Backflow preventers must be listed for which service?

• A. Fire protection service.
• B. Domestic water supply.
• C. Irrigation service.
• D. Industrial process service.

Answer: (A)

Backflow preventers must be listed for the fire protection service because the sprinkler system is connected to the potable water supply and can experience pressure differences that could push sprinkler water back into that supply. A device that is specifically listed for fire protection service has been tested and approved to perform reliably in the conditions of a sprinkler system and to prevent backflow into the domestic supply. This listing ensures compatibility with fire protection piping and adherence to the required standards, so contamination of the potable water system is avoided. While backflow protection is important for other services too, the code here calls out listing for fire protection service to address the unique risks associated with sprinkler systems.