ISO/FDIS 11295

ISO/TC 138/SC 8
Secretariat: JISC
ISO/TC 138/SC 8/WG 1
Secretariat: BSI
Date: 2025-08-0310-21
Plastics piping systems used for 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

FDIS stage
This document is not an ISO International Standard. It is distributed for review and comment. It is subject to change
without notice and may not be referred to as an International Standard.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which
they are aware and to provide supporting documentation.

ISO/DIS FDIS 11295:20242025(en)
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ii © ISO 2024 – All rights reserved
ii
Contents
Foreword . v
Introduction . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviated terms . 7
5 Pipeline rehabilitation process . 8
6 Investigation and condition assessment of the existing pipeline . 9
7 Classification and characteristics of rehabilitation techniques. 16
8 Selection of rehabilitation techniques . 72
9 Implementation of rehabilitation techniques . 81
Bibliography . 87

3.1 General terms . 2
3.2 Terms related to techniques . 4
3.3 Terms related to services conditions . 7
6.1 Performance criteria . 8
6.1.1 General . 8
6.1.2 Hydraulic requirements . 10
6.1.3 Structural requirements . 10
6.1.4 Environmental requirements . 10
6.1.5 Operational requirements . 11
6.2 Investigation of performance . 11
6.2.1 General . 11
6.2.2 Hydraulic investigation . 12
6.2.3 Structural investigation . 13
6.2.4 Environmental investigation . 14
6.2.5 Operational investigation . 14
6.3 Condition assessment . 14
6.4 Risk analysis . 15
6.5 Control measures . 15
7.1 Overview . 15
7.2 Classification of renovation techniques . 17
7.2.1 General . 17
7.2.2 Lining with continuous pipes . 17
7.2.3 Lining with close-fit pipes . 20
7.2.4 Lining with cured-in-place pipes . 23
7.2.5 Lining with discrete pipes . 27
7.2.6 Lining with adhesive-backed hoses . 30
7.2.7 Lining with spirally-wound pipes . 32
7.2.8 Lining with pipe segments . 35
7.2.9 Lining with a rigidly anchored plastics inner layer . 37
7.2.10 Lining with sprayed polymeric materials . 39
7.2.11 Lining with inserted hoses . 40
7.3 Classification of trenchless replacement techniques . 42
iii
ISO/DIS FDIS 11295:20242025(en)
7.3.1 General . 42
7.3.2 Pipe bursting . 42
7.3.3 Pipe removal . 45
7.3.4 Horizontal directional drilling (HDD) . 48
7.3.5 Impact moling . 51
7.3.6 Pipe jacking . 53
8.1 General . 56
8.2 Pipeline system layout . 57
8.3 Hydraulic performance . 57
8.4 Structural performance . 58
8.4.1 General . 58
8.4.2 Non-pressure pipes . 58
8.4.3 Pressure pipes . 60
8.5 Environmental impact . 63
8.6 Construction constraints . 63
8.7 Project specification. 64
9.1 Preconstruction activities . 65
9.2 Assessment of conformity of products . 66
9.3 Inspection, storage and handling of the materials on site . 66
9.4 Application of rehabilitation technique . 67
9.4.1 Preparatory work . 67
9.4.2 Construction . 67
9.5 Acceptance control . 67
9.5.1 General . 67
9.5.2 Leak tightness testing . 68
9.5.3 Sampling . 69
9.6 Completion of the work . 69
9.6.1 Finishing off the rehabilitation work . 69
9.6.2 Lateral reinstatement . 69
9.7 Documentation of the process . 70
iv © ISO 2024 – All rights reserved
iv
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
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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.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 3.3.12);
— 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).
— twelve existing definitions have been modified (Error! Reference source not found., Error! Reference
source not found., Error! Reference source not found., Error! Reference source not found., Error!
Reference source not found., Error! Reference source not found., Error! Reference source not
found., Error! Reference source not found., Error! Reference source not found., Error! Reference
source not found., Error! Reference source not found. and Error! Reference source not found.);
v
ISO/DIS FDIS 11295:20242025(en)
— fourteen new terms have been defined (Error! Reference source not found., Error! Reference source
not found., Error! Reference source not found., Error! Reference source not found., Error!
Reference source not found., Error! Reference source not found., Error! Reference source not
found., Error! Reference source not found., Error! Reference source not found., Error! Reference
source not found., Error! Reference source not found., Error! Reference source not found., Error!
Reference source not found. and Error! Reference source not found.).
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.htmlwww.iso.org/members.html.
vi © ISO 2024 – All rights reserved
vi
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) a) investigation and assessment of the deficiencies of current performance of the existing
pipeline;
b) b) determination of viable options, based on performance criteria and process-related factors;
c) c) specification of the selected type of technique and the required pipe material;
d) d) the installation;
e) 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.
vii
DRAFT International Standard ISO/FDIS 11295:2025(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) a) investigation and condition assessment of the existing pipeline;
b) b) pipeline rehabilitation planning.
— — operational activities:
c) c) project specification;
d) d) applications of techniques;
e) 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, and 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 pressure 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
ISO/DIS FDIS 11295:20242025(en)
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/obphttps://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
3.1 General terms
3.1.1 3.1.1
assessment
process, or result of this process, comparing a specified subject matter to relevant references
3.1.2 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)(Error! Reference
source not found.) and maintenance (Error! Reference source not found.) but without renovation (Error!
Reference source not found.) or replacement (Error! Reference source not found.) being necessary
3.1.3 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 3.1.4
pipeline system
interconnecting pipe network for the conveyance of fluids
3.1.5 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),(Error! Reference source not found.), gullies and other network
components
[SOURCE: ISO 6707-1:2020, 3.3.4.38, modified — details of connections have been added]
3.1.6 3.1.6
sewer
pipeline which conveys waste water, including its connections to lateral pipes, manholes (3.1.7),(Error!
Reference source not found.), manhole chambers (3.1.8)(Error! Reference source not found.) and other
network components
[SOURCE: ISO 6707-1:2020, 3.3.4.41, modified — details of connections have been added ]
2 © ISO 2024 – All rights reserved
3.1.7 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 3.1.8
manhole chamber
chamber constructed on a drain (3.1.5),(Error! Reference source not found.), sewer (3.1.6),(Error!
Reference source not found.), or pipeline, with a removable cover permitting entry of a person
[SOURCE: ISO 6707-1:2020, 3.3.4.20]
3.1.9 3.1.9
rehabilitation
measures for restoring or upgrading the performance of existing pipeline systems (3.1.4),(Error! Reference
source not found.), including renovation (3.1.10),(Error! Reference source not found.), repair
(3.1.11)(Error! Reference source not found.) and replacement (3.1.12)(Error! Reference source not
found.)
3.1.10 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 3.1.11
repair
rectification of local damage
3.1.12 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)(Error! Reference source not found.) incorporates that of the old
3.1.13 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 3.1.14
trenchless replacement
replacement (3.1.12)replacement (Error! Reference source not found.) without opening trenches other than
small excavations to provide access for the particular technique and for service and lateral connections
3.1.15 3.1.15
maintenance
routine work undertaken to ensure the existing performance of an asset
3.1.16 3.1.16
independent pressure pipe liner
liner (3.2.3)liner (Error! Reference source not found.) 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)(Error! Reference source not found.) or semi-
structural renovation (3.1.19)(Error! Reference source not found.) with respect to external loading
ISO/DIS FDIS 11295:20242025(en)
3.1.17 3.1.17
interactive pressure pipe liner
liner (3.2.3)liner (Error! Reference source not found.) 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 3.1.18
fully-structural renovation
use of an independent pressure pipe liner (3.1.16)(Error! Reference source not found.) or non-pressure liner
which is capable of resisting all external loads irrespective of the condition of the existing pipeline
3.1.19 3.1.19
semi-structural renovation
use of an interactive pressure pipe liner (3.1.17)(Error! Reference source not found.) which is capable of long-
term hole and gap spanning at operational pressure
3.1.20 3.1.20
non-structural renovation
use of an interactive pressure pipe liner (3.1.17)(Error! Reference source not found.) which is not capable of
long-term hole and gap spanning at operational pressure
3.1.21 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
3.1.22 3.1.22
CCTV
closed-circuit television
system comprised of cameras, recorders, interconnections and displays that are used to inspect pipelines
3.1.23 3.1.23
system test pressure
pressure applied to the installed pipeline system (3.1.4)(Error! Reference source not found.) in order to
ensure its integrity and leaktightness
3.1.24 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 3.1.25
simulated installation
installation of all or part of a lining system (3.2.4)(Error! Reference source not found.) into a simulated host
pipeline (3.1.24),(Error! Reference source not found.), 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 3.2.1
technique family
grouping of rehabilitation (3.1.9)(Error! Reference source not found.) techniques which are considered to
have common characteristics for standardization purposes
4 © ISO 2024 – All rights reserved
3.2.2 3.2.2
lining pipe
pipe inserted for renovation (3.1.10)(Error! Reference source not found.) purposes prior to any site
processing
3.2.3 3.2.3
liner
lining pipe (3.2.2)(Error! Reference source not found.) after installation
3.2.4 3.2.4
lining system
lining pipe (3.2.2)(Error! Reference source not found.) and all relevant fittings for insertion into an existing
pipeline for the purposes of renovation (3.1.10)(Error! Reference source not found.)
3.2.5 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)(Error!
Reference source not found.) remains unchanged
3.2.6 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)(Error! Reference source not found.) to the existing pipe
3.2.7 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 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 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
3.2.10 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 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 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 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
ISO/DIS FDIS 11295:20242025(en)
3.2.14 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 3.2.15
replacement pipe
new pipe installed for rehabilitation purposes
3.2.16 3.2.16
pipe bursting
on-the-line replacement (3.1.12)(Error! Reference source not found.) 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 3.2.17
bursting head
tool that can crack or split the existing pipe material
3.2.18 3.2.18
pipe removal
on-the-line replacement (3.1.12)(Error! Reference source not found.) method, in which the existing pipe is
removed by pipe eating (3.2.19)(Error! Reference source not found.) or pipe extraction (3.2.20)(Error!
Reference source not found.) and a new pipe is installed
3.2.19 3.2.19
pipe eating
type of pipe removal (3.2.18),(Error! Reference source not found.), 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 3.2.20
pipe extraction
type of pipe removal (3.2.18),(Error! Reference source not found.), 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 3.2.21
horizontal directional drilling
HDD
off-the-line trenchless replacement (3.1.14)(Error! Reference source not found.) 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
3.2.22 3.2.22
impact moling
off-the-line trenchless replacement (3.1.14)(Error! Reference source not found.) method in which pipes are
pulled in behind a pneumatic powered soil displacement hammer
6 © ISO 2024 – All rights reserved
3.2.23 3.2.23
pipe jacking
off-the-line trenchless replacement (3.1.14)(Error! Reference source not found.) 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 3.2.24
auger boring
type of pipe jacking (3.2.23),(Error! Reference source not found.), 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 3.2.25
microtunnelling
type of pipe jacking (3.2.23)(Error! Reference source not found.) where pipes are pushed behind a steerable,
small scale tunnelling machine, remotely controlled from the surface
3.2.26 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 3.2.27
close-fit pipe
continuous lining pipe (3.2.2)(Error! Reference source not found.) of thermoplastic material reshaped or
otherwise expanded after insertion to achieve a close fit (3.2.26)(Error! Reference source not found.) to the
existing pipeline
3.2.28 3.2.28
grout system
cement-based grout including any fillers, reinforcement or other additives or admixtures, in specified
proportions
3.2.29 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 services conditions
3.3.1 3.3.1
internal pressure resistance
ability to withstand internal fluid pressurization
3.3.2 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/DIS FDIS 11295:20242025(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
DN nominal diameter
DN nominal diameter
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



condition assessment of performance against set requirements

)
Clause 66

}
measures to control risks / pipeline rehabilitation
)
 } Clause 77
pre-selection of suitable types of rehabilitation techniques
)
project specification 
)

Clause 88

selection of technique / /installer }

)
Clause 99
application of rehabilitation technique
)
8 © ISO 2024 – All rights reserved

8 
acceptance control

)
}
 9.7
documentation of the rehabilitation process
)
A substantial part of this document (see Clause 7)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.
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 user’s needs and expectations;
— — minimizing occupational health and safety risks;
— — maintaining pipeline system integrity.
Environmental protection includes:
— — preventing pollution and minimizing generation of pollutants;
— — minimizing energy consumption;
ISO/DIS FDIS 11295:20242025(en)
— — 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, leak
tightnessleaktightness, prevention of pollution, sustainability and maintenance of flow.
Objectives can be split into the following categories:
— — hydraulic requirements;
— — structural requirements;
— — environmental requirements;
— — 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) a) sufficient capacity, allowing for foreseeable increases in flow over the design working life of
the pipeline system;
b) b) ensuring operation of the pipeline system to be safe and economically efficient;
c) c) leak tightnessleaktightness in accordance with national or local testing requirements;
d) d) in the case of water supply pipelines, national or local regulations can additionally require:
— — safeguarding of water quality;
— — sufficient pressure, flow rate and continuity of supply;
— — prevention of back flow (via valves and wash outs);
— — minimization of stagnation to avoid possible deterioration of water quality;
— — requirements for firefighting (hydrants) to follow requirements of national legislation;
10 © ISO 2024 – All rights reserved
— — prevention of contamination at pumping stations.
e) e) in the case of non-pressure drains and sewers,
— — national or local regulations or the relevant authority can specify requirements for limitation
of surcharge or flooding.
6.1.3 Structural requirements
The following shall apply:
a) a) structural integrity over the design working life of the pipeline system;
The pipeline system shall be able to withstand the loads without defects which can:
— — lead to risk of loss of structural integrity;
— — impair the function of the pipeline system.
6.1.4 Environmental requirements
The following shall apply:
a) a) protection of groundwater;
b) b) sustainable use of products and potential re-use through recycling;
c) c) minimization of the use of energy over the design working life of the pipeline system;
d) d) prevention of odours and toxic, explosive and corrosive gases.
6.1.5 Operational requirements
The following shall apply:
a) a) trouble-free operation of the pipeline system, without interruptions of service;
b) b) minimization of the risk of failures: collapses (non-pressure pipelines) or bursts (pressure
pipelines);
c) c) maintenance to be carried out safely and without risks to the health of personnel;
d) d) adequate access and working space;
e) e) prevention of noise and vibration;
f) f) not endangering adjacent structures and utility services.
6.2 Investigation of performance
6.2.1 General
Prior to the actual investigation, the following basic information about the existing pipeline shall be collected:
a) a) location;
ISO/DIS FDIS 11295:20242025(en)
b) b) pipe material;
c) c) actual internal diameter or other non-circular cross-section dimensions;
d) d) wall thickness (especially in the case of pressure pipelines where interactive lining is
considered);
e) e) fluid transported;
f) f) accessibility and section lengths between access points;
g) g) frequency and location of any lateral connections, branches and/or valves;
h) h) depth of cover;
i) i) height of ground water table (both mean long-term and peak short-term);
j) j) flow;
k) k) failure and repair records;
l) l) historical operating pressure regimes;
m) m) traffic or other surface loads;
n) n) proximity of adjacent buried services and structures.
NOTE 1 Some of this information can be ascertained from records and plans.
If available, the following additional information shall be acquired additionally:
— — year of installation;
— — pipe class (e.g. crushing strength, stiffness or pressure class);
— — joint type;
— — bedding an
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