A fire pump takes a water supply and increases its pressure (measured in psi or bar) to meet the demand of a sprinkler system, standpipe or foam system. They can be electric, diesel or steam driven and are used in buildings with high sprinkler demands like skyscrapers, storage warehouses, etc.
While fire pumps are commonly installed in commercial and industrial facilities, they are also used in emergency situations such as flooding or earthquakes. In many cases, the fire pump is the only source of water available for emergency operations.
Fire pumps are designed for the most demanding applications and operate under extreme conditions that require reliability, performance and endurance. They must be inspected, maintained and tested regularly to ensure they will work when needed most. A fire pump that fails to function under these demanding conditions can cause loss of life and property.
A fire pump is typically inspected, tested and maintained by a qualified person that has been trained to perform these tasks. Some of the inspections required for a fire pump are annual flow tests, weekly tests and monthly checks to ensure that they are functioning correctly. These tests are conducted to verify that the fire pump will provide adequate water flow and pressure when needed most. These tests can be performed by the fire department, a certified contractor or in-house staff.
Fire pump specifications vary, but they all have requirements for the design and installation of the system including a minimum pressure point, maximum flow rate, horsepower curves and the ability to resist cavitation. Fire pumps have low NPSH-curves to avoid cavitation which can reduce system pressure, and they have a stable and continuous decrease in Head [H] with decreasing Flow [Q].
The power sizing for the fire-pump driver is determined by a specific set of standards that are defined by each manufacturer. These specifications may require a constant rising power-curve or a peaking value in order to determine the appropriate size for the drive. It is important to look at the power-curve on the factory-certified test report to make sure it peaks and does not continue to rise after the peak. This will mean that the fire pump has not been properly sized for its application and could result in failure.
There are three types of drivers outlined in NFPA 20, Standard for Installation of Stationary Pumps for Fire Protection: electrical motor, diesel engine and steam turbine systems. Electrical motor drives are the most common, and they take electrical power from an approved power source that spins a shaft connected to the fire pump impeller. Diesel engines use the power generated by combustion of fuel to turn the impeller. Steam turbines are very rare and require a lot of infrastructure and expensive equipment to generate the necessary steam.
All of these different options for fire pump drives have specific requirements and limitations that should be considered by the Authority Having Jurisdiction. The AHJ is the entity that has final say on installations and can be the fire chief, the insurance company or another individual or group. fire pump