What is the function of a check valve in hydrant/standpipe systems?

What is the function of a check valve in hydrant/standpipe systems?

• A. To release trapped air.
• B. To prevent reverse flow and maintain proper pressure within the protected piping.
• C. To monitor water quality.
• D. To regulate chemical injection.

Answer: (B)

A check valve in hydrant/standpipe systems is a one-way valve that prevents reverse flow and helps keep the water in the protected piping at the intended pressure. When water is flowing toward hydrants or standpipes, the valve opens and allows the discharge. If pressure on the downstream side tries to push water back toward the supply, the valve closes automatically, blocking backflow. This keeps the firefighting lines pressurized and protects the supply from contamination from cross-connections or backflow conditions, especially when pumps or multiple outlets are involved. Air release valves, water quality monitoring, and chemical injection are separate functions handled by other devices, not by a check valve.

A check valve in hydrant/standpipe systems is a one-way valve that prevents reverse flow and helps keep the water in the protected piping at the intended pressure. When water is flowing toward hydrants or standpipes, the valve opens and allows the discharge. If pressure on the downstream side tries to push water back toward the supply, the valve closes automatically, blocking backflow. This keeps the firefighting lines pressurized and protects the supply from contamination from cross-connections or backflow conditions, especially when pumps or multiple outlets are involved. Air release valves, water quality monitoring, and chemical injection are separate functions handled by other devices, not by a check valve.