A diesel engine driven fire pump is a pump that has an internal diesel engine to drive it. Unlike electric fire pumps, which have an emergency generator to provide their power source, a fire water pump driven by a diesel engine can continue to operate even if the electrical power is cut during a fire.
This type of fire pump is very reliable and comes in a variety of rated flow capacities, pressures, and discharge heads. They can be used with either an electric or a diesel driver and are easy to maintain due to the relatively simple split-case design that allows access to all of the critical components. However, like all fire pumps, they must be tested and inspected on a yearly basis to ensure that they will operate properly during a fire.
One of the most common causes of damage to stand-by diesel engine fire pumps during an annual test is due to improper water flow to the engine heat exchanger from the fire line piping. Without a sufficient flow of water, the engine heat exchanger will overheat and potentially cause damage to the cylinder heads or pistons.
The piping from the exhaust system to the engine must be properly sized using a pipe sizing calculator to ensure that it meets the required back pressure of the engine and that it conforms to UL and FM listings. Additionally, the lubrication system needs to be charged and a leak test performed on all of the critical lubrication systems.