1、Designation: F 1948 05An American National StandardStandard Specification forMetallic Mechanical Fittings for Use on Outside DiameterControlled Thermoplastic Gas Distribution Pipe and Tubing1This standard is issued under the fixed designation F 1948; the number immediately following the designation
2、indicates the year oforiginal adoption or, 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 requirement
3、s and test methodsfor the qualification of metallic mechanical fittings for use withoutside diameter controlled thermoplastic gas distribution pipeand tubing as specified in Specification D 2513.1.2 The test methods described are not intended to beroutine quality control tests.1.3 This specification
4、 covers the types of mechanical fittingsdescribed in 3.3.1.4 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units which are provided for informationonly and not considered standard.1.5 The following safety hazard
5、s caveat pertains only to thetest method portion, Section 7, of this specification. Thisstandard may involve hazardous material, operations andequipment. This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this
6、standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.6 The text of this standard references notes and footnoteswhich provide explanatory material. These notes and footnotes(excluding those in tables and figures), sha
7、ll not be consideredas requirements of the standard.2. Referenced Documents2.1 ASTM Standards:2D 638 Test Method for Tensile Property of PlasticsD 1598 Test Methods for Time-To-Failure of Plastic PipeUnder Constant Internal PressureD 1600 Abbreviations of Terms Relating to PlasticsD 2513 Specificati
8、on for Thermoplastic Gas Pressure Pipe,Tubing and FittingsF 412 Definitions of Terms Relating to Plastic Piping Sys-temsF 1588 Test Method for Constant Tensile Load Test2.2 ASME Standard:ASME B 31.8 Gas Transmission and Distribution PipingSystems32.3 Federal Specification:OPS Part 192 Title 49, Code
9、 of Federal Regulations42.4 Other Document:PPI TR-4 Recommended Hydrostatic Strengths and DesignStresses for Thermoplastic Pipe and Fitting Compounds53. Terminology3.1 Definitions are in accordance with Definitions F 412unless otherwise specified. Abbreviations are in accordancewith Abbreviations D
10、1600 unless otherwise specified.3.1.1 The gas industry terminology used in this specificationis in accordance with ASME/ANSI B31.8 or United StatesCFR 49 Part 192 unless otherwise indicated.3.1.2 The term “pipe” used herein refers to both pipe andtubing unless specifically stated otherwise. The term
11、 “fitting”refers to a mechanical connecting device as described in 3.2.5and 3.2.7.3.2 Definitions:3.2.1 Category 1 mechanical fitting, nfitting for assem-bling pipe, which includes a compression zone(s) to providefor pressure integrity, leak tightness, and resistance to endloads sufficient to cause
12、no less than 25 % elongation of thepiping, as described in this standard.3.2.2 Category 2 mechanical fitting, nfitting for assem-bling pipe, which includes a compression zone(s) to provide1This specification is under the jurisdiction ofASTM Committee F-17 on PlasticPiping Systems , and is the direct
13、 responsibility of Subcommittee F17.60 on Gas.Current edition approved August 1, 2005. Published August 2005. Originallypublished in 1999. Last previous edition approved in 1999 as E 194899ae12For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at ser
14、viceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from the American Society of Mechanical Engineers, Three ParkAve., New York, NY, 10016-5990.4Available from the Office of Pipeline Safety, Research and Specia
15、l ProgramsAdministration, U.S. Department of Transportation, 400 Seventh Street, S.W.,Washington, DC, 20006-1301.5Available from the Plastics Pipe Institute, 1801 K Street N.W., Suite 600K,Washington, DC, 20006-1301.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken
16、, PA 19428-2959, United States.for pressure integrity and leak tightness; Category 2 fittings donot provide for resistance to end loads.3.2.3 Category 3 mechanical fitting, nfitting for assem-bling pipe, which includes a compression zone(s) for pressureintegrity, leak tightness, and resistance to en
17、d loads; thenominal size of the fitting shall be 4 and larger in diameter.3.2.3.1 DiscussionResistance to end loads shall be equalto or greater than the maximum thermal stress that would beproduced by a temperature change of 100F (55C) (forformula, see Annex A1).3.2.4 joint, nthe location at which t
18、wo or more pieces ofpipe, or a pipe and a fitting, are connected (an installedcoupling has two joints).3.2.5 joint, mechanical, na connection between pipingcomponents employing physical force to develop a seal orproduce alignment.3.2.6 maximum allowable operating pressure, MAOP,nof the fuel gas pipi
19、ng system, in psig, as determined inaccordance with US DOT CFR, Title 49, Part 192.121, and asrepresented in the following:MAOP5P52 3 S/R1!xf (1)where:S = the pipe materials HDB as published in PPI TR 4,R = the pipes dimension ratio determined by dividing thepipes specified nominal outside diameter
20、by the pipesspecified nominal wall thickness, andf = design (derating) factor for thermoplastic fuel gaspiping as set by the authority having jurisdiction. In theUnited States, the design factor is cited in CFR, Title49, Part 192.121.3.2.7 mechanical fitting, nfitting for making a mechanicaljoint to
21、 provide for pressure integrity, leak tightness, and,depending on category, as defined in this standard, resistance toend loads.3.3 Types of Mechanical Fittings:3.3.1 clamped insert fitting, nmechanical fitting used tomake a mechanical joint that utilizes external clamps, or othermechanical devices,
22、 to form a pressure seal between thereinforcing tubular stiffener and the surface of the pipe.3.3.2 compression fitting, nmechanical fitting used tomake a mechanical joint by compressing either externally,internally, or radially to form a pressure seal between the fittingand the surface of the pipe.
23、3.3.3 compression gasket fitting, nmechanical fitting usedto make a mechanical joint that utilizes a compression nut,tightening ring, bolts, or any other device to compress gasket-ing onto the surface of the pipe to form a pressure seal.3.3.4 stab-type fitting, nmechanical fitting used to make amech
24、anical joint in which a seal is achieved by radial com-pression of a gasket between the outside diameter (OD) of thepipe and the inside diameter (ID) of the fitting.4. Material4.1 The physical properties of each material used to producethe fitting shall be available from the fitting manufacturer upo
25、nrequest.4.2 Specifications outlining the physical and chemical prop-erties of all fitting materials shall be available from the fittingmanufacturer upon request.NOTE 1Materials in long-term contact with natural gas of line qualityand LP gas vapor should be demonstrated to not adversely effect thepe
26、rformance of the fitting.NOTE 2Materials should have a demonstrated resistance to environ-mental stress cracking when exposed, under stress, to chemical com-pounds encountered in or external to gas piping systems, and a demon-strated resistance to bacteriological decomposition. Such compoundsinclude
27、, but are not limited to, ice thawing chemicals, fertilizers, insecti-cides, herbicides, leak detection fluids, acids, bases and antifreezesolutions used to thaw frozen lines.5. Dimensions5.1 The dimensions and tolerances shall be determined bythe manufacturer.6. Qualification Requirements6.1 Genera
28、lUnless otherwise specified, each nominal sizeof fitting shall be tested. Testing the fitting with the thickestwall pipe for which the fitting is designed qualifies that type offitting for use with pipe of lesser wall thickness.6.1.1 Mechanical joint qualification shall be performed onassembled join
29、ts using the fitting manufacturers joining pro-cedure. All mechanical fittings offered by the manufacturershall be capable of meeting the requirements of this standardwhen connecting thermoplastic piping materials complyingwith Specification D 2513. It is not the intent of this standardto require th
30、e testing of all fitting configurations (that is, tee,ells, etc.) but each joint design in each size.6.1.2 All mechanical fittings described in 3.3 shall have aninternal pipe reinforcing tubular stiffener that extends at leastunder the seal and gripping device (where used).6.2 Performance Requiremen
31、ts:6.2.1 Tensile StrengthThe pipe joint shall accommodatethe tensile loads, when tested in accordance with 7.2.6.2.1.1 Category 1The joint shall provide resistance to aforce on the pipe joint equal to or greater than that which willcause no less than 25 % elongation of the pipe, or which causesthe p
32、ipe to fail outside the joint area when tested in accordancewith 7.2.6.2.1.2 Category 2Joint design that only provides a seal.A mechanical joint designed for this category excludes anyprovisions in the design of the joint to resist axial pulloutforces; therefore, tensile tests are not required.6.2.1
33、.3 Category 3Joint of nominal pipe size 4 and largerin diameter shall provide resistance to a force on the pipe jointequal to or greater than the maximum thermal stress that wouldbe produced by a temperature change of 100F (55C) (forformula, see Annex A1).NOTE 3Category 3 has a manufacturers rated p
34、ipe end restraint lessthan the value required to yield the pipe as outlined in 6.2.1.1 (Category1).6.2.1.4 Joint restraint capabilities less than as defined in6.2.2.1 and 6.2.2.3 shall constitute failure of the test.6.2.2 Temperature Cycling TestThe mechanical joint shallprovide a pressure seal afte
35、r 10 cycles of the temperaturecycling test when tested in accordance with 7.3.F19480526.2.3 Constant Tensile Load TestThe joint shall not fail byleakage or pullout when loaded to an axial tensile stress of1320 psi (9101 kPa) and tested in accordance with 7.4.6.3 Elevated Temperature Sustained Pressu
36、reThe fitting,joint or pipe in the area affected by the fitting shall not fail asdefined in Test Method D 1598, when tested in accordancewith 7.5. The fitting or joint meets this requirement when testedin accordance with any one of the three conditions (A, B, or C)listed in 7.5.7. Test Methods7.1 Ge
37、neralThe test methods in this specification covermechanical joint designs. Test methods that are applicable fromother specifications are referenced in the paragraph pertainingto that particular test.7.1.1 ConditioningUnless otherwise specified, conditionthe specimens (pipe and fittings) prior to joi
38、ning at 73.4 63.6F (23 6 2C) for not less than 16 h.7.1.2 Test ConditionsConduct the testing at the standardlaboratory temperature of 73.4 6 3.6F (23 6 2C) unlessotherwise specified.7.1.3 Test SpecimensTest joints shall be prepared with theappropriate size thermoplastic pipe, complying with the dime
39、n-sional requirements of Specification D 2513, in accordancewith the manufacturers joining procedures.7.1.4 Precautions and Safety ConsiderationsIt is stronglyrecommended that liquid be used as the pressurizing fluid whentesting systems that may fail in a brittle manner (specificallyPVC systems). If
40、 that is not possible, the test specimens mustbe placed in a strong chamber at all times when pressurized.Also, fittings as specified in 6.2.1.2 should be restrained toprevent pull-out during testing.7.2 Tensile Strength Test:7.2.1 The test pipes, for sizes below NPS 4, shall beprepared so that the
41、minimum length of unreinforced pipe froma joint being tested is equal to five times the nominal outsidediameter of the pipe being tested. The test pipes, for sizes NPS4 and above, shall be prepared so that the minimum length ofunreinforced pipe from a joint being tested is equal to threetimes the no
42、minal outside diameter of the pipe being tested, butin no case less than 12 in. (304 mm). It is permissible to testmultiple joints together, provided that the minimum length ofunreinforced pipe (as stated above) exists on at least one joint.7.2.2 The apparatus and report shall be as specified in Tes
43、tMethod D 638. Test six joints.7.2.3 The test shall be conducted at 73.4F 6 3.6F (23C6 2C).7.2.4 The speed of the testing shall be 0.2 in. (5 mm)/min.625 %.7.2.5 Failure of any sample shall constitute failure of thetest.7.3 Temperature Cycling Test:7.3.1 The test shall be conducted on six of the sma
44、llest andsix of the largest nominal pipe sizes of each mechanical jointdesign and assembled as outlined in 6.1.1.7.3.2 Leak test specimens at ambient temperature at 76 3psig (48.3 6 20.7 kPa) and a minimum of 1.5 X MAOP.7.3.3 Cool specimens to a temperature of 20F6 3.6F(29C 6 2C) and maintain for a
45、minimum of 2.5 h.7.3.4 Condition specimens to a temperature of 140F63.6F (60C 6 2C) and maintain for a minimum of 2.5 h.7.3.5 Repeat 7.3.3 and 7.3.4 for a total of 10 cycles.7.3.6 Pressurize 50 % of the specimens of each size at 7 63 psig (48.3 6 20.7 kPa) and the remaining 50 % of each sizeat 1.5 3
46、 MAOP of the piping material and SDR for which thefittings are designed to be used. Leak test first at 140 6 3.6F(60 6 2C) and then at 20 6 3.6F (296 2C).NOTE 4If immersion is used for leak testing, and the design of thejoint is such that air can be trapped within the joint assembly, allowadequate t
47、ime for all air trapped within the joint to escape prior toobserving for leaks.7.4 Constant Tensile Load Joint Test:7.4.1 One specimen of each nominal pipe size shall betested in accordance with Test Method F 1588 for a minimumof 1000 h at an internal pressure between 4 psig (27.6 kPa) andthe pipe M
48、AOP.7.4.2 Failure of the specimen shall constitute failure of thetest.7.5 Elevated Temperature Sustained Pressure Test:7.5.1 The test shall be conducted on six of the smallest andsix of the largest nominal pipe sizes of each mechanical jointdesign and assembled as outlined in 6.1.1.7.5.2 The apparat
49、us and report shall be as specified in TestMethod D 1598.7.5.3 The assembled joints shall be tested in accordancewith Test Method D 1598 with the exception that it is notrequired that 12 in. or five times the nominal outside diameterof the pipe used in conducting the test be placed on each sideof the fitting tested. The test shall be conducted at one of thetime/temperature/hoop stress combinations shown in Table 1with the test pressure calculated using the following equation:P52SDR21(2)where:P = test pressure, psig,S = h
