ISO 4437-4:2022

Plastics piping systems for the supply of gaseous fuels - Polyethylene (PE) - Part 4: Valves

This document specifies the characteristics of valves made from polyethylene (PE) for piping systems in the field of the supply of gaseous fuels. It is applicable to unidirectional and bi-directional isolating valves with spigot ends or electrofusion sockets intended to be fused with PE pipes or fittings conforming to ISO 4437−2 and ISO 4437‑3 respectively. Valves made from materials other than PE, designed for the supply of gaseous fuels conforming to the relevant standards can be used in PE piping systems according to ISO 4437 series, provided that they have PE connections for butt fusion or electrofusion ends, including integrated material transition joints, conforming to ISO 4437-3. It also specifies the test parameters for the test methods referred to in this document. In conjunction with parts 1, 2, 3 and 5 of the ISO 4437 series, this document is applicable to PE valves, their joints and to joints with components of PE and other materials intended to be used under the following conditions: a) a maximum operating pressure (MOP) up to and including 10 bar[1] at a reference temperature of 20 °C for design purposes; NOTE 1 For the purpose of this document and the references to ISO 8233, MOP is considered to be nominal pressure. b) an operating temperature between −20 °C to 40 °C. NOTE 2 For operating temperatures between 20 °C and 40 °C, derating coefficients are defined in ISO 4437‑5. This document covers valve bodies designed for connection with pipes with a nominal outside diameter dn ≤ 400 mm. [1] 1 bar = 0,1 MPa =105 Pa; 1 MPa = 1 N/mm2.

Systèmes de canalisations en plastique pour la distribution des combustibles gazeux — Polyéthylène (PE) — Partie 4: Robinets

General Information

• Status: Published
• Publication Date: 09-Nov-2022
• 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 7 - Valves and auxiliary equipment of plastics materials
• Drafting Committee: ISO/TC 138/SC 7 - Valves and auxiliary equipment of plastics materials
• Current Stage: 9092 - International Standard to be revised
• Start Date: 18-Dec-2024
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 4437-4:2015 - Plastics piping systems for the supply of gaseous fuels - Polyethylene (PE) - Part 4: Valves
• Effective Date: 26-Nov-2021

Overview

ISO 4437-4:2022 - Plastics piping systems for the supply of gaseous fuels - Polyethylene (PE) - Part 4: Valves - specifies the characteristics and test parameters for polyethylene (PE) valves used in gas supply piping systems. The standard applies to unidirectional and bi‑directional isolating valves with spigot ends or electrofusion sockets intended to be fused to PE pipes and fittings. It covers valves designed for connections with pipes up to nominal outside diameter dn ≤ 400 mm, a maximum operating pressure (MOP) up to 10 bar (at 20 °C), and normal operating temperatures from −20 °C to 40 °C.

Key topics and technical requirements

• Scope and applicability: PE valves and joints, plus joints between PE and other materials where PE fusion connections conform to ISO 4437‑3.
• Materials: Requirements for PE materials (including PE 100‑RC variants), non‑PE parts, seals, greases and transition joints.
• Design and geometry: Valve body design, spigot and electrofusion end dimensions, operating device dimensions and colour/appearance requirements.
• Mechanical and performance tests: Mechanical characteristics of assembled valves, air flow rate requirements, leaktightness, resistance to bending, tensile loading and impact/thermal cycling tests.
• Physical tests and conditioning: Conditioning procedures and physical property tests (e.g., methods referenced from ISO 1133, ISO 1167).
• Marking and technical documentation: Minimum required marking, delivery conditions and contents of the technical file.
• Test method updates: The 2022 edition adds improved leaktightness testing and updated test methods for PE 100‑RC materials; Annexes cover leaktightness and tensile‑after tests.

Practical applications and users

ISO 4437-4:2022 is intended for:

• Manufacturers of PE valves, fittings and transition joints seeking conformity with international requirements.
• Pipeline and gas distribution system designers and engineers specifying materials and components for low‑pressure and medium‑pressure gas networks.
• Installers and contractors performing butt fusion or electrofusion assembly of valves into PE piping systems.
• Regulators, certification bodies and conformity assessors evaluating valve performance, marking and test evidence.
• Specifiers and procurement teams who need to ensure component compatibility and fitness for purpose up to 10 bar MOP and within the defined temperature range.

Related Standards

• ISO 4437-1, -2, -3, -5 (PE system parts: general, pipes, fittings, fitness for purpose)
• ISO 8233 (valve torque test method)
• ISO 1133, ISO 1167 (material and pressure testing)
• EN standards referenced for valve test methods (EN 736‑1/2, EN 1680, EN 1704/1705)

By following ISO 4437-4:2022, stakeholders ensure PE valve components for gaseous fuels meet consistent design, testing and marking requirements for safe, interoperable gas distribution systems.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 4437-4
Second edition
2022-11
Plastics piping systems for the supply
of gaseous fuels — Polyethylene
(PE) —
Part 4:
Valves
Systèmes de canalisations en plastique pour la distribution des
combustibles gazeux — Polyéthylène (PE) —
Partie 4: Robinets
Reference number
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
3.1 General . 2
3.2 Terms relating to design . 3
4 Symbols and abbreviations .3
5 Material. 3
5.1 Material for polyethylene parts . . 3
5.2 Material for non-polyethylene parts . 4
5.2.1 General . 4
5.2.2 Metal parts . 4
5.2.3 Sealing materials . 4
5.2.4 Greases and lubricants . 4
5.2.5 Assembly. 4
6 General characteristics . 5
6.1 Appearance of the valve . 5
6.2 Colour . 5
6.3 Design . 5
6.3.1 General . 5
6.3.2 Valve body . 5
6.3.3 Valve ends . 5
6.3.4 Operating device. 5
6.3.5 Seals . 5
7 Geometrical characteristics . 5
7.1 General . 5
7.2 Measurement of dimensions . 6
7.3 Dimensions of spigot ends for valves. 6
7.4 Dimensions of valves with electrofusion sockets . 6
7.5 Dimensions of the operating device . 6
8 Mechanical characteristics of assembled valves . 6
8.1 General . 6
8.2 Requirements . 6
8.2.1 General . 6
8.2.2 Air flow rate . 13
9 Physical characteristics .13
9.1 Conditioning.13
9.2 Requirements . 14
10 Performance requirements . .14
11 Technical file .14
12 Marking . .15
12.1 General . 15
12.2 Minimum required marking . 15
12.3 Additional marking. 16
13 Delivery conditions .16
Annex A (normative) Determination of the leaktightness of seat(s) and packing .17
iii
Annex B (normative) Test method for leaktightness and ease of operation after tensile
loading .19
Bibliography .21
iv
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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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 7, Valves and auxiliary equipment of plastics materials.
This second edition cancels and replaces the first edition (ISO 4437-4:2015), which has been technically
revised.
The main changes are as follows:
— PE 100-RC type materials with enhanced resistance to slow crack growth have been added;
— an improved description of the leaktightness test has been given. Annex B has been added to
describe the leaktightness test after the tensile test, following the withdrawal of ISO 10933;
— test methods have been updated including new methods for PE 100-RC materials.
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.
v
Introduction
This document specifies the requirements for a piping system and its components made from
polyethylene (PE) and intended to be used for the supply of gaseous fuels.
Requirements and test methods for material and components, other than valves, are specified in
ISO 4437-1, ISO 4437-2 and ISO 4437-3.
[2]
Characteristics for fitness for purpose are covered in ISO 4437-5. CEN/TS 1555-7 gives guidance for
[1]
assessment of conformity. Recommended practice for installation is given in ISO/TS 10839 .
This document covers the characteristics of valves.
The ISO 4437 series covers a range of maximum operating pressures and gives requirements concerning
colours. 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 regulations
and installation practices or codes.
vi
INTERNATIONAL STANDARD ISO 4437-4:2022(E)
Plastics piping systems for the supply of gaseous fuels —
Polyethylene (PE) —
Part 4:
Valves
1 Scope
This document specifies the characteristics of valves made from polyethylene (PE) for piping systems
in the field of the supply of gaseous fuels.
It is applicable to unidirectional and bi-directional isolating valves with spigot ends or electrofusion
sockets intended to be fused with PE pipes or fittings conforming to ISO 4437−2 and ISO 4437-3
respectively.
Valves made from materials other than PE, designed for the supply of gaseous fuels conforming to the
relevant standards can be used in PE piping systems according to ISO 4437 series, provided that they
have PE connections for butt fusion or electrofusion ends, including integrated material transition
joints, conforming to ISO 4437-3.
It also specifies the test parameters for the test methods referred to in this document.
In conjunction with parts 1, 2, 3 and 5 of the ISO 4437 series, this document is applicable to PE valves,
their joints and to 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 reference temperature of
20 °C for design purposes;
NOTE 1 For the purpose of this document and the references to ISO 8233, MOP is considered to be nominal
pressure.
b) an operating temperature between −20 °C to 40 °C.
NOTE 2 For operating temperatures between 20 °C and 40 °C, derating coefficients are defined in ISO 4437-5.
This document covers valve bodies designed for connection with pipes with a nominal outside diameter
d ≤ 400 mm.
n
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.
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, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of
the resistance to internal pressure — Part 1: General method
ISO 1167-4, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of
the resistance to internal pressure — Part 4: Preparation of assemblies
5 2
1) 1 bar = 0,1 MPa =10 Pa; 1 MPa = 1 N/mm .
ISO 3126, Plastics piping systems — Plastics components — Determination of dimensions
ISO 3127, Thermoplastics pipes — Determination of resistance to external blows — Round-the-clock
method
ISO 4437-1, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 1: General
ISO 4437-2, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 2: Pipes
ISO 4437-3, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 3: Fittings
ISO 4437-5, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 5: Fitness
for purpose of the system
ISO 8233, Thermoplastics valves — Torque — Test method
ISO 11357-6, Plastics — Differential scanning calorimetry (DSC) — Part 6: Determination of oxidation
induction time (isothermal OIT) and oxidation induction temperature (dynamic OIT)
ISO 16010, Elastomeric seals — Material requirements for seals used in pipes and fittings carrying gaseous
fuels and hydrocarbon fluids
ISO 17778, Plastics piping systems — Fittings, valves and ancillaries — Determination of gaseous flow
rate/pressure drop relationships
EN 736-1, Valves — Terminology — Part 1: Definition of types of valves
EN 736-2, Valves — Terminology — Part 2: Definition of components of valves
EN 1680, Plastics piping systems — Valves for polyethylene (PE) piping systems — Test method for
leaktightness under and after bending applied to the operating mechanisms
EN 1704, Plastics piping systems — Thermoplastics valves — Test method for the integrity of a valve after
temperature cycling under bending
EN 1705, Plastics piping systems — Thermoplastics valves — Test method for the integrity of a valve after
an external blow
EN 12100, Plastics piping systems — Polyethylene (PE) valves — Test method for resistance to bending
between supports
EN 12119, Plastics piping systems — Polyethylene (PE) valves — Test method for resistance to thermal
cycling
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4437-1, EN 736-1, EN 736-2
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 General
3.1.1
external leaktightness
leaktightness of the valve body enveloping the space containing the gas, with respect to the atmosphere
3.1.2
internal leaktightness
leaktightness between the inlet and the outlet of the valve, with the valve in the closed position
3.1.3
leakage
emission of gas from a valve body, or any component of a valve
3.1.4
valve body
main part of a valve which consists of an operating stop system and contains the obturator, seat(s),
stem(s) or shaft(s) and packing seals, and provides the terminal ends for connection to the PE pipe/
fittings as applicable
3.1.5
operating device
part of a valve for connection with the operating key which allows the opening and the closing of the
valve
3.2 Terms relating to design
3.2.1
full bore valve
valve with a flow section equal to or greater than 80 % of the section corresponding to the nominal
inside diameter of the body end port
[SOURCE: EN 736-3:2008]
3.2.2
clearway valve
valve designed to have an unobstructed flow way, which allows for the passage of a theoretical sphere
with a diameter that is not less than the nominal inside diameter of the body end port
[SOURCE: EN 736-3:2008]
3.2.3
reduced bore valve
valve with a flow section equal to or greater than 36 % of the section corresponding to the nominal
inside diameter of the body end port and which does not correspond to the full bore valve
[SOURCE: EN 736-3:2008]
4 Symbols and abbreviations
For the purposes of this document, the symbols and abbreviated terms given in ISO 4437-1 apply.
5 Material
5.1 Material for polyethylene parts
The PE compound from which the valve body with spigot or electrofusion socket ends is made, shall be
virgin material conforming to ISO 4437-1.
The other components of the valve made in PE shall be made only from material conforming to
ISO 4437-1.
5.2 Material for non-polyethylene parts
5.2.1 General
All components shall conform to the relevant ISO standard(s). Alternative standards may be applied in
cases where the suitable ISO standard(s) do not exist. In all cases, fitness for purpose of the components
shall be demonstrated.
The materials and the constituent elements used in making the valve (including elastomers, greases
and any metal parts as may be used) shall be as resistant to the external and internal environments
as the other elements of the piping system, and shall have an expected lifetime under the following
conditions at least equal to that of the PE pipes conforming to ISO 4437-2, with which they are intended
to be used:
a) during storage;
b) under the effect of the gas conveyed therein;
c) with respect to the service environment and operating conditions.
The requirements for the level of material performance of non-polyethylene parts shall be at least as
stringent as that of the PE compound for the piping system. Reworked materials shall not be used for
stress-bearing polymeric parts.
Other materials used in valves in contact with the PE pipe shall not adversely affect pipe performance
or initiate stress cracking.
The valve manufacturer shall ensure that any transition joint between polyethylene and non-
polyethylene parts and the valve body fulfil the requirements of ISO 4437-3.
5.2.2 Metal parts
All metal parts susceptible to corrosion shall be adequately protected, providing this is necessary for
the durability and function of the system.
When dissimilar metallic materials are used which can be in contact with moisture, steps shall be taken
to avoid the possibility of galvanic corrosion.
5.2.3 Sealing materials
Elastomeric seals shall conform to ISO 16010.
If other sealing materials are used, they need to be proven for gas supply systems.
5.2.4 Greases and lubricants
Greases or lubricants shall not exude onto fusion areas and shall not affect the long-term performance
of the valve materials.
5.2.5 Assembly
Ancillary components of valves shall be assembled according to manufacturer’s procedures and any
component used in the assembly shall not prevent conformity of the valve to this document.
6 General characteristics
6.1 Appearance of the valve
When viewed without magnification, the internal and external surfaces of valves shall be smooth, clean
and shall have no scoring, cavities or other surface defects to an extent that would prevent conformity
to this document.
No component of the valve shall show any signs of damage, scratches, pitting, bubbles, blisters,
inclusions or cracks to an extent that would prevent conformity of the valves to the requirements of
this document.
6.2 Colour
The colour of the PE parts of valves shall be either black, yellow or orange.
6.3 Design
6.3.1 General
The maximum operating pressure (MOP) of the valve shall be defined by the manufacturer according to
the design standard dimension ratio (SDR), design coefficient and material classification.
6.3.2 Valve body
The valve body shall be such that it cannot be dismantled.
An operating stop system shall be provided at the fully open and closed positions.
6.3.3 Valve ends
PE spigot ends or electrofusion sockets shall conform to the requirements of ISO 4437-3.
6.3.4 Operating device
The operating device shall be integral with or connected to the stem in such a way that disconnection is
impossible without special equipment.
The valve shall close by turning the operating device clockwise. For a quarter-turn valve, the position of
the obturator shall be clearly indicated on the top side of the operating device.
It is recommended that the position of the obturator be marked on the access point for a quarter turn
valve.
Stops shall be provided at the fully open and closed positions.
6.3.5 Seals
The seals shall be mounted in a manner as to be resistant to normally occurring mechanical loads, see
5.2.3. Creep and cold flow effects shall be taken into account. Any mechanism that puts a loading on the
seals shall be permanently locked. Line pressure shall not be used as the sole means of seal activation.
7 Geometrical characteristics
7.1 General
Each valve shall be characterized by its dimensions and associated end connections.
7.2 Measurement of dimensions
The dimensions of the valve shall be measured in accordance with ISO 3126 and rounded to the next
0,1 mm. In case of dispute, the measurement shall not be made less than 24 h after manufacture, and
after being conditioned for at least 4 h at (23 ± 2) °C.
Additionally, for spigot end valves provided with temporary supports, perform dimensional
measurement at least 1 h after removal of the supports.
Indirect measurement at the stage of production is allowed at shorter time periods providing evidence
is shown of correlation.
7.3 Dimensions of spigot ends for valves
2)
The dimensions of spigot ends shall conform to ISO 4437-3:— , Table 3, up to and including d 400 mm.
n
7.4 Dimensions of valves with electrofusion sockets
The dimensions of electrofusion sockets shall conform to ISO 4437-3:—, Table 1, up to and including d
n
400 mm.
7.5 Dimensions of the operating device
For a quarter-turn valve, the dimension of the operating devices shall be designed so it can be operated
+05,
with a (50 ) mm square socket, (40 ± 2) mm depth.
[3]
NOTE For a multi-turn operated valve, attention is drawn to the requirements specified in ISO 5210 .
8 Mechanical characteristics of assembled valves
8.1 General
All tests shall be carried out on valves assembled with pipe conforming to ISO 4437-2 from the same
SDR as the SDR of the valve spigots, in accordance with the technical instructions of the manufacturer
and taking into account the extreme conditions of utilization described in ISO 4437-5.
NOTE The properties of an assembled valve depend on the properties of the pipes and the valve and on the
conditions of their installation (i.e. geometry, temperature, type, method of conditioning, assembly and fusion
procedures).
8.2 Requirements
8.2.1 General
When tested in accordance with the test methods as specified in Table 1 using the indicated parameters,
the valves shall have mechanical characteristics conforming to the requirements given in Table 1.
Unless otherwise specified by the applicable test method, the test pieces shall be conditioned at
(23 ± 2) °C before testing in accordance with Table 1.
2) Under preparation. Stage at the time of publication: ISO/DIS 4437-3:2022.
Table 1 — Mechanical characteristics
Test parameters
Characteristic Requirements Test method
Parameter Value
a
Hydrostatic No failure during the Conditioning time Shall conform to ISO 1167-1
strength test period of any test ISO 1167-1
and
g
(20 °C, 100 h) piece
b
Number of test pieces 3
ISO 1167-4
Type of test Water-in-water
Circumferential PE 80 10,0 MPa
i
(hoop) stress :
PE 100 12,0 MPa
or PE
100-RC
Test period 100 h
Test temperature 20 °C
a
Hydrostatic No failure during the Conditioning time Shall conform to ISO 1167-1
strength test period of any test ISO 1167–1
and
g c
(80 °C, 165 h) piece
b
Number of test pieces 3
ISO 1167-4
Type of test Water-in-water
Circumferential PE 80 4,5 MPa
i
(hoop) stress :
PE 100 5,4 MPa
or PE
100-RC
Test period 165 h
Test temperature 80 °C
a
The valves shall not be pressurized within 24 h after fusion.
b
The number of test pieces given indicate the numbers required to establish a value for the characteristic described
in the table. The number of test pieces required for factory production control and process control should be listed in the
[2]
manufacturer’s quality plan. For guidance, see CEN/TS 1555-7 .
c
Only brittle failures shall be taken into account. If a ductile failure occurs before 165 h, the test may be repeated at a
lo
...