What is asbestos?
Asbestos is a naturally occurring fibrous crystalline mineral, found in rock formations. Three main types of asbestos have been mined in Australia, including crocidolite (blue asbestos), amosite (brown asbestos) and chrysotile (white asbestos).
After mining, the mineral was further processed by breaking down clumps of fibres into groups of loose fibres. It was mixed with other materials to produce a variety of products.
Asbestos cement was produced by mixing asbestos fibres with Portland cement and water. The asbestos fibre was added as reinforcement, to increase the strength of the product. Asbestos cement products typically contain 10-15 percent asbestos fibre by weight.
How do you recognise asbestos products?
Generally, a person cannot determine whether a material contains asbestos simply by looking at it. Careful visual examination and the use of a microscope is the only way to verify the presence of asbestos. If in doubt, treat suspect material as though it does contain asbestos just to be on the safe side. In its raw form asbestos is well known to cause health effects in humans.
What are the health effects caused by exposure to asbestos cement products?
Generally, undisturbed asbestos cement products do not pose a health risk, as the fibres are bound together in a solid cement matrix. However, if the material is damaged or disturbed, fibres may be released into the air. The use of power tools for cutting, drilling, grinding, sanding or sawing the material can release a significant number of fibres. The use of high-pressure water blasters to clean the material prior to painting can also release large numbers of fibres so it is important to never perform these activities.
In most cases, the presence of asbestos cement building materials in a home (i.e a dividing fence) is no cause for alarm. If the materials are in good condition and are not disturbed, they do not present a health hazard. Disturbing the material (e.g by removal) may create a health hazard where none previously existed.
Renovating buildings containing asbestos cement products.
Special precautions must be taken when renovating buildings containing asbestos cement products, to prevent fibres entering the atmosphere. As far as practicable, asbestos cement material must not be broken, abraded or otherwise disturbed.
If it is necessary to cut holes in asbestos cement material, only non-powered hand tools may be used, or power tools that incorporate dust suppression or dust extraction equipment attachments that are specifically designed to collect asbestos fibres.
The material should be kept wet, or other practical measures taken to keep the creation of airborne fibres to a minimum.
Suitable personal protective equipment should be worn including:
- P1, P2 or P3 respirator (depending on the work undertaken)
- Disposable coveralls
- Safety goggles
- Disposable gloves
If significant cutting or abrasion of the material is required, the asbestos cement material should be removed, and replaced with non-asbestos materials. If in doubt, seek advice from a building consultant.
All work performed by contractors must comply with the requirements of Worksafe (Department of Consumer and Employment Protection) and the Health (Asbestos) Regulations 1992. Details of these requirements can be obtained from the WorkSafe Division of the Department of Consumer & Employment Protection.
How to safely remove and dispose of asbestos cement products
Special precautions must be taken when removing asbestos cement products, this is why you should seek the services of an asbestos removal contractor and as a last resort choose to remove the material yourself. If you choose to remove the material yourself, you are required to comply with the Health (Asbestos) Regulations 1992 by taking the following precautions:
- Remove all movable furniture and fittings from the room.
- Turn off heating/air conditioning systems.
- Isolate the area and prevent access to members of the family, visitors etc.
- Wear suitable personal protective equipment.
- Disposable coveralls.
- Safety goggles.
- Disposable gloves.
- Prior to removal gently spray the asbestos cement with water or a PVA (poly vinyl acetate) solution, to minimise the creation of airborne dust. Beware that an Asbestos Cement roof can be slippery when wet.
- Remove the asbestos cement products with minimal breakage. Do not use excess force so only use non-powered hand tools.
- Stack the asbestos cement sheets on 0.2mm thick polythene (plastic) sheeting. To prevent releasing fibres, avoid sliding the sheets together. Wrap the plastic around the material and seal it into bundles.
- Small pieces of asbestos cement can be collected in heavy-duty polyethylene bags, approximately 0.2mm thick. Bags should be filled to no more than 50 per cent capacity.
- Label or mark the bundles with the words “CAUTION ASBESTOS” in lettering at least 40mm high.
- Clean up any residue material using a vacuum cleaner fitted with a HEPA filter. Do not use an ordinary household vacuum cleaner.
- Dispose of asbestos material at an approved landfill site, a list can be obtained from the Department of Environmental Protection or the Department of Health. You must inform the operator of the site that the waste is or contains asbestos on arrival.
Removing asbestos cement fences
When removing asbestos cement fence sheeting, it is important to ensure that all of the material is removed, including the below ground section. Dig a trench around the fence, making sure you do not dig into the fence and break up the material. Remove the entire sheet, wrap it in labelled polythene sheeting, and dispose of promptly.
For further information download Removing Absestos brochure.
How to maintain an asbestos cement roof
Asbestos cement roofs should be regularly maintained using the following procedures:
- Inspect asbestos cement roofs regularly for signs of deterioration and damage.
- Clean gutters and drains annually by thoroughly wetting the waste material and collecting it in heavy-duty plastic bags for disposal at a landfill accepting asbestos waste.
- Prune all trees and branches 600mm away from asbestos cement roofing.
- Do not clean the roof unless absolutely necessary. If cleaning is necessary (e.g to remove dead moss and algae) a surface biocide can be applied, then removed using water and gentle brushing (with a soft bristled brush). During this procedure, the material must be kept wet at all times. CAUTION: An asbestos cement roof can be very slippery when wet
Using all reasonable measures when dealing with Asbestos
You must take all reasonable measures to ensure asbestos fibres are not released into the air. Reasonable measures include the following;
- Using water or other practical measures to keep airborne material containing asbestos to a minimum.
- Not using any tools other than non-powered hand tools or portable power tools that incorporate dust suppression or dust extraction attachments designed to collect asbestos fibers.
- Using only vacuum cleaning equipment designed to collect asbestos fibers.
- Not using a high pressure water jet, or compressed air, unless in a manner which adequately prevents asbestos fibers entering the atmosphere and which is approved in writing by the Executive Director, Public Health.
- Ensuring, so far as is reasonably practicable, that material containing asbestos is not broken or abraded.