Public Schools HVAC Assessment

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Final Report

Town of Andover

Public Schools HVAC Assessment

September 2020

Submitted By: NV5

Carol Donovan, Director Michael Papagni, PE

200 Brickstone Sq. #201 Andover, MA 01810

Submitted To: Town of Andover Andrew Flanagan, Town Manager Sheldon Berman, Superintendent Janet Nicosia, Director of Facilities 5 Campanelli Drive Andover, MA 01810

Table of Contents

Town of Andover Page 1 of 39

School HVAC Assessments September 28, 2020

Section Page

1.0 Executive Summary ...................................................................................................................... 2

2.0 HVAC Assessment Methodology .................................................................................................. 9

3.0 Facility Descriptions and Assessments ..................................................................................... 14

3.1 Andover High School................................................................................................................... 14

3.2 Doherty Middle School ............................................................................................................... 16

3.3 West Middle School .................................................................................................................... 18

3.4 Wood Hill Middle School ............................................................................................................ 20

3.5 Bancroft Elementary School ...................................................................................................... 22

3.6 High Plain Elementary School ................................................................................................... 25

3.7 Sanborn Elementary School ...................................................................................................... 27

3.8 South Elementary ....................................................................................................................... 29

3.9 West Elementary School ............................................................................................................ 31

3.10 Shawsheen Preschool ................................................................................................................ 34

4.0 General Observations ................................................................................................................. 36

5.0 Recommendations and Next Steps........................................................................................... 38

Executive Summary



1.0 Executive Summary

Introduction and Project Overview:

NV5 was retained by the Town of Andover to assess the current status of the HVAC systems

serving their public schools. The school district consists of ten (10) schools: one preschool, five

elementary schools, three middle schools and one high school. Woodhill Middle School and

High Plain Elementary School were constructed as one building but act as two schools with

shared common areas. The list of schools assessed with approximate gross square footage and

year built is provided below.

Table 1 – School Data Summary

Building Name

Gross

Square

Footage

Number

of Stories

Year

Built

Year of Last

Renovation

Andover High School 315,000 3 1966 1995

Doherty Middle School 125,000 2 1951 1995

West Middle School 106,000 2 1956 1990

Bancroft Elementary School 105,000 3 2014

Sanborn Elementary School 51,560 1 1951 1995

South Elementary School 65,800 1 1957 1995

West Elementary School 94,000 1 1951

Woodhill Middle/ High Plain Elementary Schools 176,000 3 2002

Shawsheen Pre School 38,500 2 1923

The overall objective of the HVAC assessment was to conduct an independent survey of the

ventilation systems serving each school and determine if the systems were functioning properly

and are meeting or exceeding the current ASHRAE (American Society of Heating, Refrigerating,

Air Conditioning Engineers) Guidance for the Re-opening of Schools.

ASHRAE is a global professional society committed to serve humanity by advancing the art and

science of heating, ventilating, air conditioning, refrigeration and their allied fields. ASHRAE

developed a task force to help determine the technical approach to address the challenges of

the COVID-19 pandemic and possible future epidemics. A summary of the key general

recommendations related to HVAC systems is described below.

Inspection and Maintenance: Assess the condition of systems and make necessary

repairs.

Ventilation: A good supply of outside air, in accordance with ASHRAE Standard 62.1-

2019, to dilute indoor contaminants is a first line of defense against aerosol

transmission. Pre and post occupancy purge cycles are recommended to flush the

building with clean air.

Executive Summary



Filtration: Use of at least MERV-13 rated filters is recommended if it does not adversely

impact system operation. If MERV-13 filters cannot be used, including when there is not

mechanical ventilation of a space, portable HEPA filters in occupied spaces may be

considered.

Air Cleaning: Air cleaners such as germicidal ultraviolet air disinfection devices may also

be considered to supplement ventilation and filtration. Technologies and specific

equipment should be evaluated to ensure they will effectively clean space air without

generating additional contaminants or negatively impacting space air distribution.

Energy Use Considerations: In selecting mitigation strategies, consideration should be

given to energy use as there may be multiple ways to achieve performance goals that

have greatly different energy use impact. Control changes and use of energy recovery to

limit or offset the effect of changes in indoor air ventilation rate and filter efficiency may

reduce or offset energy and operating cost penalties.

Project Goals and Objectives:

Based on a review of the ASHRAE recommended guidelines and collaboration with the Andover

Department of Facilities, an overall achievable scope of work to address the technical

challenges for this project was developed with the town and is summarized below.

Review of design documentation provided by the Town for each school including original

drawings, HVAC upgrade drawings, retro-commissioning reports and additional

applicable reports referencing the original design intent.

Review of preventative maintenance program including master schedules and process

flow of work orders and routine preventative maintenance activities.

Assessment of all of the major air handling units (AHUs) including roof tops units (RTUs)

providing ventilation air to the schools including but not limited to visual surveys for

cleanliness, functionality and control through the building automation system (BMS) and

review of the programmed sequences of operation impacting the supply of outside air to

the space.

Assessment of major ventilation equipment filter status and filter upgrades to MERV13

filtration.

Assessment of a percentage (to the extent possible) of the unit ventilators (UVs) serving

individual classrooms including but not limited to visual surveys for cleanliness,

functionality and controllability.

Collaboration with the Town’s Department of Facilities (Department) to review and

enhance the current building management’s programmed sequence of operations for

each school to enhance (to the extent possible) the quantity of outdoor air being

supplied to the space.

Assessment of programmed daily air flush pre and post occupancy and confirm

programmed occupancy schedules.

Assessment of the isolation rooms and dedicated airflow maintaining a negative space

pressurization.

Executive Summary



Review of CO2 monitoring where applicable and programmed maximum ppm set points.

Review of the Department’s intended future upgrades to each school and future

recommendations.

Project Timeline:

NV5 was contacted by the Department of Facilities on August 13th and reviewed the general

scope or work required to perform the HVAC assessment of each school prior to the return of the

teachers and students. The following week of August 17th through August 21st, NV5 received

documents for each school for review prior to the onsite assessment. NV5 collaborated closely

with the entire Department of Facilities over the following three weeks to get access through-out

each school and perform the onsite HVAC assessment. Daily updates on findings were

distributed to the Department via field reports and spreadsheets and the Departments staff

addressed and fixed identified deficiencies around the clock during this time.

NV5 Firm Profile and Qualifications:

NV5 Global, Inc. (NASDAQ: NVEE) is a provider of professional and technical engineering and

consulting solutions to public and private sector clients in the infrastructure, energy,

construction, real estate and environmental markets. NV5 primarily focuses on five business

verticals: construction quality assurance, infrastructure, engineering and support services,

energy, program management, and environmental solutions. The Company has over 2,000

employees and operates out of 102 locations nationwide and abroad.

NV5 Global Inc. acquired Richard D Kimball, Inc. referred to as RDK Engineers on or about the

summer of 2016 and RDK became fully integrated into the NV5 brand in the summer of 2018.

RDK was founded locally in 1897 and is headquartered in the Town of Andover and continues to

provide HVAC, electrical, plumbing and fire protection, telecommunications, audio visual,

security, commissioning and energy consulting services. We have just under 200 multi-

disciplined engineers and administrative professionals locally here in Andover. Although our

name has changed, we will continue to provide our clients with the same level of service that we

have for the last 120 years with more extended service offerings. We have been working with

the Town of Andover closely on a multitude of HVAC projects over the past 20 years.

As a nationally recognized premier provider of commissioning and retro-commissioning services,

we have a portfolio of more than 2,000 projects including over 200 LEED projects including

numerous projects involving K-12 schools. Our team has held multiple contracts with the

Massachusetts School Building Authority (MSBA) for the past ten years as one of their preferred

commissioning engineers. In addition, we have been a preferred commissioning and retro-

commissioning provider for the Department of Capital Asset Management (DCAMM) for the past

ten years. Recent additional K-12 experience includes:

MSBA, Dracut Senior High School Addition/Renovation, Dracut, MA

Executive Summary



MSBA, New Marathon High School, Hopkinton, MA

MSBA, New Glover Elementary School, Marblehead, MA

MSBA, New Winchester High School, Winchester, MA

MSBA, New Marshall Simonds School, Burlington, MA

MSBA, Southeastern Regional Vocational Technical High School, South Easton, MA

MSBA, Cape Cod Regional Vocation Technical High School, Harwich, MA

MSBA, Marblehead Village Elementary School Renovation, Marblehead, MA

MSBA, Sutton Middle High School Renovation/Addition, Sutton, MA

MSBA, Stoneham Middle School Addition/Renovation, Stoneham, MA

The Winsor School, Center for the Performing Arts and Wellness, Boston, MA

Boston Prep Charter School, Boston, MA

North Andover New High School, North Andover, MA

Town of Andover Department of Facilities Staffing:

The Town of Andover Department of Facilities employs 4.5 full time skilled tradespersons to

maintain and repair HVAC systems and equipment at Town and School buildings. These consist

of 2.5 HVAC mechanics, a plumber, and a boiler mechanic. They are overseen by a Building

Operations Manager, who is also an HVAC Technician. All of the HVAC mechanics have received

Johnson Metasys BMS training. The Department also employs a full time mechanical engineer

who designs systems, diagnoses issues, and oversees mechanical design contracts.

The Administration of work orders and inventory is handled by a full time Work Control

Coordinator and a full time Materials Coordinator. Six of these individuals are trained in using

the Johnson Controls Metasys BMS system, with 3 of them having completed expert level

programming training. All of these individuals work under the Director and Deputy Director of

Facilities, who evaluate metrics and develop long term capital projects in collaboration with

staff, and who also use the BMS.

The Department of Facilities utilizes the SchoolDude computerized management and

maintenance system (CMMS). Several modules of this platform are used to support and track

repairs and maintenance. SchoolDude Preventative Maintenance module automatically

generates detailed equipment maintenance work orders based on a best practice schedule

defined by the operations and maintenance manuals for building systems. SchoolDude

Maintenance module is a work order system which assigns work by craft directly to

tradespersons for repairs as needed. SchoolDude inventory module records inventory purchases

and assignments to work orders to rack costs. SchoolDude Energy Manager tracks energy use

for every building.

The Town of Andover provided their Preventative Maintenance (PM) reports that they are

currently maintaining for each HVAC system for our review before and during the assessment.

Executive Summary



HVAC Assessment Methodology:

NV5 was provided with full transparent access to the Town’s documentation records for each

building and the Metasys building management system (BMS) to review the programmed

sequences of operations and programmed setpoints for each of the Rooftop Units (RTU’s), Air

Handling Units (AHU’s), Heating and Ventilating Units (HV’s) and Unit Ventilators (UV’s), AC units

and exhaust fans serving the various school spaces.

In collaboration with the Department of Facilities, NV5 prioritized the assessment of the air

handling equipment and respective filter installations. In addition to the visual observations of

the equipment, NV5 exercised the functionality and operation of each RTU, AHU, HV and UV by

changing the operating parameters through the Metasys BMS. For UV’s, an approximate

sampling of 25% was performed and similar findings for UVs were provided to the Department

of Facilities and they continued with the inspection of the remaining UVs based on our findings

and recommendations. Deficiencies observed by NV5 were immediately put into the repair

work order process and addressed by the facilities staff.

The Department of Facilities and NV5 developed a priority rating to assign to the deficiency

issues during the onsite assessment. The highest priority issues were determined to be any

element related to impacting the volume of outside air volume being supplied to the space.

Summary of Findings:

The Table below outlines the total number of ventilation units serving each school and the

number of high priority and low priority issues identified. High priority issues were determined

as having potential to impact the performance of the unit and the quantity of outdoor air being

supplied to the space.

All high priority (HP) items were coordinated and turned over immediately to the Department of

Facilities staff where they began processing immediately. The facilities staff proactively

addressed and repaired 100% of all high priority issues and each issue was reviewed

independently with our onsite team. All high priority items were addressed and repaired by the

facilities staff prior to return of teachers and students and the start of school on September 16,

2020.

The Department of Facilities continuously worked on the remaining low priority (LP) issues with

a large percentage of these issues being resolved. It should be noted that Shawsheen pre-

school opened at a later date. The total number of unit ventilators provided in the Table below

was provided by the town. NV5 assessed an approximate 25% sampling at each school as

appropriate. The issues remaining to complete are deemed low priority issues. Many of the low

priority issues are the result of older systems and aged equipment reaching the end of useful

life.

Executive Summary



Table 2 – Ventilation Equipment Summary

Building Name

Total

No.

AHUs

Total

No. of

RTUs

Total

No. UVs

Total

No.

of

Issues

High Priority

Issues

Addressed

and

Repaired

Low Priority

Issues

Remaining to

Complete

Andover High School 14 14 70 31 4 14

Doherty Middle School 5 2 53 61 5 55

West Middle School 4 3 45 14 4 4

Bancroft Elementary School 10 ----- ---- 14 10 4

Sanborn Elementary School 3 9 20 9 5 3

South Elementary School 2 10 30 28 15 6

West Elementary School 10 ---- 20 39 8 4

Woodhill Middle /

High Plain Elementary

Schools

12 2 ---- 20 8 12

Shawsheen Preschool 1 ---- 4 4 4 0

In Summary, the Department of Facilities meets and in many cases exceeds the guidelines

outlined in the ASHRAE guidance for the reopening of schools. All of the AHUs and RTUs were

surveyed to the extent possible and all necessary repairs related to the supply of outside air

were fixed by the Department. Pre and post occupancy purge cycles have been incorporated for

every school through the BMS and outside air intake has been increased to provide a good

supply of outside air in accordance with ASHRAE Standard 62.1. Filters have been upgraded to

MERV-13 rated filters for AHUs and RTUs to the extent possible. Demand control ventilation

(DCV) strategies and other control strategies have been modified so as not to adversely impact

the amount of outside air delivered to the space.

Acknowledgements:

On all of our projects, NV5 strives to be a strong “team” player. We work collaboratively with our

clients to establish goals that will meet the client’s needs throughout the project while

understanding that every project is diverse with its own set of unique circumstances and

requirements such as this pandemic related HVAC assessment. NV5 would like to acknowledge

the outstanding support and transparent collaboration that was received from the Department

of Facilities staff during the rigorous and intensive 3 week onsite effort. They proactively stayed

on top of every request from our onsite team and addressed each issue as it was brought to

their attention and notably worked around the clock to complete this effort.

Executive Summary



Table 3 – Abbreviations and Acronyms

Abbr. Description

AHU Air Handling Unit

ASHRAE American Society of Heating, Refrigerating and Air-Conditioning

BAS Building Automation System

BMS Building Management System

CM Construction Manager

CO2 Carbon Dioxide

Cx Commissioning

CxA Commissioning Authority

DCV Demand Control Ventilation

DOA Dedicated Outside Air

ERV Energy Recovery Ventilator

HEPA High Efficiency Particulate Air

HV Heating & Ventilating Unit

HVAC Heating, Ventilation, and Air Conditioning

IDIQ Indefinite Delivery, Indefinite Quantity

O&M Operations and Maintenance

OA Outside Air

PM Preventative Maintenance

PPM Parts Per Million

QC Quality Control

RTU Roof Top Unit

TAB Testing, Adjusting, and Balancing

UV Unit Ventilator

VRF Variable Refrigerant Flow

WC Water Column

HVAC Assessment Methodology



2.0 HVAC Assessment Methodology

HVAC Assessment Means and Methods:

NV5 was provided with full transparent access to the Town’s documentation for each school

including construction drawings, preventative maintenance plans and other pertinent reports.

Refer to Table below for a comprehensive list of documentation. NV5 was also granted access

to the Metasys BMS in order to review the programmed sequence of operations and setpoints

for each of the RTU’s, AHU’s, HV’s and UV’s serving the various school spaces.

NV5 and the Department of Facilities prioritized assessment of all major air handling equipment

to be assessed in lieu of a sampling methodology. The reasoning for this determination is

based on the circumstance that these units typically serve a multitude of spaces and have a

larger potential to cross contaminate. Assessment of filter installations and filter upgrades

were also prioritized and verified to be MERV-13 where applicable for these units. A sampling of

the UV’s of approximately 25% was determined to be adequate in identifying similar issues for

the Department of Facilities to assess and then subsequently verify on the remaining units. The

UVs are standalone pieces of equipment that serve individual spaces or classrooms with a

controlled quantity of outdoor air supplied to the space, hence, less potential for cross

contamination. NV5 provided the facilities staff with the testing protocols to assess the

remaining UVs.

In addition to the visual onsite assessment, NV5 reviewed the functional operation of each RTU,

AHU, HV and UV by modulating and adjusting the programmed operating parameters through

the Metasys BMS. The intent in doing so was to verity that outdoor air and return air dampers

and actuators were modulating and functioning adequately and that the percent opening of the

associated outdoor air damper was within the desired specifications. Control sensors and

devices were reviewed for reasonable and adequate monitoring and reporting. NV5 did not

perform calibration of unit sensors.

The Department of Facilities generated a repair work order for all of the NV5 identified issues

including both low and high priority issues. The work orders were prioritized with the highest

priority assigned to those elements that would provide increased outside air to the spaces

served by the associated equipment.

Table 4 – List of School Documentation

Type of Document School Drawings - 64-AHU Vol 2 M-1.4 thru 87-AHU Vol 2 M6.2 Andover High School

2013.08.16 Andover High School - RCx Report Andover High School

Facility Drawings - Levels 1-4 Andover High School




Type of Document School CAD Construction Drawings - MEPFP Bancroft Elementary School

PDF Construction Drawings - MEPFP Bancroft Elementary School

Replace Main Office HVAC Project Equipment Scope Doherty Middle School

2018 Main Office AC - Plan of Sheetmetal Doherty Middle School

2019.05.03 Facilities Report FINAL Doherty Middle School

Split System Rev1 18952017_1347 Doherty Middle School

Drawings - 48 D-M1 thru 57 D-M10. Doherty Middle School

New offices - Mechanical 06.28.2017 Doherty Middle School

Facility Drawings - Levels B, 1, 2 Doherty Middle School

VRV Selection Report - Town of Andover School Phase 2 Doherty Middle School

2019.10.22 Sanborn, South & West MS - Study Report Revised Sanborn Elementary School

G-7113 - Andover Sanborn ES Café DCV 2019-04-11 Sanborn Elementary School

Drawings - 1998 HVAC 1 H1A thru HVAC 5 HVC Sanborn Elementary School

Library RTU - Trane Submittal Sanborn Elementary School

RTU 2015 New 1 Sanborn Elementary School

RTU 2015 New 2 Sanborn Elementary School

Drawings - 1961 023 HV1 thru 1961 025 HV3 Sanborn Elementary School

Facility Drawing Sanborn Elementary School

Cad Drawings - GER 0500 Heating Study Shawsheen Preschool

PDF Drawings - GER 0500 Heating Study Shawsheen Preschool

Cad Drawings - GER Heating Phase 1 Shawsheen Preschool

PDF Drawings - GER Heating Phase 1 Shawsheen Preschool

Cad Drawing - Steam to HW plan Shawsheen Preschool

PDF Drawing - Steam to HW plan Shawsheen Preschool

Cad Drawing - Fl Plans Combined Layout1 Shawsheen Preschool

PDF Drawing - Fl Plans Combined Layout1 (1) Shawsheen Preschool

Facility Drawings - Levels B, 1, 2 Shawsheen Preschool

2019.10.22 Sanborn, South & West MS - Study Report Revised South Elementary School

Drawings - As-Builts 54 H-1 thru 62 H-9 South Elementary School

Facility Drawing South Elementary School

PDF Drawings - Mechanical West Elementary School

Drawings - 1968 08 12 HV-1 thru HV-8 West Middle School

2013.03.22 HV System Upgrade West Middle School

2019.10.22 Sanborn, South & West MS - Study Report Revised West Middle School

Facility Drawings - Levels 1, 2 West Middle School

Drawings - 178 M0.1 thru 198 M5.3 Wood Hill Middle - High Plain Elementary

17062.00 Andover School AC Project - Bid Drawings - 02-14-2018 Wood Hill Middle - High Plain Elementary

Facilities Drawings - Levels Lower, Main, Upper Wood Hill Middle - High Plain Elementary

Table 5 – List of Preventative Maintenance Documentation

Type of Document School Preventative Maintenance Master Schedule Andover High School Collins Center

Preventative Maintenance Master Schedule Bancroft Elementary School

Preventative Maintenance Master Schedule Doherty Middle School

Preventative Maintenance Master Schedule High Plain Elementary School

Preventative Maintenance Master Schedule Sanborn Elementary School

Preventative Maintenance Master Schedule Shawsheen Preschool

Preventative Maintenance Master Schedule South Elementary School

Preventative Maintenance Master Schedule West Elementary School

Preventative Maintenance Master Schedule West Middle School

Preventative Maintenance Master Schedule Wood Hill Middle School

School Preventative Maintenance 07.01.19-07.19.20 HVAC All schools

School Preventative Maintenance HVAC All schools




METASYS Building Management System (BMS):

The Town of Andover has chosen to utilize Johnson Controls Metasys Building Automation

System (BMS) for their building operations control. The BMS system is an intelligent

microprocessor based controller networks installed to monitor and control a buildings technical

HVAC systems and more. They allow the functionality of individual pieces of equipment to

operate as one integrated system. The entire system is made up of operator workstation, server

network, mircroprocessors, controllers, inputs and outputs to remotely monitor and control

locally mounted sensors and devices.

Typical System Components – Network

Web browser

Server

Workstation

Automation level controllers

Field level controllers

Operator terminals

Third party integrators

Room controllers

Programmed sequences of operations

Graphic displays

Alarms and notifications

Typical System Components – Field Devices

Airflow monitoring stations (CFM)

Temperature and humidity sensors

Damper actuators

Valve actuators

Airflow pressures

Water flow pressures

Carbon Dioxide sensors

Pumps, fans and motor status

Boiler and Chiller and Cooling tower status

Low level and high level connections

The Johnson Controls Metasys system is remotely monitored around the clock by the Andover

Department of Facilities trained staff. The BMS monitors and controls the day to day HVAC

operations of the school buildings and measures building performance. When building

parameters fall outside of their defined setpoints of performance, alarms and alerts are




generated for the facilities staff to address. The facilities staff has the ability to adjust setpoints

when deemed feasible and practical.

NV5 collaborated with the facilities staff with programming changes to be implemented in an

effort to maximize the amount of fresh outdoor air being supplied to the space.

Below are examples of the BMS interface typical for each school.

Bancroft Elementary School – BMS Main Page




Bancroft Elementary School – AHU-1

Bancroft Elementary School – HV-1

Facility Descriptions & Assessments



3.0 Facility Descriptions and Assessments

3.1 Andover High School

Existing HVAC System:

RTU’s serve the Field House, 3rd and 4th level Science classrooms, and the

Collins Center. AHU’ s serve the Kitchen, Lobby, Main Office, Health Office,

Library, Computer Labs, Lockers, Dunn Gym, Art Wing classrooms and Graphic

Arts classrooms. UV’s serve all perimeter classrooms (except for the Science

Labs), the Cafeteria, and 3rd level Teams room.

HVAC Assessment:

A total of 31 issues were identified at the Andover High School with 4 of these

issues determined to be high priority and the remaining deemed low priority.

100% of the high priority issues were addressed and repaired prior to teachers

and students returning to school on September 16, 2020. There are

approximately 14 low priority issues remaining to complete that the Department

of facilities is actively addressing.

Building Name Total No.

AHUs

Total No.

RTUs

Total No.

UVs

Total No.

of Issues

Andover High School 14 14 70 31

RTU’s and AHU’s: Units have been provided with 2” MERV 13 filters. Outside air

dampers were confirmed to be programmed for a Minimum Position of 75%

Outside Air (non-DCV) or 50% Outside Air (DCV). We identified various damper

positions that needed to be recalibrated.




Unit Ventilators: Units have been provided with 1” MERV 8 filters. Outside air


Outside Air (DCV). Various damper positions need to be adjusted. Various CO2

sensors were reading unreliable in the Metasys system and need to be

recalibrated. Subsequently, the Department of Facilities performed functional

testing of all the remaining unit ventilators.

BMS:

Andover High School – AHU-2

Andover High School – UV - Room 375




3.2 Doherty Middle School


RTU’s serve the Auditorium and Faculty Dining. AHU’s serve the Lockers, Gym

and Music Rooms. UV’s serve the Library, Offices and all classrooms. Variable

Refrigerant Flow (VRF) with Energy Recovery Ventilator (ERV) systems serve the

Main Office and Student Services.

HVAC Assessment:

A total of 61 issues were identified at the Doherty Middle School with 5 of these







AHUs

Total No.

RTUs

Total No.

UVs

Total No.

of Issues

Doherty Middle School 5 2 53 61

Heating and Ventilating (HV) Units: Units have been provided with 2” MERV 13

filters, with the exception of HV-1, which has 2” MERV 8 filters. Filters for this unit

need to be upgraded. Outside air dampers were confirmed to be programmed for

a Minimum Position of 75% Outside Air (non-DCV) for HV-4 and HV-5. For HV-2

and HV-3 which serve the Gym, the dampers were found to be programmed to a

minimum of 25% outside air. The minimum damper positions for these units

should be increased to 75% outside air. For HV-6, when the mixed air dampers

were commanded 100% open, the mixed air dampers were closer to 40% open.




The damper linkage should be adjusted as necessary so that the mixed air

dampers modulate to the commanded position.



Outside Air (DCV). The CO2 reading for UV-121 was zero (0). This CO2 sensor

operation needs to be reviewed.

BMS:

Doherty Middle School – UV – Classroom 120




3.3 West Middle School


RTU’s serve the Library, Cafeteria, Kitchen and Lecture Hall. AHU’s serve the

Auditorium and Gym. UV’s serve all perimeter classrooms (except the Lecture

Hall), Weight Room, Locker Rooms, Main Office and Health Office.

HVAC Assessment:

A total of 14 issues were identified at the West Middle School with 4 of these







AHUs

Total No.

RTUs

Total No.

UVs

Total No.

of Issues

West Middle School 4 3 45 14

RTU’s and AHU’s: Units have been provided with 2” MERV 13 filters. Outside air


Outside Air (DCV). Various AHU’s dampers were being commanded 0% open

during occupied mode. It is unclear why the mixed air damper command was

below the programmed minimum position of 50%. The units may have been

operating in a warm-up mode. If this is the case, the warm-up mode should be

disabled. The programming governing the control of the mixed air dampers

should be reviewed and revisions should be made to ensure that during occupied

mode, the mixed air damper command never drops below 50%. RTU-9 was

observed to be de-energized when commanded to occupied mode. The unit may

not have power. Outdoor air control could not be verified for this unit.






Outside Air (DCV). In general, the mixed air dampers were observed to modulate

to the commanded position. For UV-309, the filter was observed to be dirty and

should be replaced.

BMS:

West Middle School – UV – Classroom 101




3.4 Wood Hill Middle School


RTU’s serve the Dining area and Music/Fitness rooms. AHU’s serve the

remainder of the building.

HVAC Assessment:

A total of 20 issues were identified at the Wood Hill Middle School with 8 of

these issues determined to be high priority and the remaining deemed low

priority. 100% of the high priority issues were addressed and repaired prior to

teachers and students returning to school on September 16, 2020. There are


of facilities is actively addressing. It should be noted that total counts for Wood

Hill Middle School incorporate total counts for High Plain however the buildings

were assessed separately.


AHUs

Total No.

RTUs

Total No.

UVs

Total No.

of Issues

Wood Hill Middle School 12 2 --- 20

AHU’s: AHU-1 has been provided with 2” MERV 13 Pre-filters, 4” MERV 13 HEPA

outside air filters and 2" MERV 13 return air filters. AHU-2 and AHU-3 have been

provided with 2” MERV 13 Pre-filters, 4” MEPA outside air filters and 2" MERV 13

return air filters. AHU-6 and AHU-7 have been provided with 2" MERV 13 and 12"

MERV 11 HEPA filters. AHU-1, AHU-2 and AHU-3 are 100% outside air units. For

AHU-6, the mixed air damper command was 25% with a CO2 reading of 2016

ppm. It does not appear that the unit is utilizing the CO2 reading, or the sensor

may be deficient, or thee unit may not be utilizing a CO2 sensor. It should be

confirmed if this unit is utilizing the DCV programming. If so, the AHU-6 minimum

mixed air damper command should be increased to 50%. For AHU-7, the mixed

air damper command was 100% with a CO2 reading of 504 ppm. It does not




appear that the unit is utilizing the CO2 reading. The dampers remain at 100%

open even with the outside air temperature above the economizer setpoint.

RTU’s: Units have been provided with 2” MERV 13 and 12” MERV 11 HEPA filters.

The minimum mixed air damper commands are programmed to 50%. It is

unclear if the RTU’s are utilizing the CO2 readings. For RTU-1, one of the outside

air dampers remained closed at all times regardless of the damper position

command.

BMS:

Wood Hill Middle School – AHU-1




3.5 Bancroft Elementary School


AHU’s serve the entire building.

HVAC Assessment:

A total of 14 issues were identified at the Bancroft Elementary School with 10 of







AHUs

Total No.

RTUs

Total No.

UVs

Total No.

of Issues

Bancroft Elementary

School 10 ----- ---- 14

AHU’s: Exceptions to the filter change out were noted as follows: AHU-3 was

noted to have 2" MERV 8 installed in the pre-filter rack and final filter rack. AHU-

5 was noted to have 2" MERV 8 filters installed in the return air filler rack, pre-

filter rack and final filter rack. AHU-6 was noted to have 2" MERV 8 filters. The

installed MERV 8 filters in these AHU systems should be replaced with MERV 13

filters.

For AHU-1 through AHU-8, the demand control ventilation programming had not

yet been updated. The programming should be updated to reset the mixed air

damper command from 50% to 100% as the return air CO2 rises from 600 ppm

to 800 ppm. The majority of units were observed to utilize CO2 setpoints of 800

ppm and 1000 ppm and a minimum mixed air damper command below 50%.

HV Units: Exceptions to the filter change out were noted as follows: HV-2 was

noted to have 2" MERV 8 filters. The installed MERV 8 filters should be replaced




with MERV 13 filters. For the HV Units, the demand control ventilation

programming had not yet been updated. The programming should be updated to

reset the mixed air damper command from 50% to 100% as the return air CO2

rises from 600 ppm to 800 ppm. The majority of units were observed to utilize

CO2 setpoints of 800 ppm and 1000 ppm and a minimum mixed air damper

command below 50%.

BMS:

Bancroft Elementary School – BMS Main Page




Bancroft Elementary School – AHU-1

Bancroft Elementary School – HV-1




3.6 High Plain Elementary School


RTU’s serve the Dining area and Music/Fitness rooms. AHU’s serve the

remainder of the building.

HVAC Assessment:

A total of 20 issues were identified at the High Plain Elementary School with 8 of





of facilities is actively addressing. It should be noted that total counts for Wood

Hill Middle School incorporate total counts for High Plain however the buildings

were assessed separately.


AHUs

Total No.

RTUs

Total No.

UVs

Total No.

of Issues

High Plain Elementary 12 2 --- 20

AHU’s: AHU-8 has been provided with 2” MERV 8 and 12” MERV 11 HEPA filters.

AHU-4 and AHU-5 have been provided with 2" MERV 13 and 4" MEPA outside air

filters, and 2" MERV 13 return air filters. AHU-4 and AHU-5 are 100% outside air

units. AHU-8 was not operating due to its associated return fan VFD being offline

in alarm. AHU-8 appears to have a minimum mixed air damper command of

10%. The AHU-8 DCV programming appears to require updating.

HV Units: Units have been provided with 2” MERV 8 Pre-Filters and 12” MERV 11

HEPA filters. For HV-1, the mixed air damper command was 50% with a CO2

reading of 986 ppm. It does not appear that the unit is utilizing the CO2 reading.

For HV-2, the mixed air damper command was 25% with a CO2 reading of 703

ppm. It does not appear that the unit is utilizing the CO2 reading. It should be




confirmed if these units are utilizing the DCV programming. If so, the HV-2

minimum mixed air damper command should be increased to 50%.

BMS:

High Plain Elementary School – AHU-4




3.7 Sanborn Elementary School


RTU’s serve the Main Office, Special Education offices, Library, Computer Room,

Music Room, Resource Rooms and all interior offices. AHU’s serve the

Cafetorium and Gym. UV’s serve all three wings of classrooms.

HVAC Assessment:

A total of 9 issues were identified at the Sanborn Elementary School with 5 of







AHUs

Total No.

RTUs

Total No.

UVs

Total No.

of Issues

Sanborn Elementary 3 9 20 9

RTU’s and AHU’s: Units have been provided with 2” MERV 13 filters with the

exception of AHU-5. AHU-5 was observed to be equipped with a mix of MERV 8

and MERV 13 filters. All MERV 8 filters should be replaced with MERV 13 filters.

For AHU-5, the outdoor air damper and return air damper do not appear to

modulate. The return air damper remains approximately 100% open and the

outdoor air damper remains approximately 50% open. There may be a

pneumatic leak at this unit. For Cafe Unit 1 and Cafe Unit 2, the return air

dampers does not appear to rotate. The linkages may be disconnected. Damper

operations should be reviewed and necessary actions taken to ensure that the

damper modulates to the commanded position. For RTU-1(A), RTU-1(B) (two

units are labeled RTU-1 on the roof), RTU-2, AHU-4, RTU-6 and RTU-7, the damper

commands are not available through Metasys. The mixed air dampers are




positioned for approximately 20% outdoor air. Minimum mixed air damper

commands should be increased to 75%. This may need to be programmed at the

unit’s packaged controller.



Outside Air (DCV). No deficiencies were noted for the Unit Ventilators that were

assessed.

BMS:

Sanborn Elementary School – AHU – Gymnasium

Sanborn Elementary School – UV – Classroom A1




3.8 South Elementary


RTU’s serve the Main office, Kitchen, Music, Chorus, Art, Interior Special

Education rooms and the Gymnasium. AHU’s serve the Cafetorium. UV’s serve all

perimeter classrooms, Nurse and Teacher’s Lounge.

HVAC Assessment:

A total of 28 issues were identified at the South Elementary School with 15 of







AHUs

Total No.

RTUs

Total No.

UVs

Total No.

of Issues

South Elementary 2 10 30 28

RTU’s: The majority of the units have been provided with 1” MERV 8 filters. The

packaged RTU’s may not have the capacity to handle the static pressure drop of

a 1” MERV 13 filter. This should be confirmed with the unit manufacturer. The

damper commands are not available through Metasys. The mixed air dampers

are positioned for approximately 20% outdoor air. Minimum mixed air damper

commands should be increased to 75%. This may need to be programmed at the

unit’s packaged controller.

HV Units (Cafetorium and Gymnasium): Units have been provided with 2” MERV

13 filters. The demand control ventilation programming needs to be updated to

reset the minimum mixed air damper command from 50% to 100% as the space

CO2 level rises from 600 ppm to 800 ppm. For HV-1, the mixed air dampers

appeared to remain in their recirculation positions (100% return air) during




occupied mode. Damper operation should be reviewed and corrections made to

ensure the dampers modulate to the commanded position. For HV-2, the mixed

air dampers are unable to modulate 100% open. The dampers appear to stop

modulating once they are approximately 75% open.



Outside Air (DCV). Various CO2 sensors were reading Unreliable in the Metasys

system and need to be recalibrated. For UV-101, the pneumatic line appears to

be disconnected from damper actuator. The dampers did not modulate when

commanded. For UV-121, the return air damper does not move and stays in full

open position. The damper and linkage appear to require adjustment.

BMS:

South Elementary School – RTU – Rooms 142 & 144

South Elementary School – UV – Classroom 103




3.9 West Elementary School


AHU’s serve A Pod and B Pod Classrooms, Library, Classrooms between the Main

Office and the Library, both Gyms and the Auditorium. UV’s serve the Main Office,

Cafeteria, Kitchen, Kindergarten, Grade 1a and Grade 5 Classrooms.

HVAC Assessment:

A total of 39 issues were identified at the West Elementary School with 8 of







AHUs

Total No.

RTUs

Total No.

UVs

Total No.

of Issues

West Elementary 10 ---- 20 39

AHU’s: The four AHU’s in the basement have 2” MERV 13 filters. The Auditorium

AHU has 2” MERV 8 filters. It should be confirmed if the Auditorium AHU can be

upgraded to MERV 13 filters. For AHU-C, the three dampers (outside air, return

air and exhaust air) do not fully open when commanded to 100%. Damper

linkage may require some adjustment. For AHU-D, the return air damper did not

appear to modulate. It remained fully open with the outside air damper

commanded to 100% open. For AHU-E, the return air damper and exhaust air

damper range of modulation appears to be limited. For the Auditorium Unit, the

mixed air dampers only opened to approximately 20% position when

commanded to the 100% position.

HV Units: For the three HV units serving the two Gymnasiums, filter types were

not observed due to the high elevations of the HV unit installations. When the




dampers positions were commanded to 100% and 0%, the actuator pistons were

observed to stroke, but the actual damper positions were not visually verified.

Unit Ventilators: Units have been provided with 1” MERV 8 filters. The majority of

filters were dirty. NV5 was informed that these filters are scheduled to be

replaced within the next week. The filters in the four unit ventilators serving the

Cafeteria do not have MERV ratings. These four units have multiple filters in

them and they do not appear to be the correct size for the units. Outside air


Outside Air (non-DCV). For a number of the unit ventilators, the dampers did not

appear to modulate, or had minimal modulation. It was noted that the linkage

for many of these dampers were not functional, corroded and impeded by debris.

The dampers and linkage are dirty.

BMS:

West Elementary School – AHU-1




West Elementary School – UV – Room D1




3.10 Shawsheen Preschool


A Dedicated Outside Air (DOA) system serves the whole building. UV’s serve the

classrooms in the West Wing.

HVAC Assessment:

A total of 4 issues were identified at the Shawsheen Preschool with all 4 of these

issues determined to be high priority. 100% of the high priority issues were

addressed and repaired prior to teachers and students returning to school.


AHUs

Total No.

RTUs

Total No.

UVs

Total No.

of Issues

Shawsheen Preschool 1 ---- 4 4

Unit Ventilators: The four unit ventilators have been provided with 1” MERV 8

filters. The dampers did not appear to be fully functional. When the dampers

were commanded to modulate, the return air damper did not change position.

The outdoor air damper could not be observed because it is located behind the

return air damper blade. The damper linkages appear to be in poor condition and

require maintenance/repair. Damper operation should be reviewed by the

facilities group at each unit.

When the unit ventilators were in occupied mode, the mixed air dampers were

being commanded to 0% open. Since the units do not have a return air CO2

sensor, the minimum mixed air damper command should be 75% open during

occupied mode.

For UV-1 serving Classroom 3/3a, the supply fan remained off when it was being

commanded to run. The fan operation should be reviewed by the facilities group.




BMS:

Shawsheen Preschool – Fresh Air Makeup Unit

Shawsheen Preschool – UV-3 – Classroom 9 & 9A

General Observations



4.0 General Observations

HVAC System Air Filters:

The schools’ HVAC systems with existing 2” filters were to be provided with new MERV 13 filters.

This includes the Rooftop Units, Air Handling Units and HV Units serving the buildings.

The schools’ HVAC systems with existing 1” filters were to be provided with new MERV 8 filters.

This includes the Unit Ventilators serving the classroom spaces.

Filter types were verified by NV5 as the system operations were reviewed. Based on the Town’s

Preventative Maintenance records, the majority of filters were changed in February and March

of 2020. The Town has noted that all filters have been replaced by the end of August 2020. As

noted by the Town, 95% of the school HVAC equipment with 2” filters have been provided with

MERV 13 filters. Any remaining filter replacements are currently due to filter orders being

backlogged at the manufacturing sites. The Town of Andover does have the required filters on

order.

Any systems that had dirty filters were noted by NV5 and the Department of Facilities

department has changed those filters prior to the start of school. The Town will also be changing

filters based upon the upcoming Preventative Maintenance schedules. The Town’s preventative

maintenance schedule has the filters being changed every three months throughout the school

year.

Demand Control Ventilation (DCV) Systems:

The schools utilize Johnson Controls Metasys for the Building Management System (BMS) for

each of the schools.

For any systems that are not programmed with DCV controls, the minimum mixed air damper

position is to be set to 75% open (75% outside air, 25% return air).

For any systems that are programmed with DCV controls, the minimum damper position is to be

set to 50% open. As the CO2 level increases from 600 ppm to 800 ppm, the damper position is

to increase from 50% to 100% (100% outside air, 0% return air).

The Department of Facilities department has noted that the CO2 sensors are calibrated

periodically utilizing a calibration kit or a calibrated sensor.

Occupancy Schedules:

Pre and post occupancy purge cycles to flush the building with clean air were implemented and

the occupancy schedules for the schools has been revised to two hours prior to the maintenance

staff arriving on site at 6:00 a.m., until two hours after the maintenance staff has left the site at

General Observations



11:00 p.m. Consequently, the HVAC systems will be operating from 4:00 a.m. until 1:00 a.m.,

and will be off from 1:00 a.m. until 4:00 a.m., Monday through Saturday. This programming has

been done in the Town’s Metasys building management system (BMS). The Town has noted

that Wednesday’s and Saturday’s will be cleaning days for the schools.

Negative Pressure Isolation Rooms:

The Town of Andover has established an isolation room in each school to house any student or

faculty that is not feeling well and has been assessed by the school nurse to remain in isolation

from the school population. Each isolation room has been equipped with a manometer on the

outside of the room to display the room’s air pressure in relation to the adjacent spaces. The

isolation rooms were targeted to have a pressure of -0.01 inches of water column (-0.01“w.c.) in

relation to the adjacent spaces. With the space being negative, this indicates that air is flowing

from the adjacent spaces into the isolation room, with the door closed. The majority of the

isolation rooms have been provided with signage to indicate restricted access to the space. The

majority of the isolation rooms have a second means of egress to allow the isolated person to

exit the space through another means of access to the exterior of the building.

Future Planned Projects



5.0 Recommendations and Next Steps

In Summary, the Department of Facilities meets and in many cases exceeds the guidelines

outlined in the ASHRAE guidance for the reopening of schools. All of the major AHUs and RTUs

were assessed and all noted deficiencies are recorded and tracked in the Departments work

order system. The Department of Facilities has indicated that all high priority items, relating to

operation, outside air damper setpoints and BMS communications, have been corrected as of

Wednesday, September 16, 2020.

Lower priority items such as filter change-outs (MERV 8 changed to MERV 13) will be addressed

once backlogged filter orders are received. CO2 sensor calibrations will be also performed as

required. The CO2 sensor corrections are lower priority as the typical outside air volume

delivered by the HVAC systems has already been increased based on the revised Metasys

programming.

Pre and post occupancy purge cycles have been incorporated for every school through the BMS

and outside air intake has been increased to provide a good supply of outside air in accordance

with ASHRAE Standard 62.1. Demand control ventilation (DVC) strategies and other control

strategies have been modified so as not to adversely impact the amount of outside air delivered

to the space.

Department of Facilities Planned Upgrades:

The Department of Facilities noted that they have started the process of cleaning the exhaust

grilles throughout the schools’ spaces. Facilities personnel also noted that they are in the

process of creating an annual preventative maintenance program for inspecting and cleaning

the exhaust systems serving the schools. This process will create better conditions for the space

airflows to be maintained as designed and will allow the exhaust equipment to operate under

the intended conditions.

The Department of Facilities noted that they have employed additional staff that are targeted to

perform HVAC system filter replacements as scheduled through the PM work order schedule.

This staff is also targeted to receive training on the Metasys controls system so that they can

functionally test the HVAC systems and review their operation on a regularly scheduled basis.

Additionally, they have created an automatically generated PM for each school to inspect and

clean every exhaust grill in every school.

The Department of Facilities noted that they have just obtained funding at the 2020 town

meeting to create a system-wide inventory of the town and schools’ mechanical systems to

create a 20 year replacement plan.

South Elementary School has begun design phase services for replacement of all new HVAC

equipment serving all spaces.

Future Planned Projects



Recommendations for Improving HVAC System Performance:

It is recommended that the facilities group review the damper operations of each of the HVAC

systems during the filter change that proceeds the start of the school year. With this, any

damper operation deficiencies can be addressed prior to the school year.

Throughout the school year, it is recommended that the facilities group reviews the Metasys

BMS system periodically, to confirm that any overrides, communication drops or any other items

can be addressed and set back to their normal operating parameters.

As a majority of the schools have Unit Ventilator systems serving the classrooms, it is

recommended that the custodial staff avoid sweeping the floors towards the bottom of the units

as this is where the return air from the space is drawn in. This would help to avoid any paper

trash or dust from being drawn in to the unit ventilators and reducing the effectiveness of the

filters. Outside air inlets should also be cleaned on a regular basis as the intakes have the

tendency to accumulate leaves, grass and other debris from the exterior of the building.

It is recommended that the HVAC systems be retro-commissioned so that their full operation

can be reviewed and any deficiencies can be addressed to keep the systems operating in the

manner they were designed to operate. Refer to the next section for additional retro-

commissioning information.

Retro-Commissioning:

Retro-commissioning is the application of the commissioning process to existing buildings.

Retro-commissioning is a process that seeks to improve how building equipment and systems

function together. Depending on the age of the building, retro-commissioning can often address

problems that have developed throughout the building's life. In all, retro-commissioning

improves a building's operations and maintenance (O&M) procedures to enhance overall

building performance, increase occupant comfort and save energy. It is recommended that a

building’s HVAC systems be retro-commissioned every three to five years. It is estimated that

retro-commissioning services would cost an estimated $25,000 to $30,000 per school.

In addition to retro-commissioning, it is recommended that a certified Testing, Adjusting and

Balancing (TAB) firm take air flow and water flow readings on the HVAC systems to evaluate if

they are operating as originally designed. The TAB firm could then make any possible

adjustments to the HVAC systems so that they are operating as close as possible to their

original design.

Public Schools HVAC Assessment

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