The vacuum extinguish method for cleanroom fires

The new method has been designed to replace traditional CO2 extinguishers, sucking rather than blowing a fire out

Left: Without suction operation    Right: With suction operations
Credit: Toyohashi University of Technology

A team of researchers from the Japanese Toyohashi University of Technology’s Mechanical Engineering Department has approached fire safety from a new direction. The new vacuum extinguish method sucks as opposed to blows a fire out.

The technique has been designed to replace the use of CO2 in space vessels, but the same benefits would apply to submarine and cleanroom environments.

CO2 has always been used as it does not eject materials that could cause the complex systems in place to malfunction, which in the setting of space could be highly dangerous. However, the leftover gas in the enclosed space can be harmful to humans, so scientists are always keeping their eyes out for a better way.

The new method is driven by the pressure difference between the suction box and the room. The flame and the combustion products, including the source of fire, are sucked into the vacuum chamber to stop combustion.

Once the fire is extinguished, the suction valve can then be closed. The chamber can then be cleaned out and de-pressurised for reuse.

To test the fire extinguisher the scientists used a small scale electric wire with a polymer sheath, subsequently publishing a paper showing their successful results.

Many more safety checks and approvals need to be done before the system can be commercialised, but the preliminary results seem promising.

Cleanroom fires can be hugely costly, not just in direct costs, but also in stopping production lines. To add to the difficulties, fire safety products often need to be specifically designed to be suitable within the controlled environment, such as fire curtains that can exist in the air cleanliness settings. This method may prove hugely useful in mitigating these losses for companies from a fire in their facility.

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