service and shall comply with ASME B31.1. Metals of construction shall be
of Type 300 stainless steel, or [ferrous or copper] [ferrous] based.
Atmosphere exposed valve stems shall be stainless steel or corrosion
resistant metal plated carbon steel. Valve body connections shall be
brazed or welded socket, flanged or combination thereof. Threaded
connections shall not be used, except in pilot pressure or gauge lines
where maintenance disassembly is required and welded flanges cannot be
used. Valves shall be suitable for or fitted with extended copper ends for
brazing in-place without disassembly. Ferrous body valves shall be fitted
with factory fabricated and brazed copper transitions. To minimize system
pressure drops, where practicable, globe valves shall be angle body type,
and straight line valves shall be full port ball type. Control valve
inlets shall be fitted with integral or adapted strainer or filter where
recommended or required by manufacturer. Valves shall be cleaned and
sealed moisture-tight.
2.21.1
Refrigerant-Stop Valves
Stop valves shall be designed for use with the refrigerant used and shall
have pressure ratings compatible with system working pressures encountered.
Gate valves will not be acceptable.
2.21.1.1
Fluorocarbon Service
Valves 16 mm 5/8 inch and smaller shall be handwheel operated, straight or
angle, packless diaphragm globe type with back-seating stem, brazed ends,
except where SAE flare or retained seal cap connections are required.
Valves larger than 16 mm 5/8 inch shall be globe or angle type, wrench
operated with ground-finish stems, or ball valves, packed especially for
refrigerant service, back seated, and provided with seal caps. Refrigerant
isolation and shutoff valves shall have retained or captive spindles and
facilities for tightening or replacement of the gland packing under line
pressure as applicable. Stop valves shall have back-seating plated steel
stem, bolted bonnet in sizes 25 mm 1 inch OD and larger, integral or
flanged transition brazed socket. Valves, in sizes through 65 mm 2-1/2
inches shall be end-entry body assembly, full-port, floating ball type,
with equalizing orifice fitted chrome plated ball, seats and seals of
tetrafluoroethylene, chrome plated or stainless steel stem, and seal cap.
In sizes 100 mm 4 inch IPS and larger, and in smaller sizes where carbon
steel piping is used, valve bodies shall be tongue and groove flanged and
complete with mating flange, gaskets and bolting for socket or butt-weld
connection. Purge, charge and receiver valves shall be of manufacturer's
standard configuration.
2.21.1.2
Ammonia Service
Valves shall be straight or angle, packed, rising stem/handwheel fitted,
globe type. Stem shall be back-seating type, fitted with non-rotating,
self-aligning, retained lead alloy seat disc. In sizes 19 mm 3/4 inch IPS
and larger, bonnets shall be bolted and body end connections shall be
buttweld or tongue and groove flanged and furnished with mating flange,
gaskets, and fasteners. Mating flange shall be socket or buttweld
connection type. In sizes under 19 mm 3/4 inch IPS, threaded ends will be
acceptable. Ball valves constructed specifically for ammonia refrigeration
service are acceptable.
2.21.2
Check Valve
Valve shall be designed for service application, spring-loaded type where
SECTION 15652A
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