Y1DA--630A4-26-401 MRI AHU Modification

n accordance with the existing AHU manufacturer specifications and VA specifications at http://www.cfm.va.gov/til/specs.asp. Work shall meet all VA design guidelines and requirements. Specific Requirement: The Contractor will furnish all on-site investigations, engineering, construction drawings, submittals, labor, materials, tools, supervision, equipment, safety, necessary to provide for the construction and functional performance testing of a new supplemental air-cooled chilled water system and hallway chilled water fan coil system for the Magnetic Resonance Imaging (MRI) Suite and its Air Handling Unit. The scope of work to be performed includes, but is not limited to, the following elements: The contractor will furnish and install a new air-cooled nominal 30-ton capacity electric chiller to supply chilled water to an existing chilled water coil in the existing Air Handler dedicated for the MRI suite in the basement of OPC building 15. The new air-cooled chiller system will utilize an integral skid mounted compressor, evaporator heat exchangers, power panel, control panel and chilled water buffer tank with a remote air-cooled refrigerant condenser located outside and adjacent to the building on grade. Both the interior below grade compressor and heat exchanger skid and the on-grade air cooled condenser skid shall be mounted atop concrete equipment pads. The poured in place of concrete equipment pads will be designed and constructed by the Contractor at locations within the below grade MRI suite s Mechanical Room and outside the building on grade adjacent to the building. Approximate locations for these two equipment pads are provided on the attached drawings. The existing Air Handling Unit chilled water coil is provided with chilled water by the general building chilled water system. This general building chilled water system is turned off during the heating season, but the MRI suite still requires mechanical cooling to maintain the necessary operating environments for the MRI machine and the patient and staff spaces due to the heat generated by the MRI equipment. The Contractor will design the new chiller equipment and piping to provide shoulder and winter month period supply of chilled water to the MRI AHU. The switch over from summer operation to cool weather operation for the chilled water system, and back again, shall be capable of performing remotely through connection and programming with the existing Honeywell Building automation system (BAS). The contractor shall design, furnish, install, program and commission a complete and fully operational Direct Digital Control system interface between the new air-cooled chiller and the piping connection actuated control valves to the existing Honeywell Building Automation System (BAS). The contractor will provide and install two new electrically actuated three-way flanged three (3) inch full port ball valves in the existing chilled water supply and return piping to the MRI AHU chilled water coil. These valves will be installed in the existing 3-inch diameter pipe sections of the general building chilled water lines supplying chilled water to the MRI Air Handling Unit (AHU) chilled water coil. The contractor will furnish and install two new manual operated full port three (3) inch ball valves upstream of the new three-way automated ball valves to provide isolation of the new three-way valves, the AHU and new air-cooled chiller from the general building chilled water piping system. The contractor will additionally provide two new manually operated full port three-inch ball valves downstream of the piping connections at the three-way valves from and to the new air-cooled chiller. The manual ball valves shall be provided with factory lockable handles for proper LOTO isolation operation. The contractor will furnish and install six (6) new nominal 18000 btu/h chilled water surface mounted fan coil units in the hallway that runs alongside the MRI suite and associated Mechanical room. The contractor will provide all necessary chilled water supply and return piping for the new fan coil units. The new chilled water supply and return lines shall be connected to the existing three inch (3 inch) chilled water lines between the new three-way valves and the MRI AHU chiller coil. This connection shall have manual operated isolation ball valves installed at the general piping connections. Drain valves will be installed at the isolation ball valves, and vent valves installed at the piping high points to facilitate gravity draining the fan coil supply and return lines. The new fan coil supply line will be provided with a flanged connection in-line circulating pump to provide necessary flows to achieve full fan coil system cooling capacity. The circulating pump will be provided with a wye strainer and isolation valves on each side of the pump to allow ease of replacement. The contractor will provide a piping and pump design which will supply the fan coils with chilled water flows as required for full design cooling capacity taking into account fan coil and piping system pressure drops and be capable of accommodating the full range of fan coil cooling operations, from no flow to full flow within the pumps recommended range of operations. The contractor will provide all necessary onsite investigations, site photographs and measurements for a complete, coordinated and fully functional mechanical system and construction design based on the as-built conditions of existing piping, Air Handling equipment, ductwork, lighting, electrical power distribution equipment and raceway, space availability, wall, floor and ceiling construction and constraints of the floor, walls and ceiling areas and outdoor area designated for the remote air condenser pad and equipment. The contractor will not rely on the availability or accuracy of existing construction or shop drawings in the proposal development, or on developing the new work design drawings. There are two optional locations for the outdoor ground mounted air-cooled condenser equipment shown on the drawings. The contractor shall evaluate both locations for suitability relative to optimized equipment protection, pipe routing, power availability and ground conditions. The VA COR will provide final determination of which location option is utilized. The MRI Air Handler is a DAIKIN Model # CAH012GDGM. The Scope of work includes providing all necessary investigations, design development calculations, construction and coordination drawings, design submittals, submittals required by specifications, equipment, including a liquid chiller system with a remote air cooled condenser, chilled water buffer tank, expansion tank, variable speed drive pumps to provide chilled water flow from the surge tank to the AHU coil, primary chiller pumps to pump water from the surge tank thru the evaporator heat exchanger back to the surge tank, side stream chemical treatment assembly, piping, fittings, vibration isolation connections between the chiller and the piping connections, refrigeration piping and accessories, chilled water piping, fan coil equipment, fan coil condensate collection and pumping system including piping to a sanitary drain pipe connection point (no condensate water can drain across the floor to a drain), manual and automated control devices, analog and DDC system sensors (temperature of air and li