Independant asbestos Information

Asbestos Cement Products

Asbestos is a naturally occurring substance, so some asbestos fibres are naturally liberated into the atmosphere. Everybody is exposed to some asbestos fibres at all times, whether working under an asbestos cement roof, playing in the local park or sailing across the ocean. At the very low natural levels they do not cause a danger, they become dangerous when the level of free fibres is increased by the inappropriate use by man

The Asbestos (Prohibitions) (Amendment) Regulations S.I. 1999 No. 2373/99 imposed a total ban from November 24th, 1999 on the selling and fixing of asbestos containing products. This ban extends to selling and fixing second-hand asbestos cement products. It does not affect the sale of property that contains any asbestos cement product.

It does not mean that asbestos-containing materials should be removed just because they contain asbestos, this would be counter productive. The DETR give the guiding principles for the management of asbestos materials as:

  • Asbestos materials, which are sound, undamaged and not releasing fibres should not be disturbed. Their condition should be monitored on a regular basis.
  • Where possible damaged materials should be repaired and then protected as necessary, provided that the repair or sealing will be durable and not likely to be disturbed.
  • Removal should only be performed where repair is not possible or the material is likely to be disturbed.

The Health and Safety Executive (HSE) published in 1999 guidance in the form of ‘Working with Asbestos Cement – HSG 189/2 @ £7.50. Other important reading is the Approved Code of Practice ‘Work with materials containing asbestos, Control of Asbestos Regulations 2006’ L 143 @ £13.50, A comprehensive guide to managing asbestos in premises HSG 227 @ £12.50 and should be required reading for anyone working on products, which may contain asbestos.

The handling of low-density insulation boards and spray coatings containing asbestos is a skilled job that must be carried out by a contractor licensed by the HSE to handle these products and is not covered by this guidance note. The following advice is given for those working with asbestos cement products.

Asbestos Cement

Asbestos Cement is primarily a cement-based product where about 10% to 15% w/w asbestos fibres are added to reinforce the cement. Asbestos cement is weatherproof in that although it will absorb moisture, the water does not pass through the product. It was used for corrugated sheets, slates, moulded fittings, soffits and undercloak, water cisterns, rainwater gutters, down pipes, pressure pipes, underground drainage and sewer pipes, sills, copings, chalkboards, fascias, infill panels, etc. It is sometimes difficult to tell the difference between an asbestos cement product and a low-density insulation board. Where the product has been used as a roofing or cladding product, open to the weather, you can be confident that the product is asbestos cement. Manufacture of all low density products was stopped in the late 70’s and since they were not weather resistant, if they had been fixed outside they would have broken down long before now. If the product is moulded it will be asbestos cement as low-density products were not moulded, except as half rounds for pipe lagging.

When cementitious products like asbestos cement were manufactured, they had a cement-rich surface. The asbestos fibres were encapsulated within. Thus, occupants of buildings with asbestos cement sheet or slate roofs are unlikely to be at any greater risk than people outside in the fresh air. The small quantities of fibres released during natural weathering are unlikely to be dangerous but significant and possibly dangerous amounts of fibre can be released if the products are subject to any abrasive cleaning or working. Thus, roofing operatives are more at risk from fibre exposure than any residents inside a building. It is important therefore that building owners keep a note of any asbestos containing products in his building and advises any contractors of their position, so that they can take the necessary precautions.


General Guidance on the Working with Asbestos Cement Products

The precautions required when working with an asbestos cement product are relatively easy but must be followed or there is the risk of creating dangerous quantities of fibres. If the precautions listed below are followed it is unlikely that the Control level or action level will be breached. There is not a requirement to use a “licensed contractor” but the contractor should be competent.

  • Carry out a risk assessment and write a method statement to ensure that the risk is reduced to the minimum possible and certainly that any fibre release is below the 10 Minute Limit and Control limit and set out in the Control of Asbestos Regulations 2006. Information on the 10 Minute Level and Control Limits can be found in the 'Approved Code of Practice The Management of Asbestos in Non-Domestic Premises', L127, ISBN 0 7176 6209.
  • Ensure the operatives know that they are working on asbestos containing products and that that they are adequately trained.
  • Segregate the working areas with warning signs
  • The operatives should preferably wear a disposable mask that is CE marked to EN 149 with FFP3 particulate filters and disposable overalls, which should be disposed of at the end of the shift as asbestos waste.
  • When working at heights follow the advice in HSG 33 Health and safety in roof work (1998). Old asbestos cement sheets are very fragile.
  • Keep the material wet when working on it.
  • Avoid using power tools and breaking asbestos containing products but carefully remove or crop fixings so that the product can be removed in one piece. Carefully carry to the ground and either double wrap in polythene or place in a covered skip.
  • Where it is necessary to cut or drill asbestos cement sheets, ensure the material is wet and if possible scribe and break, if this is not possible use hand tools, preferably in the open air.
  • Keep the site clean and tidy at all times and clean up after work by dampening any dust and carefully placing in a polythene bag for disposal as asbestos waste.

Where an asbestos cement roof or cladding is being repaired it is lawful to reuse the existing asbestos cement sheets as long as the correct working practices are used to keep asbestos exposure of the operatives to the minimum possible. The AIC does not accept that this is good practice, removing and replacing a sheet will put extra stress on to it and shorten even further the second hand sheets life. We recommend that whenever an asbestos cement product is removed it be replaced with a non-asbestos alternative.

Where an asbestos cement corrugated roof has come to the end of its economic life, rather than replacing it, it may be safer and more cost effective to leave the sheets in place and over-roof with a non asbestos roofing sheet, adding insulation if required. This should be discussed with you Competent Contractor or Designer.

Cleaning Asbestos Cement Roofs.

This should only be carried out if it can not be avoided, moss and lichens although some may think them unsightly are not normally detrimental. Asbestos cement is very fragile and so the recommendations in HSG 33 Health and safety in roof work (1998) must be followed.

Do not clean by dry scraping or by pressure washing, both can produce dangerous quantities of free asbestos fibres. Either:

  • Use remote cleaning. This technique involves skilled operatives using units with enclosed rotary cleaning heads and high-pressure water jets, the filtering of the water run off and the disposal of the filter waste as asbestos waste. It should only be carried out by skilled specialist contractors.
  • Cleaning with surface biocides. The biocides are applied with low-pressure sprays or as washes. The roof is then left for the moss and lichen to die, when it can be gently brushed from the roof with soft brushes. It is important that the roof is kept wet during the brushing and the waste is carefully collected placed in plastic bags and disposed of as asbestos waste.

Waste Disposal

Asbestos waste is any waste, which contains more than 0.1% w/w asbestos. It is subject to the waste management controls set out in the Hazardous Waste (England and Wales) Regulations 2005 and the agricultural waste regulations, with most properties if more than 200kg of asbestos containing waste (500kg for agricultural asbestos waste) is removed from site then the site has to be registered as a hazardous waste producer with the Environment Agency. The waste must be consigned as soon as possible by a licensed haulier to a dump licensed to take asbestos. Your local authority should have a list of licensed haulier's and waste dumps in you area.

The above is only a brief guide, it is not a complete guide to Health and Safety responsibilities when dealing with asbestos containing products, for more information contact your competent contractor, or designer.

The above guidance is given with the best intentions but nothing in this advice shall create or be deemed to create any obligations, whether expressed or implied, on the AIC.


         

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We have done our best to ensure that any information provided is accurate but it has been obtained from a number of different sources and so the Asbestos Information Centre can not be held responsible for any inaccuracies. If you do notice any inaccuracies please advise us at info@aic.org.uk so that they can be corrected. This web site is not a complete guide to the Health and Safety responsibilities when dealing with asbestos containing products. The information given is of a general nature and so does not address the specific circumstances of any particular situation. The guidance is given with the best intentions but nothing in this web site shall create or be deemed to create any obligations, whether expressed or implied, on the AIC.