What is Asbestos?
Asbestos is a naturally forming mineral, which has been commercially mined for its useful properties. It is estimated that over 5 million tonnes of asbestos was imported into the United Kingdom. It was seen as a miracle fibre, which could be bonded into various building materials and woven into textiles. Also because it was cheaper than many building materials, it was used in construction when its excellent properties were not required. Asbestos still remains one of the most effective forms of fire protection known to man, and in many cases, asbestos materials remain in excellent condition for many decades.
The useful properties of asbestos are:
• Resistant to Chemicals
• Heat Resistant
• Low Thermal Conductivity
• Flexible
• High Tensile Strength
There are three main types of asbestos which were used in commercially extensive quantities. The bulk of the materials used within the UK had been imported from Canada or South Africa. These types of Asbestos are:
Chrysotile
A serpentine mineral and is commonly known as “white” asbestos. It is cream, white or pale green in its raw state and it’s soft curly fibres, when processed, make it ideal for spinning and weaving.
Chrysotile asbestos was the most commonly used form within the UK and was used in materials such as Asbestos Cement Products and various insulation materials, papers, gaskets, textured coatings and floor tiles.
Amosite
This
is the most common member of the amphibole group and is commonly known as “brown” asbestos.
Amosite fibres are brown or black when raw and when processed appear to be grey or brown. Typical applications for brown asbestos were pipe lagging or mixed as an Asbestos Insulation board (AIB).
Crocidolite
Is another member of the amphibole group and commonly known as “blue” asbestos. In it’s raw state the fibres are very dark in appearance and when processed appear a distinctive blue. Commonly used as sprayed insulation, Crocidolite is seen as one of the most deadly forms of asbestos.
These were the three main types of asbestos used within the construction and refurbishment of buildings. One important point to note is that although the forms of asbestos are commonly referred to by colour, this does not prove an ideal way to identify the material.
There were also three other forms of mined asbestos namely Anthophylite, Tremolite & Actinolite. These forms are quite rare and are only occasionally found within the UK.
History
Asbestos has been used in fire resistance applications, such as crematoriums, for centuries but was first used in building and construction as far back as the late 1800’s. Extensive usage occurred within the construction of buildings, between the late 1940’s until the mid 1970’s. However, some asbestos products were still being installed in buildings as late as 1999.
Because of this, coupled with the increasing number of asbestos related illnesses and expected deaths, legislation is now based on a new duty to manage asbestos, The Control of Asbestos at Work Regulations 2006 (CAW 2006). This new regulation gives specific guidance on who the duty holder is and their responsibilities. Principally the duty holder must find out the location and quantity of all asbestos materials in their building and the condition of that asbestos must also be assessed.
Hence the requirement to undertake an asbestos building survey,and from the resulting survey report, a written management plan can be put in place and implemented. Such a plan is also a requirement of the new regulations. This management plan must be reviewed and updated on a regular basis. and this information must be made available to all employees, contractors and emergency services who are on site.
Common Asbestos Products
Although not entirely comprehensive the below list gives an indication of the common forms of asbestos and where it can be found. For a more complete list refer to MDHS 100 or the HSE document “Asbestos Essentials”: |
Asbestos in it's natural form
