Bus operations pose several challenges with passenger safety at the forefront. Whether a bus is for business, schools, or general transportation, if a fire occurs in a bus, it has the potential to be devastating. Preventative measures including regular inspections and maintenance, as well as pre- and post-trip inspections can reduce fire risk. However, if a fire does occur an automatic fire suppression system will quickly suppress the fire, minimizing damage and keeping passengers and the driver safe. Here is how a bus fire suppression system works.
1. Detecting a fire in the engine compartment
Bus fire suppression systems work by detecting and suppressing the fire before it spreads. Pre-engineered systems with non-electric detection do not rely on electricity and provide 24/7 protection. The system routes linear pneumatic detection tubing throughout the engine compartment to detect the fire.
Should a fire start in the engine compartment, the increase in temperature or direct contact with flame will cause the tubing to burst, releasing pressure on the cylinder.
2. Discharging suppression agent
The change in pressure signals the system to discharge the agent through strategically placed diffuser nozzles, flooding the engine compartment quickly to suppress the fire. An optional system indicator is available and alerts the driver the system has activated or requires servicing.
3. Suppressing the fire
The recommendation for engine fire suppression systems is the use of ABC Dry chemical because of its effectiveness in suppressing Class A, B, and C fires. These fires hazards may originate from fuel leakage, faulty electrical connections, short circuits, or hydraulic hoses. From a system standpoint, there is no difference in suppressing a diesel, gasoline, LNG, or CNG fire.
Are automatic fire suppression systems required for buses?
While the National Transportation Safety Board (NTSB) does recommend that all new and in-service school buses be equipped with automatic fire suppression systems, there is not a current regulation that requires it within the U.S. With an average of 4-5 of bus fire occurring daily in the U.S., a fire suppression system provides an additional layer of protection.