During an acceptance test, which method can be utilized for testing a sprinkler waterflow switch according to NFPA 72?

The method of opening the inspector's test valve to cause actual water flow is the correct approach for testing a sprinkler waterflow switch according to NFPA 72. This method directly simulates real-world conditions by allowing water to flow through the fire protection system, which in turn activates the waterflow switch. This activation is essential to verify that the switch is functioning correctly and will signal the fire alarm system as intended in an actual fire event.

In practical terms, using this method offers definitive verification that the switch responds appropriately to an influx of water, ensuring that it will alert the alarm system when needed. This hands-on testing is crucial to confirm proper integration and operation within the overall fire protection system.

Other methods, such as using a pressure gauge, checking the battery backup, or testing with a multimeter, do not provide the same level of assurance regarding the waterflow switch's operational readiness. These alternative tests might assess other aspects of the system but do not replicate the actual conditions that the switch will encounter in an emergency situation, which is why they are not suitable for acceptance testing of the waterflow switch.