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Flawed fire tests put lives at risk


Sir, I TAKE great exception to the conclusions reached by Mr Robinson of British Steel, reported in your article 'Steel fire protection 'outdated'' (CN September 30).

His remarks are based on tests carried out at the Fire Research Station at Cardington. He suggests they show that steel structures can withstand far higher temperatures than previously thought.

But the tests were carried out in a way that does not reflect the way in which we fire protect buildings in the real world.

Both structural and compartmentation fire protection is required to protect a multi-storey steel framed building adequately.

In the Cardington fire test, the fire fuel (office furniture) was only in the test area. There was no fire fuel in adjacent 'offices' or on floors above. If a fire resulted in the levels of structural deflection witnessed at Cardington, the effects would have been as follows:

As perimeter beams deflected, the fire stopping system between the edge of the structural frame cladding system would have been breached, allowing the fire to travel upwards to the next floor.

Once interior beams started to deflect, as was seen at Cardington, the deck above would drop, causing crushing and failure of the firewalls and a breakdown of fire compartmentation. This would allow fire to spread sideways through the building.

Once the fire had spread in this way, its duration and intensity would increase, due to the extra fire fuel.

Few, if any beams would not be affected and the likely scenario would be collapse of the entire edifice.

Premature collapse of the structure would put at risk not only the lives of the occupants but also those of the fire service and other members of the public.

Hence, the conclusions reached by Mr Robinson are dangerously misleading. In real fires containment of a fire to the room of origin only occurs by structural and compartmental fire protection.

The risks run by building structures based on such inaccurate information are potentially immense.

David Harper

Fire Safety Development Group London SW1