How to Size a Fire Water Pump

The fire water pump is the heart of your fire protection system. It is responsible for delivering enough pressure and flow to the sprinklers and appliances to properly extinguish fires and protect the lives of firefighters.

When sizing your fire water pump it is important to know what your demands will be and how much water you will need to push through the system. There are many factors that can affect your flow and pressure including, building height, occupancy classification and fire hazards within the structure. You also need to understand the different operating principles, driver options and applications of fire pumps.

A good starting point is to understand what the manufacturer rated capacity of the pump is. This number is usually listed as either gallons per minute (GPM) or gallons per hour. This value gives you the ability to see the maximum amount of flow it is capable of producing at a specific pressure. The rated capacity is used as the base of your fire water pump design.

The nozzleman needs to know the fire water pump’s rated capacity and flow so they can determine if it is capable of providing enough pressure at the nozzle to successfully fight a fire. The nozzleman must consider friction loss in the system as well. Friction loss happens every time water changes direction through a hoseline or appliance. The Denver Fire Department has set values for each appliance and the fire pump operator must take these into account to ensure proper nozzle operation.   fire water pump