ASTM F1281-17(2021)e1

Standard Specification for Crosslinked Polyethylene/Aluminum/Crosslinked Polyethylene (PEX-AL-PEX) Pressure Pipe

ABSTRACT
This specification covers coextruded cross linked polyethylene composite pressure pipe with welded aluminum tube reinforcement between the inner and outer layers. The inner and outer cross linked polyethylene layers are bonded to the aluminum tube by a melt adhesive. Included is a system of nomenclature for the cross linked polyethylene-aluminum cross linked polyethylene (PEX-AL-PEX) pipes, the requirements and test methods for materials, the dimensions of the component layers and finished pipe, adhesion tests, and the burst and sustained pressure performance. Also given are the requirements and methods of marking. The pipe covered by this specification is intended for use in potable water distribution systems for residential and commercial applications, water service, underground irrigation systems, and radiant panel heating systems, baseboard, snow- and ice-melt systems, and gases that are compatible with the composite pipe and fittings. It covers only composite pipes incorporating a welded aluminum tube. The PEX-AL-PEX pipes are classified by the outside diameter. The pipe shall be free of visible cracks, holes, foreign inclusions, blisters, and other known injurious defects. The pipe shall be as uniform as practicable in color, opacity, density, and other physical properties.
SCOPE
1.1 This specification covers a coextruded crosslinked polyethylene composite pressure pipe with a welded aluminum tube reinforcement between the inner and outer layers. The inner and outer crosslinked polyethylene layers are bonded to the aluminum tube by a melt adhesive. Included is a system of nomenclature for the crosslinked polyethylene-aluminum-crosslinked polyethylene (PEX-AL-PEX) pipes, the requirements and test methods for materials, the dimensions of the component layers and finished pipe, adhesion tests, and the burst and sustained pressure performance. Also given are the requirements and methods of marking. The pipe covered by this specification is intended for use in potable water distribution systems for residential and commercial applications, water service, underground irrigation systems, and radient panel heating systems, baseboard, snow- and ice-melt systems, and gases that are compatible with the composite pipe and fittings.  
1.2 This specification covers only composite pipes incorporating a welded aluminum tube. Pipes consisting of metallic layers not welded together are outside the scope of this specification.  
1.3 Specifications for connectors for use with pipe meeting the requirements of this specification are given in Annex A1.  
1.4 This specification excludes polyethylene-aluminum-polyethylene pipes (see Specification F1282).  
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.6 The following precautionary caveat pertains only to the test methods portion, Section 9, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Historical
• Publication Date: 31-Jul-2017
• ICS: 23.040.20 - Plastics pipes
• Technical Committee: F17 - Plastic Piping Systems
• Drafting Committee: F17.11 - Composite

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation: F1281 − 17 (Reapproved 2021) An American National Standard
Standard Specification for
Crosslinked Polyethylene/Aluminum/Crosslinked
Polyethylene (PEX-AL-PEX) Pressure Pipe
This standard is issued under the fixed designation F1281; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—The units in Annex A2 were editorially revised in October 2021.
1. Scope* environmental practices and determine the applicability of
regulatory limitations prior to use.
1.1 This specification covers a coextruded crosslinked poly-
1.7 This international standard was developed in accor-
ethylene composite pressure pipe with a welded aluminum tube
dance with internationally recognized principles on standard-
reinforcement between the inner and outer layers. The inner
ization established in the Decision on Principles for the
and outer crosslinked polyethylene layers are bonded to the
Development of International Standards, Guides and Recom-
aluminum tube by a melt adhesive. Included is a system of
mendations issued by the World Trade Organization Technical
nomenclature for the crosslinked polyethylene-aluminum-
Barriers to Trade (TBT) Committee.
crosslinked polyethylene (PEX-AL-PEX) pipes, the require-
ments and test methods for materials, the dimensions of the
2. Referenced Documents
component layers and finished pipe, adhesion tests, and the
2.1 ASTM Standards:
burst and sustained pressure performance. Also given are the
D618 Practice for Conditioning Plastics for Testing
requirements and methods of marking. The pipe covered by
D883 Terminology Relating to Plastics
this specification is intended for use in potable water distribu-
D1598 Test Method for Time-to-Failure of Plastic Pipe
tion systems for residential and commercial applications, water
Under Constant Internal Pressure
service, underground irrigation systems, and radient panel
D1599 Test Method for Resistance to Short-Time Hydraulic
heating systems, baseboard, snow- and ice-melt systems, and
Pressure of Plastic Pipe, Tubing, and Fittings
gases that are compatible with the composite pipe and fittings.
D1600 Terminology for Abbreviated Terms Relating to Plas-
1.2 This specification covers only composite pipes incorpo-
tics
rating a welded aluminum tube. Pipes consisting of metallic 3
D1898 Practice for Sampling of Plastics (Withdrawn 1998)
layers not welded together are outside the scope of this
D2122 Test Method for Determining Dimensions of Ther-
specification.
moplastic Pipe and Fittings
1.3 Specifications for connectors for use with pipe meeting D2765 Test Methods for Determination of Gel Content and
the requirements of this specification are given in Annex A1. Swell Ratio of Crosslinked Ethylene Plastics
D3350 Specification for Polyethylene Plastics Pipe and Fit-
1.4 This specification excludes polyethylene-aluminum-
tings Materials
polyethylene pipes (see Specification F1282).
E8/E8M Test Methods for Tension Testing of Metallic Ma-
1.5 The values stated in SI units are to be regarded as
terials
standard. The values given in parentheses after SI units are
F412 Terminology Relating to Plastic Piping Systems
provided for information only and are not considered standard.
F1282 Specification for Polyethylene/Aluminum/
1.6 The following precautionary caveat pertains only to the Polyethylene (PE-AL-PE) Composite Pressure Pipe
test methods portion, Section 9, of this specification: This
F1974 Specification for Metal Insert Fittings for
standard does not purport to address all of the safety concerns, Polyethylene/Aluminum/Polyethylene and Crosslinked
if any, associated with its use. It is the responsibility of the user
Polyethylene/Aluminum/Crosslinked Polyethylene Com-
of this standard to establish appropriate safety, health and posite Pressure Pipe
1 2
This specification is under the jurisdiction of ASTM Committee F17 on Plastic For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Piping Systems and is the direct responsibility of Subcommittee F17.11 on contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Composite. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Aug. 1, 2017. Published October 2021. Originally the ASTM website.
approved in 1990. Last previous edition approved in 2017 as F1281 – 17. DOI: The last approved version of this historical standard is referenced on www.ast-
10.1520/F1281-17R21E01. m.org.
*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
´1
F1281 − 17 (2021)
2.2 National Sanitation Foundation Standard: the thickness of the wall of the pipe. The PEX-AL-PEX pipes
Standard No. 61 Drinking Water System Components— have a hoop stress distribution that differs substantially from
Health Effects both the thick and thin walled pipe cases.
Standard No. 14 Plastics Piping System Components and
Related Materials 4. Pipe Classification
2.3 Federal Standard:
4.1 Pipe Diameter—The PEX-AL-PEX pipes are classified
Fed. Std. No. 123 Marking for Shipments (Civil Agencies)
by the outside diameter.
2.4 Military Standard:
4.2 Pipe Dimension Ratio—The concept of dimension ratio
MIL-STD-129 Marking for Shipment and Storage
is not relevant to PEX-AL-PEX composite pipes, and cannot
2.5 Uniform Classification Committee Standard:
be used to relate pressure rating with total wall thickness.
Uniform Freight Classification
2.6 National Motor Freight Traffıc Association Standard:
5. Materials
National Motor Freight Classification
5.1 General—The PEX-AL-PEX pipe is composed of one
3. Terminology
metallic layer, two layers of polymeric adhesive, and two
3.1 Definitions—Definitions are in accordance with Termi- layers of crosslinked polyethylene. For pipe made to this
nology F412, and abbreviations are in accordance with Termi- specification the constituent materials must meet the following
nology D1600, unless otherwise specified. requirements:
3.2 Definitions of Terms Specific to This Standard:
5.2 Aluminum—The aluminum shall have a thickness as
3.2.1 assembly—the joint between a fitting and a length of specified in Table 1. The material shall have minimum elon-
pipe.
gations and ultimate tensile strengths of 20 % and 100 MPa
(14 600 psi), respectively. The tests shall be conducted accord-
3.2.2 PEX-AL-PEX pipe—composite pipe produced by co-
ing to Test Methods E8/E8M.
extrusion or extrusion of layers of polyethylene/aluminum/
polyethylene bonded together with a melt adhesive and cross-
5.3 Crosslinked Polyethylene:
linked by irradiation or chemical means in combination heat
5.3.1 The polyethylene shall be, in the final finished state in
and moisture.
the pipe, crosslinked as defined in Terminology D883.
5.3.2 Polyethylene plastics used to make pipe meeting the
3.2.3 pipe hoop stress—for simplicity the value of the hoop
requirements of this specification shall be virgin resin meeting
stress quoted assumes a homogeneous wall. Local values of
the requirements of either Grade PE20A, B, or C; Grade
stress will vary with the different layers (see 3.2.3.1).
PE23A, B, or C; Grade PE30A, B, or C; or Grade PE33A, B,
3.2.3.1 Discussion—Thick walled plastic pipes produced
or C in accordance with Specification D3350.
from one material have hoop stresses that vary through the
5.3.3 Class B compounds shall have sufficient ultraviolet
wall, and are usually described by the Lame Theory. The
(UV) stabilizers to protect the pipe from deleterious effects due
composite nature of the PEX-AL-PEX pipe, composed of
materials with very different Young’s Modulus values, will, on to continuous outdoor exposure during storage and shipping.
Pipe produced from Class B compounds are not suitable for
pressurization, not have a uniform stress distribution through
exposed outdoor application. Class A, B, and C compounds
shall have sufficient antioxidants to meet the requirements in
Available from NSF International, P.O. Box 130140, 789 N. Dixboro Rd., Ann
Specification D3350.
Arbor, MI 48113-0140, http://www.nsf.org.
Available from DLA Document Services, Building 4/D, 700 Robbins Ave.,
5.4 Melt Adhesive—The material shall have a density cell of
Philadelphia, PA 19111-5094, http://quicksearch.dla.mil.
1, 2, or 3; a melt index cell of 1, 2, or 3; and a color code of
Available from the Uniform Classification Committee, Suite 1106, 222 South
A or B, in accordance with Specification D3350.
Riverside Plaza, Chicago, IL 60606.
Available from the National Motor Freight Traffic Association, Inc., National
5.5 Rework Material—The use of reclaimed, recycled, or
Motor Freight Classification, American Tracking Associations, Inc., Traffic Dept.,
rework plastics is not permitted.
1616 P St., NW, Washington, DC 20036.
TABLE 1 Outside Diameters, Aluminum Thickness, and Tolerances for PEX-AL-PEX
Diameter Nominal
Minimum Outside Tolerance on Minimum, Maximum Out-of- Minimum Aluminum Tolerance on Thickness,
Nominal Pipe Size
A
Diameter, mm (in.) mm (in.) Roundness, mm (in.) Thickness, mm (in.) mm (in.)
(DN) (NPS)
12 ⁄8 12.00 (0.472) +0.30 (0.012) 0.3 (0.012) 0.18 (0.007) +0.09 (+0.0035)
16 ⁄4 16.00 (0.630) +0.30 (0.012) 0.4 (0.016) 0.18 (0.007) +0.15 (+0.006)
20 ⁄8 20.00 (0.787) +0.30 (0.012) 0.5 (0.020) 0.23 (0.009) +0.23 (+0.009)
25 ⁄4 25.00 (0.984) +0.30 (0.012) 0.5 (0.020) 0.23 (0.009) +0.09 (+0.0035)
26 ⁄8 26.00 (1.022) +0.30 (0.012) 0.5 (0.020) 0.53 (0.021) +0.10 (+0.004)
32 1 32.00 (1.260) +0.30 (0.012) 0.5 (0.020) 0.28 (0.011) +0.09 (+0.0035)
40 1 ⁄4 39.95 (1.573) +0.30 (0.012) 0.5 (0.020) 0.33 (0.013) .
50 1 ⁄2 49.90 (1.964) +0.30 (0.012) 0.5 (0.020) 0.47 (0.018) .
63 2 62.90 (2.484) +0.40 (0.016) 0.5 (0.020) 0.57 (0.022) .
75 2 ⁄4 75.10 (2.957) +0.60 (0.024) 1.0 (0.039) 0.67 (0.026) .
A
The out-of-roundness specification applies only to tubing prior to coiling.
´1
F1281 − 17 (2021)
6. Requirements 6.6 Sustained Pressure—The PEX-AL-PEX pipe shall not
fail, balloon, burst, or weep, as defined in Test Method D1598,
6.1 General—The requirements and test methods in this
when tested for 10 h at the test at the test pressure given in
specification cover PEX-AL-PEX pipes. Tests on the indi-
Table 5 at a temperature of 82 °C (180 °F) in accordance with
vidual layers that comprise this composite pipe are outside the
9.6.
scope of this specification. The raw materials used, however,
must conform to the requirements as set out in Section 5.
6.7 Gel Content—When tested in accordance with 9.7, the
gel content of the inner and outer tubes of crosslinked
6.2 Dimensions and Tolerances of Pipe:
polyethylene shall have minimum values of either 65 % for the
6.2.1 Pipe Diameter—The minimum outside diameter and
fully crosslinked silane material or 60 % for radiation cross-
tolerances of the pipe shall meet the requirements given in
linked polyethylene. Test Methods D2765 defines gel content
Table 1, when measured in accordance with 9.1 and 9.1.2.
(see Note 2).
Maximum and minimum (out-of-roundness) tolerances apply
only to measurements made on pipe prior to coiling.
NOTE 1—The gel test is one of several methods capable of indicating
6.2.2 Pipe Wall Thickness—The total pipe wall thickness the degree of crosslinking. The different methods for assessing degree of
crosslinking do not necessarily agree, so conformity to this specification
shall meet the requirements given in Table 2, when measured
requires degree of crosslinking to be determined in accordance with 9.7
in accordance with 9.1 and 9.1.3. The minimum wall thickness
only.
at any point of measurement of the pipe shall not be less than
the value specified in Table 2.
7. Workmanship
6.2.3 Inner and Outer Crosslinked Polyethylene Layer
7.1 The pipe shall be free of visible cracks, holes, foreign
Thicknesses—The thicknesses of the inner and outer layers of
inclusions, blisters, and other known injurious defects. The
crosslinked polyethylene in the PEX-AL-PEX pipe shall have
pipe shall be as uniform as practicable in color, opacity,
minimum values and tolerance as specified in Table 2, except
density, and other physical properties.
for the polyethylene material in the outer PEX layer overlaying
the weld, which shall have a minimum thickness of half those
8. Sampling and Conditioning
specified in Table 2. The polyethylene thicknesses shall be
measured in accordance with 9.2.
8.1 Sampling—Take a sample of the PEX-AL-PEX pipe
6.2.4 Pipe Length—The pipe shall be supplied coiled or in
sufficient to determine conformance with this specification.
straight lengths as agreed upon with the purchaser and with an
The number of specimens designated for each test shall be
allowable tolerance of −0 mm (−0 in.).
taken from pipe selected at random in accordance with the
6.3 Adhesion Test: random sampling plan of Practice D1898.
6.3.1 For Sizes 0912 ( ⁄8) to 2532 (1) there shall be no
NOTE 2—Sample size and testing frequency of lots for quality control
delamination of the PEX and AL, either on the bore side or the
must be established by the manufacturer to ensure conformance to the
outside (see Fig. 1). The test shall be conducted in accordance
specification. Sampling and frequency will vary with the specific circum-
stances.
with 9.3.1.
6.3.2 The adhesion test of the PEX-layer to the aluminum
8.2 Test Specimens—Not less than 50 % of the test speci-
1 1
for Sizes 3240 (1 ⁄4) to 6075 (2 ⁄2) is carried out by a separation
mens required for any pressure test shall have at least part of
test. The minimum adhesive force is specified in Table 3. The
the marking in their central sections. The central section is that
adhesive force shall not fall below these levels. The test shall
portion of the pipe that is at least one pipe diameter away from
be conducted in accordance with 9.3.2.
an end closure.
6.4 Apparent Tensile Strength of Pipe—The pipe rings,
8.3 Conditioning—Condition the specimens at 23 °C 6
when tested in accordance with 9.4, shall meet the minimum
2 °C (73.4 °F 6 3.6 °F) and 50 % 6 5 % relative humidity for
strength specifications defined in Table 4.
not less than 40 h prior to test in accordance with Procedure A
6.5 Burst Pressure—The minimum burst pressure for PEX- of Practice D618, for those tests where conditioning is re-
AL-PEX pipe shall be as given in Table 4, when determined in quired. In cases of disagreement, the tolerances shall be 61 °C
accordance with 9.5. (61.8 °F) and 62 % r
...

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. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: F1281 − 17 F1281 − 17 (Reapproved 2021) An American National Standard
Standard Specification for
Crosslinked Polyethylene/Aluminum/Crosslinked
Polyethylene (PEX-AL-PEX) Pressure Pipe
This standard is issued under the fixed designation F1281; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—The units in Annex A2 were editorially revised in October 2021.
1. Scope*
1.1 This specification covers a coextruded crosslinked polyethylene composite pressure pipe with a welded aluminum tube
reinforcement between the inner and outer layers. The inner and outer crosslinked polyethylene layers are bonded to the aluminum
tube by a melt adhesive. Included is a system of nomenclature for the crosslinked polyethylene-aluminum-crosslinked polyethylene
(PEX-AL-PEX) pipes, the requirements and test methods for materials, the dimensions of the component layers and finished pipe,
adhesion tests, and the burst and sustained pressure performance. Also given are the requirements and methods of marking. The
pipe covered by this specification is intended for use in potable water distribution systems for residential and commercial
applications, water service, underground irrigation systems, and radient panel heating systems, baseboard, snow- and ice-melt
systems, and gases that are compatible with the composite pipe and fittings.
1.2 This specification covers only composite pipes incorporating a welded aluminum tube. Pipes consisting of metallic layers not
welded together are outside the scope of this specification.
1.3 Specifications for connectors for use with pipe meeting the requirements of this specification are given in Annex A1.
1.4 This specification excludes polyethylene-aluminum-polyethylene pipes (see Specification F1282).
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.after
SI units are provided for information only and are not considered standard.
1.6 The following precautionary caveat pertains only to the test methods portion, Section 9, of this specification: This standard
does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this
standard to establish appropriate safety, health and environmental practices and determine the applicability of regulatory
limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This specification is under the jurisdiction of ASTM Committee F17 on Plastic Piping Systems and is the direct responsibility of Subcommittee F17.11 on Composite.
Current edition approved Aug. 1, 2017. Published August 2017 October 2021. Originally approved in 1990. Last previous edition approved in 20112017 as
F1281 – 11.F1281 – 17. DOI: 10.1520/F1281-17.10.1520/F1281-17R21E01.
*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
´1
F1281 − 17 (2021)
2. Referenced Documents
2.1 ASTM Standards:
D618 Practice for Conditioning Plastics for Testing
D883 Terminology Relating to Plastics
D1598 Test Method for Time-to-Failure of Plastic Pipe Under Constant Internal Pressure
D1599 Test Method for Resistance to Short-Time Hydraulic Pressure of Plastic Pipe, Tubing, and Fittings
D1600 Terminology for Abbreviated Terms Relating to Plastics
D1898 Practice for Sampling of Plastics (Withdrawn 1998)
D2122 Test Method for Determining Dimensions of Thermoplastic Pipe and Fittings
D2765 Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics
D3350 Specification for Polyethylene Plastics Pipe and Fittings Materials
E8E8/E8M Test Methods for Tension Testing of Metallic Materials [Metric] E0008_E0008M
F412 Terminology Relating to Plastic Piping Systems
F1282 Specification for Polyethylene/Aluminum/Polyethylene (PE-AL-PE) Composite Pressure Pipe
F1974 Specification for Metal Insert Fittings for Polyethylene/Aluminum/Polyethylene and Crosslinked Polyethylene/
Aluminum/Crosslinked Polyethylene Composite Pressure Pipe
2.2 National Sanitation Foundation Standard:
Standard No. 61 Drinking Water System Components—Health Effects
Standard No. 14 Plastics Piping System Components and Related Materials
2.3 Federal Standard:
Fed. Std. No. 123 Marking for Shipments (Civil Agencies)
2.4 Military Standard:
MIL-STD-129 Marking for Shipment and Storage
2.5 Uniform Classification Committee Standard:
Uniform Freight Classification
2.6 National Motor Freight Traffıc Association Standard:
National Motor Freight Classification
3. Terminology
3.1 Definitions—Definitions are in accordance with Terminology F412, and abbreviations are in accordance with Terminology
D1600, unless otherwise specified.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 assembly—the joint between a fitting and a length of pipe.
3.2.2 PEX-AL-PEX pipe—composite pipe produced by coextrusion or extrusion of layers of polyethylene/aluminum/polyethylene
bonded together with a melt adhesive and crosslinked by irradiation or chemical means in combination heat and moisture.
3.2.3 pipe hoop stress—for simplicity the value of the hoop stress quoted assumes a homogeneous wall. Local values of stress will
vary with the different layers (see 3.2.3.1).
3.2.3.1 Discussion—
Thick walled plastic pipes produced from one material have hoop stresses that vary through the wall, and are usually described
by the Lame Theory. The composite nature of the PEX-AL-PEX pipe, composed of materials with very different Young’s Modulus
values, will, on pressurization, not have a uniform stress distribution through the thickness of the wall of the pipe. The
PEX-AL-PEX pipes have a hoop stress distribution that differs substantially from both the thick and thin walled pipe cases.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Available from NSF International, P.O. Box 130140, 789 N. Dixboro Rd., Ann Arbor, MI 48113-0140, http://www.nsf.org.
Available from DLA Document Services, Building 4/D, 700 Robbins Ave., Philadelphia, PA 19111-5094, http://quicksearch.dla.mil.
Available from the Uniform Classification Committee, Suite 1106, 222 South Riverside Plaza, Chicago, IL 60606.
Available from the National Motor Freight Traffic Association, Inc., National Motor Freight Classification, American Tracking Associations, Inc., Traffic Dept., 1616 P
St., NW, Washington, DC 20036.
´1
F1281 − 17 (2021)
4. Pipe Classification
4.1 Pipe Diameter—The PEX-AL-PEX pipes are classified by the outside diameter.
4.2 Pipe Dimension Ratio—The concept of dimension ratio is not relevant to PEX-AL-PEX composite pipes, and cannot be used
to relate pressure rating with total wall thickness.
5. Materials
5.1 General—The PEX-AL-PEX pipe is composed of one metallic layer, two layers of polymeric adhesive, and two layers of
crosslinked polyethylene. For pipe made to this specification the constituent materials must meet the following requirements:
5.2 Aluminum—The aluminum shall have a thickness as specified in Table 1. The material shall have minimum elongations and
ultimate tensile strengths of 20 % and 100 MPa (14 600 psi), respectively. The tests shall be conducted according to Test Methods
E8E8/E8M.
5.3 Crosslinked Polyethylene:
5.3.1 The polyethylene shall be, in the final finished state in the pipe, crosslinked as defined in Terminology D883.
5.3.2 Polyethylene plastics used to make pipe meeting the requirements of this specification shall be virgin resin meeting the
requirements of either Grade PE20A, B, or C; Grade PE23A, B, or C; Grade PE30A, B, or C; or Grade PE33A, B, or C in
accordance with Specification D3350.
5.3.3 Class B compounds shall have sufficient ultraviolet (UV) stabilizers to protect the pipe from deleterious effects due to
continuous outdoor exposure during storage and shipping. Pipe produced from Class B compounds are not suitable for exposed
outdoor application. Class A, B, and C compounds shall have sufficient antioxidants to meet the requirements in Specification
D3350.
5.4 Melt Adhesive—The material shall have a density cell of 1, 2, or 3; a melt index cell of 1, 2, or 3; and a color code of A or
B, in accordance with Specification D3350.
5.5 Rework Material—The use of reclaimed, recycled, or rework plastics is not permitted.
6. Requirements
6.1 General—The requirements and test methods in this specification cover PEX-AL-PEX pipes. Tests on the individual layers
that comprise this composite pipe are outside the scope of this specification. The raw materials used, however, must conform to
the requirements as set out in Section 5.
6.2 Dimensions and Tolerances of Pipe:
TABLE 1 Outside Diameters, Aluminum Thickness, and Tolerances for PEX-AL-PEX
Diameter Nominal
Minimum Outside Tolerance on Minimum, Maximum Out-of- Minimum Aluminum Tolerance on Thickness,
Nominal Pipe Size
A
Diameter, mm (in.) mm (in.) Roundness, mm (in.) Thickness, mm (in.) mm (in.)
(DN) (NPS)
12 ⁄8 12.00 (0.472) +0.30 (0.012) 0.3 (0.012) 0.18 (0.007) +0.09 (+0.0035)
16 ⁄4 16.00 (0.630) +0.30 (0.012) 0.4 (0.016) 0.18 (0.007) +0.15 (+0.006)
20 ⁄8 20.00 (0.787) +0.30 (0.012) 0.5 (0.020) 0.23 (0.009) +0.23 (+0.009)
25 ⁄4 25.00 (0.984) +0.30 (0.012) 0.5 (0.020) 0.23 (0.009) +0.09 (+0.0035)
26 ⁄8 26.00 (1.022) +0.30 (0.012) 0.5 (0.020) 0.53 (0.021) +0.10 (+0.004)
32 1 32.00 (1.260) +0.30 (0.012) 0.5 (0.020) 0.28 (0.011) +0.09 (+0.0035)
40 1 ⁄4 39.95 (1.573) +0.30 (0.012) 0.5 (0.020) 0.33 (0.013) .
50 1 ⁄2 49.90 (1.964) +0.30 (0.012) 0.5 (0.020) 0.47 (0.018) .
63 2 62.90 (2.484) +0.40 (0.016) 0.5 (0.020) 0.57 (0.022) .
75 2 ⁄4 75.10 (2.957) +0.60 (0.024) 1.0 (0.039) 0.67 (0.026) .
A
The out-of-roundness specification applies only to tubing prior to coiling.
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6.2.1 Pipe Diameter—The minimum outside diameter and tolerances of the pipe shall meet the requirements given in Table 1,
when measured in accordance with 9.1 and 9.1.2. Maximum and minimum (out-of-roundness) tolerances apply only to
measurements made on pipe prior to coiling.
6.2.2 Pipe Wall Thickness—The total pipe wall thickness shall meet the requirements given in Table 2, when measured in
accordance with 9.1 and 9.1.3. The minimum wall thickness at any point of measurement of the pipe shall not be less than the value
specified in Table 2.
6.2.3 Inner and Outer Crosslinked Polyethylene Layer Thicknesses—The thicknesses of the inner and outer layers of crosslinked
polyethylene in the PEX-AL-PEX pipe shall have minimum values and tolerance as specified in Table 2, except for the
polyethylene material in the outer PEX layer overlaying the weld, which shall have a minimum thickness of half those specified
in Table 2. The polyethylene thicknesses shall be measured in accordance with 9.2.
6.2.4 Pipe Length—The pipe shall be supplied coiled or in straight lengths as agreed upon with the purchaser and with an
allowable tolerance of −0 mm (−0 in.).
6.3 Adhesion Test:
6.3.1 For Sizes 0912 ( ⁄8) to 2532 (1) there shall be no delamination of the PEX and AL, either on the bore side or the outside
(see Fig. 1). The test shall be conducted in accordance with 9.3.1.
1 1
6.3.2 The adhesion test of the PEX-layer to the aluminum for Sizes 3240 (1 ⁄4) to 6075 (2 ⁄2) is carried out by a separation test.
The minimum adhesive force is specified in Table 3. The adhesive force shall not fall below these levels. The test shall be
conducted in accordance with 9.3.2.
6.4 Apparent Tensile Strength of Pipe—The pipe rings, when tested in accordance with 9.4, shall meet the minimum strength
specifications defined in Table 4.
6.5 Burst Pressure—The minimum burst pressure for PEX-AL-PEX pipe shall be as given in Table 4, when determined in
accordance with 9.5.
6.6 Sustained Pressure—The PEX-AL-PEX pipe shall not fail, balloon, burst, or weep, as defined in Test Method D1598, when
tested for 10 h at the test at the test pressure given in Table 5 at a temperature of 82°C (180°F)82 °C (180 °F) in accordance with
9.6.
6.7 Gel Content—When tested in accordance with 9.7, the gel content of the inner and outer tubes of crosslinked polyethylene
shall have minimum values of either 65 % for the fully crosslinked silane material or 60 % for radiation crosslinked polyethylene.
Test Methods D2765 defines gel content (see Note 2).
NOTE 1—The gel test is one of several methods capable of indicating the degree of crosslinking. The different methods for assessing degree of crosslinking
do not necessarily agree, so conformity to this specification requires degree of crosslinking to be determined in accordance with 9.7 only.
TABLE 2 Wall Thickness for PEX-AL-PEX Composite Pipe
Total Wall Wall Outer PEX Inner PEX
Diameter Nominal Nominal Pipe Size
Thickness, min, Tolerance Layer Thickness, Layer Thickness,
(DN) (NPS)
mm (in.) (+) mm (in.) min, mm (in.) min, mm (in.)
12 ⁄8 1.60 (0.063) 0.40 (0.016) 0.40 (0.016) 0.70 (0.028)
16 ⁄4 1.65 (0.065) 0.65 (0.022) 0.40 (0.016) 0.90 (0.035)
20 ⁄8 1.90 (0.075) 0.40 (0.016) 0.40 (0.016) 0.96 (0.038)
25 ⁄4 2.25 (0.089) 0.50 (0.020) 0.40 (0.016) 1.10 (0.043)
26 ⁄8 3.00 (0.118) 0.33 (0.013) 0.40 (0.016) 1.32 (0.052)
32 1 2.90 (0.114) 0.60 (0.024) 0.40 (0.016) 1.34 (0.053)
40 1 ⁄4 3.40 (0.134) 0.60 (0.024) 0.40 (0.016) 1.45 (0.057)
50 1 ⁄2 4.00 (0.157) 0.60 (0.024) 0.40 (0.016) 1.75 (0.069)
63 2 4.60 (0.181) 0.60 (0.024) 0.40 (0.016) 1.75 (0.069)
75 2 ⁄4 7.25 (0.285) 0.60 (0.024) 0.40 (0.016) 2.80 (0.110)
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NOTE 1—(a) Good pipe showing no
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