Fire pumps can be powered by an electric motor or a diesel engine driven pump. The latter is often specified to require backup power, and it is important that the system be designed to properly handle the backup power requirements.

This article will discuss the basics of diesel fire pumps and some of the considerations to be made when designing the system for backup power.

NFPA 20 and the associated codes and standards provide various options for the designer to choose how to configure the primary and emergency power supply systems to ensure that the fire pumps have the proper power available for operation. The most obvious issue is determining how to size the standby generator to handle the starting inrush current and all the emergency loads at the same time while meeting the voltage drop allowed during these conditions at the fire pump motor.

Another key issue is how to ensure that the fire pump can be halted in an emergency. This is accomplished through the use of a selector switch located inside of the controller, which will allow the fire department or emergency responders to shut off the pump. There are some conditions, such as low fuel pressure or high engine temperature, which will not halt the pump from operating and should be considered in the design of the system.

Finally, the installation of a diesel engine-driven fire pump can be complicated by the requirements related to refueling the tank and the ventilation of combustion exhaust. It is also critical that the system be inspected and tested on a yearly basis to ensure that the pump has the capabilities to operate in an emergency situation. diesel driven fire pump