Attachment 12 - Addendum 1 Phasing Plan (Dated 2 Sep 2020).pdf

ADDENDUM 1

MAHG071039

BLDG 4331 REPAIR HVAC TRAINING HALL

Phasing Plan 2 SEP 2020

1. General: This building will be occupied and services maintained during work. Contractor shall provide plastic dust barriers to segregate hallways from north south main hallways. Hallways serviced by the penthouse air handlers are stacked with one on first and one on second. As the penthouse work requires the demolition of air handlers to install new then the contractor will be offered one vertically stacked set of hallways at a time. Seal off against dust intrusion into rest of building. The first phase will be the installation of the hot water system, phase 2 will install parallel chill water system on roof, phase 3 will work the hallways (stacked) and phase 4 will work the physical plant. As the building cannot be vacated, the contractor will closely coordinate with owner and will be offered a stacked hallway section. That section will be completed with systems running and ready for occupancy to include new ductwork, new air handlers, controls, new ceilings and lights, new doors, and cleanup. The owner will remove computers and electronic, the contractor will move furniture around and use plastic drapes for protection. Lay down areas will be provided for dumpster, crane setup, and material loading.

2. Phase 1: Coordinate work with owner – remove ceilings in north south hallways for mains, install hot water piping down halls, use a ball valve at each set of runouts into classrooms, install valves in hallway for connections to VAV hot water system once a hallway is selected for rework.

Install new boilers, pumps, gas piping, make up system, expansion tank, controls, electrical work, and insulation. System checkout and startup will require having a hallway complete but system will be pressure tested. Reinstall ceilings and lights in hallways and perform cleanup daily to manage mess.

3. Phase 2: Coordinate any utility shutdown with owner as a crossover will be required to activate existing chill water and new chill water piping in parallel. Shut down house pump in mechanical room close all valves, cut in new tee after 12” ell on roof for supply and return, install butterfly valve with flange on each tee leg. The straight flow through will service existing system. Make existing system tight for continued use. Extend with ell from side leg of tee new 8” across roof with tees for new work to service penthouses. New piping for penthouse runouts shall use new pipe stand similar to existing with roofing pad below. Using existing pipe supports install heavy galvanized cross piece on existing stands for piping extending across roof to west side and extend new piping above existing. At each penthouse runout use isolation valves, rise up wall, enter penthouse high (verify inside for obstruction and locate to avoid such), and extend to new air handlers. The system will be pressure tested and when found leak free the piping will be insulated with 1” foam glass and aluminum jacket. As each penthouse is worked, the new air handlers will be serviced by new system until all penthouses are complete. Once all penthouses are on the new system then the existing system will be demolished back to the tees with valve and a blind flange installed and insulated.

4. Phase 3 – coordinate with owner for rotation of hallways. Owner must coordinate locating people and close coordination required. Work will start with dust barrier using plastic to seal off north south hallways from selected hallways by owner. Remove all ceilings, grid, ductwork to be demolished, penthouse air handlers and ductwork, and doors. Secure all ceiling devices, protect smart boards with dust protection. Locate furniture to center of room or as desired for installation work. Provide plastic dust covers. Install new ductwork, extend hot water piping from north south hallways valves, install controls, install new air handlers and extend ductwork, install new ceiling and grid, install new lights and controls, extend power to new vav boxes, new variable frequency drives for air handlers, and chill water runouts to air handlers. Install new doors and hardware, clean up floors and spaces, and return furniture as found. Test and confirm systems with inspections of trades to include controls for a ready to occupy space. Test and balance system and when complete offer to owner the hallways for occupancy and inspection by contracting officer.

5. Phase 4 – coordinate with owner – demolish middle chiller and south condenser pump (if seasonally able with permission from contracting officer), install new condenser water manifold assembly, new condenser pumps and new chiller. Perform all electrical work, install variable frequency drives for pumps, and when the middle chiller and condenser pumps for south and middle chillers installed then test and start them. Valves on the condenser manifold will allow for maintaining cooling using north chiller. As work is complete the south and middle chiller will be used and the north pumps removed with installation of new for a complete plant. In course of interior work the middle cooling tower will be service with new drive shaft, motor, variable frequency drive, power connections, new make up water valve and float with adjustment, a thorough cleaning of tower, controls installed and checked out, and a complete test for proper operation. Provide new oil in gear box and fill to correct level. Bring tower on line and check for correct operation and water levels.