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F-27855-10254
Guide Specification Text
F-27990-4 tc 12
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affiliated companies.
4. 2-way fluid system globe valves shall have the following characteristics:
a. Rangeability: Greater than 100:1 for all valves with flow coefficients of 0.4
and higher to provide stable control under light load conditions.
b. Maximum Allowable Seat Leakage: Standard and heavy duty valves must
be designed to meet ANSI Class V (0.0005 ml per minute per “of orifice
diameter per psi differential) up to 35 psi close off differential pressure and
ANSI Class IV seat leakage (maximum 0.01% of full open valve capacity)
above 35 psi with appropriate actuator. High temperature valves must meet
ANSI Class III seat leakage (maximum 0.1% of full open valve capacity).
c. The valve must be able to operate with a full-open operating differential of
no less than 87 psi.
d. Flow Characteristics: Modified equal percentage characteristics for
standard duty water applications and modified linear for heavy duty and
high temperature steam applications with gradual opening for light loads.
e. Sizing:
1 Two Position Water: Water: Line size or size using a differential pres-
sure of 1 psi.
2 Modulating Water: 5 PSI or twice the load pressure drop.
3 Pressure drop across steam valve at a maximum flow of 80 percent
of inlet pressure up to 15 psig and 42% of absolute (gage pressure +
14.7) inlet pressure above 15 psig inlet.
4 100 psi saturated steam maximum inlet pressure for heavy duty
bronze body globe valves ½”…2”.
5 150 psi saturated steam maximum inlet pressure for high tem-
perature bronze body globe valves ½”…2”.
6 35 psi saturated steam maximum inlet pressure for standard duty
bronze body globe valves ½”…2”.
5. Valves 3-Way mixing (two inlets and one outlet) NPS 2” and Smaller:
a. Operator, stem and plug assembly, and spring-loaded PTFE/EPDM valve
stem packing cartridge must be removable for future replacement to
restore the valves back to their original condition. Material grade properties
must meet the fluid temperature and pressure requirements:
1 Standard duty bronze body, 316 stainless steel vertical stem, brass
plug, and bronze seat, renewable packing cartridge, and screwed or
sweat ends. Valves shall have allowable media temperature of
20°F…281°F to assure reliability with dual temperature applications.
2 Heavy duty bronze body, 316 stainless steel vertical stem, 316
stainless steel plug, and 316 stainless steel seat, renewable disc and
packing cartridge, and screwed ends. Valves shall have allowable
media temperature of 20°F …340°F to assure reliability with dual
temperature applications.
6. 3-Way mixing hydronic system globe valves shall have the following characteristics:
a. Rangeability: Greater than 100:1 for all valves to provide stable
b. Maximum Allowable Seat Leakage: A port must be designed to meet ANSI
Class V (0.0005 ml per minute per “of orifice diameter per psi differential)
up to 35 psi close off differential pressure and ANSI IV seat leakage
(maximum 0.01% of full open valve capacity) above 35 psi with appropriate
actuator. B port must meet ANSI Class III seat leakage (maximum 0.1% of
full open valve capacity).
c. The valve must be able to operate with a full-open operating differential of
87 psi.
d. Flow Characteristics: Modified linear characteristics with gradual opening
for light loads.
Guide Specification Text
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