ISO 24131-1:2023

Internal protection by polymeric lining for ductile iron pipes - Requirements and test methods - Part 1: Polyurethane lining

This document specifies the requirements and test methods applicable to factory applied internal polyurethane lining for ductile iron pipes according to ISO 2531, ISO 7186 and ISO 16631. It covers internal linings for use in the conveyance of raw water, potable water and sewage water for operating temperature up to 50 °C.

Protection interne des tuyaux en fonte ductile par revêtement polymérique — Exigences et méthodes d'essai — Partie 1: Revêtement polymérique

General Information

• Status: Published
• Publication Date: 30-Mar-2023
• ICS: 23.040.10 - Iron and steel pipes
• Technical Committee: ISO/TC 5/SC 2 - Cast iron pipes, fittings and their joints
• Drafting Committee: ISO/TC 5/SC 2 - Cast iron pipes, fittings and their joints
• Current Stage: 6060 - International Standard published
• Start Date: 31-Mar-2023
• Due Date: 28-Apr-2024
• Completion Date: 31-Mar-2023

Overview

ISO 24131-1:2023 specifies requirements and test methods for factory-applied polyurethane internal linings for ductile iron pipes (per ISO 2531, ISO 7186 and ISO 16631). The standard covers linings intended for the conveyance of raw water, potable water and sewage at operating temperatures up to 50 °C. It establishes technical and performance criteria, routine and performance test regimes, and quality assurance guidance for manufacturers and testing laboratories.

Key Topics

• Scope and definitions: Clear terms for polyurethane lining, cross-linkage, non-porosity (holiday testing), adhesion, minimum lining thickness, chalking and more.
• Technical requirements:
  • Surface preparation: Clean, dry substrates; maintain surface temperature above dew point; manufacturer responsibility to demonstrate fitness-for-purpose.
  • Surface roughness and appearance: Requirements for substrate profile and visual inspection criteria.
  • Lining thickness and protection of pipe ends: Minimum thickness control and end/coating protection for spigots and sockets.
  • Adhesion and cross-linkage: Pull-off adhesion tests and verification of cure chemistry.
  • Non-porosity (holiday) testing: Electrical puncture testing to confirm continuity of the lining.
  • Hardness and mechanical properties: Shore hardness, elongation at break, resistance to ovalization.
• Performance requirements:
  • Abrasion and chemical resistance (specifically for sewage applications).
  • Indirect impact resistance and resistance to hot water.
  • Specific lining resistance (electrical surface resistance).
• Test methods:
  • Routine tests for process control (e.g., thickness, adhesion, DSC, hardness, non-porosity).
  • Performance tests required on material/process changes (e.g., abrasion, chemical, impact, hot water).
• Quality assurance and handling: Normative Annex A (quality assurance) and informative Annex B (handling, transport, storage).

Applications

ISO 24131-1:2023 is used to:

• Specify acceptance criteria in procurement and contract documents for lined ductile iron pipes.
• Guide manufacturers of ductile iron pipes and lining applicators on production control and factory testing.
• Support QA/QC teams and independent testing laboratories performing routine and performance tests.
• Inform engineers, water utilities, and consultants selecting linings for potable water, raw water and sewage pipelines.

Who benefits: pipe manufacturers, coating system suppliers, municipal utilities, civil/pipe engineers, contractors, and compliance auditors.

Related standards

Key referenced standards include:

• ISO 2531, ISO 7186, ISO 16631 (ductile iron pipe system compatibility)
• ISO 4624 (pull-off adhesion)
• ISO 868 (Shore hardness)
• ISO 62, ISO 527-3 (water absorption, tensile properties)
• ISO 8501-1 / ISO 8503-1 / ISO 8502-3 (surface preparation and cleanliness)

Keywords: ISO 24131-1:2023, polyurethane lining, ductile iron pipes, internal protection, test methods, potable water lining, sewage pipe lining, factory applied lining.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 24131-1
First edition
2023-03
Internal protection by polymeric
lining for ductile iron pipes —
Requirements and test methods —
Part 1:
Polyurethane lining
Protection interne des tuyaux en fonte ductile par revêtement
polymérique — Exigences et méthodes d'essai —
Partie 1: Revêtement polymérique
Reference number
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Technical requirements . 3
4.1 General . 3
4.2 Surface preparation . 3
4.3 Surface roughness . 4
4.4 Lining appearance . 4
4.5 Lining thickness . 4
4.6 Adhesion . 4
4.7 Cross linkage . 4
4.8 Non-porosity . 5
4.9 Hardness . 5
4.10 Protection of pipe ends . 5
4.11 Marking . 5
4.12 Repairs . 5
5 Performance requirements . .6
5.1 General . 6
5.2 Materials in contact with water intended for human consumption . 6
5.3 Abrasion resistance only for sewage applications . 6
5.4 Chemical resistance only for sewage applications . 6
5.5 Indirect impact resistance . 6
5.6 Resistance to hot water . 6
5.7 Specific lining resistance . . 6
5.8 Resistance to ovalization . 7
5.9 Elongation at break . 7
6 Test methods . 7
6.1 Routine tests . . 7
6.1.1 Surface preparation . 7
6.1.2 Surface roughness . 7
6.1.3 Lining appearance . . 7
6.1.4 Lining thickness . 7
6.1.5 Adhesion . 7
6.1.6 Differential scanning calorimetry (DSC) . 8
6.1.7 Non-porosity . 8
6.1.8 Hardness . 8
6.1.9 Marking . . . 8
6.1.10 Repairs . 8
6.2 Performance test . 8
6.2.1 Abrasion resistance only for sewage applications . 8
6.2.2 Chemical resistance only for sewage applications . 8
6.2.3 Indirect impact resistance . 8
6.2.4 Resistance to hot water . 9
6.2.5 Specific lining resistance . 9
6.2.6 Resistance to ovalization . 10
6.2.7 Elongation at break . 10
Annex A (normative) Quality assurance .11
Annex B (informative) Handling, transportation and storage .13
Bibliography .14
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation 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 5, Ferrous metal pipes and metallic fittings,
Subcommittee SC 2, Cast iron pipes, fittings and their joints.
A list of all parts in the ISO 24131 series can be found on the ISO website.
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.
iv
Introduction
The ISO 24131 series specifies the requirements and test methods applicable to factory applied
polymeric linings for ductile iron pipes according to ISO 2531, ISO 7186 and ISO 16631. The ISO 24131
series is intended to include several types of polymeric linings.
v
INTERNATIONAL STANDARD ISO 24131-1:2023(E)
Internal protection by polymeric lining for ductile iron
pipes — Requirements and test methods —
Part 1:
Polyurethane lining
1 Scope
This document specifies the requirements and test methods applicable to factory applied internal
polyurethane lining for ductile iron pipes according to ISO 2531, ISO 7186 and ISO 16631.
It covers internal linings for use in the conveyance of raw water, potable water and sewage water for
operating temperature up to 50 °C.
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 62, Plastics — Determination of water absorption
ISO 527-3, Plastics — Determination of tensile properties — Part 3: Test conditions for films and sheets
ISO 868, Plastics and ebonite — Determination of indentation hardness by means of a durometer (Shore
hardness)
ISO 2531, Ductile iron pipes, fittings, accessories and their joints for water applications
ISO 4624, Paints and varnishes — Pull-off test for adhesion
ISO 7186:2011, Ductile iron products for sewerage applications
ISO 8503-1, Preparation of steel substrates before application of paints and related products — Surface
roughness characteristics of blast-cleaned steel substrates — Part 1: Specifications and definitions for ISO
surface profile comparators for the assessment of abrasive blast-cleaned surfaces
ISO 16631, Ductile iron pipes, fittings, accessories and their joints compatible with plastic (PVC or PE)
piping systems, for water applications and for plastic pipeline connections, repair and replacement
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 2531 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
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
polyurethane lining
factory applied lining which consists of polyurethane (3.2) on the inside of the pipe
Note 1 to entry: See Figure 1.
Key
1 gasket seat
2 pipe barrel
3 spigot end
4 lining
5 internal socket profile
Figure 1 — Location of the defined pipe areas
3.2
polyurethane
polymers made by combining diisocyanates and polyols
3.3
operating temperature
applicable temperatures under which the product maintains its properties
3.4
chalking
superficial reaction of polyurethane lining (3.1) due to exposure to UV-radiation
Note 1 to entry: The process is confined to the surface only and results in a dulling of the surface.
3.5
minimum lining thickness
minimum value of the lining thickness measured at the lined item
3.6
adhesion
force per unit area, applied perpendicular to the surface, which is necessary to separate the lining from
its substrate
3.7
cross linkage
chemical reaction between polyurethane (3.2) resin and hardener to form the final cured lining
3.8
non-porosity
absence of electrical puncture in a high voltage test (holiday test) under defined test conditions
3.9
hardness
resistance of the lining to the penetration of a ball under defined test conditions
3.10
protection of pipe ends
factory applied coating/lining on spigot end and internal socket profile of pipes
Note 1 to entry: See Figure 1.
3.11
abrasion resistance
ability of materials and structures to withstand abrasion
3.12
indirect impact resistance
impact energy applied from outside of the pipe with deformation to which a lining can withstand
without damage under defined test conditions
3.13
specific lining resistance
surface related electric resistance of the lining perpendicular to the pipe wall
3.14
ovalization
100 times the measured vertical deflection, (caused by the applied load) divided by the measured pipe
external diameter
3.15
routine test
test carried out to control the manufacturing process
Note 1 to entry: The frequency of the test is defined by this document or the manufacturer.
3.16
performance test
test which is done once and thereafter only when there is a change in the lining material or lining
process
4 Technical requirements
4.1 General
The following technical requirements shall be demonstrated by routine tests applied in production,
on in-process and finished lined products with defined frequency. Routine tests shall be in accordance
with the overview of requirements provided in Table A.2.
Quality assurance for polyurethane lining shall be in accordance with Annex A.
4.2 Surface preparation
Prior to lining application, all surfaces to be lined shall be substantially clean and free from oil, grease
and moisture.
In cold weather, or anytime when moisture tends to condense on the surface of the pipe, it shall be
uniformly warmed for sufficient time to dry prior to cleaning. The surface temperature shall be
maintained at least 3 °C above the dew point.
Surface preparation shall be designed in order to reach the required performances specified in this
document. It is the responsibility of the manufacturer to demonstrate the fitness for purpose of surface
preparation technology and to put in place a quality control procedure to ensure the stability of those
performances.
NOTE The requirements of Class Sa 2.5 of ISO 8501-1 and ≤ Rating 3 dust quantity and Class 2 for dust size of
ISO 8502-3 can be applied.
4.3 Surface roughness
The surface roughness Ra in accordance with ISO 8503-1 shall be at least 12,5 μm which is equivalent
to anchored profile Rz of 63 μm or higher if required by the lining material provider or manufacturer.
4.4 Lining appearance
The lining of the final product shall be of
— uniform colour, except for permitted marking;
— uniform appearance and smoothness, except for allowable repairs;
— free of visible defects (i.e. pinholes, bubbles, blisters, wrinkles, cracks or voids).
Slight superficial colour variations due to repairs or long exposure to sunlight (chal
...