ISO 9772:2020

Cellular plastics - Determination of horizontal burning characteristics of small specimens subjected to a small flame

This document specifies a small-scale laboratory screening procedure for comparing the relative burning characteristics of horizontally oriented, small cellular plastic specimens having a density less than 250 kg⋅m−3 determined in accordance with ISO 845, when exposed to a small-flame ignition source. NOTE Another International Standard which covers flexible cellular plastic and cellular rubber is ISO 3582[2]. This method of test is intended for quality assurance and limited product evaluation of cellular plastic materials under controlled laboratory conditions, and is not intended to assess the fire behaviour of, for example, building materials or furnishings under actual fire conditions. The optional classification system described in Annex A is intended for the pre-selection of cellular plastic materials for products, including the determination of the ranges of material parameters that give the same classification (see 6.1).

Plastiques alvéolaires — Détermination des caractéristiques de combustion de petites éprouvettes en position horizontale, soumises à une petite flamme

Penjeni polimerni materiali - Ugotavljanje gorilnih lastnosti majhnih preskušancev, izpostavljenih majhnemu plamenu, s horizontalno metodo

Ta dokument določa manjše postopke presejanja v laboratoriju za primerjavo relativnih gorilnih lastnosti vodoravnih in majhnih preskušancev iz penjenih polimernih materialov z gostoto manj kot 250 kg⋅m−3, določeno v skladu s standardom ISO 845, kadar so izpostavljeni viru vžiga z majhnim plamenom.
OPOMBA: Prilagodljivi penjeni polimerni materiali in gume so zajeti v drugem mednarodnem standardu (ISO 3582[2]).
Ta metoda preskušanja je namenjena zagotavljanju kakovosti in omejenemu vrednotenju izdelkov iz penjenih polimernih materialov pod nadzorovanimi laboratorijskimi pogoji ter ni namenjena ocenjevanju, kako se npr. gradbeni material ali oprema obnaša v požaru pod dejanskimi pogoji požara.
Neobvezni sistem razvrščanja, opisan v dodatku A, je namenjen predhodni izbiri penjenih polimernih materialov za izdelke, vključno z določanjem obsegov parametrov materiala, ki zagotavljajo enako razvrstitev (glej točko 6.1).

General Information

• Status: Published
• Publication Date: 23-Nov-2020
• ICS: 13.220.40 - Ignitability and burning behaviour of materials and products
• ICS: 83.100 - Cellular materials
• Technical Committee: ISO/TC 61/SC 4 - Burning behaviour
• Drafting Committee: ISO/TC 61/SC 4/WG 8 - Ignitability and fire growth
• Current Stage: 9020 - International Standard under periodical review
• Start Date: 15-Oct-2025
• Completion Date: 15-Oct-2025
• Ref Project: SIST ISO 9772:2022 - Cellular plastics - Determination of horizontal burning characteristics of small specimens subjected to a small flame

Relations

• Revises: ISO 9772:2012 - Cellular plastics - Determination of horizontal burning characteristics of small specimens subjected to a small flame
• Effective Date: 23-Apr-2020

Overview

ISO 9772:2020 - "Cellular plastics - Determination of horizontal burning characteristics of small specimens subjected to a small flame" - is a small‑scale laboratory screening method for comparing the horizontal burning behaviour of cellular plastics with apparent density less than 250 kg·m−3 (per ISO 845). It defines apparatus, specimen preparation, conditioning, test procedure, measurements and reporting for quality assurance and limited product evaluation. The method is intended for controlled laboratory comparisons and pre‑selection of materials, not for predicting full-scale fire behaviour in building or furnishing fires.

Key topics and technical requirements

• Scope and purpose: Horizontal orientation testing of small cellular plastic specimens; optional classification system for pre‑selection (Annex A).
• Material limits: Applies to cellular plastics with density < 250 kg·m−3 (ISO 845). Flexible cellular plastics and cellular rubber are covered elsewhere (ISO 3582).
• Apparatus:
  • Draught‑free test enclosure (fume hood) with dark interior and extraction for safety.
  • Diffusion flame burner P/PF2 as specified in ISO 10093 (barrel length (100 ± 10) mm; internal diameter (9,5 ± 0,3) mm) with a wing top opening (48 ± 1) mm × (1,3 ± 0,05) mm.
  • Wire cloth support (approx. 215 mm × 75 mm) with plain weave, ~6,4 mm mesh and ~0,9 mm wire (ASTM E2016).
  • Positioning equipment to hold gauze horizontal and maintain specimen 13 ± 1 mm above burner; gauze ~175 ± 25 mm above cotton indicator.
  • Timing devices, measuring scale and specified cotton indicator.
• Procedure elements: Specimen preparation and conditioning, burner and specimen positioning, ignition and burning sequence, measurements of afterflame and afterglow times, damaged lengths, repeat testing rules (including provisions when specimens shrink without igniting), and calculations.
• Precision and reporting: Requirements for number of valid tests, heat‑age comparison, and test report contents are defined.

Applications and users

• Practical uses: Material selection, quality control, formulation changes, process control, and pre‑selection of cellular plastics for components in appliances and devices. Useful for identifying relative burning tendencies under a small‑flame ignition in a horizontal orientation.
• Who uses it: Materials scientists, product designers, safety engineers, quality managers, test laboratories, and standards bodies involved in plastics, packaging, transport and appliance manufacturing.

Related standards

• ISO 845 - determination of apparent density
• ISO 10093 - standard ignition sources (burner specification)
• ISO 13943 - fire safety vocabulary
• ISO 3582 - flexible cellular plastics and cellular rubber (related method)
• ASTM E2016 - wire cloth specification
• IEC 60695-11-3 - test flames (referenced for flame characteristics)

Keywords: ISO 9772:2020, cellular plastics, horizontal burning, small flame, burning characteristics, fire test, laboratory screening, ISO 845, quality assurance.

Standards Content (Sample)

SLOVENSKI STANDARD
01-marec-2022
Penjeni polimerni materiali - Ugotavljanje gorilnih lastnosti majhnih preskušancev,
izpostavljenih majhnemu plamenu, s horizontalno metodo
Cellular plastics - Determination of horizontal burning characteristics of small specimens
subjected to a small flame
Plastiques alvéolaires - Détermination des caractéristiques de combustion de petites
éprouvettes en position horizontale, soumises à une petite flamme
Ta slovenski standard je istoveten z: ISO 9772:2020
ICS:
13.220.40 Sposobnost vžiga in Ignitability and burning
obnašanje materialov in behaviour of materials and
proizvodov pri gorenju products
83.100 Penjeni polimeri Cellular materials
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 9772
Fourth edition
2020-11
Cellular plastics — Determination of
horizontal burning characteristics of
small specimens subjected to a small
flame
Plastiques alvéolaires — Détermination des caractéristiques de
combustion de petites éprouvettes en position horizontale, soumises à
une petite flamme
Reference number
©
ISO 2020
© ISO 2020
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 © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Significance of test . 2
5 Apparatus . 3
6 Specimens . 7
6.1 Extended application of test results . 7
6.2 Preparation of specimens . 8
7 Conditioning . 8
7.1 Specimens . 8
7.2 Cotton indicator . 9
8 Test procedure . 9
8.1 Adjustment of the flame . 9
8.2 Adjustment of specimen support .10
8.3 Positioning of cotton indicator .11
8.4 Positioning of specimen .11
8.5 Burning procedure .11
8.6 Measurements .11
8.7 Preparation for the next test .12
9 Calculations.12
10 Precision .13
11 Test report .13
Annex A (informative) Classification system .14
Bibliography .16
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 61, Plastics, Subcommittee SC 4, Burning
behaviour.
This fourth edition cancels and replaces the third edition (ISO 9772:2012), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— better definitions of positions of specimen on wire mesh and of burner have been provided;
— requirements for materials that show different damaged lengths on top and bottom faces of the
specimen have been specified;
— dimensions of cotton indicator have been reduced;
— reference to ASTM E2016 has been added.
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 2020 – All rights reserved

Introduction
Cellular plastics are widely used in products for packaging, building, housing, industry and transport,
in various applications. The burning behaviour of cellular plastics is a concern for the fire safety of these
products. This document gives a method for the determination of the burning behaviour of cellular
plastics using a small flame source.
The burning behaviour of cellular plastics is influenced by the test specimen orientation (vertical or
horizontal). This method of test evaluates specimens which are oriented horizontally.
The method described is also intended as a pre-selection test for materials used for components of
devices and appliances. The final acceptance of the material is dependent upon its use in complete
equipment that conforms with the standards applicable to such equipment.
It should be noted that the test results obtained by the test specified in this document alone cannot
represent all the aspects of the fire hazard of cellular plastics in end-use conditions.
INTERNATIONAL STANDARD ISO 9772:2020(E)
Cellular plastics — Determination of horizontal burning
characteristics of small specimens subjected to a small
flame
1 Scope
1.1 This document specifies a small-scale laboratory screening procedure for comparing the relative
burning characteristics of horizontally oriented, small cellular plastic specimens having a density less
−3
than 250 kg⋅m determined in accordance with ISO 845, when exposed to a small-flame ignition source.
[2]
NOTE Another International Standard which covers flexible cellular plastic and cellular rubber is ISO 3582 .
1.2 This method of test is intended for quality assurance and limited product evaluation of cellular
plastic materials under controlled laboratory conditions, and is not intended to assess the fire behaviour
of, for example, building materials or furnishings under actual fire conditions.
1.3 The optional classification system described in Annex A is intended for the pre-selection of cellular
plastic materials for products, including the determination of the ranges of material parameters that give
the same classification (see 6.1).
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 845, Cellular plastics and rubbers — Determination of apparent density
ISO 1923, Cellular plastics and rubbers — Determination of linear dimensions
ISO 10093:2020, Plastics — Fire tests — Standard ignition sources
ISO 13943, Fire safety — Vocabulary
ASTM E2016, Standard Specification for Industrial Woven Wire Cloth
IEC 60695-11-3, Fire hazard testing — Part 11-3: Test flames — 500 W flames — Apparatus and
confirmational test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 13943 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
afterflame
flame that persists after the ignition source has been removed
[SOURCE: ISO 13943:2017, 3.11]
3.2
afterflame time
length of time for which an afterflame (3.1) persists under specified conditions
[SOURCE: ISO 13943:2017, 3.12]
3.3
afterglow
persistence of glowing combustion after both removal of the ignition source and the cessation of any
flaming combustion
[SOURCE: ISO 13943:2017, 3.13]
3.4
afterglow time
length of time for which an afterglow (3.3) persists under specified conditions
[SOURCE: ISO 13943:2017, 3.14]
3.5
extended application of test results
process of predicting a test result, on the basis of one or more existing test results obtained by the
same test, for a product for which a property and/or the intended end-use application(s) are subject to
variation
3.6
draught-free environment
space in which the results of experiments are not significantly affected by the local air speed
4 Significance of test
4.1 Tests conducted on a material under the conditions specified can be of considerable value when
comparing the horizontal burning characteristics of different materials, controlling manufacturing
processes or assessing any changes in formulation or treatment prior to use.
4.2 Assessment of fire hazard requires consideration of factors such as fuel contribution, intensity
of burning (rate of heat release) and products of combustion, as well as environmental factors such as
intensity of source, orientation of exposed material and ventilation conditions.
4.3 The horizontal burning characteristics, as measured by this test procedure, might be affected by
factors such as density, any anisotropy of the cellular material, its melting characteristics, its colour and
its thickness.
4.4 Certain materials might shrink from the applied flame without igniting. In this event, the test results
are not valid, and additional test specimens are required to obtain 10 valid test results. If this proves
impossible due to non-ignition of all the specimens, then this test is not suitable for these materials.
4.5 The horizontal burning characteristics of some cellular plastic materials might change with time,
and tests are therefore conducted before and after heat ageing.
2 © ISO 2020 – All rights reserved

5 Apparatus
5.1 A laboratory fume hood, having an inside volume of at least 0,5 m is used. The chamber shall
permit observation of tests in progress and shall provide a draught-free environment whilst allowing
normal thermal circulation of air past the test specimen during burning. The inside surfaces of
the chamber shall be of a dark colour. When a light meter, facing towards the rear of the chamber, is
positioned in place of the test specimen, the recorded light level shall be less than 20 lux.
For safety and convenience, this enclosure (which can be completely closed) shall be fitted with an
extraction device, such as an exhaust fan, to remove products of combustion that might be toxic. The
extraction device shall be turned off during the test and turned on again immediately after the test to
remove the fire effluents. A positive closing damper might be needed.
NOTE The amount of oxygen available to support combustion is naturally important for the conduct of these
flame tests. For tests conducted by this method when burning times are protracted, chamber sizes greater than
0,5 m might be needed to provide reproducible results.
5.2 P/PF2 laboratory burner, as specified in ISO 10093. The burner shall be the diffusion flame
burner specified in ISO 10093:2020, 11.3, having a barrel length of (100 ± 10) mm and an internal
diameter of (9,5 ± 0,3) mm. The barrel shall not be equipped with an end attachment, such as a stabilizer.
5.3 The burner shall be fitted with a burner wing top, having an opening of internal length (48 ± 1) mm
and internal width (1,3 ± 0,05) mm (see Figure 1).
To ensure the wing top opening is uniform in width, one option is to slide a (1,3 ± 0,05) mm steel wire
or spacer along its length.
5.4 The support gauze shall be a wire cloth of plain weave, approximately 215 mm long by 75 mm
wide, as shown in Figure 2. It shall consist of (6,4 ± 0,5) mm mesh gauze constructed of (0,9 ± 0,1) mm
diameter stainless steel, plain or low carbon steel wire. The cloth-mesh and wire diameter shall be
determined as described in the Standard Specification for Industrial Woven Wire Cloth, ASTM E2016.
5.5 The gauge-support holder shall consist of two laboratory ring stands with clamps adjustable to
the desired angles and heights. The gauze-support holder shall be constructed from aluminium or steel
and shall satisfy the following conditions:
— the long axis of the gauze shall be maintained to within 1° of the horizontal;
— the nearest end of the specimen shall be (13 ± 1) mm above the burner wing top (see Figure 2);
— the space both above and below the specimen shall not be obstructed;
— a means shall be provided for positioning the burner in the correct location relative to the specimen,
preferably with a sliding mechanism and a stop to allow fast movement of the burner flame towards
and away from the specimen;
— the gauze shal
...

INTERNATIONAL ISO
STANDARD 9772
Fourth edition
2020-11
Cellular plastics — Determination of
horizontal burning characteristics of
small specimens subjected to a small
flame
Plastiques alvéolaires — Détermination des caractéristiques de
combustion de petites éprouvettes en position horizontale, soumises à
une petite flamme
Reference number
©
ISO 2020
© ISO 2020
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 © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Significance of test . 2
5 Apparatus . 3
6 Specimens . 7
6.1 Extended application of test results . 7
6.2 Preparation of specimens . 8
7 Conditioning . 8
7.1 Specimens . 8
7.2 Cotton indicator . 9
8 Test procedure . 9
8.1 Adjustment of the flame . 9
8.2 Adjustment of specimen support .10
8.3 Positioning of cotton indicator .11
8.4 Positioning of specimen .11
8.5 Burning procedure .11
8.6 Measurements .11
8.7 Preparation for the next test .12
9 Calculations.12
10 Precision .13
11 Test report .13
Annex A (informative) Classification system .14
Bibliography .16
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 61, Plastics, Subcommittee SC 4, Burning
behaviour.
This fourth edition cancels and replaces the third edition (ISO 9772:2012), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— better definitions of positions of specimen on wire mesh and of burner have been provided;
— requirements for materials that show different damaged lengths on top and bottom faces of the
specimen have been specified;
— dimensions of cotton indicator have been reduced;
— reference to ASTM E2016 has been added.
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 2020 – All rights reserved

Introduction
Cellular plastics are widely used in products for packaging, building, housing, industry and transport,
in various applications. The burning behaviour of cellular plastics is a concern for the fire safety of these
products. This document gives a method for the determination of the burning behaviour of cellular
plastics using a small flame source.
The burning behaviour of cellular plastics is influenced by the test specimen orientation (vertical or
horizontal). This method of test evaluates specimens which are oriented horizontally.
The method described is also intended as a pre-selection test for materials used for components of
devices and appliances. The final acceptance of the material is dependent upon its use in complete
equipment that conforms with the standards applicable to such equipment.
It should be noted that the test results obtained by the test specified in this document alone cannot
represent all the aspects of the fire hazard of cellular plastics in end-use conditions.
INTERNATIONAL STANDARD ISO 9772:2020(E)
Cellular plastics — Determination of horizontal burning
characteristics of small specimens subjected to a small
flame
1 Scope
1.1 This document specifies a small-scale laboratory screening procedure for comparing the relative
burning characteristics of horizontally oriented, small cellular plastic specimens having a density less
−3
than 250 kg⋅m determined in accordance with ISO 845, when exposed to a small-flame ignition source.
[2]
NOTE Another International Standard which covers flexible cellular plastic and cellular rubber is ISO 3582 .
1.2 This method of test is intended for quality assurance and limited product evaluation of cellular
plastic materials under controlled laboratory conditions, and is not intended to assess the fire behaviour
of, for example, building materials or furnishings under actual fire conditions.
1.3 The optional classification system described in Annex A is intended for the pre-selection of cellular
plastic materials for products, including the determination of the ranges of material parameters that give
the same classification (see 6.1).
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 845, Cellular plastics and rubbers — Determination of apparent density
ISO 1923, Cellular plastics and rubbers — Determination of linear dimensions
ISO 10093:2020, Plastics — Fire tests — Standard ignition sources
ISO 13943, Fire safety — Vocabulary
ASTM E2016, Standard Specification for Industrial Woven Wire Cloth
IEC 60695-11-3, Fire hazard testing — Part 11-3: Test flames — 500 W flames — Apparatus and
confirmational test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 13943 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
afterflame
flame that persists after the ignition source has been removed
[SOURCE: ISO 13943:2017, 3.11]
3.2
afterflame time
length of time for which an afterflame (3.1) persists under specified conditions
[SOURCE: ISO 13943:2017, 3.12]
3.3
afterglow
persistence of glowing combustion after both removal of the ignition source and the cessation of any
flaming combustion
[SOURCE: ISO 13943:2017, 3.13]
3.4
afterglow time
length of time for which an afterglow (3.3) persists under specified conditions
[SOURCE: ISO 13943:2017, 3.14]
3.5
extended application of test results
process of predicting a test result, on the basis of one or more existing test results obtained by the
same test, for a product for which a property and/or the intended end-use application(s) are subject to
variation
3.6
draught-free environment
space in which the results of experiments are not significantly affected by the local air speed
4 Significance of test
4.1 Tests conducted on a material under the conditions specified can be of considerable value when
comparing the horizontal burning characteristics of different materials, controlling manufacturing
processes or assessing any changes in formulation or treatment prior to use.
4.2 Assessment of fire hazard requires consideration of factors such as fuel contribution, intensity
of burning (rate of heat release) and products of combustion, as well as environmental factors such as
intensity of source, orientation of exposed material and ventilation conditions.
4.3 The horizontal burning characteristics, as measured by this test procedure, might be affected by
factors such as density, any anisotropy of the cellular material, its melting characteristics, its colour and
its thickness.
4.4 Certain materials might shrink from the applied flame without igniting. In this event, the test results
are not valid, and additional test specimens are required to obtain 10 valid test results. If this proves
impossible due to non-ignition of all the specimens, then this test is not suitable for these materials.
4.5 The horizontal burning characteristics of some cellular plastic materials might change with time,
and tests are therefore conducted before and after heat ageing.
2 © ISO 2020 – All rights reserved

5 Apparatus
5.1 A laboratory fume hood, having an inside volume of at least 0,5 m is used. The chamber shall
permit observation of tests in progress and shall provide a draught-free environment whilst allowing
normal thermal circulation of air past the test specimen during burning. The inside surfaces of
the chamber shall be of a dark colour. When a light meter, facing towards the rear of the chamber, is
positioned in place of the test specimen, the recorded light level shall be less than 20 lux.
For safety and convenience, this enclosure (which can be completely closed) shall be fitted with an
extraction device, such as an exhaust fan, to remove products of combustion that might be toxic. The
extraction device shall be turned off during the test and turned on again immediately after the test to
remove the fire effluents. A positive closing damper might be needed.
NOTE The amount of oxygen available to support combustion is naturally important for the conduct of these
flame tests. For tests conducted by this method when burning times are protracted, chamber sizes greater than
0,5 m might be needed to provide reproducible results.
5.2 P/PF2 laboratory burner, as specified in ISO 10093. The burner shall be the diffusion flame
burner specified in ISO 10093:2020, 11.3, having a barrel length of (100 ± 10) mm and an internal
diameter of (9,5 ± 0,3) mm. The barrel shall not be equipped with an end attachment, such as a stabilizer.
5.3 The burner shall be fitted with a burner wing top, having an opening of internal length (48 ± 1) mm
and internal width (1,3 ± 0,05) mm (see Figure 1).
To ensure the wing top opening is uniform in width, one option is to slide a (1,3 ± 0,05) mm steel wire
or spacer along its length.
5.4 The support gauze shall be a wire cloth of plain weave, approximately 215 mm long by 75 mm
wide, as shown in Figure 2. It shall consist of (6,4 ± 0,5) mm mesh gauze constructed of (0,9 ± 0,1) mm
diameter stainless steel, plain or low carbon steel wire. The cloth-mesh and wire diameter shall be
determined as described in the Standard Specification for Industrial Woven Wire Cloth, ASTM E2016.
5.5 The gauge-support holder shall consist of two laboratory ring stands with clamps adjustable to
the desired angles and heights. The gauze-support holder shall be constructed from aluminium or steel
and shall satisfy the following conditions:
— the long axis of the gauze shall be maintained to within 1° of the horizontal;
— the nearest end of the specimen shall be (13 ± 1) mm above the burner wing top (see Figure 2);
— the space both above and below the specimen shall not be obstructed;
— a means shall be provided for positioning the burner in the correct location relative to the specimen,
preferably with a sliding mechanism and a stop to allow fast movement of the burner flame towards
and away from the specimen;
— the gauze shall be equidistant from the front and back, and from both sides, of the test chamber, and
shall be (175 ± 25) mm above the cotton indicator base-board (see Figure 2).
5.6 There shall be two timing devices, each of which reads to within 1 s or less.
5.7 A measuring scale graduated in millimetres, shall be used to measure the length, width and
thickness of the test specimen.
5.8 The gas supply shall consist of technical-grade methane gas with
...