A combustible roof helps fuel the spread of a massive 1953 fire at a GM plant
NFPA Journal®, March/April 2010
On the afternoon of August 12, 1953, at the General Motors Hydramatic transmission plant in Livonia, Michigan, a welder's torch ignited a conveyor's drip pan containing flammable liquid used as a rust inhibitor for transmission parts. Within minutes, the fire engulfed the entire 1,502,500-square-foot (139,582-square-meter) building, which contained 34 acres (137,600 square meters) of undivided space. The insulated metal deck roof began to collapse before the arrival of firefighters, who could do little but protect the exposures. By the time the fire burned itself out the following day, the plant had been destroyed.
It was the worst industrial fire in U.S. history until that time, and with a loss of $70 million, still ranks as the worst dollar-loss fire in automotive history, according to www.autotran.us. As the only plant manufacturing Hydramatic automatic transmissions for General Motors and several other car-makers, its loss could have devastated the company had it not scrambled to open a new production line at a former World War II bomber plant nine weeks later.
The rapid spread of the fire was due in large part to the plant's built-up roof, which consisted of tar and layers of roofing material installed on metal decking. According to Glenn Corbett, writing in the twentieth edition of the Fire Protection Handbook, such a roof appears noncombustible when seen from below because the tar is not visible. However, the tar "is capable of self-sustained combustion" and can vaporize, Corbett writes, as it did in the Livonia fire. Under pressure, this vapor "entered the building through the joints in the steel deck and burned inside," according to Peter Gore Willse, also writing in the Fire Protection Handbook.
Despite the speed and magnitude of this fire, there were only six fatalities. Four firefighters died during the operation, and two construction workers were electrocuted two days later while clearing debris. None of the plant's 4,200 workers were killed, and only 15 were seriously injured.
— Kathleen Robinson