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Thread: PPV--Again!

  1. #1
    phyrngn
    Firehouse.com Guest

    Post PPV--Again!

    Hello all brother and sister firefighters. As a new forum member, I'd like to wish you all well and pray that you return to your families after every call safe and sound!

    I know that the forum discussed PPV and it's negative effects a while back, however, I was wondering about those of you who actually use it for fire attack. When do you use it, when do you not use it, how do you use it, etc. I have a video from a vendor that has actual fire footage from Salt Lake City...one of the firefighters said that they tried to make PPV fail, and couldn't, and so therefore it is used during fire attack. What are your thought?

    Also, being from a department that uses PPV rather frequently and rarely (if ever) puts anyone on the roof (for residential fires), what are your size up methods for deciding to use Vertical Ventilation? What is your SOP? I know that you want to make the cut as directly above the fire as possible, but how do you decide where the cut point should be and weigh that with your crews' safety? How many people do you put on a roof?

    If any of you have Ventilation SOPs or any Training Resources at all that would help, please e-mail me.

    Stay safe...



  2. #2
    FyredUp
    Firehouse.com Guest

    Post

    We use ppv with fire attack. If the fire is a room and contents fire with no extension to the attic space, and the building can be compartmentalized (any other room doors shut) with removal of the fire room's window the ppv can help reduce smoke spread through out the structure. As well as improve conditions for the attack team, by increasing visibility and temp reductions.

    The biggest negative is people that just don't get it. You can't bust out every window and make ppv work. Unless of course you compartmentalize. Another negative is the noise. All of the gas powered fans are LOUD! Improper use can push fire....but I haven't seen that here at any real incidents, or heard of it from any of our neighbors.

    When to put people on the roof.....that gets stickier every year. With the way buildings are built, trusses, plywood I beams, 7/16 OSB, it just ain't right. Size-up is your guide here. If the fire has any kind of significant hold in the attic void space I just don't think it's worth putting people on the roof. Venting from an aerial is an option. As much as I favor aggressiveness, I more favor taking my entire crew home with me.

    I am sure I will be taken to task for those comments. Remember, I said if the fire has any kind of significant hold on the attic void space.

    With a residential structure the number of FF's would be no more than 3, and usually 2. With complete PPE and SCBA.

  3. #3
    STA2
    Firehouse.com Guest

    Post

    There are two ways to use PPV. There is PPV after the fact which uses the fan and an entry and exit point to remove the smoke and then there is PPV attack. It sounds like you got the PPV after the fact down pretty good from experience. The PPV attack is another animal. I have watched a 3 and 1 house fire go to a 2-11 because the fan was used somewhere between ventilation and attack. PPV attack is great. A scenario if you will. The first Engine Co. of a 3 and 1 arrives to find smoke showing from sector B on side 2 of a one story SFD. The Engine Co. stretches the line to the front door as the officer makes a lap of the house to locate the seat of the fire if possible. He gets to side 2 and believes the fire to be in that area. Next he makes sure there is an exit for the fan which he makes by taking out a window. The Truck Co. arrives and brings the irons and the PPV fan to the front door. As soon as they get water, the door is taken with the fan GOING. The line is stretched to the area believed to be involved. The Truck Co. starts their search as close to the fire area as possible and works their way outward. The fire is located as the search is finished. The fire is knocked down and the Truck Co. starts opening up to check for extension vertically. All said and done. The second Engine Co. laid a supply line and stretched a back-up line. The third Engine Co. was the RIT. Chief 7-1's the box and holds 1 and 1. A very easy scenario I know, but it gives an idea. The key is to have a PPV fan that will push the fire and smoke back while making your stretch and search a little easier.
    When not to use PPV is also a good point. Some considerations if you will.
    1.) Attic fire where you got to open the
    roof or let it open itself.
    2.) Ballon construction. If it is in the
    walls AT ALL you'll push it into the
    attic if its not already there.
    3.) Multiple windows on different
    sides already showing fire. You are
    wasting your time.
    4.) Large open area commercial bldg's. To
    big an area to pressurize with the
    average PPV fan. A half attempt will
    draw it towards you or cause you to
    chase it further than needed.
    5.) MFD fires. Unless you have contractors
    that don't punch thru firewalls, do not
    believe that the fire walls are intact.
    Even if they are, a good Truck Co. will
    start opening up the fire area quick. If
    the fan is running and it got into the
    open area between floors then you just
    gave it a boost and a running chance.
    6.) Any fire that you believe is above you
    and your crew in any void space.
    7.) Basement fires that have only one
    entrance. You'll intensify the fire
    and then not be able to make the basement
    stairs.
    As far as roof ventilation goes its still necessary. I agree with the earlier post about crew safety and not going to the roof if its ify. Not every house in your territory is brand new and built to burn. A good agressive Co. can be on and off with a large hole where it needs to be in a couple of minutes. Houses made of newer materials are a real threat though. A good rule to follow is this. If the fire has been free burning in the attic space for 10 minutes or more and the house is of new construction then don't go up top. From the time the occupant discovers the fire and calls you to when you go on scene is darn near 10 minutes sometimes. Now factor getting the ladder to make the roof, then the roof ladder, now get the saw and so on. If it is of new construction its already thru the roof or gonna be any second. Some indications during your size up to determine if the fire is in the attic.
    1.) HEAVY dark smoke coming from the eaves
    and from between the shingles. I mean
    dark staining smoke. Not light smoke that
    could be coming up from a trash can, food
    or something small.
    2.) Fire starting to poke out of the eaves
    or the base of ventilators.
    3.) No smoke ground level at all. Smoke will
    take the path of least resistence even
    though its heated. Some will up but some
    will also go laterally.
    4.) Occupant tells you its in the attic. But
    don't take their word on it alone.
    Everything I mentioned are just the things I have been taught or picked up on while doing the job myself. They are just something to consider. Size-up is key. Know your building construction. Be safe.

    Larry

  4. #4
    STA2
    Firehouse.com Guest

    Post

    Something I forgot to mention. Crew size should be no more 2 on residential and 3 on commercial. On and Off quick. No loitering on the roof after its open. If its bad when you get topside then tell command and get back to the ladder. The only thing worse than wearing a truss roof is to be part of a truss roof as it falls. Your cut should be over the fire if at all. Peek roofs are easy high and iver the fire. Flat roofs are different. Look for wet tar, spongy roofs, etc. Be safe.

    Larry

  5. #5
    resqb
    Firehouse.com Guest

    Post

    STA 2 is right, know your building construction. Finding out the building is balloon constructionby pressurizing the building and pushing fire up the voids is going to ruin what looks like a good knock down. Sudden fire everywhere but where you started isn't a good thing...Stay low

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