According to NFPA 72, what is the maximum time water can flow before the flow switch goes into alarm?

In accordance with NFPA 72, which provides the standard for the installation, maintenance, and use of fire alarm systems, the maximum time that water can flow before the flow switch goes into alarm is indeed set at 90 seconds. This requirement is crucial because it ensures that the fire alarm system can promptly respond to the activation of the sprinkler system, minimizing potential water damage and ensuring timely notification for evacuation and firefighting efforts.

The 90-second timeframe is designed to balance the need for immediate response without generating false alarms, as it allows for momentary fluctuations that can occur during normal operation of the sprinkler system. This specification helps to maintain the effectiveness of the fire protection system while ensuring that alarm events are accurately communicated to building occupants and emergency services.