ISO 22262-2:2014

Overview

ISO 22262-2:2014 - Air quality - Bulk materials - Part 2: Quantitative determination of asbestos by gravimetric and microscopical methods - specifies validated procedures to quantify asbestos mass fractions generally below approximately 5% in bulk commercial materials. The standard extends qualitative screening in ISO 22262-1 by defining gravimetric matrix reduction and microscopical workflows for materials where untreated microscopy is unreliable or insufficiently precise to determine regulatory status.

Key technical topics and requirements

• Scope and applicability: Designed for materials where a more precise asbestos mass-fraction measurement is needed (e.g., resilient floor tiles, asphaltic materials, roofing felts, wall and ceiling plasters, and mineral products such as talc, vermiculite, wollastonite, dolomite, calcite).
• Analytical principle: Combines gravimetric reduction (removal of matrix by ashing, acid treatment, sedimentation, heavy-liquid separation) with microscopical quantification (optical microscopy and electron microscopy methods referenced).
• Sample handling: Defines requirements for sample size, homogeneity, and representative sub-sampling to ensure reliable quantitative results.
• Matrix reduction techniques: Procedures include controlled ashing, acid digestion, sedimentation and density separation to concentrate asbestos fibres before analysis.
• Asbestos identification and quantification: Guidance on examination of final residues on filters, selection of appropriate counting/estimation procedures (visual estimation, point counting, SEM/TEM fibre counting) and determination of limit of quantification.
• Special cases: Dedicated procedures for vermiculite (asbestiform amphiboles) and talc, including sample pre-treatment and amphibole separation.
• Compliance and reporting: Methods to determine compliance with legislative control limits and requirements for test reports; normative annexes give recommended procedures and examples of test reports.

Practical applications and users

ISO 22262-2 is used by:

• Accredited analytical laboratories performing regulatory compliance testing
• Environmental and industrial hygienists assessing materials for renovation or demolition
• Building surveyors and asbestos consultants needing quantitative confirmation of low-level asbestos content
• Manufacturers and mineral producers (talc, vermiculite) for product characterization and quality control
• Regulators and enforcement bodies requiring reliable mass-fraction data to classify materials against control limits

This part is intended for knowledgeable analysts already familiar with ISO 22262-1; it does not teach fundamental microscopical techniques.

Related standards

• ISO 22262-1:2012 - Sampling and qualitative determination of asbestos in commercial bulk materials (prerequisite)
• ISO 13794:1999 - Indirect-transfer TEM method for asbestos fibres
• ISO 22262-3 (XRD method) - under development (referenced in the series)

Keywords: ISO 22262-2, asbestos quantification, gravimetric matrix reduction, microscopic methods, vermiculite, talc, asbestos mass fraction, bulk materials, air quality, asbestos testing.