Dust out of substances that have a elongated shape. Fibres that are alveolar and have a length of more than 5 µm, a diameter of less than 3 µm and a length-diameter-ratio of more than 3 : 1 play a special rule in this regard. Fibres of this geometry are also called WHO-fibres or respirable fibres. E. g. asbestos, glass fibre, stone wool, slag wool, high temperature wool.
Special demands apply for processing and disposal. In Germany they are regulated in the following directives:
- Technischen Regeln für Gefahrstoffe TRGS 521 "Abbruch-, Sanierungs- und Instandhaltungsarbeiten mit alter Mineralwolle"
- TRGS 519 "Asbest-Abbruch, Sanierungs- oder Instandhaltungsarbeiten" festgelegt sind.
[source: Wikipedia DE]