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## Chapter 22 Structural Collapse Such as a heavily loaded floor. Each indicator taken separately might not raise sufficient alarm to provoke the evacuation of personnel; however, when viewed as a whole, they could be warning signs that the building is in danger. For this reason, it is critical tha...

## Chapter 22 Structural Collapse Such as a heavily loaded floor. Each indicator taken separately might not raise sufficient alarm to provoke the evacuation of personnel; however, when viewed as a whole, they could be warning signs that the building is in danger. For this reason, it is critical that the officer in command promptly receive notification of each and every one of the following indicators of potential collapse. ### 1. Occupancy by problem businesses We know from past experience that certain occupancies present unusually heavy floor loads. Plumbing supply stores, appliance dealerships, and printing shops all have large concentrations of heavy items. Other occupancies, such as supermarkets, car dealerships, bowling alleys, and churches, tend to have truss construction. Each of these conditions should be viewed as a red-warning flag. Although the type of occupancy alone isn't reason enough to withdraw all forces, it should trigger a careful examination for additional *signs* of possible collapse. ### 2. Construction Of all the other possible warning *signs* of collapse, there is only one more serious than the presence of truss construction— a structure that contains explosives. Fortunately, fires in explosive occupancies are rare. Moreover, they are usually over before we arrive. Fires in truss-construction buildings, however, aren't so rare and, in fact, are probably going to become the fire problem of the 21st century as the buildings of today begin to deteriorate. A new style of firefighting will have to emerge to combat fires in these structures. (Or maybe it's not so new. It involves standing back and lobbing water from outside the collapse zone at any fire that seriously involves the trusses.) Other new styles of lightweight construction, such as particle board *I*-beams, will deserve the same technique. Always bear in mind that the designers of these products, the builders who put them in, the code enforcement *agency*, and the insurance companies that tolerate their use don't care a bit about the effect that their collapse will have on a firefighter. Their concerns are with the bottom line (fig. 22-18).