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## Building, Threatening Lives Unfortunately, not all fires are going to succumb even to this superior stream. In large-floor-area offices, particularly those built with core-construction techniques, a complete burnout of the floor may result of a large volume of fire is present on arrival. Co...

## Building, Threatening Lives Unfortunately, not all fires are going to succumb even to this superior stream. In large-floor-area offices, particularly those built with core-construction techniques, a complete burnout of the floor may result of a large volume of fire is present on arrival. Core construction is the practice of grouping all of the nonrentable spaces—stairs, elevators, lobbies, electrical, airshafts, and the like—in a central core, thus leaving The more desirable perimeter as open floor space. This practice provides floor spaces in excess of 30,000 sq ft per floor. The result is that, if a fire gains major headway, it can easily spread to the entire floor (fig. 18-34). (Each floor of the WTC measured 208x208 Fig. 18-34. A fire of this magnitude on a center core floor this Will require a substantial commitment of personnel. If the fire cannot be stopped at this stage, and it involves the entire floor, it is likely going to have to be contained, while being allowed to burn down to a reduced intensity. Even if we assume a light fire load, requiring only 0.10 gpm per sq ft to extinguish, we can see by multiplying 40,000 by 0.10 that at least 4,000 gpm is required to extinguish a fully involved floor of this size. Prior to 1993, NFPA 14 only required a standpipe system to be designed to supply a maximum of 2,500 gpm. In the 1993 revision to NFPA 14, that number was lowered to 1,250 gpm! Maybe that's a good thing, in light of the potential for collapse of lightweight