Reporter 432, 1 March 1999

One bump or two? Banging about with the deadly dust cloud explosions

Coffee and custard powder factories are being made safer by University researchers staging explosions big enough to bring down a building.

The fuel and energy department has what is believed to be the largest indoor explosion equipment of its type in the world, and is using it to study explosions of seemingly innocuous household materials.

"Many people are surprised that custard powder, aspirin and even tea can explode," said researcher Roth Phylaktou. "But factories making them face similar hazards to oil rigs and chemical plants."

The research team is working for a company developing dust explosion suppression systems. The technology detects the increase in pressure occurring milliseconds before an explosion takes hold and instantly floods the area with water or inert gas.

The controlled explosions are set off in huge pressurised containers and the researchers measure the speed at which the flame progresses - which can be up to 2500mph - and pressures generated.

Each explosion generates over a million measurements of temperature and pressure for analysis. "It takes a fraction of a second for the explosion, but it generates enough data for several weeks," said Dr Phylaktou.

The equipment is widely used to simulate explosions in the offshore oil and gas industry. By filling the tanks with methane gas and air and firing a spark plug at one end, explosions such as the one that crippled the Piper Alpha platform can be simulated.

"We analyse small and medium-sized explosions in different sized vessels," said Gordon Andrews. "This helps us scale up the explosive effects so we can understand the really big bangs."

The department's facility opened eighteen months ago and has attracted several interested visitors. "We don't know of any similar equipment in the world and we've had enquiries from the military, who were interested in building their own," said Professor Andrews. "And because we can depressurise the whole thing we even had an athlete interested in doing his altitude training inside. I'm not sure how comfortable it would be though, and anyway it takes about twenty minutes just to get the lid off."

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