Photo By Frank Brannigan Photo R259 - This imposing looking building is a potential void-space backdraft and structural collapse hazard as we see in the next picture. Photo R260 - When we "undress the building", we see it's light weight construction of trusses and the interconnected void spaces. Do not be fooled by "light smoke showing. Fire may be spreading like cancer through the voids. When this slide was shown to truss proponents, I said firemen see a need to get on top of this structure and open a hole in the roof to let out heat and smoke so other firefighters can go into the building to extinguish the fire. The audience collectively gasped. For years, I have argued that firefighters should not be in or on a structure like this if the trusses are burning. Now the thermal detector, the Firefighter's Radar, can tell us what is happening. Somebody who recognizes this building in Upper Marlboro, MD may be able to tell me if it is sprinklered.
Photo By Frank Brannigan
Photo By Frank Brannigan Photo R245 - Sometimes the argument, "Our Trusses are engineered", is offered . This is supposed to quiet the protests of the "uneducated" firefighter. This is a typical engineering school competition, to see who can design a truss with the highest weight to load ratio. When I asked the professor at the University of Florida about firefighter safety, he replied "That's their problem, not ours."
We will continue our discussion of trusses in successive columns.