In the analysis according to IFA method 7487, a previously determined quantity of a powdery substance is examined with regard to fibrous particles with asbestos spectra with the help of a scanning electron microscope (SEM) and energy dispersive X-ray microanalysis (EDX). This method focuses on the determination of asbestos content in mineral raw materials.
There is a limit of 0,1 % mass content of asbestos in hazardous substances containing asbestos, which may not be manufactured and used, as specified in the Ordinance on Hazardous Substances (GefStoffV) Annex IV II No. 1.
Mineral raw materials are considered free of asbestos if the determination of the mass content of free asbestos fibres is below 0,008 % mass content, according to detection limit of the method under standard conditions and this is proven in at least three determinations of the mass content at intervals of at least 30 days (TRGS 517).
This method is suitable for samples with particle sizes below approx. 100 µm. This includes most powders as well as respirable dusts. If the sample does not meet this condition, it is crushed before further analysis. A portion of the sample is weighed and placed in suspension. A portion of the suspension is pipetted and filtered. The analysis is again carried out with the help of a scanning electron microscope (SEM) and energy dispersive X-ray microanalysis (EDX).
The detection limit of the method is 0,008 % and thus fulfils the requirements of TRGS 517.