PROJECT – #5921532 D-B Replace Air Handler Units B873, PSNS, Bremerton, WA
Scope of Work: Replace existing 12 AHUs with new 100% OA rooftop units with inlet air dampers, filters, steam coil, roof curbs, and supply fans adding Variable Frequency Drivers with controllers in 4 separate phases.
Note: AHUs are currently directly connected to various Scrubbers (total of 7 Ea). For best case sequencing of removing each Scrubber offline while keeping production processes uninterrupted, AHU condition & production demands were considered. The following Phases were developed with these in mind so any PHASE can be performed in any order. Performing work on any AHU outside of its Phase is not recommended
Note: MU – Mechanical Unit, OA – Outdoor Air, S – Supply System
Phase 1: MU S-2, S-5, S-10 (Supports Scrubbers 8, 9, & 10)
Phase 2: MU S-1, S-3, S-9, S-11 (Supports Scrubber 3)
Phase 3: MU S-4, S-6, S-12 (Supports Scrubbers 5 & 6)
Phase 4: MU S-7, S-8 (Supports Scrubber 7)
-Currently, AHUs are controlled by the pressure sensors located throughout the building (4 locations or 4 zones) to balance the airflow between AHUs and Scrubbers to maintain the building production requirements. This control method shall be retained and reconnected to the new AHUs with new programming and additional components.
-Install Alarm or Notification (or Warning) light to notify occupants when the building pressure is out of pre-set range.
-Wash and clean interior ducting of the existing roof plenum, and paint exterior duct; if existing roof plenum is in bad shape, replace ducting from AHU to 54/27 (2 each) down ducting.
-A new 60 mil PVC material should be temperature sealed to the existing PVC roofing material (where exposed/disturbed during the AHUs replacement works), adding flashing where required, and structurally fortifying the sleeper foundations where necessary.
-Relocate the steam modulating valve, MV-1 thru -12 from underneath of the roof to the top of the roof for better access and facilitate the maintenance work. Weather type enclosures shall be added for housing the steam modulating valves. Valve should be Spring Opening type in case of power loss. This will force the valves open and prevent freeze damage to the piping and steam coils.
- Remove 2 Chillers (labeled with 09DE044600, Carrier), and abandoned piping, components, and foundations no longer operating/using.
CLIN 0001: Design & Construction Replacing AHUs 1-6
CLIN 0002 – Option 01: Replacing AHUs 7-12
Magnitude of the Construction Contract: $1M-$5M
Bids/Proposals Due: July 14 – 10:00am