What is the purpose of lockout/tagout in preventing injuries?

• A. To ensure energy sources are isolated and cannot be re-energized during maintenance or repair.
• B. To schedule downtime for maintenance.
• C. To monitor vibration.
• D. To seal electrical enclosures.

Answer: (A)

Lockout/tagout is about controlling hazardous energy to protect workers during maintenance. By isolating all energy sources—electrical, hydraulic, pneumatic, spring, gravity, etc.—and applying a lock or tag to the energy-control devices, the equipment is prevented from being re-energized while work is being done. The lock physically blocks the switch or valve from being turned on, and the tag warns that the machine is under maintenance and should not be activated. This approach also often includes verifying that the energy is truly off before work begins, so there’s no surprise startup or energy release.

The other options don’t address preventing unexpected energization during maintenance. Scheduling downtime is about planning, not controlling energy. Monitoring vibration is a condition-check activity, not a safety control to stop machines from energizing. Sealing electrical enclosures protects against environmental exposure, not worker safety during servicing.