2.3.2.3
Two-Way Valves
Two-way modulating valves shall have equal percentage characteristics.
2.3.2.4
Three-Way Valves
Three-way valves shall have equal percentage characteristics.
2.3.2.5
Duct Coil and Terminal Unit Coil Valves
Provide control valves with either flare-type or solder-type ends provided
for duct or terminal-unit coils. Provide flare nuts for each flare-type
end valve.
2.3.2.6
Valves for Chilled Water, Condenser Water and Glycol Service
a.
Bodies for valves 40 mm 1 1/2 inches and smaller shall be brass or
bronze, with threaded or union ends. Bodies for valves from 50 to
80 mm 2 inches to 3 inches inclusive shall be of brass, bronze or
iron. Bodies for 50 mm 2 inch valves shall have threaded ends.
Bodies for valves from 65 to 80 mm 2 1/2 to 3 inches shall have
flanged-end connections. Internal valve trim shall be brass or
bronze except that valve stems may be Type 316 stainless steel.
Water valves shall be sized for a [21 kPa] [3 psi] [_____]
differential through the valve at rated flow, except as indicated
otherwise.
Select valve flow coefficient (Cv) for an actual
pressure drop not less than 50 percent or greater than 125 percent
of the design pressure drop at design flow.
b.
Valves 100 mm 4 inches and larger shall be butterfly valves.
2.3.2.7
Valves for Hot Water Service
Valves for hot water service below 121 degrees C 250 Degrees F:
a.
Bodies for valves 40 mm 1 1/2 inches and smaller shall be brass or
bronze with threaded or union ends. Bodies for valves larger than
50 mm 2 inches shall have flanged-end connections. Water valves
shall be sized for a [21 kPa] [3 psi] [_____] differential through
the valve at rated flow, except as indicated otherwise. Select
valve flow coefficient (Cv) for an actual pressure drop not less
than 50 percent or greater than 125 percent of the design pressure
drop at design flow.
b.
Internal trim, including seats, seat rings, modulation plugs, and
springs, of valves controlling water hotter than 99 degrees C 210
degrees F shall be Type 316 stainless steel.
c.
Internal trim for valves controlling water 99 degrees C 210
degrees F or less shall be brass or bronze.
d.
Non-metallic parts of hot water control valves shall be suitable
for a minimum continuous operating temperature of 121 degrees C or
28 degrees C 250 degrees F or 50 degrees F above the system design
temperature, whichever is higher.
e.
Valves 100 mm 4 inches and larger shall be butterfly valves.
SECTION 15910N
Page 42
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