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Disinfecting asbestos cement products following
disease |
Disinfecting asbestos cement products following disease
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. It is unlikely that low-density
asbestos containing materials will have been used in animal housing.
The release of asbestos fibres is dangerous to health.
Asbestos cement products in good condition, which are not being abraded,
will not be releasing dangerous quantities of fibres. If asbestos cement
products need to be worked on, in any way that will release fibres the
correct precautions must be used. See the AIC advice note ‘Working
with asbestos cement products’ Please add a link
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 de-greased and disinfected.
Any internal surfaces such, as the undersides of the roof that have not
been in contact with the animals just need to be disinfected. Because
asbestos cement products are alkaline in nature it is preferable if the
de-greasing and disinfectant 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 wetted and carefully bagged for disposal as above.
- 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 though
be possible to close the slurry system, direct the run off 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 this is carefully carried out
it should not damage asbestos cement sheets, but 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, which could cause
unusual stresses.
- Low pressure mist spray: This is the preferable
method of cleaning asbestos containing materials that have not been
in contact with the animals or their wastes, it should not create large
amounts of slurry and yet if the surfaces are properly wetted with the
correct alkali product it should adequately disinfect the area.
- Detergent use: Where the asbestos cement is soiled
and needs to be cleaned it is preferable to spray detergent on the surface
and leave to soak, then remove the soiling with care, using a low pressure
hose at approximately 45deg angle, 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 is
being damaged then too much force is being used and the run off must
be collected whilst still wet and buried.
- If at any time operatives need to work at height
to carry out their duties 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 of each
site prior to the start of work and method statements written to ensure
that the risks are reduced to the minimum.
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