Forums > General Discussion   Shooting the breeze...

Caught in a bushfire - with no escape

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Created by Crusoe A week ago, 10 Nov 2019
Crusoe
QLD, 920 posts
10 Nov 2019 9:18AM
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Are there any methods to increase your chance of surviving a bushfire passing over you. I remember years ago seeing metallic blankets that firefighters could use to deflect heat if caught in a fire. Basically dig a bit of a hole and lay in it with the blanket pulled over. Are these practices ever successful or recommended. I see you can still buy different versions of these blankets. If they do work, then maybe people who stay to protect their houses in the event of a fire, should have them ready for deployment as part of their emergency Bush Fire Survival Plan.

Also we use to burn a block of cane with in 3 feet of another block of cane and were able to do so successfully without the fire spreading. The method was to basically to first burn a fire break between the 2 blocks of cane. This involved lighting 2 fires, the first was in about 4 rows from the block you didn't want to burn and the second fire was right on the boundary of the 2 blocks of cane. The 2 fires would draw togethers as you walked the flames along. This method was used for many years by cane farmers and it worked very successfully.

I was wondering if the idea could be adapted to saving your ar$e if you were caught in bush with no escape from a fire. Maybe light a fire in a spiral pattern where you slowly make bigger circles around your starting point. The fire would draw to the centre and once this burnt area was big enough to provide protection, you step back into it and wait for the main fire to pass.

Sounds risky I know and wind, different terrain and vegetation would have to influence the outcome. But the option of sitting on my ar$e and waiting to be burnt alive is not that appealing.

FormulaNova
NSW, 9522 posts
10 Nov 2019 10:58AM
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Doesn't the approaching fire itself create a huge wind, which spreads the fire quicker? I imagine trying to get a fire break started in those conditions could be interesting.

From what you read, it sounds like people are caught out trying to protect their houses which are attacked by embers. Some houses are well designed to survive this and some aren't.

Chris6791
WA, 3168 posts
10 Nov 2019 8:36AM
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Many of these fires are so hot you're asking the equivalent of crawling inside a crematorium and expecting a metallic blanket to save your arse.

TonyAbbott
286 posts
10 Nov 2019 9:00AM
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I believe there is lots of knowledge about this stuff but no wants to teach the public because of the extreme risk.

We are such a risk adverse society that the only advice given is to run early. This method is 100% successful.

If people had more of this knowledge they would they be safer? Or would more gamble




Crusoe
QLD, 920 posts
10 Nov 2019 11:12AM
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Chris6791 said..
Many of these fires are so hot you're asking the equivalent of crawling inside a crematorium and expecting a metallic blanket to save your arse.


Just wondering if you have read up on the blankets or is this your presumption.

FormulaNova
NSW, 9522 posts
10 Nov 2019 12:27PM
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Is this the type of blanket?

newatlas.com/sunseeker-fire-blanket/34442/

Mark _australia
WA, 19601 posts
10 Nov 2019 9:28AM
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No Chris is correct, he has been in some as have I

I have seen trees on fire with such ferocious heat that eventually other bush about 20m away on the other side of the road ignites. Not flying embers, as they are going much farther. Pure radiant heat. It is unbearable to stand 70-80m away.

They start to suck so much oxygen and make such heat that the fire starts to create 20kn winds that are like a furnace blast.

Thus burning a circle to stand in would be unlikely to work except in the smallest of fires without much heat or wind. Even then then will you handle the heat, smoke and possibly lack of oxygen?

The only sound methods if you live in the bush is to have all the gear, tons of water and pumps, no significant vegetation within about 300m of the house AND trust the authorities when they say its time to go

Chris6791
WA, 3168 posts
10 Nov 2019 9:36AM
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Crusoe said..

Chris6791 said..
Many of these fires are so hot you're asking the equivalent of crawling inside a crematorium and expecting a metallic blanket to save your arse.



Just wondering if you have read up on the blankets or is this your presumption.


I haven't read up on them but 7 years active service in a busy busy fire brigade and a further 20 years frontline emergency management. If I was crawling under one of those blankets I'd hope I also had enough charge on my phone to send some goodbye messages and tell someone where to find my remains.

Crusoe
QLD, 920 posts
10 Nov 2019 11:47AM
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Chris6791 said..

Crusoe said..


Chris6791 said..
Many of these fires are so hot you're asking the equivalent of crawling inside a crematorium and expecting a metallic blanket to save your arse.




Just wondering if you have read up on the blankets or is this your presumption.



I haven't read up on them but 7 years active service in a busy busy fire brigade and a further 20 years frontline emergency management. If I was crawling under one of those blankets I'd hope I also had enough charge on my phone to send some goodbye messages and tell someone where to find my remains.


Well, If I was caught in a bush fire and I had one of these blankets, I'd give it ago verse sitting on my ar$e waiting for the flames to melt my skin. The blanket might not work, but sitting on my ares and doing nothing, would have to have a worse result.

So from all your years of experience, what would you do in this situation (in the path of a bush fire with no means of escape), beside pull out your iPhone.

Chris6791
WA, 3168 posts
10 Nov 2019 9:51AM
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I never said I wouldn't give it a go...

Chris6791
WA, 3168 posts
10 Nov 2019 10:28AM
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I can't understand the specs on the net for thermal blankets, ISO and Australian Standards are a bitch sometimes, but I did lift this from a CSIRO report.

"The radiant heat flux from a thick bushfire flame can reach 100 kW/m2. By comparison, the average radiant heat flux from the sun at midday on a summer's day is about 1 kW/m2. The pain threshold for most people is about 2 kW/m2 and at this rate bare skin will undergo a partial thickness (2nd degree) burn in about 40 seconds. In the midst of a high-intensity head fire, radiant heat fluxes in excess of 150 kW/m2have been measured", "Inside the turbulent diffusion flames of a bushfire, the temperature of the reaction zone, where the volatile gases released from the thermally degrading vegetation mix with oxygen in the air and combust, can be in the order of 1600?C. The temperature of the flames themselves, however, is less than this adiabatic value, with the maximum temperature at the base of tall flames reaching approximately 1100?C due to mixing with ambient temperature air. The tips of flames are around 600?C."
I did find one basic set of specs for a crematorium and they're only required to top out at 870 degrees.

Ian K
WA, 3004 posts
10 Nov 2019 10:33AM
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Mark _australia said..
No Chris is correct, he has been in some as have I

I have seen trees on fire with such ferocious heat that eventually other bush about 20m away on the other side of the road ignites. Not flying embers, as they are going much farther. Pure radiant heat. It is unbearable to stand 70-80m away.

They start to suck so much oxygen and make such heat that the fire starts to create 20kn winds that are like a furnace blast.

Thus burning a circle to stand in would be unlikely to work except in the smallest of fires without much heat or wind. Even then then will you handle the heat, smoke and possibly lack of oxygen?

The only sound methods if you live in the bush is to have all the gear, tons of water and pumps, no significant vegetation within about 300m of the house AND trust the authorities when they say its time to go



You're contradicting a bit of bushfire science there Mark. Not that bushfire science qualifies as a particularly hard science. Can get a bit wishy washy at times. The trouble is carrying out and repeating experiments at anywhere close to the maximum intensity that fires can get to. But anyway...

Fires starting 20 metres ahead of the front would be attributed to short distance spotting. Often over-run by the main front before they develop.

Low oxygen would put the fire out before the people expire.

Yes burning a circle to stand in is not expected to work.

Australian bushfires need dry surface fuels to propagate. So you don't need to remove all the trees and shrubs from around a rural house. Just make sure the litter is under control. Green grass or bare dirt under trees is good. ( Apparently there are confers in Canada that hold enough dead fuel up in branches and are close enough together to carry fire even when the surface fuel is covered in snow.

Fire blankets and tents are better than nothing. Depends on the size of the clearing a fire fighter can find at short notice. None would work just thrown down in the forest litter. The US smoke jumpers carry them on their tool belt. They call them "shake and bakes" .



sn
WA, 2620 posts
10 Nov 2019 10:38AM
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Mark _australia said..
No Chris is correct, he has been in some as have I

I have seen trees on fire with such ferocious heat that eventually other bush about 20m away on the other side of the road ignites. Not flying embers, as they are going much farther. Pure radiant heat. It is unbearable to stand 70-80m away.

They start to suck so much oxygen and make such heat that the fire starts to create 20kn winds that are like a furnace blast.

Thus burning a circle to stand in would be unlikely to work except in the smallest of fires without much heat or wind. Even then then will you handle the heat, smoke and possibly lack of oxygen?

The only sound methods if you live in the bush is to have all the gear, tons of water and pumps, no significant vegetation within about 300m of the house AND trust the authorities when they say its time to go


same here.....
One of the disadvantages of our local Australian native flora [eucalypts and parrot bush] - is that the lovely things are full of oil.
The oil in the foliage boils out, and the tree is just waiting for the ignition point, and jeez do they explode!
Not an enjoyable feeling when we are on the back of a light attack unit [Tojo 4wd] with trees exploding around us, but at least it drowned out the UXO's, and lost ammo going snap crackle pop kaboom all around us.

note for anyone in fire prone areas - remove the plastic door mirrors on your vehicle and replace them with olde schoole metal ones - molten plastic really stuffs your paintwork

Toph
WA, 1473 posts
10 Nov 2019 10:44AM
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Fire blankets/tents like the ones these guys used

en.m.wikipedia.org/wiki/Yarnell_Hill_Fire

psychojoe
WA, 525 posts
10 Nov 2019 3:46PM
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TonyAbbott said..
I believe there is lots of knowledge about this stuff but no wants to teach the public because of the extreme risk.

We are such a risk adverse society that the only advice given is to run early. This method is 100% successful.

If people had more of this knowledge they would they be safer? Or would more gamble






Well, it's a lot safer if the fire chief doesn't turn off her phone and go to dinner. Nobody forgot Christine Nixon.

Wollemi
NSW, 312 posts
11 Nov 2019 3:01PM
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TonyAbbott said..
I believe there is lots of knowledge about this stuff but no wants to teach the public because of the extreme risk.

We are such a risk adverse society that the only advice given is to run early. This method is 100% successful.

If people had more of this knowledge they would they be safer? Or would more gamble






What are you on about? Care to share links to the 'lots of knowledge' ? Surely, with the official statements made for tomorrow for NSW, any thoughts shared may be valid.



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Forums > General Discussion   Shooting the breeze...


"Caught in a bushfire - with no escape" started by Crusoe