In lockout-tagout procedures, which element serves to physically prevent energy release?

• A. A tag that indicates equipment is hazardous.
• B. A procedure checklist.
• C. A lockout device that physically secures energy isolation.
• D. A warning sign lit in the control room.

Answer: (C)

The element that physically prevents energy release is the lockout device that actually secures the energy isolation point. By attaching a lock (such as a padlock or similar device) to the switch, valve, or circuit breaker, the energy source is held in the safe position and can’t be re-energized until the lock is removed by the authorized person. The lock provides a tangible barrier that stops operation, which is essential for real protection during maintenance.

A tag simply communicates that a hazard exists and who applied the lockout; it does not stop energy from being released. A procedure checklist guides actions but doesn’t physically block energy. A warning sign in the control room is informational and does not prevent re-energizing.