A fire with much loss of life and property, like the recent one at Grenfell Tower in London, captures international attention. And in particular, fires in high-rise buildings are high-profile events. Perhaps they suggest the possibility of greater disaster due to the sheer building size. A high-rise fire was the core of the plot in a top-grossing film, The Towering Inferno. Nevertheless, life and property damage from fire is, on average, significantly less in high-rises than low-rises. The reasons underscore the factors at work in fires and how FMs can best manage the risks.
The likely place of origin of a fire is much the same in both commercial high-rise and low-rises. According to the National Fire Protection Association (NFPA), a kitchen or cooking area is, by far, the single most likely place. In high-rise structures, a kitchen accounts for 76% of fires in apartments, 40% in hotels, 65% in dorms and 31% in offices. In low-rise structures, those percentages are very similar.
What differs is the likelihood of fire spread and damage beyond the place of origin. Low-rises are more than twice as likely as high-rises to have fire spread. In apartment structures, only 4% of high-rise cases have fire spread but 10% of low-rises do. NFPA reports similar figures for other property types. In hotels, 4% of high-rise fires result in flame spread but 11% of low-rise fires; in office buildings, it is 10% vs. 21%. In turn, the fire death rate and average property loss per 1,000 fires are generally higher in low-rises than in high-rises of the same property type.
NFPA theorizes that high-rises are more likely to have fire-resistive construction and wet pipe sprinklers to limit flame spread. Exceptions can be costly. In the fire at the former MGM Grand hotel in Las Vegas, which killed 85 people, sprinklers were not installed in the restaurant where the fire began. The reasoning of building inspectors was that spaces that were occupied 24/7 did not need them—a fire would be discovered quickly and put out with portable fire extinguishers. Unfortunately, the restaurant was closed when vibrations from refrigeration equipment frayed the insulation on electrical wiring. Moreover, one cannot be sure that fire bottles will work when needed. In the early minutes of an arson fire that killed eight at the former Las Vegas Hilton, a faulty extinguisher defeated the efforts of a hotel security employee.
Anticipating where fires are most likely to occur is clearly important, as are inspection and maintenance of fire systems. Last month, NFPA released a report on the effectiveness of sprinklers. In the 12% of fires in which sprinklers failed to operate or operated inadequately, the majority of cases involved damaged system components, deficient maintenance or—incredibly—the system was shut off.