ISO 23648

• Abstract:

  This document specifies a test method for assessing the reaction-to-fire performance of water-filled plastic pipes and fibre reinforced plastic (FRP) pipes in the impinging flame condition.

• Status: Not Published
• ICS: 13.220.40 - Ignitability and burning behaviour of materials and products
• ICS: 23.040.20 - Plastics pipes
• Technical Committee: ISO/TC 61/SC 4 - Burning behaviour
• Drafting Committee: ISO/TC 61/SC 4 - Burning behaviour
• Current Stage: 6000 - International Standard under publication
• Start Date: 02-Sep-2026
• Completion Date: 19-Sep-2026

Overview

ISO 23648: Plastics - Impinging Flame Test on Water-Filled Plastic Pipes specifies a standardized test method for assessing the fire performance of water-filled plastic pipes and fibre reinforced plastic (FRP) pipes under impinging flame conditions. Developed by ISO Technical Committee ISO/TC 61, Subcommittee SC 4 (Burning behaviour), this standard ensures reliable, consistent evaluation of the reaction-to-fire properties of plastic piping systems, especially those used in demanding applications such as maritime environments.

ISO 23648 provides guidance for manufacturers, testing laboratories, and regulating authorities aiming to demonstrate compliance with international safety guidelines related to fire protection when using plastic pipes. It builds upon previous guidelines, notably IMO A.753(18), to offer comprehensive test procedures for water-filled plastic pipes, especially in ship applications where fire resistance is critical.

Key Topics

• Scope and Purpose

  • Focuses on testing water-filled plastic and FRP pipes exposed to direct flames.
  • Evaluates the ability of pipes to resist leakage and maintain integrity under fire conditions.

• Test Principle

  • The test involves subjecting pipe specimens filled with water at a specified pressure to predetermined flame conditions for a set duration.
  • The main assessment criteria are containment of water (no significant leakage) and maintenance of internal pressure during and after exposure.

• Test Apparatus and Conditions

  • Describes detailed requirements for burners, fuel gas supply, specimen supports, thermocouples, and pressure monitoring devices.
  • Specifies preconditioning of specimens at controlled temperature and humidity.

• Test Procedure

  • Outlines step-by-step process: specimen preparation, pre-test inspections, heat application, and post-exposure evaluations.
  • Defines acceptance criteria based on allowable leakage and pressure performance.

• Reporting and Documentation

  • Specifies what information must be included in the test report: product description, testing conditions, results, and compliance statement.

Applications

The ISO 23648 standard is highly relevant where plastic piping is subject to stringent fire safety standards. It is especially crucial for:

• Maritime Industry

  • Testing pipes used for fresh water, sea water, drain, and liquid cargo systems onboard ships.
  • Demonstrating compliance with International Maritime Organization (IMO) fire safety requirements.

• Chemical Processing and Offshore Engineering

  • Assessing the suitability of FRP and plastic piping for chemical and hazardous environments where fire exposure risk is present.

• Building and Construction

  • Ensuring plastic piping systems in critical infrastructure can meet fire safety codes.
  • Supporting manufacturers in certifying products for use in high-risk areas, such as basements or parking structures.

• Accredited Testing and Certification

  • Provides laboratories with a clear, repeatable method to test and certify pipes against international reaction-to-fire performance benchmarks.

Related Standards

ISO 23648 references and aligns with several key international standards, including:

• ISO 13943: Fire safety - Vocabulary, for consistent terminology in fire testing.
• ISO 14934-3: Fire tests - Calibration and use of heat flux meters - Part 3: Secondary calibration method, ensuring accurate measurement of heat exposure.

Other related guidelines and standards:

• IMO A.753(18): International Maritime Organization's guidelines for application of plastic pipes on ships, including fire test requirements.
• ISO/IEC Directives: Provides rules for drafting and maintaining ISO documents, ensuring methodological consistency.

---

By following ISO 23648, stakeholders ensure that plastic and FRP pipe products meet essential fire resistance requirements, enhancing safety and compliance in critical water piping applications worldwide. For manufacturers and users alike, adherence to this standard contributes to risk reduction, regulatory acceptance, and increased confidence in piping system performance under fire exposure.

FINAL DRAFT
International
Standard
ISO/FDIS 23648
ISO/TC 61/SC 4
Plastics — Impinging flame test on
Secretariat: BSI
water-filled plastic pipes
Voting begins on:
2026-07-07
Voting terminates on:
2026-09-01
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 SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
ISO/FDIS 23648:2026(en) © ISO 2026

FINAL DRAFT
ISO/FDIS 23648:2026(en)
International
Standard
ISO/FDIS 23648
ISO/TC 61/SC 4
Plastics — Impinging flame test on
Secretariat: BSI
water-filled plastic pipes
Voting begins on:
Voting terminates on:
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 SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
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 Reference number
ISO/FDIS 23648:2026(en) © ISO 2026

ii
ISO/FDIS 23648:2026(en)
Contents  Page
Foreword .iv
Introduction .v
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Principle . 1
5  Apparatus . 1
5.1 Heat source .1
5.2 Fuel gas supply system .2
5.3 Test specimen support . .3
5.4 Water supplying system .3
5.5 Timing device .3
5.6 Heat flux meter .3
5.7 Thermocouple .3
5.8 Closing devices of specimen .4
6  Test specimen . 4
6.1 Dimensions .4
6.2 Joints .4
6.3 Insulation .4
7  Conditioning of specimen . 4
8  Test method . 4
8.1 Test conditions .4
8.2 Heat flux measurement .4
8.3 Preparation .4
8.4 Test procedure .5
9  Acceptance criteria . 5
10  Test report . 5
11  Precision of the test . 6
Annex A (informative)  Examples of view of the test, measurement of water temperature and
pressure during the test . 7
Bibliography . 9

iii
ISO/FDIS 23648:2026(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 61, Plastics, Subcommittee SC 4, Burning
behaviour.
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
ISO/FDIS 23648:2026(en)
Introduction
Plastic pipes and fibre reinforced plastics pipes (FRP pipes) exhibit corrosion resistance against water,
including sea water and liquid chemicals. These pipes have been used on ships in various applications, such
as piping for supplying fresh water, sanitary and drain piping, sea-water piping and liquid cargo piping.
The International Maritime Organization (IMO) adopted guidelines on use of plastic pipes (IMO Assembly
[1]
resolution A.753(18) as amended ). These guidelines contain requirements on the fire performance of
plastic pipes and of FRP pipes to be used on-board ships. These guidelines also contain a brief explanation
of the test procedures on a fire performance test for liquid-filled plastic pipes in the Appendix 2 of IMO
A.753(18). However, the description of the fire test in the current guideline is very short and insufficient to
conduct the test in a uniform and consistent manner.
[1]
This document was developed based on the IMO A.753(18) and provides detailed descriptions of the fire
test methods applicable to plastic pipes and FRP pipes used on ships.

v
FINAL DRAFT International Standard ISO/FDIS 23648:2026(en)
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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.
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Formatted: French (France)
ISO/FDIS 23648:20252026(en)
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
E-mail: [e-mail]
Website: www.iso.org
Formatted: English (United Kingdom)
Formatted: English (United Kingdom)
Published in Switzerland
Formatted: English (United Kingdom)

iii
ISO/FDIS 23648:20252026(en)
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
5.1 Heat source. 1
5.2 Fuel gas supply system . 2
5.3 Test specimen support . 3
5.4 Water supplying system . 3
5.5 Timing device . 3
5.6 Heat flux meter . 3
5.7 Thermocouple . 3
5.8 Closing devices of specimen . 3
6 Test specimen . 4
6.1 Dimensions. 4
6.2 Joints . 4
6.3 Insulation . 4
7 Conditioning of specimen . 4
8 Test method . 4
8.1 Test conditions . 4
8.2 Heat flux measurement . 4
8.3 Preparation . 4
8.4 Test procedure . 5
9 Acceptance criteria. 5
10 Test report . 5
11 Precision of the test . 6
Annex A (informative) Examples of view of the test, measurement of water temperature and
pressure during the test . 7
Bibliography . 9
Foreword . vi
Introduction . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
5.1 Heat source. 1
5.2 Fuel gas supply system . 3
5.3 Test specimen support . 3
5.4 Water supplying system . 4
iv
ISO/FDIS 23648:20252026(en)
5.5 Timing device . 4
5.6 Heat flux meter . 4
5.7 Thermocouple . 4
5.8 Closing devices of specimen . 5
6 Test specimen . 5
6.1 Dimensions. 5
6.2 Joints . 5
6.3 Insulation . 5
7 Conditioning of specimen . 5
8 Test method . 5
8.1 Test conditions . 5
8.2 Heat flux measurement . 5
8.3 Preparation . 5
8.4 Test procedure . 6
9 Acceptance criteria. 6
10 Test report . 7
11 Precision of the test . 7
Annex A (informative) Examples of view of the test, measurement of water temperature and
pressure during the test . 8
Bibliography . 11

v
ISO/FDIS 23648:20252026(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).
Formatted: English (United Kingdom)
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.htmlwww.iso.org/iso/foreword.html.
Formatted: English (United Kingdom)
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 4, Burning
behaviour.
Any feedback or questions on this document should be directed to the user’s national standards body. A
Formatted: English (United Kingdom)
complete listing of these bodies can be found at www.iso.org/members.htmlwww.iso.org/members.html.
Formatted: English (United Kingdom)
vi
ISO/FDIS 23648:20252026(en)
Introduction
Plastic pipes and fibre reinforced plastics pipes (FRP pipes) exhibit corrosion resistance against water,
including sea water and liquid chemicals. These pipes have been used on ships in various applications, such
as piping for su
...