The primary difference between hand portable fire extinguishers and wheeled fire extinguishers is the larger capacity of tank and the extinguishing agent it can carry. Hand portable fire extinguishers weigh up to 20 kg, and wheeled fire extinguishers can weigh over 800 pounds. Because of this primary difference of weight, engineers needed to design the fire extinguisher so that it could be transported and maneuvered by a single person. This mandated the need for wheels to be added to a frame which supported the tank so the person could transport it, by themselves, down corridors, around corners, and over rough terrain. In other words, it must allow the person to respond and act to extinguish the fire before it gets out of control and unable to be combatted by a fire extinguisher. However, optimally a second person would be available to help combat the fire with one person handling the unit movement duties and activating the fire extinguisher, and the other person handling the hose and horn to direct the flow of the agent.
In addition, the fire extinguisher would need to be engineered so that it could be stored, recharged, and serviced differently than a hand portable extinguisher.
The Primary Parts of a Wheeled Fire Extinguisher
- Pneumatic Tires: The pneumatic wheels are designed to be move effective in moving the fire extinguisher unit when the surface that you will traverse is soft or softer than a hard surface. Pneumatic tires are often found on wheeled fire extinguishers that weight less than 400 pounds (181 kg).
- Large Steel Wheels: The large wheels, up to 36” x 6”, enhance leverage and mechanical advantage allowing the user, often as single user, to more easily and quickly transport the very heavy load. Most wheeled fire extinguishers that weigh over 400 pounds (181 kg) have steel wheels.
- Large Steel Wheels with Rubber Tread: Rubber coated, or rubber tread applied wheels are desirable on units that are used in areas where special flooring such as vinyl, tile, or wood could be damaged by the metal wheels. Also, the rubber tread eliminates the metal to floor contact that could produce a spark and, if in a volatile area, start a fire.
- Frame: The frame supports the cylindrical tank and the axel to it so that the wheels will be assembled for heavy duty support and stability.
- Cylinder Tank: Wheeled fire extinguisher tanks are large and can carry hundreds of pounds of extinguishing agent. They are similar in look to the flat bottom and dome shaped top of hand portable extinguishers, only significantly larger.
- Nitrogen Cylinder with Turn Valve: This tank houses the nitrogen or propellent that is used to pressurize and expel the extinguishing agent from the extinguisher tank. The turn valve atop the cylinder opens and closes to release the nitrogen into the extinguisher cylinder tank.
- Special Cylinder and Frame Treatment: Because most wheeled fire extinguishers are stationed outdoors, and often in a marine setting, the cylinders and frames have a galvanizing compound undercoat, a baked-on enamel top coat, and a protective clear coat finishing to help protect against corrosion and fading from expose to sun, sea water, and salt.
- Hose with Nozzle Assembly: the nozzle has a bale or handle assembly that allows the user to adjust the flow rate of the extinguishing agent and nitrogen propellent by moving it backward to release the agent and pushing it forward to reduce and turn off the flow of agent.
- Extinguishing Agent: The substance that limits or suppresses the spread of the fire. An understanding of the different classifications (Classes) of fires is helpful in determining which type of fire extinguisher is best for your situation. Below is a helpful chart explaining the different Classes of Fires and their unique characteristics such as their typical fuel source, the setting in which a type of fire usually occurs, and the most effective type of fire extinguisher to use in combating the fire. The second chart provides a breakdown of the various types of fire extinguishers, the firefighting agents used, their advantages/uses and disadvantages.