Selecting a Fire Pump Driver
The fire pump is a crucial component of many fire safety systems in commercial buildings. In many cases, it is installed to provide a boost in hydraulic pressure that allows fire sprinklers and standpipes to overcome gravity and flow water to the top of a high-rise building. This is not an insignificant task, and there are many considerations that must be made by the design engineer, fire protection professional and Local Authority Having Jurisdiction (AHJ) before any fire pumps are selected or installed.
When selecting a fire pump, the type of driver (electric motor, diesel engine or steam turbine) that will be used is of critical importance. Drivers are the motors that spin the impellers to generate the hydraulic pressure required for system operations. As such, they are an integral part of the overall system and must be properly sized for the requirements of the specific application.
There are several factors that should be considered when selecting a fire pump driver, including:
Generally speaking, electrical motor-driven fire pumps are the most popular due to their reliability, simplicity of operation and relatively low cost. They can be supplied from either the building’s power utility connection or a dedicated generator. The electric motor takes electrical power and converts it to mechanical energy that turns the shaft attached to the impeller, which in turn provides hydraulic water at high rates.
Diesel engine-driven fire pumps are also very reliable and offer a higher rated hydraulic pressure than electric motor-driven fire pumps. However, they are more complicated to operate, require a dedicated fuel source and may not be permitted by the Local Authority Having Jurisdiction.
Another factor to consider when choosing a fire pump driver is its horsepower rating. It is important to verify that the fire pump driver has been sized properly, and that it meets both UL and FM requirements. To accomplish this, look at the factory-certified test curve for the specific fire pump model and horsepower. Ensure that the curve peaks at or above the required duty point, and that it falls rapidly afterward.
It is also important to consider the trim of the fire pump when selecting a driver. In general, it is desirable to have a trim that maximizes the Q and H curves for maximum performance. However, these must be balanced against other criteria such as noise, vibration and the ability to meet local authority and fire code requirements for residual pressure.
Finally, it is important to note that fire pumps must undergo a full annual testing and inspection program by a licensed professional. During this process, the technician measures actual water flow and pressure to compare against the original fire pump design specifications. Any discrepancies must be explained and corrected in order to meet all applicable codes, standards and regulations.
Koorsen is committed to ensuring that our clients’ fire safety systems are tested, inspected and maintained properly. We only send specialized technicians to work on your fire pump, and they all receive training in our specialized fire pump lab before going out into the field. This helps ensure that your fire pump is always in working condition and able to perform its job when it matters most.