SIST EN ISO 21225-2:2018

Plastics piping systems for the trenchless replacement of underground pipeline networks - Part 2: Replacement off the line by horizontal directional drilling and impact moling (ISO 21225-2:2018)

This International Standard specifies requirements and test methods for pipes and fittings which are part of plastics piping systems for the trenchless replacement of various underground pipeline networks, underground non-pressure and pressure drainage and sewerage networks and underground water and gas supply networks, by means of horizontal directional drilling and impact moling.
It is applicable to polyethylene (PE) pipes and fittings, as manufactured, as well as to the installed replacement system.
This standard should be used in conjunction with standards applicable for the construction of PE pipeline systems where available.
Regarding manufactured pipe it is applicable to three different PE pipe types:
- PE solid wall single layered pipes (nominal outside diameter, dn), including any identification stripes;
- PE pipes with co-extruded layers on either or both the outside and inside of the pipe (total outside diameter, dn), as specified in Annex A, where all layers have the same MRS rating;
- PE pipes (outside diameter, dn) having a peelable, contiguous, thermoplastics additional layer on the outside of the pipe (“coated pipe”), see Annex A.
In addition it covers:
- jointing of pipe lengths by means of butt fusion joint to form continuous strings prior to installation.
- fabricated and injection-moulded fittings made of PE;

Kunststoff-Rohrleitungssysteme zur grabenlosen Erneuerung von erdverlegten Rohrleitungsnetzen - Teil 2: Erneuerung in anderer Linienführung zur Ausführung von Durchpressungen und Durchbohrungen mit einer horizontalen Bohranlage (ISO 21225-2:2018)

Dieses Dokument legt Anforderungen und Prüfverfahren für Rohre und Formstücke fest, die Teil von Kunststoff Rohrleitungssystemen sind und die mithilfe von Horizontal-Spülbohrverfahren (HDD) und Bodenverdrängungsverfahren zur grabenlosen Erneuerung von verschiedenen erdverlegten Rohrleitungs¬netzen, erdverlegten drucklosen Entwässerungsnetzen und Abwasserdruckleitungen und erdverlegten Wasser  und Gasversorgungsnetzen verwendet werden.
Es gilt für Polyethylen-(PE )Rohre und Formstücke „wie hergestellt“ sowie für das eingebaute Erneuerungssystem.
Dieses Dokument ist für die Verwendung in Verbindung mit Normen vorgesehen, die für die Konstruktion von PE Rohrleitungssystemen gelten, wenn verfügbar.
Bezüglich hergestellter Rohre gilt es für drei verschiedene PE Rohrarten:
—   einschichtige PE Vollwandrohre (Nenn Außendurchmesser dn), einschließlich jeglicher Kenn-zeichnungsstreifen;
—   PE Rohre mit koextrudierten Schichten auf entweder der Innen  oder Außenseite des Rohrs oder beiden (Gesamt Außendurchmesser dn), wie in Anhang A festgelegt, wobei alle Schichten über die gleiche erforderliche Mindestfestigkeit verfügen;
—   PE Rohre (Außendurchmesser dn) mit einer abziehbaren, zusammenhängenden, thermoplastischen Zusatzschicht auf der Rohr Außenseite („beschichtetes Rohr“), siehe Anhang A.
Zusätzlich gilt es für:
—   das Verbinden von Rohrlängen durch eine Stumpfschweißverbindung, um vor dem Einbau durchgehende Stränge zu erzeugen;
—   vorgefertigte und Spritzguss Formstücke aus PE.
Aus anderen Kunststoffen hergestellte Rohre, z. B. Polypropylen (PP), sind nicht im Anwendungsbereich dieses Dokuments enthalten.
Dieses Dokument gilt nicht für mit Steckmuffen verbundene Einzelrohre, die als Teil des grabenlosen Einbauprozesses zusammengebaut wurden.

Systèmes de canalisations en plastique pour le remplacement sans tranchée des réseaux de canalisations enterrés - Partie 2: Remplacement hors ligne par forage horizontal dirigé et fonçage par fusée (ISO 21225-2:2018)

L'ISO 21225-2:2018 spécifie les exigences et les méthodes d'essai appliqués aux tuyaux et raccords intégrés aux systèmes de canalisations en plastique pour le remplacement sans tranchée de différents réseaux de canalisations enterrés, des réseaux de branchements et de collecteurs d'assainissement enterrés sans pression et sous pression, ainsi que des réseaux d'alimentation en eau et de distribution de gaz enterrés, par forage horizontal dirigé et fonçage par fusée.
L'ISO 21225-2:2018 s'applique aux tuyaux et raccords en polyéthylène (PE), tels que fabriqués, ainsi qu'au système de remplacement, une fois installé.
L'ISO 21225-2:2018 est destiné à être utilisé conjointement avec les normes applicables à la construction de systèmes de canalisations en PE, lorsqu'elles sont disponibles.
Pour ce qui est des tuyaux fabriqués, il s'applique à trois types différents de tuyaux en PE:
-      tuyaux en PE monocouches à paroi compacte (diamètre extérieur nominal, dn), y compris les bandes d'identification éventuelles;
-      tuyaux en PE avec des couches co-extrudées à l'extérieur et/ou à l'intérieur du tuyau (diamètre extérieur total, dn), tels que spécifiés dans l'Annexe A, toutes les couches ayant la même classification MRS;
-      tuyaux en PE (diamètre extérieur, dn) comportant une couche thermoplastique supplémentaire pelable et contiguë à l'extérieur du tuyau («tuyau revêtu»), voir l'Annexe A.
En outre, l'ISO 21225-2:2018 s'applique également:
-      l'assemblage des longueurs de tuyau par soudage bout à bout pour former des trains de tuyaux continus avant l'installation;
-      les raccords en PE façonnés et moulés par injection.
Les tuyaux fabriqués dans d'autres plastiques, par exemple en polypropylène (PP), en dehors du domaine d'application du présent document.
L'ISO 21225-2:2018 n'est pas applicable aux tuyaux courts à emboîtement instantané assemblés dans le cadre du processus d'installation sans tranchée.

Cevni sistemi iz polimernih materialov za zamenjavo cevovodnih omrežij, ki so položeni v zemljo, brez izkopa - 2. del: Zamenjava linije z usmerjenim vrtanjem (ISO 21225-2:2018)

Ta mednarodni standard določa zahteve in preskusne metode za cevi in fitinge, ki so del plastičnih cevnih sistemov za zamenjavo različnih cevovodnih omrežij, ki so položeni v zemljo, podzemnih omrežij za odvodnjavanje in kanalizacijo, ki delujejo po težnostnem principu, ter podzemnih omrežij za oskrbo z vodo in s plinom brez izkopa na podlagi usmerjenega vrtanja ter udarnega kopanja.
Uporablja se za polietilenske (PE) cevi in fitinge, kot so izdelani, ter za nameščeni sistem zamenjave.
Ta standard naj bi se uporabljal v povezavi s standardi za izdelavo cevnih sistemov iz polietilenskih cevi, če so na voljo.
V zvezi z izdelanimi cevmi se uporablja za tri različne vrste polietilenskih cevi:
– PE trdne stenske cevi iz ene plasti (nazivni zunanji premer, dn) s kakršnimi koli identifikacijskimi črtami;
– PE cevi s koekstrudiranimi sloji na zunanji in/ali notranji strani cevi (celotni zunanji premer, dn), kot je opredeljeno v dodatku A, pri čemer imajo vsi sloji enako oceno MRS;
– PE prevlečene cevi (zunanji premer, dn) s termoplastičnim dodatnim slojem, ki ga je mogoče odluščiti, na zunanji strani cevi (»prevlečena cev«), glejte dodatek A.
Poleg tega zajema:
– spajanje dolžin cevi prek soležnega taljenja za oblikovanje neprekinjenega niza pred namestitvijo;
– izdelane in brizgano lite fitinge iz PE.

General Information

• Status: Published
• Publication Date: 14-Oct-2018
• ICS: 23.040.20 - Plastics pipes
• ICS: 91.140.80 - Drainage systems
• Technical Committee: PCV - Plastic pipes, fittings and valves
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 07-Jun-2018
• Due Date: 12-Aug-2018
• Completion Date: 15-Oct-2018
• Ref Project: EN ISO 21225-2:2018 - Plastics piping systems for the trenchless replacement of underground pipeline networks - Part 2: Replacement off the line by horizontal directional drilling and impact moling (ISO 21225-2:2018)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 21225-2:2018
01-november-2018
Cevni sistemi iz polimernih materialov za zamenjavo cevovodnih omrežij, ki so
položeni v zemljo, brez izkopa - 2. del: Zamenjava linije z usmerjenim vrtanjem
(ISO 21225-2:2018)
Plastics piping systems for the trenchless replacement of underground pipeline networks
- Part 2: Replacement off the line by horizontal directional drilling and impact moling (ISO
21225-2:2018)
Kunststoff-Rohrleitungssysteme zur grabenlosen Erneuerung von erdverlegten
Rohrleitungsnetzen - Teil 2: Erneuerung in anderer Linienführung zur Ausführung von
Durchpressungen und Durchbohrungen mit einer horizontalen Bohranlage (ISO 21225-
2:2018)
Systèmes de canalisations en plastique pour le remplacement sans tranchée des
réseaux de canalisations enterrés - Partie 2: Remplacement hors ligne par forage
horizontal dirigé et fonçage par fusée (ISO 21225-2:2018)
Ta slovenski standard je istoveten z: EN ISO 21225-2:2018
ICS:
23.040.20 Cevi iz polimernih materialov Plastics pipes
91.140.80 Drenažni sistemi Drainage systems
SIST EN ISO 21225-2:2018 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 21225-2:2018

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SIST EN ISO 21225-2:2018


EN ISO 21225-2
EUROPEAN STANDARD

NORME EUROPÉENNE

May 2018
EUROPÄISCHE NORM
ICS 23.040.20; 23.040.45; 91.140.80
English Version

Plastics piping systems for the trenchless replacement of
underground pipeline networks - Part 2: Replacement off
the line by horizontal directional drilling and impact
moling (ISO 21225-2:2018)
Systèmes de canalisations en plastique pour le Kunststoff-Rohrleitungssysteme zur grabenlosen
remplacement sans tranchée des réseaux de Erneuerung von erdverlegten Rohrleitungsnetzen -
canalisations enterrés - Partie 2: Remplacement hors Teil 2: Erneuerung in anderer Linienführung zur
ligne par forage horizontal dirigé et fonçage par fusée Ausführung von Durchpressungen und
(ISO 21225-2:2018) Durchbohrungen mit einer horizontalen Bohranlage
(ISO 21225-2:2018)
This European Standard was approved by CEN on 1 March 2018.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21225-2:2018 E
worldwide for CEN national Members.

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SIST EN ISO 21225-2:2018
EN ISO 21225-2:2018 (E)
Contents Page
European foreword . 3
2

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SIST EN ISO 21225-2:2018
EN ISO 21225-2:2018 (E)
European foreword
This document (EN ISO 21225-2:2018) has been prepared by Technical Committee ISO/TC 138
“Plastics pipes, fittings and valves for the transport of fluids” in collaboration with Technical Committee
CEN/TC 155 “Plastics piping systems and ducting systems” the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by November 2018, and conflicting national standards
shall be withdrawn at the latest by November 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 21225-2:2018 has been approved by CEN as EN ISO 21225-2:2018 without any
modification.


3

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SIST EN ISO 21225-2:2018

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SIST EN ISO 21225-2:2018
INTERNATIONAL ISO
STANDARD 21225-2
First edition
2018-04
Plastics piping systems for
the trenchless replacement of
underground pipeline networks —
Part 2:
Replacement off the line by horizontal
directional drilling and impact moling
Systèmes de canalisations en plastique pour le remplacement sans
tranchée des réseaux de canalisations enterrés —
Partie 2: Remplacement hors ligne par forage horizontal dirigé et
fonçage par fusée
Reference number
ISO 21225-2:2018(E)
©
ISO 2018

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SIST EN ISO 21225-2:2018
ISO 21225-2:2018(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2018
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]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

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SIST EN ISO 21225-2:2018
ISO 21225-2:2018(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms . 7
4.1 Symbols . 7
4.2 Abbreviated terms . 8
5 Design aspects . 8
6 Material selection . 8
6.1 Pipes and fittings . 8
6.2 Regional requirements for pipes and fittings . 9
6.3 Ancillary components . 9
7 Installation practice . 9
7.1 Preparatory work . 9
7.2 Storage, handling and transport . 9
7.3 Equipment .10
7.3.1 General.10
7.3.2 Inspection equipment .10
7.3.3 Lifting equipment .10
7.3.4 Butt fusion equipment and debeading equipment.10
7.3.5 Pipe skids/rollers .10
7.3.6 HDD equipment .11
7.3.7 Impact moling equipment.11
7.3.8 Electrofusion equipment .12
7.4 Installation .12
7.5 Process-related inspection and testing .13
7.6 Finishing off .13
7.7 Connection to the existing pipeline system.13
8 Fitness for purpose .14
8.1 General .14
8.2 Final inspection .14
8.3 Pressure testing .14
8.4 Disinfection .14
8.5 Documentation .15
Annex A (normative) Layered pipes .16
Annex B (informative) Pipe design considerations particular to HDD .17
Bibliography .19
© ISO 2018 – All rights reserved iii

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SIST EN ISO 21225-2:2018
ISO 21225-2:2018(E)

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.
A list of all the parts in the ISO 21225 series can be found on the ISO website.
iv © ISO 2018 – All rights reserved

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SIST EN ISO 21225-2:2018
ISO 21225-2:2018(E)

Introduction
System standards dealing with following applications are either available or in preparation for pipeline
renovation:
— The ISO 11296 series: Plastics piping systems for renovation of underground non-pressure drainage
and sewerage networks;
— The ISO 11297 series: Plastics piping systems for renovation of underground drainage and sewerage
networks under pressure;
— The ISO 11298 series: Plastics piping systems for renovation of underground water supply networks;
— The ISO 11299 series: Plastics piping systems for renovation of underground gas supply networks.
System standards dealing with all application areas are either available or in preparation for trenchless
pipeline replacement:
— The ISO 21225 series: Plastics piping systems for the trenchless replacement of underground pipeline
networks.
The system standard ISO 21225 comprises:
— Part 1: Replacement on the line by pipe bursting and pipe extraction;
— Part 2: Replacement off the line by horizontal directional drilling and impact moling (this document).
The requirements for technique families are given in ISO 21225-1 and ISO 21225-2 (this document)
[1]
respectively. For complimentary information, see ISO 11295 .
A consistent structure of clause headings has been adopted for all parts to facilitate direct comparisons
across replacement standards.
Figure 1 shows the common part and clause structure and the relationship between ISO 21255 and the
system standards for the renovation application areas.
© ISO 2018 – All rights reserved v

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SIST EN ISO 21225-2:2018
ISO 21225-2:2018(E)

Figure 1 — Technique families and clause structure
vi © ISO 2018 – All rights reserved

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SIST EN ISO 21225-2:2018
INTERNATIONAL STANDARD ISO 21225-2:2018(E)
Plastics piping systems for the trenchless replacement of
underground pipeline networks —
Part 2:
Replacement off the line by horizontal directional drilling
and impact moling
1 Scope
This document specifies requirements and test methods for pipes and fittings which are part of plastics
piping systems for the trenchless replacement of various underground pipeline networks, underground
non-pressure and pressure drainage and sewerage networks and underground water and gas supply
networks, by means of horizontal directional drilling and impact moling.
It is applicable to polyethylene (PE) pipes and fittings, as manufactured, as well as to the installed
replacement system.
This document is intended to be used in conjunction with standards applicable for the construction of
PE pipeline systems where available.
Regarding manufactured pipes it is applicable to three different PE pipe types:
— 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 A, where all layers have the same MRS rating;
n
— PE pipes (outside diameter, d ) having a peelable, contiguous, thermoplastics additional layer on the
n
outside of the pipe (“coated pipe”), see Annex A.
In addition it is applicable to:
— jointing of pipe lengths by means of butt fusion joint to form continuous strings prior to installation;
— fabricated and injection-moulded fittings made of PE.
Pipes made from other plastics, e.g. polypropylene (PP) are outside the scope of this document.
This document is not applicable to push-fit jointed discrete pipes assembled as part of the trenchless
installation process.
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 4427 (all parts), Plastics piping systems — Polyethylene (PE) pipes and fittings for water supply
ISO 4437 (all parts), Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE)
ISO 4633, Rubber seals — Joint rings for water supply, drainage and sewerage pipelines — Specification for
materials
© ISO 2018 – All rights reserved 1

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SIST EN ISO 21225-2:2018
ISO 21225-2:2018(E)

ISO 8772, Plastics piping systems for non-pressure underground drainage and sewerage — Polyethylene (PE)
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 681-1, Elastomeric seals — Material requirements for pipe joint seals used in water and drainage
applications — Part 1: Vulcanized rubber
EN 681-2, Elastomeric seals — Material requirements for pipe joint seals used in water and drainage
applications — Part 2: Thermoplastic elastomers
EN 681-3, Elastomeric seals — Material requirements for pipe joint seals used in water and drainage
applications — Part 3: Cellular materials of vulcanized rubber
EN 681-4, Elastomeric seals — Material requirements for pipe joint seals used in water and drainage
applications — Part 4: Cast polyurethane sealing elements
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 1555-5, Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) — Part 5: Fitness for
purpose of the system
EN 12201-1, Plastics piping systems for water supply, and for drainage and sewerage under pressure —
Polyethylene (PE) — Part 1: General
EN 12201-2, Plastics piping systems for water supply, and for drainage and sewerage under pressure —
Polyethylene (PE) — Part 2: Pipes
EN 12201-3, Plastics piping systems for water supply, and for drainage and sewerage under pressure —
Polyethylene (PE) — Part 3: Fittings
EN 12201-5, Plastics piping systems for water supply, and for drainage and sewerage under pressure —
Polyethylene (PE) — Part 5: Fitness for purpose of the system
EN 12666-1, Plastics piping systems for non-pressure underground drainage and sewerage — Polyethylene
(PE) — Part 1: Specifications for pipes, fittings and the system
3 Terms and definitions
For the purposes of this document the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1 General
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SIST EN ISO 21225-2:2018
ISO 21225-2:2018(E)

3.1.1
CCTV system
system comprised of cameras, recorders, interconnections and displays that are used to inspect
pipelines
3.1.2
characteristic
property, dimension or other feature of a material or component
3.1.3
coated pipe
pipe with a peelable, contiguous thermoplastic additional layer on the outside of the pipe
3.1.4
installed pipe
replacement pipe after installation
3.1.5
maintenance
routine work undertaken to ensure the continuing performance of an asset
3.1.6
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
3.1.7
pipeline system
interconnecting pipe network for the conveyance of fluids
3.1.8
rehabilitation
measures for restoring or upgrading the performance of existing pipeline systems, including renovation,
repair and replacement
3.1.9
renovation
work incorporating all or part of the original fabric of the pipeline, by means of which its current
performance is improved
3.1.10
repair
rectification of local damage
3.1.11
replacement
construction of a new pipeline, on or off the line of an existing pipeline, where the function of the new
pipeline system incorporates that of the old
3.1.12
replacement pipe
new pipe installed for rehabilitation purposes
3.1.13
replacement system
replacement pipe and all relevant fittings for trenchless replacement on or off an existing pipeline for
the purposes of rehabilitation
© ISO 2018 – All rights reserved 3

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SIST EN ISO 21225-2:2018
ISO 21225-2:2018(E)

3.1.14
solid wall single layered pipe
pipe with smooth internal and external surface, extruded from the same compound/formulation
throughout the wall
3.1.15
system test pressure
STP
pressure applied to the installed pipeline system in order to ensure its integrity and leaktightness
3.1.16
technique family
group of renovation or trenchless replacement techniques which are considered to have common
characteristics for standardization purposes
3.1.17
trenchless replacement
replacement without opening trenches other than small excavations to provide access for the particular
technique
3.2 Techniques
The various techniques for trenchless replacement of underground networks, within the scope of
pipeline rehabilitation techniques generally, are shown schematically in Figure 2.
Definitions of technique families outside the scope of this document are given in ISO 11295.
The technique families within the scope of this document are defined as follows.
3.2.1
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
3.2.2
impact moling
off the line replacement method in which pipes are pulled in behind a pneumatically powered soil
displacement hammer
4 © ISO 2018 – All rights reserved

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SIST EN ISO 21225-2:2018
ISO 21225-2:2018(E)


a
This document is applicable.
b
In scope of ISO 21225-2.
c [1]
Outside scope of ISO 21225, see ISO 11295 .
Figure 2 — Technique families for trenchless replacement of underground pipeline networks
using plastics pipes, within the scope of pipeline rehabilitation techniques
3.3 Geometrics
3.3.1
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.
3.3.2
minimum mean outside diameter
d
em,min
minimum value of the mean outside diameter as specified for a given nominal size
[SOURCE: ISO 4427-1:2007, 3.1.1.6]
© ISO 2018 – All rights reserved 5

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SIST EN ISO 21225-2:2018
ISO 21225-2:2018(E)

3.3.3
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 4427-1:2007, 3.1.1.11]
3.3.4
nominal outside diameter
d
n
specified outside diameter, in millimetres, assigned to a nominal size DN/OD
Note 1 to entry: For thermoplastics solid-wall components, the value of nominal outside diameter, is identical to
the minimum mean outside diameter, d .
em,min
[SOURCE: ISO 4427-1:2007, 3.1.1.3, modified by addition of Note 1 to entry.]
3.3.5
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
3.3.6
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
Note 1 to entry: For thermoplastics solid-wall components, the value of nominal wall thickness, e , is identical to
n
the specified minimum wall thickness at any point, e .
min
[SOURCE: ISO 4427-1:2007, 3.1.1.9, modified by addition of Note 1 to entry.]
3.3.7
out-of-roundness
difference between the measured maximum and the measured minimum outside diameter in the same
cross-sectional plane of the pipe
3.3.8
standard dimension ratio
SDR
ratio of the nominal outside diameter, d , to its nominal wall thickness, e
n n
3.3.9
wall thickness
e
value of the measurement of the wall thickness at any point around the circumference of a component
3.4 Materials
3.4.1
compound/formulation
clear
...