OCTOBER 28, 2007 6:10 PM
TerraHertz said...
Saving your house from wildfires
Words from Australia, land of bushfires: If you leave your home before the fire front arrives, its 99% sure your house WILL burn down. Small spot fires in gutters, eaves, etc will get the whole house going pretty quickly. Without anyone around to put them out, its gone.
However, when people stay and follow a simple fire fighting strategy, its 99% certain their house won't burn. Here's how to do it. Note: Assumes you are fit, and can stay calm and act fast and sensibly in emergencies, and have prepared.
1. Preparation: You MUST remove all combustibles, shrubbery, long grass, leaves, etc from around the house. Clean gutters, block downpipes, fill gutters with water. Be aware the power will probably fail, and possibly the water as well. If you can get a hand pumped backpack water spray (one for each person who will stay), do.
2. Fill buckets, drums, baths, etc with water, and place around and inside the house well beforehand (water supply may fail at the critical time, remember?) Tie old sacks or blanket portions firmly to end of broomsticks, leave soaking in water. These are to beat out spot fires. A large axe, mattock, sledge hammer, spade, etc can be useful - keep inside the house near door. A cloth mask that fits over your mouth and nose, that can be soaked in water to filter smoke. If you have snorkelling goggles, keep them handy too - smoke that would blind you is no problem with goggles on - for as long as you can hold your breath.
3. Close all windows, doors (unlocked), if possible block up gaps under floor. Remove combustibles from inside vicinity of windows (curtains etc) since these can catch fire just from intense radiant heat from outside. If you can board up windows, even better. If time, paint with reflective paint - white, silver, etc.)
4. As fire front approaches, if you can, hose down roof, walls, windows, and grass around house. Forget about trying to save your garden, outbuildings, etc - you can't. If there is a lot of nearby fuel, and strong winds, best to hose down *inside* the house too. Damp belongings better than burnt belongings. At this point get your breathing mask, etc ready, and SOAK YOUR CLOTHES AND HAIR. Seriously - you want to be dripping wet. Just do it. Long pants and shirt - cotton or wool, not synthetics. Cloth that holds as much water as possible. Solid leather boots and gloves. Wet them too.
5. When fire front arrives (spot fires, trees near your house begin to ignite), go inside. Stay away from windows, keep all doors closed. You CANNOT stay outside during the 10 to 15 minutes of peak radiant heat. But your house will take longer than this to get burning. Use buckets, wet beaters, etc, to put out any fires that start inside. In the vicinity of the fire front the oxygen content of the air outside can get very low (another reason to stay inside - your sealed house has enough air to keep you OK for the critical few minutes.) If windows break, close off that room, retreat to hall.
6. As soon as conditions outside are tolerable again (see Risks below), get outside and do a rapid circuit of the building, evaluating threat priorities. You may need to just leave some small fires burning, while you deal with more critical ones. Use the wet beaters, save your water buckets unless absolutely needed. Use water or beaters on the *source* of the flames (the burning fuel), don't waste effort on the flames. Any fire that looks like it could get a foothold in the inner structure of the house is most urgent. Don't be afraid to smash open walls, etc if required. If there are large fires nearby, you may find that you can't take the radiant heat for more than a few moments, and have to repeatedly retreat to inside the house. This is why the soaked clothes, etc - it gives you longer outside. Keep re-soaking yourself, don't let anything dry out.
7. If the house does get burning too much for you to deal with, by now the surrounding fires have likely burnt out enough that you can walk away from your house safely. If you have managed to stop it from burning, whatever you do, *don't* leave it now. Stay with it until all nearby fires are well out, and there are no more wind-borne embers falling. Keep checking for small spot fires - any of which can still burn your house down if not dealt with.
----Risks----
Flare-ups and flame direction changes
During intense fires the local wind conditions get very unpredictable and powerful. The fire makes its own turbulent winds. One big risk to you is that columns of flame (say, from burning woodheaps, sheds, etc) can go from rising vertically one moment, to horizontal along the ground in a strong wind gust the next. Simple rule - observe how high the flames are going, and stay at least twice that distance away from the flame source. You do not want to be the moth in the horizontal blowtorch flame. Note that this rule implies you MUST NOT let yourself be caught out in the open in wooded areas by the fire front - which can approach at faster than the wind speed in high intensity fires. This is how most forest fire fighter fatalities occur - caught in open, plus sudden shift of flame direction, by fire-front that surrounded them in seconds.
Radiant heat
In intense fires where there is a lot of fuel on the ground and trees are igniting, fire propagation is via a front of radiant heat, that ignites (explodes is a better description) trees in series. When all the foliage on a tree is flash heated and bursts into flame at once, the radiant heat output is immense - enough to set fire in the same way to adjacent trees, ground litter, and even weatherboard walls. Personal exposure to this kind of heat will result in disablement and death. BUT... at any given spot in a forest or brushfire, the peak of radiant heat will only last a few minutes - usually less than five. Almost any shelter that completely covers your body, has reasonable heat-absorbing mass (walls, wet blankets, etc) and shields you from wind-blown flames will be sufficient. Note that vehicles are not good as shelters - thin metal skins heat up too quickly, everywhere inside is too exposed via the windows, and everything in the car will burn quickly, plus generate toxic fumes.
Suffocation, smoke blinding, panic
Around the fire front the air can be unbreathable for minutes at a time - choking smoke, and/or reduced oxygen levels. Smoke may also be too thick to see anything through. If you are outside the contained air in a building in this interval, you can lose consciousness, or be incapacitated by coughing, blinded eyes or poor visibility, lose your orientation, and/or become panicked. Any of these can kill you, since you may then be caught exposed to the flames and heat. This is why you must stay inside the building till the outside fire peak is over. If the building is catching fire too, thats too bad. Just close doors to the burning rooms, and wait just inside the best door to exit, for as long as possible.
Underground burning cavities
Many people are unaware of one big risk after forest fires. Large tree roots and stumps can remain burning close under the surface of the ground for days afterwards. Its possible to be walking along, and the ground to give way under your foot, dropping a leg into a red hot furnace. Its best to NOT go walking in recently burnt out forest areas.
Emergency shelter
If trapped away from buildings, in bushland/forest by a strong fire, your options are limited. You must either; * Find something underground- a fully enclosed cave, or deep crevice in rocks. In urban areas or along roads, stormwater drains or culverts can suffice. * Find a pool or watercourse where you can fully immerse yourelf. As far from combustibles as possible, to minimise chances of losing consciousness from smoke/oxygen depletion during the fire peak. * Find a large open area, at least several hundred feet diameter, with little burnable ground cover. Stay low, in the center. Cover yourself with whatever you can. If the ground is sandy, dig in. * Failing those, your only fallback is to backburn a clearing for yourself. Only do this as a last, lifesaving resort.
'Authorities'
Given that the local authorities are likely to try and forcefully evacuate you (thus virtually guaranteeing your house will burn down), one has to count them as perhaps the greatest threat you'll face. I've actually had the experience of helping save a neighbour's home situated in bushland, where both of us had to evade the 'fire brigade' *and* local military forces deployed to evacuate residents. They came to the property long before the fire arrived, took away everyone they found, then left. Not wanting to risk getting their nice shiny fire truck singed or dirty. He'd hidden nearby, and I arrived (via the riverside bush, not the road) just before the fire front. As described above - barrels of water around the house, wet-sack beaters, soaked clothes, stay inside house during the peak, then get out and fight... And despite there being lots of nearby combustibles (very spectacular), the old, rambling wooden house was saved. The 'firebrigade' returned on their still shiny truck about 45 minutes later (when it was 'safe' for them) and made a show of hosing down a nearly burnt-to-the-ground pergola nearby. Thanks a lot, heros.
So, with this in mind, what you need is a good hiding spot. When it looks like the authorities will show up, hide. Have any household members who can't help firefight leave with the authorities, and say there's no one else home. If you are alone, or everyone is staying, decide whether to leave your house locked up or open, depending on what kind of arseholes your local police/etc are. Would they break down doors to 'check no one is home'? Your call. Be aware that in some circumstances, these 'friendly local authorities' may actually *want* your home burnt down, in which case its best they don't see your preparations to stay and firefight. Once the fire approaches, these cowards will be gone. You might consider, if you have any doubts about the motivations of your public officials, secretly videotaping their actions while on your property. Who knows - maybe they try to make *sure* your place burns down? In which case you'd be justified in shooting them, if you are armed. And a video of their actions on youtube would be a useful warning to others, not to mention for your own defense.
In general, as is usual in these days of government gone haywire, you are on your own. Those who you should be able to count on for help, are more likely to be your active enemy.
TerraHertz
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