WA bush firefighter spruiks shield prototype designed to keep crews safe in burn over

WA bush firefighter spruiks shield prototype designed to keep crews safe in burn over 

28 June 2015

published by www.abc.net.au 

Australia — It is simple, inexpensive, easy to make, and could possibly save the lives of bush firefighters across the country.

The Burn Over Protection Unit is the brainchild of inventor and volunteer bush firefighter Chris Probert, who lives in the small town of Denmark in Western Australia’s south coast.

Folded into a cabinet on top of the water tanks at the rear of a fire pump truck, the hi-tech heat resistant “tent” drops down over three people in a matter of seconds, providing a temporary protective refuge while a fire front passes.

It takes seconds for the fabric shield to deploy without need for motors, electricity or hydraulics to operate it.

The 67-year-old, who retired to Denmark after a life of designing and manufacturing as a mechanical engineer, became involved in his local Ocean Beach volunteer bush fire brigade four years ago.

Mr Probert said it quickly became apparent to him that fighting fires in dense bush on the south coast was extremely hazardous for crews at the fire front.

In October 2012, a Department of Environment and Conservation firefighter died from burns sustained when her fire truck was caught in a burnover at Two People Bay, east of Albany.

Burnovers occur in intense bushfires when a sudden wind change forces a fire over a fire line where crews are working.

Shock over death of firefighter Wendy Bearfoot

The death of Wendy Bearfoot and the injuries sustained in the fire by her colleagues shocked the firefighting community and triggered a raft of recommendations, including ways to better protect people caught in a blaze they cannot escape from.

Among the many measures recommended were deluge systems to douse the trucks with water, and roll-down heat shields in the cabs to reflect the intense levels of radiation, which can reach 1,000 degrees Celsius.

But Mr Probert remained concerned that sheltering in the cabins during a firestorm exposes crews to the toxic fumes given off by the melting plastics that line the roof, doors, floors and dashboards of the vehicles.

Plastic used in auto and truck manufacturing begins to melt at 200C and self-ignites at 400C.

“I quote a survivor from the Black Cat burn over incident in Two Peoples Bay when the guy said ‘I knew we were in trouble when the steering wheel began to melt in my hands’,” Mr Probert said.

He said the toxic gas from plastics contained cyanide, carbon monoxide, hydrogen chloride and dioxins, and were just as lethal as the heat from radiation.

“What we tried to do was create an alternative from staying in a cab which is full of smoke and plastic fumes,” he said.

Mr Probert put countless hours and his own money into creating the prototype refuge, which uses three layers of silica ceramic roller blind material designed to protect houses in Victorian bushfires.

He believes the shield can reduce a 1,000C peak outside to a relatively tolerable 50C inside.

“If you are on a fire ground and you’ve got a raging inferno around you, where are you going to go?” he said.

“Well, with the Burn Over Protection Unit, you do have somewhere to go.

“You get out of the cab and you get under the protection unit and not only are you safe from the radiation but you are in clean, fresh air, which will last a crew 20 minutes, certainly longer than a burn over.”

Former UWA head of physics contributed to design

Fellow Ocean Beach volunteer firefighter and former University of Western Australia head of physics Cyril Edwards contributed his considerable knowledge of how heat behaves towards the design.

Mr Edwards crunched the numbers to work out how many layers of the ceramic cloth and the air gaps between would provide sufficient control of the thermal energy.

“It’s essentially a very interesting but a very difficult physics problem, which is essentially how do you deal with a huge radiant flux from the fire front for a certain time, a few minutes hopefully as the fire front passes,” he said.

“[It’s] a system of three cavities basically. The outer one deals with the main thermal shock, then there’s a floating radiation shield and then there’s an inner wall of the cavity in which the three firefighters would stand.

“Because it’s a transient phenomena you have to design it so that the heat flux is integrated in the few minutes that you need to be in that burnover before you can escape.”

The initial reaction from the volunteers who gathered to view the operation of the prototype was positive.

“We’d much rather be in there than be in the truck or be in the cab,” one of them said.

“The idea of being in there as opposed to being in the cab with the fumes is certainly to be considered. It’s a really good idea.

“I think it’s the best thing since sliced bread. It’s going to keep us safe in the event of a burnover.

“It’s so simple, why didn’t you think of it before?”

Prototype made without support, funding

Firefighter Les Bains praised Mr Probert for taking his idea through to prototype, backing himself without any support or funding from the fire authorities.

“For an individual to come forward with that concept with the support of his fellow brigade members has been really, really good and I think it’s definitely got potential,” he said.

“He’s not been sanctioned by DFES or the Shire of Denmark, so all credit to him for going this far with it, and I hope he manages to pursue it.”

Chief bushfire control officer at the Shire of Denmark Graeme Thallon said he was optimistic, but cautious.

“For it to be used it would have to go through a lot of testing; obviously it would need the support of DFES to achieve that, so I think it’s very early days,” he said.

“The Shire of Denmark has not provided any funding at all or provided any assistance. DFES are aware [of the project] and they are interested in learning more about it.

“But it’s got to go through a lot of hoops to get further than that, before it can become officially sanctioned.”

But the next step for Mr Probert to convince the authorities his idea could work could be a tougher task than creating the prototype.

He will have to destroy his creation in a special CSIRO heat-testing facility in NSW to see if it will indeed withstand a bushfire and still provide enough protection for firefighters to survive.

“I can’t see why it wouldn’t work at the moment but the acid test will be to take a unit to take it to CSIRO and test it out,” he said.

“Prove the concept first and then see if the authorities want to run with it.

“We just want to see, does this work? Was this a good idea?”

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