A debate has broken out over whether the insulation used at a timber-frame construction site in Colindale, north London, was responsible for the rapid spread of a fire.
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 “dramatically less” if the insulation hadn’t been present.
Jones said the combination of plastic and a blowing agent used to foam the insulation meant it burned like “lighter fuel”, and explained the thick black smoke.
“You can see thick black smoke in the pictures,” Jones said. “Seasoned, graded pine of the type used for the frame burns relatively cleanly; you don’t get thick black smoke. Hydrocarbons cause thick black smoke.”
Seasoned, graded pine burns cleanly; you don’t 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: “As far as I can tell, it didn’t contribute to the fire as it has a flame retardant applied to it. The timber was the contributing factor.” He lived near the development and said that he had found unburned pieces of insulation in his garden. “If these had gone up in the flame plume, they wouldn’t have come down unburned.”
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.
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