The discovery of asbestos-containing materials (ACMs) hidden within the fabric of a building during renovations or demolition can often be missed simply because it is not recognised or identified by building contractors or premises owners / duty holders.
While asbestos awareness to the potential deadly health risks are more likely to be well-known today than during much of the twentieth century, those workers most likely to come into contact with asbestos today often fail to identify the material even at close quarters.
Asbestos survey and vital information
The problem tends to occur when an asbestos survey has not been carried out in advance of work proceeding or if a building survey had been completed previously, the vital information regarding the existence of asbestos had not been forwarded to all parties concerned.
The Health & Safety Executive (HSE) estimate that as many as half a million properties around the UK still retain hidden asbestos-containing materials. More than 1.8 million people are annually exposed to asbestos and at least 2,000 cases of mesothelioma and other asbestosis diseases diagnosed every year.
The most dangerous forms of asbestos – brown ( amosite) and blue ( crocidolite) – were banned from use by the 1985 UK Asbestos (Prohibition) Regulations but white (chrysotile) asbestos continued to be used in building items, such as AIB (asbestos insulating board), textured surface coatings, boiler pipe lagging, sprayed loft insulation, cement roofing and side panels
Hidden white asbestos materials
It wasn’t until 1999 that a ban on AIB was introduced and all white asbestos use was prohibited by an European Commission ruling in January 2005. It means that any building built or renovated up until the 1980s and 90s at least cannot be discounted from the possibility of containing hidden white asbestos materials.
Today, it’s very rare but still possible for asbestos to be found in some ceiling or vinyl floor tiles and the their adhesive backing. However, almost all the reports of workers breaking up asbestos materials found in buildings, from schools and colleges to housing estates and industrial units, tends to be in the form of AIB / millboard or cement-based products, such as roofing sheets.
Asbestos Insulating Board (AIB)
AIB was widely used in building construction as fire protection, thermal and acoustic insulation, resistance to moisture movement and general building board. It can be uncovered as firebreaks, partitions and ceilings, roof underlay, wall linings, external canopies, porch linings and service ducts.
In almost all cases, the asbestos panels have been painted or plastered over, at least more than once over the years, which can prevent easy, visual identification. Older blue and brown asbestos boards usually contain up to a 25 per cent asbestos fibres or combined with asbestos fibres in a calcium silicate.
Asbestos ‘Mill Board’
Millboard was used for general heat insulation and fire protection as well as insulation of electrical equipment and plant ( in industrial applications) and could contain between 40 per cent to more than 95 per cent asbestos in a mixture of clay and starch.
Asbestos Cement Profiled Sheets
When cement was mixed with between 10 – 15 per cent asbestos fibre, a rigid sheet less than five millimetres thick was produced and used in the manufacture of asbestos cement found in roofing, wall cladding and permanent shuttering until the end of 1999.
Asbestos Cement Compressed Flat Sheets
Found in partitioning and infill panels for housing, shuttering in industrial buildings, decorative panels for facings, bath panels, soffits, wall linings and ceilings, fire surrounds, weather boarding, cladding, decking and roof slates
All the above types of board and sheets are subject to surface abrasion and easily broken up to release substantial airborne, fibre dust particles.
Whenever any building known to have been constructed before the year 2000 is to be refurbished, a full asbestos survey should always be carried out in advance, which may also require material or in some cases, air samples to be scientifically analysed.
Removal of asbestos always requires specialist, licensed contractors, protective equipment and sealing of the affected area to avoid the risk of airborne contamination.