FIRE LOSS MANAGEMENT
DISASTER MANAGEMENT
Part 4: POWER SOURCE: ANOTHER “FRIEND” THAT CAN START UGLY FIRES
POWER FOR INDUSTRIAL or commercial functions is developed by motors that are usually electric but can be gasoline-, liquified petroleum gas-, or diesel-operated. They may operate intermittently or continuously, attended or unattended, in various combinations. The one simple precaution is to assume that a fire will occur, particularly where a motor operates unattended at a remote location.
Practically any electric motor that is run to the end of its service life will break down. This breakdown may or may not be accompanied by fire. If it is accompanied by fire, the sole fire loss management question is: “Will the fire extend beyond the motor?” If the fire is confined to the motor, there is no serious problem. The cheapest and best procedure is to cut the current, cool the motor by applying wet cloths, and remove it from the system. Don’t use $100 worth of CO2 on a S25 motor.
If the fire extends beyond the motor, there may be serious consequences. Tlie problem arises less often with ULlisted appliances in which the motor is generally built inside and enclosed than it does in equipment that’s locally assembled. Such equipment should be enclosed, with screening or wire, for example, to prevent kindling materials from being placed close enough to become ignited.
Sometimes compressors are located above or nearby cold boxes or lowtemperature rooms. These spaces are initially designed solely for the equipment and their motors but are inviting places to store other materials. Where does your local supermarket store its surplus paper cups, picnic supplies, paper napkins, and other lightweight, bulky, readily combustible stock? Look on top of the refrigerators. You may find these supplies close enough to the compressor motors to be ignited by a motor fire—and an insignificant fire becomes a disaster. Physical arrangement must prevent the storage of kindling-type materials close to any motor that might ignite them.
Motors on portable equipment can be a source of fire in a variety of ways. Several sailors in traction died in a WW1I naval hospital fire when a floor waxcr set fire to flammable wax.
In an area where flammable liquids are handled, only properly safeguarded electrical equipment should be installed or used. The motor of an unprotected device (the waxer) was introduced to the area temporarily. If an area requires explosion protection for the electrical equipment, all the electical equipment brought into the area must be so protected.
As I was wheeled into an operating room by hospital staff, I pointed to someunprotected electrical equipment which could have provided the ignition source for an explosive anesthetic-air mixture. “Mr Brannigan, please say a few words into my microphone,” said the anesthesiologist as he placed the cone on my nose and mouth. They never heard my zinger argument, “Opcrating room explosives kill the staff along with the patient.”
POWER SOURCE
(Photos by author.)
Automatic switches that turn the motor and lights on and off are another source of trouble. Take the electrical refrigerators that are widely used in laboratories. Solvents that give off flammable vapors even at low temperatures are often placed in the refrigerator, unsealed. The purpose of refrigerating the solvent is to retard evaporation. The evaporation is retarded but not stopped. A violent explosion can occur when vapors are ignited by the thermostatic switch as it operates to turn the compressor motor on or off. Whenever flammable liquids must be refrigerated, a proper, listed refrigerator must be provided.
In an actual occurrence of this nature, a batch of research mice were killed with ether, placed on a tray, and kept in a refrigerator. The cold contracted the mice’s lungs, freeing the trapped ether. During the night, the switch exploded the ether-air mixture and blew the lab apart. THE REVENGE OF THE NERDS.
The transmission of power involves friction. Belts and bearings, in particular can provide the friction—the heat— that can cause a fire.
The source equipment—driven by electricity, gasoline, whatever—should be examined from the point of view that a fire will occur but that the extension of the fire must be prevented. By stressing the control of the extension of the fire I do not mean to discredit attempts to control the cause of the fire itself. No reflection is cast upon programs to keep electric motors clean, in proper condition, and properly inspected. These are all necessary. By themselves, however, they will not guarantee that a destructive fire will not occur. A program that accomplishes the prevention of the extension of fire will provide a guarantee that a destructive fire will not occur.
Electrical power is most efficiently transmitted at high voltages. Transformers are provided to “step down” the voltage to whatever level is locally required. Like a motor, a transformer can die quietly or it can go out— literally—with a bang. Ideally, this possibility and the potential for tremendous damage should lead to the location of transformers where a failure could do the least damage.
Some years ago, the flammability of transformer coolant led to a nonflammable substitute, polychlorinated biphenyls, now familiar to us as PCBs, a known carcinogen. In 1982, a relatively small fire in a state office building in Binghamton, New York caused a transformer to release its PCB contents. The cleanup has cost more than the building, and there is a great reluctance on the part of employees to work in the cleaned-up building.
This concludes our very brief discussion of the three friendly causes of fire. Fires originating from these causes cannot be prevented by eliminating the cause; we need light, heat, and power. We must control their use, thereby managing the potential for disaster.
