FedCon/South Bay Joint Venture is tasked to renovate the HVAC (Heating, Ventilating and Air Conditioning) system in the Logistics Readiness Section (south-end) of building 224.
Mechanical – B224 Logistics Readiness Squadron
1.1.1 Design the new HVAC system to support chilled water. Currently, building 224 is not connected to the JBSA-Randolph chilled water loop. The design must account for future connection to the JBSA-Randolph chilled water loop.
1.1.2 Provide and install new completely finished, operating and fully functional HVAC system to service the project areas identified within building 224 ready for instantaneous use by the government.
1.1.3 At a minimum, the new HVAC system shall include all components shown on the tertiary diagram (attached as Appendix G) to make the HVAC system complete and usable.
1.1.4 Acquire all information to take the customer concept design to a 100% design. Responsible to conform to the Appendix C Design Guideline, as this is what will be reviewed upon each iteration of design. Address all Government comments in the progressing stage of design and may hold a meeting, as needed, to discuss these comments. Responsible to address any discrepancies with the proposed design and the applicable codes (referenced in Specification 01 00 00). Applicable codes shall take precedence over this SOW and conceptual drawings in the case of a discrepancy.
1.1.5 Perform a thorough load investigation to find the cooling peak load requirements for Building 224, demanded by each zone. The (DB) contractor shall also perform a building and submit a copy to the government representative prior to beginning construction.
All new AHUs shall include variable frequency drives (VFDs). The government does not intend on the variable air volume (VAVs), or the contractor’s alternate solution, to be the sole component controlling the air flow.
1.1.7 Integrate a VAV System within the design of this project. If a VAV System is not feasible based on the true requirement of the building or the lack of available space, the contractor shall recommend such a system that shall satisfy the requirement for maintaining satisfactory comfort levels in the LRS section (south-end) of Building 224.
1.1.8 Provide and install VAV terminal units and all associated components to include, but not limited to, thermostatic sensors, pressure sensors, hangers, supports, dampers, etc. necessary to provide proper cooling, and heating conditions within the project area.
1.1.9 Design and construct (if required) a new larger mechanical room on the east side of B224, to house the larger/additional AHU and associated equipment. This design shall ensure that the structural components of the building can support the additional dead, live and dynamic loads of the mechanical equipment.
1.1.10 Not be limited to any items discussed within this SOW, but shall adhere to Section 01-04-01 Design–Build Supplement and ensure design functionality and commissioning of this contract.
1.1.11 The design of the HVAC system shall be IAW UFC 3-410-01; outdoor design condition for cooling shall be based on 1% WB temp, heating shall be based on 99% DB temperature. Indoor design condition for comfort cooling shall be 78F with RH equaling to outdoor condition or a maximum of 50%.
1.1.12 Provide and install new, high efficiency, variable air volume (VAV) air-handling units (AHU) with hot water heating coil and dehumidification to provide ventilation, cooling and heating to all spaces within the project area of the building. AHU shall be equipped with freeze stats and airflow interlocks to prevent condenser operation when AHU is not operating or is failing to discharge air (i.e. broken belt). The AHU shall be installed on a 6-inch thick reinforced housekeeping pad using 3,000 psi concrete (28 day compressive strength) with vibration dampers. Concrete pad shall cure for a minimum of 7 days, before any installation can begin on the housekeeping pad.
1.1.13 Provide and install new, high efficiency, pad mounted air-cooled condensing unit properly sized to provide the cooling demand of the conditioned space to maintain indoor design conditions specified in UFC 3-410-01. The condensing unit shall be equipped with high and low pressure and temperature safeties and, in the case of 3 phase (applications) monitors as a minimum. Install OEM hail guard on condenser units.
1.1.14 Provide and install a new hydronic heating loop, complete with recirculating hot water (HW) pump and expansion tank, to supply hot water to the new AHUs hot water preheat and reheat coils. Hot water shall be generated using natural gas fired, high efficiency, sealed combustion condensing boiler. The hydronic boiler and the HW pump shall be installed on a new 6-inch thick reinforced housekeeping pad using 3,000 psi concrete (28 day compressive strength) with vibration dampers. Concrete pad shall cure for a minimum of 7 days, before any installation can begin on the housekeeping pad.
1.1.15 Provide and install new gas piping as necessary to meet the provisions of this SOW. The gas piping installed under the scope of this project shall be IAW NFPA 54. All gas piping, downstream of the low-pressure regulator to the equipment, shall be wrought iron or steel, with fittings of malleable iron conforming to ANSI B16.3. Piping connections to all gas burning equipment shall be made with rigid pipe and fittings. Provide dirt legs, isolation valves, unions, flex connections, gas pressure regulator, and automatic control valve to all equipment being fed by gas.
1.1.16 Provide and install new hydronic chilled water loop piping, complete with recirculating pump to supply chilled water to the new AHUs cooling coils. Chilled water loop piping shall be connected to the new air-cooled condensing unit. The chilled water (CHW) pump shall be installed on a new 6-inch thick reinforced housekeeping pad using 3,000 psi concrete (28 day compressive strength) with vibration dampers. Concrete pad shall cure for a minimum of 7 days, before any installation can begin on the housekeeping pad.
1.1.17 Contractor shall provide and install a new bypass chemical feeder along with backflow prevention device to maintain water quality for HVAC systems that minimizes corrosion, scale buildup, and biological growth for optimum efficiency of HVAC equipment without creating hazard to operating personnel or the environment. Closed loop hydronic systems, including heating hot-water and chilled water, shall have the following water qualities: (i) pH – maintain value within 9.0 and 10.5; (ii) “P” Alkalinity – maintain value within 100 and 500 ppm; and (iii) Boron – maintain value within 100 to 200 ppm.
1.1.18 Provide and install new ducting with insulation in the project area, see reference drawing located in Appendix H. All supply, return, intake, and exhaust ductwork shall be constructed of galvanized sheet metal. All duct fittings (including elbows, tees, and offsets) shall be constructed of rigid sheet metal. Non-metallic flexible duct run outs to air distribution devices shall be limited to 3’ in total length. Flexible duct shall only be used on straight run ducts (i.e. horizontal or vertical) and shall not be installed with elbows or with offsets greater than ½ duct diameter. All ductwork shall be insulated IAW applicable codes. Duct and air distribution devices shall meet the velocity requirements indicated in ASHRAE Handbook – HVAC Applications. ALL and every HVAC duct joint, fitting, component, and appurtenance shall be maintained within the most recent version requirements of ASHRAE 62.1 and SMACNA Advanced Cleanliness Level
1.1.19 Route all condensate drain to the nearest existing floor or roof drain. All drain piping shall be copper. The piping shall include a trap of sufficient depth to overcome static pressure of the unit. All piping, except in the mechanical room, shall be insulated with 1-inch thick mineral fiber or 1 ½-inch thick cellular glass.
1.1.20 Provide and install appropriately sized unitary gas or electric heater to provide freeze protection to the equipment installed within the mechanical rooms.
1.1.21 All new HVAC components shall be connected to the existing Direct Digital Control (DDC) system and existing installation-wide Energy Management Control System (EMCS) at Hangar 62. Provide and install all graphics and averaging graphing to the supervisory level to match the Front End. Provide all conduits, cables, termination boxes, and any additional items/accessories necessary to connect each of the HVAC components, installed as part this contract, back to the existing DDC controllers. All new HVAC components (points) shall be mapped back and relativized to the Energy Management Control System (EMCS) at Hangar 62. This system shall be proven to operate, by the contractor, with EMCS via a point verification test (PVT).
1.1.22 The new HVAC equipment shall be wired to the fire alarm for building 224 so that the fire department can immediately shut down the HVAC system in case of an emergency. The HVAC system must be compatible with, and controlled by, Johnson Controls equipment and must tie into the existing EMCS system. Work shall comply with the JBSA Specification 01-59-10.