1、Designation: F2785 12 An American National StandardStandard Specification forPolyamide 12 Gas Pressure Pipe, Tubing, and Fittings1This standard is issued under the fixed designation F2785; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, 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 characterization of polyamide 12 pip
3、e, tubing, andfittings for use in fuel gas mains and services for direct burialand reliner applications. The pipe and fittings covered by thisspecification are intended for use in the distribution of naturalgas.1.1.1 This specification does not cover threaded pipe. Ge-neric fusion guidelines are giv
4、en in Appendix X1. Designconsiderations are discussed in Appendix X2. In-plant qualitycontrol programs are specified in Annex A1.1.2 The text of this specification references notes, footnotes,and appendixes which provide explanatory material. Thesenotes and footnotes (excluding those in tables and f
5、igures) shallnot be considered as requirements of the specification.1.3 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.1.4 This standard
6、 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-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1Pipe and fittings utilizin
7、g heat fusion joining techniquesproduced from compounds meeting the requirements of Group 3, Class 2,and Grade 3 (PA323 or PA11) are intended for use with pipe manufacturedfrom compounds meeting the requirements of Group 3, class 2 and Grade3. Pipe and fittings utilizing heat fusion joining techniqu
8、es produced fromcompounds meeting the requirements of Group 4, Class 2 and Grade 3 (PA423 or PA12) are intended for use with pipe manufactured from com-pounds meeting the requirements of Group 4, Class 2 and Grade 3. As perthe recommendations of the respective resin manufacturers, no crossfusion bet
9、ween PA 323 (PA11) and PA 423 (PA12) compounds ispermitted.2. Referenced Documents2.1 ASTM Standards:2D543 Practices for Evaluating the Resistance of Plastics toChemical ReagentsD618 Practice for Conditioning Plastics for TestingD648 Test Method for Deflection Temperature of PlasticsUnder Flexural L
10、oad in the Edgewise PositionD638 Test Method for Tensile Properties of PlasticsD789 Test Methods for Determination of Solution Viscosi-ties of Polyamide (PA)D792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD1598 Test Method for Time-to-Failure of Plas
11、tic PipeUnder Constant Internal PressureD1599 Test Method for Resistance to Short-Time HydraulicPressure of Plastic Pipe, Tubing, and FittingsD1898 Practice for Sampling of Plastics (Withdrawn 1998)3D1600 Terminology forAbbreviated Terms Relating to Plas-ticsD2122 Test Method for Determining Dimensi
12、ons of Ther-moplastic Pipe and FittingsD2774 Practice for Underground Installation of Thermoplas-tic Pressure PipingD2290 Test Method for Apparent Hoop Tensile Strength ofPlastic or Reinforced Plastic PipeD2837 Test Method for Obtaining Hydrostatic Design Basisfor Thermoplastic Pipe Materials or Pre
13、ssure Design Basisfor Thermoplastic Pipe ProductsD6779 Classification System for and Basis of Specificationfor Polyamide Molding and Extrusion Materials (PA)F412 Terminology Relating to Plastic Piping SystemsF1025 Guide for Selection and Use of Full-Encirclement-Type Band Clamps for Reinforcement or
14、 Repair of Punc-tures or Holes in Polyethylene Gas Pressure Pipe1This test method is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F17.60 on Gas.Current edition approved Aug. 1, 2012. Published September 2012. Originallyapprove
15、d in 2009 as F278509. Last previous edition approved in 2010 asF278510a. DOI: 10.1520/F2785-12.2For 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 the standards Documen
16、t Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis
17、 international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TB
18、T) Committee.1F1473 Test Method for Notch Tensile Test to Measure theResistance to Slow Crack Growth of Polyethylene Pipesand ResinsF1733 Specification for Butt Heat Fusion Polyamide(PA)Plastic Fitting for Polyamide(PA) Plastic Pipe and TubingF1973 Specification for Factory Assembled Anodeless Ris-e
19、rs and Transition Fittings in Polyethylene (PE) andPolyamide 11 (PA11) and Polyamide 12 (PA12) Fuel GasDistribution SystemsF2138 Specification for Excess Flow Valves for Natural GasServiceF2145 Specification for Polyamide 11 (PA 11) and Poly-amide 12 (PA12) Mechanical Fittings for Use on OutsideDiam
20、eter Controlled Polyamide 11 and Polyamide 12 Pipeand TubingF2767 Specification for Electrofusion Type Polyamide-12Fittings for Outside Diameter Controlled Polyamide-12Pipe and Tubing for Gas DistributionF2897 Specification for Tracking and Traceability EncodingSystem of Natural Gas Distribution Com
21、ponents (Pipe,Tubing, Fittings, Valves, and Appurtenances)2.2 ANSI Standards:4B 16.40 Manually Operated Thermoplastic Gas Shutoffs andValves in Gas Distribution SystemsB 31.8 Gas Transmission and Distribution Piping Systems2.3 Federal Specifications:5Fed. Std. No. 123 Marking for Shipment (Civil Age
22、ncies)OPS Part 192 Title 49 ,Title 49 Code of Federal Regulations2.4 Military Standards:6MIL-STD-129 Marking for Shipment and StorageMIL-STD-1235 (ORD) Single- and Multi-Level Continu-ous Sampling Procedures and Tables for Inspection byAttributes2.5 ISO Standards:6307 Plastics - Polyamides - Determi
23、nation of viscositynumber3146 Plastics - Determination of melting behaviour (melt-ing temperature or melting range) of semi-crystallinepolymers by capillary tube and polarizing-microscopemethods1183 Plastics - Methods for determining the density ofnon-cellular plastics - Part 1: Immersion method, li
24、quidpyknometer method and titration method5271 Plastics - Determination of tensile properties - Part1: General principles5272 Plastics - Determination of tensile properties - Part2: Test conditions for moulding and extrusion plastics178 Plastics - Determination of flexural properties179 Plastics - D
25、etermination of Charpy impact properties -Part 1: Non-instrumented impact test751 Plastics - Determination of temperature of deflectionunder load - Part 1: General test method752 Plastics - Determination of temperature of deflectionunder load - Part 2: Plastics and eboniteISO 22621 Part 1 Plastics p
26、iping systems for the supply ofgaseous fuels for maximum operating pressure up to andincluding 2 MPa (20 bar) Polyamide (PA) : General2.6 Plastic Pipe Institute:7PPI TR3 Policies and Procedures for Developing Hydro-static Design Basis (HDB), Pressure Design Basis (PDB),Strength Design Basis (SDB), a
27、nd Minimum RequiredStrength (MRS) Ratings for Thermoplastic Piping Mate-rials or PipePPI TR4 Hydrostatic Design Bases and Maximum Recom-mended Hydrostatic Design Stresses for ThermoplasticPiping MaterialsPPI TN7 Nature of Hydrostatic Stress Rupture Curves2.7 Other Standards:8National Fire Protection
28、Association: NFPA58 , Storage andHandling Liquefied Petroleum Gases3. Terminology3.1 DefinitionsDefinitions are in accordance with Termi-nology F412, and abbreviations are in accordance with Termi-nology D1600, unless otherwise specified.3.2 The gas industry terminology used in this specificationis
29、in accordance with ANSI B31.8 or CFR OPS Part 192 Title49, unless otherwise indicated.3.3 The term pipe used herein refers to both pipe and tubingunless specifically stated otherwise.3.4 Definitions of Terms Specific to This Standard:3.4.1 re-rounding equipment, nequipment used to reformthe pipe and
30、 permanently reduce ovality to 5% or less.3.4.2 rounding equipment, nequipment, devices, clamps,and so forth, used to temporarily hold the pipe round whileout-of-roundness measurements are made, or a joining proce-dure (heat fusion, electrofusion, or mechanical) is performed.3.4.3 standard thermopla
31、stic material designated code,nthe pipe material designation code shall consist of theabbreviation for the polyamide (PA) followed by Arabicnumerals which describe the short term properties in accor-dance with Classification D6779, the hydrostatic design stressfor water at 73.4F (23C) in units of 10
32、0 psi with any decimalfigures dropped. Where the hydrostatic design stress codecontains less than two figures, a zero is used before the number.Thus, a complete material designation code shall consist of twoletters and five figures for polyamide pipe materials. Forexample, PA 42316 is a grade of pol
33、yamide 12 with a 1600 psidesign stress for water at 73.4F (23C). The hydrostatic designstresses for gas are not used in this designation code.3.4.4 thermoplastic pipe dimension ratio (DR), nthe ratioof pipe diameter to wall thickness. It is calculated by dividing4Available from American National Sta
34、ndards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/www.dodssp.daps.mil.6Available from International Organization for Standardi
35、zation (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.7Available from Plastics Pipe Institute (PPI), 105 Decker Court, Suite 825,Irving, TX 75062, http:/www.plasticpipe.org.8Available from National Fire Protection Association (NFPA), 1 Batterymarch
36、Park, Quincy, MA 02169-7471, http:/www.nfpa.org.F2785 122the specified outside diameter of the pipe, in inches, by theminimum specified wall thickness, in inches. The standarddimension ratio (SDR) is a common numbering system whichis derived from the ANSI preferred number series R 10.3.4.5 toe-in, n
37、a small reduction of the outside diameter atthe cut end of a length of thermoplastic pipe.4. Requirements for Materials4.1 GeneralThe polyamide material used to make pipeand fittings shall be virgin or reworked material (see 4.5 ) andshall have a Plastics Pipe Institute (PPI) long-term hydrostaticde
38、sign stress and hydrostatic design basis rating as determinedper PPI TR3 and PPI TR4.4.2 ClassificationPolyamide materials suitable for use inthe manufacturing of pipe and fittings under this specificationshall be classified in accordance with Classification D6779,asshown in Table 1.4.3 Short- and L
39、ong-Term PropertiesPolyamide pipe andfittings shall be made from a PA material which also satisfiesthe combinations of short- and long-term property require-ments shown in Table 2.4.4 Resistance to Rapid Crack Propagation (RCP) forMaterialslThe material classification (formulation) used inthe manufa
40、cture of pipe and fittings under this specificationshall be tested for resistance to failure by RCP in accordancewith 6.7. The data obtained shall be made available uponrequest without limitations on disclosure, and shall not subse-quently be subject to disclosure limitations when used byothers. The
41、 values obtained are applicable to all pipes with thewall thickness of the pipe tested and all thinner wall pipes.4.5 Rework MaterialClean rework material of the samecommercial designation, generated from the manufacturersown pipe and fitting production shall not be used unless thepipe and fittings
42、produced meet all the requirements of thisspecification.4.6 DocumentationA documentation system to allow fortraceability of raw materials including percentage and materialclassification (or designation, if applicable) of rework materialsused in the manufacture of the pipe product meeting therequirem
43、ents of this specification shall exist and be supplied tothe purchaser, if requested.5. Requirements for Pipe and Fittings5.1 GeneralPipe shall be supplied in either coils orstraight lengths.Any pipe supplied in coils must meet the samerequirements before and after coiling.5.2 WorkmanshipThe pipe an
44、d fittings shall be homoge-neous throughout and free of visible cracks, holes, foreigninclusion, blisters, and dents, or other injurious defects. Thepipe and fittings shall be as uniform as commercially practi-cable in color, opacity, density, and other physical properties.5.3 Pipe and Tubing Dimens
45、ions and Tolerances:5.3.1 DimensionThe dimensions shall be specified bywall thickness and outside diameter.5.3.1.1 DiametersThe outside diameter shall meet therequirements given in Table 3 or Table 4 when measured inaccordance with 6.5.5.3.1.2 Toe-InWhen measured in accordance with 6.5.1.1,the outsi
46、de diameter at the cut end of the pipe shall not be morethan 1.5 % smaller than the undistorted outside diameter.Measurement of the undistorted outside diameter shall be madeno closer than 1.5 pipe diameters or 11.8 in. (300 mm),whichever distance is less, from the cut end of the pipe.Undistorted ou
47、tside diameter shall meet the requirements ofTable 3 or Table 4.5.3.1.3 Wall ThicknessThe wall thickness shall be asspecified in Table 4 or Table 5 when measured in accordancewith 6.5.1.2. The minimum wall thickness at any point ofmeasurement shall be not less than the minimum wall thicknessspecifie
48、d in Table 4 or Table 5.TABLE 1 Classification D6779Classification ASTM Test Method ISO Test Method DesignationPA4 (group)2 (class)3 (grade)PolyamidePA 12Heat stabilizedViscosity number, min. D789 ISO 307 211Specific gravity D792 ISO 1183 1.001.06Tensile strength, min,MPaD638 ISO 5271 andISO 527235T
49、ensile Modulus, min,MPaISO 5271 andISO 52721000Charpy impact resistance,minISO 179 25Deflection temperature,at 1.82 Mpa, min CD648 ISO 751 andISO 75235TABLE 2 Short and Long Term Property RequirementsPA MaterialDesignation CodeShort-Term inAccordance withD6779Long-Term inAccordance withD2837PA42316 PA423 HDB of 3150 psifor 73F (23C)F2785 1235.3.1.4 Wall Thickness Eccentricity Range The wall thick-ness eccentricity range shall be within 12 % when measured inaccordance with 6.5.1.3.5.3.1.5 OvalityThe ovality (cross secti
