permanently lubricated ball bearings.
2.22.2
Pressure Vessels
Pressure vessels shall conform to ASME BPVC SEC VIII D1 or UL 207, as
applicable for maximum and minimum pressure or temperature encountered.
Where referenced publications do not apply, pressure components shall be
tested at 1-1/2 times design working pressure. Refrigerant wetted carbon
steel surfaces shall be pickled or abrasive blasted free of mill scale,
cleaned, dried, charged, and sealed. Where service temperatures below
minus 6.7 degrees C 20 degrees F are encountered, materials of construction
shall be low temperature alloy carbon steel.
2.22.2.1
Hot Gas Muffler
Unit shall be selected by the manufacturer for maximum noise attenuation.
Units rated for 105.5 kW 30 tons capacity and under may be field tunable
type.
2.22.2.2
Liquid Receiver
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NOTE: Delete the last sentence if inapplicable.
Insulation may be required if the room where the
receiver is located can reach a higher temperature
than the saturation temperature of the refrigerant.
Insulation is generally not needed in most
applications.
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Receiver shall be designed, filled, and rated in accordance with the
recommendations of ARI 495, except as modified herein. Receiver shall be
sized so that it is never filled beyond 80 percent of its total capacity.
The remaining 20 percent shall allow for liquid expansion. Receiver shall
be provided with a relief valve of capacity and setting in accordance with
ASHRAE 15. Receiver shall be fitted to include an inlet pipe; an outlet
drop pipe with oil seal and oil drain where necessary; two bulls-eye liquid
level sight glass in same vertical plane, 90 degrees apart and
perpendicular to axis of receiver or external gauge glass with metal guard
and automatic stop valves; [a thermal well for thermostat;] [a float switch
column;] [external float switches;] purge, charge, equalizing,
pressurizing, plugged drain and service valves on the inlet and outlet
connections. Receiver shall be factory insulated with not less than 25 mm
1 inch thick, 100 percent adhesive bonded, vaportight, flexible,
closed-cell elastomer and finished with two coats of solvent base PVC
protective coating or 0.41 mm 0.016 inch thick aluminum jacket.
2.22.2.3
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NOTE: An oil separator may be required if a system
has very low evaporator temperatures (minus 18
degrees C (0 degrees F) or less), or very long runs
of piping, or multiple compressors. Use ASHRAE
Handbook, Refrigeration Systems and Applications for
further guidance. Note that the inclusion of oil
separators will not decrease the need for using
proper pipe sizing and layout/sloping techniques to
ensure oil return.
SECTION 15652A
Page 36
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