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Advances in Fire and Rescue Technology?
He Definitely Didn't Inhale asks: "As anyone could imagine, being trapped inside a burning building would be terrible, but people risk their lives every day to save people stuck in that situation. While fire sprinklers are installed in some buildings they are far from ubiquitous, and also tend to cause plenty of water damage during their use. Some server rooms are isolated and can be filled with an inert gas in the case of a fire, but people - and fire - need oxygen to live. Another idea has recently been patented (USP#6,446,731), whereby a truck mounted high capacity fan is used to remove smoke and heat from burning buildings through the use of an extensible tube. This could make it much easier and safer for firefighters to rescue building occupants and put out the fire. Are any similar technologies or methodologies in use today? What are some design issues that may need to be resolved before this concept can be used safely and effectively? Are there any reasons not to pursue the development of this potentially life-saving idea?" Earlier this year, Ask Slashdot discussed Halon systems. Folks interested in this topic may want to give that previous article a read.
Yes, it will fan the flames, but flame isn't what kills people. It's the heat and especially the smoke. By the time fires reach people, they are already dead.
For a while now they've had gas engine powered fans. They open the front door, open a hole on the roof, and point the thing straight into the house. The cool air blowing in displaces the heat and smoke so the firefighters can enter and see what they are doing. Usually, the hoses are right behind them, so the fact that the hoses and people can get right into the house with the water offsets any flame fanning effects.
If tits were wings it'd be flying around.
Where have you seen this technique used? This will basically turn the house into a giant blow-torch.
That technique (Positive Pressure Ventilation) is widely used in the fire service, pretty much everywhere in the U.S. It is, as near as I can tell, pretty much ubiquitous. The training materials provided by IFSTA teach PPV, and PPV training materials and equipment are very much in demand in the fire service.
Your point about turning the home into a giant blow-torch does have some validity of course. PPV, when done wrong, CAN have negative consequences. Timing is crucial to do proper PPV. As one of the parent threads pointed out, the idea is to force the smoke and super-heated gases away, clearing a path for the fire crews to advance on the seat of the fire and extinquish it.
Another factor is where the PPV fans are placed. Firefighters are taught to always (when possible) attack a fire from the un-burnt side. What this means, is that when you "push" the fire, whether with PPV fans, or with the air pushing effect of hose-lines with fog nozzles, you push the fire back into territory it's already burned... this is part of the "locate, confine, extinguish" strategy.
If you did the opposite, attacking the fire from the already burned side, you would not want to try and use PPV, or you would indeed be helping to spread the fire into areas that were not yet damaged.
For anybody who's interested, here's a link to some more info: http://www.tempest-edge.com/ppv/
In my experience these fans are usually used to remove smoke from the house after the fire has been extinguished.
That's also a valid use of ventilation fans, although the fans used for negative / exhaust ventilation are usually smaller, electric fans, with less capacity in CFM.
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This building's safety system knows what floor an event has occured on. As soon as an alarm is triggered, the floor above and below the event floor start pumping in extra air to pressurize those areas. While the exaust flume on the event floor(s) start sucking air out of the event zone. The exaust creates a vacume this aiding in removal smoke/heat and also helping to prevent any heat, fire, or gas from escaping the area (as the areas around it have a higher pressure.
Pretty smart little building.
Oh yeah, I should probably also say that while PPV is a valid technique, and what I think one of the parent posts was referring to, it's NOT what the patent is referring to, as best as I can tell. The patent seems to clearly state that the idea is to suck the fire and gases OUT using a vacuum, which is the exact opposite of PPV.
My considered opinion is that the "inventor" of this particular device doesn't know much about firefighting, if he seriously intends to try to fight fire this way. Doing it this way, would most likely just make matters worse, as several people have pointed out.
Of course, he could turn it around, and he'd just have a truck-mounted PPV fan.
Then again, ventilation fans already exist for doing both positive and negative pressure ventilation, and I question whether simply truck-mounting it either way, is sufficiently different enough from existing practice to justify granting a patent anyway.
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Hee..actually this is in response to the venting truck only. I prolly should have explained that.
Sprinkler Systems ROCK. Haylon (newer chemicals) systems rock. Just don't be stupid when the alarm goes off...you should have plenty time to evacuate or cancel the countdown before the system purges.
Don't even think about fighitng a winning battle with a fire using the hoses provided to you in a building (or a garden hose for that matter). Hoses in a house or building should ONLY be used in a situation where your only means of egress is through a fire (preferably small).
Actually, firefighting techniques can be pretty geeky. New techniques and equipment are being developed by firefighters on a regular basis. Almost all tools were designed by firefighters in response to needs that can't be fulfilled by the tools provided at the time.
If you are interested in learning more, consider volunteering with a fire company. Personal equipment and training are usually free. Some companies provide housing for free to students in exchange for students providing time and service to the company on a daily basis.
The rewards are great! You will be healthier for it, you will meet plenty of life-long friends, and you can't describe the feeling of saving somebody's property and most importantly somebody's life.
My big question is, how do you deal with structural failure in the burning section?
That's a HUGE question facing the fire service, whether you use PPV or not. There are really three basic techniques to handle that issue.
1. size-up, and make a determination if an aggressive interior attack is feasible in the first place. If there are signs of imminent structural collapse, go defensive mode, "surround and drown."
2. If you initiate an interior attack, allow a certain amount of time (varies from dept. to dept, but for example, let's say 10 minutes) from the time interior attack is commenced... if the fire isn't contained in that amount of time, pull-out, and switch to defensive mode.
3. teach firefighters and officers to recognize certain signs of impending collapse. This is why one of the courses required for FF certification is something called "Building Construction." Firefighters are taught in a fair amount of detail how buildings are put together, and how the stress of a fire works against the building's construction. This helps them to recognize warning signs. It's also part of the size-up process I mentioned in 1 above. Recognizing balloon-frame construction as opposed to heavy timber construction for example, is a factor in determining the likelihood of a collapse. Another example would be recognizing the presence of pre-fabricated trusses, which are considered by many in the fire service to be one of the greatest dangers around.
Oh, and pre-planning also comes into play. Can't forget that. Fire Departments usually visit most commercial buildings in their districts on some regular basis (annual, for example) and one of the things they may note down for reference, are details about the building construction (plus things like where the fire department connection for the sprinkler system is, the closest fire hydrant, etc.)
It would seem pushing fresh air into a burning section would help consume more fuel (i.e. the wood holding the second floor from falling on your head).
Yes, there is something to that. PPV is not a magic bullet. It's use has to be taught, and firefighters and officers have to understand where , when and how to use it, and the ramifications of doing so. Used properly it can be a HUGE help in handling a structural fire. Used improperly, it can definitely help burn a house to the ground real fast. In fact, I would not be surprised if a fire department one day gets sued for negligence for misusing PPV and burning a house down. And for what it's worth, yes I have worked fires where PPV was mis-used and caused more harm than good. I think that usually happens in fire departments where they get their first PPV fan, are all gung-ho to use it, and haven't had the appropriate training yet to really understand it.
For anybody who's interested, here's a good article that talks about PPV in some detail:
http://www.firetactics.com/PPV-GRIMWOOD.htm
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Actually, it's interesting that no one has mentioned wildland firefighting in this discussion yet. Although I think you're right that the basic techniques of combatting wildfires hasn't changed very much--and probably won't in the foreseeable future--I think there have been tremendous technological changes in determining when and where wildfires are fought.
The most obvious change has been lightning detectors. There are very few fire lookouts staffed these days; automated detection systems plot where strikes hit, and planes can check out almost immediately if they have started a fire or not. Ground-based systems are still prevalent but there are now orbital imaging systems coming into play to do the same thing, with even greater accuracy.
Every leap in weather forecasting has helped wildland firefighters. Knowing when the wind and humidity are going to be on your side is a critical factor for deciding when to take on the fire and when to stay back. Being able to assess these factors in the field with smaller and better detection equipment has changed the nature of the game.
Helicopters, parachutes, air-drops... these are all fairly recent innovations that have dramatically expanded options for firebosses.
Then there are the more pedestrian advances, such as GPS and lightweight mountain gear, which benefit any backcountry traveler, but of course also make life easier for people who are not only having to fight a monstrous wildfire, but having to hike some of the most rugged terrain in the world to do so.
I'd say there have been more changes from technology in wildland firefighting in the last hundred years than there have been in structural firefighting--they're just not as obvious.
No relation to Happy Monkey