Fire resistance of cellulose wool
The insulation contains the natural minerals – borax and sassolite (borates) that prevent fire effectively.
Carr, a New Zealander, used and studied the borates in the quality of fire protection for wood, materials containing wood, and cellulose, approximately in 1959, and after that their use has satisfied expectations
During a fire the borates first are dehydrated and then polymerized and go into a fire-resistant glass. They form a glass-like layer on the insulation surface that protects the inner layer of material against the air and heat leakage. A fire-resistant barrier is created on the insulation surface.
The amount of burned insulation is small because the burning action cannot reach the deep layers and stops on the surface.
The surface layer of cellulose decays and divides into the water and carbonic oxide. The toxic property of burnt gas is not significant.
The cellulose wool has a significant advantage over the syntactic insulation materials – the cellulose wool does not fuse and drop during a fire (absence of burning drops, which can cause burning the flooring), and does not extract asphyxiating gas and pungent smoke.
The experience shows:
if a metal thing is placed on the cellulose wool with a 40 mm layer (coin or plate), which is fused by a gas burner (t=1560 C), the molten metal cannot burn the insulation and moreover, a human hand cannot feel the high temperature.