Automated Fire Suppression Offers Early Detection, Minimal Maintenance

Fire suppression systems have been an equipment option for transit and school buses for years. But, the decision to mandate the systems on school buses is heating up — especially given the National Transportation Safety Board’s (NTSB’s) recent recommendation to require the systems on all school buses.

Even before the NTSB’s recommendation, states and pupil transporters had been making strides in adding fire suppression on their buses for additional student protection in case of a thermal event.

Currently, New Jersey and Georgia require the technology on all of their special-needs buses. Meanwhile, Nevada requires it on all of the state’s school buses.

In 2016, National Express, the second largest school bus contractor in the U.S., began adding Fogmaker’s fire suppression systems to its entire fleet.

More recently, Mobile County (Ala.) Public Schools also announced its plans to deploy the supplier’s systems on all 100 of its special-needs school buses, and it eventually plans to add the system to its remaining 600 buses.

More school transportation operations are looking to adopt fire suppression technology, and many suppliers offer systems that can help enhance speed of fire detection, reduce overall vehicle damage, and require minimal maintenance.

Targeted Approach

Kent Tyler, executive vice president of Fogmaker North America, says fire suppression systems are designed to target three key aspects of a fire: oxygen, heat, and fuel.

To efficiently target all three, suppliers note the importance of having automated systems that require no electrical input or additional action from the school bus operator.

“Automatic systems typically actuate and suppress fires long before an operator can realize a fire has occurred and manually actuate a suppression system,” says Marc Dinovo, the senior applications manager engineer for Firetrace.

Fogmaker’s high-pressure water mist design allows the system to deploy in any circumstance, a school bus overturning being one example, Tyler says.

The same goes for Firetrace’s system, which contains a linear pneumatic fire detection tube that can expel nitrogen — creating a pressure differential that can initiate the discharge of the system’s fire suppressant.

Fire-Gator also performs total engine compartment flooding, but instead uses Stat-X’s aerosol fire suppression system.

“Our Fire-Gator system works automatically for school bus applications, and the aerosol suppressant in the system is environmentally friendly, unpressurized in the ready-state, and is not harmful to the operation of the engine,” says Brian Lyons, managing partner of Fire-Gator. “Once the system detects the fire, the aerosol agent is uniformly distributed without using any pressurized tubing. The system creates its own discharge pressure that disperses the agent through its incorporated nozzle and discharge ports.”

Early Detection

On average, a fire suppression system can detect thermal events within about 25 to 30 seconds.

To minimize overall vehicle damage, Matthew Clapp, the OEM account manager for Kidde Technologies, says that early detection should be conducted through active alerts to drivers and consistent vehicle monitoring.

“With fire suppression, we’re trying to notify the driver as quickly as possible so they can quickly evacuate the vehicle and get students safely off the bus,” Lyons adds. “Fire-Gator can signal out to the bus shop from the vehicle’s OnStar, and the system also has the ability to offer hub protection whenever it’s deployed.”

In addition, Clapp says some districts have requested that suppliers add automatic engine shutdown as a feature for post-fire detection.

“From a fire suppression perspective, Kidde Technologies always recommends shutting the engine off,” Clapp says. “If one of the sources of the fire is a fuel or oil spray, the last thing you want is to continue to have the engine running to continue to provide fuel for the fire.”

While the automatic engine shutdown feature depends on the supplier, Clapp says some districts are hesitant to implement it — underlining their concerns about rendering buses immovable at potentially dangerous locations, such as if a bus were stopped on a railroad crossing.

Minimal Maintenance

Even though fire suppression systems require little to no maintenance, Firetrace’s Dinovo says it is still essential for technicians to be aware of how to sustain the system. More importantly, they should know what to do after the system has been deployed for a thermal event.

“I cannot stress enough the importance of educating operators and technicians on not only how these [fire suppression] systems work, but also how to spot potential fire hazards before they have a chance to become one,” he explains. “I have seen operators ignore system warnings simply because they did not know what the warnings were for. Additionally, I have seen maintenance technicians ignore large amounts of debris, such as road gunk, grease, and oil, near ignition sources simply because they don’t perceive it as a hazard.”

Depending on the type of fire suppressant a system deploys, whether it’s a liquid- or powder-based solution, Tyler says technicians should make sure that the suppressing agent isn’t going to “eat away at their wiring harness” or cause any additional damage to the bus’s engine compartment.

For example, Fogmaker uses an aqueous film-forming foam (AFFF) that can suppress a fire. Meanwhile, Kidde Technologies uses a non-corrosive purple dry powder that allows technicians to clearly see where the powder has been distributed, making for a quick and easy cleanup, Clapp explains.

Fire-Gator seeks to cut down on maintenance time and costs by using an aerosol suppressant, Lyons says. He adds that Fire-Gator offers recommissioning services in which technicians come out to replace the system’s generators and the area of the detection wiring that has been compromised.

Increasing Adoption

While the NTSB’s recommendation may have reignited the discussion about fire suppression, several other legislative actions, such as the push for seat belts on school buses across the U.S., are also fueling the use and growing adoption of the technology.

In July, two federal lawmakers re-introduced the School Bus Safety Act, which aims to improve school bus safety by requiring lap-shoulder belts and other safety technology, including fire suppression systems, on buses.

“We’ve seen a lot of transportation directors and industry officials become very concerned about adding seat belts on school buses,” Fogmaker’s Tyler explains. “From a fire suppression standpoint, it will take longer to get children off a bus equipped with seat belts, so more districts are looking at fire suppression to increase the amount of time they have to evacuate students.”

Although seat belts remain a divisive issue in the school bus industry, Tyler adds, he hopes it will continue to spur the conversation on fire suppression and make school districts aware of the solution, which is designed to not only buy them time in the event of a fire, but also save lives.