Stopping a Fire Before It Spreads: Fire Extinguishers in Buses, and the Protection System Worth Taking Seriously
Vehicle fires happen often enough, and for a range of reasons: engine trouble, gas systems installed below standard, an ageing vehicle, an accident. Which is why the Department of Land Transport issued requirements for fitting fire extinguishers, with an eye on travel safety, and particularly on buses, the most widely used vehicle for carrying passengers.
The Department of Land Transport's notice sets out the following for buses and other passenger transport vehicles:
At least two fire extinguishers have to be fitted, one at the front of the vehicle and one at the rear, both mounted inside the vehicle where they can be reached and used quickly.
Beyond the extinguishers themselves, a vehicle also needs an emergency exit door and a glass-breaking hammer, so that people can get out in time during an emergency and the losses stay as low as possible.
Why does a bus need fire extinguishers?
A bus carries several systems that can be tied to fire risk:
The engine system
The fuel system
The electrical system
Batteries
Wiring and connection points
The engine bay
Electronic equipment
The air conditioning system
Interior materials in the passenger cabin
If a fire starts, having an extinguisher within easy reach and ready to use may let the driver, or anyone trained to use it, respond quickly before the fire takes hold.
Understanding where a fire starts and what keeps it burning is worth reading alongside this. See Elements of Fire.
The main fire risk points on a bus
Designing fire protection for a bus should start by working out where a fire can actually break out.
1. The engine bay
This is the area that deserves the most attention, because it holds:
The engine
Oil and other related fluids
Electrical systems
Heat coming off the engine
Pipework and various components
If a fire starts in the engine bay, getting to it with an extinguisher may be difficult. So the mounting position and the way anyone would respond both need thinking through.
2. The electrical system
A bus carries a great deal of electrical wiring: control systems, lighting, air conditioning, and electronic equipment.
An electrical fault, a short circuit or heat where there should not be any, can be one of the causes that leads to a fire.
Because any agent used around live electrical equipment has to be non-conductive, What is Non-Conductive (Dielectric)? is worth reading before choosing one.
3. Batteries and energy systems
An electric bus in particular carries the added risk that comes with a high voltage battery system.
The same distinction that applies at a charging point applies here. See Fire Suppression for EV Charging Stations.
Where should extinguishers be fitted on a bus?
The mounting position matters as much as the type of extinguisher.
The principle is simple: it has to be easy to see, quick to reach, and possible to pick up without getting too close to the fire.
Positions worth considering:
Near the driver. Somewhere the driver can reach quickly.
In the passenger cabin. If the vehicle design allows it, additional equipment can go where passengers or staff can reach it, as long as it does not block the aisle or the escape route.
Near the engine bay. Think about how someone reaches the extinguisher without having to get close to flames or high heat.
PAF-222 and fire protection on buses
PAF-222 (FK-5-1-12) is worth considering as an option for protecting areas or equipment that suit a clean agent system, particularly where residue after a discharge has to be kept down.
Areas where its suitability could be assessed include:
Control cabinets
Electrical cabinets
Control cabinets for specific systems
Dedicated equipment rooms or compartments
Electronic systems where residue has to be kept off the equipment
The passenger cabin area
For the passenger cabin specifically, PAF GLOBAL supplies two products built for it: Fire Suppression Systems for Passenger Cabins and Public Transport, and the Cassette-Type Fire Suppression Cabinet HTKD-CFXS-01.
For portable units, see the PAF-222 Clean Agent Fire Extinguisher (MJZ Series). For a localized automatic device inside an enclosure, see the Automatic Temperature Detection Clean Agent Fire Extinguisher (PZGW Series).
How to approach fitting extinguishers on a bus
Six steps will get you most of the way.
1. Survey the risk points
Identify the areas:
Engine bay → electrical system → batteries → passenger cabin → electronic equipment
2. Choose the type of agent
Match it to the class of fire and the equipment being protected.
3. Set the number and the positions
They have to be reachable quickly, without blocking an aisle or an exit.
4. Put up signage and instructions
Anyone who might use one should know where it is and how it works.
5. Inspect and maintain
An extinguisher has to be in working order and inspected according to the requirements that apply to it.
6. Train drivers and staff
The person using the equipment matters as much as the equipment. A driver, or whoever is responsible, should know the basic sequence:
Stop the vehicle → assess the situation → report it → evacuate → use the extinguisher once it is safe to do so
What to read next
What is PAF-222?
PAF GLOBAL's clean agent products and where they are used in practice.Fire Suppression Systems for Passenger Cabins and Public Transport
Built for passenger cabins, public transport and enclosed spaces needing precision and a high safety margin.Cassette-Type Fire Suppression Cabinet HTKD-CFXS-01
A compact cabinet system for passenger cabins and public transport.PAF-222 Clean Agent Fire Extinguisher (MJZ Series)
Portable units in several sizes, for areas where residue after a discharge is unacceptable.Automatic Temperature Detection Clean Agent Fire Extinguisher (PZGW Series)
A localized automatic device for small enclosed or semi-enclosed spaces.What is Non-Conductive (Dielectric)?
Why non-conductive properties matter when the fire involves live electrical equipment.Elements of Fire
Fuel, heat, oxygen and the chain reaction, and how each one shapes the choice of agent.Fire Suppression for EV Charging Stations
For anyone weighing lithium-ion battery risk and thermal runaway.What Certifications Does PAF-222 Have?
Including the marine and transport approvals, RMRS, IMO MSC/Circ.848 and MSC.1/Circ.1267.Contact for Consultation
To have the PAF GLOBAL team assess a vehicle or a fleet.
Frequently Asked Questions (FAQ)
1. Does a bus need fire extinguishers?
It should carry fire equipment that meets the requirements and standards applying to that class of vehicle, with the type, the number and the mounting positions all chosen to suit.
2. Where should extinguishers be fitted on a bus?
Somewhere visible and easy to reach, near the driver or at the points set by the vehicle design, without blocking an aisle or an escape route.
3. Can one extinguisher deal with every kind of fire on a bus?
No. Each type of extinguisher suits a different class of fire, and it has to be matched to the area being protected.
4. What kind of extinguisher should an electric bus use?
Separate an electrical equipment fire from thermal runaway in a lithium-ion battery. The choice should follow a risk assessment and the specific systems on that vehicle.
5. Can PAF-222 be used on a bus?
PAF-222 (FK-5-1-12) clean agent is worth considering for areas or equipment that suit the system, control cabinets or electronic equipment for instance, with the design following the actual space.
6. Can an automatic suppression system be fitted to a bus?
It can be considered for specific high risk areas: the engine bay, an equipment compartment, or the passenger cabin. The detection and suppression technology has to suit the vehicle and the risk.
7. How often should extinguishers on a bus be inspected?
According to the requirements of the relevant authority, the manufacturer, and the standards that apply to that equipment, so that they stay ready to use.
8. What should you do if a fire breaks out on a bus?
Stopping the vehicle, reporting the fire and evacuating the passengers come first. Only once the situation is safe, and if whoever is using it has been trained, should anyone consider using an extinguisher on a fire in its early stage.