The following advice relates to asbestos cement products and does not apply to low-density asbestos containing products, i.e. those with a density of less than 1 Kg/cm3*.
The release of asbestos fibres is dangerous to health. Asbestos cement products in good condition, which are not being corroded in any way, will not be releasing dangerous quantities of fibres. If asbestos cement need to be worked on in any way that will release fibres, the correct precautions must be used.
Disinfecting Asbestos on a Farm
Following animal disease on a farm, it may be necessary for all the surfaces – both internally and externally – that have been in contact with animals or their wastes to be degreased and disinfected. Any internal surfaces, such as the undersides of the roof that have not been in contact with the animals, simply need to be disinfected. Because asbestos cement products are alkaline in nature, it is recommended that the degreasing and disinfecting products used are also alkaline. Acids may be neutralised so fast that their disinfectant properties may be compromised.
Different farms may use different processes to disinfect their buildings, and because many of the buildings will contain asbestos containing products, we have compiled the following advice to help ensure that the release of asbestos fibres is kept to a minimum.
- When working with asbestos cement materials, it is always advisable to ensure that the material is damp, which will help ensure that asbestos fibres are not released.
- Any waste that contains more than 0.1% asbestos must be treated as hazardous waste and under normal circumstances should be disposed of by employing a licensed haulier to take the waste to a licensed asbestos dump. When the waste has been generated on agricultural premises it can be treated as agricultural waste and disposed of in accordance with the Agricultural Waste Regulations.
- The slurry that is created from cleaning asbestos containing products with dusty surfaces will probably contain more than 0.1% asbestos and so it should be carefully shoveled, whilst still wet, into thick plastic bags which should then be sealed before disposal.
- Where dusty surfaces are being cleaned, they should not be vacuumed unless a special Type H vacuum cleaner is used. The dust should be dampened and carefully bagged for disposal as above.
Asbestos Cement Cleaning Methods
Pressure washing: different forms of asbestos containing materials will withstand different pressures before they are damaged. A fully-compressed flat sheet used in the construction of pig or calf pens will withstand higher pressures than a semi-compressed or corrugated sheet. We strongly suggest that a trial be carried out in an area that is hidden, to ascertain what pressure should be used. If the pressure is too high, there is the risk that a hole will be abraded through the sheet or the top laminations will be removed. This will release large quantities of asbestos. Even when the correct pressure is used on semi-compressed sheets, it is likely to scour the surface and create greater quantities of asbestos waste mixed with vast quantities of water, which may well find its way into the slurry system. To close off the slurry system and set up a system to filter the asbestos fibres out of the waste to the satisfaction of the HSE is likely to be very costly. It may however be possible to close the slurry system, direct the runoff water to a confined area outside, and let it soak away; this should leave the waste including the asbestos on the surface. Before it dries, the top 50mm of the soil and waste should be dug up, bagged and disposed of as above.
Steam-cleaning: if carefully carried out, this method should not damage asbestos cement sheets, however the steam should not be held in one place for too long as it could cause a marked increase in temperature. In a small confined area of the sheet, this could cause significant stresses that could lead to the release of dangerous amounts of asbestos fibres.
Low pressure mist spray: the preferable method for cleaning asbestos containing materials that have not been in contact with animals or their wastes. Using this method will not ordinarily create large amounts of slurry, and yet if the surfaces are properly wetted with the correct alkali product, it should adequately disinfect the desired area.
Detergent use: where the asbestos cement is soiled and needs to be cleaned, it is preferable to spray detergent on the surface and then leave to soak, before then removing the soil with care. To do so, you can use a low pressure hose at approximately a 45° angle, and where brushing is required to remove the dirt, only soft brushes should be used, ensuring that the surface is wet during the brushing. If the surface of the asbestos cement appears to be being damaged, then too much force is being applied and the runoff must be collected whilst still wet and buried.
- If at any time operatives need to work at a height to carry out their duties, then all the necessary precautions must be taken to ensure that they are protected from the risk of falling.
- The risks associated with asbestos fibre release and working at heights are not the only risks that may be faced by the operatives; a detailed risk assessment should be carried out at each site prior to the start of work, and method statements written to ensure that the risks are reduced to the minimum.
*For your reference, it is unlikely that low-density asbestos containing materials will have been used in animal housing.