2.4.11
Galvanized Steel Shapes
ASTM A 36/A 36M to commercial weight of not less than 0.70 kg/square meter
2.3 ounces/square foot of single side surface.
2.4.12
Aluminum Sheets and Plates
ASTM B 209M ASTM B 209, Alloy 3003, H-14.
Sheets shall be lockforming
quality.
2.4.13
Aluminum Shapes
ASTM B 221M ASTM B 221, Alloy 6061, T-5 and T-6.
2.5
COMPRESSOR/CONDENSING UNITS
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NOTE: Delete the last sentence if an ammonia system
is not specified.
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[Compressor] [Condensing] unit shall be factory fabricated, assembled,
tested, packaged, and ready for full capacity operation after terminal
point connection and field charging with operating fluids. Unit shall
conform to ARI 520, ASHRAE 23, and ASHRAE 15. Ammonia systems shall also
conform to IIAR 2 and ARI 510.
2.5.1
Compressor
Compressors shall be selected for maximum energy efficiency and operating
reliability. Rotating parts shall be statically and dynamically balanced
at the factory to eliminate vibration at both partial and full load
conditions. Compressors shall be capable of continuous operation at lowest
partial load. Compressor over 7.5 kW 10 hp shall start from rest unloaded.
Compressor unloaders shall not be used when saturated suction temperatures
are below minus 4 degrees C 25 degrees F.
2.5.1.1
Construction
Compressors 1.5 kW 2 hp and less shall be the accessible, sealed
reciprocating type of either the open or hermetic design. Compressors
above 1.5 kW 2 hp shall be the accessible hermetic, sealed reciprocating
type. Compressors shall have integrally cast housings of close-grained
iron with an oil-level bull's eye, cast cylinder heads, cast aluminum or
forged steel connecting rods, and cast iron or forged steel crankshafts.
Main bearings shall be the sleeve-insert type. Ammonia service compressor
cylinder blocks and heads shall be fitted with self-draining water- or
refrigerant-cooled jackets where recommended by the manufacturer. Water
jackets shall be freeze protected.
2.5.1.2
Lubrication System
The lubrication system on compressors 2.2 kW 3 hp or larger shall be the
forced-feed, positive-displacement type with oil strainer. The oil pump
shall be reversible. Lube oil pressure gauge and failure switch shall be
provided for forced-feed lubrication type compressors. Compressor shall be
provided with an adjustable oil level regulator with a shutoff valve on
each inlet to allow removal of individual compressors without shutting down
the entire system.
SECTION 15652A
Page 18
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