Clothing for protection against heat and flame — Determination of heat transmission on exposure to both flame and radiant heat

This document specifies a test method for measuring the heat transferred through horizontally mounted flame-resistant textile materials when exposed to a combination of convective and radiant heat. The exposure conditions are adjusted to be approximately a 50/50 mixture of pure convective heat and pure radiant heat. The total exposure heat flux is 84 kW/m2. This test method is applicable to any type of sheet material used either as a single layer or in a multilayer construction when all structures or sub-assemblies are made of flame-resistant materials. It does not apply to materials that are not flame resistant. This test method does not apply to the evaluation of materials exposed to any other type of thermal energy sources, such as radiant heat only or flame contact only. ISO 6942 is applicable when evaluating materials for exposure to radiant heat only. ISO 9151 is applicable when evaluating materials due to flame contact only. NOTE Some, but not all, textiles materials can ignite and continue to burn after exposure to the convective and radiant heat produced by this test method.

Vêtements de protection contre la chaleur et la flamme — Détermination de la transmission de chaleur lors de l'exposition simultanée à une flamme et à une source de chaleur radiante

General Information

Status
Published
Publication Date
07-Oct-2019
Current Stage
9020 - International Standard under periodical review
Start Date
15-Oct-2024
Completion Date
15-Oct-2024
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ISO 17492:2019 - Clothing for protection against heat and flame -- Determination of heat transmission on exposure to both flame and radiant heat
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INTERNATIONAL ISO
STANDARD 17492
Second edition
2019-10
Clothing for protection against heat
and flame — Determination of heat
transmission on exposure to both
flame and radiant heat
Vêtements de protection contre la chaleur et la flamme —
Détermination de la transmission de chaleur lors de l'exposition
simultanée à une flamme et à une source de chaleur radiante
Reference number
©
ISO 2019
© ISO 2019
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
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Apparatus . 4
6 Precautions . 8
7 Sampling . 9
7.1 Specimen dimensions . 9
7.2 Number of specimens . 9
8 Conditioning and testing atmospheres . 9
8.1 Conditioning atmosphere . 9
8.2 Testing atmosphere. 9
9 Test procedure . 9
9.1 Initial set up and calibration procedures . 9
9.1.1 Initial set up of the system and alignment of burner flames . 9
9.1.2 Initial setting of the 50/50 mix of convective and radiant heat . 9
9.1.3 Setting the radiant heat from the lamps . 9
9.1.4 Setting the total exposure heat flux .10
9.2 Sensor care .10
9.2.1 Sensor care .10
9.2.2 Sensor inspection .10
9.2.3 Surface reconditioning.10
9.3 Specimen holder care .11
9.4 Computer processing of data .11
9.5 Test specimen mounting .12
9.5.1 Single layer specimens .12
9.5.2 Multilayer assembly specimens .12
9.6 Test specimen exposure when both TPI and HTI(DE) are measured .12
9.7 Test specimen exposure when only HTI(DE) is measured .13
10 Expression of results .13
10.1 Selection of analysis method .13
10.2 Thermal protection index analysis method .13
10.2.1 Time to onset of burn injury .13
10.2.2 Thermal protection index .13
10.3 HTI(DE) analysis method .14
10.4 Response to convective and radiant heat exposure .14
11 Interlaboratory test data .14
12 Test report .14
Annex A (informative) Availability of materials .15
Annex B (informative) Basis of sensor calibration .17
Annex C (informative) Interlaboratory test data .18
Bibliography .19
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 94, Personal safety — Personal protective
equipment, Subcommittee SC 13, Protective clothing.
This second edition cancels and replaces the first edition (ISO 17492:2003), which has been technically
revised. It also incorporates the Technical Corrigendum ISO 17492:2003/Cor.1:2004. The main changes
compared with the previous edition are as follows:
— technical modifications and rewording have been made to all clauses, including to Annexes A and B;
— Clauses 5 to 12 have been renumbered;
— modifications have been made to Figures 1, 2 and 3.
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 2019 – All rights reserved

Introduction
The measurement of the thermal energy transferred from the exterior of a material to the interior
when exposed to a thermal hazard can be a significant factor in determining the level of protection or
insulation provided by an assembly. While full-scale test methods are a better means of determining
how an assembly performs, small scale tests such as those described in ISO 6942 and ISO 9151 can be
used in establishing benchmarks of performance for the materials from which these assemblies are
made. These tests enable the user of a material to anticipate how the properties of a particular material
could affect the performance of the assembly when exposed to a high heat flux.
The purpose of an assembly for thermal protection is to prevent or reduce the potential for skin burn
injury to the wearer. The performance of a product can be determined by comparing the total exposure
energy to that which is transferred through the protective material to a known point where the thermal
exposure would produce a burn injury in human tissue. The total exposure energy required to cause
the onset of a second-degree burn in human tissue is identified as the thermal protection index (TPI).
In the TPI analysis of the data, the specimen is exposed to steady heat until the energy transferred
through the specimen is equivalent to the energy that would cause the onset of a second-degree burn
injury (e.g. a blister).
Other uses include comparison of the insulation from a high-temperature exposure in terms other than
the response of human tissue to heat exposure. For these uses, an alternate method of evaluating the
heat transfer is provided. The total energy transferred that causes a temperature rise of the copper
sensor by 12 °C and 24 °C is determined as the heat transfer index (HTI). In the HTI analysis of the data,
the specimen is exposed to heat until a specified amount of energy is transferred. This is a measure of
the insulation performance and thermal capacity of the specimen.
Unlike what is described in ISO 6942 or ISO 9151, the heat source in this test method is approximately
50 % radiant heat and 50 % convective heat. This equalized radiant/convective output is set to a
thermal energy exposure having a heat flux of 84 kW/m . The magnitude of this heat flux is intended
to determine the performance of the specimen when exposed to both the high temperature radiation
and hot gases that exist in actual fire situations. The level of this heat flux represents a moderatel
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