Here is a video with interviews of the people involved in the Arizona training fire flashover. Have a look and come back.
A friend of mine on Facebook posted the first video with the notion that PPV is extremely dangerous and kills firefighters. The video was the proof of the argument.
The video above, which I didn’t find until recently, expresses exactly what I thought about the situation. Dave Marshall, the training officer at the time, stated “I think what happened is, we didn’t recognize that the fire environment was as close to the flash-over point as it was” and he is absolutely correct.
They were extremely lucky that no one was killed, and there were only minor injuries.
Positive Pressure ventilation is a tool. Like any other tool it can be used incorrectly.
IFSTA Essentials of Firefighting 5th edition provides some help with how to use PPV.
- As long as the pressure is higher inside the building, the smoke is forced through the ventilation exit opening.
I am not sure where their ventilation exit opening was, though it looked like it was the same window where they were spraying water from the outside.
- A blower is placed about 4-10 feet outside the open entry point so the cone of air from the blower completely covers the doorway opening.
The smoke billowing out from the door way after the blower is started tells me that the entire door was not covered by the cone of air.
- To maintain the positive pressure inside, it is important that no other exterior doors or windows are opened during the positive pressure ventilation operation.
With acquired structures it can be difficult to make sure all the windows and doors are in place. During this video you can see broken windows on the front porch where smoke is exiting the structure.
- PPV requires good fireground discipline, coordination and tactics
Additionally it requires excellent situational awareness. The on scene instructors became complacent and were not monitoring the fire. They were extremely fortunate that everyone was able to walk away and learn a valuable lesson from this event. Take this to heart, learn from their mistakes. Make sure everyone goes home, every day.
My Opinion, don’t use PPV unless you know where the seat of the fire is located. I am a firm believer in the use of vertical ventilation when possible. Attempting to use PPV in a fire of unknown origin is a good way to get the foundation ready for a new house.
This is part 2. You can read part 1 here.