What Is Asbestos?

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Asbestos (from the Greek for inextinguishable) is a general term covering two distinct groups of fibrous minerals. From Serpentine rock is derived Chrysotile or White Asbestos, a magnesium silicate. From Amphiboles rock are derived Amosite or Brown Asbestos and Crocidolite or Blue Asbestos, and of a lesser commercial significance, Anthophyllite, Tremolite and Actinolite.

There are in fact at least 30 types of asbestiform minerals but only the above mentioned are of any industrial significance. All asbestos types have a number of properties that have made them invaluable in many industrial applications.

Chrysotile has a very good resistance to alkalis.
Amosite has a very good resistance to high temperature.
Crocidolite has a very good resistance to acids.

The main sources of Chrysotile asbestos, the commonest fibre in industrial use, were mined in Quebec, British Columbia, South Africa, Russia, Italy, America, Greece, and Cyprus. Crocidolite was mined in South Africa and Australia and Amosite was mined in Australia and South Africa (The name Amosite is derived from AMOSA – Asbestos Mines Of South Africa).

The main sources of Chrysotile asbestos, the commonest fibre in industrial use, were mined in Quebec, British Columbia, South Africa, Russia, Italy, America, Greece, and Cyprus. Crocidolite was mined in South Africa and Australia and Amosite was mined in Australia and South Africa (The name Amosite is derived from AMOSA – Asbestos Mines Of South Africa).

What Materials Contain Asbestos?

Hand held dryers
Brake shoes and pads
Clutch facings
Electric blankets
Gaskets
Clothes dryers
Sheet gaskets
Boilers Automotive gaskets
Coal and wood burning stove door gaskets
Asbestos cement pipe and fittings
Paints, coatings, sealants:
Asbestos cement sheets
Asphaltic compounds
Asbestos cement shingles
Buffing and polishing compounds
Caulking and patching compounds
Body filler
Radiator sealant
Drilling fluids
Transmissions, mufflers Plaster and stucco
Textured paints and tile cement
Wallboard
Textile and felt products:
Hoods and vents Cloth (aprons, gloves, suits, blankets)
Roofing and roof shinglese
Fire hoses
Cable and electrical wire insulation
Ironing board pads
Switchboards
Piano and organ felts
Electronic motor components
Theater curtains
Felts and papers
Roofing and felts
Distress flares
Pipe-work wrap
Reinforced plastic toilet cisterns & seats
Blackboards
Vinyl-asbestos floor tile
Lamp sockets
Asbestos-felt backed vinyl sheet flooring
Linings for vaults, safes, filing cabinets

List of Typical asbestos containing materials found in buildings:

Pipe insulation Roofing felts
Tank and roof insulation
Floor tiles
Thermal insulation
Suspended ceiling tiles
Firebreak boards
Textured coatings such as Artex
Wall lining panels
Decorative panels, soffit and fascia boards
Insulation board
Sprayed acoustic coatings and fire insulation
Flues
Gaskets and washers to plant and machinery
Partitioning
Fire resistant blankets, gloves, mattresses, curtains etc
Roof slates
Insulation paper/cardboard under pipe lagging and floor tiles
Strings for sealing radiators
Jointing and packing yarns and materials to boilers, ovens, electric cables and fuse boards, flues, brickwork
String around glazing
Preformed products such as cable conduits, rainwater goods, fencing, roof promenade tiles, window sills, bath panels, draining boards, worktops, ducts
Resin wc cisterns
Roof sheets and cladding

How Long Has Asbestos Been Used For

The main sources of Chrysotile asbestos, the commonest fibre in industrial use, were mined in Quebec, British Columbia, South Africa, Russia, Italy, America, Greece, and Cyprus. Crocidolite was mined in South Africa and Australia and Amosite was mined in Australia and South Africa (The name Amosite is derived from AMOSA – Asbestos Mines Of South Africa).

When Does Asbestos Become A Hazard?

Asbestos is not always an immediate hazard. In fact, if asbestos can be maintained in good condition, it is recommended that it be left alone and periodic surveillance performed to monitor its condition. It is only when asbestos containing materials (ACM) are disturbed or the materials become damaged that the risk to exposure is increased. When the materials are damaged, the fibres can separate and may become airborne.

Why Asbestos A Hazard?

It was discovered in the 1930s that when the microscopic asbestos fibres (up to 100 times finer than human hair) become airborne they can be inhaled. The fibres are so inert that they cannot be dispelled from the lungs, and can cause cancer. Asbestos is made up of microscopic bundles of fibres that may become airborne when disturbed. Inhaled asbestos fibres can cause significant reperatory health problems.
Researchers still have not determined a “safe level” of exposure, but we know the greater and longer the exposure, the greater the risk of contracting an asbestos related disease. Asbestos related diseases kill more people than any other single work-related cause – about 2500 – 3000 people a year in the UK. There is a long latent period between exposure and onset of disease (15 – 60 years) so that most of the deaths seen today are from exposures during the 1950s – 1960s when asbestos was widely used.

Asbestos Facts

The tensile strength of some individual asbestos fibres has been recorded as high as 10 times that of nylon

Asbestos fibres are said to be a constituent of at least 3000 products

Clay pots reinforced with asbestos fibres have been discovered in Finland dating back to 2500BC, and other stone age cooking pots have been found to incorporate asbestos.

To extract asbestos fibres, the excavated rock is crushed and screened with up to 30 tonnes of rock yielding a tonne of fibre.

The ancient Egyptian, Greek and Romans would wrap their dead in asbestos woven cloth to preserve the ashes in funeral fires.

Tests at the Building Research Establishment found that a floor sprayed with one-inch of asbestos withstood a mean temperature of 1000°C for four hours without damage.

Chrysotile (White asbestos) only starts to dehydrate at temperatures above 500°C and fuses at about 1500°C

During mining, Asbestos is found in layers, sometimes only a few centimetres thick, between rocks of the same chemical composition. The fibres can be separated by hand.

Until recently, Asbestos pipes were used in beer and medicine filters because they absorb bacteria and clarify the liquids. No asbestos related disease has ever been recorded as a result. Many asbestos cement pipes are still in use and will continue to be used for many years to come.

Guides and further reading on Asbestos

How to deal with asbestos
What is asbestos
Asbestos waste collection
Asbestos diseases