ISO 4437-2:2026

• Abstract:

  This document specifies the characteristics of pipes made from polyethylene (PE) for piping systems in the field of the supply of gaseous fuels. NOTE 1 Additional information related to the installation of PE 100-RC systems is given in ISO 4437-1:2026, Annex A. NOTE 2 Additional information about the suitability of PE pipe systems for hydrogen and its admixtures is given in ISO 4437-1:2026, Annex D. It also specifies the test parameters for the test methods referred to in this document. In conjunction with ISO 4437-1, ISO 4437-3, ISO 4437-4 and ISO 4437-5, this document is applicable to PE pipes, fittings and valves, their joints, and joints with components of PE and other materials intended to be used under the following conditions: a maximum operating pressure (MOP) up to and including 10 bar1), at a design reference temperature of 20 °C; an operating temperature between −20 °C and 40 °C. For operating temperatures between 20 °C and 40 °C, derating coefficients are specified in ISO 4437-5. The ISO 4437 series covers a range of MOPs and gives requirements concerning colours. This document is applicable to three types of pipe: PE pipes (outside diameter, dn) including any identification stripes; PE pipes with co-extruded layers on either or both the outside and/or inside of the pipe (total outside diameter, dn) as specified in Annex A, where all PE layers have the same MRS rating; PE pipes (outside diameter, dn) with a peelable and contiguous thermoplastics additional layer on the outside of the pipe ("coated pipe") as specified in Annex B. It is the responsibility of the purchaser or specifier to make the appropriate selections from these aspects, taking into account their particular requirements and any relevant national guidance or regulations and installation practices or codes. 1)1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm2.

• Status: Published
• Publication Date: 13-Oct-2026
• ICS: 75.200 - Petroleum products and natural gas handling equipment
• ICS: 83.140.30 - Plastics pipes and fittings for non fluid use
• Technical Committee: ISO/TC 138/SC 4 - Plastics pipes and fittings for the supply of gaseous fuels
• Drafting Committee: ISO/TC 138/SC 4/WG 3 - PE Pipe Systems
• Current Stage: 6060 - International Standard published
• Start Date: 14-Oct-2026
• Completion Date: 14-Oct-2026

• Revises: ISO 4437-2:2024 - Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 2: Pipes
• Effective Date: 21-Sep-2024

ISO 4437-2:2026 is an ISO International Standard for polyethylene (PE) pipes used in the supply of gaseous fuels. It specifies pipe characteristics, test parameters, and marking for plain PE pipes, co-extruded pipes, and pipes with a peelable outer layer, for users who select, manufacture, test, buy, or specify these pipes.

What does ISO 4437-2:2026 specify?

ISO 4437-2:2026 specifies the characteristics of PE pipes for gas-supply piping systems and the test parameters for the test methods referenced in the document. It is used together with ISO 4437-1, ISO 4437-3, ISO 4437-4 and ISO 4437-5 for systems intended for a maximum operating pressure (MOP) up to and including 10 bar, at a design reference temperature of 20 °C, and for operating temperatures from -20 °C to 40 °C.

The document covers three pipe types:

• PE pipes with identification stripes
• PE pipes with co-extruded layers on the outside and/or inside
• PE pipes with a peelable and contiguous thermoplastics outer layer, also called coated pipe

The document is organized into Clauses 1 to 11, followed by three normative annexes.

Annex	What it covers
Annex A	Pipes with co-extruded layers
Annex B	Pipes with peelable layer
Annex C	Squeeze-off technique

What are the key requirements of ISO 4437-2:2026?

ISO 4437-2:2026 sets requirements for material choice, geometry, mechanical and physical performance, and marking. In practice, these clauses tell a manufacturer what pipe to make, what to test, and what information must stay visible on the pipe.

Material and pipe construction

Clause 5 requires the PE compound for pipes to conform to ISO 4437-1. The pipe may be made from virgin material, reworked material from the same PE compound within the manufacturer’s own plants, or a mixture of those materials. Reworked material from co-extruded pipes, and external reworked material or recyclate, shall not be used. For a pipe to be designated PE 100-RC, the material and the finished pipe have to meet the stated PE 100-RC conditions and the raw material has to be declared as PE 100-RC by the material manufacturer.

Clause 5 also controls identification stripes. The stripe compound has to be based on a PE base polymer with proven fusion compatibility, and its oxidation induction time (OIT) has to meet the stated requirement. This matters because stripes are part of traceability and identification, but they still have to perform like the pipe material.

Appearance, colour and dimensions

Clause 6 requires smooth, clean internal and external surfaces and clean, square pipe ends. It also defines permitted pipe colours and stripe colours for PE 80, PE 100 and PE 100-RC. This helps users check deliveries quickly and reduces confusion on site.

Clause 7 covers dimensions. Pipe dimensions are measured in accordance with ISO 3126, and the clause sets the mean outside diameters, out-of-roundness limits, wall thicknesses, tolerances, coil diameter, and supplied lengths. For coiled pipe, the internal coil diameter has to prevent local deformation such as buckling and kinking. In practice, this is the section a buyer uses to confirm that the pipe will fit fittings, handling equipment, trenching practice, and storage constraints.

Mechanical performance

Clause 8 requires conditioning of test pieces and then mechanical testing against the stated parameters. The key checks include hydrostatic strength at 20 °C and 80 °C, long-duration hydrostatic strength, tensile elongation at break, slow crack growth resistance, and rapid crack propagation resistance where applicable. The clause also links to Annex C if squeeze-off is requested by the end user.

These requirements matter because they screen for the main field risks in gas pipe service: pressure resistance, long-term cracking, and damage from handling or repair operations. For PE 100-RC pipes, the document adds specific tests such as strain hardening and cracked round bar testing.

Physical characteristics and system performance

Clause 9 covers oxidation induction time, melt mass-flow rate, longitudinal reversion, and dispersion checks for carbon black or pigment. It also sets a circumferential reversion check for pipes with larger diameters. In practice, these tests help confirm that the material has the expected thermal stability, processing consistency, and dimensional behavior after heating.

Clause 10 states that when pipes are assembled to each other or to other components of the ISO 4437 series, the joints shall conform to ISO 4437-5. This means the pipe standard does not stand alone at system level - the joint performance has to be checked against the system part.

Marking

Clause 11 requires durable marking that remains legible through storage, weathering, handling and installation. The minimum marking includes the ISO 4437 reference, the manufacturer’s identification, size information, SDR, pipe type where relevant, designation, intended use, and traceability information. For users, this is what supports stock control, site identification, and later investigation if a problem occurs.

What terms does ISO 4437-2:2026 define?

ISO 4437-2:2026 uses the terms in ISO 4437-1 and adds a set of pipe-related definitions. The most useful ones for day-to-day use are:

• Nominal size (DN/OD) - a size designation related to outside diameter, used to identify matching pipes and components.
• Nominal outside diameter - the specified outside diameter assigned to a nominal size.
• Mean outside diameter - the measured outside circumference divided by pi and rounded as specified, used to check dimensional conformity.
• Out-of-roundness (ovality) - the difference between the largest and smallest outside diameter in the same cross-section.
• Standard dimension ratio (SDR) - the numerical pipe series based on the relation between nominal outside diameter and nominal wall thickness.
• Pipe series (S) - the number used for pipe designation and related to SDR by the ISO 4065 relationship.
• Compound - the homogeneous extruded mixture of polyethylene base polymer and additives used to make the pipe.
• Squeeze-off - restriction of gas flow by mechanical compression of the pipe.
• Maximum operating pressure (MOP) - the pressure limit used to define the intended service condition.
• Melt mass-flow rate (MFR) - a measure used to check the flow behavior of the polymer melt.

Who uses ISO 4437-2:2026?

ISO 4437-2:2026 is used by pipe manufacturers, gas network operators, specifiers, purchasers, quality managers, and test laboratories. Manufacturers use it to set material selection, extrusion control, and marking. Buyers and specifiers use it to choose the right pipe type, size, SDR, and special construction for a project. Laboratories and inspectors use it to run the specified mechanical, physical, and dimensional tests. It is most relevant in the gas distribution and plastics piping sectors.

What changed in ISO 4437-2:2026 from the previous edition?

ISO 4437-2:2026 is the third edition and it replaces ISO 4437-2:2024. The foreword states that it was technically revised, with these main changes:

• added reference to information on suitability for 100 % hydrogen and its admixtures with natural gas
• redistributed terms and definitions across ISO 4437-1, ISO 4437-2 and ISO 4437-3
• restructured Clause 5.1 on the compound for pipes
• aligned minimum wall thickness for DN 400, DN 500, DN 560 and DN 630 SDR 11 with ISO 4065
• moved circumferential reversion to Clause 9.3
• added a conversion and normalisation step for the CRB test
• made the performance requirements for joints more explicit by adding Table 7

Which standards are used with ISO 4437-2:2026?

ISO 4437-2:2026 is used with several other ISO 4437 parts and supporting test standards. The most relevant are:

• ISO 4437-1 - gives general requirements for the PE gas piping system and the base material requirements
• ISO 4437-3 - covers fittings
• ISO 4437-4 - covers valves
• ISO 4437-5 - covers fitness for purpose of the system and joint performance
• ISO 4437-7 - gives guidance on assessment of conformity
• ISO/TS 10839 - gives recommended practice for design, handling and installation
• ISO 4065 - provides the universal wall thickness relationship used for SDR-related wall thicknesses

The document also relies on a range of test standards, including ISO 1167, ISO 2505, ISO 3126, ISO 6259, ISO 9969, ISO 1133-1, ISO 11357-6, ISO 13477, ISO 13478, ISO 13479, ISO 13968, ISO 18488 and ISO 18489.

What does the ISO 4437-2:2026 document contain?

ISO 4437-2:2026 contains the pipe-specific part of the ISO 4437 series. It brings together scope, normative references, terms and symbols, material rules, appearance and colour, dimensional requirements, mechanical and physical test requirements, system-level performance references, and marking.

It also contains the main reference tables for diameter, ovality, wall thickness, tolerances, test parameters, retest conditions, physical-property limits, joint performance, and minimum marking. Annex A adds layered-pipe requirements, including delamination and structural integrity after deflection. Annex B adds requirements for coated pipe, including peelable-layer adhesion and removal before jointing. Annex C gives the squeeze-off condition under which the pipe has to recover and still meet the long-term hydrostatic requirement.

International
Standard
ISO 4437-2
Third edition
Plastics piping systems for
2026-10
the supply of gaseous fuels —
Polyethylene (PE) —
Part 2:
Pipes
Systèmes de canalisations en plastique pour la distribution de
combustibles gazeux — Polyéthylène (PE) —
Partie 2: Tubes
Reference number
© ISO 2026
All rights reserved.
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Any use beyond the scope of the granted rights is prohibited and may result in legal action.
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
3.1 Terms related to geometry .3
3.2 Terms related to material .4
3.3 Terms related to joints .5
4 Symbols and abbreviated terms. 5
4.1 Symbols .5
4.2 Abbreviated terms .6
5 Material. 6
5.1 Compound for pipes .6
5.2 Compound for identification stripes .7
5.3 External reworked material and recyclate .7
6 General characteristics . 7
6.1 Appearance .7
6.2 Colour .7
7 Geometrical characteristics . 7
7.1 Measurement of dimensions .7
7.2 Mean outside diameters, out-of-roundness (ovality) and tolerances .8
7.3 Wall thicknesses and related tolerances .9
7.3.1 Minimum wall thicknesses.9
7.3.2 Tolerance on the wall thicknesses .10
7.4 Coiled pipe .11
7.5 Lengths .11
8 Mechanical characteristics .11
8.1 Conditioning.11
8.2 Requirements .11
9 Physical characteristics .15
9.1 Conditioning. 15
9.2 Requirements . 15
9.3 Circumferential reversion of pipes with d ≥ 250 mm.16
n
10 Performance requirements . .16
11 Marking . .16
11.1 General .16
11.2 Minimum required marking .16
Annex A (normative) Pipes with co-extruded layers .18
Annex B (normative) Pipes with peelable layer .20
Annex C (normative) Squeeze-off technique .22
Bibliography .23

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 4, Plastics pipes and fittings for the supply of gaseous fuels.
This third edition cancels and replaces the second edition (ISO 4437-2:2024), which has been technically
revised.
The main changes are as follows:
— reference to information related to the suitability of PE pipe systems for 100 % hydrogen and its
admixtures with natural gas has been made;
— terms and definitions have been distributed over ISO 4437-1, ISO 4437-2 and ISO 4437-3;
— subclause 5.1, about the compound for pipes, has been restructured;
— the minimum wall thickness for DN 400, DN 500, DN 560 and DN 630 SDR 11 have been aligned with
ISO 4065;
— the circumferential reversion has been moved to subclause 9.3;
— a conversion and normalisation step has been included to the requirement for the CRB;
— the performance requirements for joints have been mentioned more explicitly by adding Table 7.
A list of all parts in the ISO 4437 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
The ISO 4437 series specifies the requirements for a piping system and its components made from
polyethylene (PE) compounds, which is intended to be used for the supply of gaseous fuels.
This document covers the characteristics of pipes.
Requirements and test methods for materials and components, other than pipes, are specified in ISO 4437-1,
ISO 4437-3 and ISO 4437-4.
Characteristics for fitness for purpose of the system are covered in ISO 4437-5. ISO/TS 4437-7 gives guidance
for assessment of conformity.
Recommended practice for design, handling and installation is given in ISO/TS 10839.

v
International Standard ISO 4437-2:2026(en)
Plastics piping systems for the supply of gaseous fuels —
Polyethylene (PE) —
Part 2:
Pipes
1 Scope
This document specifies the characteristics of pipes made from polyethylene (PE) for piping systems in the
field of the supply of gaseous fuels.
NOTE 1 Additional information related to the installation of PE 100-RC systems is given in ISO 4437-1:2026,
Annex A.
NOTE 2 Additional information about the suitability of PE pipe systems for hydrogen and its admixtures is given in
ISO 4437-1:2026, Annex D.
It also specifies the test parameters for the test methods referred to in this document.
In conjunction with ISO 4437-1, ISO 4437-3, ISO 4437-4 and ISO 4437-5, this document is applicable to PE
pipes, fittings and valves, their joints, and joints with components of PE and other materials intended to be
used under the following conditions:
1)
a) a maximum operating pressure (MOP) up to and including 10 bar , at a design reference temperature of
20 °C;
b) an operating temperature between −20 °C and 40 °C.
For operating temperatures between 20 °C and 40 °C, derating coefficients are specified in ISO 4437-5.
The ISO 4437 series covers a range of MOPs and gives requirements concerning colours.
This document is applicable to three types of pipe:
— PE pipes (outside diameter, d ) including any identification stripes;
n
— PE pipes with co-extruded layers on either or both the outside and/or inside of the pipe (total outside
diameter, d ) as specified in Annex A, where all PE layers have the same MRS rating;
n
— PE pipes (outside diameter, d ) with a peelable and contiguous thermoplastics additional layer on the
n
outside of the pipe ("coated pipe") as specified in Annex B.
It is the responsibility of the purchaser or specifier to make the appropriate selections from these aspects,
taking into account their particular requirements and any relevant national guidance or regulations and
installation practices or codes.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
5 2
1) 1 bar = 0,1 MPa = 10 Pa; 1 MPa = 1 N/mm .

ISO 1133-1, Plastics — Determination of the melt mass-flow rate (MFR) and melt volume-flow rate (MVR) of
thermoplastics — Part 1: Standard method
ISO 1167-1:2006, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of
the resistance to internal pressure — Part 1: General method
ISO 1167-2, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of the
resistance to internal pressure — Part 2: Preparation of pipe test pieces
ISO 2505, Thermoplastics pipes — Longitudinal reversion — Test method and parameters
ISO 3126, Plastics piping systems — Plastics components — Determination of dimensions
ISO 4437-1, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 1: General
ISO 4437-5, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 5: Fitness for
purpose of the system
ISO 6259-1, Thermoplastics pipes — Determination of tensile properties — Part 1: General test method
ISO 6259-3, Thermoplastics pipes — Determination of tensile properties — Part 3: Polyolefin pipes
ISO 9969, Thermoplastics pipes — Determination of ring stiffness
ISO 11922-1:2018, Thermoplastics pipes for the conveyance of fluids — Dimensions and tolerances — Part 1:
Metric series
ISO 11357-6, Plastics — Differential scanning calorimetry (DSC) — Part 6: Determination of oxidation induction
time (isothermal OIT) and oxidation induction temperature (dynamic OIT)
ISO 13477, Thermoplastics pipes for the conveyance of fluids — Determination of resistance to rapid crack
propagation (RCP) — Small-scale steady-state test (S4 test)
ISO 13478, Thermoplastics pipes for the conveyance of fluids — Determination of resistance to rapid crack
propagation (RCP) — Full-scale test (FST)
ISO 13479, Polyolefin pipes for the conveyance of fluids — Determination of resistance to crack propagation —
Test method for slow crack growth on notched pipes
ISO 13968, Plastics piping and ducting systems — Thermoplastics pipes — Determination of ring flexibility
ISO 18488, Polyethylene (PE) materials for piping systems — Determination of strain hardening modulus in
relation to slow crack growth — Test method
ISO 18489:2015, Polyethylene (PE) materials for piping systems — Determination of resistance to slow crack
growth under cyclic loading — Cracked Round Bar test method
ISO 18553, Method for the assessment of the degree of pigment or carbon black dispersion in polyolefin pipes,
fittings and compounds
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4437-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/

3.1 Terms related to geometry
3.1.1
nominal size
DN/OD
numerical designation of the size of a component related to the outside diameter
Note 1 to entry: It is a convenient round number approximately equal to the manufacturing dimension in millimetres
(mm). It is not applicable to components designated by thread size.
3.1.2
nominal outside diameter
d
n
specified outside diameter assigned to a nominal size (3.1.1)
Note 1 to entry: It is expressed in millimetres (mm).
3.1.3
mean outside diameter
d
em
value of the measurement of the outer circumference of the pipe or spigot end of a fitting in any cross-section
divided by π (= 3,142), rounded to the next greater 0,1 mm
3.1.4
minimum mean outside diameter
d
em,min
minimum value for the mean outside diameter (3.1.3) as specified for a given nominal size (3.1.1)
3.1.5
maximum mean outside diameter
d
em,max
maximum value for the mean outside diameter (3.1.3) as specified for a given nominal size (3.1.1)
3.1.6
out-of-roundness
ovality
difference between the measured maximum and the measured minimum outside diameter in the same
cross-section of a component
3.1.7
nominal wall thickness
e
n
numerical designation of the wall thickness of a component, which is a convenient round number,
approximately equal to the manufacturing dimension in millimetres (mm)
Note 1 to entry: For thermoplastics components conforming to the ISO 4437 series, the value of the nominal wall
thickness, e , is identical to the specified minimum wall thickness at any point (3.1.9), e .
n min
3.1.8
wall thickness at any point
e
wall thickness at any point around the circumference of a component rounded to the next greater 0,1 mm
Note 1 to entry: The symbol for the wall thickness of a fitting and valve body at any point is E.
3.1.9
minimum wall thickness at any point
e
min
minimum value for the wall thickness at any point (3.1.8) around the circumference of a component

3.1.10
tolerance
permitted variation of the specified value of a quantity, expressed as the difference between the permitted
maximum and the permitted minimum values
3.1.11
wall thickness tolerance
T
y
permitted difference between the wall thickness at any point (3.1.8) and the nominal wall thickness (3.1.7)
Note 1 to entry: e ≤ e ≤ e + T .
n n y
3.1.12
standard dimension ratio
SDR
numerical designation of a pipe series (3.1.13), which is a convenient round number, approximately equal to
the dimension ratio of the nominal outside diameter (3.1.2) and the nominal wall thickness (3.1.7)
3.1.13
pipe series
S
number for pipe designation
Note 1 to entry: The relationship between the pipe series, S, and the standard dimension ratio, SDR, (3.1.12) is given by
the following formula, as specified in ISO 4065.
SDR−1
S=
3.2 Terms related to material
3.2.1
compound
clearly defined homogenous extruded mixture of base polymer (3.2.5) (polyethylene) and additives (i.e. anti-
oxidants, pigments, carbon black, UV-stabilizers and others) at a dosage level necessary for the processing
and use of components
3.2.2
virgin material
plastics material in the form of pellets or granules that has not been subjected to use or processing other
than that required for its initial manufacture
Note 1 to entry: Does not contain any reworked plastics material and/or plastics recyclate.
Note 2 to entry: Ethylene used for the polymerisation of the virgin material come from fossil sources (naphtha, oil, gas,
etc.), renewable sources or from chemical recycling process.
[11]
[SOURCE: EN 14541-1:2022 , 3.1, modified – powder, floc, etc. removed, Note 2 to entry removed, Note 3 to
entry removed and new Note 2 to entry added]
3.2.3
reworked material
plastics material from rejected unused products or trimmings capable of being reclaimed within the same
process that generated it
Note 1 to entry: Restrictions for use of reworked material for pipes are specified in ISO 4437-2, fittings in ISO 4437-3
and for valves in ISO 4437-4.
Note 2 to entry: Previously referred to as “own reprocessed material”.
[11]
[SOURCE: EN 14541-1:2022 , 3.2 –Note 1 to entry removed, Note 2 to entry changed]

3.2.4
recyclate
plastics material resulting from the recycling of pre-consumer and post-consumer plastics products
Note 1 to entry: Also referred to as “secondary raw material” or “recycled plastics” or “regenerate”.
Note 2 to entry: Recycling in the ISO 4437 series is physical or mechanical
[11]
[SOURCE: EN 14541-1:2022 , 3.5 — Note 2 to entry changed]
3.2.5
base polymer
polymer produced by the material supplier for the manufacture of the compound (3.2.1)
3.3 Terms related to joints
3.3.1
squeeze-off
restriction of the gas flow to an acceptable rate through mechanical compression of the pipe
Note 1 to entry: See Annex C.
4 Symbols and abbreviated terms
4.1 Symbols
For the purpose of this document, the following symbols apply.
C design coefficient
d mean outside diameter
em
d maximum mean outside diameter
em,max
d minimum mean outside diameter
em,min
d nominal outside diameter
n
e wall thickness (at any point) around the circumference of a component
e minimum wall thickness (at any point)
min
e nominal wall thickness
n
strain hardening modulus
p
p critical pressure
c
p critical pressure obtained in full-scale test
c,full-scale
p critical pressure obtained in S4-test
cS4
S pipe series
T wall thickness tolerance
y
t time
θ temperature
σ lower confidence limit of the predicted hydrostatic strength
LPL
4.2 Abbreviated terms
For the purposes of this document, the following abbreviated terms apply.
ANPT accelerated notched pipe test
CRB cracked round bar (test)
DN/OD nominal size, outside diameter-related
LPL lower predicted limit
MFR melt mass-flow rate
MOP maximum operating pressure
MRS minimum required strength
NPT notched pipe test
PE polyethylene
RC raised crack resistance
RCP rapid crack propagation
SCG slow crack growth
SDR standard dimension ratio
SHT strain hardening test
5 Material
5.1 Compound for pipes
The PE compound from which the pipes are made shall conform to ISO 4437-1.
The pipes shall be made from:
— virgin material, or
— reworked material from the extrusion process from the same PE compound from any of the manufacturer’s
own plants, or
— reworked material from the injection moulding process from the same PE compound from any of the
manufacturer’s own plants, or
— a mixture of two or more of the above, all from the same PE compound.
Reworked material may be used from:
— the base pipe of peelable layer pipe (coated pipe), and
— pipes with or without identification stripes.
For co-extruded pipes, see Annex A.
Reworked material from co-extruded pipes or from pipes reworked with the peelable layer attached shall
not be used.
A pipe can only be designated as a PE 100-RC pipe if it is produced from PE 100-RC materials, which fulfil
the requirements of ISO 4437-1:2026, Table 1 and 2, and is declared as PE 100-RC by the raw material
manufacturer, and fulfils the requirements of Table 3 and 5 of this document for PE 100-RC. A co-extruded
pipe made of a combination of PE 100 and PE 100-RC layers shall be regarded as PE 100 and marked
accordingly.
5.2 Compound for identification stripes
The stripe compound (see 6.2) shall be manufactured from a PE base polymer in accordance with ISO 4437-1,
which is used for a pipe compound for which fusion compatibility has been proven.
The compound used for identification stripes in the form of a pipe shall conform to the decohesion test
requirement of resistance to weathering as described in ISO 4437-1:2026, Table 2.
The OIT of the stripe compound shall be ≥ 20 min at 210 °C, measured by the compound supplier in
b
accordance with ISO 11357-6 (table footnote of Table 6 applies).
5.3 External reworked material and recyclate
Reworked material obtained from external sources and recyclate (pre-consumer and post-consumer
material) shall not be used.
6 General characteristics
6.1 Appearance
When viewed without magnification, the internal and external surfaces of pipes shall be smooth and clean
and shall have no scoring, cavities and other surface defects to an extent that would prevent conformity to
this document.
The ends of the pipe shall be cut cleanly and square to the axis of the pipe.
6.2 Colour
Pipes shall be black (PE 80, PE 100 and PE 100-RC), yellow (PE 80) or orange (PE 100 and PE 100-RC). In
addition, black PE 80 pipes may be identified by yellow stripes and black PE 100 and PE 100-RC pipes may be
identified by yellow or orange stripes, according to national preference.
The outer co-extruded layer of co-extruded pipes (see Annex A) or the outer peelable layer of peelable-layer
pipes (see Annex B) shall be either black, yellow or orange. In addition, identification stripes may be used
according to national preference.
National preference for colour can be stated in the National Foreword.
7 Geometrical characteristics
7.1 Measurement of dimensions
The dimensions of the pipe shall be measured in accordance with ISO 3126 and rounded to the next greater
0,1 mm. In case of dispute, the measurements of dimensions shall be made directly after conditioning for at
least 4 h at (23 ± 2) °C and at least 24 h after manufacture.
Indirect measurement at the stage of production is allowed at shorter time periods, provided that evidence
is shown of correlation.
7.2 Mean outside diameters, out-of-roundness (ovality) and tolerances
The mean outside diameters of the pipe, d , shall conform to Table 1.
em
For straight pipes, the maximum out-of-roundness shall conform to Table 1. For coiled pipes, the maximum
out-of-roundness shall be specified by agreement between the manufacturer and the end user.
Care should be taken that packaging and storage does not lead to an increased out-of-roundness and
flattening of the pipe. Additional information is given in ISO/TS 10839.
Table 1 — Mean outside diameters and out-of-roundness
Dimensions in millimetres
Nominal outside Mean outside diameter Maximum out-
Nominal size
diameter of-roundness for
a
d d
DN/OD
em,min em,max
b
d straight pipes
n
16 16 16,0 16,3 1,2
20 20 20,0 20,3 1,2
25 25 25,0 25,3 1,2
32 32 32,0 32,3 1,3
40 40 40,0 40,4 1,4
50 50 50,0 50,4 1,4
63 63 63,0 63,4 1,5
75 75 75,0 75,5 1,6
90 90 90,0 90,6 1,8
110 110 110,0 110,7 2,2
125 125 125,0 125,8 2,5
140 140 140,0 140,9 2,8
160 160 160,0 161,0 3,2
180 180 180,0 181,1 3,6
200 200 200,0 201,2 4,0
225 225 225,0 226,4 4,5
250 250 250,0 251,5 5,0
280 280 280,0 281,7 9,8
315 315 315,0 316,9 11,1
355 355 355,0 357,2 12,5
400 400 400,0 402,4 14,0
450 450 450,0 452,7 15,6
500 500 500,0 503,0 17,5
560 560 560,0 563,4 19,6
630 630 630,0 633,8 22,1
710 710 710,0 716,4 24,9
800 800 800,0 807,2 28,0
a
In accordance with ISO 11922-1:2018, except for d 50. Grade B for sizes ≤ 630, except for d 40. Grade A for sizes ≥ 710 and for
n n
d 40.
n
b
Measurement of out-of-roundness shall be made at the point of manufacturing.

7.3 Wall thicknesses and related tolerances
7.3.1
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