Thread: PPV techniques
06-21-2001, 10:45 AM #1Anthony MattinglyFirehouse.com Guest
I am looking for input on using positive pressure ventilation for structural fire attack. Currently we use PPV after the fire is knocked down. We have read articles about using in conjunction with knockdown as the hose line goes in. We have read that this works good in clearing the products of combustion and have also read that this is a risky evolution and may spread and feed the fire and do more harm than good. All input would be greatly appreciated.
06-21-2001, 11:03 AM #2Anthony MattinglyFirehouse.com Guest
Sorry folks I posted this topic before I read the other post on PPV fans. Still if you have any additional info please share.
06-21-2001, 12:54 PM #3Dalmatian90Firehouse.com Guest
One thing to add...
We're generally directed to setup the PPV fan -- but not aim it at the building. Carry it over, get it started but leave it facing 90 degrees (or what's convient) away from the building.
While we're positioning and starting the fan, the OIC will verify with the other officers that conditions are OK for PPV and then gives the order to turn the fan into the building to start PPV.
06-21-2001, 06:03 PM #4570eckFirehouse.com Guest
PPV is a great tool but can produce much havok if not used right.
A couple of basics. First your vent hole needs to be smaller than your entry hole. This is what creates pressure, air enters and is pushed thru the smaller hole but since the smaller hole can not move as much air as the larger one you create pressure. As you progress thru the fire building close any doors that do not have fire envolvement. This will help build the pressure and will do it quicker since there is less of an area to "charge". You must know exactly where the fire is and where it is going. If a fire is spreading into an attic or open area all you serve to do with ppv is push it along. You should have good knowledge of fire travel. Fire travels the path of least resistance so it will head for open air this should be your vent hole. Before you start your venting you should have a line in place, or you are just "adding fuel to the fire". If there is an attic or cockloft area you should have a line in that area as well to prevent any spread to that area.
PPV is great because it keeps advanceing crews cooler because heat is being pushed away. But like I said it can cause havok. These are just some of the bascis to PPV. If you realy want to attempt PPV, all the people who will be involed with it should go to school for it. Take the time to go to a burn building/school and practice as much as possible. If not done right someone can get realy hurt.
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