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A fire consultant has blamed foam plastic insulation for the fact that a half-constructed block of timber-framed apartments burned to the ground in nine minutes (page 22, 1 December 2006).

Peter Jones, an independent consultant to cladding products manufacturer Eurobond, which uses mineral wool insulation, said the spread of the fire would have been 鈥渄ramatically less鈥� if the insulation hadn鈥檛 been present.

Jones said the combination of plastic and a blowing agent used to foam the insulation meant it burned like 鈥渓ighter fuel鈥�, and explained the thick black smoke.

鈥淵ou can see thick black smoke in the pictures,鈥� Jones said. 鈥淪easoned, graded pine of the type used for the frame burns relatively cleanly; you don鈥檛 get thick black smoke. Hydrocarbons cause thick black smoke.鈥�

Seasoned, graded pine burns cleanly; you don鈥檛 get thick
smoke from it peter jones, Fire consultant

But Steve Cracknell, the fire investigator for the London Fire Brigade, said tests had shown that the insulation used on the project would not support a fire.

He said: 鈥淎s far as I can tell, it didn鈥檛 contribute to the fire as it has a flame retardant applied to it. The timber was the contributing factor.鈥� He lived near the development and said that he had found unburned pieces of insulation in his garden. 鈥淚f these had gone up in the flame plume, they wouldn鈥檛 have come down unburned.鈥�

Niall Rowan, fire test expert at Warringtonfire, said it was hard to say what contribution, if any, the insulation had made to the spread of the fire without knowing what the specific product was, as the flammability ratings of plastics varied so much. He added that the way the materials were arranged was more important.