By Roger Lackore

So many times in life we are forced to pick the “least of all evils.” So, it is nice when we at the Fire Apparatus Manufacturers’ Association (FAMA) can discuss a topic where you can choose the best from a list of “all goods.” This is the case when it comes to selecting an auxiliary braking system for your next fire apparatus.

National Fire Protection Association (NFPA) 1901, Standard for Automotive Fire Apparatus, requires that any apparatus with a greater than 33,000-pound gross vehicle weight rating (GVWR) must be equipped with an auxiliary braking system. This means a system that assists in stopping the apparatus above and beyond the action of the service brakes located at the wheel ends. Auxiliary braking can be accomplished through the action of the engine, the transmission, or other means acting on the apparatus drivetrain.

Overview

Modern fire apparatus, like every other heavy on-road vehicle, are equipped with a service braking system that uses friction to slow the vehicle. This friction comes from physical contact between a consumable material (brake pads or shoes) and a mechanical device (brake drums or rotors). The contact force is created by either hydraulic force (smaller vehicles) or compressed air (heavy vehicles). The air pressure in heavy vehicles is produced by a compressor driven by the engine.

The downside of friction braking systems is that they create heat that must be dissipated. The heavier the vehicle and the faster the stop, the more heat is created. In heavy braking situations, this heat can cause the brakes to fade or lose their braking power. This can occur if the brakes are used frequently or consistently down long grades. In extreme braking situations, the components can get hot enough to damage the brakes.

Auxiliary braking systems supplement the service brakes, increasing the stopping power and reducing the likelihood that the service brakes will overheat. The NFPA Apparatus Committee felt strongly that this capability was important in fire apparatus, which are more likely to brake hard and brake frequently. This is the reason it began requiring auxiliary braking systems on large fire apparatus. In addition to these safety benefits, appropriate use of an auxiliary braking system will extend the life of the service brakes, reducing cost and frequency of maintenance.

Common Systems

Commercially available auxiliary braking systems all use some method other than mechanical friction to help slow a vehicle. They also all work by creating a braking force on the vehicle driveline, which in turn transfers force to the tires and then to the road. They all generate heat, but they all control the dissipation of that heat. There are four categories of auxiliary braking systems currently available on fire apparatus:

• Electromagnetic retarders.
• Exhaust brakes.
• Engine compression brakes.
• Transmission retarders.

Electromagnetic Retarders

Electromagnetic retarders create their stopping power using the force that can be generated by a magnetic field. You can experience this force if you bring the north or south poles of two magnets together. In vehicle applications, the magnetic fields are created by electricity flowing through a set of coils. The initial electric power to generate the field comes from the vehicle batteries and i

By Roger Lackore

So many times in life we are forced to pick the “least of all evils.” So, it is nice when we at the Fire Apparatus Manufacturers’ Association (FAMA) can discuss a topic where you can choose the best from a list of “all goods.” This is the case when it comes to selecting an auxiliary braking system for your next fire apparatus.

National Fire Protection Association (NFPA) 1901, Standard for Automotive Fire Apparatus, requires that any apparatus with a greater than 33,000-pound gross vehicle weight rating (GVWR) must be equipped with an auxiliary braking system. This means a system that assists in stopping the apparatus above and beyond the action of the service brakes located at the wheel ends. Auxiliary braking can be accomplished through the action of the engine, the transmission, or other means acting on the apparatus drivetrain.

Overview

Modern fire apparatus, like every other heavy on-road vehicle, are equipped with a service braking system that uses friction to slow the vehicle. This friction comes from physical contact between a consumable material (brake pads or shoes) and a mechanical device (brake drums or rotors). The contact force is created by either hydraulic force (smaller vehicles) or compressed air (heavy vehicles). The air pressure in heavy vehicles is produced by a compressor driven by the engine.

The downside of friction braking systems is that they create heat that must be dissipated. The heavier the vehicle and the faster the stop, the more heat is created. In heavy braking situations, this heat can cause the brakes to fade or lose their braking power. This can occur if the brakes are used frequently or consistently down long grades. In extreme braking situations, the components can get hot enough to damage the brakes.

Auxiliary braking systems supplement the service brakes, increasing the stopping power and reducing the likelihood that the service brakes will overheat. The NFPA Apparatus Committee felt strongly that this capability was important in fire apparatus, which are more likely to brake hard and brake frequently. This is the reason it began requiring auxiliary braking systems on large fire apparatus. In addition to these safety benefits, appropriate use of an auxiliary braking system will extend the life of the service brakes, reducing cost and frequency of maintenance.

Common Systems

Commercially available auxiliary braking systems all use some method other than mechanical friction to help slow a vehicle. They also all work by creating a braking force on the vehicle driveline, which in turn transfers force to the tires and then to the road. They all generate heat, but they all control the dissipation of that heat. There are four categories of auxiliary braking systems currently available on fire apparatus:

• Electromagnetic retarders.
• Exhaust brakes.
• Engine compression brakes.
• Transmission retarders.

Electromagnetic Retarders

Electromagnetic retarders create their stopping power using the force that can be generated by a magnetic field. You can experience this force if you bring the north or south poles of two magnets together. In vehicle applications, the magnetic fields are created by electricity flowing through a set of coils. The initial electric power to generate the field comes from the vehicle batteries and i

By Roger Lackore

So many times in life we are forced to pick the “least of all evils.” So, it is nice when we at the Fire Apparatus Manufacturers’ Association (FAMA) can discuss a topic where you can choose the best from a list of “all goods.” This is the case when it comes to selecting an auxiliary braking system for your next fire apparatus.

National Fire Protection Association (NFPA) 1901, Standard for Automotive Fire Apparatus, requires that any apparatus with a greater than 33,000-pound gross vehicle weight rating (GVWR) must be equipped with an auxiliary braking system. This means a system that assists in stopping the apparatus above and beyond the action of the service brakes located at the wheel ends. Auxiliary braking can be accomplished through the action of the engine, the transmission, or other means acting on the apparatus drivetrain.

Overview

Modern fire apparatus, like every other heavy on-road vehicle, are equipped with a service braking system that uses friction to slow the vehicle. This friction comes from physical contact between a consumable material (brake pads or shoes) and a mechanical device (brake drums or rotors). The contact force is created by either hydraulic force (smaller vehicles) or compressed air (heavy vehicles). The air pressure in heavy vehicles is produced by a compressor driven by the engine.

The downside of friction braking systems is that they create heat that must be dissipated. The heavier the vehicle and the faster the stop, the more heat is created. In heavy braking situations, this heat can cause the brakes to fade or lose their braking power. This can occur if the brakes are used frequently or consistently down long grades. In extreme braking situations, the components can get hot enough to damage the brakes.

Auxiliary braking systems supplement the service brakes, increasing the stopping power and reducing the likelihood that the service brakes will overheat. The NFPA Apparatus Committee felt strongly that this capability was important in fire apparatus, which are more likely to brake hard and brake frequently. This is the reason it began requiring auxiliary braking systems on large fire apparatus. In addition to these safety benefits, appropriate use of an auxiliary braking system will extend the life of the service brakes, reducing cost and frequency of maintenance.

Common Systems

Commercially available auxiliary braking systems all use some method other than mechanical friction to help slow a vehicle. They also all work by creating a braking force on the vehicle driveline, which in turn transfers force to the tires and then to the road. They all generate heat, but they all control the dissipation of that heat. There are four categories of auxiliary braking systems currently available on fire apparatus:

• Electromagnetic retarders.
• Exhaust brakes.
• Engine compression brakes.
• Transmission retarders.

Electromagnetic Retarders

Electromagnetic retarders create their stopping power using the force that can be generated by a magnetic field. You can experience this force if you bring the north or south poles of two magnets together. In vehicle applications, the magnetic fields are created by electricity flowing through a set of coils. The initial electric power to generate the field comes from the vehicle batteries and i

By Alan M. Petrillo

1 Summit Fire Apparatus built this quick-attack truck for the Western Holmes (OH) Fire Department on a Ford F-550 chassis. (Photos 1 and 2 courtesy of Summit Fire Apparatus.)

They go by different names - fast-attack units, mini pumpers, quick-attack pumpers - but they share similar features and missions.

Typically, these vehicles have short wheelbases; have gross vehicle weight ratings (GVWR) under 20,000 pounds; carry a modest-sized pump, around 300 gallons of water, and perhaps some foam; and are charged with fire knockdown duties and sometimes even rescue operations.

Mini and Midi Pumpers

2 The Jacksonville (MD) Fire Department went to Summit Fire Apparatus for this fast-attack/brush truck built on a Ford F-550 chassis and adapted to Super Single tires and rims.

Joe Messmer, president of Summit Fire Apparatus, says that departments coming to Summit say they want smaller pumpers with the ability to get into and out of areas where larger vehicles might have trouble. “They want vehicles that are able to get in quicker, and their firefighters often don’t want to drive large trucks,” Messmer says. “They tell us they want a vehicle that’s more agile and able to get around better in tighter areas.”

Summit recently built a quick-attack mini pumper for the Reedy (WV) Fire Department, Messmer notes, on a Ford F-550 4x4 chassis with a Powerstroke 6.7-liter V8 turbo diesel engine, seating for six firefighters, a Waterous 1,250-gallon-per-minute (gpm) power takeoff (PTO) pump, and a 300-gallon polypropylene water tank with an integral 30-gallon foam tank. Summit also built a mini pumper for the South New Berlin (OH) Fire Department on a Ford F-550 that seats six firefighters and carries a Hale 1,000-gpm pump and a 250-gallon water tank. Both rigs have Robinson roll-up doors and a transverse compartment behind the crew cab.

3 Midwest Fire Equipment built this fast-attack pumper for the Whiteford Township (MI) Fire Department on a Ford F-550 crew cab chassis with Super Single rims and tires and a four-inch lift kit. (Photos 3 and 4 courtesy of Midwest Fire Equipment.)

As a slight step up from the typical mini pumper, Messmer says Summit built a “midi pumper” for the Clinton Warren (OH) Fire Department on a GM 5500 four-door chassis with an emergency medical services (EMS) compartment in the crew cab. The rig has a Hale 1,000-gpm midship pump, a 300-gallon UPF Poly water tank, a Hale 2.1A FoamLogix foam system, al