What is the purpose of a surge/relief valve in a fire pump discharge line?

What is the purpose of a surge/relief valve in a fire pump discharge line?

• A. To speed up discharge
• B. To seal the line
• C. To protect downstream piping from overpressure due to pump operation or line restrictions
• D. To measure flow rate

Answer: (C)

Surge/relief valves are used to prevent overpressure in the fire pump discharge line when the pump starts, stops, or when flow changes abruptly downstream. If pressure in the discharge line rises above a set limit due to the pump’s operation or downstream line restrictions, the valve opens to vent the excess pressure. This protects downstream piping, valves, and equipment from damage caused by hydraulic surges or sudden closures. It’s not about speeding up discharge, sealing the line, or measuring flow rate—those aren’t functions of a relief valve.

Surge/relief valves are used to prevent overpressure in the fire pump discharge line when the pump starts, stops, or when flow changes abruptly downstream. If pressure in the discharge line rises above a set limit due to the pump’s operation or downstream line restrictions, the valve opens to vent the excess pressure. This protects downstream piping, valves, and equipment from damage caused by hydraulic surges or sudden closures. It’s not about speeding up discharge, sealing the line, or measuring flow rate—those aren’t functions of a relief valve.