ISO 7203-2:2019
(Main)Fire extinguishing media — Foam concentrates — Part 2: Specification for medium- and high-expansion foam concentrates for top application to water-immiscible liquids
Fire extinguishing media — Foam concentrates — Part 2: Specification for medium- and high-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 medium- or high-expansion foams or both 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 liquid. Those foams that comply with ISO 7203-1 are also suitable for top application to fires of water-immiscible liquids.
Agents extincteurs — Émulseurs — Partie 2: Spécifications pour les émulseurs moyen et haut foisonnements destinés à une application par le haut sur les liquides non miscibles à l'eau
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© ISO 2019 – All rights reserved
ISO/PRF 7203-2:2019(E)
ISO TC 21/SC 6
Secretariat: SAC
Fire extinguishing media — Foam concentrates —
Part 2:
Specification for medium- and high-expansion foam concentrates for top application to water-
immiscible liquids
Agents extincteurs — Émulseurs —
Partie 2: Spécifications pour les émulseurs moyen et haut foisonnements destinés à une
application par le haut sur les liquides non miscibles à l'eau
DIS stage
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ISO 7203-2:2019(E)
© ISO 2019, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or
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Tel. + 41 22 749 01 11
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ii © ISO 2019 – All rights reserved
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ISO 7203-2:2019(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 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 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 7203-2:2011), which has been technically
revised.
The main changes compared to the previous edition are:
— addition of Clause 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
having just one datum;
— correction of several figures;
— the extension of Annex H by a scheme of a decision tree and the modification of the acceptable
temperature range for testing fire performance;
— removal of Annex “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.
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ISO 7203-2:2019(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 K, which deals with the compatibility of foam concentrates, and the
compatibility of foams and powders.
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ISO 7203-2:2019(E)
Fire extinguishing media — Foam concentrates —Part 2:
Specification for medium- and high-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 medium- or high-expansion foams or both 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 liquid. Those foams that comply
with ISO 7203-1 are also suitable for top application to fires of water-immiscible liquids.
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 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 7203-1, Fire extinguishing media — Foam concentrates — Part 1: Specification for low-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 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
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ISO 7203-2:2019(E)
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
3.12
alcohol-resistant foam concentrate
AR
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ISO 7203-2:2019(E)
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 is targeting
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
Class A fire
fire involving solid materials, usually of an organic nature, in which combustion normally takes place with
the formation of glowing embers
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ISO 7203-2:2019(E)
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 Classification and uses of foam concentrates
4.1 Classification
The foam concentrate shall be classified as medium- or high- expansion or both and shall comply with
the appropriate requirements.
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 sea water shall be identical.
5 Tolerance of the foam concentrate to freezing and thawing
Before and after temperature conditioning in accordance with A.2, the foam concentrate, if claimed by
the supplier not to be adversely affected by freezing and thawing, shall show no visual sign of
stratification and non-homogeneity, 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 the foam concentrate
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 “This concentrate can require special proportioning equipment”.
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 “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.
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ISO 7203-2:2019(E)
8 pH of the foam concentrate
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.
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.
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ISO 7203-2:2019(E)
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
12.1 Medium-expansion foam concentrates — 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 of H.2.4, shall have an
expansion of not less than 21 when tested in accordance with Annex F.
12.2 High-expansion foam concentrate — 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 of I.2.4, shall have an
expansion of not less than 201 when tested in accordance with Annex G.
13 Test fire performance
The foam produced from the foam concentrate with potable water, and if appropriate, with the synthetic
sea water according to H.2.4 and/or I.2.4, shall have an extinguishing performance class and burn-back
resistance level as specified in Table 1 when tested in accordance with Annex H or Annex I, or both, as
appropriate.
Table 1 — Test fire performance
Types of expansion foam Medium-expansion foam High-expansion foam
Extinction time, seconds Not more than 120 Not more than 150
1 % burn-back time,
Not less than 30 Not applicable
seconds
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, as appropriate, the words “medium” or “high”,
or “medium and high” and “expansion foam concentrate”;
b) 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 should occur;
e) recommended storage temperature and temperature of use;
f) if the concentrate complies with Clause 5, 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;
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ISO 7203-2:2019(E)
j) words “Not suitable for use with sea water” or “Suitable for use with sea water”, as appropriate.
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.
NOTE Recommended storage temperature and temperature of use are the same if the product is marked “do
not freeze”.
14.1.2 Markings on shipping containers shall be permanent and legible.
14.1.3 It is recommended that non-Newtonian concentrates be appropriately identified.
14.1.4 Foam concentrates complying with ISO 7203-1 shall also be marked “low-expansion”.
14.1.5 Foam concentrates in accordance with ISO 7203-3 shall also be marked “alcohol resistant”.
14.2 Packaging
The packaging of the foam concentrate shall ensure that the essential characteristics of the concentrate
are preserved when stored and handled in accordance with the supplier's recommendations.
14.3 Specification sheet
14.3.1 If requested by the user, the supplier shall provide a list of the characteristic values.
14.3.2 If the foam concentrate is Newtonian and the viscosity at the lowest temperature for use is more
2
than 200 mm /s when measured in accordance with ISO 3104, it shall be marked with the words “This
concentrate can require special proportioning equipment”.
14.3.3 If the foam concentrate is pseudo-plastic and the viscosity at the lowest temperature for use is
greater than or equal to 120 mPa⋅s at 375/s, it shall be marked “This concentrate can require special
proportioning equipment”.
14.3.4 It is recommended that non-Newtonian concentrates be appropriately identified.
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ISO 7203-2:2019(E)
Annex A
(normative)
Preliminary sampling and conditioning of the foam concentrate
A.1 Preliminary sampling
The sampling method shall ensure representative samples, whether taken from a bulk container or a
number of individual packages.
Store samples in fully closed containers.
NOTE Containers with a capacity of 20 l are suitable.
A.2 Conditioning of foam concentrate
A.2.1 If the supplier claims that the concentrate is not adversely affected by freezing and thawing,
condition the concentrate sample through four cycles of freezing and thawing, generally as described in
B.2, before conditioning in accordance with A.2.2. If the foam concentrate is adversely affected by freezing
and thawing, it shall be conditioned according to A.2.2 without prior freezing and thawing.
A.2.2 Condition the concentrate in the sealed container for 7 d at (60 ± 2) °C, followed by 1 d at
(20 ± 5) °C.
A.3 Subsequent testing
Test samples prepared in accordance with A.1, or A.1 and A.2 as appropriate. Shake the sample container
before sampling for further tests.
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ISO 7203-2:2019(E)
Annex B
(normative)
Determination of tolerance to freezing and thawing
B.1 Apparatus
The usual laboratory apparatus and, in particular, the following.
B.1.1 Freezing chamber, capable of achieving the temperatures required in B.2.
B.1.2 Polyethylene tube, approximately 10 mm in diameter, approximately 400 mm long and sealed
and weighted at one end, with suitable spacers attached.
Figure B.1 shows a typical form.
B.1.3 Measuring cylinder, glass, of 500 ml capacity, approximately 400 mm high and approximately
65 mm in diameter, with a stopper.
B.2 Procedure
Set the temperature of the freezing chamber (B.1.1) to at least 10 °C below the freezing point of the
sample, measured in accordance with BS 5117-1.3, excluding 5.2.
To prevent the glass measuring cylinder (B.1.3) from breaking due to expansion of the foam concentrate
on freezing, insert the tube (B.1.2) into the measuring cylinder with the sealed end downward, weighted
if necessary to avoid flotation, the spacers ensuring it remains approximately on the central axis of the
cylinder. Fill the cylinder and fit the stopper.
Place the cylinder in the freezing chamber, cool it and maintain at the required temperature for 24 h. At
the end of this period, thaw the sample for not less than 24 h and not more than 96 h in an ambient
temperature of (20 ± 5) °C.
Repeat three times to give four cycles of freezing and thawing before testing.
Examine the sample for stratification and non-homogeneity.
Nominal dimensions in millimetres
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ISO 7203-2:2019(E)
Key
1 spacers (e.g. plastic cable strap)
2 mass at sealed end
Figure B.1 — Typical form of polyethylene tube
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ISO 7203-2:2019(E)
Annex C
(normative)
Determination of volume percentage of sediment
C.1 Sampling
Use a sample prepared in accordance with A.1. Ensure that any sediment is dispersed by shaking the
sample container. Take two samples, testing one immediately and the other after ageing for (24 ± 2) h at
(60 ± 2) °C in a filled container without access to air.
C.2 Apparatus
The usual laboratory apparatus and, in particular, the following.
C.2.1 Centrifuge tubes, graduated.
Centrifuge tubes complying with ISO 3734 are suitable.
2
C.2.2 Centrifuge, operating at (6 000 ± 600) m/s .
A centrifuge complying with ISO 3734 is suitable.
C.2.3 Sieve, of nominal aperture size 180 µm, complying with ISO 3310-1.
C.2.4 Wash bottle, plastic.
C.3 Procedure
Centrifuge each sample of the concentrate for (10 ± 1) min. Determine the volume of the sediment and
record it as a percentage of volume of the centrifuged sample volume.
Wash the contents of the centrifuge tube (C.2.1) onto the sieve (C.2.3) and check whether the sediment
can or cannot be dispersed through the sieve by the jet from the plastic wash bottle (C.2.4).
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ISO 7203-2:2019(E)
Annex D
(normative)
Determination of viscosity for pseudo-plastic foam concentrates
D.1 General
This annex gives the procedure for determining the viscosity for pseudo-plastic foam concentrates. The
procedure is described in ISO 3219.
NOTE Pseudo-plastic foam concentrates are a particular class of non-Newtonian foam concentrate and have a
viscosity which decreases with increasing shear rate at constant temperature.
D.2 Viscosity determination
D.2.1 Apparatus
The usual laboratory apparatus and the following.
D.2.1.1 Rotational viscometer, in accordance with ISO 3219 with the following parameters:
— maximum shear stress of ≥75 Pa;
— maximum shear rate of ≥600/s.
The viscometer shall be fitted with a temperature control unit which can maintain the sample
temperature within ±1 °C of the required temperature.
D.2.2 Test temperatures
The viscosity of the foam concentrate shall be measured from 20 °C down to, and including, the lowest
temperature for use claimed by the manufacturer, in increments of 10 °C. Use a fresh sample for each
temperature.
D.2.3 Viscosity measurement
If the sample contains suspended air bubbles, the sample shall be centrifuged for 10 min using the
apparatus specified in C.2.1 and C.2.2 before the sample is placed in the apparatus.
The test should be performed according to the following test procedure:
a) Adjust the temperature control unit.
b) Set the gap.
c) Apply the sample.
d) Wait a minimum of 10 min (with no shear) to reach temperature equilibrium.
e) Pre-shear for 1 min at 600/s.
f) Wait 1 min without shearing.
g) Measure the shear stress for 10 s at each shear rate, starting at the lowest shear rate (preferably at
75/s).
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ISO 7203-2:2019(E)
h) Measure the shear stress at a minimum of eight different shear rates over the range (0/s to 600/s),
e.g. 75/s, 150/s, 225/s, 300/s, 375/s, 450/s, 525/s, 600/s. Calculate the apparent viscosity, v,
expressed in millipascal-seconds, as given in Formula (D.1)
s
1
v=1000
(D.1)
s
2
where
s is the shear stress, expressed in pascals;
1
s is the shear rate, expressed in reciprocal seconds.
2
D.2.4 Results
Report the results as a table including test temperature, expressed in degrees Celsius, the shear rate,
expressed in reciprocal seconds, the shear stress, expressed in reciprocal seconds, and the apparent
viscosity, expressed in millipascal-seconds.
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ISO 7203-2:2019(E)
Annex E
(normative)
Determination of surface tension, interfacial tension and spreading
coefficient
E.1 Reagents and materials
E.1.1 Solution of foam concentrate, at the recommended concentration for use in freshly made
analytical water complying with grade 3 of ISO 3696:1987 and with surface tension not less than
70 mN/m.
NOTE The solution can be made up in a 100 ml volumetric flask, using a pipette to measure the foam
concentrate.
E.1.2 Cyclohexane, of purity not less than 99 %, for interfacial tension and spreading coefficient only.
E.2 Procedure for surface tension
Determine the surface tension of the solution (E.1.1) at a temperature of (20 ± 1) °C, using the ring
method in accordance with ISO 304.
E.3 Procedure for interfacial tension
After measuring the surface tension in accordance with E.2, introduce a layer of cyclohexane (E.1.2) at
(20 ± 1) °C onto the foam solution (E.1.1), being careful to avoid contact between the ring and the
cyclohexane. Wait (6 ± 1) min and then measure the interfacial tension.
E.4 Spreading coefficient
Calculate the spreading coefficient, S, expressed in millinewtons per metre (mN/m), between the solution
(E.1.1) and cyclohexane (E.1.2) from Formula (E.1):
S=Y −Y −Y (E.1)
c f i
where
Y is the surface tension of the cyclohexane, expressed in millinewtons per metre;
c
Y is the surface tension of the foam solution, expressed in millinewtons per metre;
f
Y is the interfacial tension between the foam solution and cyclohexane, expressed in millinewton
...
INTERNATIONAL ISO
STANDARD 7203-2
Third edition
2019-07
Fire extinguishing media — Foam
concentrates —
Part 2:
Specification for medium- and high-
expansion foam concentrates for top
application to water-immiscible liquids
Agents extincteurs — Émulseurs —
Partie 2: Spécifications pour les émulseurs moyen et haut
foisonnements destinés à une application par le haut sur les liquides
non miscibles à l'eau
Reference number
ISO 7203-2:2019(E)
©
ISO 2019
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ISO 7203-2:2019(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
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on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
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ISO 7203-2:2019(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification and uses of foam concentrates . 4
4.1 Classification . 4
4.2 Use with sea water . 4
5 Tolerance of the foam concentrate to freezing and thawing . 4
6 Sediment in the foam concentrate . 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 . 4
8 pH of the foam concentrate . 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 . 5
11 Spreading coefficient of the foam solution on cyclohexane . 5
12 Expansion . 6
12.1 Medium-expansion foam concentrates — Limits . 6
12.2 High-expansion foam concentrate — Limits . 6
13 Test fire performance . 6
14 Marking, packaging and specification sheet . 6
14.1 Marking . 6
14.2 Packaging . 7
14.3 Specification sheet . 7
Annex A (normative) Preliminary sampling and conditioning of the foam concentrate .8
Annex B (normative) Determination of tolerance to freezing and thawing .9
Annex C (normative) Determination of volume percentage of sediment .11
Annex D (normative) Determination of viscosity for pseudo-plastic foam concentrates .12
Annex E (normative) Determination of surface tension, interfacial tension and spreading
coefficient .14
Annex F (normative) Determination of expansion and drainage time for medium-
expansion foam concentrates .15
Annex G (normative) Determination of expansion anddrainage time for high-expansion
foam concentrates .20
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ISO 7203-2:2019(E)
Annex H (normative) Determination of test fire performance formedium-expansion foam
concentrates .26
Annex I (normative) Determination of test fire performance forhigh-expansion foam
concentrates .31
Annex J (informative) Determination of radiation measurement method .36
Annex K (informative) Compatibility .40
Bibliography .41
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ISO 7203-2:2019(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 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 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 7203-2:2011), which has been technically
revised.
The main changes compared to the previous edition are:
— addition of Clause 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
having just one datum;
— correction of several figures;
— the extension of Annex H by a scheme of a decision tree and the modification of the acceptable
temperature range for testing fire performance;
— removal of Annex “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.
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ISO 7203-2:2019(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 K, which deals with the compatibility of foam concentrates, and the
compatibility of foams and powders.
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INTERNATIONAL STANDARD ISO 7203-2:2019(E)
Fire extinguishing media — Foam concentrates —
Part 2:
Specification for medium- and high-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 medium- or high-expansion foams or both 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 liquid. Those foams that
comply with ISO 7203-1 are also suitable for top application to fires of water-immiscible liquids.
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 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 7203-1, Fire extinguishing media — Foam concentrates — Part 1: Specification for low-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 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/
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ISO 7203-2:2019(E)
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
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
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ISO 7203-2:2019(E)
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 is
targeting 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
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.
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ISO 7203-2:2019(E)
4 Classification and uses of foam concentrates
4.1 Classification
The foam concentrate shall be classified as medium- or high- expansion or both and shall comply with
the appropriate requirements.
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 sea water shall be identical.
5 Tolerance of the foam concentrate to freezing and thawing
Before and after temperature conditioning in accordance with A.2, the foam concentrate, if claimed
by the supplier not to be adversely affected by freezing and thawing, shall show no visual sign of
stratification and non-homogeneity, 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 the foam concentrate
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 “This concentrate can require special proportioning equipment”.
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 “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.
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ISO 7203-2:2019(E)
8 pH of the foam concentrate
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.
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.
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ISO 7203-2:2019(E)
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
12.1 Medium-expansion foam concentrates — 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 of H.2.4, shall have an
expansion of not less than 21 when tested in accordance with Annex F.
12.2 High-expansion foam concentrate — 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 of I.2.4, shall have an
expansion of not less than 201 when tested in accordance with Annex G.
13 Test fire performance
The foam produced from the foam concentrate with potable water, and if appropriate, with the synthetic
sea water according to H.2.4 and/or I.2.4, shall have an extinguishing performance class and burn-back
resistance level as specified in Table 1 when tested in accordance with Annex H or Annex I, or both, as
appropriate.
Table 1 — Test fire performance
Types of expansion foam Medium-expansion foam High-expansion foam
Extinction time, seconds Not more than 120 Not more than 150
1 % burn-back time, seconds Not less than 30 Not applicable
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, as appropriate, the words “medium” or
“high”, or “medium and high” and “expansion foam concentrate”;
b) 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 should occur;
e) recommended storage temperature and temperature of use;
f) if the concentrate complies with Clause 5, 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;
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ISO 7203-2:2019(E)
h) supplier's name and address;
i) batch number;
j) words “Not suitable for use with sea water” or “Suitable for use with sea water”, as appropriate.
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.
NOTE Recommended storage temperature and temperature of use are the same if the product is marked “do
not freeze”.
14.1.2 Markings on shipping containers shall be permanent and legible.
14.1.3 It is recommended that non-Newtonian concentrates be appropriately identified.
14.1.4 Foam concentrates complying with ISO 7203-1 shall also be marked “low-expansion”.
14.1.5 Foam concentrates in accordance with ISO 7203-3 shall also be marked “alcohol resistant”.
14.2 Packaging
The packaging of the foam concentrate shall ensure that the essential characteristics of the concentrate
are preserved when stored and handled in accordance with the supplier's recommendations.
14.3 Specification sheet
14.3.1 If requested by the user, the supplier shall provide a list of the characteristic values.
14.3.2 If the foam concentrate is Newtonian and the viscosity at the lowest temperature for use is more
2
than 200 mm /s when measured in accordance with ISO 3104, it shall be marked with the words “This
concentrate can require special proportioning equipment”.
14.3.3 If the foam concentrate is pseudo-plastic and the viscosity at the lowest temperature for use is
greater than or equal to 120 mPa⋅s at 375/s, it shall be marked “This concentrate can require special
proportioning equ
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