ISO 14531-4:2006

INTERNATIONAL ISO
STANDARD 14531-4
First edition
2006-04-01
Plastics pipes and fittings — Crosslinked
polyethylene (PE-X) pipe systems for the
conveyance of gaseous fuels — Metric
series — Specifications —
Part 4:
System design and installation guidelines
Tubes et raccords en matières plastiques — Systèmes de tubes en
polyéthylène réticulé (PE-X) pour le transport de combustibles
gazeux — Série métrique — Spécifications —
Partie 4: Lignes directrices pour la conception et l'installation du
système
Reference number
©
ISO 2006
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©  ISO 2006
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ii © ISO 2006 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 2
3 Terms and definitions. 2
4 Requirements . 5
4.1 Design . 5
4.1.1 General. 5
4.1.2 Materials . 5
4.1.3 Pressure ranges. 5
4.1.4 Minimum/maximum operating temperatures T /T . 6
min max
4.1.5 Pipes. 6
4.1.6 Pipeline components. 8
4.2 Construction. 10
4.2.1 Handling, transport and storage . 10
4.2.2 Jointing . 10
4.3 Laying . 12
4.3.1 General. 12
4.3.2 Open-trench installation . 12
4.3.3 Trenchless installation. 13
4.3.4 Stopping the gas flow. 13
5 Tests on site . 13
5.1 General. 13
5.2 Pressure test . 13
Annex A (informative) Assessment of lifetime using Miner's rule . 15
Bibliography . 16

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 14531-4 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 4, Plastic pipes and fittings for the supply of gaseous fuels.
ISO 14531 consists of the following parts, under the general title Plastics pipes and fittings — Crosslinked
polyethylene (PE-X) pipe systems for the conveyance of gaseous fuels — Metric series — Specifications:
⎯ Part 1: Pipes
⎯ Part 2: Fittings for heat-fusion jointing
⎯ Part 3: Fittings for mechanical jointing (including PE-X/metal transitions)
⎯ Part 4: System design and installation guidelines
iv © ISO 2006 – All rights reserved

Introduction
Further to the publication of International Standards for crosslinked polyethylene (PE-X) hot-water pipes, it has
become evident that the properties of PE-X, in particular its high fracture resistance and a recently established
socket and saddle fusion-jointing capability, render it suitable for use in high-performance gas-distribution
systems. The philosophy of ISO 14531 is to provide the basis for the introduction of PE-X gas pipe systems by
the specification of a performance envelope beyond that covered by existing PE standards in order to take its
application into regimes of higher operating pressures and extremes of operating temperature.
This part of ISO 14531 is therefore one part of a four-part system standard covering pipes, fittings for
heat-fusion jointing, fittings for mechanical jointing and design and installation guidelines. The content is
suitable for use by procurement authorities and distribution engineers responsible for the design, installation
and operation of pipeline systems.

INTERNATIONAL STANDARD ISO 14531-4:2006(E)

Plastics pipes and fittings — Crosslinked polyethylene (PE-X)
pipe systems for the conveyance of gaseous fuels — Metric
series — Specifications —
Part 4:
System design and installation guidelines
1 Scope
This part of ISO 14531 provides guidance for the design, construction, installation and on-site testing of PE-X
pipeline systems. The standard deals with trenchless and open-trench installation methods.
This part of ISO 14531, when used in conjunction with the other parts of ISO 14531, provides the basis for the
design, manufacture and installation of PE-X piping systems (PE-X pipes, and PE-X and PE heat-fusion fittings
and mechanical fittings) for the supply of category D and category E hydrocarbon-based fuels (see
ISO 13623) at
1)
a) maximum operating pressures (MOPs) up to and including 16 bar and
b) a maximum operating temperature of +60 °C and
c) a minimum operating temperature of
1) −50 °C
2) −35 °C
3) −20 °C.
This part of ISO 14531 provides for the jointing and installation of PE-X and PE heat-fusion fittings and
mechanical fittings to PE-X pipes within the temperature range −5 °C to +40 °C. The jointing of pipes and
fittings outside the stated temperature range should be the subject of consultation between the pipeline
operator and the pipe, fitting and equipment manufacturers.
Users of this part of ISO 14531 should be aware that useful supplementary information is given in the
standards listed in the bibliography.

5 2
1) 1 bar = 10 N/m = 100 kPa.
2 Normative references
The following referenced documents are indispensable for the application 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 4065, Thermoplastic pipes — Universal wall thickness table
ISO 8085-3, Polyethylene fittings for use with polyethylene pipes for the supply of gaseous fuels — Metric
series — Specifications — Part 3: Electrofusion fittings
ISO 9080, Plastics piping and ducting systems — Determination of the long-term hydrostatic strength of
thermoplastics materials in pipe form by extrapolation
ISO 10838 (all parts), Mechanical fittings for polyethylene piping systems for the supply of gaseous fuels
ISO/TS 10839:2000, Polyethylene pipes and fittings for the supply of gaseous fuels — Code of practice for
design, handling and installation
ISO 12162, Thermoplastics materials for pipes and fittings for pressure applications — Classification and
designation — Overall service (design) coefficient
ISO 12176-2, Plastics pipes and fittings — Equipment for fusion jointing polyethylene systems — Part 2:
Electrofusion
ISO 13623, Petroleum and natural gas industries — Pipeline transportation systems
ISO 13760, Plastics pipes for the conveyance of fluids under pressure — Miner's rule — Calculation method
for cumulative damage
ISO 14531-1:2002, Plastics pipes and fittings — Crosslinked polyethylene (PE-X) pipe systems for the
conveyance of gaseous fuels — Metric series — Specifications — Part 1: Pipes
ISO 14531-2, Plastics pipes and fittings — Crosslinked polyethylene (PE-X) pipe systems for the conveyance
of gaseous fuels — Metric series — Specifications — Part 2: Fittings for heat-fusion jointing
ISO 14531-3, Plastics pipes and fittings — Crosslinked polyethylene (PE-X) pipe systems for the conveyance
of gaseous fuels — Metric series — Specifications — Part 3: Fittings for mechanical jointing (including
PE-X/metal transitions)
EN 12007-1, Gas supply systems — Pipelines for maximum operating pressure up to and including 16 bar —
Part 1: General functional recommendations
EN 12007-2, Gas supply systems — Pipelines for maximum operating pressure up to and including 16 bar —
Part 2: Specific functional recommendations for polyethylene (MOP up to and including 10 bar)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
nominal outside diameter
d
n
numerical designation of size which is common to all components in a thermoplastics piping system other than
flanges and components designated by thread size
NOTE 1 It is a convenient round number for reference purposes.
2 © ISO 2006 – All rights reserved

NOTE 2 The nominal outside diameter expressed in millimetres is the minimum mean outside diameter d of pipe
e,min
produced in accordance with ISO 14531-1.
3.2
nominal wall thickness
e
n
nominal designation of wall thickness of a pipe in millimetres in accordance with ISO 4065
3.3
standard dimension ratio
SDR
ratio of the nominal outside diameter of a pipe to its nominal wall thickness
d
n
SDR =
e
n
NOTE The value of the SDR is selected from Table 5 in ISO 14531-1:2002.
3.4
gaseous fuel
fuel which is in a gaseous state at a temperature of +15 °C and a pressure of 1 bar
3.5
category D gaseous fuel
natural gas
NOTE Categories of gaseous and liquid fuels are defined in detail in ISO 13623.
3.6
category E gaseous fuel
LPG vapour or natural gas conveyed in association with liquid condensate
NOTE Categories of gaseous and liquid fuels are defined in detail in ISO 1362
...