1、Designation: F1948 15Standard 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 the designation indicates the year oforiginal a
2、doption 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. Scope*1.1 This specification covers requirements and test methodsfor the quali
3、fication 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 specification covers the types of mechanical
4、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 following safety hazards caveat pertains only to the
5、test 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 standard to establish appro-p
6、riate 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), shall not be consideredas requir
7、ements 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 forAbbreviated Terms Relating to Plas-ticsD2513 Specification for Thermoplastic
8、Gas Pressure Pipe,Tubing, and FittingsE515 Practice for Leaks Using Bubble Emission TechniquesF412 Terminology Relating to Plastic Piping SystemsF1588 Test Method for Constant Tensile Load Joint Test(CTLJT)F2785 Specification for Polyamide 12 Gas Pressure Pipe,Tubing, and FittingsF2897 Specification
9、 for Tracking and Traceability EncodingSystem of Natural Gas Distribution Components (Pipe,Tubing, Fittings, Valves, and Appurtenances)F2945 Specification for Polyamide 11 Gas Pressure Pipe,Tubing, and Fittings2.2 ASME Standard:ASME B 31.8 Gas Transmission and Distribution PipingSystems32.3 Federal
10、Specification: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. Abbreviation
11、s are in accordancewith 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
12、specifically stated otherwise. The term “fitting”refers to a mechanical connecting device as described in 3.2.5and 3.2.7.3.2 Definitions:1This specification is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems, and is the direct responsibility of Subcommittee F17.60 on Gas.Curren
13、t edition approved Dec. 1, 2015. Published February 2016. Originallypublished in 1999. Last previous edition approved in 2012 as F194812. DOI:10.1520/F1948-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of
14、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 Safet
15、y, 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.*A Summary of Changes section appears at the e
16、nd of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.1 Category 1 mechanical fitting, nfitting for assem-bling pipe, which includes a compression zone(s) to providefor pressure integrity, leak tightness, and resistan
17、ce to endloads 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
18、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 end loads; thenominal size of the fitting shall be 4 and larger in diameter.3.2.3.1 DiscussionResistance to en
19、d 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 two or more pieces ofpipe, or a pipe and a fitting, are connected (an installedcoupling has two joints).3.2.5
20、 joint, mechanical, na connection between pipingcomponents employing physical force to develop a seal orproduce alignment.3.2.6 maximum allowable operating pressure, MAOP, nofthe fuel gas piping system, in psig, as determined in accordancewith US DOT CFR, Title 49, Part 192.121, and as representedin
21、 the following:MAOP 5 P 5 2 3 S/R 2 1!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 by the pipesspecified nominal wall thickness, andf = design (derating) factor for thermoplastic fuel
22、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 provide for pressure integrity, leak tightness, and,depending on category, as defined in this standa
23、rd, 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, to form a pressure seal between thereinforcing tubular stiffener and the surface of the pipe.3.3.2 c
24、ompression 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.3.3.3 compression gasket fitting, nmechanical fitting usedto make a mechanical joint that utilizes a
25、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 amechanical joint in which a seal is achieved by radial com-pression of a gasket between; the outside diam
26、eter (OD) of thepipe and the inside diameter (ID) of the fitting; the insidediameter (ID) of the pipe with the insert stiffener; or both.4. Material4.1 The physical properties of each material used to producethe fitting shall be available from the fitting manufacturer uponrequest.4.2 Specifications
27、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 theperformance of the fitting.NOT
28、E 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, but are not limited to, ic
29、e thawing chemicals, fertilizers,insecticides, 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 GeneralUnless otherwise specified, e
30、ach 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 joints using the fitting manufactu
31、rers joining pro-cedure. All mechanical fittings offered by the manufacturershall be capable of meeting the requirements of this standardwhen:6.1.1.1 Connecting thermoplastic gas piping complyingwith applicable ASTM thermoplastic gas piping standards, aslisted in Section 2, Referenced Documents, eit
32、her same to same(for example, PE to PE) or transitioning (for example, PE toPA).6.1.1.2 Transitioning between thermoplastic gas pipingcomplying with applicable ASTM thermoplastic gas pipingstandards, in Section 2, Referenced Documents, and metalpiping. It is not the intent of this standard to requir
33、e the testingof all fitting configurations (that is, tee, ells, etc.) but eachfitting 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). Exception:When
34、 the fitting is used to transition from plastic to metal, onlythe plastic end of the fitting is required to have a stiffeneremployed.6.1.3 In the case of fittings designed to transition betweendifferent thermoplastic materials, between different wall thick-nesses (SDRs), or different diameters of th
35、e same thermoplas-tic material, the pipe requiring the lowest force to elongate toF1948 152yield shall fail before any joint fails. For example, whentransitioning between PE and PA of the same wall thickness(same DR) and diameter, failure of the PE before the joint fails,qualifies the fitting in thi
36、s transition scenario.Another exampleis a fitting used to transition between 1CTS PE and12 CTS PEpiping, of the same DR, qualifies if the12 CTS tubing failsbefore the joint fails.6.1.4 In the case of fittings designed to transition betweenmetallic piping and thermoplastic piping, the fitting shall b
37、equalified as Category 1 under this standard only if the jointbetween the fitting and the metallic piping has been tested toprovide axial tensile restraint strength of 1.5 times the tensilestrength at yield of the thermoplastic piping joined to theopposite end.6.1.4.1 The metallic piping shall not p
38、ull out of the fittingwhen tested to the following pull-out forces and tested inaccordance with 7.2.(1) For PE 3770 psi(2) For PA11 8700 psi(3) For PA12 7614 psi6.2 Performance Requirements:6.2.1 Tensile StrengthThe fitting shall provide a thermo-plastic pipe joint design capable of accommodating th
39、e follow-ing tensile loads, when tested in accordance with 7.2.6.2.1.1 Category 1A fitting that, when properly installedand meeting the qualification requirements of 6.1.1, 6.1.2 and6.1.3, shall provide for joints in thermoplastic piping that resistpull-out to a force on the thermoplastic pipe equal
40、 to or greaterthan that which will cause no less than 25% elongation of theplastic pipe, or which causes the plastic pipe to fail outside thejoint area when tested in accordance with 7.2. Furthermore, afitting designed to transition between metallic piping andthermoplastic piping that, when properly
41、 installed, shall meetthe qualification requirements of 6.1.4 when tested in accor-dance with 7.2.6.2.1.2 Category 2Fitting that, when properly installed,creates a joint that provides only a seal. A mechanical jointdesigned for this category excludes any provisions in thedesign of the joint to resis
42、t axial pullout forces; therefore,tensile tests are not required.6.2.1.3 Category 3Fittings of nominal pipe size 4 andlarger in diameter that, when properly installed provides apull-out resistance to a force on the thermoplastic pipe jointequal to or greater than the maximum thermalstress that would
43、be produced 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 Fitting restraint capabilities less than as defined in6.2.1.1 and 6.2.1.3
44、 shall 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 Test (CTLIT)Pull out of thepipe or leakage before, during or after testi
45、ng in accordancewith 7.4, shall constitute failure of the test.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 with7.5. The fitting or joint meets this requirement when t
46、ested inaccordance with any one of the three conditions (A, B, or C)for PE (polyethylene) piping, or any of the two conditions (Dor E) for PA (polyamide) piping, as listed in Table 1 ElevatedTemperature Sustained Pressure Test Conditions. To qualifyfittings designed and used for transitioning betwee
47、n differentthermoplastic piping materials, the hoop stress condition of thematerial with the lowest HDB shall be used.7. Test Methods7.1 GeneralThe test methods in this specification covermechanical joint designs.Test methods that are applicable fromother specifications are referenced in the paragra
48、ph pertainingto 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) unless
49、otherwise specified.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 liquid 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
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