A vehicle fire can start under a variety of circumstances, including abrasion against a hydraulic line that results in a hydraulic fluid leak or a short in the electrical cables.
Among the benefits of installing fire suppression systems on school buses is the potential for reducing vehicle insurance rates and premiums, preventing the total loss of the vehicle and reducing damage to equipment, and most importantly, preventing injury to the bus driver and passengers.
"You get less than five minutes to completely evacuate a vehicle. In fact, sometimes in only a couple minutes, the smoke is too intense and the fumes too bad to survive," says Joey Peoples, manager of Kidde's commercial ground vehicle group. "Yes, there are a lot of children on a school bus, but by far, the big risk is if you have a fire with handicapped people on board — the amount of time it takes to get them off the vehicle is much greater than it is for those who have better mobility."
School bus fleet operators are sometimes resistant to installing automatic fire suppression systems on their vehicles, Jomarr Products Inc. Vice President Mark Perrella says. "But when you're purchasing a new school bus with a base cost between $75,000 to $100,000, the cost of an automatic fire suppression system is relatively insignificant," he says. "Considering the potential consequences of a school bus fire, the installation of an automatic fire suppression system is not a luxury item or an unnecessary, frivolous expense. It is a very important safety feature."
Amerex Corp.’s fire suppression system cylinders are constructed of steel and coated with an epoxy primer and polyurethane top coat for resistance to corrosion.
Amerex's Phil Anania, vice president, vehicle system sales, says that with many systems on the bus market currently, one of the company's greatest strengths is in its experience and its service network. "We have distributors nationwide buying our systems and installing in school districts across the country," he says.
Fire detection can be provided by fixed temperature thermostats and linear or Safe-IR detectors. Any combination can be used as necessary. Fire suppression agent is delivered to hazard areas by fixed high-capacity, fast flow, machined brass nozzles.
“It’s fully automatic, so it doesn’t rely on the operator making any kind of a call, whether he or she should push the button,” Anania says. “All the driver has to worry about is getting the students off the bus.”
The vehicle fire suppression system cylinders are constructed of steel and coated with an epoxy primer and a polyurethane top coat for resistance to corrosion. The valve is brass and features a brass gauge guard to protect the pressure gauge in rugged environments. Pressurized cylinders are shipped filled with ABC or Purple K dry chemical, and are available in 13-, 25- and 50-pound sizes. The systems are approved by Factory Mutual, a third party product testing and certification organization.
“We realize that the budget for maintenance comes out of the local school district’s direct budget,” Anania says. “One thing that we’ve learned is that they need to keep the maintenance expense low.”
To that end, Anania says that after the Amerex system discharges during a vehicle fire, the dry chemical in the agent cylinder and the electric actuator must be replaced and the hose delivery system needs to be blown out. “The whole process takes about 45 minutes.”
Fogmaker North America
USSC Group Inc. subsidiary Fogmaker North America’s Fogmaker system extinguishes fires with water mist, making it an environmentally friendly choice and eliminating some of the concerns surrounding clean-up.
Fogmaker’s high-pressure water mist chokes out an engine fire by removing the oxygen, says Ted Dowling, director of commercial sales and business development. “In demonstrations we do for people, we light a fire in an engine simulator booth and then we spray diesel in the booth and get the temperature up to about 1,500 degrees Fahrenheit. Then we put the fire out,” he explains.
When the Fogmaker system goes off, it sprays water mist for 70 seconds to cool the engine compartment and prevent the fire from reigniting, an additional 35 to 40 seconds longer than other systems, Dowling says.
“There’s minimal damage, because we’re taking away the heat that would damage the engine,” he points out. As a result, determining the ignition point and cause of the fire is easier.
In addition, fans in the engine compartment are placed to direct the water spray, especially because of the air flow through the area. After being discharged, the system can be recharged by mechanics in the bus garage, rather than a local fire extinguisher shop, meaning a minimal refill cost.
Fogmaker provides the recharging apparatus and technician training on the system. “They would recharge it in the vehicle — they would have to blow out the lines, but that’s it,” Dowling says.
The system’s fire detection components don’t require any power, and the fire suppression system can function in any orientation, Dowling says. “If the bus was on its side or upside down, our system would still work,” he says.
Because Fogmaker uses water, there is no hazardous material disposal required after the system is discharged.
“It’s a patented technology we brought over from Europe,” Dowling says. The systems are used in mining and military applications, with growing use seen in the renewable energy sector in wind farms, where the hydraulic-controlled turbines require fire protection.