What is the maximum delay allowed for a waterflow switch in a typical fire alarm system?

What is the maximum delay allowed for a waterflow switch in a typical fire alarm system?

• A. 60 sec
• B. 90 sec
• C. 120 sec
• D. 180 sec

Answer: (B)

Waterflow switches alert the fire alarm system as soon as water starts moving in the sprinkler piping. There’s a need to balance prompt notification with avoiding false alarms from minor, non-fire flows. In a typical system, the alarm must be initiated within about 90 seconds of detecting water flow. This keeps occupants and responders informed quickly, while not overreacting to small, incidental flows. A shorter delay, like 60 seconds, could raise nuisance alarms in some situations, whereas longer delays (120 or 180 seconds) would delay warning and could allow more water damage before the alarm sounds.

Waterflow switches alert the fire alarm system as soon as water starts moving in the sprinkler piping. There’s a need to balance prompt notification with avoiding false alarms from minor, non-fire flows. In a typical system, the alarm must be initiated within about 90 seconds of detecting water flow. This keeps occupants and responders informed quickly, while not overreacting to small, incidental flows. A shorter delay, like 60 seconds, could raise nuisance alarms in some situations, whereas longer delays (120 or 180 seconds) would delay warning and could allow more water damage before the alarm sounds.