1、Designation:F194805 (Reapproved 2011) Designation: F1948 12An 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 im
2、mediately following 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. Scope*1.1 T
3、his specification covers requirements and test methods for the qualification of metallic mechanical fittings for use withoutside diameter controlled thermoplastic gas distribution pipe and tubing as specified in Specification D2513.1.2 The test methods described are not intended to be routine qualit
4、y control tests.1.3 This specification covers the types of mechanical fittings described in 3.3.1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information only and are not conside
5、red standard.1.5 The following safety hazards caveat pertains only to the test method portion, Section 7, of this specification. This standardmay involve hazardous material, operations and equipment. This standard does not purport to address all of the safety concerns,if any, associated with its use
6、. It is the responsibility of the user of this standard to establish appropriate safety and health practicesand determine the applicability of regulatory limitations prior to use.1.6 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnote
7、s(excluding those in tables and figures), shall not be considered as 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 Pipe Under Constant Internal PressureD1600 Terminology for
8、Abbreviated Terms Relating to PlasticsD2513 Specification for Polyethylene (PE) Gas Pressure Pipe, Tubing, and FittingsF412 Terminology Relating to Plastic Piping SystemsF1588 Test Method for Constant Tensile Load Joint Test (CTLJT) Test Method for Constant Tensile Load Joint Test (CTLJT)F2897 Speci
9、fication for Tracking and Traceability Encoding System of Natural Gas Distribution Components (Pipe, Tubing,Fittings, Valves, and Appurtenances)2.2 ASME Standard:ASME B 31.8 Gas Transmission and Distribution Piping Systems32.3 Federal Specification:OPS Part 192 Title 49, Code of Federal Regulations4
10、2.4 Other Document:PPI TR-4 Recommended Hydrostatic Strengths and Design Stresses for Thermoplastic Pipe and Fitting Compounds53. Terminology3.1 Definitions are in accordance with Definitions F412 unless otherwise specified. Abbreviations are in accordance withAbbreviations D1600 unless otherwise sp
11、ecified.1This specification is under the jurisdiction of ASTM Committee F17 on Plastic Piping Systems , and is the direct responsibility of Subcommittee F17.60 on Gas.Current edition approved Feb.April 1, 2011.2012. Published March 2011.May 2012. Originally published in 1999. Last previous edition a
12、pproved in 20052011 asE194805.F194805(2011). DOI: 10.1520/F1948-05R11.10.1520/F1948-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summa
13、ry page on the ASTM website.3Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.4Available from the Office of Pipeline Safety, Research and Special Programs Administration, U.S. Department of T
14、ransportation, 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.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication
15、 of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be conside
16、red the official document.*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.1 The gas industry terminology used in this specification is in accordance with ASME/ANSI
17、B31.8 or United States CFR49 Part 192 unless otherwise indicated.3.1.2 The term “pipe” used herein refers to both pipe and tubing unless specifically stated otherwise. The term “fitting” refersto a mechanical connecting device as described in 3.2.5 and 3.2.7.3.2 Definitions:3.2.1 Category 1 mechanic
18、al fitting, nfitting for assembling pipe, which includes a compression zone(s) to provide forpressure integrity, leak tightness, and resistance to end loads sufficient to cause no less than 25 % elongation of the piping, asdescribed in this standard.3.2.2 Category 2 mechanical fitting, nfitting for
19、assembling pipe, which includes a compression zone(s) to provide forpressure integrity and leak tightness; Category 2 fittings do not provide for resistance to end loads.3.2.3 Category 3 mechanical fitting, nfitting for assembling pipe, which includes a compression zone(s) for pressure integrity,lea
20、k tightness, and resistance to end loads; the nominal size of the fitting shall be 4 and larger in diameter.3.2.3.1 DiscussionResistance to end loads shall be equal to or greater than the maximum thermal stress that would beproduced by a temperature change of 100F (55C) (for formula, see Annex A1).3
21、.2.4 joint, nthe location at which two or more pieces of pipe, or a pipe and a fitting, are connected (an installed couplinghas two joints).3.2.5 joint, mechanical, na connection between piping components employing physical force to develop a seal or producealignment.3.2.6 maximum allowable operatin
22、g pressure, MAOP, nof the fuel gas piping system, in psig, as determined in accordancewith US DOT CFR, Title 49, Part 192.121, and as represented in the following:MAOP5P52 3 S/R1!xf (1)F1948-12_1where:S = the pipe materials HDB as published in PPI TR 4,R = the pipes dimension ratio determined by div
23、iding the pipes specified nominal outside diameter by the pipes specifiednominal wall thickness, andf = design (derating) factor for thermoplastic fuel gas piping as set by the authority having jurisdiction. In the United States,the design factor is cited in CFR, Title 49, Part 192.121.3.2.7 mechani
24、cal fitting, nfitting for making a mechanical joint to provide for pressure integrity, leak tightness, and,depending on category, as defined in this standard, resistance to end loads.3.3 Types of Mechanical Fittings:3.3.1 clamped insert fitting, nmechanical fitting used to make a mechanical joint th
25、at utilizes external clamps, or othermechanical devices, to form a pressure seal between the reinforcing tubular stiffener and the surface of the pipe.3.3.2 compression fitting, nmechanical fitting used to make a mechanical joint by compressing either externally, internally,or radially to form a pre
26、ssure seal between the fitting and the surface of the pipe.3.3.3 compression gasket fitting, nmechanical fitting used to make a mechanical joint that utilizes a compression nut,tightening ring, bolts, or any other device to compress gasketing onto the surface of the pipe to form a pressure seal.3.3.
27、4 stab-type fitting, nmechanical fitting used to make a mechanical joint in which a seal is achieved by radial compressionof a gasket between the outside diameter (OD) of the pipe and the inside diameter (ID) of the fitting.4. Material4.1 The physical properties of each material used to produce the
28、fitting shall be available from the fitting manufacturer uponrequest.4.2 Specifications outlining the physical and chemical properties of all fitting materials shall be available from the fittingmanufacturer upon request.NOTE 1Materials in long-term contact with natural gas of line quality and LP ga
29、s vapor should be demonstrated to not adversely effect theperformance of the fitting.NOTE 2Materials should have a demonstrated resistance to environmental stress cracking when exposed, under stress, to chemical compoundsencountered in or external to gas piping systems, and a demonstrated resistance
30、 to bacteriological decomposition. Such compounds include, but are notlimited to, ice thawing chemicals, fertilizers, insecticides, herbicides, leak detection fluids, acids, bases and antifreeze solutions used to thaw frozen lines.5. Dimensions5.1 The dimensions and tolerances shall be determined by
31、 the manufacturer.6. Qualification Requirements6.1 GeneralUnless otherwise specified, each nominal size of fitting shall be tested. Testing the fitting with the thickest wallpipe for which the fitting is designed qualifies that type of fitting for use with pipe of lesser wall thickness.6.1.1 Mechani
32、cal joint qualification shall be performed on assembled joints using the fitting manufacturers joining procedure.All mechanical fittings offered by the manufacturer shall be capable of meeting the requirements of this standard when connectingF1948 122thermoplastic piping materials complying with Spe
33、cification D2513. It is not the intent of this standard to require the testing ofall 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 an internal pipe reinforcing tubular stiffener that extends at least und
34、erthe seal and gripping device (where used).6.2 Performance Requirements:6.2.1 Tensile StrengthThe pipe joint shall accommodate the tensile loads, when tested in accordance with 7.2.6.2.1.1 Category 1The joint shall provide resistance to a force on the pipe joint equal to or greater than that which
35、will causeno less than 25 % elongation of the pipe, or which causes the pipe to fail outside the joint area when tested in accordance with7.2.6.2.1.2 Category 2Joint design that only provides a seal. A mechanical joint designed for this category excludes anyprovisions in the design of the joint to r
36、esist axial pullout forces; therefore, tensile tests are not required.6.2.1.3 Category 3Joint of nominal pipe size 4 and larger in diameter shall provide resistance to a force on the pipe joint equalto or greater than the maximum thermal stress that would be produced by a temperature change of 100F
37、(55C) (for formula, seeAnnex A1).NOTE 3Category 3 has a manufacturers rated pipe end restraint less than the value required to yield the pipe as outlined in 6.2.1.1 (Category 1).6.2.1.4 Joint restraint capabilities less than as defined in 6.2.2.1 and 6.2.2.3 shall constitute failure of the test.6.2.
38、2 Temperature Cycling TestThe mechanical joint shall provide a pressure seal after 10 cycles of the temperature cyclingtest when tested in accordance with 7.3.6.2.3 Constant Tensile Load TestThe joint shall not fail by leakage or pullout when loaded to an axial tensile stress of 1320psi (9101 kPa) a
39、nd 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 as definedin Test Method D1598, when tested in accordance with 7.5. The fitting or joint meets this requirement when tested in accordancewith any
40、one of the three conditions (A, B, or C) listed in 7.5.7. Test Methods7.1 GeneralThe test methods in this specification cover mechanical joint designs. Test methods that are applicable from otherspecifications are referenced in the paragraph pertaining to that particular test.7.1.1 ConditioningUnles
41、s otherwise specified, condition the specimens (pipe and fittings) prior to joining at 73.4 6 3.6F (236 2C) for not less than 16 h.7.1.2 Test ConditionsConduct the testing at the standard laboratory temperature of 73.4 6 3.6F (23 6 2C) unless otherwisespecified.7.1.3 Test SpecimensTest joints shall
42、be prepared with the appropriate size thermoplastic pipe, complying with thedimensional requirements of Specification D2513, in accordance with the manufacturers joining procedures.7.1.4 Precautions and Safety ConsiderationsIt is strongly recommended that liquid be used as the pressurizing fluid whe
43、ntesting systems that may fail in a brittle manner (specifically PVC systems). If that is not possible, the test specimens must beplaced in a strong chamber at all times when pressurized. Also, fittings as specified in 6.2.1.2 should be restrained to preventpull-out during testing.7.2 Tensile Streng
44、th Test:7.2.1 The test pipes, for sizes below NPS 4, shall be prepared so that the minimum length of unreinforced pipe from a joint beingtested is equal to five times the nominal outside diameter of the pipe being tested. The test pipes, for sizes NPS 4 and above, shallbe prepared so that the minimu
45、m length of unreinforced pipe from a joint being tested is equal to three times the nominal outsidediameter of the pipe being tested, but in no case less than 12 in. (304 mm). It is permissible to test multiple joints together, providedthat the minimum length of unreinforced pipe (as stated above) e
46、xists on at least one joint.7.2.2 The apparatus and report shall be as specified in Test Method D638. Test six joints.7.2.3 The test shall be conducted at 73.4F 6 3.6F (23C 6 2C).7.2.4 The speed of the testing shall be 0.2 in. (5 mm)/min.6 25 %.7.2.5 Failure of any sample shall constitute failure of
47、 the test.7.3 Temperature Cycling Test:7.3.1 The test shall be conducted on six of the smallest and six of the largest nominal pipe sizes of each mechanical joint designand assembled as outlined in 6.1.1.7.3.2 Leak test specimens at ambient temperature at 76 3 psig (48.3 6 20.7 kPa) and a minimum of
48、 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 140F6 3.6F (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 spe
49、cimens of each size at 7 6 3 psig (48.3 6 20.7 kPa) and the remaining 50 % of each size at1.5 3 MAOP of the piping material and SDR for which the fittings are designed to be used. Leak test first at 140 6 3.6F (606 2C) and then at 20 6 3.6F (296 2C).NOTE 4If immersion is used for leak testing, and the design of the joint is such that air can be trapped within the joint assembly, allow adequate timeF1948 123for all air trapped within the joint to escape prior to observing for leaks.7.4 Constant Tensile Load Joint
