Artificial mineral fibres (AMF) are inorganic, synthetic fibres made from mineral raw materials such as glass, natural stone or slag. They include continuous fibres, mineral wool, ceramic fibres and special fibres. In contrast to natural mineral fibres, AMFs are amorphous silicates. The chemical composition of AMFs varies widely.  The SiO2 – Al2O3 system is the most significant. It is a large group of different classes of fibres with different physical, chemical and biological properties.

The analyses are carried out by means of EDX detectors on fibres according to the WHO definition.  According to this, the length is over 5µm, the diameter is less than 3µm, and the length/diameter ratio is greater than 3 : 1. Based on the elemental composition, a CI index is determined for the fibres.

According to TRGS 905, the classification is based on the carcinogenicity index CI according to the categories for carcinogenic substances in Annex I of the CLP Regulation:

  • Category 1B applies to vitreous WHO fibres with a CI ≤ 30.
  • Category 2 applies to WHO vitreous fibres with a CI > 30 and < 40.
  • No classification is made for a CI ≥ 40.
  • However, the classification of WHO vitreous fibres can also be based on a carcinogenicity test with intraperitoneal application or the determination of the in vivo bio-resistance. For this purpose, the manufacturer’s data sheets or relevant product labels must be observed. If the CI index is < 40, the fibre material may nonetheless be classified as non-carcinogenic.