BRITAIN RISKS a skyscraper blaze like the one which devastated Madrid's Windsor tower last month because of fl ws in British Standards, a leading manufacturer of fire stops warned this week.
Fire stops can delay the spread of a blaze between the floors of externally clad multi-storey buildings.
Manufacturer Hilti claims that British Standard BS8414 is flawed because it can be met without testing cladding and fire stop systems in a real fire.
The standard assumes that external cladding systems retain their shape in a fire.
In Madrid, intense heat inside the Windsor Tower caused the cladding to bulge outwards, which would have allowed any fire stops present to drop out within 30 minutes. Flames spread through gaps between floor plates and cladding.
Most firestop systems used in the UK, including some made by Hilti, are mineral wool pads, friction fitted between floor slab and curtain walling.
'A lot of buildings are at risk, ' said Hilti fi re stop product manager Rebecca O'Reilly.
'Madrid has highlighted clearly the problems in Britain.' Hilti is pressing the Office of the Deputy Prime Minister to change the British Standard to recognise that curtain walls bulge in fires. But it needs to get curtain wall manufacturers to admit that their products move.
A spokesman for the Metal Cladding & Roofing Manufacturers Association said that building research body BRE was fully aware of the issue and had carried out tests.
He said the main concern in the UK was with the performance of windows, not curtain walling. Hilti has developed a spray system which expands to accommodate 15% joint width movement in a fire.