Methods for sampling and analysis of fire effluents

This International Standard presents a range of sampling and chemical analytical methods suitable for
the analysis of individual chemical species in fire atmospheres. The procedures relate to the analysis of
samples extracted from an apparatus or effluent flow from a fire test rig or physical fire test model and
are not concerned with the specific nature of the fire test.
This International Standard doesn’t cover aerosols (detailed in Reference [3]) and FTIR technique
(detailed in Reference [4]). The gases of environmental interest, such as PAH, dioxins, furans, endocrinal
disturbers, will be developed in a future document by ISO TC92/SC3.

Méthodes d'échantillonnage et d'analyse des effluents du feu

L'ISO 19701:2013 pr�sente un �ventail de techniques d'�chantillonnage et de m�thodes chimiques analytiques appropri�es � l'analyse des diff�rentes esp�ces chimiques en atmosph�res de combustion. Les modes op�ratoires concernent l'analyse d'�chantillons extraits d'un appareil ou d'un �coulement d'effluent � partir d'un appareil d'essai au feu ou d'un mod�le physique d'essai au feu, mais il ne rend pas compte de la nature sp�cifique de l'essai de combustion.
L'ISO 19701:2013 ne couvre pas les a�rosols et la technique de la spectroscopie infrarouge � transform�e de Fourier (IRTF).

Metode vzorčenja in analize dimnih plinov

Ta mednarodni standard predstavlja nabor metod vzorčenja in kemične analize, ki so primerne za
analizo posameznih kemijskih snovi v dimu. Postopki se nanašajo na analizo vzorcev, pridobljenih iz naprave ali pretoka dima iz požarne preskusne opreme ali fizikalnega preskusnega modela požara, in niso povezani s specifično naravo preskusa požarne varnosti.
Ta mednarodni standard ne zajema aerosolov (podrobno opisano v viru [3]) in tehnike FTIR (podrobno opisano v viru [4]). Plini, pomembni za varstvo okolja, kot so PAH, dioksini, furani in hormonski motilci, bodo obravnavali v prihodnjem dokumentu v standardu ISO TC92/SC3.

General Information

Status
Published
Public Enquiry End Date
29-Jul-2018
Publication Date
23-Aug-2018
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
13-Aug-2018
Due Date
18-Oct-2018
Completion Date
24-Aug-2018

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INTERNATIONAL ISO
STANDARD 19701
Second edition
2013-04-01
Methods for sampling and analysis of
fire effluents
Méthodes d’échantillonnage et d’analyse des effluents du feu
Reference number
ISO 19701:2013(E)
ISO 2013
---------------------- Page: 1 ----------------------
ISO 19701:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013

All rights reserved. Unless otherwise specified, 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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 19701:2013(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Methods of sampling ........................................................................................................................................................................................ 1

4.1 General considerations .................................................................................................................................................................... 1

4.2 Concentration and volume fraction ...................................................................................................................................... 2

4.3 Special considerations ...................................................................................................................................................................... 2

4.4 Sampling using gas-solution absorbers ............................................................................................................................. 3

4.5 Sampling using solid sorption tubes .................................................................................................................................... 5

4.6 Sampling for spectrometric or spectrophotometric analysis ......................................................................... 6

4.7 Sampling using gas bags ................................................................................................................................................................. 7

5 Analytical methods for fire gases ........................................................................................................................................................ 8

5.1 Carbon monoxide by non-dispersive infrared spectroscopy (NDIR) ....................................................... 8

5.2 Carbon dioxide by non dispersive infrared spectroscopy (NDIR) .............................................................. 9

5.3 Oxygen by paramagnetism ........................................................................................................................................................11

5.4 Hydrogen cyanide ..............................................................................................................................................................................12

5.5 Hydrogen chloride and hydrogen bromide .................................................................................................................18

5.6 Hydrogen fluoride .............................................................................................................................................................................25

5.7 Oxides of nitrogen .............................................................................................................................................................................29

5.8 Acrolein ......................................................................................................................................................................................................35

5.9 Formaldehyde .......................................................................................................................................................................................42

5.10 Acetaldehyde .........................................................................................................................................................................................47

5.11 Total aldehydes by colourimetry ..........................................................................................................................................48

5.12 Sulfur dioxide by high performance ion chromatography (HPIC) ...........................................................50

5.13 Carbon disulfide by GC-MS in gas phase ........................................................................................................................52

5.14 Hydrogen sulphide ...........................................................................................................................................................................54

5.15 Ammonia ...................................................................................................................................................................................................57

5.16 Antimony compounds by atomic absorption spectrophotometry (AAS) or inductively

coupled plasma emission spectrometry (ICP) ..........................................................................................................60

5.17 Arsenic compounds by atomic absorption spectrophotometry (AAS) or inductively

coupled plasma emission spectrometry (ICP) ..........................................................................................................62

5.18 Phosphorus by inductively coupled plasma emission spectrometry (ICP) .....................................63

5.19 Phosphates ..............................................................................................................................................................................................65

5.20 Phenol ..........................................................................................................................................................................................................69

5.21 Benzene ......................................................................................................................................................................................................72

5.22 Toluene (Methylbenzene) ...........................................................................................................................................................76

5.23 Styrene (Phenylethene) ................................................................................................................................................................80

5.24 Acrylonitrile and other nitriles by GC-MS in gas phase ....................................................................................83

5.25 Formic acid ..............................................................................................................................................................................................86

5.26 Total hydrocarbons by FID ......... ................................................................................................................................................89

5.27 Isocyanates ..............................................................................................................................................................................................89

5.28 Oxygenated organic species ......................................................................................................................................................89

Annex A (informative) Species and measurement techniques currently deemed unsuitable in

fire effluents ...........................................................................................................................................................................................................90

Annex B (informative) Colour-change chemical detection tubes ........................................................................................92

Annex C (informative) Quantitative instrumental methods .....................................................................................................93

Annex D (informative) Hydrogen fluoride by continuous online ion selective electrode ......................107

Bibliography .........................................................................................................................................................................................................................110

© ISO 2013 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 19701:2013(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International

Standards adopted by the technical committees are circulated to the member bodies for voting.

Publication as an International Standard requires approval by at least 75 % of the member bodies

casting a vote.

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.

ISO 19701 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 3, Fire threat

to people and environment.
This second edition cancels and replaces the first edition (ISO 19701:2005).
iv © ISO 2013 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 19701:2013(E)
Introduction

The analysis of fire gases for use in toxic hazard and life threat assessment and other purposes (e.g.

impact on the environment) is a great challenge for the analyst. Fire atmospheres are by nature hostile

environments. Temperatures in excess of 1 000 °C are common, the gas phase can contain many corrosive,

toxic, irritant or combustible species together with relatively large quantities of condensable water.

These properties are largely incompatible with most instrumental analytical methods where a “clean”

sample is required. This poses many problems both for the qualification and quantification of the chemical

species and particulates in fire atmospheres. In presenting a sample to the measuring instrument that it

will tolerate, it can be necessary to filter particulates and remove other species. Losses in the sampling

train must therefore be quantifiable and taken into account in the final analysis.

Techniques also exist for measuring chemical species in situ; this will be the subject of a future document.

The methods described in Clause 5 have been used successfully by a number of laboratories. Studies of

repeatability and reproducibility of many of the methods covered in this International Standard have

[1] [2]
been taken from AFNOR NF X70-100-1 and AFAP-3.

For methods that involve a commercial instrument, uncertainty in the measured values may be estimated

from the manufacturer’s data and other information, e.g. allowance for losses in the sampling process.

For other methods, uncertainty in the measured values can occur through a variety of reasons, such as

sensitivity to the strength of reagents or the visibility of a colourimetric end point. In these cases, it is

assumed that best practice by qualified personnel is applied.
This International Standard is structured as follows.
— Clause 1 describes the scope of this standard
— Clause 4 describes methods of sampling.
— Clause 5 describes analytical methods for gases in fire atmospheres:

— Annex A provides information on techniques that were found not suitable with fire effluents.

— Annex B briefly describes the use of aspirated chemical colour-change tubes.

— Annex C is a summary of the main instrumental methods available for fire gas analysis, expanding

the information provided under the clauses for each individual chemical species.

— Annex D presents a method for continuous measurement of HF concentration using ion selective

electrode.
© ISO 2013 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 19701:2013(E)
Methods for sampling and analysis of fire effluents

SAFETY PRECAUTIONS — Due consideration must be given to the fact that both the fire gases

for analysis and many of the reagents used for their analysis can be toxic and/or present serious

health hazards. It is assumed throughout that the procedures described in this document will

be carried out by suitably qualified professional personnel, adequately trained in the hazards

and risks associated with such analyses and aware of any safety regulations that may be in force.

Consideration must also be given to the safe and ecologically acceptable disposal of all chemicals

used for analyses. This can require extensive treatment prior to release of the waste into the

environment. Again, it is assumed in this document that the personnel responsible for the safe

disposal of such reagents are suitably qualified and trained in these techniques and are aware of

the regulations which may be in force.
1 Scope

This International Standard presents a range of sampling and chemical analytical methods suitable for

the analysis of individual chemical species in fire atmospheres. The procedures relate to the analysis of

samples extracted from an apparatus or effluent flow from a fire test rig or physical fire test model and

are not concerned with the specific nature of the fire test.

This International Standard doesn’t cover aerosols (detailed in Reference [3]) and FTIR technique

(detailed in Reference [4]). The gases of environmental interest, such as PAH, dioxins, furans, endocrinal

disturbers, will be developed in a future document by ISO TC92/SC3.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 13943, Fire safety — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 13943 apply.

4 Methods of sampling
4.1 General considerations

Sampling is perhaps the most critical part of the procedures for analysis of gases in fire effluents.

Whereas sampling and analysis are commonly in use for many gaseous species in other fields, sampling

from fire atmospheres presents unusual and difficult problems.

The sample presented to the analyser shall be as representative as possible of the test atmosphere,

without having been changed by the sampling system. The sampling procedure should influence the test

atmosphere as little as possible (e.g. by depletion of the test volume). The sampling procedure should be

as uncomplicated as possible, while incorporating all necessary features detailed in this International

Standard. The sampling procedure shall be capable of operating with minimal blockage in the sampling

lines, melting or other disruption of probes, and without allowing condensation of the species for analysis.

© ISO 2013 – All rights reserved 1
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ISO 19701:2013(E)

IMPORTANT — It is important to appreciate that the overall accuracy of the analysis of fire

effluent species is significantly dependent on the sampling procedures adopted, in particular

the quantification of losses in probes, sampling lines, and filtering systems.
4.2 Concentration and volume fraction

The concentration of fire effluent or of a toxic gas is its mass divided by the volume in which it is

contained. For a fire effluent the typical units are g.m .However, for a toxic gas, concentration is usually

expressed as a volume fraction at T = 298 K and P = 1 atm, and is expressed in terms of µL.L (equivalent

3 3 −6
to cm /m = 10 ).

NOTE 1 The concentration of a gas at a temperature, T, and a pressure, P can be calculated from its volume

fraction (assuming ideal gas behaviour) by multiplying the volume fraction by the density of the gas at that

temperature and pressure.

NOTE 2 Volume fractions of toxic gases used to be expressed in terms of “ppm by volume” but “ppm” is a

deprecated term and therefore “µL.L ” is now used.
4.3 Special considerations

There are many factors that have a direct influence on the specific type of sampling methodology selected

to ensure that a suitable sample is presented to the analyser. For example, consideration shall include

the range of concentrations anticipated, the limits of detection, reactivity of the species of interest,

presence of interferences, and peak and average concentration values. Sampling of the extremely

complex atmosphere produced during combustion requires a very thorough evaluation and assessment

of all potential factors that might affect optimum conditions for sample collection and analysis.

The large number of different products frequently encountered in fire effluents often requires the use

of a variety of sampling procedures and approaches to ensure accurate identification and quantification

of combustion products. The selected sampling procedure also depends on the instrumentation and

analytical procedures available for the specific species being measured.

Sampling may involve either continuous, online analysis (e.g. non-dispersive infrared) or non-continuous

batch sampling (e.g. evacuated flask or bubbler samples). Batch-type sampling can be further subdivided

into two categories:
a) “Instantaneous”, or “grab”;
b) Average, or integrated.

Although there is no sharp distinction between categories a) and b), it is generally understood that grab

samples relate to samples taken over a short time period (i.e. usually less than 1 min), whereas integrated

samples are usually taken over a longer time period (i.e. a substantial portion of the total test period).

In some cases, continuous or semi-continuous online or frequent instantaneous sampling can be well

suited for following the rapidly changing combustion environment and will provide a representative

concentration profile. Frequently however, the minimum detectable limit of the species of interest

requires larger sample volumes than can be taken with these techniques. If this analytical limitation

exists, it is necessary to carry out the sampling over a longer period. While using longer sampling

periods permits the analysis of lower concentrations, this approach has some limitations. For example,

these types of samples permit a determination only of the integrated average concentration obtained

over the sampling period and do not discern any abrupt change in the evolution of the species of interest.

However, abrupt concentration changes can also be missed with instantaneously obtained samples, if

samples are not taken frequently enough.

When batch-sampling procedures are used, it is essential to specify sampling frequency, the starting

time of each sample and the total sampling time. This information is essential in order to ensure proper

evaluation of the data in conjunction with other fire properties that are being monitored (e.g. heat

release, temperatures, mass loss, smoke evolution, flame spread).
2 © ISO 2013 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 19701:2013(E)

Test fires can be classified as “small” (laboratory or “bench” size), “intermediate” or “large” (usually

full-scale). The sampled gases can be hot or near room temperature. It is generally necessary to extract

the gases from the test atmosphere through suitable tubing using a suction pump. Stainless steel tubing,

as short as possible, is often used. In the case of the production of hot gases, the sampling line shall be

heated to at least 100 °C. Several analytical methods require a dry, particulate-free sample. Glass wool

may be used (in most cases) as a particulate filter, with another trap of a drying agent (e.g. calcium

sulfate or calcium chloride) for removing moisture. The traps should be located just before the analyser

and after any heated sections of sampling tubes. Simple cold traps are often insufficient to remove the

quantity of moisture present in fire effluents; however, they can be useful in conjunction with other

filters and traps. The individual sampling and analytical system being used dictates flow requirements

and the necessity for moisture removal. Precautions should be taken to minimize the volume of the

filtering systems to reduce sampling time.

With the exception of hydrogen fluoride (HF), acid gases shall be sampled using glass, epoxy-lined or

PTFE tubes to minimize losses due to reactivity and condensation on the tube surfaces. For hydrogen

fluoride, tubes lined with PTFE shall be used (glass and glass-lined tubes are unsuitable). For species

that are relatively reactive and prone to losses, sampling lines shall be as short as possible, and shall

be heated to a sufficient temperature to avoid condensation. Hydrogen chloride (HCl) and hydrogen

bromide (HBr) can be adsorbed onto soot particles as well as gas sampling lines (including PTFE lines).

For organic materials (e.g. acrolein), unlined stainless steel tubing is suitable but the sampling lines shall

be heated to avoid condensation. Particulate traps, although usually necessary, can be avoided in some

cases and instrument requirements should be checked in this regard.

The location and size of sampling probes is influenced by the size of the test apparatus and the

requirements of the analytical system. The positioning of sampling probes in specific apparatus, however,

is beyond the scope of this International Standard. In general, the possibility of the stratification of gases

in chambers without good mixing shall be considered and sampling too near the wall of a test chamber

should be avoided.

Calibration of the entire sampling and analysis system, rather than just the analysis system, is

recommended in order to ensure that any losses in the sample route can be allowed for. All calibrations

should, therefore, take into account such factors as gas leakage (both into and out of the sampling lines)

and the adsorption of gases onto probes, sampling lines, filters and other components. Calibration gases

are often obtainable in cylinders; however, it is advisable that the concentration stated by the supplier

be verified by an independent analysis. This is especially true of reactive gases such as HCl and HF,

which can decay over relatively short time periods even in a closed cylinder. The calibration gas shall be

introduced at the sampling probe and allowed to travel the same course as a test gas, through filters and

traps if present, to the analyser or sampling medium.
4.4 Sampling using gas-solution absorbers

Absorption of gases in solution by the use of gas-washing bottles, bubblers, impingers, etc. all rely on the

same principle. The test atmosphere is drawn or pushed through the absorbing media at a measured rate

for a specified period of time. At the end of the sampling period, the solution is analysed for the species of

interest (e.g. the chloride ion for absorption of hydrogen chloride gas in water). Assuming 100 % efficiency

© ISO 2013 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO 19701:2013(E)

(see discussion below), it is possible to calculate the concentration of the species in the gas phase, as

measured in the solution. A typical equation for calculating concentrations is presented in Formula (1):

ρ ××Vm(/m )
SG S
ρ = (1)
qt×
where
ρ is the gas concentration;
ρ is the solution concentration;
V is the volume, expressed in litres, of solution;

m /m is the ratio of atomic or molecular weights for the gaseous species, G, and solution species,

G S
S, if different, e.g. HCl/Cl);
q is the rate of gas flow, expressed in litres per minute, through the impinger;
t is the time, in minutes of gas flow.

The volume fraction of the gas, X , can be calculated by dividing the concentration by the density d,

of the gas at the ambient temperature and pressure. This density can be found, assuming ideal gas

behaviour, as follows:
d= (2)
X =ρ (3)
where
M is the molar mass of the gaseous species, G;

H is the gaseous volume occupied by 1 mol of an ideal gas at the relevant ambient pressure (P)

and temperature (T).[ H = 8,314 J.K-1.mol-1 × 1 mol × T/P ]
- −3

EXAMPLE Suppose that the measured solution concentration of chloride ion (Cl ) was 0,006 g × dm in

0,025 dm of solution, the ambient thermodynamic temperature was 293,15 K, the ambient pressure was 1 bar

5 5 −3 3

(10 Pa = 10 J × m ), and the flow rate of gas was 0,25 dm /min for 2 min. Then the gas concentration of hydrogen

chloride is given by:
−3 3 3
ρG = [0,006 g.dm x 0,025 dm x (36,461 / 35,453)] / [0,25 dm /min x 2 min]
ρG = [0,00015 g x 1,028] / 0,50 dm
−3 −3
ρG = 0,0003084 g.dm = 308,4 mg.m
The volume fraction of hydrogen chloride is given by:
−3 −1 −1 −3 −1
X = 308,4 mg.m x (8,314 J.K .mol x 293,15 K / 105 J.m ) / 36,461 g.mol
−3 3 −1 −1
X = 308,4 mg.m x 0,02437 m .mol / 36,461 g.mol
X = 0,0002061 = 206,1 µL/L

The volume of the absorber solution and the total flow of gas directly affect the ratio of the gas and

solution concentrations. For a given gas concentration, the smaller the solution volume and/or the

larger the gas volume sampled, the higher the solution concentration. The choice of sampling conditions

4 © ISO 2013 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 19701:2013(E)

is dictated by the requirements of the analytical technique, including the volume and sampling rate

tolerated, expected concentration of gas in the test atmosphere, necessity for frequent sampling, etc.

The efficiency of absorption of a gas in liquid is affected by the following:
a) Solubility of the gas in the solution;
b) Physical characteristics of the absorber;
c) Ratio of gas flow rate to solution volume.

Generally, absorption efficiency is estimated empirically by allowing the flow of a known concentration

of the gas of interest through a series of impingers and measuring the “break-through” from the first

impinger (i.e. whatever is collected in the other traps). Another check on the efficiency of a given

flow/impinger system is to conduct a series of experiments with a known concentration of gas, using

different impingers and various flow rates. In practice, however, the choice of apparatus is limited, and

gas flow rates and trapping solution volumes are based on Formula (1), taking into account the known

characteristics of the analysis methods.

There are basically four types of gas-solution absorbers: simple gas-washing bottles (including midget

impingers), spiral or helical absorbers, packed glass-bead columns and fritted bubblers. The gas-washing

bottles, or impingers, function by drawing the gas through a tube (usually with a constricted opening),

which is immersed in the trapping liquid/solution. This type is most suitable for highly soluble gases

because contact time between solution and gas is short and bubble size is relatively large. For less soluble

species, the other absorbers offer longer contact time and/or smaller bubble size (which increases relative

surface contact). The spiral or helical absorbers are built in specialized shapes to allow a long contact

time. The flow rate in these bubblers is limited because of the possibility of trapping solution over-flow

with high flow rates. Packed glass-bead columns allow increased gas/liquid contact by dispersing the

bubbles through a bed of glass beads. Flow rates can be higher than for the spiral absorbers.

The
...

SLOVENSKI STANDARD
SIST ISO 19701:2018
01-september-2018
1DGRPHãþD
SIST ISO/TR 9122-3:1999
0HWRGHY]RUþHQMDLQDQDOL]HGLPQLKSOLQRY
Methods for sampling and analysis of fire effluents
Méthodes d'échantillonnage et d'analyse des effluents du feu
Ta slovenski standard je istoveten z: ISO 19701:2013
ICS:
13.220.99 Drugi standardi v zvezi z Other standards related to
varstvom pred požarom protection against fire
SIST ISO 19701:2018 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ISO 19701:2018
---------------------- Page: 2 ----------------------
SIST ISO 19701:2018
INTERNATIONAL ISO
STANDARD 19701
Second edition
2013-04-01
Methods for sampling and analysis of
fire effluents
Méthodes d’échantillonnage et d’analyse des effluents du feu
Reference number
ISO 19701:2013(E)
ISO 2013
---------------------- Page: 3 ----------------------
SIST ISO 19701:2018
ISO 19701:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013

All rights reserved. Unless otherwise specified, 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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 19701:2018
ISO 19701:2013(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Methods of sampling ........................................................................................................................................................................................ 1

4.1 General considerations .................................................................................................................................................................... 1

4.2 Concentration and volume fraction ...................................................................................................................................... 2

4.3 Special considerations ...................................................................................................................................................................... 2

4.4 Sampling using gas-solution absorbers ............................................................................................................................. 3

4.5 Sampling using solid sorption tubes .................................................................................................................................... 5

4.6 Sampling for spectrometric or spectrophotometric analysis ......................................................................... 6

4.7 Sampling using gas bags ................................................................................................................................................................. 7

5 Analytical methods for fire gases ........................................................................................................................................................ 8

5.1 Carbon monoxide by non-dispersive infrared spectroscopy (NDIR) ....................................................... 8

5.2 Carbon dioxide by non dispersive infrared spectroscopy (NDIR) .............................................................. 9

5.3 Oxygen by paramagnetism ........................................................................................................................................................11

5.4 Hydrogen cyanide ..............................................................................................................................................................................12

5.5 Hydrogen chloride and hydrogen bromide .................................................................................................................18

5.6 Hydrogen fluoride .............................................................................................................................................................................25

5.7 Oxides of nitrogen .............................................................................................................................................................................29

5.8 Acrolein ......................................................................................................................................................................................................35

5.9 Formaldehyde .......................................................................................................................................................................................42

5.10 Acetaldehyde .........................................................................................................................................................................................47

5.11 Total aldehydes by colourimetry ..........................................................................................................................................48

5.12 Sulfur dioxide by high performance ion chromatography (HPIC) ...........................................................50

5.13 Carbon disulfide by GC-MS in gas phase ........................................................................................................................52

5.14 Hydrogen sulphide ...........................................................................................................................................................................54

5.15 Ammonia ...................................................................................................................................................................................................57

5.16 Antimony compounds by atomic absorption spectrophotometry (AAS) or inductively

coupled plasma emission spectrometry (ICP) ..........................................................................................................60

5.17 Arsenic compounds by atomic absorption spectrophotometry (AAS) or inductively

coupled plasma emission spectrometry (ICP) ..........................................................................................................62

5.18 Phosphorus by inductively coupled plasma emission spectrometry (ICP) .....................................63

5.19 Phosphates ..............................................................................................................................................................................................65

5.20 Phenol ..........................................................................................................................................................................................................69

5.21 Benzene ......................................................................................................................................................................................................72

5.22 Toluene (Methylbenzene) ...........................................................................................................................................................76

5.23 Styrene (Phenylethene) ................................................................................................................................................................80

5.24 Acrylonitrile and other nitriles by GC-MS in gas phase ....................................................................................83

5.25 Formic acid ..............................................................................................................................................................................................86

5.26 Total hydrocarbons by FID ......... ................................................................................................................................................89

5.27 Isocyanates ..............................................................................................................................................................................................89

5.28 Oxygenated organic species ......................................................................................................................................................89

Annex A (informative) Species and measurement techniques currently deemed unsuitable in

fire effluents ...........................................................................................................................................................................................................90

Annex B (informative) Colour-change chemical detection tubes ........................................................................................92

Annex C (informative) Quantitative instrumental methods .....................................................................................................93

Annex D (informative) Hydrogen fluoride by continuous online ion selective electrode ......................107

Bibliography .........................................................................................................................................................................................................................110

© ISO 2013 – All rights reserved iii
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SIST ISO 19701:2018
ISO 19701:2013(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International

Standards adopted by the technical committees are circulated to the member bodies for voting.

Publication as an International Standard requires approval by at least 75 % of the member bodies

casting a vote.

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.

ISO 19701 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 3, Fire threat

to people and environment.
This second edition cancels and replaces the first edition (ISO 19701:2005).
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Introduction

The analysis of fire gases for use in toxic hazard and life threat assessment and other purposes (e.g.

impact on the environment) is a great challenge for the analyst. Fire atmospheres are by nature hostile

environments. Temperatures in excess of 1 000 °C are common, the gas phase can contain many corrosive,

toxic, irritant or combustible species together with relatively large quantities of condensable water.

These properties are largely incompatible with most instrumental analytical methods where a “clean”

sample is required. This poses many problems both for the qualification and quantification of the chemical

species and particulates in fire atmospheres. In presenting a sample to the measuring instrument that it

will tolerate, it can be necessary to filter particulates and remove other species. Losses in the sampling

train must therefore be quantifiable and taken into account in the final analysis.

Techniques also exist for measuring chemical species in situ; this will be the subject of a future document.

The methods described in Clause 5 have been used successfully by a number of laboratories. Studies of

repeatability and reproducibility of many of the methods covered in this International Standard have

[1] [2]
been taken from AFNOR NF X70-100-1 and AFAP-3.

For methods that involve a commercial instrument, uncertainty in the measured values may be estimated

from the manufacturer’s data and other information, e.g. allowance for losses in the sampling process.

For other methods, uncertainty in the measured values can occur through a variety of reasons, such as

sensitivity to the strength of reagents or the visibility of a colourimetric end point. In these cases, it is

assumed that best practice by qualified personnel is applied.
This International Standard is structured as follows.
— Clause 1 describes the scope of this standard
— Clause 4 describes methods of sampling.
— Clause 5 describes analytical methods for gases in fire atmospheres:

— Annex A provides information on techniques that were found not suitable with fire effluents.

— Annex B briefly describes the use of aspirated chemical colour-change tubes.

— Annex C is a summary of the main instrumental methods available for fire gas analysis, expanding

the information provided under the clauses for each individual chemical species.

— Annex D presents a method for continuous measurement of HF concentration using ion selective

electrode.
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SIST ISO 19701:2018
INTERNATIONAL STANDARD ISO 19701:2013(E)
Methods for sampling and analysis of fire effluents

SAFETY PRECAUTIONS — Due consideration must be given to the fact that both the fire gases

for analysis and many of the reagents used for their analysis can be toxic and/or present serious

health hazards. It is assumed throughout that the procedures described in this document will

be carried out by suitably qualified professional personnel, adequately trained in the hazards

and risks associated with such analyses and aware of any safety regulations that may be in force.

Consideration must also be given to the safe and ecologically acceptable disposal of all chemicals

used for analyses. This can require extensive treatment prior to release of the waste into the

environment. Again, it is assumed in this document that the personnel responsible for the safe

disposal of such reagents are suitably qualified and trained in these techniques and are aware of

the regulations which may be in force.
1 Scope

This International Standard presents a range of sampling and chemical analytical methods suitable for

the analysis of individual chemical species in fire atmospheres. The procedures relate to the analysis of

samples extracted from an apparatus or effluent flow from a fire test rig or physical fire test model and

are not concerned with the specific nature of the fire test.

This International Standard doesn’t cover aerosols (detailed in Reference [3]) and FTIR technique

(detailed in Reference [4]). The gases of environmental interest, such as PAH, dioxins, furans, endocrinal

disturbers, will be developed in a future document by ISO TC92/SC3.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 13943, Fire safety — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 13943 apply.

4 Methods of sampling
4.1 General considerations

Sampling is perhaps the most critical part of the procedures for analysis of gases in fire effluents.

Whereas sampling and analysis are commonly in use for many gaseous species in other fields, sampling

from fire atmospheres presents unusual and difficult problems.

The sample presented to the analyser shall be as representative as possible of the test atmosphere,

without having been changed by the sampling system. The sampling procedure should influence the test

atmosphere as little as possible (e.g. by depletion of the test volume). The sampling procedure should be

as uncomplicated as possible, while incorporating all necessary features detailed in this International

Standard. The sampling procedure shall be capable of operating with minimal blockage in the sampling

lines, melting or other disruption of probes, and without allowing condensation of the species for analysis.

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IMPORTANT — It is important to appreciate that the overall accuracy of the analysis of fire

effluent species is significantly dependent on the sampling procedures adopted, in particular

the quantification of losses in probes, sampling lines, and filtering systems.
4.2 Concentration and volume fraction

The concentration of fire effluent or of a toxic gas is its mass divided by the volume in which it is

contained. For a fire effluent the typical units are g.m .However, for a toxic gas, concentration is usually

expressed as a volume fraction at T = 298 K and P = 1 atm, and is expressed in terms of µL.L (equivalent

3 3 −6
to cm /m = 10 ).

NOTE 1 The concentration of a gas at a temperature, T, and a pressure, P can be calculated from its volume

fraction (assuming ideal gas behaviour) by multiplying the volume fraction by the density of the gas at that

temperature and pressure.

NOTE 2 Volume fractions of toxic gases used to be expressed in terms of “ppm by volume” but “ppm” is a

deprecated term and therefore “µL.L ” is now used.
4.3 Special considerations

There are many factors that have a direct influence on the specific type of sampling methodology selected

to ensure that a suitable sample is presented to the analyser. For example, consideration shall include

the range of concentrations anticipated, the limits of detection, reactivity of the species of interest,

presence of interferences, and peak and average concentration values. Sampling of the extremely

complex atmosphere produced during combustion requires a very thorough evaluation and assessment

of all potential factors that might affect optimum conditions for sample collection and analysis.

The large number of different products frequently encountered in fire effluents often requires the use

of a variety of sampling procedures and approaches to ensure accurate identification and quantification

of combustion products. The selected sampling procedure also depends on the instrumentation and

analytical procedures available for the specific species being measured.

Sampling may involve either continuous, online analysis (e.g. non-dispersive infrared) or non-continuous

batch sampling (e.g. evacuated flask or bubbler samples). Batch-type sampling can be further subdivided

into two categories:
a) “Instantaneous”, or “grab”;
b) Average, or integrated.

Although there is no sharp distinction between categories a) and b), it is generally understood that grab

samples relate to samples taken over a short time period (i.e. usually less than 1 min), whereas integrated

samples are usually taken over a longer time period (i.e. a substantial portion of the total test period).

In some cases, continuous or semi-continuous online or frequent instantaneous sampling can be well

suited for following the rapidly changing combustion environment and will provide a representative

concentration profile. Frequently however, the minimum detectable limit of the species of interest

requires larger sample volumes than can be taken with these techniques. If this analytical limitation

exists, it is necessary to carry out the sampling over a longer period. While using longer sampling

periods permits the analysis of lower concentrations, this approach has some limitations. For example,

these types of samples permit a determination only of the integrated average concentration obtained

over the sampling period and do not discern any abrupt change in the evolution of the species of interest.

However, abrupt concentration changes can also be missed with instantaneously obtained samples, if

samples are not taken frequently enough.

When batch-sampling procedures are used, it is essential to specify sampling frequency, the starting

time of each sample and the total sampling time. This information is essential in order to ensure proper

evaluation of the data in conjunction with other fire properties that are being monitored (e.g. heat

release, temperatures, mass loss, smoke evolution, flame spread).
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Test fires can be classified as “small” (laboratory or “bench” size), “intermediate” or “large” (usually

full-scale). The sampled gases can be hot or near room temperature. It is generally necessary to extract

the gases from the test atmosphere through suitable tubing using a suction pump. Stainless steel tubing,

as short as possible, is often used. In the case of the production of hot gases, the sampling line shall be

heated to at least 100 °C. Several analytical methods require a dry, particulate-free sample. Glass wool

may be used (in most cases) as a particulate filter, with another trap of a drying agent (e.g. calcium

sulfate or calcium chloride) for removing moisture. The traps should be located just before the analyser

and after any heated sections of sampling tubes. Simple cold traps are often insufficient to remove the

quantity of moisture present in fire effluents; however, they can be useful in conjunction with other

filters and traps. The individual sampling and analytical system being used dictates flow requirements

and the necessity for moisture removal. Precautions should be taken to minimize the volume of the

filtering systems to reduce sampling time.

With the exception of hydrogen fluoride (HF), acid gases shall be sampled using glass, epoxy-lined or

PTFE tubes to minimize losses due to reactivity and condensation on the tube surfaces. For hydrogen

fluoride, tubes lined with PTFE shall be used (glass and glass-lined tubes are unsuitable). For species

that are relatively reactive and prone to losses, sampling lines shall be as short as possible, and shall

be heated to a sufficient temperature to avoid condensation. Hydrogen chloride (HCl) and hydrogen

bromide (HBr) can be adsorbed onto soot particles as well as gas sampling lines (including PTFE lines).

For organic materials (e.g. acrolein), unlined stainless steel tubing is suitable but the sampling lines shall

be heated to avoid condensation. Particulate traps, although usually necessary, can be avoided in some

cases and instrument requirements should be checked in this regard.

The location and size of sampling probes is influenced by the size of the test apparatus and the

requirements of the analytical system. The positioning of sampling probes in specific apparatus, however,

is beyond the scope of this International Standard. In general, the possibility of the stratification of gases

in chambers without good mixing shall be considered and sampling too near the wall of a test chamber

should be avoided.

Calibration of the entire sampling and analysis system, rather than just the analysis system, is

recommended in order to ensure that any losses in the sample route can be allowed for. All calibrations

should, therefore, take into account such factors as gas leakage (both into and out of the sampling lines)

and the adsorption of gases onto probes, sampling lines, filters and other components. Calibration gases

are often obtainable in cylinders; however, it is advisable that the concentration stated by the supplier

be verified by an independent analysis. This is especially true of reactive gases such as HCl and HF,

which can decay over relatively short time periods even in a closed cylinder. The calibration gas shall be

introduced at the sampling probe and allowed to travel the same course as a test gas, through filters and

traps if present, to the analyser or sampling medium.
4.4 Sampling using gas-solution absorbers

Absorption of gases in solution by the use of gas-washing bottles, bubblers, impingers, etc. all rely on the

same principle. The test atmosphere is drawn or pushed through the absorbing media at a measured rate

for a specified period of time. At the end of the sampling period, the solution is analysed for the species of

interest (e.g. the chloride ion for absorption of hydrogen chloride gas in water). Assuming 100 % efficiency

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(see discussion below), it is possible to calculate the concentration of the species in the gas phase, as

measured in the solution. A typical equation for calculating concentrations is presented in Formula (1):

ρ ××Vm(/m )
SG S
ρ = (1)
qt×
where
ρ is the gas concentration;
ρ is the solution concentration;
V is the volume, expressed in litres, of solution;

m /m is the ratio of atomic or molecular weights for the gaseous species, G, and solution species,

G S
S, if different, e.g. HCl/Cl);
q is the rate of gas flow, expressed in litres per minute, through the impinger;
t is the time, in minutes of gas flow.

The volume fraction of the gas, X , can be calculated by dividing the concentration by the density d,

of the gas at the ambient temperature and pressure. This density can be found, assuming ideal gas

behaviour, as follows:
d= (2)
X =ρ (3)
where
M is the molar mass of the gaseous species, G;

H is the gaseous volume occupied by 1 mol of an ideal gas at the relevant ambient pressure (P)

and temperature (T).[ H = 8,314 J.K-1.mol-1 × 1 mol × T/P ]
- −3

EXAMPLE Suppose that the measured solution concentration of chloride ion (Cl ) was 0,006 g × dm in

0,025 dm of solution, the ambient thermodynamic temperature was 293,15 K, the ambient pressure was 1 bar

5 5 −3 3

(10 Pa = 10 J × m ), and the flow rate of gas was 0,25 dm /min for 2 min. Then the gas concentration of hydrogen

chloride is given by:
−3 3 3
ρG = [0,006 g.dm x 0,025 dm x (36,461 / 35,453)] / [0,25 dm /min x 2 min]
ρG = [0,00015 g x 1,028] / 0,50 dm
−3 −3
ρG = 0,0003084 g.dm = 308,4 mg.m
The volume fraction of hydrogen chloride is given by:
−3 −1 −1 −3 −1
X = 308,4 mg.m x (8,314 J.K .mol x 293,15 K / 105 J.m ) / 36,461 g.mol
−3 3 −1 −1
X = 308,4 mg.m x 0,02437 m .mol / 36,461 g.mol
X = 0,0002061 = 206,1 µL/L

The volume of the absorber solution and the total flow of gas directly affect the ratio of the gas and

solution concentrations. For a given gas concentration, the smaller the solution volume and/or the

larger the gas volume sampled, the higher the solution concentration. The choice of sampling conditions

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is dictated by the requirements of the analytical technique, including the volume and sampling rate

tolerated, expected concentration of gas in the test atmosphere, necessity for frequent sampling, etc.

The efficiency of absorption of a gas in liquid is affected by the following:
a) Solubility of the gas in the solution;
b) Physical characteristics of the absorber;
c) Ratio of gas flow rate to solution volume.

Generally, absorption efficiency is estimated empirically by allowing the flow of a known concentration

of the gas of interest through a series of impingers and measuring the “break-through” from the first

impinger (i.e. whatever is collected in the other traps). Another check on the efficiency of a given

flow/impinger system is to conduct a series of experiments with a known concentration of gas, using

different impingers and various flow rates. In practice, however, the choice of apparatus is limited, and

gas flow rates and trapping solution volumes are based on Formula (1), taking into account the known

characteristics of the analysis methods.
There are basically four types of gas-solution absorbers: simple
...

NORME ISO
INTERNATIONALE 19701
Deuxième édition
2013-04-01
Méthodes d’échantillonnage et
d’analyse des effluents du feu
Methods for sampling and analysis of fire effluents
Numéro de référence
ISO 19701:2013(F)
ISO 2013
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ISO 19701:2013(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2013

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni utilisée

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ii © ISO 2013 – Tous droits réservés
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ISO 19701:2013(F)
Sommaire Page

Avant-propos ..............................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Domaine d’application ................................................................................................................................................................................... 1

2 Références normatives ................................................................................................................................................................................... 1

3 Termes et définitions ....................................................................................................................................................................................... 1

4 Méthodes d’échantillonnage .................................................................................................................................................................... 1

4.1 Considérations générales ............................................................................................................................................................... 1

4.2 Concentration et fraction volumique ................................................................................................................................... 2

4.3 Considérations spéciales ................................................................................................................................................................ 2

4.4 Échantillonnage en utilisant des solutions d’absorption de gaz .................................................................. 4

4.5 Échantillonnage utilisant des tubes de sorption solides .................................................................................... 6

4.6 Prélèvement pour l’analyse spectrométrique ou spectrophotométrique ............................................ 7

4.7 Échantillonnage à l’aide de sacs à gaz ................................................................................................................................. 7

5 Méthodes analytiques pour les gaz de combustion ......................................................................................................... 8

5.1 Monoxyde de carbone par spectroscopie infrarouge non dispersive (IRND) .................................. 8

5.2 Dioxyde de carbone par spectroscopie infrarouge non dispersive (IRND) .....................................10

5.3 Oxygène par paramagnétisme ................................................................................................................................................12

5.4 Cyanure d’hydrogène ......................................................................................................................................................................13

5.5 Chlorure d’hydrogène et bromure d’hydrogène .....................................................................................................20

5.6 Fluorure d’hydrogène ....................................................................................................................................................................27

5.7 Oxydes d’azote ......................................................................................................................................................................................32

5.8 Acroléine ...................................................................................................................................................................................................38

5.9 Formaldéhyde .......................................................................................................................................................................................45

5.10 Acétaldéhyde .........................................................................................................................................................................................51

5.11 Aldéhydes totaux par colorimétrie .....................................................................................................................................51

5.12 Dioxyde de soufre par chromatographie ionique à haute performance (CLI-HP) .....................53

5.13 Disulfure de carbone par CPG/SM en phase gazeuse .........................................................................................55

5.14 Sulfure d’hydrogène.........................................................................................................................................................................57

5.15 Ammoniac ................................................................................................................................................................................................60

5.16 Composés antimoniques par spectrophotométrie d’absorption atomique (AAS) ou

spectrométrie d’émission plasma par couplage inductif (ICP) ..................................................................64

5.17 Composés de l’arsenic par spectrophotométrie d’absorption atomique (AAS) ou

spectrométrie d’émission plasma par couplage inductif (ICP) ..................................................................66

5.18 Phosphore par spectrométrie d’émission plasma par couplage inductif (ICP) ...........................67

5.19 Phosphates ..............................................................................................................................................................................................69

5.20 Phénol ..........................................................................................................................................................................................................73

5.21 Benzène ......................................................................................................................................................................................................77

5.22 Toluène (Méthylbenzène) ...........................................................................................................................................................80

5.23 Styrène (Phénylethène) ................................................................................................................................................................84

5.24 Acrylonitrile et autres nitriles par CPG/SM en phase gazeuse ...................................................................88

5.25 Acide formique .....................................................................................................................................................................................90

5.26 Hydrocarbures totaux par FID ................................................................................................................................................94

5.27 Isocyanates ..............................................................................................................................................................................................94

5.28 Espèces organiques oxygénées ..............................................................................................................................................94

Annexe A (informative) Espèces et techniques de mesure actuellement considérées comme

inadaptées aux effluents du feu .........................................................................................................................................................95

Annexe B (informative) Tubes colorimétriques pour la détection de produits chimiques......................97

Annexe C (informative) Méthodes quantitatives instrumentales .......................................................................................98

Annexe D (informative) Fluorure d’hydrogène par électrode sélective d’ions continue en ligne .112

Bibliographie .......................................................................................................................................................................................................................115

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ISO 19701:2013(F)
Avant-propos

L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes

nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est

en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude

a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,

gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.

L’ISO collabore étroitement avec la Commission électrotechnique internationale (CEI) en ce qui concerne

la normalisation électrotechnique.

Les Normes internationales sont rédigées conformément aux règles données dans les Directives

ISO/CEI, Partie 2.

La tâche principale des comités techniques est d’élaborer les Normes internationales. Les projets de

Normes internationales adoptés par les comités techniques sont soumis aux comités membres pour vote.

Leur publication comme Normes internationales requiert l’approbation de 75 % au moins des comités

membres votants.

L’attention est appelée sur le fait que certains des éléments du présent document peuvent faire l’objet de

droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable de

ne pas avoir identifié de tels droits de propriété et averti de leur existence.

L’ISO 19701 a été élaborée par le comité technique ISO/TC 92, Sécurité au feu, sous-comité SC 3, Dangers

pour les personnes et l’environnement dus au feu.
Cette deuxième édition annule et remplace la première édition (ISO 19701:2005).
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ISO 19701:2013(F)
Introduction

L’analyse des gaz de combustion utilisée dans l’évaluation des risques toxiques et de menace sur la vie,

ainsi que pour d’autres utilisations (par exemple l’impact sur l’environnement) est un grand défi pour

l’analyste. Les atmosphères de combustion sont par nature des environnements hostiles. Des températures

dépassant 1 000 °C sont courantes, la phase gazeuse peut contenir de nombreuses espèces corrosives,

toxiques, irritantes ou combustibles, ainsi que des quantités relativement élevées d’eau condensable.

Ces propriétés sont largement incompatibles avec la plupart des méthodes analytiques instrumentales,

où un échantillon propre est requis. Cela pose de nombreux problèmes pour la qualification et la

quantification des espèces et particules chimiques en atmosphères de combustion. Pour qu’un échantillon

présenté à l’instrument de mesure soit toléré, il peut être nécessaire de filtrer les particules et d’éliminer

d’autres espèces. Les pertes dans le système d’échantillonnage doivent donc être quantifiables et prises

en compte dans l’analyse finale.

Des techniques pour mesurer les espèces chimiques in situ existent également; cela fera l’objet d’un

futur document.

Les méthodes décrites dans l’Article 5 ont été employées avec succès par un certain nombre de

laboratoires. Des études de répétabilité et de reproductibilité de plusieurs méthodes couvertes dans la

[1] [2]

présente Norme internationale ont été décrites dans la norme NF X 70-100-1 et la norme AFAP-3.

Pour les méthodes qui impliquent l’utilisation d’un instrument commercial, l’incertitude sur les valeurs

mesurées peut être estimée à partir des données du fabricant et de toute autre information, par exemple

la répartition des pertes dans le procédé d’échantillonnage. Pour d’autres méthodes, l’incertitude sur

les valeurs mesurées peut se produire à cause de diverses raisons, telles que la sensibilité à la force des

réactifs ou la visibilité d’un point final en colorimétrie. Dans ces cas-là, il est supposé que des pratiques

d’excellence sont appliquées par le personnel qualifié.

Les gaz qui présentent un danger pour l’environnement, tels que les hydrocarbures aromatiques

polycycliques (HAP), les dioxines, les furanes et les perturbateurs du système endocrinien, seront traités

dans un futur document.
La présente Norme internationale est structurée de la façon suivante:

— l’Article 1 décrit le domaine d’application de la présente Norme internationale;

— l’Article 4 décrit les méthodes d’échantillonnage;

— l’Article 5 décrit les méthodes d’analyses des gaz dans l’atmosphère de combustion;

— l’Annexe A fournit des informations sur des techniques qui se sont révélées inadaptées aux

effluents du feu;

— l’Annexe B décrit brièvement l’utilisation de tubes colorimétriques à aspiration de composés chimiques;

— l’Annexe C est un sommaire des principales méthodes instrumentales disponibles pour l’analyse

de gaz d’incendie, étendant ainsi les informations fournies dans les différents articles, pour chaque

espèce chimique;

— l’Annexe D présente une méthode de mesure continue de la concentration en fluorure d’hydrogène

(HF) par électrode ionique sélective.
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Méthodes d’échantillonnage et d’analyse des effluents du feu

PRÉCAUTIONS DE SÉCURITÉ — L’attention doit être attirée sur le fait que les gaz de combustion

à analyser d’une part, et les nombreux réactifs utilisés pour leurs analyses d’autre part, peuvent

être toxiques et présenter des risques sanitaires sérieux. Il est donc admis que les modes

opératoires décrits dans ce document seront effectués par un personnel professionnel qualifié,

ayant en conséquence une formation adéquate en risques d’hygiène et de sécurité, associés à

de telles analyses, ainsi qu’en règles d’hygiène et de sécurité qui sont en vigueur. L’attention

doit également être portée à l’élimination sans danger et écologiquement acceptable de tous

les produits chimiques utilisés pour les analyses. Cela peut exiger un traitement poussé avant

l’élimination des déchets dans l’environnement. On admet de nouveau dans ce document que le

personnel responsable de l’élimination de tels réactifs en toute sécurité est adéquatement formé

dans ces techniques et est au courant des règlements d’hygiène et de sécurité en vigueur.

1 Domaine d’application

La présente Norme internationale présente un éventail de techniques d’échantillonnage et de méthodes

chimiques analytiques appropriées à l’analyse des différentes espèces chimiques en atmosphères de

combustion. Les modes opératoires concernent l’analyse d’échantillons extraits d’un appareil ou d’un

écoulement d’effluent à partir d’un appareil d’essai au feu ou d’un modèle physique d’essai au feu, mais il

ne rend pas compte de la nature spécifique de l’essai de combustion.

La présente Norme internationale ne couvre pas les aérosols (détaillés en Référence [3]) et la technique

de la spectroscopie infrarouge à transformée de Fourier (IRTF) (détaillée en Référence [4]).

2 Références normatives

Les documents ci-après, dans leur intégralité ou non, sont des références normatives indispensables

à l’application du présent document. Pour les références datées, seule l’édition citée s’applique. Pour

les références non datées, la dernière édition du document de référence (y compris les éventuels

amendements) s’applique.
ISO 13943, Sécurité au feu — Vocabulaire
3 Termes et définitions

Pour les besoins du présent document, les termes et définitions donnés dans l’ISO 13943 s’appliquent.

4 Méthodes d’échantillonnage
4.1 Considérations générales

L’échantillonnage est peut-être la partie la plus critique des modes opératoires, pour l’analyse des gaz dans

les effluents du feu. Alors que, dans d’autres domaines, l’échantillonnage et l’analyse sont couramment

utilisés pour de nombreuses espèces, l’échantillonnage dans les atmosphères de combustion présente

des problèmes peu communs et difficiles.

L’échantillon présenté à l’analyseur doit être aussi représentatif que possible de l’atmosphère d’essai,

sans modification provoquée par le système d’échantillonnage. Il convient que le mode opératoire

d’échantillonnage influence le moins possible l’atmosphère d’essai (par exemple par appauvrissement

du volume d’essai). Il convient que le mode opératoire d’échantillonnage soit aussi peu compliqué

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que possible, tout en incorporant tous les dispositifs nécessaires détaillés dans la présente Norme

internationale. Le mode opératoire d’échantillonnage doit être capable de fonctionner avec un blocage

minimal des lignes d’échantillonnage, avec fusion ou autre perturbation des sondes minimale, et sans

permettre la condensation des espèces à analyser.

IMPORTANT — Il est important de comprendre que l’exactitude globale de l’analyse des espèces

issues des effluents du feu dépend en grande partie des modes opératoires d’échantillonnage

adoptés, en particulier la quantification des pertes dans les sondes, les lignes d’échantillonnage

et les systèmes de filtrage.
4.2 Concentration et fraction volumique

La concentration des effluents du feu ou d’un gaz toxique est le quotient de sa masse par le volume qui

la contient. Pour les effluents du feu, elle est exprimée en grammes par mètre cube (g.m ). Cependant,

pour un gaz toxique, la concentration s’exprime généralement en fraction volumique à T = 298 K et P = 1

−1 3 3 −6

atm, et est exprimée en microlitres par litre (µL.L ) (équivalent à cm /m = 10 ).

NOTE 1 La concentration d’un gaz à la température T et à la pression P peut être calculée à partir de sa fraction

volumique (si le gaz peut être assimilé à un gaz parfait) en multipliant la fraction volumique par la masse volumique

du gaz dans les mêmes conditions de température et de pression.

NOTE 2 Les fractions volumiques des gaz toxiques utilisés doivent s’exprimer en « ppm par volume » mais

« ppm » est un terme déconseillé et par conséquent « µL.L » est actuellement utilisé.

4.3 Considérations spéciales

Il existe de nombreux facteurs influençant directement le type spécifique de modes opératoires

d’échantillonnage choisi, afin de s’assurer qu’un échantillon adapté est fourni à l’analyseur. Par exemple,

les critères de sélection doivent inclure la plage des concentrations prévues, les limites de détection,

la réactivité des espèces présentant un intérêt, la présence d’interférences et les valeurs maximales et

moyennes de concentration. L’échantillonnage de l’atmosphère, extrêmement complexe et produite lors

de la combustion, exige une évaluation très complète de tous les facteurs potentiels qui affecteraient les

conditions optimales de collecte et d’analyse de l’échantillon.

Le grand nombre des différents produits fréquemment rencontrés dans les effluents du feu exige

souvent l’utilisation de plusieurs approches et de plusieurs méthodes d’échantillonnage, afin d’assurer

une identification et une quantification précises des produits de combustion. Le mode opératoire

d’échantillonnage choisi dépendra également des instruments et des méthodes analytiques disponibles

pour les espèces spécifiques à mesurer.

L’échantillonnage peut comporter l’analyse continue en ligne (par exemple infrarouge non dispersif) ou

non continue avec prélèvement en lots d’échantillons (par exemple échantillon dans un ballon sous vide

ou flacon laveur). L’échantillonnage en lots peut être encore subdivisé en deux catégories:

a) échantillonnage « instantané »;
b) échantillonnage « moyen » (ou intégré).

Bien qu’il n’y ait aucune distinction nette entre les catégories a) et b), on admet généralement que les

échantillonnages instantanés concernent les échantillons prélevés sur des périodes de temps courtes

(c’est-à-dire < 1 min en général), tandis que les échantillonnages intégrés sont en général prélevés sur

une période de temps plus longue (soit une partie significative de la période d’essai totale).

Dans certains cas, l’échantillonnage en ligne continu ou semi-continu ou l’échantillonnage instantané

peuvent être très bien adaptés pour suivre les changements rapides de l’environnement de combustion

et ils fourniront un suivi représentatif des concentrations. Cependant, il arrive souvent que les limites

minimales de détection des espèces chimiques présentant un intérêt exigent de plus grands volumes

d’échantillons que ceux obtenus en utilisant ces techniques. Si cette limitation analytique existe,

l’échantillonnage doit être fait sur une période de temps plus longue. Bien que l’utilisation de plus longues

périodes d’échantillonnage permette l’analyse à des concentrations inférieures, cette approche comporte

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certaines limitations. Par exemple, ces types d’échantillonnage permettent uniquement la détermination

de la concentration moyenne intégrée, obtenue au cours de la période d’échantillonnage, mais ils ne

rendent pas compte des changements brusques de concentration des espèces présentant un intérêt.

Cependant, des changements brusques de concentration peuvent également être indétectables avec les

échantillons obtenus par prélèvement instantané, s’ils ne sont pas prélevés suffisamment fréquemment.

Quand les modes opératoires d’échantillonnage en lots sont employés, il est important de spécifier

la fréquence d’échantillonnage, l’heure d’échantillonnage de chaque échantillon et le temps total du

prélèvement. Ces informations sont essentielles afin d’assurer une bonne évaluation des données en

conjonction avec les autres propriétés du feu, qui peuvent être surveillées (par exemple le dégagement

de chaleur, les températures, la perte de masse, l’évolution de la fumée, la propagation des flammes).

Les essais au feu peuvent être classés comme « petit » (taille à l’échelle du laboratoire ou de la paillasse),

« intermédiaire » ou « grand » (en général, grandeur nature). Les gaz prélevés peuvent être soit chauds, soit

proches de la température ambiante. Les gaz doivent généralement être extraits à partir de l’atmosphère

d’essai au travers de tuyaux dédiés à cet effet, à l’aide d’une pompe à aspiration. Les tuyaux en acier

inoxydable, aussi courts que possible, sont souvent utilisés. Dans le cas de production de gaz chauds,

la ligne d’échantillonnage doit être chauffée à une température d’au moins 100 °C. Plusieurs méthodes

analytiques exigent un échantillon séché et débarrassé de toutes les particules. La laine de verre peut

être utilisée (dans la plupart des cas) comme filtre de particules, avec un autre piège constitué d’un agent

déshydratant (par exemple le sulfate de calcium ou le chlorure de calcium), afin d’éliminer l’humidité. Il

convient que les pièges soient situés juste avant l’analyseur et après toutes les sections de chauffage des

tubes d’échantillonnage. Les pièges à refroidissement simples sont souvent insuffisants pour éliminer

les quantités d’humidité présentes dans les effluents du feu; cependant, ils peuvent être utiles s’ils sont

placés en conjonction avec d’autres filtres et d’autres pièges. La technique d’échantillonnage ainsi que

le système analytique employés dicteront les exigences de débit et le besoin d’éliminer l’humidité. Il

convient que des précautions soient prises pour minimiser le volume des systèmes de filtrage, afin de

réduire le temps d’échantillonnage.

À l’exception du fluorure d’hydrogène (HF), les gaz acides doivent être prélevés en utilisant des tubes en

verre, des tubes revêtus d’époxy ou des tubes en PTFE, afin de minimiser les pertes dues à la réactivité

et à la condensation sur la surface des tubes. Pour le fluorure d’hydrogène, des tubes revêtus de PTFE

doivent être utilisés (les tubes en verre et revêtus de verre ne conviennent pas). Pour ces espèces qui

sont relativement réactives et qui sont sujettes aux pertes, les lignes d’échantillonnage doivent être

aussi courtes que possible et doivent être chauffées à une température suffisante pour éviter toute

condensation. Le chlorure d’hydrogène (HCl) et le bromure d’hydrogène (HBr) peuvent être adsorbés sur

des particules de suie aussi bien que sur les lignes d’échantillonnage de gaz (incluant les tubes en PTFE).

Pour les matériaux organiques (par exemple l’acroléine), les tuyaux en acier inoxydable sans revêtement

conviennent, mais les lignes d’échantillonnage doivent être chauffées afin d’éviter toute condensation.

Les pièges à particules, bien qu’habituellement nécessaires, peuvent être évités dans certains cas et il

convient de vérifier les exigences de l’instrument à cet égard.

La localisation et la taille des sondes d’échantillonnage sont régies par la taille de l’appareillage d’essai

et les exigences du système analytique. Cependant, le positionnement des sondes d’échantillonnage pour

les appareils spécifiques est au-delà du domaine d’application de la présente Norme internationale. En

général, la possibilité de stratification des gaz dans les chambres, sans mélange effectif, doit être prise

en compte et il convient d’éviter l’échantillonnage au voisinage des parois de la chambre d’essai.

L’étalonnage du système complet d’échantillonnage et d’analyse, plutôt que juste celui du système

d’analyse, est recommandé, afin de s’assurer que toutes les pertes sur le parcours de l’échantillon sont

prises en compte. Il convient que tous les étalonnages tiennent donc compte des facteurs tels que la

fuite du gaz (dans et hors des lignes d’échantillonnage) et l’adsorption des gaz sur les sondes, les lignes

d’échantillonnage, les filtres et les autres composants. Les gaz d’étalonnage sont souvent obtenus en

bouteilles. Cependant, il est recommandé de vérifier la concentration indiquée par le fournisseur par une

analyse indépendante. Cela est particulièrement vrai pour les gaz réactifs tels que HCl et HF, qui peuvent

se décomposer sur des périodes de temps relativement courtes, même dans une bouteille fermée. Le gaz

d’étalonnage doit être introduit au niveau de la sonde d’échantillonnage et doit parcourir le même trajet

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que le gaz d’essai, à travers les filtres et les pièges, s’ils sont présents, jusqu’au système d’analyse ou au

milieu d’échantillonnage.
4.4 Échantillonnage en utilisant des solutions d’absorption de gaz

Les absorptions de gaz en solution par l’utilisation de bouteilles de lavage de gaz, de tubes de barbotage,

de flacons laveurs, etc., se basent toutes sur le même principe. L’atmosphère d’essai est aspirée ou poussée

à travers le milieu absorbant à une vitesse mesurée pendant une période de temps spécifiée. À la fin de la

période d’échantillonnage, la solution est analysée pour les espèces présentant un intérêt (par exemple

l’ion chlorure pour l’absorption d’acide chlorhydrique gazeux dans l’eau). En admettant une efficacité

de 100 % (voir la discussion ci-après), il est possible de calculer la concentration des espèces en phase

gazeuse, comme étant celle mesurée en solution. Une équation typique de calcul des concentrations est

donnée par l’Équation (1):
ÁV×× mm/
SG S
Á = (1)
q×t
ρ est la concentration en gaz;
ρ est la concentration de la solution;
V est le volume de la solution, exprimé en litres;

m /m est le rapport de la masse atomique ou de la masse moléculaire pour les espèces en phase

G S

gazeuse, G, et les espèces en phase liquide, S, si différentes, par exemple HCl/Cl);

q est le débit du courant de gaz traversant le flacon laveur, exprimé en litres par minute;

t est la durée du débit de gaz, exprimé en minutes.

La fraction volumique du gaz, X , peut être calculée en divisant la concentration par la masse volumique,

d, du gaz dans les conditions ambiantes de température et de pression. Si le gaz peut être assimilé à un

gaz parfait, la masse volumique peut être calculée, comme suit:
d = (2)
XÁ= (3)
M est la masse molaire des espèces en phase gazeuse, g;

H est le volume de gaz occupé par 1 mole de gaz parfait dans les conditions ambiantes de tempé-

rature (T) et de pression (P) appropriées. [H = 8,314 J.K-1.mol-1 × 1 mol × T/P].

- −3

EXEMPLE Si la concentration en ion chlorure (Cl ) de la solution mesurée était de 0,006 g × dm da

...

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