TFF MILCON D303001andD304006 REV5.docx

D303001 CHILLED WATER SYSTEMS

Provide high-efficiency air-cooled chillers. Evaporators shall be Tube and Shell only. Plate and frame evaporators shall not be used on CLNC. Shell and Tube evaporators must include factory installed immersion heater for freeze protection.

Provide constant primary/variable secondary pumping systems on single chiller systems greater than 60 tons and on multiple chiller systems. Primary pumping may be used only on single chiller systems less than 60 tons. Keep flow through the chiller constant; do not use variable primary flow. A buffer tank must be provided on all systems to provide thermal inertia. A buffer tank is required, if the loop is not large enough to allow for proper chiller stage down time. Provide multiple chillers for loads greater than 160 tons with each chiller sized for 50% of the total facility cooling load.

Chillers that are less than 100 tons shall have scrolls compressors, and size the chiller to allow for 50% redundancy. Screw compressor shall be used for larger loads, but shall require additional chiller redundancy.

For unique facilities that exhibit widely variable occupant loading, multiple dissimilar sized chillers must be provided as appropriate for the low occupancy condition and fully occupied condition. Provide chillers capable of low load levels, in addition, if several small chillers are needed, then pipe to a common header. For air cooled compressor scroll, if low load levels are required, then chiller is to include hot gas bypass to allow unit operation to 10% of full load to prevent compressors from staging on and off.

The chillers must be located in an exterior equipment yard area and properly spaced from each other and other equipment away from building perimeter. The air-cooled chiller(s) must be located outside on a 6-inch thick reinforced concrete housekeeping pad. Provide heat tape to ensure freeze protection as low as 10°F on chilled water piping and any other associated appurtenances. Refer to the MCB Camp Lejeune mechanical policy for the requirements for phase and voltage protection requirements for chillers. Provide emergency chiller connections consisting of isolation valves and blind flanges.

Low ambient capability must be provided to allow chillers to operate in temperatures as low as 15°F.

All coils must have the approved coatings that pass a salt-spray test conducted per ASTM B117 for duration of at least 6,000 hours and provide a minimum of loss of heat transfer due to the thickness of the coating. Electrofin coating is preferred.

Coil coating shall be a flexible epoxy polymer e-coating uniformly covering the coil. Coating shall meet 5B rating for Cross Hath Adhesion according to ASTM D3359-97. Coils shall include a top coat to prevent UV degradation of the e-coating film. Top coating shall have a dy film thickness from 120 to 170µm. Field coated coils will not be accepted.

All Coils must be constructed of Aluminum Alloy 9153. Aluminum Alloy 3102 coils will not be accepted.

Chillers shall include thermal dispersion type flow switches. Paddle type flow switches will not be accepted.

Chillers shall include phase loss with under/over voltage protection with LED indication of the fault type.

Chillers shall have a centrally located weatherproof control panel to include a DDC microprocessor controller. The Control box shall be designed in accordance with NEMA 3R rating. Controllers and screens must be located within the panel and not exposed to sunlight.

Chillers shall be equipped with louvered coil guards top and bottom. Condenser fans shall have sound attenuating boxes or columns.

Provide the approved quantity, size, spacing, material, and height of bollards around all yard equipment.

Provide insulation and vapor barriers on all chilled water equipment. Use polyisocyanurate with Aluminum cover.

Provide complete system flushing and start-up for the entire chilled water system including piping.

Provide air vents at all terminal equipment and system high points, drains at system low points, and provide chemical treatment equipment for chilled water piping system.

Provide emergency “T” connects with butterfly valves and end cover plates on all chilled water systems to allow for emergency temporary chiller hook ups.)

Chiller shall include “Y” type strainers with the following minimum Cv and screen area values listed below.

(in²)

Startup must include operational testing of chiller equipment and full commissioning.

D304006 CHILLED WATER DISTRIBUTION SYSTEMS

For buildings with less than 60 tons of cooling load, provide a constant primary pumping system to serve the HVAC chilled water equipment throughout the facility. For buildings with more than 60 tons of cooling load, provide a constant primary/variable secondary pumping arrangement with a single primary pump per chiller. For buildings with more than 160 tons of cooling load, provide a constant primary/variable secondary pumping arrangement with two primary pumps per chiller. Secondary variable pumps shall be dual arm or lead lag. In all cases, keep flow through the chiller constant.

For building less than 160 tons, provide two primary pumps or two secondary pumps as appropriate with each pump sized for 100% flow. For buildings with more than 160 tons, provide three secondary pumps, each sized for 50% of maximum building flow. Two pumps must operate as duty pumps and the third must act as standby. Provide a control sequence to rotate pump duty/standby assignments monthly and equalize running hours.

Provide valves and related chilled water system appurtenances. Provide an expansion tank and air/solids separator in chilled water system. “Triple duty” or “multi-purpose” valves that combine a check valve, throttling valve, and shut-off valve must not be used for the chilled water system. Provide air vents at all terminal equipment and system high points for air control. Provide factory installed strainer package with victolet coupling.

Provide steel and copper chilled water supply and return piping to serve the HVAC equipment throughout the facility. Insulate piping with cellular glass insulation on all above ground chilled water distribution piping.

Provide air vents at all terminal equipment and system high points for air control. Provide a shot type feeder for manual chemical feed for the chilled water piping system.

Provide thermal mass capability in the chilled water system to insure proper control and longevity of chillers by using inertia tanks. Provide inertia tanks, sized per chiller manufacturer recommendation to ensure stability of operation and temperature set point control. Total chilled water system volume must be a minimum of 7 gallons per ton of cooling. Provide an insulated storage tank within the mechanical room in order to meet this requirement.

Provide insulation, vapor barrier, and aluminum jacketing on piping exposed to outdoors. Install heat tracing on piping to ensure freeze protection to 10°F.

Provide system flushing and startup for the chilled water piping system.

Provide complete startup and operational testing of all chilled water systems.