Asbestos Exposure in Materials

How could exposure to asbestos dust happen in the UK construction industry?

• Disturbing Older Buildings: Any building built before the year 2000 may contain asbestos materials. This can include within insulation, lagging, sprayed coatings and asbestos cement materials.
• Renovation, Repair, and Maintenance: Activities that disrupt the fabric of a building, such as drilling into walls, removing old floor tiles, replacing ceiling tiles, or repairing boilers are the primary causes of asbestos fibre release.
• Demolition Work: The total demolition of buildings containing asbestos materials creates the highest risk for large-scale fibre release if the asbestos has not been identified and removed before demolition.
• Handling Damaged Materials: Working with or near to damaged or degraded asbestos materials such as crumbling insulation or broken roof sheeting, can lead to breathing in dangerous asbestos fibres.
• Secondary Exposure: Those who are directly disturbing asbestos materials are at risk of breathing in asbestos fibres. However, it must not be forgotten that those working near to that person disturbing the asbestos materials could also be at risk of breathing in the dust created by the work and even family members are at risk of being exposed if asbestos contaminated work clothes are worn home or taken home to be washed.

Asbestos in construction materials

Asbestos materials were extensively used in the construction of domestic and industrial buildings between the 1950s and 1980s. Those workers who historically used the asbestos materials are at risk of developing asbestos related diseases, as well as people who are disturbing the materials today.

1. Asbestos Insulating Board (AIB)

A highly hazardous low-density material widely used in UK construction for fire protection and insulation purposes. It was used in ceiling tiles, wall panels and partitions, as well as soffits, service ducts and fire doors. AIB contains a high percentage of asbestos fibres, typically Amosite (brown asbestos) or Chrysotile (white asbestos). Because the board is soft and friable, it poses a high risk of releasing asbestos fibres when drilled, cut or damaged. Even the chipping off of a board corner releases asbestos fibres.

2. Asbestos cement/asbestos sheets

Asbestos cement is a “bonded material” usually containing Chrysotile (white asbestos) mixed with cement. When the material gets damaged, broken or weathered, it can release asbestos fibres into the air which can then be inhaled. Asbestos cement was often used in sheet form for roofing and cladding and also was used for guttering and water pipes.

3. Lagging – Asbestos lagging comes in many forms:

• Loose Asbestos Fibres: Typically during the 1960s and 1970s, loose asbestos fibres were mixed with water to create a lagging paste. The loose fibres were tipped from bags into buckets or oil drums which created huge clouds of dust. Water was then added, causing the asbestos fibres to fly up, and the mixture then stirred with a stick or the worker’s arm/hand to get it to the right consistency, adding more fibres or water as needed. Once the mixture had been made, it was applied to pipework and boilers. Over time, that lagging becomes dry and brittle, causing it to crack and fall off in sections if touched and realising fibres into the air.
• Moulded/Preformed Pipe Sections: These were rigid, pre-formed sections of asbestos lagging wrapped around pipework and often then painted particularly to identify hot water pipes.
• Fibrous Pipe Insulation/Asbestos Cloth Lagging: Soft, fibrous material (often white or grey) that flakes easily and was applied to pipes, valves, and boilers as a bandage wrap. The cloth often had very high levels of asbestos fibre content within it. Frequently found wrapped around pipes, boilers, calorifiers and in heating systems. It may look like a bandage, cloth, paper or felt covering.
• Asbestos Rope/String: Often came on a roll and the required length would be cut off with a knife and used to seal joints and fill in gaps. The rope came in different thicknesses and was often prodded into place to ensure a tight fit. When the rope/string is removed after years of it sitting in place, it is often brittle and damaged and comes out in pieces, which in turn allows dust to escape.
• Insulating Mattresses/Pads: Removable, asbestos fabric-covered pads used for insulating boilers, calorifiers, and flanges.
• Asbestos Spray (Limpet): Applied to structural steelwork, pipes and tanks for insulation and fire protection. It was applied wet and was a very messy job to do. The spray normally contained Crocidolite (blue asbestos).

4. Asbestos in wood products

Whilst wood does not contain asbestos fibres, asbestos sheeting was often used alongside wood for fire-proofing purposes. For example, fire-proof doors were often constructed of two sheets of wood with an asbestos sheet sandwiched in between them to provide the fire-proofing element.

5. Textured Coatings

These include“Artex”which contained asbestos fibres and is often found on ceilings and walls.

Reducing the Risk

To prevent exposure, it is crucial to:

• Identify asbestos containing materials before starting work.
• Where available, reference should be made to asbestos management plans and asbestos surveys to identify asbestos materials.
• Use trained professionals when dealing with asbestos materials.
• Follow Health and Safety Executive (HSE) guidance.
• If in doubt, it should be assumed that asbestos materials are present and the necessary precautions taken, unless you know the building was built from the year 2000 onwards.