What is the maximum time a vane type flow switch can take to initiate an alarm?

A vane type flow switch is designed to detect the flow of water within a fire protection system, such as a sprinkler system. The standards for these devices typically specify a maximum time limit for the switch to respond to water flow in order to ensure that an alarm is promptly initiated when a fire is detected.

In the case of a vane type flow switch, a maximum response time of 90 seconds is established to ensure that there is minimal delay in notifying occupants and emergency response teams. This is crucial for life safety and fire suppression efforts, as any delay in alarm activation could result in increased risk to life and property damage.

This timing allows for the necessary coordination between detecting flow and activating alarms while accommodating the typical delays that may occur due to the physical characteristics of water movement and the mechanical operation of the switch itself. Therefore, 90 seconds is the maximum allowable time for a vane type flow switch to initiate an alarm, ensuring a balance between timely response and the operational characteristics of the switch.