prEN ISO 11301-1

SLOVENSKI STANDARD
01-maj-2025
Cevni sistemi za obnovo podzemnih omrežij za oskrbo s plinom - 1. del: Polietilen
(PE) (ISO/DIS 11301-1:2025)
Piping systems for rehabilitation of underground gas supply networks - Part 1:
Polyethylene (PE) material (ISO/DIS 11301-1:2025)
Rohrleitungssysteme für die Sanierung von erdverlegten Gasversorgungsnetzwerken -
Teil 1: Werkstoff Polyethylen (PE) (ISO/DIS 11301-1:2025)
Systèmes de canalisations pour la réhabilitation des réseaux de distribution de gaz
enterrés - Partie 1: Matériau Polyéthylène (PE) (ISO/DIS 11301-1:2025)
Ta slovenski standard je istoveten z: prEN ISO 11301-1
ICS:
83.140.30 Polimerne cevi in fitingi za Plastics pipes and fittings for
snovi, ki niso tekočine non fluid use
91.140.40 Sistemi za oskrbo s plinom Gas supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 11301-1
ISO/TC 138/SC 8
Piping systems for rehabilitation
Secretariat: JISC
of underground gas supply
Voting begins on:
networks —
2025-02-24
Part 1:
Voting terminates on:
2025-05-19
Polyethylene (PE) material
Systèmes de canalisations pour la réhabilitation des réseaux de
distribution de gaz enterrés —
Partie 1: Matériau Polyéthylène (PE)
ICS: 75.200; 23.040.20; 23.040.45
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
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Reference number
ISO/DIS 11301-1:2025(en)
DRAFT
ISO/DIS 11301-1:2025(en)
International
Standard
ISO/DIS 11301-1
ISO/TC 138/SC 8
Piping systems for rehabilitation
Secretariat: JISC
of underground gas supply
Voting begins on:
networks —
Part 1:
Voting terminates on:
Polyethylene (PE) material
Systèmes de canalisations pour la réhabilitation des réseaux de
distribution de gaz enterrés —
Partie 1: Matériau Polyéthylène (PE)
ICS: 75.200; 23.040.20; 23.040.45
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
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Published in Switzerland Reference number
ISO/DIS 11301-1:2025(en)
ii
ISO/DIS 11301-1:2025(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
3.1 General .2
3.2 Terms related to techniques .4
3.3 Terms related to characteristics.6
3.4 Terms related to product stages .9
3.5 Terms related to materials .9
3.6 Terms related to Service conditions .10
3.7 Terms related to Joints .10
4 Symbols and abbreviated terms.11
4.1 Symbols .11
4.2 Abbreviated terms .11
5 Pipes .12
5.1 Materials . 12
5.2 General characteristics . 12
5.3 Material characteristics . 12
5.4 Geometric characteristics . 12
5.5 Mechanical characteristics . 13
5.6 Physical characteristics . 13
5.7 Jointing. 13
5.8 Marking . 13
5.9 Regional requirements for pipes .14
6 Fittings . 14
6.1 Materials .14
6.2 Marking .14
6.3 Regional requirements for fittings .14
7 Ancillary components . 14
7.1 Requirements .14
7.2 Regional requirements for ancillary components .14
8 Fitness for purpose .15
8.1 Materials . 15
8.2 General characteristics . 15
8.3 Geometric characteristics . 15
8.4 Mechanical characteristics . 15
8.5 Sampling .16
8.6 Regional requirements for fitness for purpose .16
9 Installation practice .16
9.1 Preparatory work .16
9.2 Storage, handling and transport of pipes and fittings .16
9.3 Equipment .17
9.3.1 General .17
9.3.2 Butt fusion equipment and de-beading equipment .17
9.3.3 Pipe skids/rollers . .17
9.3.4 Winching and rod-pulling equipment . .18
9.3.5 Pipe entry guides .18
9.3.6 Electrofusion equipment .18
9.3.7 Inspection equipment .18
9.3.8 Lifting equipment .18

iii
ISO/DIS 11301-1:2025(en)
9.4 Installation .19
9.4.1 General .19
9.4.2 Safety precautions .19
9.4.3 Simulated installations .19
9.5 Process-related inspection and testing . 20
9.6 Pipe end termination . 20
9.7 Reconnection to the existing pipeline system . 20
9.8 Final inspection and testing . 20
9.9 Documentation .21
Annex A (normative) Specific requirements applicable for Lining with Continuous pipes .22
Annex B (normative) Specific requirements applicable for Lining with Close-fit pipes .23
Annex C (normative) Specific requirements for Trenchless replacement techniques - pipe
bursting, pipe extraction, HDD and impact moling .27
Annex D (normative) Layered pipes .32
Annex E (normative) Factory-folded heat-reverted polyethylene (PE) pipe — Determination of
memory ability .33
Annex F (informative) Pipe design considerations particular to pipe bursting and pipe
extraction .35
Annex G (informative) Pipe design considerations particular to HDD .37
Bibliography .39

iv
ISO/DIS 11301-1:2025(en)
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 on 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 the following URL:
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 8, Rehabilitation of pipeline systems.
For piping systems made from polyethylene (PE) material, this document replaces the related content,
including requirements, of the system standards:
ISO 11299-1, -2, -3 and ISO 21225-1, -2.
Once this part of ISO 11301-1 has been published, the above mentioned replaced standards will be
withdrawn.
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
ISO/DIS 11301-1:2025(en)
Introduction
This document is a part of a System Standard for piping systems of various materials used for the
rehabilitation of existing pipelines in a specified application area. System Standards for rehabilitation deal
with the following applications:
— ISO 11300: Piping systems for rehabilitation of underground drains, sewers and water supply networks;
— ISO 11301: Piping systems for rehabilitation of underground gas supply networks.
The System Standards ISO 11300 and ISO 11301 are subdivided into parts covering a specific material per
pipe system.
ISO 11300 is subdivided into four parts:
— Part 1: Polyethylene (PE) material;
— Part 2: Thermoset composite materials;
— Part 3: Polyvinyl chloride (PVC-U) material;
— Part 4: Thermoplastic composite materials;
ISO 11301 currently consists of two parts:
— Part 1: Polyethylene (PE) material (this document);
— Part 5: Polyamide (PA-U) material (under development)
These System Standards cover various techniques for renovation and trenchless replacement. Furthermore,
they are distinguished from those for conventionally installed plastics piping systems by the requirement
to verify certain characteristics in the “as-installed” condition, after site processing. This is in addition to
specifying requirements for piping system components “as manufactured”.
A consistent structure of clause headings has been adopted for all parts of ISO 11300 and ISO 11301, in order
to facilitate direct comparisons across renovation technique families.
Figure 1 shows the clause structure and the relationship between ISO 11300 and ISO 11301.
[1]
For complementary information, see ISO 11295 .
System Standard ISO 11301-1 covers the content and replaces, for PE pipe systems, existing System
Standards for the rehabilitation of existing gas supply networks:
— The ISO 11299 series: Plastics piping systems for renovation of underground gas supply networks;
— The ISO 21225 series: Plastics piping systems for the trenchless replacement of underground pipeline
networks.
vi
ISO/DIS 11301-1:2025(en)
Figure 1 — Format of the rehabilitation system standards

vii
DRAFT International Standard ISO/DIS 11301-1:2025(en)
Piping systems for rehabilitation of underground gas supply
networks —
Part 1:
Polyethylene (PE) material
1 Scope
This document specifies requirements and test methods for pipes and fittings which are part of piping
systems for the rehabilitation by means of renovation and trenchless replacement of underground gas
supply networks.
It is applicable to polyethylene (PE) pipes, fittings and assemblies, as manufactured and as installed. It is not
applicable to the existing pipeline.
It is applicable to technique families for renovation:
— lining with continuous pipes;
— lining with close-fit pipes;
and technique families for trenchless replacement:
— pipe bursting and pipe extraction;
— horizontal directional drilling and impact moling.
and intended to be used at an operating temperature of 20 °C as the reference temperature.
NOTE For applications operating at constant temperatures greater than 20 °C and up to 40 °C, see ISO 4437-5:2024,
Annex A.
This document is applicable to:
— PE solid wall single layered pipes (nominal outside diameter, d ), including any identification stripes;
n
— PE pipes with co-extruded layers on either or both the outside and inside of the pipe (total outside
diameter, d ), as specified in Annex D, where all layers have the same MRS rating.
n
Furthermore, when used with lining with continuous pipes and trenchless replacement this document is
applicable to:
— PE coated pipes (outside diameter, d ) having a peelable, contiguous, thermoplastics additional layer on
n
the outside of the pipe (“coated pipe”), as specified in Annex D.
When used with lining with close-fit lining pipes, the lining pipe is reduced in the factory or on site to provide
a close-fitting independent or interactive pressure pipe liner.
This document is applicable to jointing by means of butt fusion and electrofusion and to fabricated and
injection-moulded fittings and mechanical connections of PE.
This document is not applicable to push-fit jointed discrete pipes assembled as part of the trenchless
installation process.
ISO/DIS 11301-1:2025(en)
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 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 4437-2, 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 4437-4, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 4: Valves
ISO 4437-5:2024, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 5: Fitness
for purpose of the system
ISO 12176-1, Plastics pipes and fittings — Equipment for fusion jointing polyethylene systems — Part 1: Butt fusion
ISO 12176-2, Plastics pipes and fittings — Equipment for fusion jointing polyethylene systems — Part 2:
Electrofusion
ISO 16010, Elastomeric seals — Material requirements for seals used in pipes and fittings carrying gaseous fuels
and hydrocarbon fluids
EN 682, Elastomeric seals — Material requirements for seals used in pipes and fittings carrying gas and
hydrocarbon fluids
EN 1555-1, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 1: General
EN 1555-2, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 2: Pipes
EN 1555-3, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 3: Fittings
EN 1555-4, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 4: Valves
EN 1555-5:2021, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 5: Fitness
for purpose of the system
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
pipeline system
interconnecting pipe network for the conveyance of fluids
3.1.2
rehabilitation
measures for restoring or upgrading the performance of existing pipeline systems (3.1.1), including renovation
(3.1.3), repair (3.1.4) and replacement (3.1.5)

ISO/DIS 11301-1:2025(en)
3.1.3
renovation
work incorporating all or part of the original fabric of the pipeline, by means of which its current performance
is improved
3.1.4
repair
rectification of local damage
3.1.5
replacement
construction of a new pipeline, on or off the line of an existing pipeline, where the function of the new pipeline
system (3.1.1) incorporates that of the old
3.1.6
trenchless replacement
replacement (3.1.5) without opening trenches other than small excavations to provide access for the
particular technique and for service and lateral connections
3.1.7
maintenance
routine work undertaken to ensure the existing performance of an asset
3.1.8
rehabilitation pipe
PE pipe applied for renovation or trenchless replacement purposes
3.1.9
lining pipe
pipe for renovation purposes prior to any site processing
3.1.10
liner
lining pipe (3.1.9) after installation
3.1.11
lining system
lining pipe (3.1.9) and all relevant fittings for insertion into an existing pipeline for the purposes of
renovation (3.1.3)
3.1.12
renovated pipeline system
existing pipeline system (3.1.1) plus the installed lining system (3.1.11) used to renovate it, as well as any
annular filler (3.1.17) used
3.1.13
replacement pipe
new pipe installed for rehabilitation purposes
3.1.14
replacement system
replacement pipe and all relevant fittings for trenchless replacement on or off an existing pipeline for the
purposes of rehabilitation
3.1.15
characteristic
property, dimension or other feature of a material or component
3.1.16
annular filler
material for grouting (3.1.18) annular space between existing pipeline and lining system (3.1.11)

ISO/DIS 11301-1:2025(en)
3.1.17
grouting
process of filling voids around the lining system (3.1.11)
3.1.18
system test pressure
STP
either hydrostatic-or air pressure, or both applied to the installed pipeline system in order to ensure its
integrity and leaktightness
3.1.19
simulated installation
installation of a lining system (3.1.11) into a simulated host pipeline (3.1.18), using representative equipment
and processes, to provide samples for testing which are representative of an actual installation
3.1.20
simulated host pipeline
section of pipeline, which is not part of an operational network, but which replicates the environment of an
operational network
3.1.21
technique family
group of rehabilitation techniques which are considered to have common characteristics for standardization
purposes
3.1.22
coated pipe
pipe with a peelable, contiguous thermoplastic additional layer on the outside of the pipe
3.1.23
solid wall single layered pipe
pipe with smooth internal and external surface, extruded from the same compound throughout the wall
3.1.24
pipe with co-extruded layers
pipe with smooth internal and external surface, having co-extruded layers on either or both the outside and
inside of the pipe, where all layers have the same MRS rating
3.1.25
interactive pressure pipe liner
liner (3.1.10) which relies on the existing pipeline for some measure of radial support in order to resist
without failure all applicable internal loads throughout its design life
3.1.26
type testing
testing performed to prove that a material, component, joint or assembly is capable of conforming to the
requirements given in the applicable standard
3.1.27
CCTV
system comprised of cameras, recorders, interconnections and displays that are used to inspect pipelines
3.2 Terms related to techniques
The various techniques for rehabilitation of underground gas supply networks, within the scope of pipeline
rehabilitation techniques generally, are shown schematically in Figure 2. For definitions of standardized
renovation techniques shown in Figure 2, but outside the scope of this document, see ISO 11295.

ISO/DIS 11301-1:2025(en)
a
(This document is applicable, for pipe systems made from PE materials.)
Figure 2 — Technique families for rehabilitation of underground gas supply networks using plastics
pipes, within the scope of pipeline rehabilitation techniques
3.2.1
lining with continuous pipes
lining with pipe made continuous prior to insertion, where the diameter of the lining pipe remains unchanged
3.2.2
lining with close-fit pipes
lining with a continuous pipe, of which the cross-section is reduced to facilitate installation and reverted
after installation to provide a close fit to the existing pipe
Note 1 to entry: For the reduction in cross-section, the following are the two options:
— reduction in the pipe manufacturing plant: the pipe is usually supplied coiled on a reel, from which it is directly
inserted;
— reduction on site: the pipe is usually fed through the reduction equipment and simultaneously inserted in one
continuous string.
3.2.3
close fit
situation of the outside of the installed liner relative to the inside of the existing pipeline, which may either
be an interference fit or include a small annular gap resulting from shrinkage and tolerances only

ISO/DIS 11301-1:2025(en)
3.2.4
close-fit pipe
continuous lining pipe (3.1.9) of thermoplastic material reshaped or otherwise expanded after insertion to
achieve a close fit to the existing pipeline
3.2.5
pipe bursting
on the line replacement method in which an existing pipe is broken by longitudinal splitting or brittle
fracture, using a mechanically applied force from within, where the pipe fragments are forced into the
surrounding ground and a new pipe of the same, smaller or larger diameter, is simultaneously pulled in
3.2.6
bursting head
tool that can crack or split the existing pipe material
Note 1 to entry: Brittle pipe materials such as clay or grey cast iron crack. Ductile pipe materials such as ductile iron,
steel or PVC-U split.
3.2.7
pipe extraction
on the line replacement method in which an existing pipeline is extracted by pulling or pushing and replaced
with a new pipe of the same, smaller or larger diameter, which is simultaneously pulled or pushed in
3.2.8
horizontal directional drilling
HDD
off the line replacement method in which a pilot bore is drilled using a steerable drilling head connected to
flexible rods and then the bore is enlarged by reamers up to the diameter required for the pipe or pipes to be
subsequently pulled/pushed into place
3.2.9
impact moling
off the line replacement method in which pipes are pulled in behind a pneumatically powered soil
displacement hammer
3.3 Terms related to characteristics
3.3.1
nominal size
DN
numerical designation of the size of a component related to the inside or 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.
[SOURCE: ISO 4427-1:2019, 3.1.1, modified to include inside diameter as option]
3.3.2
nominal size DN/OD
DN/OD
nominal size, related to the outside diameter
3.3.3
nominal outside diameter
d
n
specified outside diameter, in millimetres, assigned to a nominal size DN/OD (3.3.2)
Note 1 to entry: For thermoplastics solid-wall components, the value of nominal outside diameter is identical to the
minimum mean outside diameter, d , defined in 3.3.5.
em,min
ISO/DIS 11301-1:2025(en)
3.3.4
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) and rounded to the next greater 0,1 mm
[SOURCE: ISO 4437-1:2024, 3.1.4]
3.3.5
minimum mean outside diameter
d
em,min
minimum value of the mean outside diameter as specified for a given nominal size
[SOURCE: ISO 4437-1: 2024, 3.1.5]
3.3.6
wall thickness
e
value of the measurement of the wall thickness at any point around the circumference of a component
3.3.7
mean wall thickness
e
m
arithmetic mean of a number of measurements of the wall thickness, regularly spaced around the
circumference and in the same cross-section of a component, including the measure minimum and the
maximum measured values of the wall thickness in that cross-section
[SOURCE: ISO 4437-1:2024, 3.1.12]
3.3.8
minimum wall thickness at any point
e
min
minimum value of the wall thickness at any point around the circumference of a component, as specified
[SOURCE: ISO 4437-1:2024, 3.1.10]
3.3.9
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 different parts of the ISO 4437 series, the value of
nominal wall thickness, e , is identical to the specified minimum wall thickness at any point, e .
n min
[SOURCE: ISO 4437-1:2024, 3.1.3]
3.3.10
nominal thickness of the coating
e
coating
arithmetic mean of a number of measurements of the coating thickness around the circumference and in the
same cross-section of a component
3.3.11
standard dimension ratio
SDR
numerical designation of a pipe series, which is a convenient round number, approximately equal to the
dimension ratio of the nominal outside diameter, d (3.3.3) (3.3.3), and the nominal wall thickness, e (3.3.9)
n n
[SOURCE: ISO 4437-1:2024, 3.1.6]

ISO/DIS 11301-1:2025(en)
3.3.12
internal pressure resistance
capability to withstand internal pressurization by water or gas
3.3.13
ring stiffness
resistance of a pipe to diametric deflection in response to external loading applied along one longitudinal
diametric plane
Note 1 to entry: This definition applies to both long and short-term values.
3.3.14
out-of-roundness
difference between the measured maximum and the measured minimum outside diameter in the same
cross-sectional plane of the pipe
3.3.15
minimum bending radius
minimum radius at any point throughout the length of the pipeline, measured to the longitudinal axis of the pipe
Note 1 to entry: This is usually expressed as a multiple of the pipe diameter.
3.3.16
lower confidence limit of the predicted hydrostatic strength
σ
LPL
quantity, with the dimensions of stress, which represents the 97,5 % lower confidence limit of the predicted
hydrostatic strength at a temperature θ and time t
Note 1 to entry: It is expressed in megapascals.
3.3.17
melt mass-flow rate
MFR
value relating to the viscosity of the molten material at a specified temperature and load
Note 1 to entry: It is expressed in grams per 10 min (g/10 min)
[SOURCE: ISO 4437-1:2024, 3.3.5]
3.3.18
minimum required strength
MRS
value of the lower confidence limit of the predicted hydrostatic strength(σ ) (3.3.16) at 20 °C and 50 years,
LPL
rounded down to the next smaller value of the R10 series the or the R20 series
Note 1 to entry: Only compounds (3.2.1) with an MRS of 8 MPa or 10 MPa are specified in this document.
Note 2 to entry: The R10 series and the R20 series conform to ISO 3 .
Note 3 to entry: It is expressed in megapascals (MPa).
[SOURCE: ISO 4437-1:2024, 3.3.2]
3.3.19
oxidation induction time
OIT
relative measure of a stabilized material’s resistance to oxidative decomposition, determined by the
calorimetric measurement of the time interval to the onset of exothermic oxidation of the material at a
specified temperature in an oxygen or air atmosphere, under atmospheric pressure

ISO/DIS 11301-1:2025(en)
3.4 Terms related to product stages
The characteristics of components used for renovation and the materials from which they are made can be
considered at two distinct stages as follows.
3.4.1
“M” stage
stage as manufactured, before any subsequent site processing of components associated with the particular
renovation technique
Note 1 to entry: For pipes and fittings at the “M” stage, see Clauses 5 and 6, respectively.
3.4.2
“I” stage
stage as installed, i.e. in final configuration after any site processing of components associated with the
particular renovation technique
Note 1 to entry: For pipes and fittings at the “I” stage, see Clause 8.
3.5 Terms related to materials
3.5.1
virgin material
material in a form such as granules, powder or liquid, which has not been subjected to use or processing other
than that required for its manufacture and to which no reprocessable or recyclable material has been added
3.5.2
own reprocessable material
material prepared from clean, rejected and unused pipes, fittings, or valves, including trimmings from the
production of pipes, fittings or valves, that is reprocessed in a manufacturer’s plant after having previously
been processed by the same manufacture in the production of a component by, for example, injection
moulding or extrusion
3.5.3
external reprocessable material
material from unused products or trimmings which will be reprocessed and which were originally processed
by another manufacturer
Note 1 to entry: If a manufacturer has a production of products other than pipes and fittings, reprocessable material
from that production is considered as external reprocessable material when used for pipes or fittings production.
3.5.4
recyclable material
material prepared from used products which have been cleaned and crushed or ground
3.5.5
compound
homogeneous extruded mixture of base polymer (polyethylene) and additives, (i.e. anti-oxidants, pigments,
carbon black, UV-stabilisers and others) at a dosage level necessary for the processing and use of components
[SOURCE: ISO 4437-1:2024, 3.2.3]
3.5.7
crazing
microstructural phenomenon associated with the short-term application of tensile bending strain exceeding
the material-related critical yield strain
3.5.8
drilling mud
fluid created by mixing water and additives to facilitate drilling and transport of drill cuttings from the drill
bit to the surface
ISO/DIS 11301-1:2025(en)
3.6 Terms related to Service conditions
3.6.1
nominal pressure
PN
numerical designation, which is a convenient rounded number for reference purposes
Note 1 to entry: For plastic piping systems conveying gas, it corresponds to the maximum continuous operating
pressure, expressed in bar, which can be sustained with water at 20 °C, based on the minimum design coefficient
[SOURCE: ISO 17885:2021, 3.1.10]
3.6.2
maximum operating pressure
MOP
1)
maximum effective pressure of gas in a piping system, expressed in bar , which is allowed in continuous use
Note 1 to entry: It takes into account the physical and mechanical characteristics of the components of the piping
system (and the influence of the gas on these characteristics) and it is calculated using the following formula:
20×MRS
MOP=
C×−SDR 1
()
[SOURCE: ISO 17885:2021, 3.1.11]
3.6.3
design coefficient
C
coefficient with a value greater than 1 which takes into consideration service conditions as well as
properties of the components of a piping system other than those represented in the lower confidence limit of
the predicted hydrostatic strength
[SOURCE: ISO 4437-1:2024, 3.3.3]
3.7 Terms related to Joints
3.7.1
butt fusion joint
joint made by heating the planed ends of pipes, the matching surfaces of which are fused together by holding
them against a flat heating plate until the polyethylene material reaches fusion t
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