ISO 4633:2023

INTERNATIONAL ISO
STANDARD 4633
Fifth edition
2023-08
Rubber seals — Joint rings for water
supply, drainage and sewerage
pipelines — Specification for
materials
Joints étanches en caoutchouc — Garnitures de joints de canalisations
d'adduction et d'évacuation d'eau (égouts inclus) — Spécification des
matériaux
Reference number
ISO 4633:2023(E)
© ISO 2023

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ISO 4633:2023(E)
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© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO 4633:2023(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Classification . 2
5 Requirements . 2
5.1 General . 2
5.2 Effect on water quality . 2
5.3 Microbiological deterioration . 3
5.4 Dimensional tolerances . 3
5.5 Imperfections and defects . 3
5.6 Hardness . 3
5.7 Tensile strength and elongation at break . 3
5.8 Compression set in air. 3
5.8.1 General . 3
5.8.2 Compression set at 23 °C and 70 °C . 4
5.8.3 Low-temperature compression set at –10 °C . 4
5.9 Accelerated ageing in air . 4
5.10 Stress relaxation in compression . 4
5.11 Volume change in water . 4
5.12 Ozone resistance . 5
5.13 Splices of prevulcanized profile ends . 5
5.13.1 Spliced joints . 5
5.13.2 Strength of spliced joints . 5
5.14 Summary of physical property requirements . 5
6 Optional requirements . 6
6.1 Low temperature performance at –25 °C, (type L) . 6
6.2 Volume change in oil, (type O) . 6
6.3 Lifetime estimation, (type LT) . 6
6.3.1 General . 6
6.3.2 Method 1 by stress relaxation . 7
6.3.3 Method 2 by compression set. 7
6.4 Summary of optional property requirements . 7
7 Test pieces and test temperature . .8
7.1 Preparation of test pieces . 8
7.2 Test temperature . 8
8 Quality assurance . 8
9 Storage . 8
10 Designation . 8
11 Marking and labelling . 9
Annex A (normative) Determination of splice strength .10
Annex B (informative) Quality assurance .11
Annex C (informative) Guidance on storage of seals .12
Annex D (informative) Remarks regarding the lifetime estimation in 6.3 .13
Bibliography .14
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ISO 4633:2023(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 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
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database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
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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 45, Rubber and rubber products,
Subcommittee SC 4, Products (other than hoses).
This fifth edition cancels and replaces the fourth edition (ISO 4633:2015), which has been technically
revised.
The main changes are as follows:
— estimation of lifetime and lifetime classes have been added as optional requirement;
— structural changes in the document.
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.
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INTERNATIONAL STANDARD ISO 4633:2023(E)
Rubber seals — Joint rings for water supply, drainage and
sewerage pipelines — Specification for materials
WARNING — Persons using this document should be familiar with normal laboratory practice.
This document does not purport to address all of the safety problems, if any, associated with its
use. It is the responsibility of the user to establish appropriate safety and health practices.
1 Scope
This document specifies requirements for materials used in vulcanized rubber seals for the following:
a) cold drinking-water supplies (up to 50 °C);
b) drainage, sewerage, and rainwater systems (continuous flow up to 45 °C and intermittent flow up
to 95 °C).
The different designations of seals specified are defined according to their type, application, and
requirements (see Table 5).
General requirements for finished joint seals are also given; any additional requirements called for by
the particular application are specified in the relevant product standards, taking into account that the
performance of pipe joints is a function of the seal material properties, seal geometry, and pipe joint
design. This document is intended to be used, where appropriate, with product standards which specify
performance requirements for joints.
This document is applicable to joint seals for all pipeline materials, including iron, steel, clay, fibre
cement, concrete, reinforced concrete, plastics, and glass-reinforced plastics.
It is applicable to elastomeric components of composite or non-composite seals. In the case of composite
seals for materials of hardness ranges from 76 IRHD-M to 95 IRHD-M, the requirements for elongation
at break, compression set, and stress relaxation apply only when the material is participating in the
sealing function or in the long-term stability of the seal.
Joint seals made with an enclosed void as part of their design are included in the scope of this document.
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 37, Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties
ISO 48-2, Rubber, vulcanized or thermoplastic — Determination of hardness — Part 2: Hardness between
10 IRHD and 100 IRHD
ISO 188:2023, Rubber, vulcanized or thermoplastic — Accelerated ageing and heat resistance tests
ISO 815-1:2019, Rubber, vulcanized or thermoplastic — Determination of compression set — Part 1: At
ambient or elevated temperatures
ISO 815-2, Rubber, vulcanized or thermoplastic — Determination of compression set — Part 2: At low
temperatures
ISO 1431-1, Rubber, vulcanized or thermoplastic — Resistance to ozone cracking — Part 1: Static and
dynamic strain testing
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ISO 4633:2023(E)
ISO 1817, Rubber, vulcanized or thermoplastic — Determination of the effect of liquids
ISO 3302-1, Rubber — Tolerances for products — Part 1: Dimensional tolerances
ISO 3384-1:2019, Rubber, vulcanized or thermoplastic — Determination of stress relaxation in compression
— Part 1: Testing at constant temperature
ISO 3387, Rubber — Determination of crystallization effects by hardness measurements
ISO 9691:1992, Rubber — Recommendations for the workmanship of pipe joint rings — Description and
classification of imperfections
ISO 11346, Rubber, vulcanized or thermoplastic — Estimation of life-time and maximum temperature of
use
ISO 23529, Rubber — General procedures for preparing and conditioning test pieces for physical test
methods
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Classification
Six classes of material for pipe joint seals are specified in Table 2 and Table 4 and three classes of
material in Table 5. A nominal hardness shall be specified within the ranges in Table 1.
Table 1 — Hardness classification
a
Hardness class 40 50 60 70 80 90
Range of hardness, 36 to 45 46 to 55 56 to 65 66 to 75 76 to 85 86 to 95
IRHD-M
a
The hardness class follows directly from the nominal hardness, which is the typical hardness of a specific compound.
The hardness class is not a requirement. If a compound has a nominal hardness of 47 IRHD-M, the hardness class is 50. A
tolerance of ±5 (see Table 2) means that the hardness can be between 42 IRHD-M and 52 IRHD-M.
5 Requirements
5.1 General
The materials shall be free of any substances which can have a deleterious effect on the fluid being
conveyed, the life of the sealing ring, the pipe, or the fitting. Elastomeric components of composite seals
not exposed to the contents of the pipeline are not required to meet the requirements of 5.4 to 5.14.
5.2 Effect on water quality
For cold-water applications, the materials shall not impair the quality of the water under the conditions
of use. The materials shall comply with the national requirements in the country of use.
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ISO 4633:2023(E)
5.3 Microbiological deterioration
The materials shall be resistant to microbiological deterioration if the application so requires. The test
methods and the requirements shall be as specified in national standards.
5.4 Dimensional tolerances
Tolerances shall be specified from the appropriate classes in ISO 3302-1.
5.5 Imperfections and defects
The seals shall be free of defects or irregularities which can affect their function. Classification of
imperfections shall be in accordance with ISO 9691, as follows:
— surface imperfections in zones involved in the sealing function, as described in ISO 9691:1992, 4.1.1,
shall be considered as defects;
— surface imperfections in zones not involved in the sealing function, as described in ISO 9691:1992,
4.1.2.1 b), shall not be considered as defects.
Major surface imperfections in zones not involved in the sealing function, as described in ISO 9691:1992,
4.1.2.1 a), can be considered as defects. This shall be agreed upon between the interested parties, the
acceptance criteria depend upon the seal type or design.
Internal imperfections as described in ISO 9691:1992, 4.2 can be considered as defects. The compressive
force referred to in ISO 9691:1992 can be determined in accordance with ISO 7743. The acceptable
limiting values of the compressive force shall be agreed upon between the interested parties. These
values depend upon the seal type or design.
5.6 Hardness
When determined by the micro-test method specified in ISO 48-2, the hardness shall comply with the
requirements given in Table 2.
If the dimensions of a seal are appropriate, the normal test method specified in ISO 48-2 can be used
provided that the micro-test method is used for reference purposes.
For the same seal, or along the greatest length of an extruded profile cut to make the seal, the difference
between the minimum and maximum hardness shall not be more than 5 IRHD-M. Each value shall be
within the specified tolerances.
5.7 Tensile strength and elongation at break
The tensile strength and elongation at break shall be determined by the method specified in ISO 37.
Dumb-bell-shaped test pieces of type 1, 2, 3, or 4 shall be used. Type 2 is the preferred type. The test
report shall state the dumb-bell type whenever type 2 is not used.
The tensile strength and the elongation at break shall comply with the requirements given in Table 2.
5.8 Compression set in air
5.8.1 General
If the test piece is taken from a seal, then the measurement shall be carried out as far as possible in the
direction of compression of the seal in service.
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ISO 4633:2023(E)
5.8.2 Compression set a
...