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Truss and Stick Built Roof Burn Tests

With the recent death of Dallas Fire Lt. Todd Krodel, and his tragic fall through a roof while attempting to vent it, I am going to post a few of my thoughts about roof ventilation. Again this is not to point fingers at anything the Dallas FD, or Lt. Krodel did wrong but to take this instance to focus on something that we may not think about everyday and reinforce it to increase or fireground operations, and safety.

I thought the video below would be a great place to start. In it you see 2 burn tests down by a students from a fire science program. You get a description of the “Truss Roof” and “Stick Built” roof construction. Then you see that during the burn tests the “Truss” failed in 5 mins, and the “Stick Built” failed in 17 mins.

While this is a great test and can give a baseline we need to take it a step further. The burn tests were conducted with class A combustibles, so is the test fully accurate of what we are facing out in the field. Go into your attic and pick out how many class A combusitbles are in your attic. While there are some Im sure it is more on the side of plastics, foam, PVC etc. which as we know have higher heat release rates and cause fires to progress faster. So the time to roof structure failure could be significantly reduced based on the involved combustibles.

Second response time and staffing play a huge role into whether ir not venting the roof is right for your department. In my career department even with 20 engines, 5 trucks, and 3 squads all staffed with 3 person crews and pretty fast response times we would be pushing it to get to the roof in time to vent a “Stick Built” type roof, with class A combustibles only involved (using the aforementioned 17 min time frame). In my Part Time department with 2 person crews no ladder truck and possibly 10-20 min response times venting the roof is not an option almost ever.

We must not only take into account what our fire is doing, but where we are, how fast we can get there, and who we have in order for this operation to be succesful.

Do you know what types of roofs are in your district? If you do not then how do you know what sort of challenge is awaiting you? Always inspect the roof structure of an occupancy any chance you get, and on a residential fire alarm, check the attic even if you do not think the problem is there just to get that look.

Stay Tuned for subsequent roof vent posts!

As usual thanks for reading, spread the word, and STAY SAFE!

[vodpod id=Video.15260779&w=425&h=350&fv=%26rel%3D0%26border%3D0%26]

 

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