Fans and PPV

[oldstyle]

As a department, we use positive pressure ventilation for residential fires. WHEN to turn the fans on is another matter. My truck waits only until a charged hose is ready to enter. The truck in the next zone waits until the fire is located and water is actively flowing. I understand the logic behind each method. What is your policy or personal preference?

[nsb22]

We have yet to try PPV during attack. We were supposed to try it out next weekend on a practice burn, but the city lost the house. We ALWAYS use it after the initial nock down though. A couple of our guys went to a class on it, but I haven't seen them to ask how they liked it.

[MrWithasee]

My dept. is a litle behind when it comes to advanced ventilation techniques. As a matter of fact, its behind the times on ladder company ops. in general. But that's beside the point. We have a new crop of leadership coming into play who want to change that - and other things.

We have tried the PPA technique on some acquired structure training burns. It definatly requires a lot of comm. between the fire attack company, the ladder guys at the front door with the fan and an exterior crew ready to take out windows.
We worked it like this

Charged hoseline enters the house and locates the fire room
Exterior vent team takes out the window
The fire is attacked directly
The PPV is started

All but the first thing have to happen at the same time. Hence the communication. Easier said than done. The comm. difficulty is one of the main things that makes this contiversial. Its easy to burn somebody's house down (or kill a fireman) if it doesn't go right.

[hotpig]

We started using it about twenty years ago. It sure makes house fires a breese. It is nice to walk upright to the fire room spray for a minute and start the overhaul.

The team has to be ready because the fire will grow fast once the fan starts.It will not work if people are smashing windows left and right(I was a career firefighter for almost seventeen years before I broke out my first window at a real world fire). The IC must make sure that the vent,fan, and attack crew are all ready.It can be done after the attack team has started, but it negates the advantage of clearing the smoke and heat for the attack team.

On small building it works so well I can actually walk in behind the attack team and start the cause and origin.

[Tvov]

We always use PPV. As people have said, communications are important. Also, as hotpig pointed out, you can't really break out all the windows. You have to figure out were to vent to allow PPV to do the most good.

We usually start the attack, and then start PPV almost immediately if we can after communicating with the attack squad and a sizeup of the fire.

A few years ago, I went on a mutual aid in a neighboring town. The FD there tried to vent the attic by the "old" way, having a fan in the attic window sucking air out. Took forever to be effective, actually never really vented the area. Being a mutual aid company, we weren't comfortable saying anything. After that call, I try to subtly mention trying PPV at mutual aid calls.

[hotpig]

I noticed years ago the City Departments claimed to try it but it did not work for them. The biggest problem was they took out windows all around the building. Other problems could be that there is a door closed in the building some place between the fan and the vent hole. The building just may be too big and it will take time to clear the heat and smoke.

A demo that you can do at the Station right now in less than five minutes.We do this to show the probies why they should never take a window out unless ordered to do so by the IC.

I set the fan outside of the front door. Hang some sheets of toilet paper from the top of the door frames starting from the fan going to the back bedroom. I hang tp on the bedroom window.

Open the window and start the fan.You can watch the air movement by following the blowing tp. You can shut a interior door between the fan and vent or open other windows to demo the negative effects that it can have on ppv.

[oldstyle]

Originally posted by hotpig
It sure makes house fires a breese. It is nice to walk upright to the fire room spray for a minute and start the overhaul.
That's the theory my station uses. Once the fan is on, it only takes a moment for visibility to improve and the fire is then quickly located by the hose team. The hose doesn't have to wait on the fan if the truck isn't on scene yet but the fan always waits for the hose to be on scene, charged and ready to enter.

[kyfirefreak]

Policy wise, its the OIC's call.

My preference, as ititial attach is being made, going w/ hotpig's statement.