ISO/PRF 22262-2

International
Standard
ISO 22262-2
Second edition
Air quality — Bulk materials —
Part 2:
Quantitative determination of
asbestos by gravimetric and
microscopical methods
Qualité de l'air — Matériaux solides —
Partie 2: Dosage quantitatif de l'amiante en utilisant les
méthodes gravimétrique et microscopique
PROOF/ÉPREUVE
Reference number
ISO 22262-2:2025(en) © ISO 2025

ISO 22262-2:2025(en)
© ISO 2025
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE
ii
ISO 22262-2:2025(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 6
5 Determination of analytical requirements . 6
6 Range . 7
7 Limit of quantification . 7
8 Principle . 8
9 Safety precautions. 8
10 Apparatus . 8
11 Reagents . 10
12 Sample size and homogeneity . 10
12.1 Sample size .10
12.2 Representative sample .10
13 Methods for gravimetric matrix reduction .11
13.1 General .11
13.2 Data recording .11
13.3 Selection and pre-treatment of a representative sub-sample . 13
13.3.1 General . 13
13.3.2 Plasters without aggregate . 13
13.3.3 Plasters with aggregate . 13
13.3.4 Cements with and without aggregate . 13
13.3.5 Floor tiles . 13
13.3.6 Asphaltic materials without aggregate .14
13.3.7 Asphaltic materials with aggregate .14
13.3.8 Caulkings, mastics, putties, groutings and wall joint compounds .14
13.3.9 Cellulosic materials .14
13.3.10 Textured coatings .14
13.4 Removal of organic materials by ashing .14
13.4.1 General .14
13.4.2 Procedure . 15
13.5 Acid treatment and sedimentation procedures . 15
13.5.1 General . 15
13.5.2 Procedure for acid treatment of samples containing soluble constituents, with
or without insoluble aggregate . 15
13.5.3 Procedure for resilient floor tile .17
13.5.4 Examination of materials for amphibole fibres .17
14 Procedures for quantification of the mass fraction of asbestos in the final residue from
gravimetric matrix reduction . .18
14.1 General .18
14.2 Examination of the residue on the filter and selection of the appropriate procedure .19
14.2.1 General .19
14.2.2 Gravimetric measurements alone .19
14.2.3 Visual estimation by PLM, SEM or TEM observation .19
14.2.4 Point counting by PLM or SEM . 20
14.2.5 Determination of asbestos mass fraction from fibre measurements made by
SEM or TEM .24
PROOF/ÉPREUVE
iii
ISO 22262-2:2025(en)
15 Determination of asbestos in talc and other mineral powders .26
15.1 General . 26
15.2 Separation of chrysotile and amphibole by heavy liquid centrifugation .27
15.3 Determination of chrysotile and amphibole in talc and other mineral powders by TEM .27
15.3.1 General .27
15.3.2 Specimen preparation .27
15.3.3 Determination of chrysotile and amphibole mass fraction . 28
15.3.4 Determination of chrysotile and amphibole numerical fibre concentrations . 28
15.4 Determination of the mass fraction of chrysotile and amphibole in talc and other
mineral powders by SEM . 28
16 Determination of asbestiform amphibole in vermiculite .28
16.1 General . 28
16.2 Required size of sample for analysis . 29
16.3 Sample pre-treatment . 29
16.3.1 Exfoliated vermiculite, loose fill vermiculite attic insulation and horticultural
vermiculite . 29
16.3.2 Vermiculite block fill insulation . 30
16.3.3 Vermiculite ore concentrate. 30
16.3.4 Vermiculite-containing horticultural products . 30
16.3.5 Sprayed vermiculite-containing fireproofing . 30
16.4 Separation of amphibole and measurement of the amphibole mass fraction .31
16.4.1 General .31
16.4.2 Manual separation of amphibole fibre bundles and weighing .31
16.4.3 Separation of amphibole by centrifugation in a heavy liquid .31
16.4.4 Confirmation of the absence of asbestos in the vermiculite sub-sample .32
17 Determination of compliance with legislative control limits .32
17.1 General .
...

ISO/TC 146/SC 3 N455
ISO 22262-2:2025(en)
ISO/TC 146/SC 3/WG 1
Secretariat: ANSI
Date: 2025-10-28
Air quality — Bulk materials —
Part 2:
Quantitative determination of asbestos by gravimetric and
microscopical methods
Second edition
Date: 2025-07-12
Qualité de l'air — Matériaux solides —
Partie 2: Dosage quantitatif de l'amiante en utilisant les méthodes gravimétrique et microscopique
PROOF
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'sISO’s member body in the country of the requester.
ISO Copyright Office copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Email: E-mail: copyright@iso.org
Website: www.iso.org
Published in Switzerland.
iii
Contents Page
Foreword . vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviated terms . 7
5 Determination of analytical requirements . 7
6 Range . 8
7 Limit of quantification . 9
8 Principle . 9
9 Safety precautions . 9
10 Apparatus . 9
11 Reagents . 11
12 Sample size and homogeneity . 11
12.1 Sample size . 11
12.2 Representative sample . 12
13 Methods for gravimetric matrix reduction . 12
13.1 General . 12
13.2 Data recording . 12
13.3 Selection and pre-treatment of a representative sub-sample . 15
13.4 Removal of organic materials by ashing . 16
13.5 Acid treatment and sedimentation procedures . 17
14 Procedures for quantification of the mass fraction of asbestos in the final residue from
gravimetric matrix reduction . 21
14.1 General . 21
14.2 Examination of the residue on the filter and selection of the appropriate procedure. 21
15 Determination of asbestos in talc and other mineral powders . 30
15.1 General . 30
15.2 Separation of chrysotile and amphibole by heavy liquid centrifugation . 30
15.3 Determination of chrysotile and amphibole in talc and other mineral powders by TEM . 31
15.4 Determination of the mass fraction of chrysotile and amphibole in talc and other mineral
powders by SEM . 32
16 Determination of asbestiform amphibole in vermiculite . 32
16.1 General . 32
16.2 Required size of sample for analysis . 33
16.3 Sample pre-treatment . 33
16.4 Separation of amphibole and measurement of the amphibole mass fraction . 35
17 Determination of compliance with legislative control limits . 36
17.1 General . 36
17.2 Gravimetry alone . 37
17.3 Gravimetry combined with visual estimation . 37
17.4 Gravimetry combined with point counting . 37
17.5 Quantitative SEM or TEM fibre counting . 41
iv
18 Method validation . 41
19 Test report . 41
Annex A (normative) Types of commercial asbestos-containing materials and optimum
analytical procedures . 43
Annex B (normative) Required centrifuge times for separation of amphibole in heavy liquid . 51
Annex C (normative) Examples of test report . 54
Bibliography . 60

v
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
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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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 22262-2:2014), which has been technically
revised.
The main changes are as follows:
— — Addition of procedures for determination of asbestos mass fraction and numerical fibre concentration
in talc and other mineral powders have been added;
— — Addition of an alternate procedure, following gravimetric matrix reduction, for determination of the
asbestos mass fraction on filters that exhibit only trace levels of fibres has been added.
A list of all parts in the ISO 22262 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
vi
Introduction
In the past, asbestos was used in a wide range of products. Materials containing high proportions of asbestos
were used in buildings and in industry for fireproofing, thermal insulation and acoustic insulation. Asbestos
was also used to reinforce materials, to improve fracture and bending characteristics. A large proportion of
the asbestos produced was used in asbestos-cement products. These include flat sheets, tiles and corrugated
sheets for roofing, pipes and open troughs for collection ofcollecting rainwater, and pressure pipes for supply
ofsupplying potable water. Asbestos was also incorporated into products such as decorative coatings and
plasters, glues, sealants and resins, floor tiles, gaskets and road paving. In some products asbestos was
incorporated to modify rheological properties, for example in the manufacture of ceiling tile panels and oil
drilling muds.
Three varieties of asbestos found extensive commercial application. Chrysotile accounted for approximately
95 % of consumption, and therefore this is the variety that is encountered most frequently during analysis of
samples. Amosite and crocidolite accounted for almost all of the balance, with a very small contribution from
anthophyllite. Amosite was generally used as fireproofing or in thermal insulation products. Crocidolite was
also used as fireproofing and thermal insulation products, but because it is highly resistant to acids, it also
found application as a reinforcing fibre in acid containers such as those used for lead-acid batteries, and in
some gaskets. Materials containing commercial anthophyllite are relatively rare, but it also has been used as
a filler and reinforcing fibre in composite materials, and as a filtration medium. Tremolite asbestos and
actinolite asbestos were not extensively used commercially, but they sometimes occur as contamination of
other commercial minerals. Richterite asbestos and winchiteWinchite asbestos occur at mass fractions
between 0,01 % and 6 % in vermiculite formerly mined at Libby, Montana, USA. Vermiculite from this source
was widely distributed and is often found as loose fill insulation and as a constituent in a range of construction
materials and fireproofing.
While the asbestos mass fraction in some products can be very high and in some cases approach 100 %, in
other products the mass fractions of asbestos used were significantly lower and often between 1 % and 15 %.
In some ceiling tile panels, the mass fraction of asbestos used was close to 1 %. There are only a few known
materials in which the asbestos mass fraction used was less than 1 %. Some adhesives, sealing compounds
and fillers were manufactured in which asbestos mass fractions were lower than 1 %. There are no known
commercially manufactured materials in which any one of the common asbestos varieties (chrysotile, amosite,
crocidolite or anthophyllite) was intentionally added at mass fractions lower than 0,1 %.
ISO 22262--1 specifies procedures for collection of samples and qualitative analysis of commercial bulk
materials for the p
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