What is the rated capacity of the fire pump in gallons per minute and its discharge pressure?

• A. 1,200 gpm at 120 psig
• B. 1,500 gpm at 150 psig
• C. 1,100 gpm at 140 psig
• D. 1,000 gpm at 150 psig

Answer: (D)

Fire pump rating is defined by how much water it can deliver at a specific discharge pressure. This pairing—flow in gallons per minute with the discharge pressure in psig—directly determines how well the fire main can be fed through the piping to distant points and nozzles, overcoming friction losses along the way. The standard rating for this system is 1,000 gpm at 150 psig, which provides enough volume to supply multiple hose streams while maintaining a nozzle pressure that crews rely on during firefighting. Pushing for more flow, such as 1,200 or 1,500 gpm, would require a larger, more powerful pump and more energy; reducing the discharge pressure to 120 or 140 psig would lower the pressure delivered to farthest outlets, potentially compromising firefighting effectiveness. Therefore, 1,000 gpm at 150 psig best matches the required performance and practical pump sizing for the fire main.