rating.
2.7.4
Refrigerated Air Dryer
a.
Provide a refrigerant dryer sized for continuous operation to
reduce the compressed air dew point temperature, at 20 psig output
pressure, to 30 degrees F with average tank pressure of 80 psig
and ambient air temperature between 55 and 95 degrees F. Provide
dryer with an automatic condensate drain trap with a manual
override feature. Provide refrigerant gages for suction lines.
b.
Connect dryer in the high pressure piping between tank and
pressure -reducing valve.
2.7.5
Compressed Air Discharge Filter
a.
Provide dry type filter, 99 percent efficient in removing oil and
solid particles at 0.03 micron rating, with baked enamel steel
housing and manual drain valve. Provide visual indicator to show
when oil filter element should be changed.
b.
Provide disposable filter directly before each control module with
pneumatic outputs, Disposable filter shall eliminate 99.99
percent of all liquid or solid contaminants 0.1 micron or larger.
Provide filter with easy to remove fittings.
2.7.6
Air Pressure-Reducing Station
Provide pressure-reducing valve (PRV) with field adjustable range of 0 to
50 psig discharge pressure, with inlet pressure of 70 to 90 psig. Provide
factory-set pressure relief valve to relieve overpressure downstream of PRV
exceeding 25 psig. Provide inlet pressure gage with range of 0 to 100 psig
and outlet pressure gage with range of 0 to 30 psig. For two pressure
systems, provide an additional PRV and outlet pressure gage.
2.7.7
Pneumatic Tubing
2.7.7.1
Copper Tubing
Provide ASTM B 75 or ASTM B 88M ASTM B 88 rated tubing. Tubing 0.64 mm
0.375 inch outside diameter and larger shall have minimum wall thickness
equal to ASTM B 88M ASTM B 88, Type M. Tubing less than 10 mm 0.375 inch
outside diameter shall have minimum wall thickness of 0.64 mm 0.025 inch.
Concealed tubing shall be hard or soft copper; multiple tubing shall be
racked or bundled. Exposed tubing shall be hard copper; rack multiple
tubing. Tubing for working pressures greater than 30 psig shall be hard
copper. Bundled tubing shall have each tube numbered each six feet
minimum. Racked and individual tubes shall be permanently identified at
each end. Fittings shall be solder type ASME B16.18 or ASME B16.22, using
ASTM B 32, 95-5 tin-antimony solder, or compression type ASME B16.26.
2.7.7.2
Polyethylene Tubing
**************************************************************************
NOTE: Systems that are critical and systems
required for smoke removal shall have tubing of
noncombustible material only.
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SECTION 15910N
Page 51
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