The water flow alarm on a fire protection system combined with a building's heating and air conditioning system must respond to discharge through the system's test pipes under what condition?

The water flow alarm on a fire protection system combined with a building's heating and air conditioning system must respond to discharge through the system's test pipes under what condition?

• A. When the water flow exceeds the discharge from the largest K-factor sprinkler
• B. When the water flow is less than that from a signal automatic sprinkler of the smallest K factor installed on the system
• C. When water flow equals the average flow of all sprinklers
• D. When water flow drops below 1 gpm

Answer: (B)

When a water flow alarm is tied to the inspector’s test pipe, it needs to react to the small amount of water that is intentionally discharged during testing, not to the larger flows that can come from a sprinkler turning on. The flow from a single sprinkler is governed by its K factor, and the smallest K-factor sprinkler sets the minimum expected discharge for any one sprinkler. The test-pipe flow is deliberately kept below that minimum sprinkler discharge so that the alarm instantly detects the test flow without being overwhelmed or confused by normal or larger sprinkler discharges. That's why the correct condition is that the water flow in the test pipes is less than the discharge from the signal automatic sprinkler with the smallest K factor installed on the system.

When a water flow alarm is tied to the inspector’s test pipe, it needs to react to the small amount of water that is intentionally discharged during testing, not to the larger flows that can come from a sprinkler turning on. The flow from a single sprinkler is governed by its K factor, and the smallest K-factor sprinkler sets the minimum expected discharge for any one sprinkler. The test-pipe flow is deliberately kept below that minimum sprinkler discharge so that the alarm instantly detects the test flow without being overwhelmed or confused by normal or larger sprinkler discharges. That's why the correct condition is that the water flow in the test pipes is less than the discharge from the signal automatic sprinkler with the smallest K factor installed on the system.