Non-Asbestos Fibre materials are so-called because they fill the gap in the range of gasket materials previously occupied by asbestos. Asbestos, although considered to be a dangerous material, had excellent heat resistance properties, which is why it was utilised so widely in high temperature applications. When asbestos was outlawed, replacement materials were needed; so these asbestos-free, or non-asbestos, materials were developed to perform the same function, but without the corresponding problems.