What is the purpose of lockout/tagout procedures?

• A. To energize machines so they can run during maintenance
• B. To label machines after maintenance but not affect operation
• C. To unlock safety interlocks during normal operation
• D. To ensure machines are de-energized and cannot start during maintenance

Answer: (D)

Lockout/tagout is about controlling hazardous energy so a machine cannot start or release stored energy while someone is working on it. The goal is to make sure the equipment is fully shut off, isolated from all energy sources, and cannot be re-energized until the maintenance is finished and it’s safe to operate again. Practically, this means shutting down the machine, isolating energy sources, applying a lock (which physically prevents re-energizing) and/or a tag (which warns and identifies who is working), and confirming there is zero energy before starting work. Only the person who applied the lock or tag should remove it, after the area is safe. This is the best fit because it directly prevents unexpected startup and protects workers from stored-energy releases. The other ideas miss that protective control: powering the machine during maintenance is dangerous, labeling alone doesn’t stop operation, and unlocking safety interlocks defeats the purpose of preventing starts during service.