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Fire tactics (ventilation blower)
In Poland there are certain law regulations that determinate what you can and cannot do during a rescue action.
Course no one really cares about them when it comes to a real situation the point is to rescue lives. And as far as everybody is all right there’s no problem at all, but it starts to get messy when someone gets hurt. Then they start to analyze the procedure of the action, and if something isn’t write it’s all on the head of the commanding the action.
There are norms like this that say that a ventilation blower (e.g. tempest) shouldn’t be used then there’s an open fire (e.g. in a burning building when firefighters go inside), to eliminate the risk of a back draft .
I’ve seen some actions done in US and I realize that You guys use ventilation blowers when entering a flaming building which is a great idea when there’s no lack of oxygen in the burning area. The flames aren’t bursting in your face but the other way if the blower is behind you, the smoke is getting the hell out of the area so there’s a better visibility, you even get to chill the burning zone, and the hot combustible gasses. BUT HOW CAN YOU TELL either there’s a lack of oxygen that when ventilated causes a back draft or there’s isn’t one ? Pleas I would really like to know cause I’m now on a training to become a unit commander (I don’t know the significant function/status in US) so it would like to discuss this matter with my lecturers, comparing your experience, and of course use this knowledge in action.
Thanks a lot. Stay safe.
Course no one really cares about them when it comes to a real situation the point is to rescue lives. And as far as everybody is all right there’s no problem at all, but it starts to get messy when someone gets hurt. Then they start to analyze the procedure of the action, and if something isn’t write it’s all on the head of the commanding the action.
There are norms like this that say that a ventilation blower (e.g. tempest) shouldn’t be used then there’s an open fire (e.g. in a burning building when firefighters go inside), to eliminate the risk of a back draft .
I’ve seen some actions done in US and I realize that You guys use ventilation blowers when entering a flaming building which is a great idea when there’s no lack of oxygen in the burning area. The flames aren’t bursting in your face but the other way if the blower is behind you, the smoke is getting the hell out of the area so there’s a better visibility, you even get to chill the burning zone, and the hot combustible gasses. BUT HOW CAN YOU TELL either there’s a lack of oxygen that when ventilated causes a back draft or there’s isn’t one ? Pleas I would really like to know cause I’m now on a training to become a unit commander (I don’t know the significant function/status in US) so it would like to discuss this matter with my lecturers, comparing your experience, and of course use this knowledge in action.
Thanks a lot. Stay safe.
Replies to This Discussion
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Permalink Reply by Tony P on
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Positive Pressure for attack is a recognised method, but I don't think it's that common. Definitely not common in my part of the world! We only use the fan for ventilation.
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Permalink Reply by Chris on
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we differ to the US in that we do not under any circumstance ventilate a fire. We make entry, extinguish the fire and once it is blacked out put a PPV to work to clear the smoke. When a crew makes entry, no FF will break windows etc for fear of fueling an O2 deprived fire. If the house is fully involved it has usually self ventilated, or is about to. In that case we would not be doing internal fire attack or a primary search and rescue, but defensive from outside and protecting neighboring property. As far as oxygen deprived fires go we are trained to "read" the smoke colour and behaviour. Is it "pulsing" and "pushing " from vents and windows? On entry we open the door, 2 quick gas cool pulses, have a look then shut it. Did the smoke pulse out? Was it thick black or brown? This is an extremley involved topic. Have a look at vids marked "backdraught", watch the FF's standing in front of the opening pouring water in, with that thick dirty brown smoke "pulsing" out and being sucked back in. Its so obvious that the place is about to blow, Thats when the door should be closed. Stick a PPV to that, and the result would be impressive to say the very least :) Also if a PPV is used you may end up taking the fire from a 5 bed house with 1 room involved to a 5 bed house with 5 rooms involved as the flames are pushed through the building by your PPV. My 2 cents from the other side of the world, stay safe mate.
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Permalink Reply by Ben Waller on
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Making this determination about when to use ventilation blowers (PPV fans) is fairly simple with a few basic assessment tools and some practice in controlled training situations.
1) The fire location must be known.
2) The fire location must be adjacent to an exhaust opening (window, door, roof scuttle, etc.)
3) An intake point must be available on the upwind side of the structure if there is substantial wind.
You can usually rule out the potential for backdraft by reading the smoke and fire. If flames are ventilating from the exterior, the fire is very unlikely to backdraft. If there are open windows or doors with smoke venting from them, backdraft is unlikely.
Backdraft is most likely in unoccupied buildings that are tightly sealed up and that have had a delayed alarm that gives the fire a head start. Pre-backdraft smoke is usually leaking out of small openings like cracks in the walls, since there are no large openings to vent the fire. Windows will have a dark, baked black color, usually fairly uniform from top to bottom. Pre-backdraft buildings can seem to "breathe" - in other words, there may be small puffs of smoke that seem to puff out of small openings, then get sucked back inside. This is due to the fire trying to get enough air to become free-burning.
Potential backdraft conditions can be alleviated by vertical ventilation at the structure's highest point.
Once the pre-backdraft condition is converted to a free-burning state, you can make horizontal openings to fight the fire at that point. If a true pre-backdraft situation is present, there is zero chance of a rescue in the fire area, so defensive (exterior attacke), not PPV are generally indicated, particularly in single-family dwellings.
The "Reading Smoke" class offers some tips on recognizing pre-backdraft and pre-flashover conditions. Here's a link: http://www.firefighternation.com/forum/attachment/download?id=88975... from another FFN discussion.
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Permalink Reply by Art "ChiefReason" Goodrich on
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If you are interested in learning more about PPV/PPA, I would contact either of two people:
John Kriska or Paul Grimwood. You can see alot at www.firetactics.com.
Using fans either offensively or defensively can be tricky, especially in high wind conditions.
And if you haven't got someone who can watch and assess changing conditions, then the fan will just quicken the burn rate.
TCSS.
Art
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Permalink Reply by John Kriska on
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To support Ben's explanation on a backdraft, here is a video depicting a backdraft. Krystian, rather than me repeating myself on the use of PPV as an attack tool (PPA), I refer you to this site's forum section. Search for "positive pressure ventilation" or "positive pressure attack." There have been some great discussions on this topic and I think you may learn from these posts. As an instructor of PPV and PPA, If you have any questions please contact me at fckrisk@yahoo.com and I would be happy to assist you in understanding the concept.
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bkdraft1.wmv, 1.2 MB
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