1、Designation: F876 101F876 13 An American National StandardStandard Specification forCrosslinked Polyethylene (PEX) Tubing1This standard is issued under the fixed designation F876; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the
2、 year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1 NOTE3.2.7.2 was editorially corrected in October 2011.1. Scope*1.1 This specification covers crosslinked polyethylene (PEX)
3、 tubing that incorporates an optional polymeric inner, middle orouter layer and that is outside diameter controlled, made in nominal SDR9 tubing dimension ratios except were noted, and pressurerated for water at three temperatures (see Appendix X1). Included are requirements and test methods for mat
4、erial, workmanship,dimensions, burst pressure, hydrostatic sustained pressure, excessive temperature pressure, excessive temperature-pressure,environmental stress cracking, stabilizer functionality, bent-tube hydrostatic pressure, oxidative stability in potable chlorinatedwater, and degree of crossl
5、inking. Requirements for tubing markings are also given.1.2 The text of this specification references notes, footnotes, and appendixes which provide explanatory material. These notesand footnotes (excluding those in tables and figures) shall not be considered as requirements of the specification.1.3
6、 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 considered standard.1.4 The following safety hazards caveat pertains only to the test methods portion, Sec
7、tion 7, of this specification:This standarddoes not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of thisstandard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prio
8、r to use.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD792 Test Methods for Density and Specific Gravity (Relative Density) of Plastics by DisplacementD1505 Test Method for Density of Plastics by the Density-Gradient TechniqueD1598 Test Method for Tim
9、e-to-Failure of Plastic Pipe Under Constant Internal PressureD1599 Test Method for Resistance to Short-Time Hydraulic Pressure of Plastic Pipe, Tubing, and FittingsD1600 Terminology for Abbreviated Terms Relating to PlasticsD1898 Practice for Sampling of Plastics (Withdrawn 1998)3D2122 Test Method f
10、or Determining Dimensions of Thermoplastic Pipe and FittingsD2765 Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene PlasticsD2837 Test Method for Obtaining Hydrostatic Design Basis for Thermoplastic Pipe Materials or Pressure Design Basis forThermoplastic Pipe Pro
11、ductsD3895 Test Method for Oxidative-Induction Time of Polyolefins by Differential Scanning CalorimetryF412 Terminology Relating to Plastic Piping SystemsF1281 Specification for Crosslinked Polyethylene/Aluminum/Crosslinked Polyethylene (PEX-AL-PEX) Pressure PipeF2023 Test Method for Evaluating the
12、Oxidative Resistance of Crosslinked Polyethylene (PEX) Tubing and Systems to HotChlorinated WaterF2657 Test Method for Outdoor Weathering Exposure of Crosslinked Polyethylene (PEX) Tubing1 This specification is under the jurisdiction of ASTM Committee F17 on Plastic Piping Systems and is the direct
13、responsibility of Subcommittee F17.26 on Olefin BasedPipe.Current edition approved Feb. 1, 2010April 15, 2013. Published March 2010April 2013. Originally approved in 1984. Last previous edition approved 20082010 asF876 08b.F876 0101. DOI: 10.1520/F0876-09E01.10.1520/F0876-13.2 For referencedASTM sta
14、ndards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org
15、.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication 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 ed
16、itions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-29
17、59. United States12.2 ANSI Standard:B36.10 Standards Dimensions of Steel Pipe (IPS)42.3 Federal Standard:FED-STD-123 Marking for Shipment (Civil Agencies)52.4 Military Standard:MIL-STD-129 Marking for Shipment and Storage52.5 NSF Standard:NSF/ANSI 14 for Plastic Piping Components and Related Materia
18、ls62.6 ISO Standards:4ISO 1167 Thermoplastics pipes, fittings and assemblies for the conveyance of fluids - Determination of the resistance to internalpressure - Part 1: General methodISO 13760 Plastics pipes for the conveyance of fluids under pressure - Miners rule - Calculation method for cumulati
19、vedamageISO R 161-1690 Pipes of Plastic Materials for the Transport of Fluids (Outside Diameters and Nominal Pressures) Part 1, MetricSeries2.7 PPI Standard:7PPI TR-4 PPI Listing of Hydrostatic Design Basis (HDB), Strength Design Basis (SDB), Pressure Design Basis (PDB) andMinimum Required Strength
20、(MRS) Ratings for Thermoplastic Piping Materials or Pipe3. Terminology3.1 DefinitionsDefinitions are in accordance with Terminology F412, and abbreviations are in accordance with TerminologyD1600, unless otherwise specified. The abbreviation for crosslinked polyethylene is PEX. Plastic tubing denote
21、s a particulardiameter schedule of plastic pipe in which outside diameter of the tubing is equal to the nominal size plus 18 in. Plastic pipe outsidediameter schedule conforms to ANSI B36.10.3.2 Definitions of Terms Specific to This Standard:3.2.1 crosslinked polyethylene plasticspolyethyleneplastic
22、s prepared by crosslinking (curing) polyethylene compounds. apolyethylene material which has undergone a change in molecular structure using a chemical or a physical process whereby thepolymer chains are chemically linked.4 Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
23、 4th Floor, New York, NY 10036, http:/www.ansi.org.5 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/www.dodssp.daps.mil.6 Available from NSF International, P.O. Box 130140, 789 N. Dixboro Rd., Ann Arbor, MI 48113-
24、0140, http:/www.nsf.org.7 Plastics Pipe Institute (PPI), 105 Decker Court, Suite 825 Irving TX, 75062. http:/www.plasticpipe.orgTABLE 1 Wall Thickness and Tolerances for Nominal PEX SDR 9Plastic TubingANominal Tubing Minimum WallThickness Tolerancein. mm in. mm in. mm18 3 0.047B 1.19B +0.007 +0.1814
25、 7 0.062B 1.57B +0.010 +0.25516 8 0.064 1.63 +0.010 +0.2538 10 0.070B 1.78B +0.010 +0.2512 13 0.070B 1.78B +0.010 +0.2558 16 0.083 2.12 +0.010 +0.2534 19 0.097 2.47 +0.010 +0.251 25 0.125 3.18 +0.013 +0.33114 32 0.153 3.88 +0.015 +0.38112 38 0.181 4.59 +0.019 +0.482 51 0.236 6.00 +0.024 +0.61212 64
26、0.292 7.41 +0.030 +0.763 76 0.347 8.82 +0.033 +0.84312 89 0.403 10.23 +0.035 +0.894 102 0.458 11.64 +0.040 +1.02412 114 0.514 13.05 +0.045 +1.145 127 0.569 14.46 +0.050 +1.276 152 0.681 17.29 +0.060 +1.52A The minimum is the lowest wall thickness of the pipe at any cross section. Themaximum permitte
27、d wall thickness, at any cross section, is the minimum wallthickness plus the stated tolerance. All tolerances are on the plus side of theminimum requirement.B For tubing sizes of 12 in. and below, wall thickness minimums are not functionsof SDR.F876 1323.2.2 hydrostatic design stress (HDS)the estim
28、ated maximum tensile stress the material is capable of withstandingcontinuously with a high degree of certainty that failure of the tube will not occur. This stress is circumferential when internalhydrostatic water pressure is applied. The HDS is equal to the hydrostatic design basis (HDB) times the
29、 design factor (DF) forwater. For this standard, the design factor is equal to 0.50.HDS5HDB3DF5HDB30.50 for this standard!3.2.3 hydrostatic design basis (HDB)one of a series of established stress values (specified in Test Method D2837) for a plasticcompound obtained by categorizing the long-term hyd
30、rostatic strength determined in accordance with Test Method D2837.3.2.3.1 DiscussionA listing of HDB and HDS values are contained in PPI publication PPI TR4.3.2.4 pressure rating (PR)the estimated maximum water pressure the tube is capable of withstanding continuously with a highdegree of certainty
31、that failure of the tube will not occur.3.2.5 relation between dimensions, hydrostatic design stress, and pressure ratingthe following expression, commonly knownas the ISO equation,8 is used in this specification to relate dimensions, hydrostatic design stress, and pressure rating:2S/P 5 DO/t!21 (1)
32、or2S/P 5 R 2 1where:S = hydrostatic design stress, psi (or MPa),P = pressure rating, psi (or MPa),DO = average outside diameter, in. (or mm),t = minimum wall thickness, in. (or mm), andR = standard dimension ratio, SDR.3.2.6 standard dimension ratio (SDR)the ratio of outside diameter to wall thickne
33、ss. For PEX-tubing, it is calculated bydividing the average outside diameter of the tubing in inches or in millimetres by the minimum wall thickness in inches ormillimetres. If the wall thickness calculated by this formula is less than 0.070 in. (1.78 mm) it shall be arbitrarily increased to 0.070in
34、. except for sizes 516 in. and smaller, as specified in Table 1. The SDR values shall be rounded to the nearest 0.5.3.2.7 standard thermoplastic tubing materials designation codeThe tubing material designation code shall consist of theabbreviation for the type of plastic (PEX) followed by four Arabi
35、c digits that describe short-term properties in accordance withapplicable ASTM standards and as shown in Table 2. See Fig. 1.3.2.7.1 DiscussionThe first digit is for chlorine resistance tested in accordance with Test Method F2023.(1) A digit “0” indicates that the PEX tubing either has not been test
36、ed for chlorine resistance or that the PEX tubing does notmeet the minimum requirement for chlorine resistance.(2) A digit “1” indicates the PEX tubing has been tested and meets the F876 requirement for minimum chlorine resistance atthe end use condition of 25% at 140F (60C) and 75% at 73F (23C).(3)
37、 A digit “2” is reserved for future application.8 ISO R161-1690.For example ASTM F876 PEX tubing marked with the material designation code PEX 1106 is a PEX tubing meeting the chlorine resistance requirement for 25% of thetime at 140F and 75% of the time at 73F having a Minimum UV resistance of 1 mo
38、nth and having an HDS for water at 73F of 630psi (HDB of 1250 psi).FIG. 1 Standard Thermoplastic Tubing Materials Designation CodeF876 133(4) Adigit “3” indicates that the PEX tubing has been tested and meets the F876 requirement for minimum chlorine resistanceat end use condition of 50% at 140F and
39、 50% at 73F.(5) A digit “4” is reserved for future application.(6) A digit “5” indicates that the PEX tubing has been tested and meets the requirement for minimum chlorine resistance atend use conditions of 100% of the time at 140F3.2.7.2 DiscussionThe second digit is for demonstrated UV resistance
40、of PEX material when tested in accordance with Test Method F2657. Forpotable water piping, it shall be one of the classification digits listed in Table 2 for the Nominal ExposureTime Period fromTable 1in Test Method F2657 where the decreased average failure time from 10.3 of Test Method F2657 is les
41、s than or equal to 21%. Fornon-potable piping, it shall be one of the classification digits from Table 2 for the Nominal Exposure Time Period from Table 1of Test Method F2657 where the UV-exposed samples meet the requirement of 7.10 Stabilizer Functionality, or alternatively usingthe criteria for po
42、table water piping found in the this clause.3.2.7.3 DiscussionThe 21% pass/fail criteria originates from the statistical analysis of an aggregate of data sets generated using Test Method F2023and represents the mean Lower Predictive Limit (95% two sided) compared to the expected failure times based
43、on three stresslevels at each of three temperatures. Thus, this value represents the limit for statistical differentiation in failure times using TestMethod F2023 at the 95% confidence level (2 sided). This research was conducted for the Plastics Pipe Institute in 2005.9(1) The UV resistance shall b
44、e demonstrated on representative pipe samples for the original validation of pipe made from aparticular PEX material, that material being the combination of PEX resin and its additive system.(2) The last two digits are the hydrostatic design stress for water at 73F (23C) in units of 100 psi with any
45、 decimal figuresdropped. Where the hydrostatic design stress code contains less than two figures, a zero is used before the number. Thus, acomplete material designation code for PEX tubing shall consist of the three letters “PEX” and four digits.4. Tubing Classification4.1 GeneralThis specification
46、covers one PEX tubing material in one standard dimension ratio and having pressure ratingsfor water of three temperatures. The pressure ratings decrease as the temperature is increased.4.2 Standard Thermoplastic Pipe Dimension Ratio (SDR)This specification covers PEX tubing in one standard dimension
47、ratio (SDR 9) for nominal diameters 58 in. and larger, and with a specified wall thickness for smaller diameters. The pressureratings are uniform for all nominal tubing sizes.5. Materials5.1 GeneralCrosslinked polyethylene tubing, meeting the requirements of this specification, are primarily defined
48、 by meansof three criteria, namely, (1) nominal density, (2) degree of crosslinking, and (3) long-term strength tests. There is a strongcorrelation between nominal density and results of short-term strength tests.NOTE 1PEX tubing intended for use in the transport of potable water should be evaluated
49、 and certified as safe for this purpose by a testing agencyacceptable to the local health authority. The evaluation should be in accordance with requirements for chemical extraction, taste, and odor that are noless restrictive than those included in NSF/ANSI 14. The seal or mark of the laboratory making the evaluation should be included on the tubing.5.2 Basic MaterialsPEX tubing shall be made from polyethylene compounds which have been crosslinked by peroxides,Azocompounds, or silane compounds in extrusion, or by e
