What is backflow prevention and why is it important in fire protection?

• A. Protect potable water from siphoning contaminants back into the supply.
• B. Prevent fire sprinkler water from freezing.
• C. Increase water pressure in the fire system.
• D. Reduce chlorine residual in the water.

Answer: (A)

Backflow prevention means keeping water moving only from the supply to the building, and never back into the potable water system when pressure conditions change. It's important because pipes in a fire protection system can connect to the same water supply, and without backflow protection a drop in pressure or a pressure difference could pull contaminated water back into the drinking-water supply. In fire protection, preventing backflow protects public health and prevents cross-connections from letting firefighting water—potentially containing debris or residues—into the potable supply. Devices like check valves and backflow preventers are installed at cross-connections to stop reverse flow and maintain water quality. This description—protecting potable water from siphoning contaminants back into the supply—best captures the purpose of backflow prevention. The other options relate to freezing, pressure changes, or residual chlorine, which aren’t the aims of backflow prevention.