Ambient air - Determination of asbestos fibres - Direct transfer transmission electron microscopy method

This document specifies a reference method using transmission electron microscopy for the determination of airborne asbestos fibres and structures in in a wide range of ambient air situations, including the interior atmospheres of buildings, and for a detailed evaluation for asbestos structures in any atmosphere. The method allows determination of the type(s) of asbestos fibres present and also includes measurement of the lengths, widths and aspect ratios of the asbestos structures. The method cannot discriminate between individual fibres of asbestos and elongate fragments (cleavage fragments and acicular particles) from non-asbestos analogues of the same amphibole mineral.

Air ambiant - Dosage des fibres d'amiante - Méthode par microscopie électronique à transmission par transfert direct

Le pr�sent document sp�cifie une m�thode de r�f�rence utilisant la microscopie �lectronique � transmission pour d�terminer la concentration en fibres et structures d'amiante en suspension dans l'air dans diverses atmosph�res ambiantes, notamment les atmosph�res int�rieures de b�timents, et pour �valuer en d�tail les structures d'amiante dans les atmosph�res. Cette m�thode permet de d�terminer le(s) type(s) de fibres d'amiante pr�sentes et comprend �galement le mesurage des longueurs, des largeurs et des rapports longueur/largeur des structures d'amiante. Elle ne peut pas faire la diff�rence entre des fibres individuelles d'amiante et des fragments allong�s (fragments de clivage et particules aciculaires) d'analogues non asbestiformes du m�me min�ral amphibole[13].

Zunanji zrak - Določevanje azbestnih vlaken - Metoda transmisijske elektronske mikroskopije z neposrednim prenosom

Ta dokument določa referenčno metodo, pri kateri se s prenosno elektronsko mikroskopijo določajo azbestna vlakna in strukture v zraku v najrazličnejših okoliščinah zunanjega zraka, vključno z notranjo atmosfero stavb, ter za podrobno oceno azbestnih struktur v poljubni atmosferi. Metoda omogoča določevanje vrst(-e) prisotnih azbestnih vlaken in vključuje tudi merjenje dolžin, širin in razmerja azbestnih struktur. Z metodo ni mogoče razlikovati med posameznimi vlakni azbesta in razteznimi fragmenti (delci cepitve in acikularnimi delci) iz neazbestnih analogov istega amfibolovega minerala.

General Information

Status
Published
Public Enquiry End Date
09-Oct-2018
Publication Date
10-Nov-2019
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
04-Nov-2019
Due Date
09-Jan-2020
Completion Date
11-Nov-2019

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INTERNATIONAL ISO
STANDARD 10312
Second edition
2019-10
Ambient air — Determination of
asbestos fibres — Direct transfer
transmission electron microscopy
method
Air ambiant — Dosage des fibres d'amiante — Méthode par
microscopie électronique à transmission par transfert direct
Reference number
ISO 10312:2019(E)
ISO 2019
---------------------- Page: 1 ----------------------
ISO 10312:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 10312:2019(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

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

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

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

4 Symbols and abbreviated terms ........................................................................................................................................................... 5

5 Type of sample ........................................................................................................................................................................................................ 6

6 Range ................................................................................................................................................................................................................................ 6

7 Limit of detection ................................................................................................................................................................................................. 6

8 Principle ........................................................................................................................................................................................................................ 7

9 Reagents ........................................................................................................................................................................................................................ 7

10 Apparatus ..................................................................................................................................................................................................................... 8

10.1 Air sampling — Equipment and consumable supplies ........................................................................................ 8

10.1.1 Filter cassette ...................................................................................................................................................................... 8

10.1.2 Sampling pump ................................................................................................................................................................. 8

10.1.3 Stand ........................................................................................................................................................................................... 8

10.1.4 Personal sampling .......................................................................................................................................................... 8

10.1.5 Flowmeter ............................................................................................................................................................................. 8

10.2 Specimen preparation laboratory .......................................................................................................................................... 9

10.3 Equipment for analysis .................................................................................................................................................................... 9

10.3.1 Transmission electron microscope .................................................................................................................. 9

10.3.2 Energy dispersive X-ray analyser ...................................................................................................................11

10.3.3 Plasma asher ....................................................................................................................................................................11

10.3.4 Vacuum coating unit ..................................................................................................................................................11

10.3.5 Sputter coater ..................................................................................................................................................................11

10.3.6 Solvent washer (Jaffe washer) ..........................................................................................................................11

10.3.7 Condensation washer ...............................................................................................................................................12

10.3.8 Slide warmer or oven ................................................................................................................................................13

10.3.9 Ultrasonic bath ...............................................................................................................................................................13

10.3.10 Carbon grating replica..............................................................................................................................................13

10.3.11 Calibration specimen grids for EDXA ..........................................................................................................13

10.3.12 Carbon rod sharpener ..............................................................................................................................................14

10.3.13 Disposable tip micropipettes .............................................................................................................................14

10.4 Consumable supplies ......................................................................................................................................................................14

10.4.1 Copper or nickel electron microscope grids .........................................................................................14

10.4.2 Gold or nickel electron microscope grids ................................................................................................14

10.4.3 Carbon rod electrodes ..............................................................................................................................................14

10.4.4 Routine electron microscopy tools and supplies ..............................................................................14

10.4.5 Reference asbestos samples .................. ..............................................................................................................14

10.4.6 Reference samples of mineral fibres other than asbestos ........................................................15

11 Air sample collection ....................................................................................................................................................................................15

12 Procedure for analysis .................................................................................................................................................................................16

12.1 General ........................................................................................................................................................................................................16

12.2 Cleaning of sample cassettes ...................................................................................................................................................16

12.3 Direct preparation of TEM specimens from polycarbonate filters .........................................................17

12.3.1 Selection of filter area for carbon coating ...............................................................................................17

12.3.2 Carbon coating of filter portions .....................................................................................................................17

12.3.3 Preparation of the Jaffe washer ........................................................................................................................17

12.3.4 Placing of specimens in the Jaffe washer .................................................................................................17

© ISO 2019 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 10312:2019(E)

12.4 Direct preparation of TEM specimens from cellulose ester filters .........................................................18

12.4.1 Selection of area of filter for preparation ................................................................................................18

12.4.2 Preparation of solution for collapsing cellulose ester filters ..................................................18

12.4.3 Filter collapsing procedure ..................................................................................................................................18

12.4.4 Plasma etching of the filter surfaces ............................................................................................................18

12.4.5 Carbon coating ................................................................................................................................................................18

12.4.6 Preparation of the Jaffe washer ........................................................................................................................18

12.4.7 Placing of specimens in the Jaffe washer .................................................................................................18

12.5 Criteria for acceptable TEM specimen grids ..............................................................................................................19

12.6 Procedure for structure counting by TEM....................................................................................................................19

12.6.1 General...................................................................................................................................................................................19

12.6.2 Measurement of mean opening area ...........................................................................................................20

12.6.3 TEM alignment and calibration procedures ..........................................................................................20

12.6.4 Determination of criterion for termination of TEM examination.......................................20

12.6.5 General procedure for structure counting and size analysis ..................................................21

12.6.6 Magnification requirements ...............................................................................................................................23

12.7 Blank and quality control determinations ...................................................................................................................24

12.8 Calculation of results ......................................................................................................................................................................24

13 Performance characteristics .................................................................................................................................................................25

13.1 General ........................................................................................................................................................................................................25

13.2 Interferences and limitations of fibre identification ...........................................................................................25

13.3 Precision and accuracy..................................................................................................................................................................25

13.3.1 Precision...............................................................................................................................................................................25

13.3.2 Accuracy ...............................................................................................................................................................................26

13.3.3 Inter-laboratory and intra-laboratory analyses .................................................................................26

13.4 Limit of detection ...............................................................................................................................................................................26

14 Test report ................................................................................................................................................................................................................27

Annex A (normative) Determination of operating conditions for plasma asher ................................................30

Annex B (normative) Calibration procedures..........................................................................................................................................31

Annex C (normative) Structure counting criteria ................................................................................................................................34

Annex D (normative) Fibre identification procedure ......................................................................................................................44

Annex E (normative) Determination of the concentration of asbestos fibres and bundles

longer than 5 µm, and PCM equivalent asbestos fibres .............................................................................................61

Annex F (normative) Calculation of results ................................................................................................................................................62

Annex G (informative) Strategies for collection of air samples .............................................................................................68

Annex H (informative) Methods for removal of gypsum fibres ..............................................................................................69

Bibliography .............................................................................................................................................................................................................................70

iv © ISO 2019 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 10312:2019(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 146, Air quality, Subcommittee SC 3,

Ambient atmospheres.

This second edition cancels and replaces the first edition (ISO 10312:1995), which has been technically

revised. The main changes compared to the previous edition are as follows:
— the use of electronic display systems with measurement software is permitted;

— the maximum particulate loading for TEM specimens is increased from 10 % to 25 %;

— a simplified fibre identification procedure for investigation of known sources of the regulated

asbestos varieties and richterite/winchite asbestos is permitted;

— the reporting requirements have been changed to permit reporting of the concentrations of fibres

and bundles longer than 5 µm and/or the concentrations of PCM equivalent fibres without the

requirement to report the concentrations of structures equal to or greater than 0,5 µm;

— there is no requirement to report the 95% confidence intervals of the fibre concentrations.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2019 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO 10312:2019(E)
Introduction

This document is applicable to the determination of airborne asbestos in a wide range of ambient

air situations, including the interior atmospheres of buildings, and for a detailed evaluation of

any atmosphere. Because the best available medical evidence indicates that the numerical fibre

concentration and the fibre sizes are the relevant parameters for evaluation of the inhalation hazards,

a fibre counting technique is the only logical approach. Most fibres in ambient atmospheres are not

asbestos and therefore, there is a requirement for fibres to be identified. Many airborne asbestos

fibres in ambient atmospheres have diameters below the resolution limit of the optical microscope.

This document is based on transmission electron microscopy, which has adequate resolution to allow

detection of small fibres and is currently the only technique capable of unequivocal identification of

the majority of individual fibres of asbestos. Airborne asbestos is often found as a mixture of single

fibres and more complex, aggregated structures which may or may not be also aggregated with other

particles. The fibres found suspended in an ambient atmosphere can often be identified unequivocally,

if a sufficient measurement effort is expended. However, if each fibre were to be identified in this way,

the analysis would become prohibitively expensive. Because of instrumental deficiencies or because

of the nature of the particulate, some fibres cannot be positively identified as asbestos, even though

the measurements all indicate that they could be asbestos. Subjective factors therefore contribute

to this measurement, and consequently a very precise definition of the procedure for identification

and enumeration of, asbestos fibres is required. The method specified in this document is designed

to provide the best description possible of the nature, numerical concentration, and sizes of asbestos-

containing particles found in an air sample. This document requires that a very detailed and logical

procedure be used to reduce the subjective aspects of the measurement. The method of data recording

specified in this document is designed to allow re-evaluation of the structure counting data as new

medical evidence becomes available. All feasible specimen preparation techniques result in some

modification of the airborne particulate. Even the collection of particles from a three-dimensional

airborne dispersion onto a two-dimensional filter surface can be considered a modification of the

particulate, and some of the particles in most samples are modified by the specimen preparation

procedures. However, the procedures specified in this document are designed to minimize the

disturbance of the collected particulate material, and the effect of those disturbances that do occur can

be evaluated.

This document describes the method of analysis for a single air filter. However, one of the largest

potential errors in characterizing asbestos in ambient atmospheres is associated with the variability

between filter samples. For this reason, it is necessary to design a replicate sampling scheme in order to

determine this document’s accuracy and precision.
vi © ISO 2019 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 10312:2019(E)
Ambient air — Determination of asbestos fibres — Direct
transfer transmission electron microscopy method
1 Scope

This document specifies a reference method using transmission electron microscopy for the

determination of airborne asbestos fibres and structures in in a wide range of ambient air situations,

including the interior atmospheres of buildings, and for a detailed evaluation for asbestos structures

in any atmosphere. The method allows determination of the type(s) of asbestos fibres present and also

includes measurement of the lengths, widths and aspect ratios of the asbestos structures. The method

cannot discriminate between individual fibres of asbestos and elongate fragments (cleavage fragments

[13]

and acicular particles) from non-asbestos analogues of the same amphibole mineral .

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 4225, Air quality — General aspects — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 4225 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
acicular

shape shown by an extremely slender crystal with cross-sectional dimensions, which are small relative

to its length, i.e. needle-like
3.2
amphibole

group of rock-forming ferromagnesium silicate minerals, closely related in crystal form and

composition, and having the nominal formula:
A B C T O (OH,F,Cl)
0-1 2 5 8 22 2
where
A = K, Na;
B = Fe , Mn, Mg, Ca, Na;
3+ 2+
C = Al, Cr, Ti, Fe , Mg, Fe ;
T = Si, Al, Cr, Fe , Ti.
© ISO 2019 – All rights reserved 1
---------------------- Page: 7 ----------------------
ISO 10312:2019(E)

Note 1 to entry: In some varieties of amphibole, these elements can be partially substituted by Li, Pb, or Zn.

Amphibole is characterized by a cross-linked double chain of Si-O tetrahedra with a silicon: oxygen ratio of 4:11,

by columnar or fibrous prismatic crystals and by good prismatic cleavage in two directions parallel to the crystal

faces and intersecting at angles of about 56° and 124°.
3.3
amphibole asbestos
amphibole (3.2) in an asbestiform (3.5) habit
3.4
analytical sensitivity

calculated airborne asbestos structure (3.7) concentration in structures/litre, equivalent to counting of

one asbestos (3.6) structure in the analysis
Note 1 to entry: It is expressed in structures/litre.

Note 2 to entry: This method does not specify a unique analytical sensitivity. The analytical sensitivity is

determined by the needs of the measurement and the conditions found on the prepared sample.

3.5
asbestiform

specific type of mineral fibrosity in which the fibres (3.22) and fibrils possess high tensile strength and

flexibility
3.6
asbestos

group of silicate minerals belonging to the serpentine and amphibole (3.2) groups, which have

crystallized in the asbestiform habit, causing them to be easily separated into long, thin, flexible, strong

fibres (3.22) when crushed or processed

Note 1 to entry: The Chemical Abstracts Service Registry Numbers of the most common asbestos varieties are:

chrysotile (12001-29-5), crocidolite (12001-28-4), grunerite asbestos (Amosite) (12172-73-5), anthophyllite

asbestos (77536-67-5), tremolite asbestos (77536-68-6) and actinolite asbestos (77536-66-4). Other varieties of

[19]

asbestiform amphibole, such as richterite asbestos and winchite asbestos may also be found in some products

such as vermiculite and talc.
3.7
asbestos structure

individual fibre (3.22), or any connected or overlapping grouping of asbestos (3.6) fibres or bundles,

with or without other particles
3.8
aspect ratio
ratio of length to width of a particle
3.9
blank

structure count made on transmission electron microscope specimens prepared from an unused filter,

to determine the background measurement
3.10
camera length

equivalent projection length between the specimen and its electron diffraction pattern, in the absence

of lens action
3.11
chrysotile

fibrous mineral of the serpentine group, which has the nominal composition: Mg Si O (OH)

3 2 5 4

Note 1 to entry: Most natural chrysotile deviates little from this nominal composition. In some varieties of

3+ 3+ 2+ 3+

chrysotile, minor substitution of silicon by Al may occur. Minor substitution of magnesium by Al , Fe , Fe ,

2+ 2+ 2+

Ni , Mn and Co may also be present. Chrysotile is the most prevalent type of asbestos.

2 © ISO 2019 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 10312:2019(E)
3.12
cleavage
breaking of a mineral along one of its crystallographic directions
3.13
cleavage fragment
fragment of a crystal that is bounded by cleavage (3.12) faces

Note 1 to entry: Crushing of non-asbestiform amphibole generally yields elongated fragments that conform to

the definition of a fibre.
3.14
cluster

structure in which two or more fibres (3.22), or fibre bundles (3.23), are randomly oriented in a

connected grouping
3.15
d-spacing
distance between identical adjacent and parallel planes of atoms in a crystal
3.16
electron diffraction

technique in electron microscopy by which the crystal structure of a specimen is examined

3.17
electron scattering power

extent to which a thin layer of substance scatters electrons from their original directions

3.18
energy dispersive X-ray analysis
EDXA

measurement of the energies and intensities of X-rays by use of a solid-state detector and multi-channel

analyser system
3.19
eucentric

condition when the area of interest of an object is placed on a tilting axis at the intersection of the

electron beam with that axis and is in the plane of focus
3.20
field blank
filter cassette that has been taken to the sampling site, opened and then closed

Note 1 to entry: Such a filter is used to determine the background structure count for the measurement.

3.21
fibril

single fibre (3.22) of asbestos (3.6), which cannot be further separated longitudinally into smaller

components without losing its fibrous properties or appearances
3.22
fibre
elongated particle that has parallel or stepped sides

Note 1 to entry: For the purposes of this document, a fibre is defined to have an aspect ratio equal to or greater

than 5:1 and a minimum length of 0,5 μm.
© ISO 2019 – All rights reserved 3
---------------------- Page: 9 ----------------------
ISO 10312:2019(E)
3.23
fibre bundle
structure composed of parallel, smaller diameter fibres (3.22) attached
...

SLOVENSKI STANDARD
SIST ISO 10312:2019
01-december-2019
Nadomešča:
SIST ISO 10312:1996
Zunanji zrak - Določevanje azbestnih vlaken - Metoda transmisijske elektronske
mikroskopije z neposrednim prenosom

Ambient air - Determination of asbestos fibres - Direct transfer transmission electron

microscopy method

Air ambiant - Dosage des fibres d'amiante - Méthode par microscopie électronique à

transmission par transfert direct
Ta slovenski standard je istoveten z: ISO 10312:2019
ICS:
13.040.20 Kakovost okoljskega zraka Ambient atmospheres
SIST ISO 10312:2019 en

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

---------------------- Page: 1 ----------------------
SIST ISO 10312:2019
---------------------- Page: 2 ----------------------
SIST ISO 10312:2019
INTERNATIONAL ISO
STANDARD 10312
Second edition
2019-10
Ambient air — Determination of
asbestos fibres — Direct transfer
transmission electron microscopy
method
Air ambiant — Dosage des fibres d'amiante — Méthode par
microscopie électronique à transmission par transfert direct
Reference number
ISO 10312:2019(E)
ISO 2019
---------------------- Page: 3 ----------------------
SIST ISO 10312:2019
ISO 10312:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 10312:2019
ISO 10312:2019(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

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

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

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

4 Symbols and abbreviated terms ........................................................................................................................................................... 5

5 Type of sample ........................................................................................................................................................................................................ 6

6 Range ................................................................................................................................................................................................................................ 6

7 Limit of detection ................................................................................................................................................................................................. 6

8 Principle ........................................................................................................................................................................................................................ 7

9 Reagents ........................................................................................................................................................................................................................ 7

10 Apparatus ..................................................................................................................................................................................................................... 8

10.1 Air sampling — Equipment and consumable supplies ........................................................................................ 8

10.1.1 Filter cassette ...................................................................................................................................................................... 8

10.1.2 Sampling pump ................................................................................................................................................................. 8

10.1.3 Stand ........................................................................................................................................................................................... 8

10.1.4 Personal sampling .......................................................................................................................................................... 8

10.1.5 Flowmeter ............................................................................................................................................................................. 8

10.2 Specimen preparation laboratory .......................................................................................................................................... 9

10.3 Equipment for analysis .................................................................................................................................................................... 9

10.3.1 Transmission electron microscope .................................................................................................................. 9

10.3.2 Energy dispersive X-ray analyser ...................................................................................................................11

10.3.3 Plasma asher ....................................................................................................................................................................11

10.3.4 Vacuum coating unit ..................................................................................................................................................11

10.3.5 Sputter coater ..................................................................................................................................................................11

10.3.6 Solvent washer (Jaffe washer) ..........................................................................................................................11

10.3.7 Condensation washer ...............................................................................................................................................12

10.3.8 Slide warmer or oven ................................................................................................................................................13

10.3.9 Ultrasonic bath ...............................................................................................................................................................13

10.3.10 Carbon grating replica..............................................................................................................................................13

10.3.11 Calibration specimen grids for EDXA ..........................................................................................................13

10.3.12 Carbon rod sharpener ..............................................................................................................................................14

10.3.13 Disposable tip micropipettes .............................................................................................................................14

10.4 Consumable supplies ......................................................................................................................................................................14

10.4.1 Copper or nickel electron microscope grids .........................................................................................14

10.4.2 Gold or nickel electron microscope grids ................................................................................................14

10.4.3 Carbon rod electrodes ..............................................................................................................................................14

10.4.4 Routine electron microscopy tools and supplies ..............................................................................14

10.4.5 Reference asbestos samples .................. ..............................................................................................................14

10.4.6 Reference samples of mineral fibres other than asbestos ........................................................15

11 Air sample collection ....................................................................................................................................................................................15

12 Procedure for analysis .................................................................................................................................................................................16

12.1 General ........................................................................................................................................................................................................16

12.2 Cleaning of sample cassettes ...................................................................................................................................................16

12.3 Direct preparation of TEM specimens from polycarbonate filters .........................................................17

12.3.1 Selection of filter area for carbon coating ...............................................................................................17

12.3.2 Carbon coating of filter portions .....................................................................................................................17

12.3.3 Preparation of the Jaffe washer ........................................................................................................................17

12.3.4 Placing of specimens in the Jaffe washer .................................................................................................17

© ISO 2019 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 10312:2019
ISO 10312:2019(E)

12.4 Direct preparation of TEM specimens from cellulose ester filters .........................................................18

12.4.1 Selection of area of filter for preparation ................................................................................................18

12.4.2 Preparation of solution for collapsing cellulose ester filters ..................................................18

12.4.3 Filter collapsing procedure ..................................................................................................................................18

12.4.4 Plasma etching of the filter surfaces ............................................................................................................18

12.4.5 Carbon coating ................................................................................................................................................................18

12.4.6 Preparation of the Jaffe washer ........................................................................................................................18

12.4.7 Placing of specimens in the Jaffe washer .................................................................................................18

12.5 Criteria for acceptable TEM specimen grids ..............................................................................................................19

12.6 Procedure for structure counting by TEM....................................................................................................................19

12.6.1 General...................................................................................................................................................................................19

12.6.2 Measurement of mean opening area ...........................................................................................................20

12.6.3 TEM alignment and calibration procedures ..........................................................................................20

12.6.4 Determination of criterion for termination of TEM examination.......................................20

12.6.5 General procedure for structure counting and size analysis ..................................................21

12.6.6 Magnification requirements ...............................................................................................................................23

12.7 Blank and quality control determinations ...................................................................................................................24

12.8 Calculation of results ......................................................................................................................................................................24

13 Performance characteristics .................................................................................................................................................................25

13.1 General ........................................................................................................................................................................................................25

13.2 Interferences and limitations of fibre identification ...........................................................................................25

13.3 Precision and accuracy..................................................................................................................................................................25

13.3.1 Precision...............................................................................................................................................................................25

13.3.2 Accuracy ...............................................................................................................................................................................26

13.3.3 Inter-laboratory and intra-laboratory analyses .................................................................................26

13.4 Limit of detection ...............................................................................................................................................................................26

14 Test report ................................................................................................................................................................................................................27

Annex A (normative) Determination of operating conditions for plasma asher ................................................30

Annex B (normative) Calibration procedures..........................................................................................................................................31

Annex C (normative) Structure counting criteria ................................................................................................................................34

Annex D (normative) Fibre identification procedure ......................................................................................................................44

Annex E (normative) Determination of the concentration of asbestos fibres and bundles

longer than 5 µm, and PCM equivalent asbestos fibres .............................................................................................61

Annex F (normative) Calculation of results ................................................................................................................................................62

Annex G (informative) Strategies for collection of air samples .............................................................................................68

Annex H (informative) Methods for removal of gypsum fibres ..............................................................................................69

Bibliography .............................................................................................................................................................................................................................70

iv © ISO 2019 – All rights reserved
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SIST ISO 10312:2019
ISO 10312:2019(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 146, Air quality, Subcommittee SC 3,

Ambient atmospheres.

This second edition cancels and replaces the first edition (ISO 10312:1995), which has been technically

revised. The main changes compared to the previous edition are as follows:
— the use of electronic display systems with measurement software is permitted;

— the maximum particulate loading for TEM specimens is increased from 10 % to 25 %;

— a simplified fibre identification procedure for investigation of known sources of the regulated

asbestos varieties and richterite/winchite asbestos is permitted;

— the reporting requirements have been changed to permit reporting of the concentrations of fibres

and bundles longer than 5 µm and/or the concentrations of PCM equivalent fibres without the

requirement to report the concentrations of structures equal to or greater than 0,5 µm;

— there is no requirement to report the 95% confidence intervals of the fibre concentrations.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2019 – All rights reserved v
---------------------- Page: 7 ----------------------
SIST ISO 10312:2019
ISO 10312:2019(E)
Introduction

This document is applicable to the determination of airborne asbestos in a wide range of ambient

air situations, including the interior atmospheres of buildings, and for a detailed evaluation of

any atmosphere. Because the best available medical evidence indicates that the numerical fibre

concentration and the fibre sizes are the relevant parameters for evaluation of the inhalation hazards,

a fibre counting technique is the only logical approach. Most fibres in ambient atmospheres are not

asbestos and therefore, there is a requirement for fibres to be identified. Many airborne asbestos

fibres in ambient atmospheres have diameters below the resolution limit of the optical microscope.

This document is based on transmission electron microscopy, which has adequate resolution to allow

detection of small fibres and is currently the only technique capable of unequivocal identification of

the majority of individual fibres of asbestos. Airborne asbestos is often found as a mixture of single

fibres and more complex, aggregated structures which may or may not be also aggregated with other

particles. The fibres found suspended in an ambient atmosphere can often be identified unequivocally,

if a sufficient measurement effort is expended. However, if each fibre were to be identified in this way,

the analysis would become prohibitively expensive. Because of instrumental deficiencies or because

of the nature of the particulate, some fibres cannot be positively identified as asbestos, even though

the measurements all indicate that they could be asbestos. Subjective factors therefore contribute

to this measurement, and consequently a very precise definition of the procedure for identification

and enumeration of, asbestos fibres is required. The method specified in this document is designed

to provide the best description possible of the nature, numerical concentration, and sizes of asbestos-

containing particles found in an air sample. This document requires that a very detailed and logical

procedure be used to reduce the subjective aspects of the measurement. The method of data recording

specified in this document is designed to allow re-evaluation of the structure counting data as new

medical evidence becomes available. All feasible specimen preparation techniques result in some

modification of the airborne particulate. Even the collection of particles from a three-dimensional

airborne dispersion onto a two-dimensional filter surface can be considered a modification of the

particulate, and some of the particles in most samples are modified by the specimen preparation

procedures. However, the procedures specified in this document are designed to minimize the

disturbance of the collected particulate material, and the effect of those disturbances that do occur can

be evaluated.

This document describes the method of analysis for a single air filter. However, one of the largest

potential errors in characterizing asbestos in ambient atmospheres is associated with the variability

between filter samples. For this reason, it is necessary to design a replicate sampling scheme in order to

determine this document’s accuracy and precision.
vi © ISO 2019 – All rights reserved
---------------------- Page: 8 ----------------------
SIST ISO 10312:2019
INTERNATIONAL STANDARD ISO 10312:2019(E)
Ambient air — Determination of asbestos fibres — Direct
transfer transmission electron microscopy method
1 Scope

This document specifies a reference method using transmission electron microscopy for the

determination of airborne asbestos fibres and structures in in a wide range of ambient air situations,

including the interior atmospheres of buildings, and for a detailed evaluation for asbestos structures

in any atmosphere. The method allows determination of the type(s) of asbestos fibres present and also

includes measurement of the lengths, widths and aspect ratios of the asbestos structures. The method

cannot discriminate between individual fibres of asbestos and elongate fragments (cleavage fragments

[13]

and acicular particles) from non-asbestos analogues of the same amphibole mineral .

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 4225, Air quality — General aspects — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 4225 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
acicular

shape shown by an extremely slender crystal with cross-sectional dimensions, which are small relative

to its length, i.e. needle-like
3.2
amphibole

group of rock-forming ferromagnesium silicate minerals, closely related in crystal form and

composition, and having the nominal formula:
A B C T O (OH,F,Cl)
0-1 2 5 8 22 2
where
A = K, Na;
B = Fe , Mn, Mg, Ca, Na;
3+ 2+
C = Al, Cr, Ti, Fe , Mg, Fe ;
T = Si, Al, Cr, Fe , Ti.
© ISO 2019 – All rights reserved 1
---------------------- Page: 9 ----------------------
SIST ISO 10312:2019
ISO 10312:2019(E)

Note 1 to entry: In some varieties of amphibole, these elements can be partially substituted by Li, Pb, or Zn.

Amphibole is characterized by a cross-linked double chain of Si-O tetrahedra with a silicon: oxygen ratio of 4:11,

by columnar or fibrous prismatic crystals and by good prismatic cleavage in two directions parallel to the crystal

faces and intersecting at angles of about 56° and 124°.
3.3
amphibole asbestos
amphibole (3.2) in an asbestiform (3.5) habit
3.4
analytical sensitivity

calculated airborne asbestos structure (3.7) concentration in structures/litre, equivalent to counting of

one asbestos (3.6) structure in the analysis
Note 1 to entry: It is expressed in structures/litre.

Note 2 to entry: This method does not specify a unique analytical sensitivity. The analytical sensitivity is

determined by the needs of the measurement and the conditions found on the prepared sample.

3.5
asbestiform

specific type of mineral fibrosity in which the fibres (3.22) and fibrils possess high tensile strength and

flexibility
3.6
asbestos

group of silicate minerals belonging to the serpentine and amphibole (3.2) groups, which have

crystallized in the asbestiform habit, causing them to be easily separated into long, thin, flexible, strong

fibres (3.22) when crushed or processed

Note 1 to entry: The Chemical Abstracts Service Registry Numbers of the most common asbestos varieties are:

chrysotile (12001-29-5), crocidolite (12001-28-4), grunerite asbestos (Amosite) (12172-73-5), anthophyllite

asbestos (77536-67-5), tremolite asbestos (77536-68-6) and actinolite asbestos (77536-66-4). Other varieties of

[19]

asbestiform amphibole, such as richterite asbestos and winchite asbestos may also be found in some products

such as vermiculite and talc.
3.7
asbestos structure

individual fibre (3.22), or any connected or overlapping grouping of asbestos (3.6) fibres or bundles,

with or without other particles
3.8
aspect ratio
ratio of length to width of a particle
3.9
blank

structure count made on transmission electron microscope specimens prepared from an unused filter,

to determine the background measurement
3.10
camera length

equivalent projection length between the specimen and its electron diffraction pattern, in the absence

of lens action
3.11
chrysotile

fibrous mineral of the serpentine group, which has the nominal composition: Mg Si O (OH)

3 2 5 4

Note 1 to entry: Most natural chrysotile deviates little from this nominal composition. In some varieties of

3+ 3+ 2+ 3+

chrysotile, minor substitution of silicon by Al may occur. Minor substitution of magnesium by Al , Fe , Fe ,

2+ 2+ 2+

Ni , Mn and Co may also be present. Chrysotile is the most prevalent type of asbestos.

2 © ISO 2019 – All rights reserved
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SIST ISO 10312:2019
ISO 10312:2019(E)
3.12
cleavage
breaking of a mineral along one of its crystallographic directions
3.13
cleavage fragment
fragment of a crystal that is bounded by cleavage (3.12) faces

Note 1 to entry: Crushing of non-asbestiform amphibole generally yields elongated fragments that conform to

the definition of a fibre.
3.14
cluster

structure in which two or more fibres (3.22), or fibre bundles (3.23), are randomly oriented in a

connected grouping
3.15
d-spacing
distance between identical adjacent and parallel planes of atoms in a crystal
3.16
electron diffraction

technique in electron microscopy by which the crystal structure of a specimen is examined

3.17
electron scattering power

extent to which a thin layer of substance scatters electrons from their original directions

3.18
energy dispersive X-ray analysis
EDXA

measurement of the energies and intensities of X-rays by use of a solid-state detector and multi-channel

analyser s
...

NORME ISO
INTERNATIONALE 10312
Deuxième édition
2019-10
Air ambiant — Dosage des fibres
d'amiante — Méthode par microscopie
électronique à transmission par
transfert direct
Ambient air — Determination of asbestos fibres — Direct transfer
transmission electron microscopy method
Numéro de référence
ISO 10312:2019(F)
ISO 2019
---------------------- Page: 1 ----------------------
ISO 10312:2019(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2019

Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette

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Publié en Suisse
ii © ISO 2019 – Tous droits réservés
---------------------- Page: 2 ----------------------
ISO 10312:2019(F)
Sommaire Page

Avant-propos ................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

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

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

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

4 Symboles et abréviations ............................................................................................................................................................................. 5

5 Type d’échantillon .............................................................................................................................................................................................. 6

6 Plage de mesure .................................................................................................................................................................................................... 6

7 Limite de détection ............................................................................................................................................................................................ 6

8 Principe .......................................................................................................................................................................................................................... 7

9 Réactifs ........................................................................................................................................................................................................................... 8

10 Appareillage .............................................................................................................................................................................................................. 8

10.1 Prélèvement d’air — Équipement et consommables ............................................................................................ 8

10.1.1 Cassette porte-filtre....................................................................................................................................................... 8

10.1.2 Pompe de prélèvement ............................................................................................................................................... 9

10.1.3 Support ..................................................................................................................................................................................... 9

10.1.4 Prélèvement sur individu ......................................................................................................................................... 9

10.1.5 Débitmètre ............................................................................................................................................................................ 9

10.2 Laboratoire de préparation des échantillons ............................................................................................................... 9

10.3 Équipement d’analyse ....................................................................................................................................................................10

10.3.1 Microscope électronique à transmission .................................................................................................10

10.3.2 Analyseur en dispersion d’énergie des rayons X ...............................................................................12

10.3.3 Four à plasma...................................................................................................................................................................12

10.3.4 Évaporateur sous vide ..............................................................................................................................................12

10.3.5 Pulvérisateur cathodique ......................................................................................................................................12

10.3.6 Laveur à solvant (laveur Jaffe) ..........................................................................................................................13

10.3.7 Dissolveur à condensation ...................................................................................................................................13

10.3.8 Plaque chauffante ou étuve ..................................................................................................................................14

10.3.9 Bain à ultrasons .............................................................................................................................................................14

10.3.10 Réplique d’un réseau carbone ...........................................................................................................................14

10.3.11 Grilles MET d’étalonnage pour SDEX ..........................................................................................................14

10.3.12 Aiguiseur d’électrodes en carbone ................................................................................................................15

10.3.13 Micropipettes à embout jetable .......................................................................................................................15

10.4 Consommables .....................................................................................................................................................................................15

10.4.1 Grilles de microscope électronique en cuivre ou en nickel ......................................................15

10.4.2 Grilles de microscope électronique en or ou en nickel ................................................................15

10.4.3 Électrodes en carbone ..............................................................................................................................................15

10.4.4 Outils et fournitures courants pour microscopie électronique ............................................15

10.4.5 Échantillons d’amiante de référence ...........................................................................................................15

10.4.6 Échantillons de référence de fibres minérales autres que l’amiante ...............................16

11 Prélèvement des échantillons d’air ...............................................................................................................................................16

12 Mode opératoire d’analyse ......................................................................................................................................................................17

12.1 Généralités ...............................................................................................................................................................................................17

12.2 Nettoyage des cassettes de prélèvement .......................................................................................................................18

12.3 Préparation directe d’échantillons MET à partir de filtres en polycarbonate ...............................18

12.3.1 Sélection de la surface du filtre pour le dépôt de carbone .......................................................18

12.3.2 Dépôt de carbone sur les parties de filtre ...............................................................................................18

12.3.3 Préparation du laveur Jaffe ..................................................................................................................................18

12.3.4 Mise en place des échantillons dans le laveur Jaffe.........................................................................18

© ISO 2019 – Tous droits réservés iii
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ISO 10312:2019(F)

12.4 Préparation directe d’échantillons MET à partir de filtres en esters de cellulose .....................19

12.4.1 Sélection de la surface du filtre à préparer ............................................................................................19

12.4.2 Préparation de la solution pour réduire les filtres en esters de cellulose ...................19

12.4.3 Mode opératoire pour la réduction du filtre .........................................................................................19

12.4.4 Décapage plasma des surfaces du filtre ....................................................................................................19

12.4.5 Dépôt de carbone .........................................................................................................................................................20

12.4.6 Préparation du laveur Jaffe ..................................................................................................................................20

12.4.7 Mise en place des échantillons dans le laveur Jaffe.........................................................................20

12.5 Critères d’acceptation des grilles d’échantillons MET .......................................................................................20

12.6 Mode opératoire de comptage des structures par MET ...................................................................................21

12.6.1 Généralités .........................................................................................................................................................................21

12.6.2 Mesurage de la surface moyenne d’ouverture ....................................................................................21

12.6.3 Modes opératoires d’alignement et d’étalonnage du MET .......................................................22

12.6.4 Détermination du critère d’arrêt de l’examen au MET ................................................................22

12.6.5 Mode opératoire général de comptage et d’analyse des dimensions des

structures ............................................................................................................................................................................22

12.6.6 Exigences de grossissement ................................................................................................................................25

12.7 Déterminations des blancs et du contrôle qualité .................................................................................................26

12.8 Calcul des résultats ...........................................................................................................................................................................26

13 Caractéristiques de performance ....................................................................................................................................................27

13.1 Généralités ...............................................................................................................................................................................................27

13.2 Interférences et limites à l’identification des fibres ............................................................................................27

13.3 Fidélité et exactitude .......................................................................................................................................................................27

13.3.1 Fidélité ...................................................................................................................................................................................27

13.3.2 Exactitude ...........................................................................................................................................................................28

13.3.3 Analyses inter- et intralaboratoires .............................................................................................................28

13.4 Limite de détection ...........................................................................................................................................................................28

14 Rapport d’essai ....................................................................................................................................................................................................29

Annexe A (normative) Détermination des conditions de fonctionnement du four à plasma ................33

Annexe B (normative) Modes opératoires d’étalonnage ..............................................................................................................34

Annexe C (normative) Critères de comptage des structures ....................................................................................................37

Annexe D (normative) Mode opératoire d’identification des fibres ................................................................................47

Annexe E (normative) Détermination de la concentration en fibres et faisceaux d’amiante

d’une longueur supérieure à 5 µm, et de la concentration en fibres d’amiante

équivalent MOCP ................................................................................................................................................................................................64

Annexe F (normative) Calcul des résultats .................................................................................................................................................65

Annexe G (informative) Stratégies de prélèvement d’échantillons d’air .....................................................................71

Annexe H (informative) Méthodes d’élimination des fibres de gypse ............................................................................72

Bibliographie ...........................................................................................................................................................................................................................73

iv © ISO 2019 – Tous droits réservés
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ISO 10312:2019(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 (IEC) en ce qui

concerne la normalisation électrotechnique.

Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont

décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents

critères d’approbation requis pour les différents types de documents ISO. Le présent document a été

rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir www

.iso .org/ directives).

L’attention est attirée 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. Les détails concernant

les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de

l’élaboration du document sont indiqués dans l’Introduction et/ou dans la liste des déclarations de

brevets reçues par l’ISO (voir www .iso .org/ brevets).

Les appellations commerciales éventuellement mentionnées dans le présent document sont données

pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un

engagement.

Pour une explication de la nature volontaire des normes, la signification des termes et expressions

spécifiques de l’ISO liés à l’évaluation de la conformité, ou pour toute information au sujet de l’adhésion

de l’ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles

techniques au commerce (OTC), voir le lien suivant: www .iso .org/ iso/ fr/ avant -propos.

Le présent document a été élaboré par le comité technique ISO/TC 146, Qualité de l’air, sous-comité SC 3,

Atmosphères ambiantes.

Cette deuxième édition annule et remplace la première édition (ISO 10312:1995), qui a fait l’objet d’une

révision technique. Les principales modifications par rapport à l’édition précédente sont les suivantes:

— l’utilisation de systèmes de visualisation électroniques équipés d’un logiciel de mesure est autorisée;

— la densité de particules maximale pour les échantillons MET est portée de 10 % à 25 %;

— un mode opératoire simplifié d’identification des fibres pour étudier les sources connues des

variétés d’amiante réglementées et d’amiante richtérite/winchite est autorisé;

— les exigences en matière de rapport d’essai ont été modifiées pour permettre de consigner les

concentrations de fibres et de faisceaux de plus de 5 µm de longueur et/ou les concentrations de fibres

équivalent MOCP sans qu’il soit exigé de consigner les concentrations de structures supérieures ou

égales à 0,5 µm;

— il n’est pas exigé de consigner les intervalles de confiance à 95 % des concentrations de fibres.

Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent

document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes

se trouve à l’adresse www .iso .org/ fr/ members .html.
© ISO 2019 – Tous droits réservés v
---------------------- Page: 5 ----------------------
ISO 10312:2019(F)
Introduction

Le présent document est applicable au dosage de l’amiante en suspension dans l’air ambiant dans un

nombre varié de situations, y compris les atmosphères intérieures des bâtiments, et à une évaluation

détaillée de toute atmosphère. Les recherches médicales les plus avancées indiquant que la concentration

numérique des fibres ainsi que leur taille sont les paramètres les plus pertinents pour évaluer les risques

pour la santé liés à l’inhalation, une technique de comptage des fibres constitue la seule approche

logique. La plupart des fibres en suspension dans les atmosphères ambiantes ne sont pas de l’amiante

et, par conséquent, il est nécessaire de les identifier. De nombreuses fibres d’amiante en suspension

dans l’air dans les atmosphères ambiantes ont des diamètres inférieurs à la limite de résolution du

microscope optique. Le présent document est fondé sur la microscopie électronique à transmission, qui

a une résolution adéquate pour permettre la détection de petites fibres et qui est actuellement la seule

technique capable d’identifier sans équivoque la majorité des fibres individuelles d’amiante. L’amiante

en suspension dans l’air se présente souvent sous forme de mélange de fibres individuelles et de

structures agrégées plus complexes qui peuvent également être ou non agrégées à d’autres particules.

Les fibres trouvées en suspension dans une atmosphère ambiante peuvent souvent être identifiées sans

équivoque, si un soin suffisant est apporté à l’analyse. Cependant, si chaque fibre devait être identifiée de

cette manière, le coût de l’analyse deviendrait prohibitif. En raison des insuffisances des instruments ou

de la nature des particules, certaines fibres ne peuvent pas être formellement identifiées comme étant

de l’amiante, même si les mesures indiquent toutes qu’elles pourraient en être. Des facteurs subjectifs

interviennent dans ces mesurages et, par conséquent, une définition très précise du mode opératoire

d’identification et de comptage des fibres d’amiante est nécessaire. La méthode spécifiée dans le présent

document est destinée à fournir la meilleure description possible de la nature, de la concentration

numérique et des tailles des particules contenant de l’amiante trouvées dans un échantillon d’air. Le

présent document exige l’utilisation d’un mode opératoire très détaillé et logique pour réduire les

aspects subjectifs du mesurage. La méthode d’enregistrement des données spécifiée dans le présent

document est destinée à permettre une réévaluation des données de comptage des structures à mesure

que de nouvelles données médicales sont disponibles. Toutes les techniques possibles de préparation

des échantillons entraînent des modifications des caractéristiques des particules en suspension dans

l’air. Le prélèvement même de particules à partir d’une dispersion tridimensionnelle sur la surface d’un

filtre bidimensionnelle peut être considéré comme apportant des modifications aux caractéristiques

des particules; en outre, pour la plupart des échantillons, certaines caractéristiques sont également

modifiées par les modes opératoires de préparation. Toutefois, les modes opératoires spécifiés dans

le présent document sont destinés à réduire au minimum la perturbation de la matière particulaire

recueillie et l’effet des perturbations qui se produisent peut être évalué.

Le présent document décrit la méthode d’analyse applicable à un seul filtre à air. Cependant, l’une des

plus grandes erreurs qui peut se produire lors de la caractérisation de l’amiante dans les atmosphères

ambiantes est associée à la variabilité entre des échantillons de filtre. Pour cette raison, il est nécessaire

de prévoir un plan d’échantillonnage répété afin de déterminer l’exactitude et la fidélité du présent

document.
vi © ISO 2019 – Tous droits réservés
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NORME INTERNATIONALE ISO 10312:2019(F)
Air ambiant — Dosage des fibres d'amiante — Méthode
par microscopie électronique à transmission par
transfert direct
1 Domaine d’application

Le présent document spécifie une méthode de référence utilisant la microscopie électronique à

transmission pour déterminer la concentration en fibres et structures d’amiante en suspension dans l’air

dans diverses atmosphères ambiantes, notamment les atmosphères intérieures de bâtiments, et pour

évaluer en détail les structures d’amiante dans les atmosphères. Cette méthode permet de déterminer

le(s) type(s) de fibres d’amiante présentes et comprend également le mesurage des longueurs, des

largeurs et des rapports longueur/largeur des structures d’amiante. Elle ne peut pas faire la différence

entre des fibres individuelles d’amiante et des fragments allongés (fragments de clivage et particules

[13]
aciculaires) d’analogues non asbestiformes du même minéral amphibole .
2 Références normatives

Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur

contenu, des exigences 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 s’applique (y compris les

éventuels amendements).
ISO 4225, Qualité de l’air — Aspects généraux — Vocabulaire
3 Termes et définitions

Pour les besoins du présent document, les termes et définitions de l’ISO 4225 ainsi que les suivants,

s’appliquent.

L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en

normalisation, consultables aux adresses suivantes:

— ISO Online browsing platform: disponible à l’adresse https:// www .iso .org/ obp;

— IEC Electropedia: disponible à l’adresse http:// www .electropedia .org/ .
3.1
aciculaire

forme d’un cristal extrêmement mince avec une section petite par rapport à sa longueur, par exemple

en forme d’aiguille
3.2
amphibole

groupe de minéraux formés de silicate de fer ou magnésium, étroitement liés sous forme cristalline,

avec la composition chimique nominale:
© ISO 2019 – Tous droits réservés 1
---------------------- Page: 7 ----------------------
ISO 10312:2019(F)
A B C T O (OH,F,Cl)
0-1 2 5 8 22 2
A = K, Na;
B = Fe , Mn, Mg, Ca, Na;
3+ 2+
C = Al, Cr, Ti, Fe , Mg, Fe ;
T = Si, Al, Cr, Fe , Ti

Note 1 à l'article: Dans certaines variétés d’amphibole, ces éléments peuvent être partiellement substitués par Li,

Pb ou Zn. L’amphibole est caractérisée par une double chaîne réticulée formée de tétraèdres Si-O avec un rapport

silicium/oxygène de 4/11, par des cristaux prismatiques en forme de colonne ou de fibre et par un clivage

prismatique en deux directions parallèles à la surface des cristaux et se croisant à des angles d’environ 56°

et 124°.
3.3
amiante amphibole
amphibole (3.2) ayant un faciès asbestiforme (3.5)
3.4
sensibilité analytique

concentration calculée de structures d’amiante (3.7) en suspension par litre d’air, équivalant à

l’observation d’une structure d’amiante (3.6) dans l’analyse
Note 1 à l'article: Elle est exprimée en nombre de structures/litre.

Note 2 à l'article: La présente méthode ne spécifie pas de sensibilité analytique unique. La sensibilité analytique

est déterminée par les besoins du mesurage et par les conditions observées sur l’échantillon préparé.

3.5
asbestiforme

type spécifique de minéral fibreux dans lequel les fibres (3.22) et les fibrilles possèdent une haute

résistance à la traction et une grande souplesse
3.6
amiante

groupe de minéraux de silicates appartenant aux groupes des amphiboles (3.2) et des serpentines, qui

se sont cristallisés en faciès asbestiforme (3.5), ce qui permet, lorsqu’ils sont traités ou broyés, de les

séparer facilement en fibres (3.22) longues, fines, souples et solides

Note 1 à l'article: Les numéros d’enregistrement du Chemical Abstracts Service pour les variétés d’amiante les

plus courantes sont: chrysotile (12001-29-5), crocidolite (12001-28-4), amiante grünérite (amosite) (12172-73-

5), amiante anthophyllite (77536-67-5), amiante trémolite (77536-68-6) et amiante actinolite (77536-66-4).

[19]

D’autres variétés d’amphibole asbestiforme, notamment l’amiante richtérite et l’amiante winchite peuvent

également être présentes dans certains produits tels que la vermiculite et le talc.

3.7
structure d’amiante

fibre (3.22) individuelle ou tout groupement contigu ou formé par chevauchement de fibres ou de

faisceaux d’ amiante (3.6), avec ou sans particules associées
3.8
rapport longueur/largeur
rapport de la longueur d’une particule à sa largeur
2 © ISO 2019 – Tous droits réservés
---------------------- Page: 8 ----------------------
ISO 10312:2019(F)
3.9
blanc

comptage de structures effectué sur des échantillons pour microscopie électronique à transmission

préparés à partir d’un filtre non utilisé pour déterminer la concentration en bruit de fond

3.10
longueur de caméra

longueur de projection équivalente entre l’échantillon et le diagramme de diffraction électronique, en

l’absence d’action d’une lentille
3.11
chrysotile

minéral fibreux du groupe des serpentines, ayant une composition répondant à la formule chimique

brute: Mg Si O (OH)
3 2 5 4

Note 1 à l'article: La plupart des chrysotiles naturels s’écartent peu de cette composition nominale. Dans certaines

variétés, il peut se produire une substitution mineure de silicium par de l’Al . Une substitution mineure de

3+ 2+ 3+ 2+ 2+ 2+

magnésium par de l’Al , du Fe , du Fe , du Ni , du Mn et du Co peut aussi se présenter. Le chrysotile est le

type d’amiante le plus répandu.
3.12
clivage
fracture d’un minéral dans l’une de ses directions cristallographiques
3.13
fragment de clivage
fragment de cristal délimité par les plans de clivage (3.12)

Note 1 à l'article: En général, le broyage de l’amphibole non asbestiforme produit des fragments allongés

conformes à la définition d’une fibre.
3.14
agglomérat
structure dans laquell
...

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