My hi level interlock just tripped on my vessel – can I count this trip as the scheduled quarterly/annual PM test? This question is maybe in the top 10 questions we get from PSM/RMP clients and friends and without a doubt one of the top 5 MI questions of all time. There is no argument to the logic that we just tested our safety system and it worked; but from a process safety engineering aspect there are many issues with taking this simplified approach to such a critical element of process safety. In this article I will explain how we should NOT be counting this activation as a scheduled PM, but also the other activities that MUST TAKE PLACE to ensure process safety, as well as compliance with PSM/RMP when a safety system is activated.