Asbestos Fireproofing Properties
Asbestos is a group of naturally-occurring, non-combustible silicate minerals composed of glass-like fibers.
There are two asbestos fiber classifications.
- Serpentine Class: Contains chrysotile or soft (white) asbestos.
- Amphibole Class: Contains hard, spiky crystals along with a range of colors like brown, blue and green.
The five sub-types of amphibole are:
Geographically, asbestos occurs all over the world. Serpentine-class asbestos is the most common natural form, and it was used extensively in fireproofing applications.
Amphibole classes are not as plentiful but tend to have a higher heat resistance when mixed as additives with other non-flammable products like gypsum and cement. Amphibole asbestos is a harder form and not as friable or easily turned to powder like serpentines.
Did You Know?
Mesothelioma Cancer Network Brief
By the 1980s, government regulations began to ban asbestos fireproofing products. The Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA) worked to stop asbestos material manufacture and distribution. But the damage had already been done for many American workers exposed to asbestos fibers in their workplace.
Geologically, asbestos formed under high heat and pressure. Nature let asbestos keep these fireproofing properties whether used in a pure, raw state or blended with a host of other materials.
Asbestos formed close to the surface, making extraction inexpensive. Supplies of asbestos were nearly inexhaustible, so the insatiable demand for asbestos throughout the twentieth century was filled continuously.