Gene P. Carlson’s Volunteers Corner
Trucks, the major means of transporting cargo in North America, are a source of fire problems. Fire incidents can be classified by the location of the fire in the vehicle or by the type of truck. Due to the wide range of possibilities when discussing cargo, tank, and open-body trucks, this discussion will be limited to the location of fires in trucks.
Truck fires will occur either in the engine/cab area or in the area carrying the payload. The major problem in the engine/cab area has to do with the fuel supply. Generally, gasoline and diesel will be found, but liquefied gases and compressed natural gas are also in use. The amount of fuel will vary up to 400 gallons on over-the-road transports. It’s important to control these fuel fires quickly to protect exposures, especially the cargo area and such special highway features as bridges. Liquefied and compressed fuel tanks will need immediate cooling, if exposed to fire, to assure the integrity of the vessel and maintain scene safety.
The cab area has several combustibles that produce very toxic products of combustion. These include plastic trim and dashboards, wiring insulation, seat materials, and, in larger units, the contents of the sleeping compartment. In cold weather, diesel units may have a can of ether to assist starting. This should convince every first-in officer to require self-contained breathing apparatus and a minimum of a 1 Viinch hoseline (two-inch would probably be better).
Engine compartments may be the “sleeper” in a truck fire. There are several small, seemingly insignificant components that, under heavy fire conditions, can rupture with an explosive force. These include hoses, tubing, and reservoirs. Many of the products are flammable, toxic, or both. As they burst, they can spew the liquid on unsuspecting firefighters, or create dangerous flying pieces as a result of the boiling-liquid, expanding-vapor explosion.
If the fire is in or has extended to the cargo area, the first effort should be to identify the contents of the vehicle. Since hazardous materials can be present — often legally unmarked — it’s a must for the officer to secure the shipping papers from the driver and determine the potential hazards posed by the load.
Based on the contents, amount and extent of fire, and exposures, the size of the attack line can be determined. Larger lines shouldn’t be ruled out. Haz mats may require special extinguishing agents in large quantities. Water supplies are often remote or difficult to reach, as is the case on limitedaccess highways.
Plan for operations that will provide adequate quantities of water to probable, often characteristically difficult locations of truck fire incidents.
There are several miscellaneous items on trucks that cannot be overlooked.
- Tires: Tires may rupture when exposed to fire, throwing burning pieces of rubber, fabric, and steel belts. Tires may also be the fuel itself. They should be removed and extensively cooled due to their ability to hold heat and reignite. Check for the spread of fire from the tire to the cargo area.
- Brake fires: Brake fires are similar and require careful cooling to limit drum damage. Again, check the underside of the cargo area to ensure that the fire has not spread.
- Air bags: Many units are now equipped with air bags for suspension. During a fire these can rupture and allow the unit, tractor, or trailer to drop as much as eight inches. Remember this at all times when working on such vehicles; keep your body away from a potential drop. This is especially significant around wheel wells, where a firefighter could get caught between the trailer body and the tire.
- Magnesium components: Many large units have components made of magnesium. These include bumpers and frames. If they become involved, large quantities of water will be required to cool the magnesium pieces below their ignition temperature.
Positioning at truck fires is very important. A major consideration in positioning is the type of truck and the cargo. The approach route will sometimes dictate the placement. Traffic, wind direction, topography, water supply, and exposures are important parts of the size-up.
Ideally, pull the apparatus past the burning truck, and park it on the emergency shoulder. Attempt to keep the pump operator and attack lines away from traffic exposure. DON’T PARK TOO CLOSE! Parking in front allows the officer to see the entire truck, alleviates problems of blocking doors that may need to be opened, and allows members of the engine company to place themselves between the fuel tanks and a trailer fire. However, if the wind is blowing forward or the situation has deteriorated to the extent that separation of the tractor from the trailer is required, parking to the front may not be the best approach.
Before initiating the attack on a truck fire, the officer must make a thorough size-up, considering the many variables.