ISO 13794-2019 PDF

Full title and description

ISO 13794:2019 — Ambient air — Determination of asbestos fibres — Indirect-transfer transmission electron microscopy method. This International Standard specifies a reference method using transmission electron microscopy (TEM) with an indirect-transfer specimen preparation to determine airborne asbestos fibres and structures, including procedures for sample ashing and dispersion so that fibres incorporated in aggregates or composite particles are measured.

Abstract

The standard defines a TEM-based reference procedure to measure airborne asbestos fibres and bundles in a wide range of ambient atmospheres (including indoor air). It covers specimen preparation (including ashing and dispersion), measurement of fibre lengths, widths and aspect ratios, identification of asbestos type(s), and the calculation of total mass concentration of airborne asbestos using measured dimensions and relevant asbestos densities. The method notes limitations in distinguishing amphibole asbestos fibres from elongated cleavage fragments or non-asbestiform analogues of the same mineral group.

General information

• Status: Published and current (confirmed at ISO five-year review).
• Publication date: October 2019 (Edition 2, 2019-10).
• Publisher: International Organization for Standardization (ISO), Geneva.
• ICS / categories: 13.040.20 — Ambient atmospheres / air quality and sampling.
• Edition / version: Edition 2 (2019).
• Number of pages: 80 (as published by ISO; national adopters may list minor pagination differences).

Scope

Provides a reference method for determination of asbestos fibres and structures in ambient air using an indirect-transfer TEM technique. The procedure is suitable for detailed evaluation of asbestos structures in indoor and outdoor atmospheres, and includes sample preparation steps designed to free asbestos from particle aggregates so that all asbestos content is measured. The method also supports calculation of mass concentration from dimensional measurements but notes analytical limits when distinguishing some non-asbestiform mineral fragments from true asbestos fibres.

Key topics and requirements

• Specimen collection and indirect-transfer preparation including ashing and dispersion to expose fibres from aggregates.
• Transmission electron microscopy (TEM) as the analytical technique for counting and sizing fibres and bundles.
• Measurement of fibre dimensions (length, width) and aspect ratio to permit numerical and mass concentration calculations.
• Identification of asbestos type(s) using TEM (with ancillary analysis as applicable).
• Reporting requirements for counts, size distributions, calculated mass concentration and method limitations (e.g., inability to unequivocally distinguish amphibole cleavage fragments from asbestos in some cases).

Typical use and users

Used by environmental and analytical laboratories, occupational and public-health agencies, researchers, and consultants performing ambient and indoor air monitoring for asbestos. Typical applications include regulatory compliance sampling, exposure assessment, environmental impact investigations and detailed forensic or research analyses of asbestos in air.

Related standards

Closely related ISO methods for asbestos monitoring include ISO 10312:2019 (direct-transfer TEM method) and ISO 14966:2019 (scanning electron microscopy method for numerical concentration of inorganic fibrous particles). ISO 13794:1999 (the 1999 edition) was withdrawn and superseded by the 2019 edition.

Keywords

Asbestos, ambient air, transmission electron microscopy, TEM, indirect transfer, sample ashing, fibre counting, fibre sizing, mass concentration, air monitoring, ISO 13794.

FAQ

Q: What is this standard?

A: An ISO International Standard (ISO 13794:2019) that specifies an indirect-transfer TEM reference method for determining asbestos fibres and structures in ambient and indoor air.

Q: What does it cover?

A: It covers sample preparation (including ashing and dispersion), TEM analysis, measurement of fibre dimensions (length, width, aspect ratio), asbestos type identification and calculation of total mass concentration from dimensional data, plus reporting and method limitations.

Q: Who typically uses it?

A: Environmental and analytical laboratories, public- and occupational-health agencies, consultants and researchers conducting asbestos air monitoring and exposure assessments.

Q: Is it current or superseded?

A: Current — ISO 13794:2019 is the active edition (Edition 2, published October 2019) and has been reviewed/confirmed under ISO's periodic review process; the 1999 edition was withdrawn and superseded by the 2019 edition.

Q: Is it part of a series?

A: Yes — it is part of the suite of ISO methods for asbestos and fibrous-particle analysis developed under ISO/TC 146/SC 3. Related documents include ISO 10312 (direct-transfer TEM) and ISO 14966 (SEM for numerical concentration), which together provide complementary approaches for asbestos/fibrous-particle monitoring.

Q: What are the key keywords?

A: Asbestos, TEM, indirect transfer, ambient air, fibre counting, fibre sizing, mass concentration, air quality, ISO 13794.