Before it was banned in 1999, asbestos was long considered to be an ideal material for almost all types of thermal insulation. Asbestos is a naturally occurring mineral with a unique fibrous nature that gives it a cotton-like consistency. It is extremely resistant to heat, and the air between the mineral fibres slows the transfer of heat throughout the material. Due to its fibrous nature, it was also easy for manufacturers to mix asbestos into a range of other materials. Since it could be sourced relatively easily and cheaply before it’s cancer-causing health hazards were known, it would be difficult to name a type of commercial insulation product that did not contain it. Wherever insulation was needed, asbestos was typically the product of choice.
Thermal insulation that contains asbestos can be grouped into four major categories:
This insulation is designed to be blown into the hollow spaces inside walls and other structures or poured onto floors in the attic or loft. In many cases, this type of insulation would be made entirely of asbestos and is the most dangerous type of thermal insulation that contains the material. Since even a slight current of air can cause it to become disturbed, it is easy to send inhalable asbestos fibres into the air.
Insulated coverings for pipes and other plumbing components in old buildings may often contain asbestos. Before it was banned, insulators would wrap pipes with asbestos-based air-cell insulation; a type of cardboard designed from asbestos paper. As it ages, this type of insulation begins to crumble, releasing huge amounts of asbestos dust if it is damaged or disturbed.
Glueing a slab of insulation onto the wall of a building is a simple way to insulate. In the past, insulation blocks were a commonly used material and they were often made of almost pure asbestos. Although there is little risk to health if the blocks are left undisturbed, a block that is cut, damaged, or removed may crumble, releasing toxic asbestos fibres into the air where they can be inhaled.
Spray-on insulation tools were designed to minimise the amount of labour needed to apply insulation and other fireproofing materials to walls, structural beams, and ceilings. You may see it in large commercial buildings where the ceiling is coated with a thick layer of material. However, unfortunately, before the year 2000 many spray-on insulation products were made of up to 85% asbestos.
If you suspect that you have asbestos-containing insulation in your building, it’s best to contact a professional to safely remove it.