On projects that are large or complex (e.g., a paper mill, new factory, power plant, etc.), the transition from “under construction” to “fully operational” may take months. During construction, it’s common to operate equipment and systems. But once the construction firm commences turnover of the equipment and systems to the owner, you can’t just go operating things anymore.
Maybe last month you cycled the fill valves on a mixing tank as part of a loop check. But this month, the system is now under the plant operators and there is acid in the day tank.
Once operators are onsite, they may be conducting their own tests (e.g., functional testing) or training (operating equipment to simulate plant processes). Don’t operate any controls for which you did not specifically obtain authorization that day. Yesterday’s authorization might not be good today. Get the authorization from the operations supervisor before commencing that day’s work.