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Hardware Science Technology

Advances in Fire and Rescue Technology? 50

Posted by Cliff from the your-friendly-neighborhood-fireman dept.
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.
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Advances in Fire and Rescue Technology? More

Advances in Fire and Rescue Technology?

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  • 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.

    Now I haven't read the patent, but wouldn't such a system cause a negative pressure situation in the building, causing it to pull in more fresh air, thus fanning the flames?

    Maybe I'll go read the patent and
    • Two words:

      "FIRE PASTE!"

    • Re:fanning the flames... (Score:4, Interesting)

      by PD ( 9577 ) * <slashdotlinux@pdrap.org> on Thursday October 16, 2003 @03:31PM (#7232511) Homepage Journal
      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.
      • They open the front door, open a hole on the roof, and point the thing straight into the house.

        Where have you seen this technique used? This will basically turn the house into a giant blow-torch. In my experience these fans are usually used to remove smoke from the house after the fire has been extinguished.

        • Re:fanning the flames... (Score:4, Informative)

          by psykocrime ( 61037 ) <mindcrime@cpph[ ]er.co.uk ['ack' in gap]> on Thursday October 16, 2003 @04:26PM (#7233256) Homepage Journal
          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/ [tempest-edge.com]

          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.
          • Oh, yeah, since this is Slashdot, I should probably point out that yes, IAAFFI (I Am A FireFighting Instructor), who has been certified to teach IFSAC accredited Firefighter I & II training courses, by the state of North Carolina.
            • I'm going to have to do some reading on this. My big question is, how do you deal with structural failure in the burning section? 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). Or does this have limited use in larger structures?

              • 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. t

          • Re:fanning the flames... (Score:4, Insightful)

            by psykocrime ( 61037 ) <mindcrime@cpph[ ]er.co.uk ['ack' in gap]> on Thursday October 16, 2003 @04:40PM (#7233415) Homepage Journal
            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.
          • You sound just like my Fire Fighting Instructor. Hmm wonder why that is? Oh, you know what your talking about!
          • Plus, as far as I remember, you don't usually vent until you have a supplied line in position to attack with. To attack without venting the structure is begging for a flashover; it's a technique that's been in use for years and years. PPV is a pretty neat trick to amplify the effect, though.
            • I'm on a volunteer rural fire department, and we've had some chances to fill a vacant house with smoke and practice venting it. It's really amazing how fast one of those fans can clear out a house.
        • I've seen it on a TV show (a documentary, not a drama) and Fire Rescue magazine talks about it too. http://www.jems.com/firerescue/e0302c.html is the link, and it specifically talks about the flames being blown towards the vent that was created.

          I think I explained why the house would NOT be turned into a giant blow-torch by a fan that can force cool air into a single room. You're not going to be blowing hurricane force winds into every room at the same time.

    • Saw a bit on something like this on PBS a few years back (8-10 years).

      They profiled a rural volunteer fire department that was useing a hot air ballon inflation fan. They would place it in an exterior doorway and pump outside air into the structure. This allowed the firefighers to wear lighter turnout gear, move faster, and see the fire easier (no smoke filled rooms).

    • I was thinking the same thing. Afterall, that's the concept behind chimny fires and what makes them so dangrous: the smoke rises and sucks in new oxygen from below. It ends up working almost like a jet engine. There's either something special about said fan or it's a dumb idea.
      • That's what I don't understand about using fireplaces in the winter for heat. Don't they encourage cold air to sneak in through the cracks of the house?
        • Fireplaces are good for localized heat, particularly if you use a duct and fan to move the heated air to a part of the house away from the fireplace. They're also good for radiative heating, which isn't affected by air movement.
      • There's nothing special about the fan. The key to successful use of positive pressure ventilation is in firefighting tactics.

        The fan is not started until firefighters are ready to immediately enter and attack the fire. In some cases the fan can create a bit of a chimney effect, but the benefit of the immediate improvement in interior conditions is so great that the fire can be knocked down much more quickly than without.

        Bear in mind, also, that putting out the fire is only one of the firefighters' goals.
    • The same reason you can blow out a candle...

      Fire requires three things, temperature, oxygen and material that can burn. Take away any one of those, and there can be no fire. When you blow cool air at a sufficiently high rate at a fire, the flames die down, creating a path for the firemen to enter and engage the fire.

      Anyone whose ever tried kickstarting a campfire by waving something planar as fast as possible know how this works.

  • It seems to me that just sucking the air out of a burning building, without carefully figuring out where the fresh air is going to enter, is likely to make the fire more intense.

    It might make more sense if it was an equalized system, where the amount of air being sucked out, was replaced with an equal amount of fresh air being blown in. You could also atomize water into the blown air to help increase the humidity in the room.

    I don't see this system working well for a whole building, but seems like it coul
  • Am I the only one that thinks sucking out post-combustion gasses (which will ge replaced by nice fresh air full of oxygen) is a terrible idea?
    • No, I bet you are far from the only one, but post-combustion gases must be exhausted from the building to prevent explosion. Superheated air and sprinkler water combine to form lots and lots of superheated steam. Although fresh air rushes in and helps the fire burn, it also pulls the fringes of the flame away from uncombusted areas. The same thing that happens when the wind shifts the right way in the event of a forest fire.

      Like when a business cuts losses, sure it doesn't cut the losses that have already
  • I've just cut my hand off with a power tool so I'm typing this with one hand. I'm not sure if I should call the hospital or if they have an email address or web form that I can use to submit a request for an ambulance. Does anyone know?

    (Some things just don't seem appropriate for Ask Slashdot, ya know?)
  • Please go do your own research, Joe Sorosky. If you're going to make a corporate pitch, it'd be better for you to have factual references other than "Well, these guys on Slashdot said ..."

    Let's see, 'IANAL' won't work here. How about 'IANYPRB' (I Am Not Your Personal Research B*tch) ?

  • The building I work in (Score:3)

    by tenman ( 247215 ) <<moc.iausten> <ta> <gro.todhsals>> on Thursday October 16, 2003 @04:38PM (#7233389) Journal
    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.
  • Just for some reference, I am a volunteer firefighter in my spare time.

    First we need quick lessons in one of many effective venting techniques called Positive Pressure Ventilation (PPV) [unifire.com].

    Here is an example of a PPV fan [mac.com].

    The vehicle-mounted fan basically works in the opposite direction. We actually have an electric fan that was used in a similar fashion (Smoke Ejector). "Used" being emphasized. It has been proven over and over again in training and actual fire events that "sucking" air out of a building
    • 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 whe
  • Speaking as a fire fighter, I can say this, sprinklers are usally cut off almost immediately upon arrival. The reason is this, the water supply is limited as it is, and the stand piper are intdended to be filled by the arriving pumper/tanker trucks.

    Additionally, I like the idea of having sealed rooms. I have seen some concrete enclosure that are great for keeping the room cool in general, although sometimes a moisture buildup is the side effect, but is also good for keeping heat out. As an aside, firef
  • A few more things that represent improvements.
    • Barricade Gel [barricadegel.com], which you can spray on something and it becomes highly fire resistant;
    • Thermal Imagers [cairnsat.com] can spot victims through smoke and fire or hotspots through walls;
    • The e911 system involving GIS mapping.

    But despite cool stuff, it seems most firefighting is not technological and has only evolved slowly over the last 100 years. Wildland firefighters still use a shovel and not much else, even with air drops. Someone must still risk life entering a b

    • Re:other advances (Score:3, Interesting)

      by ScuzzMonkey ( 208981 )
      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 stri

  • It's the same reason that blowing on a fire reignites coals, and they have those blowing devices for fireplaces (yeah, I'm sorry, the name escapes me at the moment). As long as there is any oxygen content, moving air will just provide a fresher fuel and inflame the fires.

    Obligatory, karma-whoring quote "Inflammable means flammable? What a country!"

    • I know that we used to use some old bellows for stoking the fire at home. [A little hand held version, as opposed to the giant ones that you'd find in a blacksmith's shop]

      But yes, air makes fire hotter. That's why you close the vents to slow cook on a charcoal grill, and why they force air into blast furnaces for smelting.

      Although part of the issue is oxygen being fed in, it also helps to blow off the layer of ash that forms over the coals, allowing them to get enough oxygen for them to burn, and to kee
  • We have a co-location where they use FM 200 [firefire.com] and you can Google for FM 200 [google.com]. It does not displace oxygen, thereby not inducing the risk of suffocation. It's very expensive, but compared to the loss of life price shouldn't matter and could be cheap at thrice the price.
  • I live in a small Texas town with a volunteer fire department. Our fire department has has a truck with a fan for about 10 years now. Admittedly, it doesnt have the ducting but is effective none the less. This is not a new concept.
  • Maybe you should look here [e-one.com] and here [firetimes.com] bfore you get dollar signs in your eyes. That is unless you own the patent and want to pull a SCO in the fire fighting industry.
  • Slightly Off-Topic but a couple of hours ago was wondering this, then noticed this article.

    Could someone explain the differences in 1, 2, 3, 4, 5-alarm fires?

    I've heard it was the number of stations that are asked to respond to the fire, but dont know how accurate that is.

    I searched google for things like, fire alarms fire alarm codes, fire codes, three alarm, five alram, but all i get or advetisers for cheap fire alarms and news stories about varying alarmed fires in the news.
    • Totally Off-Topic
      The one-l lama,

      He's a priest.
      The two-l llama,
      He's a beast.
      And I will bet
      A silk pajama
      There isn't any
      Three-l lllama.

      The author's attention has been drawn to the kind of conflagration know aas a 'three-alarmer.' Pooh.
      (Which, I hope, you recognize as being by Ogden Nash.)
    • I could be completely wrong here but I think it simply means how many stations were called for the fire (had their alarm go off).

      a 1-alarm fire would be the nearest station had to come out and control it, a 5-alarm would be a fire that took the 5 nearest stations to control it.

    • Sorry about the really late reply. The alarm system is used to preplan unit assignments for response. A quick google search for "box alarm" will get you some relevant links. The system is in place to make the best use of limited resources, as you wouldn't want the entire borough of Manhattan to respond to a car fire in front of city hall. It's used more for individual units than entire stations, as that would not be very resourceful.
  • There is a company that uses the water itself to cut through a wall, which means that the fire is defeated as soon as you get inside without any unnecessary oxygen addition.

    Since you only need one tool to get inside, rescue and extinguish this can save a lot of time and maybe lives. There might be cases where it's not the perfect tool so it cannot replace everything else, but for those cases it excels it have had a lot of success.
    • Sorry, link [ccs-cobra.com]...

      There is a company that uses the water itself to cut through a wall, which means that the fire is defeated as soon as you get inside without any unnecessary oxygen addition.

      Since you only need one tool to get inside, rescue and extinguish this can save a lot of time and maybe lives. There might be cases where it's not the perfect tool so it cannot replace everything else, but for those cases it excels it have had a lot of success.

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