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BACON ACADEMY
AIR-CONDITIONING SYSTEM
ASSESSMENT/OPTION NARRATIVES
Prepared for:
Colchester Public Schools
February 26, 2025
101 Centerpoint Drive, Suite 237
Middletown, CT 06457
Phone: 860-316-2124 HFL File No. 2024-2154.01
BACON ACADEMY - COLCHESTER HIGH SCHOOL
EXISTING AIR-CONDITIONING SYSTEM ASSESSMENT
February 26, 2025
Page 1 of 8
BUILDING / GENERAL DOCUMENTATION
AIR-CONDITIONING (AC) ASSESSMENT NARRATIVES
This document consists of an AC System Assessment with recommendations for potential
upgrades to the existing AC Systems. The intent of this narrative is to describe general
concepts and possible design intent. This document is not intended to fulfill a design
development or construction document submission, nor should it be construed as an all-
encompassing scope of work.
DESIGN STANDARDS
It is anticipated, based on the preliminary design/construction schedule, the current 2022
Connecticut State Building Codes will be in effect:
The new Connecticut state codes that will be in effect, will be the:
• 2022 Connecticut State Building Code
• 2022 Connecticut State Fire Safety Code
• 2022 Connecticut State Fire Prevention Code
The following model codes are part of the 2022 Connecticut State Building Codes:
• 2021 International Building Code (IBC)
• 2021 International Existing Building Code (IEBC)
• 2021 International Energy Conservation Code (IECC)
• 2021 International Mechanical Code (IMC)
• 2021 International Plumbing Code (IPC)
• 2017 ICC A117.1 Accessible and Usable Building and Facilities
• 2021 International Fire Code (new buildings)
• 2021 NFPA 101 – Life Safety Code (existing buildings)
• 2021 NFPA 1 - Fire Code
BACKGROUND
The Bacon Academy opened in 1993 and is a 192,564 square foot comprehensive public
high school building located at 611 Norwich Avenue, Colchester, CT. Bacon Academy
provides education for grades nine through twelve in Colchester.
BACON ACADEMY - COLCHESTER HIGH SCHOOL
EXISTING AIR-CONDITIONING SYSTEM ASSESSMENT
February 26, 2025
Page 2 of 8
Air conditioning and cooling is present in most classrooms and administrative office areas.
Air conditioning and cooling has not been provided, and is desired, for additional portions
of the building, including but not limited to:
1. Technical Classrooms
2. Gymnasium and Fitness Room
3. Locker rooms
4. Kitchen areas.
In other areas of the building, original air conditioning equipment is not energy efficient, is
near or past its expected useful life, and/or must be replaced or refurbished. This
equipment includes the:
1. Cafeteria package rooftop unit
2. Outdoor air conditioning units and evaporator (DX) coils for academic wings A1,
A2, A3, and A4
3. Art room B1
4. Auditorium areas G1 and G2.
Certain existing air conditioning equipment is no longer operational because R-22
refrigerant used for equipment included as part of the original building construction is no
longer in production and available for reasonable purchase. Also, global refrigeration
manufacturers are phasing out HFC refrigerants, such as R-410A, due to their significant
global warming potential. While R-410A is a non-flammable type A1 refrigerant, most
lower global warming potential replacement refrigerants are mildly flammable, type A2L
refrigerants. Because of their flammability, the A2L refrigerants potentially require
additional safeguards built into the equipment that uses them. Coordination with local
officials will provide potential safeguards and measures to be included within the design.
Colchester's desired goals and scope for this project include:
1. Provide new AC equipment to cool the entire building.
2. Minimize safeguard scope, that may be required for use of the latest mildly
flammable A2L refrigerants by locating the majority of refrigerant outside the
buildings or within mechanical spaces.
3. Utilize an already awarded Indoor Air Quality (IAQ) grant, to maximize upgrades
to existing AC equipment and/or provide AC in desired locations, which currently
does not have air-conditioning.
BACON ACADEMY - COLCHESTER HIGH SCHOOL
EXISTING AIR-CONDITIONING SYSTEM ASSESSMENT
February 26, 2025
Page 3 of 8
MECHANICAL
MECHANICAL DESIGN NARRATIVE
This document consists of an AC Assessment with recommendations for potential upgrades
to the existing AC Systems. The intent of this narrative is to describe general engineering
system concepts, design intent, and approximate system capacities. This document is not
intended to fulfill a design development or construction document submission, nor should it
be construed as an all-encompassing scope of work.
DESIGN STANDARDS
The mechanical work, material, and equipment shall comply with the following codes:
IBC 2021 International Building Code
IMC 2021 International Mechanical Code
IECC 2021 International Energy Conservation Code
NFPA National Fire Protection Association
ASHRAE American Society of Heating, Refrigerating, and Air-Conditioning
Engineers
OSHA Occupational Safety and Health Administration
UL Underwriters Laboratories
Applicable County, State and Local Codes
Rules of State Fire Marshall
MECHANICAL DESCRIPTION OF EXISTING SYSTEMS
H.F. Lenz conducted site investigations of the building on January 13, 2025. Here is a
summary of the key findings:
1. The building uses refrigerant (DX) cooling that uses either R-22 or R-410A
refrigerants. Both of these refrigerants have or will become obsolete due to their
significant ozone depletion and global warming potentials. Large indoor Air
Handling Units (AHUs) contain cooling coils that are connected to refrigerant
condensing units on the roof or ground. In general, the indoor AHUs are in fair to
good condition, but the outdoor condensing units, which provides that actual ability
to cool spaces, are at or beyond their useful life.
BACON ACADEMY - COLCHESTER HIGH SCHOOL
EXISTING AIR-CONDITIONING SYSTEM ASSESSMENT
February 26, 2025
Page 4 of 8
2. Although the heating system was not in our scope, we reviewed the system at the
Air Handling Unit level, to fully understand the intended design strategy utilized by
the existing Air Handling Units. The existing fuel oil boilers create Heating Hot
Water (HHW) at 180°F and the HHW pumping system delivers the heat to AHUs
and other heating devices throughout the building. At the AHUs, the 100% water
from the boilers enters a water-glycol mix/water heat exchanger, and the glycol
loop delivers HHW glycol mix to the AHU heating coils. A glycol-water mix
minimizes the possibility of coil freeze damage during winter weather.
BACON ACADEMY - COLCHESTER HIGH SCHOOL
EXISTING AIR-CONDITIONING SYSTEM ASSESSMENT
February 26, 2025
Page 5 of 8
3. The woodworking shop contains two indoor AHUs that provide 100% Outdoor Air
(OA) to compensate for the woodworking equipment exhaust system. These AHUs
have return grilles that allow them to heat the space when it is unoccupied. An
isolation damper should close when the space is occupied and the AHU brings in
100% OA. The return duct's isolation damper is either broken or not installed.
Return duct
4. Typical indoor Classroom AHU, which contains both a heating coil and a cooling
coil, which utilizes outdated refrigerant.
BACON ACADEMY - COLCHESTER HIGH SCHOOL
EXISTING AIR-CONDITIONING SYSTEM ASSESSMENT
February 26, 2025
Page 6 of 8
MECHANICAL SYSTEM UPGRADE OPTIONS
Based on the District having a target budget goal, H.F. Lenz proposes the following
mechanical upgrade options in a "Good, Better, Best" format for the Bacon Academy. The
budgets are a Rough Order Magnitude (ROM) at this conceptual phase and will be refined
through the design process. Bid alternates will be utilized within final design documents in
order to provide the district some flexibility based on contractor bids, which will be heavily
affect by the material and labor market at the time of bidding.
REPLACE EXISTING DX COOLING IN-KIND - $ 1.5 Million
Scope of Work:
A. For each modular indoor AHU, replace the existing refrigerant cooling coil, and
associated outdoor condensing unit, with new equipment.
1. Academic wings AHUs A1, A2, A3, and A4
2. Auditorium AHUs G1, G2, and G3.
3. Gymnasium AHUs D1, and D2. Add cooling.
4. Art room AHU B1. (Likely a Bid Alternate)
B. Replace cafeteria RTU. (Likely a Bid Alternate)
Pros
1. This option is the most cost-effective way of upgrading the existing cooling
systems based on currently installed mechanical cooling methods.
2. Most cost-effective options allow for the most square footage of building
space to be upgraded, providing the most thermal comfort possible with
available budget dollars.
3. Due to more efficient equipment, electric scope of work is minimized, thus
providing more spending dollars for mechanical cooling.
4. Existing cooling only condensing units, upgraded in the philosophy, to heat
pumps, would provide a by-product of additional heating, thus potentially
minimizing the heating load placed on the boiler system.
Cons
1. A2L refrigerants, if used, may require inclusion of safeguards, based on
coordination with authorities having jurisdiction, which would be
completed during the design phase.
BACON ACADEMY - COLCHESTER HIGH SCHOOL
EXISTING AIR-CONDITIONING SYSTEM ASSESSMENT
February 26, 2025
Page 7 of 8
REPLACE EXISTING DX COOLING WITH AIR-COOLED CHILLERS - $ 1.5 Million
Scope of Work:
A. For each modular indoor AHU, replace the existing refrigerant cooling coil, and
associated outdoor condensing unit, with new chilled water equipment.
1. Academic wings AHUs A1, A2, A3, and A4
2. Gymnasium AHUs D1, and D2. Add cooling.
B. Replace cafeteria RTU in-kind. (Likely Bid Alternate)
Pros
1. This option eliminates the use of refrigerants in their entirety, which often
times is district specific request, or requirement based on 'green' strategies
deployed.
2. This option eliminates the use of A2L refrigerants inside the building under
normal operation. A2L refrigerants are new to the market, and each
manufacturer is selecting their own specific refrigerant, with unknown,
new challenges to be worked out at the beginning of their refrigerant life-
cycle.
Cons
1. Significantly higher cost than in-kind replacements.
2. Square footage upgrades minimized, thus minimizing the spending power
of the awarded grant.
3. This option assumes existing roof supports can be reused to support air-
cooled chillers with minimal improvements. Project costs may increase
through the design phase, if it is determined that supplemental steel is
required to support the air-cooled chillers.
REPLACE EXISTING DX COOLING WITH AIR-COOLED CHILLERS AND ENERGY
RECOVERY VENTILATORS - $ 1.5 Million
Scope of Work:
A. Replace cafeteria RTU in-kind.
B. For each modular indoor AHU, replace the existing refrigerant cooling coil, and
associated outdoor condensing unit, with new chilled water equipment.
1. Academic wings AHUs A1, A2, A3, and A4
C. For each modular indoor AHU, install a new Energy Recovery Ventilator that
recovers heating and cooling from building exhaust air to pre-condition outdoor air.
Install on roof, on indoors through OA intake louver. Add ductwork from AHU to
ERV.
BACON ACADEMY - COLCHESTER HIGH SCHOOL
EXISTING AIR-CONDITIONING SYSTEM ASSESSMENT
February 26, 2025
Page 8 of 8
Pros
1. This option eliminates the use of refrigerants in their entirety, which often
times is district specific request, or requirement based on 'green' strategies
deployed.
2. This option eliminates the use of A2L refrigerants inside the building under
normal operation. A2L refrigerants are new to the market, and each
manufacturer is selecting their own specific refrigerant, with unknown,
new challenges to be worked out at the beginning of their refrigerant life-
cycle.
3. Adding ERVs can save significant energy, especially in heating season.
4. When ERVs are added, the current energy conservation code requires the
cooling and heating equipment be downsized to account for the
preconditioning by the ERVs. This downsizing will lead to first cost
savings that can be applied to the ERV first costs.
Cons
1. Significantly higher cost than in-kind replacements, or air-cooled chillers.
2. Even further reduction of square footage upgrades, thus minimizing the
spending power of the awarded grant.
3. This option assumes existing roof supports can be reused to support air-
cooled chillers with minimal improvements. Project costs may increase
through the design phase, if it is determined that supplemental steel is
required to support the air-cooled chillers.
JOB NAME: Bacon Academy IAQ
CONSTRUCTION COST ESTIMATE
JOB #: 2024-2154.01
ITEM: Bacon Academy - Colchester High School DATE: 2/26/2025
Option A: In-Kind Replacement Dx ESTIMATOR: HFL
SHEET 1 OF 3
MATERIAL COST LABOR COST LINE
ITEM DESCRIPTION QTY UNIT PER UNIT TOTAL PER UNIT TOTAL TOTAL
DEMOLITION
1 Remove existing Cafeteria RTU 1 EA $ 100.00 $ 100 $ 1,600.00 $ 1,600 $ 1,700
2 Remove existing Condensing Units 8 EA $ 100.00 $ 800 $ 3,200.00 $ 25,600 $ 26,400
3 Remove existing Refrigerant & its Piping 4 EA $ 500.00 $ 2,000 $ 1,000.00 $ 4,000 $ 6,000
4 Remove CU and RTU Electrical 9 EA $ 150.00 $ 1,350 $ 750.00 $ 6,750 $ 8,100
5 Remove existing CC in AHU 8 EA $ 100.00 $ 800 $ 1,200.00 $ 9,600 $ 10,400
6
7 NEW WORK
8 Cafeteria RTU 1 EA $ 42,000.00 $ 42,000 $ 3,000.00 $ 3,000 $ 45,000
9 CUs 10 EA $ 26,500.00 $ 265,000 $ 3,000.00 $ 30,000 $ 295,000
10 Gym AHUs 1 EA $ 120,000.00 $ 120,000 $ 20,000.00 $ 20,000 $ 140,000
11 CU Refrig Piping/Supports/Insulation 2,400 LF $ 18.05 $ 43,315 $ 16.68 $ 40,032 $ 83,347
12 Ductwork repair & replacement 11 EA $ 2,500.00 $ 27,500 $ 2,500.00 $ 27,500 $ 55,000
13 Controls 108 PTS $ 1,000.00 $ 108,000 $ 500.00 $ 54,000 $ 162,000
14 Elec Power - Conduit, wire, disconnects 10 EA $ 5,000.00 $ 50,000 $ 5,000.00 $ 50,000 $ 100,000
15 Gas detection equipment - in AHUs/RTU 11 EA $ 5,000.00 $ 55,000 $ 2,000.00 $ 22,000 $ 77,000
16 Setup/Cx/TAB 11 EA $ 250.00 $ 2,750 $ 1,200.00 $ 13,200 $ 15,950
17 Misc painting/cutting/patching 10 EA $ 100.00 $ 1,000 $ 1,000.00 $ 10,000 $ 11,000
18 $ - $ - $ - $ - $ -
19 $ - $ - $ - $ - $ -
20 $ - $ - $ - $ - $ -
21 $ - $ - $ - $ - $ -
22 $ - $ - $ - $ - $ -
23 $ - $ - $ - $ - $ -
24 $ - $ - $ - $ - $ -
25 $ - $ - $ - $ - $ -
26 $ - $ - $ - $ - $ -
27 $ - $ - $ - $ - $ -
28 $ - $ - $ - $ - $ -
29 $ - $ - $ - $ - $ -
30 $ - $ - $ - $ - $ -
31 $ - $ - $ - $ - $ -
32 Site Mobilization 1 LOT $ - $ - $ 12,000.00 $ 12,000 $ 12,000
Subtotal $ 719,615 $ 329,282 $ 1,048,897
General Conditions (6%) $ 62,934
Overhead and Profit (10%) $ 111,183
Insurance and Bonds (5%) $ 61,151
Bid Contingency (10%) $ 128,416
Escalation (to Mid-Point 5/2025 - 2%) $ 28,252
Grand Total $ 1,440,833
JOB NAME: Bacon Academy IAQ
CONSTRUCTION COST ESTIMATE
JOB #: 2024-2154.01
ITEM:
Bacon Academy - Colchester High School DATE: 2/26/2025
Option B: Air Cooled Chillers ESTIMATOR: HFL
SHEET 2 OF 3
MATERIAL COST LABOR COST LINE
ITEM DESCRIPTION QTY UNIT PER UNIT TOTAL PER UNIT TOTAL TOTAL
DEMOLITION
1 Remove existing Cafeteria RTU EA $ 100.00 $ - $ 1,600.00 $ - $ -
2 Remove existing Condensing Units 6 EA $ 100.00 $ 600 $ 3,200.00 $ 19,200 $ 19,800
3 Remove existing Refrigerant & its Piping 4 EA $ 500.00 $ 2,000 $ 1,000.00 $ 4,000 $ 6,000
4 Remove CU and RTU Electrical 6 EA $ 150.00 $ 900 $ 750.00 $ 4,500 $ 5,400
5 Remove existing CC in AHU 6 EA $ 100.00 $ 600 $ 1,200.00 $ 7,200 $ 7,800
6
7 NEW WORK
8 Cafeteria RTU EA $ 35,000.00 $ - $ 3,000.00 $ - $ -
9 ACCs - (1) 200 tons A3,A4, A1,A2; (2) 45 ton D1, D2
1 EA $ 240,900.00 $ 240,900 $ 36,000.00 $ 36,000 $ 276,900
10 AHU Cooling Coils 6 EA $ 7.00 $ 42 $ 15,000.00 $ 90,000 $ 90,042
11 CHW Piping/Supports/Insulation 1,200 LF $ 101.00 $ 121,200 $ 70.60 $ 84,720 $ 205,920
12 CHW Pumps & Accessories 4 EA $ 20,000.00 $ 80,000 $ 12,500.00 $ 50,000 $ 130,000
13 Ductwork repair, replacement 6 EA $ 2,500.00 $ 15,000 $ 2,500.00 $ 15,000 $ 30,000
14 Controls 72 PTS $ 1,000.00 $ 72,000 $ 500.00 $ 36,000 $ 108,000
15 Elec Power - Conduit, wire, breakers, disconnects 3 EA $ 10,000.00 $ 30,000 $ 5,000.00 $ 15,000 $ 45,000
16 Setup/Cx/TAB 3 EA $ 500.00 $ 1,500 $ 2,200.00 $ 6,600 $ 8,100
17 Structural Support Upgrades 4 EA $ 15,000.00 $ 60,000 $ 8,000.00 $ 32,000 $ 92,000
18 Misc painting/cutting/patching 4 EA $ 100.00 $ 400 $ 1,000.00 $ 4,000 $ 4,400
19 $ - $ - $ - $ - $ -
20 $ - $ - $ - $ - $ -
21 $ - $ - $ - $ - $ -
22 $ - $ - $ - $ - $ -
23 $ - $ - $ - $ - $ -
24 $ - $ - $ - $ - $ -
25 $ - $ - $ - $ - $ -
26 $ - $ - $ - $ - $ -
27 $ - $ - $ - $ - $ -
28 $ - $ - $ - $ - $ -
29 $ - $ - $ - $ - $ -
30 $ - $ - $ - $ - $ -
31 $ - $ - $ - $ - $ -
32 Site Mobilization 1 LOT $ - $ - $ 12,000.00 $ 12,000 $ 12,000
Subtotal $ 625,142 $ 416,220 $ 1,041,362
General Conditions (6%) $ 62,482
Overhead and Profit (10%) $ 110,384
Insurance and Bonds (5%) $ 60,711
Bid Contingency (10%) $ 127,494
Escalation (to Mid-Point 5/2025 - 2%) $ 28,049
Grand Total $ 1,430,482
JOB NAME: Bacon Academy IAQ
CONSTRUCTION COST ESTIMATE
JOB #: 2024-2154.01
ITEM: Bacon Academy - Colchester High School DATE: 2/26/2025
Option C: Energy Recovery Ventilators ESTIMATOR: HFL
SHEET 3 OF 3
MATERIAL COST LABOR COST LINE
ITEM DESCRIPTION QTY UNIT PER UNIT TOTAL PER UNIT TOTAL TOTAL
DEMOLITION
1 Remove existing Cafeteria RTU 1 EA $ 100.00 $ 100 $ 1,600.00 $ 1,600 $ 1,700
2 Remove existing Condensing Units 4 EA $ 100.00 $ 400 $ 3,200.00 $ 12,800 $ 13,200
3 Remove existing Refrigerant & its Piping 4 EA $ 500.00 $ 2,000 $ 1,000.00 $ 4,000 $ 6,000
4 Remove CU and RTU Electrical 4 EA $ 150.00 $ 600 $ 750.00 $ 3,000 $ 3,600
5 Remove existing CC in AHU 4 EA $ 100.00 $ 400 $ 1,200.00 $ 4,800 $ 5,200
6
7 NEW WORK
8 Cafeteria RTU 1 EA $ 35,000.00 $ 35,000 $ 3,000.00 $ 3,000 $ 38,000
9 ACCs - (1) 200 tons A3,A4, A1,A2
1 EA $ 163,500.00 $ 163,500 $ 15,000.00 $ 15,000 $ 178,500
10 AHU Cooling Coils 4 EA $ 7,000.00 $ 28,000 $ 15,000.00 $ 60,000 $ 88,000
11 ERVs - 5000 CFM 4 EA $ 15,000.00 $ 60,000 $ 15,000.00 $ 60,000 $ 120,000
12 CHW Piping/Supports/Insulation 800 LF $ 85.85 $ 68,680 $ 63.54 $ 50,832 $ 119,512
13 CHW Pumps & Accessories 2 EA $ 20,000.00 $ 40,000 $ 12,500.00 $ 25,000 $ 65,000
14 Ductwork repair & replacement, add for ERV 4 EA $ 15,000.00 $ 60,000 $ 10,000.00 $ 40,000 $ 100,000
15 Controls 48 PTS $ 1,000.00 $ 48,000 $ 500.00 $ 24,000 $ 72,000
16 Elec Power - Conduit, wire, breakers, disconnects 1 EA $ 90,000.00 $ 90,000 $ 36,000.00 $ 36,000 $ 126,000
17 Setup/Cx/TAB 5 EA $ 500.00 $ 2,500 $ 2,200.00 $ 11,000 $ 13,500
18 Structural Support Upgrades 2 EA $ 15,000.00 $ 30,000 $ 6,000.00 $ 12,000 $ 42,000
19 ERV Supports - roof curbs or Conc pads 4 EA $ 3,000.00 $ 12,000 $ 2,000.00 $ 12,000 $ 24,000
20 Misc painting/cutting/patching 4 EA $ 100.00 $ 400 $ 1,000.00 $ 4,000 $ 4,400
21 $ - $ - $ - $ - $ -
22 $ - $ - $ - $ - $ -
23 $ - $ - $ - $ - $ -
24 $ - $ - $ - $ - $ -
25 $ - $ - $ - $ - $ -
26 $ - $ - $ - $ - $ -
27 $ - $ - $ - $ - $ -
28 $ - $ - $ - $ - $ -
29 $ - $ - $ - $ - $ -
30 $ - $ - $ - $ - $ -
31 $ - $ - $ - $ - $ -
32 Site Mobilization 1 LOT $ - $ - $ 12,000.00 $ 12,000 $ 12,000
Subtotal $ 641,580 $ 391,032 $ 1,032,612
General Conditions (6%) $ 61,957
Overhead and Profit (10%) $ 109,457
Insurance and Bonds (5%) $ 60,201
Bid Contingency (10%) $ 126,423
Escalation (to Mid-Point 5/2025 - 2%) $ 27,813
Grand Total $ 1,418,463