1、Designation:F72181(Reapproved 2014)An American National StandardStandard Specification forGage Piping Assemblies1This standard is issued under the fixed designation F721;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of las
2、t revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This specification covers details of gage p
3、iping assem-blies for pressure gages with optional provisions for additionalgages,pressure switches,transmitters,and so forth,for usewith steam,steam drains,feed water,condensate,fresh water,salt water,compressed air,fuel oil,and lubricating oil systems.1.2 The values stated in inch-pound units are
4、to be regardedas the standard.The values given in parentheses are forinformation only.2.Referenced Documents2.1 ASTM Standards:2A105/A105M Specification for Carbon Steel Forgings forPiping ApplicationsA106/A106M Specification for Seamless Carbon Steel Pipefor High-Temperature ServiceA108 Specificati
5、on for Steel Bar,Carbon and Alloy,Cold-FinishedA182/A182M Specification for Forged or Rolled Alloy andStainless Steel Pipe Flanges,Forged Fittings,and Valvesand Parts for High-Temperature ServiceA276 Specification for Stainless Steel Bars and ShapesA335/A335M Specification for Seamless Ferritic Allo
6、y-Steel Pipe for High-Temperature ServiceA576 Specification for Steel Bars,Carbon,Hot-Wrought,Special QualityB16/B16M Specification for Free-Cutting Brass Rod,Barand Shapes for Use in Screw MachinesB61 Specification for Steam or Valve Bronze CastingsB62 Specification for Composition Bronze or Ounce
7、MetalCastingsB75 Specification for Seamless Copper TubeB124/B124M Specification for Copper and Copper AlloyForging Rod,Bar,and ShapesB453/B453M Specification for Copper-Zinc-Lead Alloy(Leaded-Brass)Rod,Bar,and ShapesB466/B466M Specification for Seamless Copper-NickelPipe and Tube2.2 ANSI Standards:3
8、B16.11 Forged Steel Fittings,Socket Weld,and ThreadedB16.15 Cast Bronze Threaded Fittings2.3 Federal Specifications:4QQ-S-637 Steel Bar,Carbon,Cold Finished(StandardQuality,Free Machining)QQ-S-763 SteelBars,Wire,Shapes,andForgings,Corrosion-Resisting3.List of Assemblies3.1 This specification incorpo
9、rates 13 gage piping assem-blies as described in Table 1.4.General Requirements and Guidelines4.1 Fig.1 shows a typical piping assembly for bottom-connected gages and Fig.2 a typical piping assembly forback-connected gages.4.2 A siphon shall be used as shown in all gage applicationsfor steam systems
10、 to maintain a protective water seal betweenthe gage and the steam supply.4.3 Each assembly includes a test connection beyond thegage valve which consists of a tee with a14-in.NPT threadedplug in the branch.The plug is removable for the purpose ofinstalling a test gage for calibration.As an alternat
11、ive,a gagevalve that incorporates a built-in test connection integral withthe valve may be substituted for the gage valve and test tee.4.4 Root connections should be kept to a minimum byconnecting other instruments at the tee between the root andgage valves.There is no limit to the number of dead-en
12、d-typeinstruments that can be served from a single root connection.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 approved Aug.1,2014.Published Se
13、ptember 2014.Originallyapproved in 1981.Last previous edition approved in 2008 as F721 81(2008).DOI:10.1520/F0721-81R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to t
14、he 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 19111-5094,Attn:NPODS.Copyright ASTM Inter
15、national,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 However,each instrument should have its own shutoff valveand,if desired,a test tee may be fitted at each instrument.4.5 Two shutoff valves are generally used in each assembly,a root valve and a gage cutout valv
16、e.The gage valve may beeliminated and a single shutoff valve may serve as both a rootand gage valve provided the gage is within 6 ft(1.8 m)of theroot connection and readily accessible and the single shutoffvalve is fitted within 12 in.(300 mm)of the root connection.4.6 Pulsation dampeners are shown for certain assembliesbetween the test tee and gage and should be used in otherassemblies in which the gage may be subjected to pulsatingpressures,as from a reciprocating pump,air compressor,quick-act
