What is the maximum initiation delay for a vane type flow switch to alarm?

The correct choice in this question reflects the maximum initiation delay for a vane type flow switch to generate an alarm. A vane type flow switch is designed to detect the flow of water in a fire protection system, and it ensures that the alarm activates promptly when flow is detected. The maximum initiation delay of 90 seconds allows for a balance between system responsiveness and the possibility of transient conditions where minor fluctuations in water flow may not necessarily indicate a fire situation.

Setting the initiation delay at this duration helps to prevent false alarms that could result from temporary flow fluctuations, while still ensuring that an actual flow indicating a fire condition is promptly recognized and communicated to the alarm system. A more extended delay might result in delayed alarm response during an actual fire incident, which could compromise safety and readiness of the fire protection system.