ISO 21004:2006

INTERNATIONAL ISO
STANDARD 21004
First edition
2006-11-01
Plastics piping systems — Multilayer
pipes and their joints, based on
thermoplastics, for water supply
Systèmes de canalisations en plastique — Tubes multicouches et
leurs assemblages, à base de thermoplastiques, pour l'alimentation
en eau




Reference number
ISO 21004:2006(E)
©
ISO 2006

---------------------- Page: 1 ----------------------
ISO 21004:2006(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.


©  ISO 2006
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland

ii © ISO 2006 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 21004:2006(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 5
3.1 Terms and definitions related to construction . 5
3.2 Terms and definitions related to construction groups. 5
3.3 Terms and definitions related to geometry. 6
3.4 Terms and definitions related to service conditions . 7
3.5 Terms and definitions related to materials . 7
3.6 Terms and definitions related to material characteristics. 7
4 Products classification. 8
4.1 Construction group . 8
4.2 Reference product standard. 8
4.3 PN Range . 8
4.4 Design coefficient. 8
4.5 Stiffness range. 8
4.6 Specific properties. 9
5 Materials . 9
5.1 General characteristics . 9
5.2 Effect on water quality. 9
5.3 Resistance to weathering . 9
6 Long-term hydrostatic strength . 9
6.1 General. 9
6.2 Procedure I (calculation method). 10
6.3 Procedure II (testing of pipe construction method). 10
7 Geometrical characteristics. 11
7.1 General. 11
7.2 Dimensions. 11
8 Mechanical characteristics . 11
8.1 Control points for pressure characteristics.11
8.2 Structural performance . 11
9 Fittings and valves. 12
10 Fitness for purpose of the system. 12
10.1 Specific properties. 12
10.2 Jointing techniques. 13
10.3 Pressure reduction coefficients for operating temperatures. 17
11 Marking . 17
Annex A (normative) List of the reference product standards. 19
Annex B (normative) Application of design coefficient for multilayer pipes. 20
Annex C (normative) Tear test for polyethylene (PE) saddle assemblies. 21
Annex D (normative) Pressure reduction coefficients. 24
Bibliography . 25

© ISO 2006 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 21004:2006(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 21004 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 2, Plastics pipes and fittings for water supplies.

iv © ISO 2006 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 21004:2006(E)
Introduction
An overview of standards to be applied for multilayer pipes and their joints, based on thermoplastics, for water
supply, is given hereafter.
Parts Applicable standards
Materials Relevant reference product standards (see 4.2 and Clause 5 of this International
Standard)
Pipes This International Standard
Fittings Relevant reference product standards (see Clause 9 of this International Standard)
Valves Relevant reference product standards (see Clause 9 of this International Standard)
Fitness for purpose This International Standard (see Clause 10)

© ISO 2006 – All rights reserved v

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 21004:2006(E)

Plastics piping systems — Multilayer pipes and their joints,
based on thermoplastics, for water supply
1 Scope
This International Standard specifies the general requirements and the performance requirements for
multilayer pipes based on thermoplastics intended to be used for water supply outside buildings, for buried
water mains and services and for water supplies above ground.
It gives guidance for the design of piping systems consisting of multilayer pipes based on thermoplastics or,
for which at least 60 % of the wall thickness is polymeric material, and the inner layer in contact with water is
made of polymeric material.
The polymeric layers used for the stress-bearing layers are selected from polybutylene (PB), polyethylene
(PE), crosslinked polyethylene (PE-X), polypropylene (PP), chlorinated poly(vinyl chloride) (PVC-C) and
unplasticized poly(vinyl chloride) (PVC-U).
NOTE 1 For the purpose of this document, crosslinked polyethylene (PE-X) as well as adhesives are to be considered
as thermoplastic materials, and polyethylene of raised temperature resistance (PE-RT) is to be considered as
polyethylene (PE).
This document is applicable to piping systems used for the conveyance under pressure of cold water (up to
approximately 20 °C) for drinking. It is also applicable to piping systems for the conveyance of water (up to
and including 40 °C) for general purposes.
It applies where special functional requirements are needed.
NOTE 2 As an example, the different pipe layers can provide information on colour, barrier and mechanical properties,
according to the intended application.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 161-1, Thermoplastics pipes for the conveyance of fluids — Nominal outside diameters and nominal
pressures ⎯ Part 1: Metric series
ISO 161-2, Thermoplastics pipes for the conveyance of fluids — Nominal outside diameters and nominal
pressures ⎯ Part 2: Inch-based series
ISO 472, Plastics — Vocabulary
ISO 527-1, Plastics — Determination of tensile properties — Part 1: General principles
ISO 527-1:1993/Cor.1:1994, Plastics — Determination of tensile properties — Part 1: General principles
ISO 527-2, Plastics — Determination of tensile properties — Part 2: Test conditions for moulding and extrusion
plastics
© ISO 2006 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO 21004:2006(E)
ISO 1043-1, Plastics — Symbols and abbreviated terms — Part 1: Basic polymers and their special
characteristics
ISO 1167-1, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of
the resistance to internal pressure — Part 1: General method
ISO 1167-2, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of
the resistance to internal pressure — Part 2: Preparation of pipe test pieces
ISO 3126, Plastics piping systems — Plastics components — Determination of dimensions
ISO 3213, Polypropylene (PP) pipes — Effect of time and temperature on expected strength
ISO 3459, Polyethylene (PE) pressure pipes — Joints assembled with mechanical fittings — Internal under-
pressure test method and requirement
ISO 3501, Assembled joints between fittings and polyethylene (PE) pressure pipes — Test of resistance to
pull out
ISO 3503, Assembled joints between fittings and polyethylene (PE) pressure pipes — Test of leakproofness
under internal pressure when subjected to bending
ISO 4422-1, Pipes and fittings made of unplasticized poly(vinyl chloride) (PVC-U) for water supply ⎯
Specifications ⎯ Part 1: General
ISO 4422-2, Pipes and fittings made of unplasticized poly(vinyl chloride) (PVC-U) for water supply —
Specifications — Part 2: Pipes (with or without integral sockets)
ISO 4422-3, Pipes and fittings made of unplasticized poly(vinyl chloride) (PVC-U) for water supply ⎯
Specifications ⎯ Part 3: Fittings and joints
ISO 4422-4, Pipes and fittings made of unplasticized poly(vinyl chloride) (PVC-U) for water supply ⎯
Specifications ⎯ Part 4: Valves and ancillary equipment
ISO 4422-5, Pipes and fittings made of unplasticized poly(vinyl chloride) (PVC-U) for water supply ⎯
Specifications ⎯ Part 5: Fitness for purpose of the system
1)
ISO 4427-1 , Plastics piping systems ⎯ Polyethylene (PE) pipes and fittings for water supply ⎯ Part 1:
General
1)
ISO 4427-2 , Plastics piping systems ⎯ Polyethylene (PE) pipes and fittings for water supply ⎯ Part 2:
Pipes
1)
ISO 4427-3 , Plastics piping systems ⎯ Polyethylene (PE) pipes and fittings for water supply ⎯ Part 3:
Fittings
1)
ISO 4427-5 , Plastics piping systems ⎯ Polyethylene (PE) pipes and fittings for water supply ⎯ Part 5:
Fitness for purpose of the system
ISO 6259-1, Thermoplastics pipes — Determination of tensile properties — Part 1: General test method
ISO 6259-2, Thermoplastics pipes — Determination of tensile properties — Part 2: Pipes made of unplasticized
poly(vinyl chloride) (PVC-U), chlorinated poly(vinyl chloride) (PVC-C) and high-impact poly(vinyl chloride)
(PVC-HI)

1) To be published.
2 © ISO 2006 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 21004:2006(E)
ISO 6259-3, Thermoplastics pipes — Determination of tensile properties — Part 3: Polyolefin pipes
ISO 9080, Plastics piping and ducting systems — Determination of long-term hydrostatic strength of
thermoplastics material in pipe form by extrapolation
ISO 9969, Thermoplastics pipes ⎯ Determination of ring stiffness
ISO 10146, Crosslinked polyethylene (PE-X) pipes ⎯ Effect of time and temperature on the expected strength
ISO 11413:1996, Plastics pipes and fittings ⎯ Preparation of test piece assemblies between a polyethylene
(PE) pipe and an electrofusion fitting
ISO 11414:1996, Plastics pipes and fittings ⎯ Preparation of polyethylene (PE) pipe/pipe or pipe/fitting test
piece assemblies by butt fusion
ISO 12230, Polybutene (PB) pipes ⎯ Effect of time and temperature on the expected strength
ISO 13761, Plastics pipes and fittings — Pressure reduction factors for polyethylene pipeline systems for use
at temperatures above 20 degrees C
ISO 13783, Plastics piping systems ⎯ Unplasticized poly(vinyl chloride) (PVC-U) end-load-bearing double-
socket joints ⎯ Test method for leaktightness and strength while subjected to bending and internal pressure
ISO 13844, Plastics piping systems ⎯ Elastomeric-sealing-ring-type socket joints of unplasticized poly(vinyl
chloride) (PVC-U) for use with PVC-U pipes ⎯ Test method for leaktightness under negative pressure
ISO 13845, Plastics piping systems ⎯ Elastomeric-sealing-ring-type socket joints for use with unplasticized
poly(vinyl chloride) (PVC-U) pipes ⎯ Test method for leaktightness under internal pressure and with angular
deflection
ISO 13846, Plastics piping systems ⎯ End-load-bearing and non-end-load-bearing assemblies and joints for
thermoplastics pressure piping ⎯ Test method for long-term leaktightness under internal water pressure
ISO 13953, Polyethylene (PE) pipes and fittings ⎯ Determination of the tensile strength and failure mode of
test pieces from a butt-fused joint
ISO 13954, Plastics pipes and fittings ⎯ Peel decohesion test for polyethylene (PE) electrofusion assemblies
of nominal outside diameter greater than or equal to 90 mm
ISO 13955, Plastics pipes and fittings ⎯ Crushing decohesion test for polyethylene (PE) electrofusion
assemblies
ISO 13968, Plastics piping and ducting systems ⎯ Thermoplastics pipes ⎯ Determination of ring flexibility
ISO 15874-1, Plastics piping systems for hot and cold water installations ⎯ Polypropylene (PP) ⎯ Part 1:
General
ISO 15874-2, Plastics piping systems for hot and cold water installations ⎯ Polypropylene (PP) ⎯ Part 2:
Pipes
ISO 15874-3, Plastics piping systems for hot and cold water installations ⎯ Polypropylene (PP) ⎯ Part 3:
Fittings
ISO 15874-5, Plastics piping systems for hot and cold water installations ⎯ Polypropylene (PP) ⎯ Part 5:
Fitness for purpose of the system
ISO 15875-1, Plastics piping systems for hot and cold water installations ⎯ Crosslinked polyethylene (PE-X) ⎯
Part 1: General
© ISO 2006 – All rights reserved 3

---------------------- Page: 8 ----------------------
ISO 21004:2006(E)
ISO 15875-2, Plastics piping systems for hot and cold water installations ⎯ Crosslinked polyethylene (PE-X) ⎯
Part 2: Pipes
ISO 15875-3, Plastics piping systems for hot and cold water installations ⎯ Crosslinked polyethylene (PE-X) ⎯
Part 3: Fittings
ISO 15875-5, Plastics piping systems for hot and cold water installations ⎯ Crosslinked polyethylene (PE-X) ⎯
Part 5: Fitness for purpose of the system
ISO 15876-1, Plastics piping systems for hot and cold water installations ⎯ Polybutylene (PB) ⎯ Part 1:
General
ISO 15876-2, Plastics piping systems for hot and cold water installations ⎯ Polybutylene (PB) ⎯ Part 2:
Pipes
ISO 15876-3, Plastics piping systems for hot and cold water installations ⎯ Polybutylene (PB) ⎯ Part 3:
Fittings
ISO 15876-5, Plastics piping systems for hot and cold water installations ⎯ Polybutylene (PB) ⎯ Part 5:
Fitness for purpose of the system
ISO 15877-1, Plastics piping systems for hot and cold water installations ⎯ Chlorinated poly(vinyl chloride)
(PVC-C) ⎯ Part 1: General
ISO 15877-2, Plastics piping systems for hot and cold water installations ⎯ Chlorinated poly(vinyl chloride)
(PVC-C) ⎯ Part 2: Pipes
ISO 15877-3, Plastics piping systems for hot and cold water installations ⎯ Chlorinated poly(vinyl chloride)
(PVC-C) ⎯ Part 3: Fittings
ISO 15877-5, Plastics piping systems for hot and cold water installations ⎯ Chlorinated poly(vinyl chloride)
(PVC-C) ⎯ Part 5: Fitness for purpose of the system
ISO 16871, Plastics piping and ducting systems ⎯ Plastics pipes and fittings ⎯ Method for exposure to direct
(natural) weathering
ISO 17454, Plastics piping systems — Multilayer pipes — Test method for the adhesion of the different layers
using a pulling rig
1)
ISO 17456:— , Plastics piping systems — Multilayer pipes — Determination of long-term strength
1)
ISO 22391-1 , Plastics piping systems for hot and cold water installations — Polyethylene of raised
temperature resistance (PE-RT) — Part 1: General
1)
ISO 22391-2 , Plastics piping systems for hot and cold water installations — Polyethylene of raised
temperature resistance (PE-RT) — Part 2: Pipes
1)
ISO 22391-3 , Plastics piping systems for hot and cold water installations — Polyethylene of raised
temperature resistance (PE-RT) — Part 3: Fittings
1)
ISO 22391-5 , Plastics piping systems for hot and cold water installations — Polyethylene of raised
temperature resistance (PE-RT) — Part 5: Fitness for purpose of the system
1)
ISO 24033 , Pipes made of raised-temperature-resistance polyethylene (PE-RT) — Effect of time and
temperature on the expected strength
4 © ISO 2006 – All rights reserved

---------------------- Page: 9 ----------------------
ISO 21004:2006(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472 and ISO 1043-1 and the
following apply.
3.1 Terms and definitions related to construction
3.1.1
multilayer pipe
pipe comprising more than one layer in which at least 60 % of the wall thickness is a polymeric material
3.1.2
multilayer M pipe
multilayer pipe comprising layers of polymers and one or more metallic layers
NOTE The wall thickness of the pipe consists of at least 60 % of polymer layers.
3.1.3
multilayer P pipe
multilayer pipe comprising two or more polymeric layers
3.1.4
inner layer
layer in contact with the conveyed fluid
3.1.5
outer layer
layer exposed to the outer environment
3.1.6
embedded layer
layer between the outer and inner layer
3.1.7
application layer
layer which provides a specific property linked to the conditions of use of the pipe
3.2 Terms and definitions related to construction groups
3.2.1
reference product standard
International Standard or Draft International Standard prepared by Technical Committee ISO/TC 138,
Subcommittee SC 2, applicable for non-multilayer pipes, to which this document can refer for clauses related
to the materials, components (e.g. fittings), and fitness for purpose of the system
3.2.2
construction group A
group comprising multilayer pipes in which all the layers considered to be stress-bearing are made of
polymeric materials selected from the list of reference product standards
3.2.3
construction group B
group comprising multilayer pipes in which all the layers considered to be stress-bearing are made of
polymeric materials selected from the list of reference product standards and including a stress-bearing
metallic layer
© ISO 2006 – All rights reserved 5

---------------------- Page: 10 ----------------------
ISO 21004:2006(E)
3.2.4
similar construction type
〈multilayer M pipes〉 construction type which is the same for more than one pipe diameter under the following
conditions:
⎯ the same process technology is used (e.g. welding process for the aluminium layers, type of welding,
etc.);
⎯ materials having the same characteristics are used for each stress-bearing layer; i.e. material type and
specifications;
⎯ the layers are assembled in the same sequence for different diameters;
⎯ for all diameters, the SDR of the metal layer is the same ± 10 %.
m
NOTE If for a certain diameter range, the same metal layer thickness is used, the SDR value of the metal layer of all
m
smaller diameters of this diameter range can be adapted up to the SDR of the metal layer for the biggest diameter of the
m
diameter range (e.g. a diameter range from 12 mm up to 20 mm with a 0,2 mm metal layer).
3.3 Terms and definitions related to geometry
3.3.1
nominal size
DN
numerical designation of the size of a component, other than a component designated by a thread size, which
is a convenient round number, approximately equal to the manufacturing dimension
NOTE The nominal size is expressed in millimetres.
3.3.2
nominal size
DN/OD
nominal size, related to the outside diameter
3.3.3
nominal outside diameter
d
n
specified outside diameter assigned to a nominal size DN/OD
NOTE The nominal outside diameter is expressed in millimetres.
3.3.4
outside diameter at any point
d
e
outside diameter measured through the cross-section at any point on a pipe, or the spigot end of a fitting
NOTE The outside diameter at any point is rounded up to the nearest 0,1 mm.
3.3.5
mean outside diameter
d
em
measured length of the outer circumference of a pipe, or the spigot end of a fitting, divided by π (≈ 3,142)
NOTE The mean outside diameter is rounded up to the nearest 0,1 mm.
3.3.6
out-of-roundness
difference between the measured maximum outside diameter and the measured minimum outside diameter in
the same cross-sectional plane of a pipe, or the spigot end of a fitting
6 © ISO 2006 – All rights reserved

---------------------- Page: 11 ----------------------
ISO 21004:2006(E)
3.3.7
metal layer standard dimension ratio
SDR
m
nominal outside diameter (DN/OD) divided by the nominal wall thickness of the metal layer e
n,m
3.4 Terms and definitions related to service conditions
3.4.1
nominal pressure
PN
numerical designation used for reference purposes and related to the mechanical characteristics of the
components of a piping system
NOTE For plastics piping systems conveying water, nominal pressure corresponds to the maximum continuous
2)
operating pressure in bars which can be sustained with water at 20 °C for 50 years, based on the minimum overall
service (design) coefficient.
3.5 Terms and definitions related to materials
3.5.1
virgin material
material in a form such as granules or powder that has not been subjected to use or processing other than
that required for its manufacture and to which no reprocessable or recyclable material has been added
3.5.2
own reprocessable material
material prepared from clean unused rejected pipes or fittings, produced in a manufacturer's plant by a
process such as moulding or extrusion, which will be reprocessed in the same plant and for which the
complete formulation or material specification is known
3.5.3
external reprocessable material
material from unused rejected pipes or trimmings therefrom, that will be reprocessed and that were originally
processed by another manufacturer, or material from the production of unused products other than pipes and
fittings, regardless of where they are manufactured
3.6 Terms and definitions related to material characteristics
3.6.1
long-term hydrostatic strength
σ
LTHS
quantity with the dimensions of stress, which represents the predicted mean strength at a temperature T and
time t
NOTE The long-term hydrostatic strength is expressed in megapascals.
3.6.2
lower confidence limit of the predicted hydrostatic strength
σ
LPL
quantity with the dimensions of stress, which represents the 97,5 % lower confidence limit of the predicted
hydrostatic strength at a temperature T and time t
NOTE 1 It is given by
σ = σ
LPL (T, t, 0,975)
NOTE 2 The lower confidence limit of the predicted hydrostatic strength is expressed in megapascals.

5 2
2) 1 bar = 0,1 MPa = 10 N/mm .
© ISO 2006 – All rights reserved 7

---------------------- Page: 12 ----------------------
ISO 21004:2006(E)
3.6.3
minimum required strength
MRS
value of σ at 20 °C and 50 years
LPL
NOTE 1 The value is rounded down to the next lower value in the R 10 series when σ is less than 10 MPa, or to the
LPL
next lower value in the R 20 series when σ is greater than or equal to 10 MPa.
LPL
[1] [2]
NOTE 2 R10 and R20 series are the Renard number series according to ISO 3:1973 and ISO 497:1973 .
3.6.4
minimum required pressure
MRP
value of the estimated long-term hydrostatic pressure strength of a pipe at a temperature of 20 °C and a time
50 years
NOTE The value is rounded down to the next lower value of the R10 series.
4 Products classification
4.1 Construction group
The multilayer pipes can include polymeric or metallic layers which may have several purposes including the
ability to withstand the pressure.
For the purpose of this document, multilayer pipes are classified in two construction groups as defined in 3.2.
For these definitions, adhesives are not considered as stress-bearing layers.
The pipe manufacturer shall declare the construction group of the multilayer pipe.
4.2 Reference product standard
The pipe manufacturer shall declare the reference product standard applicable to his product, as listed in
Annex A.
4.3 PN Range
PN values shall be selected from the following PN range: PN 6; PN 6,3; PN 8; PN 10; PN 12,5; PN 16; PN 20;
PN 25.
Above PN 25, other PN values may be used following the Renard R 10 series.
National regulations should be taken into account in the selection of the PN value.
4.4
...