Lighting system design

Lighting Design Objectives:

Ensure safety and health.

Performance quantity and quality.

Appearance and comfort.

Lighting Design Procedures:

Consideration of space function.

Provision of quality and quantity of illumination.

Selection of lighting system components .

Consideration of economics.

Lighting System Classification by Layout:

Uniform (general) lighting system.

Localized lighting system.

Local lighting system.

Classification by Luminaire Type:

Direct:

creates shadows, direct glare, and reflected glare

Classification by Luminaire Type: Indirect:

The entire ceiling becomes a light source, thus eliminating shadows and glares.

good in an office and schoolrooms

Classification by Luminaire Type:

Semi-direct:

The globe is good for stairways, corridors, and storage areas.

Classification by Luminaire Type:

Semi-indirect:

This fixture gives a good overall lighting with low surface brightness and low glare.

Classification by Luminaire Type:

General diffuse:This type of globe can be bad because of excessive

brightness and glare .

Lamp choice:

Depends on the lamp characteristics with respect to the requirements of the application.

General considerations Light output.Luminous efficacy.Color temperature.Color rendering index.Rated life.Cost

Lighting Calculations Steps:

A. Objective and specifications:

B. Light loss factors.

A. Calculations.

A. Objective and specifications:

1. Seeking task.

2. Quantity required.

3. Area atmosphere.

4. Selection of luminaire. back

B. Light loss factors:

1. Luminaire ambient temperature .

2. Voltage to luminaire.(1% luminous change for each 2.5% voltage change).

3. Ballast factor.

4. Luminaire surface depreciation.

B. Light loss factors:

5. Room surface dirt depreciation (RSDD).

6. Burnouts (depends on the re-lamping program).

7. Lamp lumen depreciation (LLD).

8. Luminaire dirt depreciation (LDD).

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C. Calculations:

Total light loss factor (LLF) product of all contributing factors.

Required luminaires using LLF, selected components, required average lux.

Lay out distribution of luminaires to have uniform lighting.

Average illumination Calculated at the work plane.

Example on hand calculations:

Design of a machinery room of rectangular shape with 17.95mX27.00m dimensions.

27.00m

17.59m

Example on hand calculations:

Average LUX for this application is 200 LUX.

Required lumens = average LUX * Area

= 200 X 17.59 X 27 = 94986 lumens.

Total output lumens =

Lamp lumens X MF X CU X number lamps

Where:

MF (maintenance factor) = LLD X LDD X BOR X VD

CF is the coefficient of utilization.

Example on hand calculations:

Determination of CU

It is found from the factors RCR, CCR and FCR. where,

Example on hand calculations:

Example on hand calculations:

Example on hand calculations:

For the discussed example:

hcc=1m , hrc=2.7 m and hfc=0.8m

So that,

RCR=1.27

CCR=0.469

FCR=0.3755

Reflectance factors:

ceiling (ρc) : for rough light paint 0.3

walls (ρw) : for rough light paint 0.3

floor (ρf) : for dark concrete 0.2

From table CU = 0.57

Example on hand calculations:

MF = 0.6 X 0.8 X 0.975

LLF = MF X CU = 0.26675

Using fluorescent lamp, 2 lamps per luminaire, day light lamp and each lamp is 36 W

Lumens per lamp = 2500 lumen

94986 = N X 2500 X 0.2667

N = 144 lamp

Example on hand calculations:

Luminaires distribution:

the most common distribution of luminaires is the uniform distribution which have some rules distance from luminaire to wall = half the distance between rows Minimum number of rows = room width / maximum allowed spacing Maximum allowed spacing is found so as to have equal illumination at

the point in the mid distance between two luminaires (Q) and point directly under one luminaire ( P).

Example on hand calculations:

P Q

Lighting Design Using Software:

Open the DIALUX program

Then select the category required

The window will have the following shape:

Select edit room geometry icon, then press ok

Select the setting of general options:

Adjust the general options required:

Import the Auto-cad file:

Select the setting of gravity centre:

The file will be added to the DIALUX window:

Edit the room geometry to be justified to the imported file:

Adjust the surface reflection factor:

Adjust the maintenance and design factors:

Place the furniture :

Select the project luminaire: 1- Open the data base

Select the project luminaire: 2- Choose the suitable luminaire then press apply

Select the luminaire lay out:

Start calculations:

Judge the result according to the required lighting considerations and modify the lay out if necessary:

Take the final scene that will be rendered:

Some professional examples:

Some professional examples:

Some professional examples:

Some professional examples:

Some professional examples: