Fire extinguishing media — Foam concentrates — Part 1: Specification for low-expansion foam concentrates for top application to water-immiscible liquids

This document specifies the essential properties and performance of liquid foam concentrates used to make low-expansion foams for the control, the extinction and the inhibition of reignition of fires of water-immiscible liquids. Minimum performance on certain test fires is specified. These foams are suitable for top application to fires of water-immiscible liquids. The foams that conform with ISO 7203-3 are also suitable for top application to fires of water-miscible liquids. The foam concentrates can be suitable for use in non-aspirating sprayers or for subsurface application to liquid fires, but the requirements specific to those applications are outside the scope of this document.

Agents extincteurs — Émulseurs — Partie 1: Spécifications pour les émulseurs bas foisonnement destinés à une application par le haut sur les liquides non miscibles à l'eau

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Publication Date
30-Jun-2019
Current Stage
6060 - International Standard published
Due Date
11-Mar-2019
Completion Date
01-Jul-2019
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ISO 7203-1:2019(E)
ISO/PRF 7203-1:2019(E)
ISO TC 21/SC 6
Secretariat: SAC
Fire extinguishing media — Foam concentrates —
Part 1:
Specification for low-expansion foam concentrates for top application to water-immiscible
liquids
Agents extincteurs — Émulseurs —
Partie 1: Spécifications pour les émulseurs bas foisonnement destinés à une application par le haut sur les
liquides non miscibles à l'eau
DIS stage
Warning for WDs and CDs
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.
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 supporting documentation.
To help you, this guide on writing standards was produced by the ISO/TMB and is available at
https://www.iso.org/iso/how-to-write-standards.pdf
A model manuscript of a draft International Standard (known as “The Rice Model”) is available at
https://www.iso.org/iso/model_document-rice_model.pdf
© ISO 2019 – All rights reserved i

---------------------- Page: 1 ----------------------
ISO 7203-1:2019(E)
Contents Page
Foreword . v
Introduction. vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Grades and uses of foam concentrates . 4
5 Tolerance of foam concentrates to freezing and thawing . 4
6 Sediment in foam concentrates . 4
7 Determination of viscosity . 4
8 pH of foam concentrates . 5
9 Surface tension of the foam solution . 5
10 Interfacial tension between the foam solution and cyclohexane . 5
11 Spreading coefficient of the foam solution on cyclohexane . 6
12 Expansion and drainage of foam . 6
13 Test fire performance . 6
14 Marking, packaging and specification sheet . 7
Annex A (normative) Preliminary sampling and conditioning of the foam concentrate . 9
A.1 Preliminary sampling . 9
A.2 Conditioning of foam concentrate . 9
A.3 Subsequent testing . 9
Annex B (normative) Determination of tolerance to freezing and thawing . 10
B.1 Apparatus . 10
B.2 Procedure . 10
Annex C (normative) Determination of volume percentage of sediment . 12
C.1 Sampling . 12
C.2 Apparatus . 12
C.3 Procedure . 12
Annex D (normative) Determination of viscosity for pseudo-plastic foam concentrates . 13
D.1 General . 13
D.2 Viscosity determination . 13
D.2.1 Apparatus . 13
D.2.2 Test temperatures . 13
D.2.3 Viscosity measurement . 13
D.2.4 Results . 14
Annex E (normative) Determination of surface tension, interfacial tension and spreading
coefficient . 15
ii © ISO 2019 – All rights reserved

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ISO 7203-1:2019(E)
E.1 Reagents and materials . 15
E.2 Procedure for surface tension . 15
E.3 Procedure for interfacial tension . 15
E.4 Spreading coefficient . 15
Annex F (normative) Determination of expansion and drainage time . 16
F.1 Apparatus . 16
F.2 Temperature conditions . 16
F.3 Procedure . 16
Annex G (normative) Determination of test fire performance . 22
G.1 General . 22
G.2 General conditions . 22
G.2.1 Test series and criteria for success . 22
G.2.1.1 Foam concentrates not compatible with sea water . 22
G.2.1.2 Foam concentrates compatible with sea water . 22
G.2.1.3 Decision tree fire test protocol . 22
G.2.2 Temperature and wind speed . 23
G.2.3 Records . 23
G.2.4 Foam solution . 24
G.2.5 Fuel . 24
G.3 Forceful application fire test . 24
G.3.1 Apparatus . 24
G.3.2 Procedure . 24
G.4 Gentle application fire test . 25
G.4.1 Apparatus . 25
G.4.2 Test procedure . 26
G.5 Synthetic sea water . 27
Annex H (informative) Description of a radiation measurement method . 28
H.1 Evaluation . 28
H.2 General arrangement of test . 28
H.3 Technical data for radiometers . 28
H.4 Procedure . 29
Annex I (informative) Compatibility . 32
I.1 Compatibility between foam concentrates and fire extinguishing powders . 32
I.2 Compatibility between foam concentrates . 32
Annex J (informative) Small-scale fire test . 33
J.1 General . 33
J.2 Apparatus . 33
J.3 Test procedure . 33
© ISO 2019 – All rights reserved iii

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ISO 7203-1:2019(E)
J.3.1 Test conditions . 34
J.3.2 Set-up . 34
J.3.3 Fire test . 34
Bibliography . 42
iv © ISO 2019 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 7203-1:2019(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 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 on 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 the following URL:
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 21, Equipment for fire protection and fire
fighting, Subcommittee SC 6, Foam and powder media and firefighting systems using foam and powder.
This third edition cancels and replaces the second edition (ISO 7203-1:2011), which has been technically
revised.
The main changes compared to the previous edition are:
— addition of Part 4 containing specifications for Class A foam concentrates;
— extension of Clause 2;
— modification of Clause 12 to run two tests instead of one and take the average of both values instead
of having just one datum;
— correction of figures;
— extension of Annex G by a scheme of a decision tree, and modification of the acceptable temperature
range for testing fire performance;
— removal of Annex J: “Typical anticipated performance for various types of foam concentrate”.
A list of all parts in the ISO 7203 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.
© ISO 2019 – All rights reserved v

---------------------- Page: 5 ----------------------
ISO 7203-1:2019(E)
Introduction
Firefighting foams are widely used to control and extinguish fires of Class B (flammable liquids) and/or
Class A fuels (solid materials, usually of an organic nature) and for inhibiting reignition.
Foams can be used in combination with other extinguishing media, in particular halons, carbon dioxide
and powders which are the subject of other International Standards, including, ISO 6183, ISO 7201-1,
ISO 7201-2 and ISO 7202. A specification for foam systems can be found in ISO 7076.
Attention is drawn to Annex I, which deals with the compatibility of foam concentrates, and the
compatibility of foams and powders.
vi © ISO 2019 – All rights reserved

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INTERNATIONAL STANDARD ISO 7203-1:2019(E)

Fire extinguishing media — Foam concentrates — Part 1:
Specification for low-expansion foam concentrates for top
application to water-immiscible liquids
1 Scope
This document specifies the essential properties and performance of liquid foam concentrates used to
make low-expansion foams for the control, the extinction and the inhibition of reignition of fires of water-
immiscible liquids. Minimum performance on certain test fires is specified.
These foams are suitable for top application to fires of water-immiscible liquids. The foams that conform
with ISO 7203-3 are also suitable for top application to fires of water-miscible liquids.
The foam concentrates can be suitable for use in non-aspirating sprayers or for subsurface application to
liquid fires, but the requirements specific to those applications are outside 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 304, Surface active agents — Determination of surface tension by drawing up liquid films
ISO 3104, Petroleum products — Transparent and opaque liquids — Determination of kinematic viscosity
and calculation of dynamic viscosity
ISO 3219, Plastics — Polymers/resins in the liquid state or as emulsions or dispersions — Determination of
viscosity using a rotational viscometer with defined shear rate
ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 3506-1, Mechanical properties of corrosion-resistant stainless steel fasteners — Part 1: Bolts, screws
and studs
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
ISO 3734, Petroleum products — Determination of water and sediment in residual fuel oils — Centrifuge
method
ISO 7203-2, Fire extinguishing media — Foam concentrates — Part 2: Specification for medium- and high-
expansion foam concentrates for top application to water-immiscible liquids
ISO 7203-3, Fire extinguishing media — Foam concentrates — Part 3: Specification for low-expansion foam
concentrates for top application to water-miscible liquids
BS 5117-1.3:1985, Testing corrosion inhibiting, engine coolant concentrate (“antifreeze”). Methods of test
for determination of physical and chemical properties. Determination of freezing point
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
© ISO 2019 – All rights reserved 1

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ISO 7203-1:2019(E)
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
characteristic value
value declared by the foam concentrate supplier for the chemical and physical properties and the
performances of the foam, foam solution, and foam concentrate
3.2
25 % drainage time
time for 25 % of the liquid content of a foam to drain out
3.3
expansion
ratio of the volume of foam to the volume of the foam solution from which it was made
3.4
low-expansion
expansion (3.3) in the range 1 to 20, as applied to foam and to associated equipment, systems and
concentrates
3.5
medium-expansion
expansion (3.3) in the range 21 to 200, as applied to foam and to associated equipment, systems and
concentrates
3.6
high-expansion
expansion (3.3) greater than 200, as applied to foam and to associated equipment, systems and
concentrates
3.7
foam
aggregate of air-filled bubbles formed from an aqueous solution of a suitable foam
concentrate
3.8
concentrate
liquid that, when mixed with water in the appropriate concentration, gives a foam solution
3.9
protein foam concentrate
P
foam concentrate (3.8) derived from hydrolysed protein materials
3.10
fluoroprotein foam concentrate
FP
protein foam concentrate (3.8) with added fluorinated surface-active agents
3.11
synthetic foam concentrate
S
2 © ISO 2019 – All rights reserved

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ISO 7203-1:2019(E)
foam concentrate (3.8) based on a mixture of hydrocarbon surface-active agents and which can contain
fluorocarbons with additional stabilizers
3.12
alcohol-resistant foam concentrate
AR
foam concentrate (3.8) resistant to breakdown when applied to the surface of alcohol or other water-
miscible solvents
3.13
aqueous film-forming foam concentrate
AFFF
foam concentrate (3.8) based on a mixture of hydrocarbon and fluorinated surface-active agents with the
ability to form an aqueous film on the surface of some hydrocarbons
3.14
film-forming fluoroprotein foam concentrate
FFFP
fluoroprotein foam concentrate (3.8) that has the ability to form an aqueous film on the surface of some
hydrocarbons
3.15
foam solution
solution of foam concentrate (3.8) and water
3.16
forceful application
application of foam such that it falls directly onto the surface of a liquid fuel
3.17
gentle application
application of foam indirectly to the surface of a liquid fuel via a backboard, tank wall or other surface
3.18
sediment
insoluble particles in the foam concentrate
3.19
spreading coefficient
value calculated from the measured surface and interfacial tensions to indicate the ability of one liquid to
spontaneously spread across the surface of another
3.20
temperature for use
maximum and minimum temperatures claimed by the manufacturer between which the foam
concentrate is ready for use
3.21
fluorine-free foam concentrate
F3
foam concentrate (3.8) which does not form an aqueous film on hydrocarbon fuels, but which targets
Class B performance at forceful application and which does not contain any fluorochemicals
3.22
Class A foam concentrate
foam concentrate (3.8) for use on Class A fires (3.23)
© ISO 2019 – All rights reserved 3

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ISO 7203-1:2019(E)
3.23
Class A fire
fire involving solid materials, usually of an organic nature, in which combustion normally takes place with
the formation of glowing embers
Note 1 to entry: Adapted from ISO 3941:2007, Clause 2.
Note 2 to entry: Class A fires involve solid materials, usually of an organic nature (such as vegetation, wood, cloth
and paper), rubber, and some plastics, in which combustion can occur at or below the surface of the material, with
or without the formation of glowing embers.
4 Grades and uses of foam concentrates
4.1 Grades
According to its test fire performance (see Clause 13), a foam concentrate shall be graded
— as Class I, II or III for extinguishing performance, and
— as Level A, B, C or D for burn-back resistance.
4.2 Use with sea water
If a foam concentrate is marked as suitable for use with sea water, the recommended concentrations for
use with fresh water and for use with sea water shall be identical.
5 Tolerance of foam concentrates to freezing and thawing
A foam concentrate that the supplier claims not to be adversely affected by freezing and thawing shall
show no visual signs of either stratification or non-homogeneity before and after temperature
conditioning in accordance with A.2, when tested in accordance with Annex B.
Foam concentrates complying with this clause shall be tested for compliance with the appropriate
requirements given in other clauses of this document after freezing and thawing in accordance with A.2.1.
6 Sediment in foam concentrates
6.1 Sediment before ageing
Any sediment in the concentrate sampled in accordance with A.1 shall be dispersible through a 180 µm
sieve, and the volume percentage of sediment shall be not more than 0,25 % when tested in accordance
with Annex C.
6.2 Sediment after ageing
Any sediment in the concentrate aged in accordance with C.1 shall be dispersible through a 180 µm sieve,
and the volume percentage of sediment shall be not more than 1,0 % when tested in accordance with
Annex C.
7 Determination of viscosity
7.1 Newtonian foam concentrates
The viscosity of the foam concentrate at the lowest temperature for use claimed by the manufacturer
2 −1
shall be determined in accordance with ISO 3104. If the viscosity is greater than 200 mm s , the
container shall be marked as follows: “This concentrate can require special proportioning equipment”.
4 © ISO 2019 – All rights reserved

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ISO 7203-1:2019(E)
7.2 Pseudo-plastic foam concentrates
The viscosity of the foam concentrate shall be determined in accordance with Annex D. If the viscosity at
the lowest temperature for use is greater than or equal to 120 mPa*s at 375/s, the container shall be
marked as follows: “This concentrate can require special proportioning equipment”.
NOTE Pseudo-plastic foam concentrates are a particular class of non-Newtonian foam concentrates and have
a viscosity that decreases with increasing shear rate at constant temperature.
8 pH of foam concentrates
8.1 pH limits
The pH of the foam concentrate, before and after temperature conditioning in accordance with A.2, shall
be not less than 6,0 and not more than 8,5 at (20 ± 2) °C.
8.2 Sensitivity to temperature
The difference in pH between before and after temperature conditioning shall not be greater than 1,0 pH
units.
9 Surface tension of the foam solution
9.1 Before temperature conditioning
The surface tension of the foam solution prepared from the concentrate, before temperature conditioning
in accordance with A.2, at the supplier's recommended concentration, shall be within ±10 % of the
characteristic value when determined in accordance with E.2.
9.2 Temperature sensitivity
The surface tension of the foam solution prepared from the concentrate, after temperature conditioning
in accordance with A.2, at the supplier's recommended concentration, shall be determined in accordance
with E.2.
The value obtained after temperature conditioning shall not be less than 0,95 times, or more than
1,05 times, the value obtained before temperature conditioning.
10 Interfacial tension between the foam solution and cyclohexane
10.1 General
Interfacial tension shall only be tested on foam agents which are declared by the manufacturer to be
aqueous film-forming.
10.2 Before temperature conditioning
Before temperature conditioning in accordance with A.2, the difference between a) the interfacial tension
between the foam solution prepared from the foam concentrate and cyclohexane (when determined in
accordance with E.3) and b) the characteristic value for interfacial tension shall not exceed 1,0 mN/m or
10 % of the characteristic value, whichever is greater.
10.3 Temperature sensitivity
After temperature conditioning in accordance with A.2, the interfacial tension between the foam solution
prepared from the foam concentrate and cyclohexane shall be determined in accordance with E.3.
The two values obtained before and after temperature conditioning shall not differ by more than
0,5 mN/m.
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ISO 7203-1:2019(E)
11 Spreading coefficient of the foam solution on cyclohexane
The spreading coefficient shall only be tested on foam agents which are declared by the manufacturer to
be aqueous film-forming.
Before and after temperature conditioning in accordance with A.2, the spreading coefficient of the foam
solution prepared from a concentrate claimed by the supplier to be film-forming shall be positive when
calculated in accordance with E.4.
NOTE Foam concentrates conforming with this clause are more likely to be of type AFFF or FFFP than of
type FP, P, F3 or S.
12 Expansion and drainage of foam
12.1 General
Either of the following tests shall be conducted twice with potable water and if appropriate twice with
synthetic sea water, and the average of both series shall be recorded.
12.2 Expansion limits
The foam produced from the foam concentrate, before and after temperature conditioning in accordance
w
...

INTERNATIONAL ISO
STANDARD 7203-1
Third edition
2019-07
Fire extinguishing media — Foam
concentrates —
Part 1:
Specification for low-expansion foam
concentrates for top application to
water-immiscible liquids
Agents extincteurs — Émulseurs —
Partie 1: Spécifications pour les émulseurs bas foisonnement destinés
à une application par le haut sur les liquides non miscibles à l'eau
Reference number
ISO 7203-1:2019(E)
©
ISO 2019

---------------------- Page: 1 ----------------------
ISO 7203-1:2019(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 7203-1:2019(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Grades and uses of foam concentrates . 4
4.1 Grades . 4
4.2 Use with sea water . 4
5 Tolerance of foam concentrates to freezing and thawing . 4
6 Sediment in foam concentrates . 4
6.1 Sediment before ageing . 4
6.2 Sediment after ageing . 4
7 Determination of viscosity . 4
7.1 Newtonian foam concentrates . 4
7.2 Pseudo-plastic foam concentrates . 5
8 pH of foam concentrates . 5
8.1 pH limits. 5
8.2 Sensitivity to temperature . 5
9 Surface tension of the foam solution . 5
9.1 Before temperature conditioning . 5
9.2 Temperature sensitivity . 5
10 Interfacial tension between the foam solution and cyclohexane. 5
10.1 General . 5
10.2 Before temperature conditioning . 5
10.3 Temperature sensitivity . 6
11 Spreading coefficient of the foam solution on cyclohexane . 6
12 Expansion and drainage of foam. 6
12.1 General . 6
12.2 Expansion limits . 6
12.3 Drainage limits . 6
13 Test fire performance . 6
14 Marking, packaging and specification sheet . 7
14.1 Marking . 7
14.2 Packaging . 8
14.3 Specification sheet . 8
Annex A (normative) Preliminary sampling and conditioning of the foam concentrate .9
Annex B (normative) Determination of tolerance to freezing and thawing .10
Annex C (normative) Determination of volume percentage of sediment .12
Annex D (normative) Determination of viscosity for pseudo-plastic foam concentrates .13
Annex E (normative) Determination of surface tension, interfacial tension and spreading
coefficient .15
Annex F (normative) Determination of expansion and drainage time .16
Annex G (normative) Determination of test fire performance .22
Annex H (informative) Description of a radiation measurement method .28
© ISO 2019 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 7203-1:2019(E)

Annex I (informative) Compatibility .32
Annex J (informative) Small-scale fire test .33
Bibliography .42
iv © ISO 2019 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 7203-1:2019(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 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 on 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 the following URL:
www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 21, Equipment for fire protection and fire
fighting, Subcommittee SC 6, Foam and powder media and firefighting systems using foam and powder.
This third edition cancels and replaces the second edition (ISO 7203-1:2011), which has been technically
revised.
The main changes compared to the previous edition are:
— addition of Part 4 containing specifications for Class A foam concentrates;
— extension of Clause 2;
— modification of Clause 12 to run two tests instead of one and take the average of both values instead
of having just one datum;
— correction of figures;
— extension of Annex G by a scheme of a decision tree, and modification of the acceptable temperature
range for testing fire performance;
— removal of Annex J: “Typical anticipated performance for various types of foam concentrate”.
A list of all parts in the ISO 7203 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.
© ISO 2019 – All rights reserved v

---------------------- Page: 5 ----------------------
ISO 7203-1:2019(E)

Introduction
Firefighting foams are widely used to control and extinguish fires of Class B (flammable liquids) and/or
Class A fuels (solid materials, usually of an organic nature) and for inhibiting reignition.
Foams can be used in combination with other extinguishing media, in particular halons, carbon dioxide
and powders which are the subject of other International Standards, including, ISO 6183, ISO 7201-1,
ISO 7201-2 and ISO 7202. A specification for foam systems can be found in ISO 7076.
Attention is drawn to Annex I, which deals with the compatibility of foam concentrates, and the
compatibility of foams and powders.
vi © ISO 2019 – All rights reserved

---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 7203-1:2019(E)
Fire extinguishing media — Foam concentrates —
Part 1:
Specification for low-expansion foam concentrates for top
application to water-immiscible liquids
1 Scope
This document specifies the essential properties and performance of liquid foam concentrates used
to make low-expansion foams for the control, the extinction and the inhibition of reignition of fires of
water-immiscible liquids. Minimum performance on certain test fires is specified.
These foams are suitable for top application to fires of water-immiscible liquids. The foams that conform
with ISO 7203-3 are also suitable for top application to fires of water-miscible liquids.
The foam concentrates can be suitable for use in non-aspirating sprayers or for subsurface application to
liquid fires, but the requirements specific to those applications are outside 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 304, Surface active agents — Determination of surface tension by drawing up liquid films
ISO 3104, Petroleum products — Transparent and opaque liquids — Determination of kinematic viscosity
and calculation of dynamic viscosity
ISO 3219, Plastics — Polymers/resins in the liquid state or as emulsions or dispersions — Determination of
viscosity using a rotational viscometer with defined shear rate
ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 3506-1, Mechanical properties of corrosion-resistant stainless steel fasteners — Part 1: Bolts, screws
and studs
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
ISO 3734, Petroleum products — Determination of water and sediment in residual fuel oils —
Centrifuge method
ISO 7203-2, Fire extinguishing media — Foam concentrates — Part 2: Specification for medium- and high-
expansion foam concentrates for top application to water-immiscible liquids
ISO 7203-3, Fire extinguishing media — Foam concentrates — Part 3: Specification for low-expansion foam
concentrates for top application to water-miscible liquids
BS 5117-1.3:1985, Testing corrosion inhibiting, engine coolant concentrate (“antifreeze”). Methods of test
for determination of physical and chemical properties. Determination of freezing point
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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ISO 7203-1:2019(E)

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
characteristic value
value declared by the foam concentrate supplier for the chemical and physical properties and the
performances of the foam, foam solution, and foam concentrate
3.2
25 % drainage time
time for 25 % of the liquid content of a foam to drain out
3.3
expansion
ratio of the volume of foam to the volume of the foam solution from which it was made
3.4
low-expansion
expansion (3.3) in the range 1 to 20, as applied to foam and to associated equipment, systems and
concentrates
3.5
medium-expansion
expansion (3.3) in the range 21 to 200, as applied to foam and to associated equipment, systems and
concentrates
3.6
high-expansion
expansion (3.3) greater than 200, as applied to foam and to associated equipment, systems and
concentrates
3.7
foam
aggregate of air-filled bubbles formed from an aqueous solution of a suitable foam
concentrate
3.8
concentrate
liquid that, when mixed with water in the appropriate concentration, gives a foam solution
3.9
protein foam concentrate
P
foam concentrate (3.8) derived from hydrolysed protein materials
3.10
fluoroprotein foam concentrate
FP
protein foam concentrate (3.8) with added fluorinated surface-active agents
3.11
synthetic foam concentrate
S
foam concentrate (3.8) based on a mixture of hydrocarbon surface-active agents and which can contain
fluorocarbons with additional stabilizers
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ISO 7203-1:2019(E)

3.12
alcohol-resistant foam concentrate
AR
foam concentrate (3.8) resistant to breakdown when applied to the surface of alcohol or other water-
miscible solvents
3.13
aqueous film-forming foam concentrate
AFFF
foam concentrate (3.8) based on a mixture of hydrocarbon and fluorinated surface-active agents with
the ability to form an aqueous film on the surface of some hydrocarbons
3.14
film-forming fluoroprotein foam concentrate
FFFP
fluoroprotein foam concentrate (3.8) that has the ability to form an aqueous film on the surface of some
hydrocarbons
3.15
foam solution
solution of foam concentrate (3.8) and water
3.16
forceful application
application of foam such that it falls directly onto the surface of a liquid fuel
3.17
gentle application
application of foam indirectly to the surface of a liquid fuel via a backboard, tank wall or other surface
3.18
sediment
insoluble particles in the foam concentrate
3.19
spreading coefficient
value calculated from the measured surface and interfacial tensions to indicate the ability of one liquid
to spontaneously spread across the surface of another
3.20
temperature for use
maximum and minimum temperatures claimed by the manufacturer between which the foam
concentrate is ready for use
3.21
fluorine-free foam concentrate
F3
foam concentrate (3.8) which does not form an aqueous film on hydrocarbon fuels, but which targets
Class B performance at forceful application and which does not contain any fluorochemicals
3.22
Class A foam concentrate
foam concentrate (3.8) for use on Class A fires (3.23)
3.23
Class A fire
fire involving solid materials, usually of an organic nature, in which combustion normally takes place
with the formation of glowing embers
Note 1 to entry: Adapted from ISO 3941:2007, Clause 2.
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ISO 7203-1:2019(E)

Note 2 to entry: Class A fires involve solid materials, usually of an organic nature (such as vegetation, wood, cloth
and paper), rubber, and some plastics, in which combustion can occur at or below the surface of the material,
with or without the formation of glowing embers.
4 Grades and uses of foam concentrates
4.1 Grades
According to its test fire performance (see Clause 13), a foam concentrate shall be graded
— as Class I, II or III for extinguishing performance, and
— as Level A, B, C or D for burn-back resistance.
4.2 Use with sea water
If a foam concentrate is marked as suitable for use with sea water, the recommended concentrations for
use with fresh water and for use with sea water shall be identical.
5 Tolerance of foam concentrates to freezing and thawing
A foam concentrate that the supplier claims not to be adversely affected by freezing and thawing
shall show no visual signs of either stratification or non-homogeneity before and after temperature
conditioning in accordance with A.2, when tested in accordance with Annex B.
Foam concentrates complying with this clause shall be tested for compliance with the appropriate
requirements given in other clauses of this document after freezing and thawing in accordance with A.2.1.
6 Sediment in foam concentrates
6.1 Sediment before ageing
Any sediment in the concentrate sampled in accordance with A.1 shall be dispersible through a 180 µm
sieve, and the volume percentage of sediment shall be not more than 0,25 % when tested in accordance
with Annex C.
6.2 Sediment after ageing
Any sediment in the concentrate aged in accordance with C.1 shall be dispersible through a 180 µm
sieve, and the volume percentage of sediment shall be not more than 1,0 % when tested in accordance
with Annex C.
7 Determination of viscosity
7.1 Newtonian foam concentrates
The viscosity of the foam concentrate at the lowest temperature for use claimed by the manufacturer
2 −1
shall be determined in accordance with ISO 3104. If the viscosity is greater than 200 mm s , the
container shall be marked as follows: “This concentrate can require special proportioning equipment”.
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ISO 7203-1:2019(E)

7.2 Pseudo-plastic foam concentrates
The viscosity of the foam concentrate shall be determined in accordance with Annex D. If the viscosity
at the lowest temperature for use is greater than or equal to 120 mPa*s at 375/s, the container shall be
marked as follows: “This concentrate can require special proportioning equipment”.
NOTE Pseudo-plastic foam concentrates are a particular class of non-Newtonian foam concentrates and
have a viscosity that decreases with increasing shear rate at constant temperature.
8 pH of foam concentrates
8.1 pH limits
The pH of the foam concentrate, before and after temperature conditioning in accordance with A.2,
shall be not less than 6,0 and not more than 8,5 at (20 ± 2) °C.
8.2 Sensitivity to temperature
The difference in pH between before and after temperature conditioning shall not be greater than
1,0 pH units.
9 Surface tension of the foam solution
9.1 Before temperature conditioning
The surface tension of the foam solution prepared from the concentrate, before temperature
conditioning in accordance with A.2, at the supplier's recommended concentration, shall be within
±10 % of the characteristic value when determined in accordance with E.2.
9.2 Temperature sensitivity
The surface tension of the foam solution prepared from the concentrate, after temperature conditioning
in accordance with A.2, at the supplier's recommended concentration, shall be determined in accordance
with E.2.
The value obtained after temperature conditioning shall not be less than 0,95 times, or more than
1,05 times, the value obtained before temperature conditioning.
10 Interfacial tension between the foam solution and cyclohexane
10.1 General
Interfacial tension shall only be tested on foam agents which are declared by the manufacturer to be
aqueous film-forming.
10.2 Before temperature conditioning
Before temperature conditioning in accordance with A.2, the difference between a) the interfacial
tension between the foam solution prepared from the foam concentrate and cyclohexane (when
determined in accordance with E.3) and b) the characteristic value for interfacial tension shall not
exceed 1,0 mN/m or 10 % of the characteristic value, whichever is greater.
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ISO 7203-1:2019(E)

10.3 Temperature sensitivity
After temperature conditioning in accordance with A.2, the interfacial tension between the foam solution
prepared from the foam concentrate and cyclohexane shall be determined in accordance with E.3.
The two values obtained before and after temperature conditioning shall not differ by more than
0,5 mN/m.
11 Spreading coefficient of the foam solution on cyclohexane
The spreading coefficient shall only be tested on foam agents which are declared by the manufacturer
to be aqueous film-forming.
Before and after temperature conditioning in accordance with A.2, the spreading coefficient of the foam
solution prepared from a concentrate claimed by the supplier to be film-forming shall be positive when
calculated in accordance with E.4.
NOTE Foam concentrates conforming with this clause are more likely to be of type AFFF or FFFP than of
type FP, P, F3 or S.
12 Expansion and drainage of foam
12.1 General
Either of the following tests shall be conducted twice with potable water and if appropriate twice with
synthetic sea water, and the average of both series shall be recorded.
12.2 Expansion limits
The foam produced from the foam concentrate, before and after temperature conditioning in accordance
with A.2, with potable water and, if appropriate, with the synthetic sea water according to G.2.4, shall
have an average expansion within either ±20 % of the characteristic value or ±1,0 of the characteristic
value, whichever is greater, when tested in accordance with Annex F.
12.3 Drainage limits
The foam produced from the foam concentrate, before and after temperature conditioning in accordance
with A.2, with potable water and, if appropriate, with the synthetic sea water according to G.2.4, shall
have a 25 % average drainage time within ±20 % of the characteristic value when tested in accordance
with Annex F.
13 Test fire performance
The foam produced from the foam concentrate with potable water and, if appropriate, with the
synthetic sea water according to G.2.4, shall have an extinguishing performance class and burn-back
resistance level as specified in Table 1 when tested in accordance with G.2 and G.3, G.2 and G.4, or G.2
and G.3 plus G.4, as appropriate.
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ISO 7203-1:2019(E)

Table 1 — Maximum extinction times and minimum burn-back times
Durations expressed in minutes
Gentle application test Forceful application test
(See G.4) (See G.3)
Extinguishing
Burn-back
performance
25 % burn-back 25 % burn-back
resistance level
Extinction time Extinction time
class
time not less time not less
not more than not more than
than than
A Not applicable 3 10
B 15 3
I
C Not applicable 10 3 Not applicable
D 5 3
A Not applicable 4 10
B 15 4
II
C Not applicable 10 4 Not applicable
D 5 4
B 5 15
III C 5 10 Not applicable
D 5 5
NOTE 1  There is no burn-back resistance Level A for Class III.
NOTE 2  Extinction time is the period from the start of foam application until the time when all flames are extinguished.
NOTE 3  25 % burn-back time is the period from the ignition of the burn-back pot fuel until 25 % of the tray is covered by
sustained flames or by “flare up” flames.
14 Marking, packaging and specification sheet
14.1 Marking
14.1.1 The following information shall be marked on the shipping container:
a) designation (identifying name) of the concentrate and the words “low-expansion foam concentrate”;
b) Class (I, II or III) and Level (A, B, C or D) of the foam concentrate and, if the concentrate complies
with Clause 11, the words “aqueous film-forming”;
c) recommended concentration for use (most commonly 1 %, 3 %, or 6 %);
d) any tendency of the foam concentrate to cause harmful physical effects, the methods required to
avoid them and the first aid treatment if they occur;
e) recommended storage temperature and temperature of use;
f) if the concentrate complies with Clause 5, it shall be marked with the words; “Not affected by
freezing and thawing”; or, if the foam concentrate does not comply with Clause 5, the words “Do not
freeze”;
g) nominal quantity in the container;
h) supplier's name and address;
i) batch number;
j) it shall be marked with the words “Not suitable for use with sea water” or “Suitable for use with sea
water”, as appropriate.
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ISO 7203-1:2019(E)

WARNING — It is extremely important that the foam concentrate, after dilution with water to
the recommended concentration, shall not, in normal usage, present a significant toxic hazard
to life in relation to the environment.
The recommended storage temperature and temperature of use are the same if the product
...

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