STEEL producers have defended criticism of the material's fire performance after a devastating fireball swept through a Spanish tower block last month.
Reinforced concrete industry representatives claimed the fire that destroyed Windsor Tower in Madrid last month showed the weakness of structural steel under fire conditions and that this poor performance had caused the structure's partial collapse.
They pointed to the collapse of the steel perimeter columns as the cause of the failure of the floor slabs during the 19-hour fire. They also claimed a massive concrete transfer slab on the 17th floor of the 32 storey block helped prevent further progressive failure, underlining concrete's inherent strength under fire conditions.
Steve Elliot, project director of the British Association of Reinforcement, said: 'The internal reinforced concrete core withstood the fire and appears to have remained structurally sound.The same cannot be said of the perimeter steel columns and beams which dramatically failed despite having some fire protection.This resulted in the partial collapse of the tower.'
But Roger Steeper, product development manager at steel producer Corus, called Mr Elliot's claims 'tenuous' He said: 'The fact is that no one is entirely sure what happen and the results from the enquiry will probably not be ready for another 12 months or so.What is inescapable is that the Windsor Tower is a concrete frame building and it partially collapsed.'
He defended the performance of steel-framed structures, citing a programme of full-scale fire tests at BRE's Cardington base as helping to prove the performance limits of steel under fire.
He said: 'Steel has gone through a complete regime of full-scale fire testing to prove its performance levels. A similar series of full-scale tests on a concrete structure was halted after the shocking performance of reinforced concrete in just one, incomplete, test.'
nMore than four times as many multi-storey buildings in the UK are built using steel than reinforced concrete, says a report from Corus.The steelmaker's latest market shares survey shows that almost 70 per cent of multistorey buildings in the UK were built using steel compared with less than 17 per cent using reinforced concrete.
Load-bearing masonry had a 9.5 per cent market share with precast concrete and timber accounting for 2.8 per cent and 1.7 per cent respectively.
Corus Construction marketing general manager Alan Todd said the figures showed steel price increases had not affected its competitiveness.