What is lockout?

• A. Isolates energy sources and prevents re-energizing during maintenance
• B. Labels equipment to indicate maintenance is in progress
• C. A job briefing
• D. Verbal authorization

Answer: (A)

Lockout is a safety procedure used when maintenance or repairs are performed to ensure the equipment can’t start up or release stored energy while someone is working on it. It involves isolating all energy sources—electrical, hydraulic, pneumatic, mechanical, etc.—and applying a locking device to the energy-isolating component so it cannot be re-energized. This physical lock, operated by the authorized worker, ensures a zero-energy state before work begins and is removed only after the area is clear and all work is complete. This is why it’s the best description: it directly describes both isolating energy sources and preventing re-energizing during maintenance. Labels, briefings, or verbal authorization don’t provide that physical protection.