Underground fireproof bunkers

[awg]

With what has happened in Vic, this thread might be relevant.

I personally own a remote rural block, surrounded by State forest.

I only have minimal structures at present, partially due to bushfire risk!

Does anyone have any knowledge or opinions about underground fireproof bunkers?

My idea would be to excavate a pit, waterproof and concrete surround, with a fairly thick earth roof ( at ground level), with a small fireproof trapdoor.

Ventilation would be by above ground steel flue pipe.

I am fairly sure that heat would not be a problem, but air quality may be.

I am almost certain that survive-abilty would be much higher than any other option, if you are trapped from escaping by fire.

When I build a permanent house, it will be rendered concrete block, steel, and gal roof, but I know gal roofs cannot withstand a really serious blaze,
( as evidenced by the footage from Vic).

I intend to do some research on the topic, so any tips would be good.

I believe many lives could have been saved if they had such an escape.

does anyone know what happened to persons in Dresden etc during firestorms, as they seemed to retreat to underground bunkers during bombing

 

[moXJO]

A lot of people just put a shipping container underground

 

[overit]

The bunker, dug into an earth embankment with 15-centimetre concrete walls and a $1000 fireproof door, saved their lives and that of their son, Raphael, 14 months. “It was like a firestorm, it was like a raging inferno. It’s a cliche, but that is what it was like,” Ms Berry said.

When flames engulfed their home they wrapped themselves in wet towels and sprinted to the bunker. “We couldn’t shut the door of the bunker, it was that buckled and warped,” Mr Berry said. “The embers were coming through the gap, it was like the fire was coming to get us.”

Nagging Wife Saves Family From Bushfire

 

[Happy]

My idea would be to excavate a pit, waterproof and concrete surround, with a fairly thick earth roof ( at ground level), with a small fireproof trapdoor.

Ventilation would be by above ground steel flue pipe.

Just heard discussion of couple of blokes about the subject.

They reckon, to be better protected from radiant heat there would have to be incorporated some kind of L - shaped several metres long corridor, between door and main secure area.
Best if door could have some heat proofing (sealed asbestos is great for that) and more than one set of heatproof doors preferable.

Fireproof Ventilation pipe should have S - bend in it too and fireproof non-return valve.

As to breathing air, few scuba diving bottles would be safer than pure oxygen bottles as sometimes pure oxygen bottle can all of the sudden be consumed by spontaneous combustion.

Also pure oxygen can start fire too even by mini-spark when light is turned on, computer game or similar.

(Apparently if during Oxygen bottle assembly somebody touches thread with bare hand, oils from skin, some time later oxygen can initiate spontaneous combustion, but I am not certain if this info is 100% or just some story)

 

[Ashsaege]

If i lived in an area surrounded by thick forest i would definitely invest in a fire bunker! make it bomb safe too!

 

[Ashsaege]

I reckon fire bunkers will start to become mandatory in certain areas.
Somebody might start up a business and make fire bunker kits.
They might start making them under water tanks too!

 

[ck13488]

with something like this you would employ the relevent engineering consultant to check over plans. if im going to stay on my property long enough, knowing my only means of survival is to lock myself in a concrete box i would want to be 100% sure that it wouldnt turn into an oven!

also i would build in an internal, self contained sprinkler system that would last for 10-15mins in the event of a fire...then again this may make things worse with humidity or even worse turn to steam!

if only engineering at uni involved some faint form of creativity id still be there!

 

[Whiskers]

If i lived in an area surrounded by thick forest i would definitely invest in a fire bunker! make it bomb safe too!

Yeah... but there also needs to be much better planning of these houses in bush/forested areas... maybe even local government/fire authority regulations... eg, it's just redicilous to me to build a timber house snug in timberered areas without some sort of serious fire protection.

Firstly, for me I would NOT build a timber house in those areas like in the above photograph. It would be steel, brick and concrete and even then I would have all trees cleared at least 30m away from house to give any chance of sprinkler system or other fire protection/fighting system a chance to work.

Maybe it's just me being born and bred in the country, but I always have a tank and drum water and firefighter pump available ready, and in my case slash or cultivate a margin around the house especially in the dry season.

Re bunkers... the above picture makes good use of a concrete water tank for a last resort bunker. One little extra that they could have included is a tap into their shelter to have some gravity fed water to keep blankets wet or at least to keep themselves wet and cool.

Also, I would get full concrete tanks, ie with a concrete roof, preferably with 100mm walls cast on site. That alone would provide a safe emergency shelter... that is, jump into the water in the tank and leave the concrete lid (usually square) placed diagonally across the opening to let in some air but still keep out any large objects from falling into the tank.

Just a couple of ideas that cost little but could mean the difference between survival or not of a fire storm.

Also, I wonder how many home and car owners have fire extinguishers in their home and vehicle. All too often a small fire from flying synders could be put out easily with a bit of preplanning and suitably prepared equipment.

But as I said, maybe it's just me, but I treasure what I have collected and always think about security including fire, tend to err on the side of caution and would rather spend some money on prevention than feel blindly assured that "I've got insurance".

 

[SevenFX]

Can't remember where I heard it but I beleive some farmers were smart enough it take shelter in the middle of their dam saving their lives, which may have ended up into a spa given they would have be surrounded by wall of flames.

Cargo containers seem a good idea provided setup properly.

SevenFX

 

[Glen48]

One bloke said he was in a Dam the water was cold below but he had to keep ducking his head under due to the heat, don't jump in to an above ground tank as they can boil in a F/storm.
Maybe look at USA and their bomb shelters.
Maybe some sign to let searchers know you could be in there, I would build away from the House and don't eat Bake beans if there is a hint of a fire.

 

[Glen48]

Even a shipping container covered with dirt above ground with a brick wall leading into it???

 

[wabbit]

I reckon fire bunkers will start to become mandatory in certain areas.

Making things mandatory does necessarily make them happen.

I would prefer to see it that all new homes in bushfire prone areas be manufactured from fire resistant materials (like the house near Bendigo(?) that survived the blaze when all the houses around it perished) (and be eco-friendly, but that is another soap-box for me to stand on later!) and each property shall have a fire break system around the boundaries (and where necessary inside the property boundaries on larger properties) and there shall be a mandatory clearing around the residence. In addition, each property shall be required to provide and maintain a water supply and pumping system for firefighting on their own property. There might be a lot of others measures that could save lives and property too, from fires in fire prone areas, and from floods in flood prone areas, and storms in storm prone areas, and cyclones in cyclone prone areas etc. People have been talking for years about climate change and its effects on the weather etc, but no-one seems to be doing much to combat the effects? All the talk is about the causes. Last-resort shelters and other systems might also be considered, but I believe a lot of preventative measures should be in place first. As the saying goes, "An ounce of prevention is better than a ton of cure."

These measures may seem draconian, but there are some councils in Australia where similar measures are already in place. Where my father used to live (near Northam, WA) very similar measures were required. But here is the key:

Whatever mandatory requirements are introduced (or maybe already exist?) they must be enforced. The requirements were my dad used to live were policed by the local council and volunteer firefighting brigade who reported back to the council. "Audits" or surveys were conducted quite regularly, I remember two visits from the council in just a couple of months. Failure to meet the requirements was a serious issue; large fines were (allegedly) regularly issued until full compliance was achieved.

I remember before a particularly hot summer in Perth some years ago, the head of the fire authorities in WA flew in a helicopter over the houses in the Perth hills and was exceptionally saddened/angry at what he saw: despite the warnings from the councils, fire authorities and the weather bureau about an impending bad fire-season and looming hot summer, many houses still had trees overgrowing their roofs, scrub up to the door step, no water on property and no means of pumping water without relying on mains power. Call it Murphy's Law, but just a few weeks later a fire raced through the area and many of the houses we had just seen mentioned were razed.

So how do we force people to do the right thing? (Why is necessary to need to force people to do the right thing anyway? To answer my own question, because "common sense" is unfortunately not that common, hence the need for laws outlawing the lighting of fires on hot, dry, windy days.) Making laws without enforcing them is pointless. Maybe the insurance companies should be the ones flying over the houses and making the surveys; people who don't comply have their fire-insurance voided until they meet attain full compliance? Is this the best answer? Don't know (probably not) but something has to get people to be responsible for their own lives and properties.

My heart goes out mostly to one man who was a CFA firefighter. He had done all the right things on his own property before the fire season started (clearings and water etc) but was out fighting the fires at another property (surrounded by trees and grass, on the wrong side of the slope on the hill, etc) when his own house burned to the ground. (I am sure there were more instances like this, but this was one report I actually watched on the news). Had so many resources not been required to protect the residence of someone too apathetic/lazy/stupid/whatever to do the work required to make his residence defendable against a brush fire, the firefighter(s) might have been able to be at their own places, defending them against the same blaze.

I am not sure a Royal Commission is going to resolve the issues either. I don't believe a Royal Commission is going to save lives should another bushfire start somewhere in Australia. All I think the Royal Commission is going to achieve is to listen to a lot of heart-breaking stories about how houses burned down and people died, and how under-resourced the firefighters are. I don't think there will be any useful outcomes to make self-protective measures mandatory and enforceable; it is an unfortunate part of our society today that so many people think all our ills and misfortunes are someone elses fault and someone else should always be responsible for the actions of others.

Too harsh? Maybe. But I hate seeing what should be taken as "a wake up call" be overtaken by knee-jerk reactions that have little long term benefit, or effects that are not remembered long after the emotion dies away. We all remember the ANZACS on ANZAC Day, but how many remember them the next day/week/month until the next ANZAC Day? The Victorian bushfires, however horrific, should be the impetus for some positive changes with long term benefits. Maybe some real changes can save some lives the next time some idiot starts lighting fires. (That's another soapbox for later, too).


$0.02

wabbit

 

[explod]

One small group sheltered and survived by huddling in the entry to a wambat burrow.

I grew up on a farm and was involved with fire prevention from an early age. As a country cop also a lot of experience (stony rises etc).

The main fire fronts move through quickly so an air vent is not required. Air within a reasonable sized bunker would be adequate for 10 of 15 minutes. Perhaps some form of periscope (retractible) could be handy and some bottles of water.

Out of this I think the government may come up with a standard for bunkers and increased education on individual fire planning. Housing materials and flammable material around homes is a further target.

 

[knocker]

How about a home made from shipping containers? Very cheap to make and pretty solid.

 

[saiter]

To everyone mentioning shipping containers: Since these are made from metal, won't they just conduct the heat and make it extremely hot inside, regardless of it being under or above ground?

 

[knocker]

To everyone mentioning shipping containers: Since these are made from metal, won't they just conduct the heat and make it extremely hot inside, regardless of it being under or above ground?

Yes you are right

 

[So_Cynical]

A small shipping container or even a mid sized Galvanized water tank fully buried
would be all that's necessary to survive a fire storm...u only have to survive the
10 or 15 minutes of the fire front.

Its the radiant heat that's the killer.

Earth/dirt is a super efficient insulator...in many big forest fires its common to bury
equipment that u cant move out of the fire line (bulldozers etc), but will need
operational after the front has moved through.

 

[Uncle Festivus]

An exposed shipping container would cook you alive, they are bad enough just on hot days. If you buried it you then get rusting?

I would be building a rammed earth house structure, with double glazed (small) windows to minimise exposure to radiant heat, gutter leaf proofing, along with the concrete tank and side building built below ground level or into the side of a hill or behind some sort of earthen wall as above, with the besser blocks filled with concrete, and concrete roofs to both tank & bunker also. I'm in the local RFS so from experience it's all about the radiant heat in the first instance, then it's maintaining the fire rating untill the fire front passes, usually 20 mins or so??

Not only would you have a house with good fire resistance but an excellent energy efficient house too. Perhaps this is what the law will now require?

 

[It's Snake Pliskin]

The only way is to head underwater or underground.

How about doing away with green policy and maintain backburning yearly, clearing around houses and understanding that humans occupy the land not rare tree hugging frogs with purple legs.

The aboriginees used to do back burning for the vegetation and soil.

http://www.2gb.com/index.php?option=com_content&task=view&id=5631&Itemid=134

 

[Whiskers]

Uncle, since you're in the RFS you might know what fire retardants are available to the public... eg something to add to water.

I use an agricultural wetter and spreader to get better effect from water sprayed on vegetation (mainly grass and undergrowth) immediatly ahead of a fire but have never enquired if there is anything else that we can use.

I suspect that many people wouldn't know a few little tricks to make a little bit of water go a long way to sufficate fires better.