Which option correctly states the service for which backflow preventers must be listed?

• A. They must be listed for irrigation service.
• B. They must be listed for domestic water service.
• C. They must be listed for fire protection service.
• D. They must be listed for industrial process service.

Answer: (C)

Backflow preventers tied to sprinkler systems must be listed for the service they protect, so they’re proven suitable for that specific use. For residential sprinkler systems, the service is fire protection. Listing for fire protection service ensures the device is tested to handle the pressures, flow demands, and potential backflow scenarios that can occur in a fire sprinkler system, and that it won’t contaminate the potable water supply. Listing for irrigation, domestic water, or industrial process services would apply only if those were the actual use, not for a fire protection system. So the correct requirement is listing for fire protection service.