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Cheap AC/Fire Safety

Cools your home and provides ventilation during a fire
  [vote for,

This came to me while sweating up a storm trying to sleep. It's the time of year when it's not going to stay hot long enough for the AC, but the days are warm enough to heat up your house. The evenings are nice and cool. So a small modification to your central air system should do the trick. Simply install a valve/baffle that blocks off the cold air return to your furnace and opens to a filtered duct leading directly outside. Turn on the fan and voila nice cool air circulates through your house.

Now the second part. During a fire, fire fighters often put large fans at the door to blow smoke out of the house. I propose the same idea as described in the first paragraph but give your furnace fan a super highspeed setting for when the fire alarm goes off. This would essentially pump thousands of litres of fresh air into the house at floor level enabling better vision to get out of the house and possibly improving the chances of the elderly and invalid who can't move well. If your trapped by the fire just curl up next to the vent. An exhaust vent would be needed at the back of the house as somewhere for the smoke to go. ( a pusher fan on this exhaust could help with smoke extraction)

TBK, Oct 03 2002

PPV Fan tactics http://www.firetactics.com/PPV.htm
How to use/not use PPV fans [oneoffdave, Oct 21 2004]


       I would think that the fans the fire fighters use only pull smoke out - to provide fresh air will only fuel the fire.
yamahito, Oct 03 2002

       I'm afraid my thinking is along the same side as yamahito's. Better to just keep a breathing apparatus near your bed or something like that.   

       On the topic of that, why don't we see such things as readily available as fire extinguishers? We always hear how "the people died in the fire due to smoke inhalation". If they had a simple mask with goggles connected to a 5-minute supply oxygen tank (which would be nice and small, not too cumbersome), wouldn't they make it out?
Wes, Oct 03 2002

       Not to be snippy, but what to you think is being blown into the house by those fans? They blow air into the house and usually chop a hole in the roof for an exhaust. If you house gets to the point that your worried about fueling the fire, your house is pretty much screwed anyways. Might as well live to see it rebuilt.
TBK, Oct 03 2002

       Two things: first, the whole-house fan system I have in my house works much as described here in the first section. The fans are located in the upper floor ceilings and duct to the outside to remove air and the makeup air--the air brought in to the house to replace that which the fans remove--is outdoor air routed through the heating duct system and distributed throughout the house. It is, in fact, servo-controlled baffles in the cold air return system that control which air source is routed to the heating system. When the outdoor source is selected (when the fans run) one baffle changes the air source and a second baffle bypasses the furnace, routing the outdoor air directly through the air-filtration system and to the duct network. The fans and the cold air makeup source are controlled together, as one system, with a programmable interval timer mounted on the heating system itself.   

       Our hvac contractor explained that, because modern houses are sealed so tightly these days to comply with energy conservation building codes, these whole-house fans are necessary (and required by code) in order to provide sufficient fresh air for health reasons.   

       Second, while I don't know this for a FACT, I am thinking that the firefighters perform their rescues before ventilating the building. I may be wrong but it doesn't make sense to me that they would force oxygen into a building while people are still in it.
bristolz, Oct 03 2002

       The fans fire-fighters use are called Positive Pressure Ventilation fans and do indeed blow air into the burning building. They can't be used in all circumstances and they require a vent to be made in the opposite side of the burning building. Far more information than one might possibly need is available at the [link]
oneoffdave, May 21 2003


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