1、Designation: F1948 05 (Reapproved 2011)An 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 F1948; the number immediately following
2、the designation 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification cov
3、ers requirements and test methodsfor the qualification of metallic mechanical fittings for use withoutside diameter controlled thermoplastic gas distribution pipeand tubing as specified in Specification D2513.1.2 The test methods described are not intended to beroutine quality control tests.1.3 This
4、 specification 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 that are provided for information onlyand are not considered standard.1.5 The follow
5、ing safety hazards 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
6、the user of this 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
7、and figures), shall not be consideredas requirements of the standard.2. Referenced Documents2.1 ASTM Standards:2D638 Test Method for Tensile Properties of PlasticsD1598 Test Method for Time-to-Failure of Plastic PipeUnder Constant Internal PressureD1600 Terminology for Abbreviated Terms Relating toP
8、lasticsD2513 Specification for Polyethylene (PE) Gas PressurePipe, Tubing, and FittingsF412 Terminology Relating to Plastic Piping SystemsF1588 Test Method for Constant Tensile Load Joint Test(CTLJT)2.2 ASME Standard:ASME B 31.8 Gas Transmission and Distribution PipingSystems32.3 Federal Specificati
9、on:OPS Part 192 Title 49, Code 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 F412unless otherwise specified. Abbreviations are in ac
10、cordancewith Abbreviations D1600 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 specificall
11、y stated otherwise. The term “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 e
12、ndloads sufficient to cause 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 providefor pressure integrity and leak tightness; Category 2 fittings donot provide for res
13、istance to end loads.3.2.3 Category 3 mechanical fitting, nfitting for assem-bling pipe, which includes a compression zone(s) for pressure1This specification is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems , and is the direct responsibility of Subcommittee F17.60 on Gas.Curr
14、ent edition approved Feb. 1, 2011. Published March 2011. Originallypublished in 1999. Last previous edition approved in 2005 as E194805. DOI:10.1520/F1948-05R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book o
15、f ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.4Available from the Office of Pipeline Saf
16、ety, Research and Special ProgramsAdministration, U.S. Department of Transportation, 400 Seventh Street, S.W.,Washington, DC, 20006-1301.5Available from Plastics Pipe Institute (PPI), 105 Decker Court, Suite 825,Irving, TX 75062, http:/www.plasticpipe.org.1Copyright ASTM International, 100 Barr Harb
17、or Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.integrity, leak tightness, and resistance to end 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 w
18、ould beproduced by a temperature change of 100F (55C) (forformula, see Annex A1).3.2.4 joint, nthe location at which two 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 physi
19、cal force to develop a seal orproduce alignment.3.2.6 maximum allowable operating pressure, MAOP,nof the fuel gas piping 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 p
20、ublished in PPI TR 4,R = the pipes dimension ratio determined by dividing thepipes specified nominal outside diameter 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 d
21、esign factor is cited in CFR, Title49, Part 192.121.3.2.7 mechanical fitting, nfitting for making a mechanicaljoint to 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
22、fitting, nmechanical fitting used tomake a mechanical joint that utilizes external clamps, or othermechanical devices, 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 compres
23、sing either externally,internally, or radially to form a pressure seal between the fittingand the surface of the pipe.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-in
24、g onto the surface of the pipe to form a pressure seal.3.3.4 stab-type fitting, nmechanical fitting used to make amechanical 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 Th
25、e physical properties of each material used to producethe fitting shall be available from the fitting manufacturer uponrequest.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 l
26、ong-term contact with natural gas of line qualityand LP gas vapor should be demonstrated to not adversely effect theperformance 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
27、external to gas piping systems, and a demon-strated resistance to bacteriological decomposition. Such compoundsinclude, 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. Dime
28、nsions5.1 The dimensions and tolerances shall be determined bythe manufacturer.6. Qualification Requirements6.1 GeneralUnless 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 offitti
29、ng for use with pipe of lesser wall thickness.6.1.1 Mechanical joint qualification shall be performed onassembled joints using the fitting manufacturers joining pro-cedure. All mechanical fittings offered by the manufacturershall be capable of meeting the requirements of this standardwhen connecting
30、 thermoplastic piping materials complyingwith Specification D2513. It is not the intent of this standard torequire the 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 reinforc
31、ing tubular stiffener that extends at leastunder the seal and gripping device (where used).6.2 Performance Requirements: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 pi
32、pe joint equal to or greater than that which willcause no less than 25 % elongation of the pipe, or which causesthe pipe 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 an
33、yprovisions in the design of the joint to resist axial pulloutforces; therefore, tensile tests are not required.6.2.1.3 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 p
34、roduced by a temperature change of 100F (55C) (forformula, see Annex A1).NOTE 3Category 3 has a manufacturers rated pipe 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 shal
35、l constitute failure of the test.6.2.2 Temperature Cycling TestThe mechanical joint shallprovide a pressure seal after 10 cycles of the temperaturecycling test when tested in accordance with 7.3.6.2.3 Constant Tensile Load TestThe joint shall not fail byleakage or pullout when loaded to an axial ten
36、sile stress of1320 psi (9101 kPa) and tested in accordance with 7.4.6.3 Elevated Temperature Sustained PressureThe fitting,joint or pipe in the area affected by the fitting shall not fail asdefined in Test Method D1598, when tested in accordance withF1948 05 (2011)27.5. The fitting or joint meets th
37、is requirement when tested inaccordance with any one of the three conditions (A, B, or C)listed in 7.5.7. Test Methods7.1 GeneralThe test methods in this specification covermechanical joint designs. Test methods that are applicable fromother specifications are referenced in the paragraph pertainingt
38、o that particular test.7.1.1 ConditioningUnless otherwise specified, conditionthe specimens (pipe and fittings) prior to joining 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 spec
39、ified.7.1.3 Test SpecimensTest joints shall be prepared with theappropriate size thermoplastic pipe, complying with the dimen-sional requirements of Specification D2513, in accordancewith the manufacturers joining procedures.7.1.4 Precautions and Safety ConsiderationsIt is stronglyrecommended that l
40、iquid be used as the pressurizing fluid whentesting systems that may fail in a brittle manner (specificallyPVC systems). If 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 p
41、ull-out during testing.7.2 Tensile Strength Test:7.2.1 The test pipes, for sizes below NPS 4, shall beprepared so that the 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 abov
42、e, shall be prepared so that the minimum length ofunreinforced pipe from a joint being tested is equal to threetimes the nominal 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 ofu
43、nreinforced pipe (as stated above) exists on at least one joint.7.2.2 The apparatus and report shall be as specified in TestMethod D638. 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 s
44、ample shall constitute failure of thetest.7.3 Temperature Cycling Test:7.3.1 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 6.1.1.7.3.2 Leak test specimens at ambient temperature at 76 3psig (48.
45、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 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.
46、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 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 us
47、ed for leak testing, and the design of thejoint is such that air can be trapped within the joint assembly, allowadequate time 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
48、 accordance with Test Method F1588 for a minimumof 1000 h at an internal pressure between 4 psig (27.6 kPa) andthe pipe MAOP.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 and
49、six of the largest nominal pipe sizes of each mechanical jointdesign and assembled as outlined in 6.1.1.7.5.2 The apparatus and report shall be as specified in TestMethod D1598.7.5.3 The assembled joints shall be tested in accordancewith Test Method D1598 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 sh
