The KMF are industrially produced artificial mineral fibres. There are four groups: glass wool (white or yellow long fibres), rock wool (darker, green-yellow fibres), slag wool (dark, brownish fibres; not very common) and ceramic fibres (white; high-temperature wool).
The KMFs were and are primarily used for heat and sound insulation (e.g. in roofs, ceilings and walls, in ventilation and heating systems), partly also as a substitute for products containing asbestos. KMF produced before 1996 are called "old mineral wool". These can release respirable fibres with low biodegradability and are therefore classified as carcinogenic. After a transitional phase, only biodegradable mineral fibres with the RAL quality mark have been allowed to be placed on the market since 2000.
Mineral fiber products
KMF in old fire door
Roof insulation from KMF