Boston-A-3.pdf
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- Solicitation number
- BD-27-1030-CPO1-CPO1-131243
- Issued by
- Suffolk County, Massachusetts
About this file
This is Addendum No. 3 to the contract documents for the Boston Cooling Tower Replacements at Haymarket Center project, issued by the Massachusetts Department of Transportation on July 30, 2026. The addendum transmits revisions to the contract documents and supersedes previously filed sub-bid information with updated Final Filed Sub-Bid Results posted on COMMBUYS. The revision includes an updated Plan Sheet M-000 containing HVAC legend, notes, details, and schedules. Sub-bids were opened and read on July 27, 2026 at 2:00 p.m., with general bids scheduled to be opened and read on August 5, 2026 at 2:00 p.m. Prospective bidders are required to acknowledge Addendum No. 3 in their proposal files before submitting their bids. The project scope includes the installation of two new stainless steel cooling towers (Model NC8401NAN1 with 118 CFM, 60 MBH cooling capacity), a new ceiling-mounted air handling unit (BCHE054 with 1,800 CFM capacity), and a new exhaust fan (AX-36-25-0420-VG-4 with 1,560 CFM capacity) for the generator room. All existing HVAC systems, ductwork, piping, and controls shall remain unless otherwise noted, with the contractor responsible for reconnecting piping and controls and providing system startup and commissioning.
The addendum includes detailed technical specifications and design details for equipment installation, including requirements for vibration isolation, internal heater provisions on fan motors, stainless steel construction, water inlet configurations, equalizing line connections, vibration switches, and electric water level controls on cooling towers. The contractor is required to coordinate exact equipment locations with existing field conditions per manufacturer instructions while maintaining recommended clearances, with any discrepancies to be brought to the architect/engineer for clarification. New chilled water supply and return piping (3/4" PVC) must be provided to connect to existing piping, with air handling unit condensate drain routed to the floor drain. The drawings are diagrammatic and indicate approximate equipment locations; the contractor must verify existing conditions in the field and coordinate with the supporting equipment requirements specified by the cooling tower manufacturer. All work shall comply with the sequence of operation specified for the exhaust fan controls and intake damper interlock system.
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Text version
July 30, 2026
Proposal No. 616454-134457
ADDENDUM NO. 3
To Prospective Bidders and Others on:
BOSTON
COOLING TOWER REPLACEMENTS AT HAYMARKET CENER
SUB-BIDS OPENED AND READ: JULY 27, 2026 @ 2:00 P.M.
GENERAL BIDS TO BE OPENED AND READ: AUGUST 5, 2026 @ 2:00 P.M.
Transmitting changes to the Contract Documents as follows:
FILED SUB-BID RESULTS AND RESTRICTIONS
The filed sub-bid information for the Project in Addendum No. 2 is superseded by the filed sub-bid information for the Project in the document entitled Final Filed Sub-Bid Results that is posted on
COMMBUYS.”
DRAWING REVISIONS
Revised Plan Sheet M-000
Please take note of the above and acknowledge Addendum No. 3 in your Proposal file before submitting your bid.
HVAC LEGEND
CT
AHU
EF
COOLING TOWER
AIR HANDLING UNIT
EXHUAST FAN
CHWS&R CHILLED WATER SUPPLY AND RETURN
AFF ABOVE FINISHED FLOOR
HP HORSE POWER
DN DOWN
HVAC HEATING, VENTILATING & AIR CONDITIONING
DOV DRAIN-OFF VALVE
CFM CUBIC FEET PER MINUTE
EA EXHAUST AIR
OA OUTDOOR AIR
SA SUPPLY AIR
RA RETURN AIR
EC ELECTRICAL CONTRACTOR
GC GENERAL CONTRACTOR
PC PLUMBING CONTRACTOR
BFP BACKFLOW PREVENTER
CD CONDENSATE DRAIN
ESP EXTERNAL STATIC PRESSURE
TYP. TYPICAL
ROUND AIR DUCT UP
ROUND AIR DUCT DOWN
SUPPLY AIR DUCT UP
SUPPLY AIR DUCT DOWN
RETURN/EXHAUST AIR DUCT UP
RETURN/EXHAUST AIR DUCT DOWN
MOTORIZED DAMPER
MD
CONDENSATE WATER SUPPLY
CONDENSATE WATER RETURN
CONDENSATE DRAIN
CHILLED WATER SUPPLY
CHILLED WATER RETURN
MAKE UP WATER PIPE
THERMOSTAT-ELECTRICT
MW
CHWR
CHWS
CD
CNR
CNS PIPE UP
PIPE DOWN
PIPE TEE DROP
PIPE STUB UP W/FLOW ARROW
PIPE ANCHOR
PIPE GUIDE
GATE VALVE
STRAINER
CONTROL VALVE
DRAIN-OFF VALVE W/UNION
DOV
BUTTERFLY VALVE
GLOBE VALVE
BALL VALVE
FLEXIBLE PIPE
THERMOMETER
PRESSURE GAUGE
AUTOMATIC AIR VENT
BACKDRAFT DAMPER
BD
CNS&R CONDENSATE WATER SUPPLY AND RETURN
CONNECT NEW TO EXISTING
1.
2.
3.
4.
ALL EXISTING HVAC SYSTEMS, DUCTWORK, DIFFUSERS, REGISTERS & GRILLES,
PIPING, CONTROLS ETC. SERVING THE BUILDING SHALL REMAIN UNLESS
OTHERWISE NOTED.
CONTRACTOR SHALL RECONNECT PIPING AND CONTROLS TO THE REINSTALLED
EQUIPMENT AND PROVIDE START-UP FOR ALL EQUIPMENT AND CONFIRM
RECONNECTED EQUIPMENT WORKS WITH EXISTING CONTROL SEQUENCE.
CONTRACTOR SHALL LOCATE ALL NEW EQUIPMENT INCLUDING BUT NOT LIMITED TO
THE COOLING TOWERS, FANCOIL UNITS AND EXHAUST FAN ETC. PER MANUFACTURER'S
INSTRUCTIONS MAINTAINING RECOMMENDED CLEARANCES.
CONTRACTOR SHALL COORDINATE THE EXACT LOCATIONS OF ALL EQUIPMENT,
DUCTWORK, PIPING AND ASSOCIATED ACCESSORIES WITH EXISTING
CONDITIONS IN THE FIELD. DRAWINGS ARE DIAGRAMMATIC AND INDICATE
APPROXIMATE LOCATIONS OF THE APPARATUS. ANY DISCREPANCIES IN THE
FIELD SHALL BE BROUGHT TO THE ATTENTION OF THE ARCHITECT/ENGINEER
FOR CLARIFICATION.
GENERAL NOTES
1.
2.
KEYED NOTES:
NEW AHU SHALL BE CEILING MOUNTED. PROVIDE NEW CHWS&R PIPING TO CONNECT TO EXISTING PIPING AS SHOWN.
PROVIDE OFFSETS AND FITTINGS AS REQUIRED FOR CONNECTION. ROUTE AHU CD PIPING TO FLOOR DRAIN.
MOUNT COOLING TOWER ON THE EXISTING STEEL DUNNAGE WITH NEW VIBRATION ISOLATION. THE EXISTING GALVANIZED STEEL FRAME THAT IS ABOVE THE VIBRATION ISOLATORS SHALL REMAIN AND BE REUSED. CONTRACTOR TO COORDINATE SUPPORTING EQUIPMENT IN ACCORDANCE WITH COOLING TOWER MANUFACTURERS REQUIREMENTS(TYP.2).
MODEL CFM O.A.
SUPPLY FAN
HP ESP MBH
COOLING
V PH HZ
ELECTRICAL
LBS
WEIGHT
REMARKS
NO.
ITEM
AHU-1 BCHE054 1800 0 1.0 - 54 115 1 60 130 -
BASED ON TRANE
AIR HANDLING UNIT SCHEDULE
SERVICE
MECHANICAL ROOM
BASED ON MARLEY STRUCTURE AND CASING SHALL BE SS301L STAINLESS STEEL.
PROVIDE INTERNAL HEATERS ON ALL FAN MOTORS TO PREVENT INTERNAL CONDENSATION.
PROVIDE GEARBOX WITH 5 YEAR OIL CHANGE INTERVALS.
2 3
HZ
REMARKS
WB (°F)
ELECTRICAL
CFM
EWT (°F)
V PH
LWT (°F)GPMMODELNO.
ITEM FAN MOTORS
HP
EAT
CT-1&2 NC8401NAN1 95 85 78 60118 10 460 3 60
COOLING TOWER SCHEDULE
(FT)
PD
10.43
PROVIDE SINGLE WATER INLET ON ALL TOWERS.
PROVIDE EQUALIZING LINE CONNECTIONS BETWEEN CELLS.
PROVIDE VIBRATION SWITCH ON ALL TOWERS.
PROVIDE ELECTRIC WATER LEVEL CONTROL ON ALL TOWERS.7
4 5 6 7
(LBS)
WEIGHT
8,500
(KW)
BASIN HEATER
AX-36-25-0420-VG-4 IN LINE 19 115/1/60 CONTROLLED BY THERMOSTATGENERATOR ROOMEF-1 1/4900 1560.375
WEIGHT
(LBS) V/PH/HZ
BASED ON GREENHECK
SERVICE
EXHAUST FAN SCHEDULE
ITEM
NO.
MODEL TYPE ESP.
IN.
CFM HP RPM REMARKS
THREADED
SUSPENSION
RODS AS
REQUIRED(TYP.)
VIBRATION
ISOLATOR(TYP.)
STEEL CHANNEL SUPPORT
BY HVAC CONTRACTOR
(TYP.)
EXHAUST AIR DUCT
ROOF SUPPORT
STRUCTURE
FLEXIBLE
CONN.(TYP.)
INLINE FAN
EXHAUST AIR DUCT
NO SCALE
INLINE EXHAUST FAN DETAIL
BD
M
12" DEEP PLENUM
FULL SIZE OF
LOUVER
EXISTING HORIZONTAL
SUPPORT
BEAMS ±42" ON
CENTER
EXISTING METAL PANEL.
PITCH DOWN
TO LOUVER
NOTES:
FURNISH AND INSTALL AN INTAKE AIR DUCT
AS HEREINAFTER SPECIFIED. CUTTING AND
PATCHING SHALL BE BY THIS
CONTRACTOR. LOUVER IS EXISTING.
1.
2. SEQUENCE OF OPERATION: THE EXHAUST FAN
CONTROLS SHALL BE WIRED TO INTERLOCK
WITH THE CONTROL DAMPER LOCATED ON THE
INTAKE LOUVER. THE DAMPER SHALL OPEN AND
THIS WILL ALLOW THE EXHAUST FAN TO
OPERATE ON ACTIVATION OF THE
PROVING SWITCH. THE PROVING SWITCH WILL
DETERMINE IF THE DAMPER IS FULLY OPEN.
SOLDER WATER
TIGHT ALL JOINTS
MOTORIZED DAMPER
EXISTING LOUVER
NO SCALE
INTAKE DUCT INSTALLATION DETAIL
AHU NEW AIR
HANDLING
UNIT
NEW CHILLED
WATER
PIPING
3/4" PVC CONDENSATE
DRAIN TO FLOOR DRAIN
SUPPLY AIRRETURN AIR
NEW VIBRATION
ISOLATOR (TYP.)
NEW THREADED SUSPENSION
RODS AS REQUIRED (TYP.)
NEW COOLING COIL
ROOF SUPPORT
STRUCTURE
NO SCALE
AIR HANDLING SYSTEM - DETAIL
2 POSITION
CONTROL VALVE
BALL VALVE
STRAINER WITH DRAIN VALVE
1/2" MESH GALV. SCREEN1/2" MESH GALV. SCREEN
NEW 1" DRAIN VALVE
EXISTING CHWR
NO SCALE
AHU-1 CHWS&R CONNECTION DETAIL
NEW TEE
TO AHU-1
TO CHILLER
EXISTING CHWS
NEW TEE
TO AHU-1
TO CHILLER
NEW 1" CHWR NEW 1" CHWS
Professional Stamp Professional Stamp
Project Name:
MassDOT Project Number: 616454-134457
Project Location:
Project Architect
Drawn By:
Checked By:
AA Project No.:
Scale:
Original Issue Date
Revisions
Plan Name:
Drawing Number:
Project Consultant
STATE FEDERAL AID PROJECT NO. SHEET
NO.
TOTAL
SHEETS
PROJECT FILE NO.
Ten Park Plaza Suite 4160
Boston, MA 02116 857-368-4636 www.mass.gov/massdot
BOSTON
136 BLACKSTONE STREET
219 Concord Avenue Cambridge MA 02138 Tel. 617-441-8500
MA -
616454-134457
As indicated
HVAC LEGEND, NOTES,
DETAILS & SCHEDULES
M000
15 JUNE, 2026 - BID SET
COOLING TOWER
REPLACEMENT AT
HAYMARKET CENTER
136 BLACKSTONE STREET
BOSTON, MA 02109
YC
MHV
0856.35
HVAC LEGEND, NOTES, DETAILS & SCHEDULES
No. Description Date 1 Addendum #3 2026-07-30
| ADDENDUM NO. 3 |
| BOSTON |
| SUB-BIDS OPENED AND READ: JULY 27, 2026 @ 2:00 P.M. |
| GENERAL BIDS TO BE OPENED AND READ: AUGUST 5, 2026 @ 2:00 P.M. |
| DRAWING REVISIONS |
| Revised Plan Sheet M-000 |
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