Fire pumps are essential parts of a building’s sprinkler system, providing high water flow and pressure when needed to quickly suppress fires. They can pump up to 5,000 gallons per minute and produce as much as 600 PSI of water pressure, depending on the application. Despite their relatively infrequent use, the systems must operate reliably and be ready to go at a moment’s notice. As such, the pumps need to be designed and built with both rate-of-flow and water pressure requirements in mind. They are also subject to stringent testing and maintenance protocols that differ from electric fire pumps.
Like any engine, diesel fire pump require routine inspection and maintenance to keep them functioning at peak performance. The fuel tank needs to be inspected and filled on a regular basis, and the oil and air filters need to be changed. This maintenance is very similar to the routine services you perform on your car, and failing to do it can significantly reduce a fire pump’s lifespan.
While the maintenance of a diesel fire pump is relatively simple, it’s important to understand how these systems are powered. NFPA 20 standards typically call for a dedicated generator to provide the emergency power required for an operation. Unfortunately, the power requirements of the fire pump can be significantly higher than that of a typical electrical motor. This means the generator may need to be sized more than twice as large to be able to handle the full load requirement of the fire pump.
Similarly, the exhaust system for a fire pump must be properly sized and insulated to ensure it can safely meet the demands of the engine. The piping should be kept short and insulated to minimize heat transfer, and the exhaust system should also be protected with a fireproof wall or ducting. Lastly, the exhaust system should be rated to withstand the maximum temperature that will be experienced during the system’s operation, as specified by NFPA 20 and the engine manufacturer.
The NFPA 20 standard for diesel fire pump engines requires that the engine be located in an environment that can maintain a temperature of no more than 120 F while the pump is running under full load. This is to protect the engine from excessive heat, which can cause a number of problems, including degradation of the internal components. Fortunately, there are thermostatically controlled heaters available that can be used to maintain the engine at this operating temperature.
It is also important to keep the fire pump’s diesel engine fueled with diesel fuel that meets NFPA standards. The fuel tank must be sized to accommodate the engine, and it should be a closed-loop system with a dedicated service that complies with the engine’s requirements. Ideally, this will prevent fuel contamination and provide the best possible performance.
There are only three ways a fire pump can be shut down: if it runs out of fuel, if the selector switch inside the controller is placed in the off position, or if an emergency power shutdown occurs. In most cases, these events will occur in the middle of an emergency, so it is important to have a plan in place to make sure the fire pump is fully prepared and ready to go.