That website is fascinating!

Thanks for posting the link.

I'm concerned with having air cool enough to breath. Keeping the soil cool is a different problem.


Melting ice is an exception. Convection normally rises but I don't think any other form of heat transfer prefers up or down.

If you were determined to build a shelter to protect you from wildfire I would stat with the simple bermed or underground shelters designed against aerial bombing, gas attack and firestorms.

The walls and ceiling are thick enough to stop blast and splinters should go a long way to being insulated and impervious to the forces fire bring. The ventilation systems of most shelters lacked filters because experience in WWI showed simple isolation was sufficient, far more reliable and cost effective than filters when facing an unknown contaminate. The external vents and doors were made to be gas-tight when shut down. The internal volume inside was calculated to be sufficient for the occupants for a few hours. Enough time for any agents to settle or dissipate.

This basic design concept, as shown by the military run shelters in Hamburg and Dresden, was sufficient even as a firestorm raged overhead. Unsealed shelters, typically basements, didn't fare as well. They provided good protection against bomb blast and splinters and fair protection against actual fire, they provided multiple escape routes and generally burned slow enough to allow sufficient time to evacuate, they were vulnerable to carbon monoxide and toxic gas buildup. Thousands of 'sleeping' bodies were recovered.

Further protection could be had by just keeping the shelter away from stands of trees and buildings that might burn and radiate heat, or potentially block the entrance, and limiting the amounts of flammable materials that reside on top of or near your shelter. Short grass or clover shouldn't be a problem as they would burn off quickly.

Yes, thank you Susan for that link. Those adobe shelters look great. Victoria's fire commissioner made a statement over the weekend suggesting country communities may have to look at building emergency bunkers.

Here's a link to the local effort at fire bunkers, mentioned in my earlier post:

http://www.illawarramercury.com.au/news/...es/1428913.aspx



It is all too late, and sadly, there is is bound to be opposition. But it seems ludicrous that there are no subsidies for bunkers in a country where the Federal government provides cashback rebates for solar hot water systems and home insulation.

I can understand the reluctance of fire and other authorities to sanction the use of bunkers when there is no building code to cover them. Unfortunately, even if authorities published a 'recommended' minimum standard of bunker they would, no doubt, be liable, should there be deaths.

Fire authorities point out that smoke inhalation has been a killer in some of the more amateurish bunker/shelters.

As of Monday, 16 Feb, the death toll remains at 181 with many still seriously and critically ill with burns and other injuries.

I think it is important to remember that these were firestorms, where 'ordinary' fire precautions were overwhelmed. Many deaths occurred when people stayed to fight the fires. These fires were spotting hundreds of metres in front of the main blaze; the temperatures were so high, 40-45C plus, before the fires even began, that homes simply blew up as the fires swept over them.

Peter, depending on government tends to be a waste of time and energy. The shelter I described is cheap. I just looked at one site that sells 250 sandbags for $123 USD. A roll of barbed wire, maybe $75 USD. With a shovel that most people have, $200 USD would probably build three 3.3 meter (10') shelters. Three families in a local area could share the expenses and the labor and build three shelters in a week.

People need to start working together. Governments are too stupid to depend on.

Sue