Asbestos Insulating Board (AIB)

Asbestos insulating board (AIB) is a low-density board manufactured from asbestos fibres mixed with a calcium silicate or calcium carbite binder. It typically contains between 15 % and 40 % amosite (brown asbestos), although some formulations also include chrysotile (white asbestos). AIB was one of the most versatile and widely used asbestos products in the construction industry from the 1930s to the mid-1980s.

AIB was employed in a wide range of applications including ceiling tiles, partition walls, fire-stop panels, column casings, soffits, window panels below radiators, and fire-door cores. Its popularity stemmed from excellent fire resistance, thermal insulation properties, and ease of cutting and installation. The board could be sawn, drilled, and nailed like timber, which unfortunately also made it easy to generate large quantities of asbestos dust during installation and later during maintenance or removal.

The material is classified as friable because it has a relatively low density and releases fibres readily when cut, drilled, broken, or abraded. Even surface damage from impacts or water ingress can liberate respirable fibres. This makes AIB significantly more dangerous than higher-density asbestos cement products.

In the UK, AIB is one of the most frequently encountered ACMs during refurbishment and demolition surveys. Production ceased in the mid-1980s when amosite was banned. Under UK CAR 2012, removal of AIB requires a licensed contractor if the work is not exempt short-duration work. In the US, OSHA classifies cutting and removal of AIB as Class II asbestos work, requiring specific controls.

Identifying AIB can be challenging because it closely resembles modern non-asbestos insulating boards. Sampling and laboratory analysis by a UKAS-accredited (UK) or NVLAP-accredited (US) laboratory is the only definitive identification method.