Those open truss roof systems that you see in the big box retailers (Wal-mart, lowes, home depot...) are ridiculously dangerous in fires. The sprinkler spacing is too far apart, there are too few vents, AND THERE IS NO ****ING FIRE PROOFING MATERIAL ON ANY OF THE STEEL.
It's a recipe for disaster. I've been flatly told that some fire fighters refuse to enter those buildings (when it's on fire) for that reason alone.