Fires involving insulation materials Firesafe Rockwool stone wool helps stop fire Rockwool insulation saves house on fire (Oslo, Norway, 1995) 30 minutes of intense fire in the kitchen. Luckily, the firesafe Rockwool insulation in walls and roof prevented the fire from spreading to the rest of the timber house.  Read more... In case of fire, the choice of insulation material can become a vital issue in terms of casualties, material or environmental damage. Rockwool insulation is non-combustible and withstands more than 1000°C. It can act as a fire barrier. Combustible insulation on the other hand can fuel the fire and cause it to spread. Some of the most widely used combustible insulation materials are oil-based foamed plastics (eg. polystyrene, polyurethane or polyisocyanurate) and organic materials (eg. shredded paper/cellulose). This supermarket burnt down completely.