BS:Building in Fire prone areas - 2009 fire season

Subject: BS: Building in Fire-prone areas
From: Sandra in Sydney
Date: 24 Aug 09 - 02:58 AM

A man who lost his home in the 2003 Canberra bushfires (4 dead, 520 homes lost) has built a fire-proofed home The story has links to other articles on the recent 2009 fires

BS: Bushfires in Australia - Feb 2009

sandra

Subject: RE: BS: Building in Fire-prone areas
From: Nessie
Date: 24 Aug 09 - 08:57 AM

Interesting, but you wouldn't want to see too much of suburbia paved over with no native trees. Were we still living in Greece at the moment we'd probably be heading back to Dionysos to see if we had a home left, so I can understand him wanting to fight it. Hope he doesn't have to put it to the test.

Subject: RE: BS: Building in Fire-prone areas
From: Rapparee
Date: 24 Aug 09 - 09:18 AM

Diesel or petrol pumps for the water....

It's gonna get AWFUL hot inside that place if there is a fire. The windows will shatter if they get hot enough or if water hits the hot glass.

It might be fireproof construction, but the interior can burn like Hell in high wind.

I hope he's planning to evacuate when a fire comes again. I would hate to be inside when the oxygen is sucked out and his "air supply" explodes in the heat.

Subject: RE: BS: Building in Fire-prone areas
From: Leadfingers
Date: 24 Aug 09 - 02:32 PM

In UK , thankfully , we dont have many fires threarening the suburbs , but we DO have a ridiculous number of new properties built on flood plains !! Maybe they should get Noah in as a consultant architect ?

Subject: RE: BS: Building in Fire-prone areas
From: Bill D
Date: 24 Aug 09 - 02:56 PM

In the US we have fire areas, flood areas, coastal Hurricane areas, landslide areas, etc...ALL of which should be under tight regulation about both where to build and types of buildings. (Tornado areas are almost impossible to legislate about...people do have to farm and live there.)

Fire is hard to deal with, as Rapaire points out, as enough prolonged heat can make almost any building unlivable. I suppose with all those features, he will be reasonably protected against all but the worst.

Subject: RE: BS: Building in Fire-prone areas
From: Peace
Date: 24 Aug 09 - 04:06 PM

The house may be 'fire proof' but the contents aren't. And the diesel (or petrol--use diesel because it's less flammable) motor to run the pump is the weak link. Beautiful house, though. Best wishes to the builder/owner.

Subject: RE: BS: Building in Fire-prone areas
From: Peace
Date: 24 Aug 09 - 04:11 PM

Sorry, Rapaire. Hadn't read your post. My apologies.

Subject: RE: BS: Building in Fire-prone areas
From: Rowan
Date: 24 Aug 09 - 06:54 PM

Diesel or petrol pumps for the water....
The main problem with petrol as a fuel for machinery involved with firefighting is that petrol vapourises at a lower temperature than diesel. This caused the death of the Cockatoo crew in the Dandenongs part of the Ash Wednesday fires of 1983. Their fire truck had a petrol motor and, when they stopped on a fire trail to check on the approach of a fire the motor was turned off. The petrol in the fuel line vapourised and created a gas lock, preventing liquid fuel from reaching the carburettor and getting the vehicle started. Following a recommendation from the subsequent Royal Commission, all CFA vehicles (and their pumps) commissioned since then have had only diesel as fuel. The fact that diesel motors use liquid fuel injected into the combustion chamber (rather than relying on a vapour fuel) helps.

It's gonna get AWFUL hot inside that place if there is a fire. The windows will shatter if they get hot enough or if water hits the hot glass.

It might be fireproof construction, but the interior can burn like Hell in high wind.

I think your man has covered those contingencies with his metal screens fitted over the doors and windows. Of course, he has to be there to fit them but, from the report, I gather he is close to retirement age.

I hope he's planning to evacuate when a fire comes again. I would hate to be inside when the oxygen is sucked out and his "air supply" explodes in the heat.

I may be misinterpreting Rapaire's gist here but the notions that houses have the air sucked out of them and explode need some clear thinking applied.

People's accounts of their houses exploding were carefully investigated after the Ash Wednesday (and subsequent) fires; almost all involved a window (usually a large one) directly exposed to the flame front. Most of a room's contents are flammable and plastics (you'd be surprised how much plastic there is in most houses) vapourise under intense radiation coming through windows. With a superheated vapour/air mix in the room it only takes a small ignition source (often a spark through a ventilator or the glass breaking) and you have sudden conflagration of the mix. It seems like an explosion. It is also the only circumstance where "oxygen is sucked out" of a house that isn't densely surrounded by other built structures (vide Kurt Vonnegut's experiences in Dresden).

Your man's house is relatively isolated and I suspect his bunker with its air tanks is located where it would be relatively cool.

Cheers, Rowan

Subject: RE: BS: Building in Fire-prone areas
From: Joybell
Date: 25 Aug 09 - 07:06 PM

I'm with Nessie. Concrete doesn't burn. Living in a paved and cleared human habitat is a good way to avoid bushfire.
I saw the comments of a man who lost his home on "Black Saturday". He said he had 91 acres of cleared land with only one tree but his home still burned because of the native vegetation around the property. Where exactly is the forest with its complex ecosystem going to be allowed to be? We've taken so much already. Even Victoria's native grassland is all but gone and the last remnants are about to be taken over by suburbs.
Is there nobody else who notices the absence of a "dawn chorus"? The sharp decline in bird populations. Even the decrease in road kills -- much as that looks, on the surface, a positive.
Of course if we get rid of all the wildlife -- plants and animals they won't burn will they? That's what people tell me. Silly me to not see that. We will still have humans and their chosen animals and plants.
All my thoughts, Nessie.
Joy

Subject: RE: BS: Building in Fire-prone areas
From: Art Thieme
Date: 25 Aug 09 - 07:48 PM

"They paved paradise and put up a parking lot!" -- Joanie Mitchell

This irony laden value judgment has become, with the passing of time, a rather profound prescription for how to protect some areas from these conflagrations.

Art Thieme

Subject: RE: BS: Building in Fire-prone areas
From: Rapparee
Date: 25 Aug 09 - 09:32 PM

I don't know what "metal screens" mean in Oz, but here in the US they are a wire gauze used to keep insects out and let breezes in. If they are solid we'd call them "metal shutters".

As for oxygen depletion...I stand by my statement as long as firefighters wear SCBA.

Subject: RE: BS: Building in Fire-prone areas
From: open mike
Date: 26 Aug 09 - 12:33 AM

some fire engines have been known to stop running
because the atmospheric oxygen was depleted by the
fire and the motor had none for the carburator to
mix with the fuel. firefighters have become trapped
without the possibility of escape due to this.

around here the homeowners are cautioned to clear all
vegetation 100 feet from the house--they used to say
30 feet...but regs. have changed. this includes ladder
fuels--ones that would allow a fire to climb from the
ground to the crown (tree tops) unfortunately we have
60,000 acres of trees burned last year, and still there
is fire danger from standing dead timber--cooked by the
sun for a year, and may topple from wind.

Subject: RE: BS: Building in Fire-prone areas
From: Rowan
Date: 26 Aug 09 - 12:47 AM

Where exactly is the forest with its complex ecosystem going to be allowed to be? We've taken so much already. Even Victoria's native grassland is all but gone and the last remnants are about to be taken over by suburbs.

Over the years I have observed, with considerable sadness, that many Australians are really still Europeans when it comes to "attitudes" about many aspects of the environment. "The only good snake is a dead snake" is still widespread, although research in western NSW wheat lands indicates that one brown snake will save the grower about $5000/year (2001 values) with its control of mice populations. I once did a bit of a survey of farmers, showing them photos of various landscapes with different levels of pasture and clearing; most regarded the the ones with the appearance of a classic English park (grass with only one or two trees/acre) as the ideal landscape, irrespective of where in Oz they happened to be.

Bushland generally, and forest particularly, seem to invoke feelings of "threat" in many people. This is in stark contrast to the escapees from inner city living following their "tree change" desires. All too often they'll ensure flammable eucalypts are right next to the house. The hamlet near where I live has 350 households in such an environment, most in uncleared country with ridges and gullies facing the prevailing westerlies and with access driveways too narrow to get a Cat. 1 Isuzu fire truck anywhere near the house.

And, because the local govt (equivalent to UK's Shire Councils or USA's County Councils) is dominated by real estate developers who wish to maximise personal profits and minimise their land contribution to roads, we have lots of cul-de-sacs that are guaranteed to entrap evacuees.

Sigh!

Cheers, Rowan

Subject: RE: BS: Building in Fire-prone areas
From: Rowan
Date: 26 Aug 09 - 01:00 AM

I don't know what "metal screens" mean in Oz, but here in the US they are a wire gauze used to keep insects out and let breezes in. If they are solid we'd call them "metal shutters".

Sorry, Rapaire. I didn't get to see your latest post before sending my previous bit in. Gauze screen (whether wire or plastic) in Oz are routinely referred to as "flywire"; the metal screens your man is using appear to be what you'd call shutters.

The main use of CABA (as it's called in Oz) by firefighters (again, in Oz) is to provide a breathable atmosphere while inside smoke- and fume-laden atmospheres such as you find inside a burning structure. The local town brigades across NSW maintain they have an average response time of 4 minutes. Research here indicates that, within 2 minutes of a flame appearing from fuel that is smouldering, atmospheres inside a structure will become toxic from vapourisation of flammable materials; plastic degrades to produce cyanide and hydrochloric acid fumes, and any hypalon exposed to such temperatures can produce hydrofluoric acid. None of these is good for one's health, which is why evacuation drills specify completion within 90 seconds; it's also a good reason to wear CABA if you must enter such atmospheres.

Cheers, Rowan

Subject: RE: BS: Building in Fire-prone areas
From: Peace
Date: 26 Aug 09 - 01:12 AM

It's called SCBA in Canada. We use 'air on demand', and subsequently insist that everyone be able to accomplish a perfect seal between facemask and skin. NO leaks.

Further to what Rowan noted, fire doubles in size every 30 seconds. It cannot be stressed enough that one should get out and stay out.

The materials inside structures are indeed so toxic that we even insist that for 48 hours after a fire people entering what's left of the structure wear SCBA because the toxic effects can last that long, even in well ventilated places.

We have LOTS of urban/forest interface here, and despite best efforts to get folks to cut the brush back from their houses people still insist on that 'country living' feeling. But we try.

Subject: RE: BS: Building in Fire-prone areas
From: Rapparee
Date: 26 Aug 09 - 09:21 AM

Yeah, Bruce. Here too. So far this year we've been damn, damn lucky.

Subject: RE: BS: Building in Fire-prone areas
From: Joybell
Date: 26 Aug 09 - 05:57 PM

*sigh* from me too, Rowan.
Thank you Mudcat for giving us somewhere to meet and share our thoughts. There are so few places those of us, with a love of the natural world, can do that. Australians anyway. We feel under siege. Overwhelmed.
Joy

Subject: RE: BS: Building in Fire-prone areas
From: JohnInKansas
Date: 26 Aug 09 - 11:53 PM

The article on the "fireproof house" implies that the builder relied largely on "common sense" methods in selecting features to include (and exclude). Although it takes a little work to dig out the details, if any of our own need help with reduction of fire threats, a place to start could be http://fire.nist.gov/.

A fairly common slip is building a fireproof (fire resistant) structure and then filling it with flammable furniture and other contents. Classic illustration, from a link at the above: watch the first video and have a merry Xmas. (Note that the TV set goes in about 35 seconds.)

John

Subject: RE: BS: Building in Fire-prone areas
From: Rowan
Date: 27 Aug 09 - 06:31 PM

Good stuff. And, to be fair to your man, he didn't claim his house was "fireproof"; all he claimed was that it was "fire resistant" to the best of his ability. Given the public awareness of research on structural resistance to ember attack (fairly extensive after Ash Wednesday 1983, and fairly extensively ignored until after Canberra's 2003 holocaust) it appears he's done better than most.

Cheers, Rowan

Subject: RE: BS: Building in Fire-prone areas
From: Rapparee
Date: 28 Aug 09 - 09:11 AM

And embers are the reason that last year I spent US $15,000 to replace a roof of old, dry cedar shakes with one that is rated as highly fire and wind resistant.

As my brother Tony said in another context, "I can't stop 'em, but I can sure try to slow 'em down."

Subject: RE: BS: Building in Fire-prone areas
From: The Fooles Troupe
Date: 28 Aug 09 - 11:29 PM

"Concrete doesn't burn"

Ahh... but a concrete structure, once inside a good conflagration is seriously weakened, as is a brick and mortar one. Often to the state of being structurally condemned as prone to fall in the wind...

You MAKE cement by heating, driving the CO2 out of the chemical that it sets to when wet and used as mortar... :-)

Subject: RE: BS: Building in Fire-prone areas
From: John on the Sunset Coast
Date: 29 Aug 09 - 10:25 AM

Here in Southern California it's like an Anita Carter song, "Ring of Fire". About five miles east of us, in the foothills of Los Angeles, is a major fire. It's snowing ash on the house. About 10 miles of east, in the extension of the same foothills is another fire. Almost directly south of us, but not close, in the Palos Verde Penninsula, overlooking the ocean is a third fire. Finally about half way between Palms Springs and San Diego is a fourth fire. All of this coupled with temperatures hovering around 100+ degrees.

The fortunate thing is that there has very little wind so that each of the fires has not grown at alarming rates. Other than really bad air, the damage to humans is minimal. I'm not sure any structures have been damaged, save a few shacks far from populated areas. I'm not so sure the effect on wildlife has been so benign, but one can hope.

Subject: RE: BS: Building in Fire-prone areas
From: Sandra in Sydney
Date: 29 Aug 09 - 11:49 AM

may the California winds continue to be light.

We've had a very unseasonable August with high temperatures around the country & also strong winds in some places, so we have an early start to our bush fire season.

Residents warned to stay as blaze menaces homes

sandra

Subject: RE: BS: Building in Fire-prone areas
From: Sandra in Sydney
Date: 30 Aug 09 - 03:45 AM

photo - Flames burn along a ridge in Los Angeles

Australia - South coast fire 'unpredictable' amid winds

Subject: RE: BS: Building in Fire-prone areas
From: Joe Offer
Date: 30 Aug 09 - 11:26 PM

There were about 30 homes lost in my area (Auburn, California) this afternoon and evening - only about 275 acres, but fairly densely populated. I could see the smoke from about 15 miles away and got within two miles of the fire on my way home. The smoke was intense, but hasn't spread as far as I expected. My home is 10 miles northeast of the fire. I could see a lot of smoke at 5 PM, but very little at 8 PM.
I'm trying to find out if any friends lost their homes. So far, none. I was particularly concerned about a friend who lost his 19-yr-old son in June and totalled his car in July. He lives very close to the fire, but I think he's OK.
There's a retirement home in the fire area that I visit, and I haven't been able to find out if it escaped the fire.
Close, but we're safe. Makes me wonder how safe we are, since we have a lot of dry brush and trees in our area.

-Joe-

Subject: RE: BS: Building in Fire-prone areas
From: Peace
Date: 30 Aug 09 - 11:37 PM

"The evacuation zone is approximaely seven miles long in the path of the fire which is now travelling north away from the city of Auburn."

Subject: RE: BS: Building in Fire-prone areas
From: John on the Sunset Coast
Date: 31 Aug 09 - 12:15 AM

I was a little previous in my prior post. About six hours after I wrote we were notified to evacuate. We came back mid day Sunday, but we may have to leave again sometime Monday. God willing we won't have to.

I think I read that 42,000 acres+ has been burned. The mountain containing most TV/Radio transmissions is like to be taken over by fire. One fire is out (pretty much), but another popped up about 40 miles east. Truth to tell, we're pretty apprehensive, but better prepared if we must leave.

A good thought would be nice.

JotSC

Subject: RE: BS: Building in Fire-prone areas
From: Peace
Date: 31 Aug 09 - 12:36 AM

John: Have they given instructions as to what you should take with you? (Medications, etc?) Man, I'll be worried now.

Subject: RE: BS: Building in Fire-prone areas
From: Joe Offer
Date: 31 Aug 09 - 12:59 AM

I'll keep you in my thoughts, John. As I drove home from the grocery store today, I kept wondering if it was my area that was burning. You can see the smoke from many miles away, but you can't tell where it is.

The fire in my area was relatively small, 275 acres, but it hit a housing tract that was almost completely destroyed. The fire started almost a mile away from the area of worst destruction. I still don't know if I have any friends who lost their houses. I think that's a phenomenon of rural areas - we see each other in town all the time, but never visit each others' houses and don't really know were people live; but yet we feel we know these people very well.

-Joe-

Subject: RE: BS: Building in Fire-prone areas
From: Sandra in Sydney
Date: 31 Aug 09 - 02:30 AM

the northern hemisphere summer fire season hasn't yet ended while the southern hemisphere summer fire season is starting early.

Best wishes to Joe & John & families & friends.

sandra

California - Two firefighters die in LA wildfire

Australia - NSW fires: crews strengthen containment lines

Subject: RE: BS: Building in Fire-prone areas
From: Rowan
Date: 31 Aug 09 - 03:01 AM

All the best to both you and yours, the two of you. I'm not sure whether Oz advice is of much use to you Joe but, I'd keep a couple of woollen blankets (none of your acrylic or blends, or even cotton)in the car if I had to drive anywhere when fires are in the offing. And a pair of leather gloves under the driver'seat.

The radiant heat from the flames is what kills quickest, which is why I despair when I see people in short sleeves, shorts and no head gear; long sleeves, long trousers (both of cotton drill) and a broad-brimmed hat are the minimum and I keep a couple of old reusable cotton nappies (OK, "Diapers"; the Oz ones are about 2' square) to dampen and tie over my face if I'm really confronted.

And remember that smoke ionises the atmosphere, making radio transmissions (even mobile phones) a bit dodgy.

Cheers, Rowan

Subject: BS: fires near Auburn, CA, destroy homes
From: open mike
Date: 31 Aug 09 - 04:11 AM

I hope you are safe, Joe, i think this might be near you.

Subject: RE: BS: fires near Auburn, CA, destroy homes
From: open mike
Date: 31 Aug 09 - 04:30 AM

http://www.digitaljournal.com/article/278526

To the north, at least 60 structures — many of them homes — were destroyed in a fast-moving fire that broke out Sunday afternoon in the Sierra foothills town of Auburn northeast of Sacramento and the governor declared a state of emergency in the area.

The fire had consumed 275 acres amid high winds and was 50 percent contained Sunday night, CalFire spokesman Daniel Berlant.

Berlant said it was not clear how many of the burned structures were homes and it was likely to remain uncertain until daylight.

Read more: http://www.sfgate.com/cgi-bin/article.cgi?f=/n/a/2009/08/29/national/a152510D83.DTL#ixzz0PkLEmPgh


http://www.kolotv.com/home/headlines/56257017.html

Subject: RE: BS: fires near Auburn, CA, destroy homes
From: Joe Offer
Date: 31 Aug 09 - 05:43 AM

The fire is about ten miles from me, in a semi-urban area. It was a fairly clear day, so the fire was quite spectacular to see. It was a realtively small area, about 275 acres - but some 30 homes were lost. I haven't heard if any friends have lost homes, but my best friends in the area were spared.

-Joe-

[threads combined]

Subject: RE: BS: Building in Fire-prone areas
From: John on the Sunset Coast
Date: 31 Aug 09 - 11:27 AM

I think were fairly OK except for air quality. They're setting a backfire as I write just over the ridge about 3/4 mile away. No wind, so I expect it to work.

Canadian air tankers are expected to be making dropsa very shortly. Thank you all. And thank everyone for their good wishes.

I am asthmatic, but so far no problem, but I think I'll try to get a prophylactic steriod injection, and beat it the hell out of Dodge for a couple of day.

To Joe, and all the rest of you folks in fire areas wherever you are, my prayers are with you, too.

Subject: RE: BS: Building in Fire-prone areas
From: GUEST,Joe Offer at the Women's Center
Date: 31 Aug 09 - 07:53 PM

Well, I'm kind of numb. I found out today that two good friends lost their homes.

My friend Dave lost his 19-year-old son in June. The young man got out of the swimming pool and collapsed and died of an enlarged heart. Dave and his wife were hit broadside in July, and their car was totally destroyed. And yesterday, he lost his house.

Barbara is another wonderful woman, who spends a lot of time visiting people in retirement homes in the community. She organizes us to sing at a number of retirement homes every Christmas and Fourth of July. She has a gentle, funny, wonderful way of dealing with the aged. And now she's lost her home.

It's so sad. Auburn looked normal this morning, but the road to Dave and Barbara's homes was blocked off. These photos show what's left of where they lived.

-Joe-

Subject: RE: BS: Building in Fire-prone areas
From: Alice
Date: 31 Aug 09 - 07:59 PM

Oh, that's sad.

Subject: RE: BS: Building in Fire-prone areas
From: pdq
Date: 31 Aug 09 - 09:35 PM

Last report I heard was that over 50 homes in the Auburn area burned down.

This is a small town by most standards.

Let's hope there will be no more destruction.

Subject: RE: BS: Building in Fire-prone areas
From: Sandra in Sydney
Date: 31 Aug 09 - 09:49 PM

thanks for the link to the photos, Joe & I'm sorry to hear about your friends losses

sandra

Subject: RE: BS:Building in Fire prone areas - 2009 fire season
From: GUEST,Jim Martin
Date: 01 Sep 09 - 06:33 AM

Is it my imagination or are we getting more and bigger fires each year (global warming)?

Subject: RE: BS:Building in Fire prone areas - 2009 fire season
From: EBarnacle
Date: 01 Sep 09 - 02:26 PM

I believe that the problem is largely development in areas which are not designed to support housing.

A related problem is people often build their homes on the beach or in a flood plain. The land gets eroded or flooded. The houses are destroyed. Then the people come back and rebuild in the same place because it's theirs.

Much of Southern California is a low rainfall zone. The growth there is subject to regular fires, which, when allowed to occur unchecked, clear the area and allow new growth. The fact of human development forces the need to fight these fires to protect the property which should not be there. It also keeps the fuel from being destroyed periodically, amking the fires worse than they might have been.

Will the people rebuild in the same place? Probably. Will the houses and buildings be more fire resistant? I hope so but I don't know.

There are real public policy issues here that need to be discussed.

By the way, Joe, I really do have sympathy for those who lost all they had, such as your friends. I hope they can rebuild somewhere else.

Subject: RE: BS:Building in Fire prone areas - 2009 fire se
From: Rowan
Date: 01 Sep 09 - 06:46 PM

Joe, have a supportive hug from me and pass it on to your friends.

Cheers, Rowan

Subject: RE: BS:Building in Fire prone areas - 2009 fire se
From: Sandra in Sydney
Date: 01 Sep 09 - 07:27 PM

speaking about folks rebuilding in unsuitable places.

In 1987 I was visiting friends in Adelaide (capital of South Australia) who took me touring around, including to the hills area, site of huge fires in recent years and pointed out various sites of interest, including homes destroyed in the fires. Most folks ere rebuilding in the exact same space in formerly tree-filled blocks, which would again be filled with plants & trees over the coming years.

They had spoken to one homeowner sometime before the fire season, who had said with his swimming pool & pump he'd be safe in any fire. We looked at his burnt out site where he had died in the fire.

sandra

Subject: RE: BS:Building in Fire prone areas - 2009 fire season
From: Joe Offer
Date: 01 Sep 09 - 11:52 PM

The strange thing, EBarnacle, is that the fire happened in an area that you wouldn't think would burn. Now, I'm in an old farmhouse in the kind of area that is very vulnerable. We have what they call a "defensible space" cleared around the house, but there's still enough vegetation that I really doubt that we're safe. And if we cleared it all, our comfortable house would heat up like an oven.

Near my friend's home, there was a gully that apparently amplified the wind and funneled the fire up into the housing tract. I saw the fire site today. It burned grass around buildings for a long distance and did very little damage, and then funneled into that one housing tract and brought total devastation. I didn't get into the housing tract, so I didn't get to see the worst of the damage.

My friend Judy, who's from the Auburn area, called this evening and sounded very serious. She had heard that we had lost our home, and she was relieved to hear we were far away from the fire. I've had several calls from friends who wondered if we were affected, but Judy was the first who actually thought we had been hit. I said above that's an interesting phenomenon about living in a rural area - you may know people really well and see them several times a week, but not even know exactly where they live.

-Joe-

Subject: RE: BS:Building in Fire prone areas - 2009 fire season
From: JennieG
Date: 02 Sep 09 - 12:06 AM

I think I read somewhere once that fires follow the same path they have taken before. A friend told me of someone she know whose home was built on a ridge in a heavily treed area, which one day was consumed in a bushfire. They rebuilt in the same place, and several years later the same thing happened. I think they have rebuilt again but know it will probably be a matter of time until their home goes up in flames. Apparently on each occasion the fire has followed exactly the same route.

Nature in her fury....there's nothing like it.

Cheers
JennieG

Subject: RE: BS:Building in Fire prone areas - 2009 fire season
From: EBarnacle
Date: 02 Sep 09 - 10:26 AM

I'm glad you weren't hit, Joe. As you say, though, the general case does apply.

Richard Henry Dana mentioned, in 2 years before the mast, that some of the earliest Spanish colonies in California failed due to arid conditions.

Subject: RE: BS:Building in Fire prone areas - 2009 fire season
From: John on the Sunset Coast
Date: 02 Sep 09 - 11:54 AM

The fire is now safely away (if such can be) from our home. In fact, most of the inhabited areas near us are out of danger. The fire is still raging, but moving away from us. We hope that it ceases to a problem quickly.

Being the mild-mannered, unopinionated person you know me to be, I had words with several lookie-loos who came up to the barricades, or stood in my driveway, binocular or cameras in hand to get a sick thrill. Mostly all they saw was a bunch of thick smoke, and helicopters which looked as if they had umbilical cords attached to their belly for the retardant drops. Some imbiciles came from 25 or so miles away for this experience. Often, they impeded the progress of emergency vehicles; at least one was ticketed that I know of.

I have not heard of any civilian deaths in connection with the various SoCal fires, but at least two brave firefighters were victims of the inferno.

My heart goes out to everybody who has lost, or has had damage to their homes, here and everywhere. Joe, I hope your friends are made as whole as can be, and really soon.

JotSC

Subject: RE: BS:Building in Fire prone areas - 2009 fire se
From: Rowan
Date: 02 Sep 09 - 09:26 PM

Near my friend's home, there was a gully that apparently amplified the wind and funneled the fire up into the housing tract.

Fire behaviour "usually" follows predictable rules. In wooded vegetation of the sort on SE Oz (not dissimilar to California, I'm told) it's the preheating effect of radiated heat that can be most influential. On a windless day in a perfectly flat area, radiation is probably the same around the whole periphery of a fire. Any wind will cause the flames to lean downwind, increasing the radiant heat load of any fuel downwind. This means the main flame front will "run before the wind" in perfectly flat terrain. In Oz vegetation, the rule of thumb in windless conditions is that the speed of flame front movement will double for every 10 degrees of slope, as the fuel upslope is preheated more rapidly as the angle between the flames and the ground decreases. A narrow gully intensifies this as the bottom of the gully will usually have a decent slope to it and its sides will restrict the radiant heat to the immediately adjacent fuel even in windless conditions, Any wind will usually funnel up the gully, intensifying the whole effect.

If this wasn't bad enough, a fire racing upslope can occasionally create a sudden vortex that is horizontal and fully flame laden for up to 100m (300') across the slope at right angles to its main path. As far as I know, there has (yet) been no way that this behaviour can be predicted. Not a good place to be caught out in the open.

The very worst place to build a house is at the head of gully that faces the prevailing winds during a fire season, but it's often the location that gives the best views.

Sigh!

The fuel most vulnerable to becoming preheated by radiation in bushfires is vegetation with a diameter less than 6mm or 1/4"; grass, twigs, bark all carry very fast-moving fires. Some species may be fire retardant because of their chemical makeup but others accelarate flame rates for the same reason. Minimising the quantity and arrangement of fine fuels downslope and/or upwind of one's house for a minimum of 30 metres (100') is a necessary (but sometimes insufficient) precaution; fires that are crowning (moving through the tree tops in front of flames at ground level) will have a high radiation output at least four times further away ("horizontally)") than the trees' height, increasing the clearance distance even further.

All the best!

Cheers, Rowan

Subject: RE: BS:Building in Fire prone areas - 2009 fire season
From: EBarnacle
Date: 06 Sep 09 - 07:11 PM

For those who are near a TV, 60 minutes is devoting a major segment to this story tonight.