How Fire Engines Work

A brief article about how fire engines work and the different types of trucks.

Fire engines have come a long way from the bucket brigades of the past. Bucket brigades were limited by how far the water could be tossed into the fire. Early fire engines were created to lengthen the distance that water was sprayed. These engines could spray water farther and more accurately but they still had no way of bringing water up the hose. So the bucket brigade continued by constantly refilling the water tub on the engine.

Today's fire engines and trucks are very specialized pieces of fire suppression tools. Engines typically carry three firefighters, a Captain, an Engineer and a Firefighter. Sometimes a second firefighter is added for extra safety. Fire engines carry many tools such as ladders, axes and spare equipment for firefighters.

Fire engines and trucks are large vehicles and are usually red or yellow. A fire engine is a vehicle that carries its own water supply. This water supply is replenished by a fire hydrant, a water tender or any available water source like a swimming pool. Therefore, these engines are also called pumpers since they pump the water onto the fire. They can pump water at a rate of around 2000 gallons per minute and at 300 pounds of pressure. Looking on the side of a pumper-type engine you will see hydrant connection tools and connections for the water hoses. The big connector on the bottom is where water goes into the pump and the smaller connections are where the water goes into the hoses.



A fire truck does not have an onboard water supply. Instead, it carries long ladders, heavy rescue tools and hydraulic platforms. These trucks work as support for the engines. A hook-and-ladder fire truck is the most common form. Also called 'aerial ladders', they typically carry only one firefighter or operator. The extra ladders that these trucks carry can reach as high as 120 feet or around 10 stories.

There is a third type of fire engine called a quint. This truck is a mix of the two other types. It carries its own water source, elevating ladders and other emergency equipment. They are used in areas with low staffing or on the East Coast usually.

There are usually two types of pumps used for the water. A positive displacement pump is one pump type, which self primes and has high pressure. However, there are a lot of moving parts and can break down. The other pump type is a centrifugal pump. These pumps have fewer moving parts and can move large volumes of water. They can break down and no longer build pressure and need a small positive displacement to prime the pump.

The control panel on a fire engine usually has three sections. The superior section is where the feeding switches and panel illumination are located. The intermediate section contains pressure gauges of the various pumps. The inferior section contains valves for recirculation, spill, suction and other uses.

Other types of fire trucks are all about rescue and supporting the firefighters. There are rescue trucks, tanker trucks, HazMat trucks and crash trucks. At a fire, each type of truck is parked in the same areas so firefighters will always know where the equipment is that they might need.

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