fgd pump 400

The Four Common Types of Fire Pumps

The most common fire pump is the Horizontal Split Case.

Pros: Easiest to repair. We don’t need to touch the driver (motor, engine) to work on this pump. The pump has its own shaft and bearings making it a better machine. The horizontal split case can offer the widest range of pressures and flows. It can be driven by an electric motor or a diesel engine. The electric driven horizontal split case fire pump can be mounted both horizontal and vertical. These pumps can have multiple impellers (2 stage) for even higher pressures. These have been used in our industry for over 100 years.

Cons: Horizontal split case pumps take up floor space. Because the vast majority of the horizontal split case pumps are mounted to their drivers on the horizontal, they are long. These pumps need 10 pipe diameter distances of straight pipe on the suction side which uses even more space. They need positive suction pressure from the city water supply or a fire water tank at a higher elevation. A well-planned pump room can accommodate the needed space for these fire pumps and are the best choice for fire protection. We use these in all types of construction where there is room to facilitate their installation.

The second most common fire pump is the Vertical Inline.

We see these used in high density housing, small office buildings, and schools.

Pros: Because the motor is mounted to the top of the pump it requires much less space. It doesn’t need the 10 pipe diameter distances of straight pipe. Its self-vents trapped air.

Cons: Difficult to repair. Pump does not have its own shaft or bearings and uses the motor shaft and motor bearings as the impeller is mounted directly to motor. It has a limited pressure and flow range. Your probable going to need a larger horsepower motor to run an inline compared to a horizontal split case. Needs positive suction pressure from the city or a fire water tank at a higher elevation.

The third most common fire pump is the Vertical Turbine.

Pros: This is the only fire pump that can lift water from below grade. It can use an underground tank, pond, river, lake, well or ocean as its water source. It does not need a positive source of suction water pressure. It can be driven by an electric motor as well as a diesel engine. These have a wide pressure and flow range.

Cons: Highest cost out of the four and longest lead-time to obtain. Pump needs to be removed from pit with crane for repairs. Fewer trained repair techs available. We see these in areas where there is no municipal water supply or there is an existing body of water on site. Used in high rise bldgs. with tanks as backup to a city fed primary pump.

The fourth most common fire pump is the End-Suction.

Pros: Can be electric or diesel driven. Pump has its own shaft and bearings. Does not need 10 pipe dimeter distances of straight suction pipe. Discharge outlet is on the vertical and suction is on the horizontal and this configuration has some installation advantages.

Cons: Limited pressure and flows available. Even though we don’t need to mess with driver to repair the pump the pump will need to be disconnected from piping to be repaired. Needs positive suction pressure from the city or a fire water tank at a higher elevation.

Some differences between electric driven fire pumps and diesel driven fire pumps:

Electric fire pumps need a reliable source of power. Reliable source of power should have: No shut down of power lasting 4 continuous hours in prior year. No routine outages caused by failures in power generation or transmission. Disconnects and overcurrent must comply with code. AHJ has final determination. AHJ or Code may require transfer switch and generator backup. Almost all electric fire pumps need three phase power. There are jurisdictions that will not allow electric driven fire pumps because they deem the existing electrical utility as not a reliable source. Contra Costa County and the city of Tracy, CA are some examples. Diesel driven fire pumps are self-powered and are not affected by power outages when installed correctly. They can be less expensive than an electric driven fire pump when a transfer switch and generator are required. They do however require more pump room infrastructure. Diesel fuel tank adds some challenges as well as the needed exhaust fans, louvers, heater, muffler exhaust and batteries.