Asbestos Knowledge Base
Asbestos is the collective name for a group of fibrous minerals which are mechanically strong and resistant to heat and chemicals. Some forms are resistant to acids and alkalis. Because of its fibrous nature it can be spun and woven into yarns and fabrics and used to reinforce cement and plastics. There are three main types of asbestos, commonly called white, brown and blue, these are:
- Chrysotile (white)
- Crocidolite (blue)
- Amosite (brown)
All are dangerous, but blue and brown asbestos are known to be more hazardous than white. They cannot be identifiedby their colour alone.
Chrysotile (white) was the only form of asbestos that could be used in the UK until recent times, however new legislation in force from November 1999 has banned the use of Chrysotile as well as the other forms. Chrysotile (white) asbestos was usedin the UK mostly for the manufacture of asbestos cement products, asbestos textiles, and friction materials such as brake pads.
Amosite Asbestos (brown) and Crocidolite Asbestos (blue) - the two most dangerous forms of asbestos - have not been imported into or used in the UK for many years but they may be found within some existing structures. Anthophyllite, tremolite and actinolite are three lesser used forms. Tremoliteis mainly found as a contaminant of chrysolite asbestos.
Asbestos minerals are crystalline and split longitudinally to form very fine fibres. Crocidolite and Amosite are amphiboles with straight and relatively brittle fibres. Chrysotile is a serpentine mineral with curled flexible fibres.