Vent tactics taxpayers/big box

[windswept]

With all the new lightweight steel roofing systems on taxpayers and big box stores ,and the dangers they pose with vertical ventilation, how are your departments tactics/SOPS addressing getting them vented during fire operations.

[jonnyirons2]

You cant vent a building usually with a truss roof. The roof is made of q decking, and usually covered to deaden the sound of rain and insulate from the sun. Hopefully the inside team will take a look with a hook as soon as they get in to determine the construction and if its truss or heavy timber. Usually a good idea is to look and see if you can see any columns, that would possibly signal that its an I beam support system and that you can possible find a way to vent above, but thats all depending on the overall size of the building.

[LFPDLT]

Your best bet is going to be skylights and natural openings if available. Ventilating a Q-deck roof can be very labor intensive, a standard 4x4 hole is going to be ineffective on a 500x200 ft. building and a large enough hole is going to take too long to cut. The catch 22 with these buildings is that if you can safely cut a proper size hole in relation to the building size you probably didn't need it, and if you really need the hole you can't safely cut it. The other problem is that many times these buildings are sprinklered and operating heads will make vertical ventilation pretty useless, you need heat and upward thermal movement for a hole to be effective and this pretty much kills that effect. With the quick failure rate of these roof assemblies more often than not vertical ventilation will not be feasible.