1、Designation: F 1795 00 (Reapproved 2006)An American National StandardStandard Specification forPressure-Reducing Valves for Air or Nitrogen Systems1This standard is issued under the fixed designation F 1795; the number immediately following the designation indicates the year oforiginal adoption or,
2、in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the design, construction, test-ing, and operating requ
3、irements for self-contained pressure-reducing valves for air or nitrogen systems.1.2 The values stated in this specification in inch-poundsunits are to be regarded as the standard. The SI equivalentshown in parentheses are provided for information only.2. Referenced Documents2.1 ASTM Standards:2F 99
4、2 Specification for Valve Label PlatesF 1685 Specification for Pressure-Reducing Manifolds forAir or Nitrogen Systems2.2 American National Standards Institute (ANSI):B1.1 United Screw Threads (UN and UNR Thread Form)3B1.20.1 Pipe Threads, General Purpose (Inch)3B16.11 Forged Steel Fittings, Socket-W
5、elding andThreaded3B16.25 Buttwelding Ends3B16.34 ValvesFlanged, Threaded, and Welded End32.3 Military Standards and Specifications:MIL-STD-167-1 Mechanical Vibrations of ShipboardEquipment (Type IEnvironmental and Type IIInternally Excited)4MIL-STD-740-1 Airborne Sound Measurements and Ac-ceptance
6、Criteria of Shipboard Equipment4MIL-S-901 Shock Tests, H.I. (High-Impact); ShipboardMachinery, Equipment and Systems, Requirements for4MIL-F-1183 Fittings, Pipe, Cast Bronze, Silver-Brazing,General Specifications for42.4 Government Drawings:Naval Sea Systems Command (NAVSEA):NAVSEA 803-1385884 Union
7、s, Fittings and Adapters Buttand Socket Welding 6000 PSI, WOG, NPSNAVSEA 803-1385943 Unions, Silver Brazing 3000 PSI,WOG, NPS, for UT InspectionNAVSEA 803-1385946 Unions, Bronze Silver Brazing,WOG for UT Inspection3. Terminology3.1 Definitions:3.1.1 accuracy of regulationthe amount by which thedowns
8、tream pressure may vary when the pressure-reducingvalve is set at any pressure within the required set pressurerange and is subjected to any combination of inlet pressure,flow demand, and ambient temperature variations within thespecified limits.3.1.2 bubble-sightno visible leakage over a 3-min peri
9、odusing either water submersion or the application of bubble fluidfor detection.3.1.3 external leakageleakage from the pressure-reducingvalve which escapes to atmosphere.3.1.4 fail-open flow capacitythe ability of the pressure-reducing valve to pass flow under any given set of pressureconditions whe
10、n, as a result of mechanical failure, it hasassumed a position of least resistance to flow.3.1.5 flow capacitythe ability of the pressure-reducingvalve to pass flow under any given set of pressure conditions.3.1.6 flow rate demandthe amount of flow demanded bythe system at any given time downstream
11、of the pressure-reducing valve.3.1.7 flow rate demand rangethe range over which theflow demand can vary.3.1.8 hydrostatic shell test pressure(s)The hydrostatic testpressures that the inlet and outlet of the pressure-reducingvalve is required to withstand without damage. Pressure-reducing valve opera
12、tion is not required during application ofshell test pressure, but the pressure-reducing valve must meetall performance requirements after the shell test pressure hasbeen removed.3.1.9 inlet operating pressure rangethe range over whichthe inlet pressure supplied to the pressure-reducing valve canvar
13、y under any operational conditions which the pressure-reducing valve can be subjected to in service.1This specification is under the jurisdiction of ASTM Committee F25 on Shipsand Marine Technology and is the direct responsibility of Subcommittee F25.11 onMachinery and Piping Systems.Current edition
14、 approved May 1, 2006. Published May 2006. Originallyapproved in 1997. Last previous edition approved in 2000 as F 1795 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, re
15、fer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.4Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 191115094, Attn: NPODS.1
16、Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.10 operating pressure(s)the pressures within thepressure-reducing valve during service.3.1.11 pressure ratingsthe pressure ratings of thepressure-reducing valve shall be as defined i
17、n the documentslisted in Table 1. The pressure ratings (also called pressure-temperature ratings) establish the maximum allowable working(service) pressures of a component (valve, end connections,and so forth) at various temperatures. For a pressure-reducingvalve, the pressure ratings may not be ide
18、ntical for the valveinlet and outlet.3.1.12 pressure-reducing valvea component which ac-complishes automatic regulation of the downstream pressure.In this component, the upstream pressure is reduced to thedesired downstream pressure.3.1.13 pressure reversala condition in which pressureexists at the
19、outlet of a pressure-reducing valve when theloading element is deactivated (set spring adjustment backedoff fully or dome charge vented off completely) and inletpressure is vented off.3.1.14 seat-tightnessthe ability of the pressure-reducingvalve to prevent leakage from the valve inlet to the valveo
20、utlet.3.1.15 self-contained pressure-reducing valvea pressure-reducing valve that does not use an external power source, suchas compressed air, electricity, or hydraulic fluid for operation,but instead uses the line fluid for operation.3.1.16 set pressurethe outlet pressure delivered by thepressure-
21、reducing valve at the time the pressure setting ismade. For the purposes of this specification, it will be assumedthat the setting is made when there is no flow demand on thepressure-reducing valve (“lock-up” condition), and thepressure-reducing valve is at surrounding ambient temperature.3.1.17 set
22、 pressure rangethe range of set pressures (setpressure limits) over which the pressure-reducing valve can beadjusted while meeting the performance requirements speci-fied.3.1.18 soft-seating insertthe insert, incorporated in eitherthe poppet or the seat of the pressure-reducing valve, whichensures b
23、ubble-tight seat tightness under all operating condi-tions.3.1.19 valve poppetthe part of the pressure-reducingvalve trim which established a rate of flow by moving towardor away from the valve seat.4. Classification4.1 Pressure-reducing valves shall be of the following types,sizes, pressure ratings
24、, and end connections, as specified inSection 5.4.1.1 TypesPressure-reducing valves shall be either TypeI (inlet outlet end connections of the same pressure rating) orType II (outlet end connection pressure rating lower than theinlet end connection rating) and specified in Section 5.4.1.2 SizesPress
25、ure-reducing valve sizes shall be18 NPS(10.2 mm),14 NPS (13.5 mm),38 NPS (17.2 mm),12 NPS(21.3 mm),34 NPS (26.9 mm), 1 NPS (33.7 mm), 114 NPS(42.4 mm), 112 NPS (48.3 mm), and 2 NPS (60.3 mm).4.1.3 Pressure RatingsPressure-reducing valves shallhave pressure rating(s) selected (see 3.1) from Table 1.
26、Thepressure rating(s) selected shall be specified in Section 5.4.1.4 End ConnectionsPressure-reducing valves shallhave end connections selected from those listed in Table 1 andspecified in Section 5.5. Ordering Information5.1 Ordering documentation for pressure-reducing valvesunder this specificatio
27、n shall include the following informationas required to describe the equipment adequately.5.1.1 ASTM designation and year of issue,5.1.2 Valve type (see 4.1.1),5.1.3 Valve inlet and outlet sizes (see 4.1.2),5.1.4 Pressure rating(s) (see 4.1.3),5.1.5 Type of end connections (see 4.1.4),5.1.6 Inlet op
28、erating pressure range.5.1.7 Set pressure and set pressure range, if other thanspecified (see 7.1.3).5.1.8 Flow rate demand range (see 7.1.1, S1.1.2).5.1.9 Accuracy of regulation required, if set pressure isbelow 10 psig (see 7.1.2).5.1.10 Tamper-proof set-point adjustment, if required (see6.1.9),5.
29、1.11 Supplementary requirements, if any (S1 through S4).5.1.12 Maximum vibration frequency and displacement am-plitude, if other than specified (see S1.1.4).6. Valve Construction6.1 Valves shall incorporate the design features specified in6.1.1-6.1.19.6.1.1 General RequirementsPressure-reducing valv
30、esshall be self-contained, requiring no external power source foroperation. The pressure-reducing valve shall be capable ofTABLE 1 Pressure Ratings for Pressure-Reducing ValveType of EndConnectionPressure RatingApplicable Documents forDimensional Details of EndConnectionsButt-welded ANSI B16.34 Clas
31、s150, 300, 400,600, 900, 1500,2500, or 4500ANSI B16.25Socket-welded ANSI B16.34 Class150, 300, 400,600, 900, 1500,2500, or 4500ANSI B16.11Threaded (taperedpipe thread)ANSI B16.34 Class150, 300, 400,600, 900,1500, or 2500ANSI B1.20.1 and ANSIB16.11Union end,Asilver-brazedMIL-F-1183 (O-ringtype) 400 l
32、b/in.2(2.758 MPa)MIL-F-1183 (O-ring type)400 lb/in.2(2.758 MPa)Union end,Asilver-brazed803-1385946 1500lb/in.2(10.342 MPa)803-1385946 1500lb/in.2(10.342 MPa)Union end,Asilver-brazed803-1385943 3000lb/in.2(20.64 MPa)803-1385943 3000lb/in.2(20.64 MPa)Union end,Abutt/socket weld803-1385884 6000lb/in.2(
33、41.369 MPa)803-1385884 6000lb/in.2(41.369 MPa)Other, as specified as specified as specifiedAFor union inlet and outlet end connections, only the pertinent dimensions listedin the applicable documents (Military Specification or NAVSEArequirements) shallapply. The valve shall be supplied with the thre
34、ad pieces only, without the tallpieces and union nuts.F 1795 00 (2006)2meeting all requirements of this specification and provideextended reliable operation when protected by a 5-m nominal/18-m absolute filter installed upstream and when subjected toconditions specified in Section 5.6.1.2 Materials
35、of ConstructionMaterial requirements forthe pressure-reducing valve shall be as follows: The pressurecontaining envelope (body, gas dome, or spring housing) shallbe 300 series corrosion-resistant steel (304, 304L, 316, or316L). Internal parts including springs, poppets, seal rings, andretainers shal
36、l be 300 series corrosion-resistant steel, nickel-aluminum bronze, nickel-copper (7030), or bronze. Othermaterials for both the pressure-containing envelope and inter-nal parts may be selected to assure compatibility with the linemedium, weldability, and to provide corrosion resistancewithout requir
37、ing painting, coating, or plating. Materials forcontacting parts shall be selected to minimize electrolyticcorrosion and galling.6.1.3 Pressure EnvelopeThe pressure-reducing valveshall be designed to pass a hydrostatic shell test at pressure(s)of at least 1.5 times the 100F (38C) pressure rating(s)
38、of thevalve without damage.6.1.4 Port ConfigurationThe pressure-reducing valveshall have in-line inlet and outlet ports.6.1.5 Pressure LinesAll pressure lines in the pressure-reducing valve shall be internally ported.6.1.6 Soft-Seating InsertA field replaceable soft-seatinginsert shall be incorporat
39、ed in the pressure-reducing valve.Soft-seating inserts shall be protected from direct flow im-pingement, excessive loading and extrusion, or any other effectjeopardizing their useful life. Soft-seating inserts shall be of thesimplest practical configuration to facilitate emergency re-placement manuf
40、acture where necessary.6.1.7 JointsThe bonnet or spring housing and bottom capshall be attached to the body by bolting, a threaded connection,or a threaded union connection.6.1.8 SpringsAny spring incorporated in the pressure-reducing valve shall not be compressed solid during operation.Spring ends
41、shall be squared and ground. Engagement ordisengagement of parts against spring compression shall not bepermitted.6.1.9 Set Point AdjustmentFor mechanical spring-loadedpressure-reducing valves, the set point shall be adjustableunder pressure and shall incorporate right-hand threads so thata clockwis
42、e rotation increases the set pressure. Means shall beused to prevent an accidental or inadvertent change in setpressure. The option of a tamper-proof set point adjustment(lead seal, and so forth) shall be available and provided ifspecified in Section 5. For gas-dome loaded pressure-reducingvalves, s
43、et point adjustment shall be in accordance with 6.1.10.6.1.10 Gas DomeFor gas-dome loaded pressure-reducingvalves, the set point shall be adjustable under pressure andshall maintain its charge without adjustment or recharge morefrequently than once a year to remain within its specifiedperformance en
44、velope. Upstream pressure shall be used toestablish dome load. Dome loading shall be accomplished bytwo valves installed in series, with a bleed-off valve in-between. If these valves are metal seated, they shall not seatdirectly into the structure of the dome so that damage or wearto the seating sur
45、faces would not require repair or replacementof the dome. Only a single dome penetration is allowed. Thevalves shall be operable by a standard-size hex wrench or othersuitable means. There shall be no external leakage past thethreads during dome bleeding. Flow from the bleed-off valveshall be ported
46、 in such a way that it does not impinge directlyon the person making the adjustment, cause excessive noise, orpotentially lead to ice formation within the dome loadingcircuit.6.1.11 ThreadsThreads shall be as specified in ANSIB1.1. Where necessary, provisions shall be incorporated toprevent the acci
47、dental loosening of threaded parts. The designshall be such that standard wrenches can be used on all externalbolting. Lock-wire shall not be used.Any exposed threads shallbe protected by plastic caps for shipping.6.1.12 AccessabilityAll internal parts of the pressure-reducing valve shall be accessi
48、ble for adjustment or service,without removing the pressure-reducing valve from the line.6.1.13 InterchangeabilityThe pressure-reducing valve in-cluding all associated piece parts, shall have part numberidentity, and shall be replaceable from stock or the manufac-turer on a nonselective and random b
49、asis. Parts having thesame manufacturers part number shall be directly interchange-able with each other with respect to installation (physical) andperformance (function). Physically interchangeable assem-blies, components, and parts are those that are capable of beingreadily installed, removed, or replaced without alternation,misalignment or damage to parts being installed or to adjoiningparts. Fabrication operations such as cutting, filing, drilling,reaming, hammering, bending, prying, or forcing shall not berequired.6.1.14 Nonmet
