Where is Asbestos Found in Buildings

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Some Asbestos containing materials (ACM's) are vunerable to damage and are more likely to give off fibres than others.In general, ACM's that contain a high percentage of Asbestos are more easily damaged. The list below is roughly in order of ease of fibre release.Sprayed Asbestos and Asbestos loose Packing.Moulded or Preformed lagging.Sprayed Asbestos - Generally used as fire protection in ducts.

Insulating boards and thermal insulation.

Some ceiling tiles.

Millboard, paper and paper products.

Asbestos cement products.

Bitumen roofing materials.

Vinyl or thermoplastic floor tiles.

Asbestos Insulation un-noticed behind a protective cover.

Asbestos Lagging again un-noticed within Aluminium covers

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The name Asbestos comes from the Greek word for incombustible. It is not a mineralogical definition, but the generic name given to a group of naturally occurring asbestiform silicate minerals with a fibrous geometry length 3 x width. Once mined, the rocks are crushed and fibrous strands which are strong (10 times that of nylon), flexible, resistant to acid and heat and very durable, are extracted. There are 6 different types of Asbestos falling into two different groups.

• Serpentine - Having a Sheet or layered Structure.
• Amphibole - Having a Chain like Structure.

All forms of Asbestos are indefinite polymers and immune to rot, corrosion and bacterial attack.

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There are 3 main types of Asbestos found in Premises Blue Asbestos (Crocidolite) - from the Amphibole group of minerals. It is a Sodium, Iron and Magnesium Silicate with blue straight fibres. It is hydrophobic with a decomposition temperature of 800°c. Brown Asbestos (Amosite) - from the Amphibole group of minerals, containing Iron and Magnesium with pale brown needle like fibres. It is hydrophobic with a decomposition temperature of 600° - 900°c. White Asbestos (Chrysotile) - from the Serpentine group of minerals. It is a Magnesium Silicate with curly flexible white fibres with splayed ends and kinks. It is hydrophillic with a decomposition temperature of 800° - 850°c. Although obvious when first mined, with the effects of age, heat and additives, they cannot be identified by colour alone. This has to be done by specialist laboratories belonging to the United Kingdom Accreditated Service (UKAS).

Why is Asbestos Dangerous ?

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Health affects are associated with respirable fiberous dust, i.e. unit density particles with a diameter less than 7 micrometers. Fibres and dust satisfying this criteria are capable of reaching the nonciliated portion of the lungs where gas exchange takes place.

Asbestos fibres are 2000 times thinner than human hair and are resistant to chemical decomposition and in particular biological action.

Asbestos fibre masses tend to break easily into dust composed of tiny particles. Breathing in air containing asbestos fibres may induce inflamation in the lungs that in turn generates oxidants that can lead to asbestos related diseases (ARD's) mainly cancers of the lung and the chest lining.

A Piece of Blue Asbestos (Crocidolite)

All types of asbestos are classed as category 1 carcinogenic. Fibre length, biopersistance and inflamation are the major determinants of fibre toxicity and carcinogenicity.

Asbestos is only a risk to health if asbestos fibres are released into the air and breathed in.

Within industry a safe maximum level of exposure has been agreed, however scientific evidence on what precise level of exposure causes disease is unclear.

Past exposure to asbestos currently kills 3500 - 5000 people a year in Great Britain. This number is expected to continue to rise for the next 10 years.

There is no cure for Asbestos related diseases. Only by minimising or preventing exposures to asbestos fibres now, will asbestos related diseases (ARD's) be wiped out.