SIST EN ISO 11295:2026

SLOVENSKI STANDARD
01-april-2026
Cevni sistemi iz polimernih materialov za obnovo cevovodov - Razvrstitev in
pregled strateških, taktičnih in operativnih dejavnosti (ISO 11295:2026)
Plastics piping systems used for the rehabilitation of pipelines - Classification and
overview of strategic, tactical and operational activities (ISO 11295:2026)
Rohrleitungssysteme aus Kunststoff für die Sanierung von Rohrleitungen -
Klassifizierung und Überblick über strategische, taktische und operative Aktivitäten (ISO
11295:2026)
Systèmes de canalisation en plastique destinés à la réhabilitation des réseaux enterrés -
Classification et vue d’ensemble des activités stratégiques, tactiques et opérationnelles
(ISO 11295:2026)
Ta slovenski standard je istoveten z: EN ISO 11295:2026
ICS:
23.040.01 Deli cevovodov in cevovodi Pipeline components and
na splošno pipelines in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 11295
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2026
EUROPÄISCHE NORM
ICS 23.040.20 Supersedes EN ISO 11295:2022
English Version
Plastics piping systems used for the rehabilitation of
pipelines - Classification and overview of strategic, tactical
and operational activities (ISO 11295:2026)
Systèmes de canalisation en plastique destinés à la Rohrleitungssysteme aus Kunststoff für die Sanierung
réhabilitation des réseaux enterrés - Classification et von Rohrleitungen - Klassifizierung und Überblick über
vue d'ensemble des activités stratégiques, tactiques et strategische, taktische und operative Aktivitäten (ISO
opérationnelles (ISO 11295:2026) 11295:2026)
This European Standard was approved by CEN on 1 February 2026.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye 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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11295:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 11295:2026) 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 August 2026, and conflicting national standards shall
be withdrawn at the latest by August 2026.
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.
This document supersedes EN ISO 11295:2022.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 11295:2026 has been approved by CEN as EN ISO 11295:2026 without any modification.

International
Standard
ISO 11295
Fourth edition
Plastics piping systems used for
2026-02
the rehabilitation of pipelines —
Classification and overview of
strategic, tactical and operational
activities
Systèmes de canalisation en plastique destinés à la réhabilitation
des réseaux enterrés — Classification et vue d’ensemble des
activités stratégiques, tactiques et opérationnelles
Reference number
ISO 11295:2026(en) © ISO 2026
ISO 11295:2026(en)
© ISO 2026
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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 11295:2026(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 General terms .2
3.2 Terms related to techniques .4
3.3 Terms related to service conditions .6
4 Abbreviated terms . 7
5 Pipeline rehabilitation process . 7
6 Investigation and condition assessment of the existing pipeline . 8
6.1 Performance criteria .8
6.1.1 General .8
6.1.2 Hydraulic requirements .9
6.1.3 Structural requirements .9
6.1.4 Environmental requirements .9
6.1.5 Operational requirements .10
6.2 Investigation of performance .10
6.2.1 General .10
6.2.2 Hydraulic investigation .11
6.2.3 Structural investigation . .11
6.2.4 Environmental investigation . . 12
6.2.5 Operational investigation . 12
6.3 Condition assessment . 12
6.4 Risk analysis . 13
6.5 Control measures . 13
7 Classification and characteristics of rehabilitation techniques . 14
7.1 Overview .14
7.2 Classification of renovation techniques .16
7.2.1 General .16
7.2.2 Lining with continuous pipes . .16
7.2.3 Lining with close-fit pipes .18
7.2.4 Lining with cured-in-place pipes .21
7.2.5 Lining with discrete pipes . 25
7.2.6 Lining with adhesive-backed hoses. 29
7.2.7 Lining with spirally-wound pipes . 30
7.2.8 Lining with pipe segments . 33
7.2.9 Lining with a rigidly anchored plastics inner layer . 34
7.2.10 Lining with sprayed polymeric materials . . 36
7.2.11 Lining with inserted hoses . 38
7.3 Classification of trenchless replacement techniques . 40
7.3.1 General . 40
7.3.2 Pipe bursting. 40
7.3.3 Pipe removal .43
7.3.4 Horizontal directional drilling (HDD) . 46
7.3.5 Impact moling . 49
7.3.6 Pipe jacking .51
8 Selection of rehabilitation techniques .54
8.1 General . 54
8.2 Pipeline system layout . 54
8.3 Hydraulic performance . 55
8.4 Structural performance . 56

iii
ISO 11295:2026(en)
8.4.1 General . 56
8.4.2 Non-pressure pipes . 56
8.4.3 Pressure pipes .57
8.5 Environmental impact . 60
8.6 Construction constraints .61
8.7 Project specification .61
9 Implementation of rehabilitation techniques .62
9.1 Preconstruction activities . .62
9.2 Assessment of conformity of products . 63
9.3 Inspection, storage and handling of the materials on site . 63
9.4 Application of rehabilitation technique . 63
9.4.1 Preparatory work . 63
9.4.2 Construction. 64
9.5 Acceptance control . 64
9.5.1 General . 64
9.5.2 Leaktightness testing . 64
9.5.3 Sampling . 66
9.6 Completion of the work . 66
9.6.1 Finishing off the rehabilitation work . 66
9.6.2 Lateral reinstatement . 66
9.7 Documentation of the process . 66
Bibliography . 67

iv
ISO 11295:2026(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 document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 8, Rehabilitation of pipeline systems, in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 155, Plastics piping systems and
ducting systems, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
This fourth edition cancels and replaces the third edition (ISO 11295:2022), which has been technically
revised.
The main changes are as follows:
— references have been updated;
— twelve existing definitions have been modified (3.1.3, 3.1.13, 3.1.14, 3.1.15, 3.1.16, 3.1.17, 3.1.18, 3.2.1,
3.2.2, 3.2.4, 3.2.6 and 3.3.2);
— fourteen new terms have been defined (3.1.5, 3.1.6, 3.1.7, 3.1.8, 3.1.22, 3.1.23, 3.1.24, 3.1.25, 3.2.15, 3.2.17,
3.2.18, 3.2.26, 3.2.27 and 3.2.29).
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 11295:2026(en)
Introduction
Pipeline systems are continuously required to satisfy physical, chemical, biochemical and biological
demands. These demands depend on planning, material, construction, type and period of use.
When pipeline systems become operational, they constitute a valuable asset to the network owner. For this
reason, adequate management, including monitoring the performance of the pipeline system, is common
practice. For general guidelines and requirements on asset management, ISO 55000, ISO 55001 and
ISO 55002 are applicable.
For the specific case of pipelines for water supply and wastewater collection, detailed information on the
overall management of the networks is provided by ISO 24516-1 and ISO 24516-3.
In the case of loss of performance of a pipeline system, reactive measures initially focus on improving
regular maintenance procedures, including cleaning. In case of deterioration or other serious defects, more
stringent measures to rehabilitate the pipeline become necessary.
Rehabilitation is carried out when there is a need to restore or upgrade the performance of a pipeline system.
Rehabilitation can consist of repair, renovation or replacement. In recent years, the rehabilitation of pipeline
systems has become increasingly important and will continue to be so.
This document provides information on the design process when considering rehabilitation of an existing
pipeline, in order of sequence:
a) investigation and assessment of the deficiencies of current performance of the existing pipeline;
b) determination of viable options, based on performance criteria and process-related factors;
c) specification of the selected type of technique and the required pipe material;
d) the installation;
e) testing the performance before the pipeline is put back into service.
The techniques used for the renovation and trenchless replacement of existing pipelines are classified in
technique families and the typical characteristics of each are described in general terms.
It is the responsibility of the designer to choose and design the renovation or trenchless replacement pipeline
system.
vi
International Standard ISO 11295:2026(en)
Plastics piping systems used for the rehabilitation of
pipelines — Classification and overview of strategic, tactical
and operational activities
1 Scope
This document establishes the steps of the overall process of pipeline rehabilitation, comprising:
— strategic and tactical activities:
a) investigation and condition assessment of the existing pipeline;
b) pipeline rehabilitation planning.
— operational activities:
c) project specification;
d) applications of techniques;
e) documentation of the design and application process.
This document defines general terms of pipeline rehabilitation and establishes the classification of families
of renovation and trenchless replacement techniques, with description of their respective features.
This document is applicable to underground drains and sewers and underground water and gas supply
networks.
This document does not apply to:
— new construction provided as network extensions;
— calculation methods to determine, for each viable technique, the characteristics of lining or replacement
pipe material needed to secure the desired performance of the rehabilitated pipeline;
— techniques providing non-structural pipe liners;
— techniques for repair.
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 1043-1, Plastics — Symbols and abbreviated terms — Part 1: Basic polymers and their special characteristics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1043-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp

ISO 11295:2026(en)
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 General terms
3.1.1
assessment
process, or result of this process, comparing a specified subject matter to relevant references
3.1.2
design working life
assumed period for which a structure or part of it is to be used for its intended purpose with anticipated
repair (3.1.11) and maintenance (3.1.15) but without renovation (3.1.10) or replacement (3.1.12) being
necessary
3.1.3
hazard
biological, chemical, physical or radiological agent in, or condition of, water with the potential danger to
cause harm to public health
Note 1 to entry: Condition includes quantity.
[SOURCE: EN 15975-1:2011+A1:2015, 2.6]
3.1.4
pipeline system
interconnecting pipe network for the conveyance of fluids
3.1.5
drain
conduit which conveys wastewater, surface water or other unwanted liquids, including its connections to
lateral pipes, manhole chambers (3.1.8), gullies and other network components
[SOURCE: ISO 6707-1:2020, 3.3.4.38, modified — details of connections have been added]
3.1.6
sewer
pipeline which conveys waste water, including its connections to lateral pipes, manholes (3.1.7), manhole
chambers (3.1.8) and other network components
[SOURCE: ISO 6707-1:2020, 3.3.4.41, modified — details of connections have been added]
3.1.7
manhole
opening fitted with a removable cover, which permits entry of a person to a pipeline or closed vessel
[SOURCE: ISO 6707-1:2020, 3.3.4.19]
3.1.8
manhole chamber
chamber constructed on a drain (3.1.5), sewer (3.1.6), or pipeline, with a removable cover permitting entry
of a person
[SOURCE: ISO 6707-1:2020, 3.3.4.20]
3.1.9
rehabilitation
measures for restoring or upgrading the performance of existing pipeline systems (3.1.4), including renovation
(3.1.10), repair (3.1.11) and replacement (3.1.12)

ISO 11295:2026(en)
3.1.10
renovation
work incorporating all or part of the original fabric of the pipeline, by means of which its current performance
is improved
3.1.11
repair
rectification of local damage
3.1.12
replacement
construction of a new pipeline, on or off the line of an existing pipeline, where the function of the new pipeline
system (3.1.4) incorporates that of the old
3.1.13
network extension
new construction off the line of a pipeline or a network with the aim to expand service to unserved areas
3.1.14
trenchless replacement
replacement (3.1.12) without opening trenches other than small excavations to provide access for the
particular technique and for service and lateral connections
3.1.15
maintenance
routine work undertaken to ensure the existing performance of an asset
3.1.16
independent pressure pipe liner
liner (3.2.3) capable on its own of resisting without failure all applicable internal loads throughout its design
life
Note 1 to entry: it can provide either fully-structural renovation (3.1.18) or semi-structural renovation (3.1.19) with
respect to external loading
3.1.17
interactive pressure pipe liner
liner (3.2.3) 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
3.1.18
fully-structural renovation
use of an independent pressure pipe liner (3.1.16) or non-pressure liner which is capable of resisting all
external loads irrespective of the condition of the existing pipeline
3.1.19
semi-structural renovation
use of an interactive pressure pipe liner (3.1.17) which is capable of long-term hole and gap spanning at
operational pressure
3.1.20
non-structural renovation
use of an interactive pressure pipe liner (3.1.17) which is not capable of long-term hole and gap spanning at
operational pressure
3.1.21
flow diversion
temporary isolation of the section of pipeline to be rehabilitated by the use of a temporary bypass or other
means
ISO 11295:2026(en)
3.1.22
CCTV
closed-circuit television
system comprised of cameras, recorders, interconnections and displays that are used to inspect pipelines
3.1.23
system test pressure
pressure applied to the installed pipeline system (3.1.4) in order to ensure its integrity and leaktightness
3.1.24
simulated host pipeline
section of pipeline, which is not part of an operational network, but which replicates the environment of an
operational network
3.1.25
simulated installation
installation of all or part of a lining system (3.2.4) into a simulated host pipeline (3.1.24), using representative
equipment and processes, to provide samples for testing which are representative of an actual installation
3.2 Terms related to techniques
3.2.1
technique family
grouping of rehabilitation (3.1.9) techniques which are considered to have common characteristics for
standardization purposes
3.2.2
lining pipe
pipe inserted for renovation (3.1.10) purposes prior to any site processing
3.2.3
liner
lining pipe (3.2.2) after installation
3.2.4
lining system
lining pipe (3.2.2) and all relevant fittings for insertion into an existing pipeline for the purposes of renovation
(3.1.10)
3.2.5
lining with continuous pipes
lining with pipe made continuous prior to insertion, where the diameter of the lining pipe (3.2.2) remains
unchanged
3.2.6
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 (3.2.26) to the existing pipe
3.2.7
lining with cured-in-place pipes
lining with a flexible tube impregnated with a thermosetting resin, which produces a pipe after resin cure
3.2.8
lining with discrete pipes
lining with short lengths of pipe which are jointed to form a continuous pipe one by one during insertion
3.2.9
lining with adhesive-backed hoses
lining with a reinforced hose which relies on an adhesive bond to the host pipe to provide resistance to
collapse
ISO 11295:2026(en)
3.2.10
lining with spirally-wound pipes
lining with a profiled strip, spirally wound to form a continuous pipe after installation
3.2.11
lining with sprayed polymeric materials
lining with a sprayed two-part polymeric resin material that forms a continuous pipe after resin cure
3.2.12
lining with inserted hoses
lining with a reinforced hose which is either permanently shaped or re-rounded after installation by the
application of an internal pressure
3.2.13
lining with a rigidly anchored plastics inner layer
lining with a single rigid annulus of structural cementitious grout formed between a plastics layer and the
host pipe, where the plastics layer is permanently anchored in the grout
3.2.14
lining with pipe segments
lining with prefabricated segments bonded to the existing pipe, which either have longitudinal joints and
cover the whole of the pipe circumference, or cover only part of the circumference
3.2.15
replacement pipe
new pipe installed for rehabilitation purposes
3.2.16
pipe bursting
on-the-line replacement (3.1.12) 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
3.2.17
bursting head
tool that can crack or split the existing pipe material
3.2.18
pipe removal
on-the-line replacement (3.1.12) method, in which the existing pipe is removed by pipe eating (3.2.19) or pipe
extraction (3.2.20) and a new pipe is installed
3.2.19
pipe eating
type of pipe removal (3.2.18), where the existing pipe is progressively broken up and removed along with an
annulus of the ground immediately surrounding the existing pipe
3.2.20
pipe extraction
type of pipe removal (3.2.18), where the existing pipe 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
3.2.21
horizontal directional drilling
HDD
off-the-line trenchless replacement (3.1.14) 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 subsequently pulled/pushed into place

ISO 11295:2026(en)
3.2.22
impact moling
off-the-line trenchless replacement (3.1.14) method in which pipes are pulled in behind a pneumatic powered
soil displacement hammer
3.2.23
pipe jacking
off-the-line trenchless replacement (3.1.14) method in which pipes are pushed through the ground, and the
soil inside removed either manually, mechanically or using a slurry system
3.2.24
auger boring
type of pipe jacking (3.2.23), where the bore is excavated by a rotating cutting head attached to an auger
which continuously removes the spoil, and the pipeline is pushed independently from the auger
3.2.25
microtunnelling
type of pipe jacking (3.2.23) where pipes are pushed behind a steerable, small scale tunnelling machine,
remotely controlled from the surface
3.2.26
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
3.2.27
close-fit pipe
continuous lining pipe (3.2.2) of thermoplastic material reshaped or otherwise expanded after insertion to
achieve a close fit (3.2.26) to the existing pipeline
3.2.28
grout system
cement-based grout including any fillers, reinforcement or other additives or admixtures, in specified
proportions
3.2.29
installation manual
document that provides the information necessary to install a system or component and prepare the system
or component for operational use
[SOURCE: ISO/IEC/IEEE 24765:2017, 3.2006, modified — “set initial parameters” in the definition and other
manuals in comparison reference deleted]
3.3 Terms related to service conditions
3.3.1
internal pressure resistance
ability to withstand internal fluid pressurization
3.3.2
allowable operating pressure
PFA
maximum hydrostatic pressure that a component is capable of withstanding continuously in service.
2 5 2
Note 1 to entry: It is expressed in bars (1 bar = 0,1 MPa = 0,1 N/mm ; 1 MPa = 10 N/m ).
[SOURCE: ISO 4427-1:2019, 3.4.2, modified — bar to MPa conversion rate has been added in Note 1 to entry.]

ISO 11295:2026(en)
4 Abbreviated terms
For the purposes of this document, the abbreviated terms given in ISO 1043-1 and the following apply.
CCTV closed circuit television
CIPP cured-in-place pipe
HDD horizontal directional drilling
EP epoxy resin
GRP glass-reinforced thermosetting plastics
PA-U unplasticized polyamide
PE polyethylene
PFA allowable operating pressure
PP polypropylene
PRC polyester resin concrete
PUR polyurethane
PVC-U unplasticized poly(vinyl chloride)
RFC resin fibre composite
UP unsaturated polyester resin
VE vinyl ester resin
5 Pipeline rehabilitation process
The overall process of pipeline rehabilitation involves several sequential steps, for which this document
provides information and requirements as follows:
1) investigation of functional performance of the existing pipeline


2) condition assessment of performance against set requirements
Clause 6


3) measures to control risks / pipeline rehabilitation

4) pre-selection of suitable types of rehabilitation techniques } Clause 7
5) project specification

Clause 8

6) selection of technique/installer

7) application of rehabilitation technique

8) acceptance control Clause 9


9) documentation of the rehabilitation process
A substantial part of this document (see Clause 7) is dedicated to the classification of families of techniques
for pipeline rehabilitation, covering both renovation and trenchless replacement. Key features, including
typical product characteristics, areas of application and process related factors are described for each
technique family.
NOTE Guidance on the whole process of integrated management of drains and sewers is presented in EN 752.

ISO 11295:2026(en)
6 Investigation and condition assessment of the existing pipeline
6.1 Performance criteria
6.1.1 General
For every pipeline system, certain objectives apply depending on their intended functionality.
These are the basis for the performance requirements of a pipeline system. The pipeline system objectives
that impact on the performance requirements of the individual pipeline, shall be identified.
For drinking water distribution networks and wastewater collection networks, detailed guidance and
requirements are provided by ISO 24516-1 and ISO 24516-3, respectively. The items detailed below
specifically relate to the rehabilitation process of the pipeline systems in these networks, as well as in gas
supply networks.
Pipeline system objectives include at least the following:
— health and safety;
— environmental protection;
— sustainable operation.
Health and safety encompasses (depending on the function of the pipeline):
— provision of access to safe and good-quality drinking water;
— preventing spread of disease by safe disposal of wastewater;
— meeting the needs and expectations of users;
— minimizing occupational health and safety risks;
— maintaining pipeline system integrity.
Environmental protection includes:
— preventing pollution and minimizing generation of pollutants;
— minimizing energy consumption;
— avoiding nuisance in construction, operation and maintenance.
Sustainable operation includes:
— providing service over many years: economic, social, environmental;
— monitoring the quality of water (sampling, surveillance, maintenance);
— minimizing mains failures and leakages.
The objectives shall be transformed to performance requirements and the resulting design criteria that
ensure functionality of the pipeline system, such as: structural integrity, design working life, leaktightness,
prevention of pollution, sustainability and maintenance of flow.
Objectives can be split into the following categories:
— hydraulic requirements;
— structural requirements;
— environmental requirements;
ISO 11295:2026(en)
— operational requirements.
NOTE 1 In ISO 24512, ‘performance requirements’ are recommended to be clearly specified in objective, verifiable
‘Performance Indicators (PIs)’, allowing for a clear comparison with the targeted objectives.
NOTE 2 In EN 752, ‘performance requirements’ are for the status quo. When any predicted changes in time are
taken into account, they become ‘design criteria’.
6.1.2 Hydraulic requirements
The following hydraulic requirements shall be considered:
a) sufficient capacity, allowing for foreseeable increases in flow over the design working life of the pipeline
system;
b) ensuring operation of the pipeline system to be safe and economically efficient;
c) leaktightness in accordance with national or local te
...