Before performing fireside cleaning in a boiler, what must be done with the steam smothering system?

Before performing fireside cleaning in a boiler, it is crucial to wire and tag the valves in the closed position for safety and operational integrity. This action ensures that no unintended steam or gas can flow through the system during the cleaning process. Properly securing the valves prevents the accidental release of steam, which could pose significant risks to personnel and the cleaning operation.

Wiring and tagging the valves indicate that maintenance is being performed and serves as a clear warning to other personnel that the system should not be operated. This practice is part of the Lockout/Tagout (LOTO) procedures that are essential for maintaining safety when working on potentially hazardous equipment. This approach fosters a safer work environment and helps to avoid accidents, making it the correct choice in this scenario.