Fire survivablitity of tight houses?
I was perusing Treehugger.com and came across one of their April Fools articles. ( http://www.treehugger.com/green-architecture/tall-plastic-future-building-america.html ) In it there is a UL video showing how much faster modern furnishings (made out of frozen gasoline as stated in the youtube about section) reach flash over compared to old style furnishings made out of “natural” materials. This got me thinking about how air tight homes might perform in a fire. I quickly realized that I am in no way qualified to answer that question in even a theoretical manner. So my question basically is have there been any fires (official or otherwise) that might indicate how survivable (human not necessarily structure) a tight home may be?
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Donald,
I have never heard that low rates of air leakage through your building envelope either increase or decrease the time frame for escaping from a building fire. The amount of air needed to encourage the draft of a raging fire is on a different order of magnitude from the volume of air leaking through building cracks.
My gut feeling on the matter is the difference, if there is one, is on the magnitude of a few seconds. It's my understanding that the greatest life threat during a fire is smoke inhalation. A life threatening fire is still going to produce more smoke than can be evacuated by even a very leaky house.
I guess my main concern is that sealing up a house well may affect how a fire in that house behaves, thus changing needed evacuation times.
Regardless, I don't think it changes (what I feel is) the best practice of installing a well designed residential sprinkler system. That may be all that really matters anyway.
Smoke will kill you long before the fire does. The more smoke alarms the better. Detect sooner and get out.
Sprinklers are great idea but I cant say how well they stop the smoke in the early stages of a fire from reaching dangerous levels, Sprinklers do require a fair amount of heat before tripping.
Scottsdale made sprinklers mandatory in the late 90s for residential buildings. It was part of their fire department staffing process. I think some other areas have the same requirement.
Donald, Sprinklers are a good way to avoid property damage (and cause some too), but their value in saving lives in house fires isn't that great. The increase between the chance of surviving a structure fire when living in a house with working smoke detectors to one with sprinklers is only .44%.
Malcolm in my field (healthcare) .44% is a significant finding. That said do you happen to know the difference (if there is one) in smoke inhalation injuries, in house fires in homes with working smoke detectors vs. homes that also have sprinkler systems?
No sorry I don't. Maybe I should flesh out that statistic to give you an idea whether the .44 is worth it. You have a 99.45% chance of surviving a structure fire in a house equipped with a working smoke alarm. Installing a sprinkler system rises that to 99.98%. The increase in cost between the two approaches is nearly 100 fold.
Malcolm: If your numbers are right and I understand your statistics correctly, in 10,000 structure fires, we can expect 55 deaths in houses wth working detectors, and 2 deaths in sprinklered houses. At $5000 to sprinkler a new house, spending $50 million saves 53 lives, or about $1 million each.
I'm early in the design process for a new house. I'll spend the money on sprinklers and skip the Sub-Zero fridge.
Stephen, I hope I'm not dissuading anyone from putting in sprinklers but it isn't a straight forward decision. The overwhelming majority of fires occur in older structures - precisely those that aren't and won't be sprinklered. In comparison, new code compliant houses are remarkably safe.
Once you have removed the risks inherent to older buildings, the largest factor left is occupant behaviour. Smoking, candles, using faulty electrical appliances, cooking fires etc.
So really it seems to me that there are two distinct decisions around sprinkler use. Do they help save lives in general? And will they save my life in my new home knowing how I live?
There are several downsides to sprinklers. As this winter has shown they are prone to freezing, especially during power failures and can cause flooding. The cost is also usually well over that you mention. I received a quote for almost the same amount which was just for the design of a system for a large house.