recycled.

5. The building has been constructed from organically grown materials.



energy to build it.


3. A low energy building consumes less energy during its 100+ years of use that an



5. All building consume uncontrolled amounts of energy.

147. Low energy buildings in hot countries such as UAE:

1. Easilyachieved.

2. Have low cost air conditioning.

3. Will use three to four times theprimary energy than an equivalent building in northern

Europe.

4. Need less maintenance than in cold climates.

5. Haveperimeter shading and low transmission glazing.

Lucky dip


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149. Which does the HM Government Carbon Plan 2011 do for air conditioning in

buildings?

1. Has little effect on primary energy consumption.

2. Diminishes energy use in some buildings.

3. Prescribes how buildings are to be air conditioned.

4. Is an alternative to the EU ETS.

5. Encourages reducing CO2 emissions.

150. Do air conditioning and lift systems lead to obesity?

1. Yes, absolutely.

2. Obesity is due to overeating only.



5. Modern facilities tend to reduce our physical activity and lead us to eat less natural

food.

151. Which of these is not a common standard for data transmission in a BMS?

1. Ethernet.

2. RS484.

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3. RS232.

4. RS124.

5. C-bus.


1. Building designers accurately calculate future energy use.

2. Architects do feedback studies of all their buildings.

3. New buildings always work perfectly as design predictions.

4. PROBE stands for probable recycling of built environment.

5. Only careful analytical review establishes how a new building achieves its objectives.



2. Everything used in the buildings service life comes from globally sustainable resources.



5. The building has been constructed from organically grown materials

154. Which describes a zero carbon building?

1. Supplied from solar power systems.

2. Forested timber, no glass, naturally heated and ventilated.

3. Consumes a minimum amount of energy for all uses.

4. Net exporter of electricity.

5. Probably no such thing.

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155. Which correctly describes air conditioning heat transfer?





5. A CHW cooling coil lowers air temperature and creates condensation.

156. How is air leakage by a building measured?

1. Anemometer readings at every opening to outdoors.

2. Fill with smoke and time taken to fully disperse.

3. Cannot be done at all.

4. Large fan sucks air out of whole building at −50 Pa and flow measured.

5. Large fan pressurises building at 50 Pa and flow measured.

157. AR, BER, SER, DEC and iSBEM all relate to which?

1. Electrical engineering services and systems.

2. They are meaningless acronyms.

3. Types of zero carbon buildings.

4. Emission rating of a building.

5. Types of energy audit.

158. When designing the shape of a building:

1. Maximise exposure to solar warming;

2. Ignore location, make it impressive;

3. Minimise solar overheating;

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4. Square in plan is always better for energy saving;

5. Minimise external surface area.

159. We sense odours within air conditioned buildings by:







1. Alternating current phases are reversed.

2. It is an electronic soft starter for a three phase motor.





5. Alternating current is electronically converted into direct current to drive a motor.







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163. Air conditioning may be deemed satisfactory when:








rating.



4. Any new building even if not painted green.


165. Which is correct about Kelvin?

1. Has no significance.

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2. Imperial system unit of heat.

3. Measured in kJ.

4. Temperature scale.

5. Absolute temperature.



energy to build it.


3. A low energy building consumes less energy during its 100+ years of use than an



5. All buildings consume uncontrolled amounts of energy.

167. Which might be a means of reducing refrigeration system energy usage?

1. Install smallest capacity compressors possible.

2. Carry out frequent maintenance checks and parts replacement.

3. Switch reciprocating compressors off for as long as possible and maintain wide

temperature differentials.

4. Use outdoor air cooled condensers.

5. Variable refrigerant volume scroll compressor with software controlled digital operation

programmable for all variations in year round duties.

168. Which is correct about low energy building designs?

1. Are always modern and look impressive.

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2. Are always found to be ideally comfortable by users.

3. Must have large windows and glazed walling.

4. Must have small windows and high levels of thermal insulation.

5. Should consume a minimum of primary energy when compared with similar types and

sizes of buildings.

169. What does sustainability mean for low energy air conditioned buildings?

1. The mechanical and electrical services within this building all have a low maintenance

requirement.

2. All the water, sewerage, paper and plastic waste output from this building go to

recycling.

3. All the light bulbs and tubes from this building are recyclable.

4. Somebody has found a good argument why this design of building is less harmful to the

global environment than competitive designs.

5. This building has consumed, and will continue to consume, more of the Earth’s physical

resources than it can ever put back.

170. How is the air pressure sealing, or leaking, ability of a building found?

1. Close all doors and windows. Close spill air and exhaust air dampers. Run supply and

return air fans. Measure internal static air pressure for one hour to see if it can be

maintained at a set value.

2. Close all doors, windows, air vents, exhaust air outlet ducts and spill air dampers. Run

supply and return air fans. Raise building air static internal pressure to 50 Pa above

outdoor atmosphere barometric pressure. Switch fans off. Measure rate of decay of

indoor air pressure. Use formula to calculate air leakage rate from building.

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3. Switch off all fans. Seal all mechanical ventilation openings into building with

polythene sheet. Fit false main entrance door having a pressurising fan, duct and air

flow meter. Run pressurising fan to maintain a specified internal air static pressure.

Measure steady inflow rate, this is building airtightness measurement.

171. Air dry bulb temperature is measured by:

1. Suspending a sensor about 1.0 m below the ceiling and waiting for it to stabilise.

2. Reading the building management system computer screen data from a fixed sensor in

the room.

3. Leaving a sling psychrometer on a desk for an hour.

4. Shielding a mercury in glass thermometer from room air draughts.

5. Rotating a sling psychrometer at head height in room air for one minute and taking an

immediate reading.

172. Which is not one atmospheric pressure?

1. 300 inches of mercury.

2. 1.0 bar.

3. 14.7 pounds per square inch, psi.

5. 1013.25 millibars, mb.

5. 101325 Pa.

173. Where could carbon monoxide, benzene and toluene gases have come from if detected

within an air conditioned low energy building?

1. Water chiller plant room refrigerant leakage.

2. Hydrocarbon natural gas combustion water heating plant.

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4. Cleaning fluids and off-gassing from furnishings.

5. Outside air intake to AHU or people smoking tobacco or cannabis.

174. Air dry bulb temperature is dependent upon:

1. People and furniture.

2. Size of room.

3. Radiation sources within the room.

4. Solar heat gain through the windows.

5. Air velocity in the room.

175. Which is correct about peak summertime temperature in buildings?

1. A low energy building is one that always overheats.

2. Victorian era houses and large buildings never overheat.

3. Any building anywhere in the world, even an igloo, can become overheated.

4. We have no idea why buildings become too hot, they are all ventilated.

5. Get used to it, the HM Government Carbon Plan 2011 will stop the widespread use of

air conditioning in the UK.

176. Atmospheric vapour pressure is:

1. The total pressure of the atmosphere at the time.

2. The pressure exerted on the ground by the dry gases of the atmosphere above sea level.

3. The sum of the clouds, wind and static air forces on the ground.

4. That part of the barometric pressure produced by the water vapour in humid air.

5. None of these.

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1. French Foreign Legion.


3. Cold water storage tanks.

4. Hot water storage cylinders.

5. Aerosols from cooling towers, shower heads, spray taps, spa baths and humidifiers.

178. Air conditioning engineers consider atmospheric air pressure to consist of which?

1. Polluted air.

2. Vapours, gases and water vapour.


4. Around 700.0 mb from dry clean gases, 200 mb from polluting vapours and dusts plus

113.0 mb due to water vapour.


179. Air quality within a building depends upon:

1. Number of people indoors.

2. How much and where air pollutants are found.

3. Relative humidity of room air.


5. Plants, animals and furnishings in the building.


1. Comfortably warm houses and offices.

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2. Less draught.

3. Suppression of house dust mites, condensation and mould growth due to warmer

environment.

4. Inadequate removal of house dust mites, condensation and potential mould growth.

5. Lower energy costs.


1. Spraying water into room air heats up the room.

2. Evaporating water consumes sensible heat energy.

3. Evaporating water consumes latent heat energy.

4. A room with a relative humidity of 25% feels humid.

5. Every air conditioning system must have a humidifier system.

182. What is air percentage saturation?

1. Water suspended in air relative to same quantity of liquid water.



4. Same as relative humidity.

5. A ratio.


1. Cigar smoke.

2. Carbon dioxide.

3. Benzene, toluene, formaldehyde and ethylene glycol.


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5. NOx.


1. Moisture in room air finds its own way out of the building.

2. Moisture gained by room air will always condense somewhere and drain away.

3. Moisture within building air will always condense into liquid at the lowest surface

temperature location.

4. Natural ventilation does not remove moist air from a building.

5. Only mechanical exhaust systems remove moist air from a building.

185. An anemometer is:

1. For measuring fan vane angles.

2. For assessing animosity towards the room conditions.

3. A calibrated device to measure air speed in a room, outdoors or in an air duct.

4. A rotating vane with thermistor or heated wire sensor.

5. Only to be used by qualified personnel.

186. In well-insulated non air conditioned buildings having modest glazing areas and little

air movement, which will operative temperature be closest to?

1. Globe temperature.


3. Wet bulb temperature.



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187. Which does not apply to heat stroke in a hot climate?

1. To avoid it, get into a swimming pool.

2. Occurs at a body temperature of 40.6oC.

3. Sweating ceases.

4. Body becomes involuntarily hyperactive.

5. Body becomes comatose, brain damage from reduced blood supply and death is

imminent.

Refrigeration systems

188. How could a chilled water cooling coil distribute bacteria into occupied air conditioned

rooms?

1. It cannot, as air temperature remains too cool.

2. It will not under normal operation.

3. Condensate water trap between drain tray and sewer always maintains a water seal.

4. Water seal in P-trap between drain tray and sewer may become dehydrated and allow

sewer gases to pass into the air handling unit and supply duct.

5. It will not when adequately maintained in accordance with codes and standards.

189. Which is a primary characteristic of a cooling tower?

1. Quiet operation.

2. Uses almost no water.

3. Potential source of water-based Legionella bacteria for outdoor air.

4. Compact unit usually installed within a chiller plant room.

5. Functions equally well in any outdoor climate.

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190. Which of these does a cooling tower not do?

1. Rejects heat from the building.

2. Cools condenser cooling water at 35oC when outdoor air is at 40°C d.b.

3. Cools the evaporator circuit.

4. Evaporates condenser water.

5. Only functions when outdoor air wet bulb temperature remains below incoming

condenser cooling water temperature.

191. Which might be a means of reducing the refrigeration system energy usage in a small

retail premises where food refrigeration, deep freezers and reverse cycle air conditioning are

all needed?

1. Install smallest capacity compressors possible.

2. Carry out frequent maintenance checks and parts replacement.

3. Switch reciprocating compressors off for as long as possible and maintain wide

temperature differentials.

4. Use same outdoor air cooled condenser for all three systems.

5. Variable refrigerant volume scroll compressor with software controlled digital operation

programmable for all variations in year round duties.







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193. What does CFC stand for?

1. Carbon fibre construction.

2. Carbon fibre cycle.

3. Confederation of fan constructors.

4. Chlorinate fire control.

5. Chlorinated fluorocarbons.

194. How is the coefficient of performance, COP, of a refrigeration system maximised?

1. Discharging waste heat to the atmosphere at the highest temperature.

2. Discharging waste heat to the atmosphere at the lowest temperature.

3. Evaporating refrigerant at the lowest possible temperature.

4. Evaporating refrigerant at the sametemperature as in the condenser.

5. Using the smallest possible temperature increase between evaporation and condensation

of the refrigerant.

195. Which term is used to describe the thermal efficiency of a refrigeration cycle?

1. ODP.

2. COP.

3. E%.

4. RE.

5. Qr.

196. How is the coefficient of performance of a refrigeration cycle calculated?

1. Heat rejected divided by the compressor output power.

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2. Heat absorbed divided by the refrigerating effect.

3. Refrigerating effect divided by the compressor input electrical power.

4. Heat absorbed plus heat rejected divided by compressor input power.

5. Compressor input power divided by condensing–evaporating temperature difference.

197. What is not a potential sink for heat rejected by the condenser of a refrigeration system?

1. Outside air.

2. River or sea water.

3. Sewer and surface water drain system flows.

4. Damp ground nearby.

5. Water circulation to other heat pumps requiring heating at the same time.

Sustainability



2. Everything used in the building’s service life comes from globally sustainable

resources.



5. The building has been constructed from organically grown materials.


1. All the glass in this building comes from self-sustaining resources.

2. All the aluminium in this building comes from self-sustaining resources.

3. All the primary energy used by this building comes from self-sustaining resources.

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4. All the concrete and reinforcing steel in this building comes from self-sustaining

resources and recycled materials.

5. None of these answers.


1. Buildings complying with agreed principles of economic, social and ecological

sustainability.

2. No hydrocarbon primary energy used in the construction of this building.

3. Design and construction workers on this building all cycled to work.

4. All building materials were harvested from the site and ground beneath the site.

5. The building is entirely heated and cooled from solar and wind energy collectors on the

site.


1. The computers in this building are all fully recyclable into new products in future years.

2. No harmful chemicals or materials were used in the manufacture or maintenance of the

computers in this building.

3. This building is less damaging to the environment than the similar but older building

alongside.

4. In 100 years or more, this building can be crushed and all its construction materials

recycled for a similar building.

5. The computers in this building are all made from recycled materials.


1. This design is repeatable.

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2. All the materials used in the construction of this building came from recycled resources.

3. Some of the materials used in the construction of this building came from recycled

resources.

4. The Board Room executive table within this building was made from floor boards

recycled from our previous demolished old fashioned building.

5. This new building has some surface materials the owners can boast about as recycled.

Temperature


1. Name of engineer who designed the first steam engine.

2. Unit of heat.

3. Measured in kJ/kg s.




1. Name of engineer who built bridges and railways in the UK in the 1800s.

2. Measurement of energy.

3. Measured in kJ/kg K.

4. Relative temperature scale.



1. Where absolute zero gravity starts.

2. Something to do with temperature.

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3. First name of Dr. K. Celsius.

4. oC + 273.

5. Engineer of the first closed circuit piped heating system.

206. Which is correct about Kelvin degrees?

1. Celsius scale plus 180

2. Are always negative values of Celsius degrees.

3. Symbol K.

4. Awarded by Kelvin University, Peebles, Scotland.

5. oC + 180.


1. Name of a famous Scottish scientist.

2. Invented first bicycle in Scotland.

3. K = °C + 273.

4. Kelvin McAdam invented tar macadam for road surfacing.

5. Degrees measured above absolute zero at −180oF.


1. Measurement of room air temperature.

2. Always used in heat transfer units.

3. Used to specify absolute temperature and temperature difference.

4. Fahrenheit plus 180.

5. Zero scale commences at −40oC.

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209. Which is correct about Celsius?

1. Latin name of inventor of Roman hypocaust under floor heating system in 200 BC.

2. Fahrenheit minus 32.

3. °C = (°F − 32) × 59.

4. °C = (°F + 32) × 59.

5. °C = (°F × 32) × 95− 180.


1. Called oC units.

2. Kelvin degrees plus 273.13.

3. Kelvin minus 180.

4. Commonly used for cryogenic applications.

5. °C = (°F − 180) × 59.


1. Temperature scale in the centimetre, gram, second (CGS), metric system.

2. Name of the Roman Senator in 35 AD who stabbed Caesar.

3. Normal body temperature is 41oC.

4. Defines normal human body temperature of 98.4 degrees.

5. Temperature scale in the metre, kilogram, second (MKS), metric system.

Thermal comfort

212. Thermal comfort PPD means?

1. Personal preferences determined.

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2. Personal preferences determination.

3. Has no meaning.

4. Percentile people dissatisfied.

5. Predicted percentage of dissatisfied people.

Ventilation

213. How is air leakage by a building measured?

1. Anemometer readings at every opening to outdoors.

2. Fill with smoke and time taken to fully disperse.

3. Cannot be done at all.

4. Large fan sucks air out of whole building at −50 Pa and flow measured.

5. Large fan pressurises building at 50 Pa and flow measured.

214. The required air leakage rate from a new building is in the range:

1. Half to one air change per hour.

2. 0.25 air changes per hour.

3. 1 to 10 m3/h m2 at 50 Pa internal air pressure.

4. 10 to 100 m3/h m2 at 25 Pa internal air pressure.

5. Must be zero.

Volume

215. Which is correct about volume?

1. 1 cubic centimetre water occupies 1 litre.

2. 1 tonne of water occupies 1000 m3.

3. 1 m3 = 1000 litre.

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4. 1 litre of water weighs 100 kg.

5. 1 litre of water weighs 10 kg.


1. 1 m3 air weighs around 100 kg.



4. 1 litre occupies 1 m2 area and 100 mm height.



1. 1 litre water is contained in a cube of 100 mm sides.

2. 1 litre air is contained in a cube of 1000 mm sides.

3. There is no such a thing as a volume sensor for a control system.

4. 100 concrete blocks of 300 mm × 200 mm × 100 mm occupy a volume of 6 m3.

5. 1 tonne water occupies 10 m3.

218. A room 12 m long, 8 m wide and having an average height of 4 m, has a volume of

which?

1. 400 m3.

2. 62 m3.

3. 462 m3.

4. 384 m3.

5. 192 m3.

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219. Which is the correct length of a 1200 m3 sports hall of average height 4 m and width 12

m?

1. 25 m.

2. 10 m.

3. 250 m.

4. 120 m.

5. 12.5 m.

220. What have I learnt from this study?





4. The building will work without the mechanical and electrical services anyway.

5. I now appreciate the importance and main features of the essential and desirable

building services!

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14 Understanding units

Density










3. 0.802 m3/kg.

4. 1.205 kg/m3 at 20oC, 1013.25 mb.

5. 5.67 kg/m3.



2. 1013.25 m3/kg.

3. 101325 kg/m3.

4. 1.205 MJ/m3 K.

5. 1000 kg/m3 at 4oC.


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1. 1.205 × 105 kg/m3.


3. 1.012 × 103 kJ/m3.

4. 1.27 kJ/kg K.

5. 100 g/cm3.


1. 1 g/cm3.

2. 1.2 × 103 kg/m3.



5. 1 kg per litre.

Electrical

7. Which of these has the correct electrical units?

1. 1 MW =103 W.

2. 103 kJ = 103 kW/s.

3. 1 W = 1 V × 1 A.

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4. Electrical energy meters accumulate kW/h.

5. 103 W = 103 V × 103 A.


1. 103 kW/h = 103 × 3600 W/s.

2. kWh = energy.

3. 1 GJ = 106 V × 1 A.

4. 1 MJ = 106 V × 1 A.

5. 1 kJ/s = 103 V × 1 A.


1. 103 W = 103 V × 1 A.

2. 1 MWh = 103 Ws.

3. 1 kWh = 103 Ws.

4. 1 kWh = 1000 W/s.

5. 1 kWh = 1000 W/h.

Energy


1. Sensible heat content kJ/kg.

2. Total heat content kJ/kg.

3. 1.205 kJ/kg.

4. 1.012 kJ/kg K.

5. 4.186 kJ/kg K.

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1. Ratio of 𝐶p𝐶v

.



4. 1.012 kg K/W.

5. 1.012 kJ/kg K.


1. 1.013 kW/kg K.

2. 1.012 MJ/kg K.

3. 4.186 kg K/kW.

4. 4.186 kJ/kg K.

5. 4.2 kg K/kJ.



2. 4.19 kW s/kg K.

3. A ratio.

4. 1.102 kJ/kg K.


Frequency

14. Which has the correct meaning for frequency?

1. Number of times an event is repeated.

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2. Cyclic repetition of an event.

3. Number of complete rotations per unit time.

4. Statistical correlation.

5. Occasional reoccurrence.


1. Alternating current rate of increase.

2. Electrical single or three phase.

3. Torque of a motor.

4. Air changes per hour.

5. Revolutions per minute.

16. Which is not correct in relation to frequency?

1. 3000 RPM = 50 Hz.

2. 1 Hz = 1 Nm/s.

3. High frequency fluorescent lamps work at 20000 Hz.

4. VFD means variable frequency drive.

5. 60 Hz = 3600 RPM.


1. Number of times an event is repeated.

2. Frequently occurring.

3. Number of complete rotations per unit time.

4. Statistical correlation.

5. Occasional reoccurrence.

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1. Alternating current rate of increase.

2. Electrical single or three phase.

3. Torque of a motor.

4. Air changes per hour.

5. RPM.

19. Which is not correct in relation to frequency?

1. 3000 RPM = 50 Hz.

2. 1 Hz s= 1 Nm/s.

3. High frequency fluorescent lamps work at 20000 Hz.

4. VFD means variable frequency drive.

5. 60 Hz = 3600 RPM.

General knowledge

20. Which of these is the acceleration due to gravity, g?

1. 10 m/s2.

2. 30 ft/s2.

3. 186000 miles per hour.

4. Gravity is static.

5. 9.807 m/s2.

21. Which of these describes the acceleration due to gravity, g?

1. Calculated from a 1 kg weight free falling from a height.

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2. Relative to distance from the Moon.

3. Constantly 9.807 m/s2.

4. Varies with height above sea level.

5. Inversely proportional to depth below sea level.

22. Which of these is the acceleration due to gravity, g?

1. 9.807 km/s2.

2. 9.807 ft/s2.

3. Speed of light.

4. Gravity acceleration varies with height above ground level.

5. 9.807 m/s2.

23. Which of these describes the acceleration due to gravity, g?

1. Calculated from anyweight free falling.

2. Varies duringMoon cycle around Earth.

3. 32.2 ft/s2.

4. Varies with tidal position.

5. Cannot be measured precisely.

24. Which of these has the correct units?

1. Mass is measured in kilos.

2. 1 tonne = 106 kg.

3. 1 kg = 109 mg.

4. 103 kg/m3 = 1 kg/l.

5. 106 m = 1 km.

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25. Which of these are not correct?

1. 1 hour = 3600 seconds.

2. 60 hours = 3600 minutes.

3. 3.6 × 103 seconds = 1 hour.

4. 1 year = 8760 hours.


Heat transfer

26. Which is correct about the Stefan-Boltzmann constant?


2. 4.186 kJ/kg K.

3. 1.012 kJ/kg K.

4. 5.67 × 10-8 W/m2 K4.



1. Sensible heat content kJ/kg.

2. Total heat content kJ/kg.

3. 1.205 kJ/kg.

4. 1.012 kJ/kg K.

5. 4.186 kJ/kg K.


1. Ratio of Cp/Cv.

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4. 1.012 kg K/W.

5. 1.012 kJ/kg K.


1. 1.013 kW/kg K.

2. 1.012 MJ/kg K.

3. 4.186 kg K/kW.

4. 4.186 kJ/kg K.

5. 4.2 kg K/kJ.



2. 4.19 kW s/kg K.

3. A ratio.

4. 1.102 kJ/kg K.


31. Which is correct about the Stefan–Boltzmann constant?


2. 4.186 kJ/kg K.

3. 1.012 kJ/kg K.

4. 5.67 × 10-8 W/m2 K4.


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3. 0.802 m3/kg.

4. 1.205 kg/m3 at 20oC, 1013.25 mb.

5. 5.67 kg/m3.



2. 1013.25 m3/kg.

3. 101325 kg/m3.

4. 1.205 MJ/m3 K.

5. 1000 kg/m3 at 4oC.




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1. 1.205 × 105 kg/m3.


3. 1.012 × 103 kJ/m3.

4. 1.27 kJ/kg K.

5. 100 g/cm3.


1. 1 g/cm3.

2. 1.2 × 103 kg/m3.



5. 1 kg per litre.

Mathematics


1. A logarithm.



4. 2.718.

5. Has no meaning.

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2 e = 10𝑥.

3. The sum of an infinite series.

4. e = √−1.

5. e1 = 2.718.


1. An integral.



4. 2.718.

5. Has no meaning.



2. e = 10x.

3. A Fibonacci number.

4. e = √−1.

5. e1 = 2.718.

Pressure

42. Which of these equals one standard atmosphere at sea level?

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1. 1.013 tonne/m2.

2. 1 bar.

3. 10000 N/m2.

4. 1013.25 mb.

5. 106 N/m2.


1. 1013 tonne/m2.

2. 105 bar.

3. 109 N/m2.

4. 14.7 lb/in2.

5. 106 N/m2.


1. 1 × 105 pascals, Pa.

2. 1.01325 × 105 N/m2.

3. 1 × 104 N/m2.

4. 30 m H2O.

5. 1013.25 mm Hg.


1. 9.807 m H2O.

2. 29.35 m H2O.

3. 10.3 m H2O.

4. 101325 kJ/m2.

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5. 1.205 kg/m2.


1. 1 atmosphere =103 b.

2. 1 Pascal = 1 N/m2.

3. Pascal is a unit of radiation measurement.

4. 1 kN/m2 = 1 b.

5. 1 mb = 103 N/m2.

47. Which of these has the correct pressure units?

1. 1.01325 mb = 1 atmosphere.

2. 1 MN = 103 kN/m2.

3. 1 b = 1 kN/m2.

4. 13.6 mb = 13.6 N/m2.

5. 1 b = 105 N/m2.


1. 1 mb = 1 N/m2.

2. 1 b = 103 mb.

3. 1 mb = 103 N/m2.

4. 103 kN/m2 = 1 b.

5. 1 mb = 106 b.


1. 1 Nm = 1 Pa.

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2. 1000 Pa = 1 atmosphere.

3. 1 kPa = 1 kN/m2.

4. 1 Pa = 1 mb.

5. 1 Pa = 1 N/m2.

50. What are the units for pressure drop rate in a pipeline?

1. m head H2O/m run.

2. N/m2.

3. mb/m.

4. N/m3.

5. kN/m3.

51. What does N/m3 stand for?

1. Nanometres per m2 pressure drop per metre run of pipe.

2. Neurons per cubic metre of room volume.

3. Newtons per square metre pressure drop per metre run of pipe or duct.

4. Newton per cubic metre is a density.

5. Nano-particles of radon gas per cubic metre of air in a building.

52. What does N/m3 stand for?

1. Normalised volumetric air change rate for a room.

2. Number of people in a building divided by building volume.

3. Volumetric coefficient.

4. Noise rating divided by room volume.

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5. Pressure drop rate in a pipe or duct.


1. 1000 tonne/m2.

2. 1 mbar.

3. 1 N/m2.

4. 1.01325 b.

5. 104 N/m2.


1. 1000 tonne/m2.

2. 107 bar.

3. 106 N/m2.

4. 14.7 lb/in2.

5. Cannot be precise as sea levels change all the time

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Temperature


1. Name of engineer who built Cornish beam engines in the 1800s.

2. Unit of heat.

3. Founded specific heat capacity definition.

4. Devised first comfort scale.



1. Where absolute zero gravity starts.

2. Something to do with temperature.

3. First name of Dr. K. Celsius.

4. oC + 273.

5. Engineered the first closed circuit piped heating system.


1. Celsius scale plus 180.

2. Are always negative values of Celsius degrees.

3. Symbol K.

4. Awarded by Kelvin University, Peebles, Scotland.

5. K = °C × 95

+ 32.


1. Name of a famous Scottish scientist.

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2. Invented first bicycle in Scotland.

3. K = °C + 273.

4. Kelvin McAdam invented tarmacadam for road surfacing.

5. Degrees measured above absolute zero at −180oF.


1. Measurement of room air temperature.

2. Always used in heat transfer units.

3. Used to specify absolute temperature and temperature difference.

4. Fahrenheit plus 180.

5. Zero scale commences at −40oC.


1. Latin name of inventor of Roman hypocaust under floor heating system in 200 BC.

2. Fahrenheit minus 32.

3. °C = °F × 59

+ 32.

4. °C = 32 − °F × 59.

5. °C = (°F − 32) × 59.


1. Called oC units.

2. Kelvin degrees plus 273.13.

3. °C = (°F + 32) × 59.

4. Commonly used for cryogenic applications.

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5. °F = (°C − 32) × 95.


1. Temperature scale in the centimetre, gram, second (CGS), metric system.

2. Name of the Roman Senator in 35 AD who stabbed Caesar.

4. °C = (°F − 180) × 59 .

4. Defines normal human body temperature of 98.4 degrees.

5. Temperature scale in the metre, kilogram, second (MKS), metric system.


1. Name of engineer who designed the first steam engine.

2. Unit of heat.

3. Measured in kJ/kg s.



Units

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1. 1 newton = 1 kg × 1 m/2.

2. 1 joule = 1 kg × 1 m.

3. 1 watt = 1 kg × g m/s2.

4. 103 joules = 3600 kN/m2.

5. 1 joule = 1 N/m2.


1. 1 joule = 1 newton × 1 metre.

2. 1 joule = 1 watt/s.

3. 103 J = 1 kW/s.

4. 1 watt = 103 joule/s.

5. 1 MJ = 103 kW/s.


1. 1 W = 1 Nms.

2. 1 W = 1 Js.

3. 1 W/s = 103 J.

4. 1 W = 1 Nm/s.

5. 1 kW/h = 103 J/h.


1. Mass is measured in kilos.

2. 1 tonne = 106 kg.

3. 1 kg = 109 mg.

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4. 103 kg/m3 = 1 kg/l.

5. 106 m = 1 km.

68. Which of these are not the correct units?


2. 60 hours = 3600 minutes.

3. 3.6 × 103 seconds = 1 hour.

4. 1 year = 8760 hours.



1. 1 MW =103 W.

2. 103 kJ = 103 kW/s.

3. 1 W = 1 V × 1 A.

4. Electrical energy meters accumulate kW/h.

5. 103 W = 103 V × 103 A.


1. 103 kW/h = 103 × 3600 W/s.

2. kWh = energy.

3. 1 GJ = 106 V × 1 A.

4. 1 MJ = 106 V × 1 A.

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5. 1 kJ/s = 103 V × 1 A.


1. 103 W = 103 V × 1 A.

2. 1 MWh = 103 Ws.

3. 1 kWh = 103 Ws.

4. 1 kWh = 1000 W/s.

5. 1 kWh = 1000 W/h.


1. 1 atmosphere =103 b.

2. 1 pascal = 1 N/m2.

3. Pascal is a unit of radiation measurement.

4. 1 kN/m2 = 1 b.

5. 1 mb = 103 N/m2.

Volume


1. 1 cubic centimetre water occupies 1 litre.


3. 1 m3 = 1000 litre.

4. 1 litre water weighs 100 kg.

5. 1 litre water weighs 10 kg.


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1. 1 litre water is contained in a cube of 100 mm sides.

2. 1 litre air is contained in a cube of 1000 mm sides.

3. There is no such a thing as a volume sensor for a control system.

4. 100 concrete blocks of 300 mm × 200 mm × 100 mm occupy a volume of 6 m3.


76. A room 12 m long, 8 m wide and having an average height of 4 m, has a volume of?

1. 400 m3.

2. 62 m3.

3. 462 m3.

4. 384 m3.

5. 192 m3.

77. Which is the correct length of a 1200 m3 sports hall of average height 4 m and width 12

m?

1. 25 m.

2. 10 m.

3. 250 m.

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4. 120 m.

5. 12.5 m.

. 78. What have I learnt from this study?





4. The building will work without the mechanical and electrical services anyway!

5. I now appreciate the importance and main features of the essential and desirable

building services!

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The End

Instructors Manual for 6th edition - Amazon Web...

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