Lockout/Tagout (LOTO) controls hazardous energy — electrical, pneumatic, hydraulic, or stored gravity — before anyone services equipment. Executed correctly, it prevents unexpected energization and saves lives.

Governing Standard

• OSHA 29 CFR 1910.147 — The Control of Hazardous Energy (Lockout/Tagout)
• Applies to servicing and maintenance of machines where unexpected startup could injure workers
• NFPA 70E Article 120 covers establishing an electrically safe work condition

The LOTO Sequence

• 1. Notify — inform all affected employees that equipment will be shut down
• 2. Identify — locate every energy source: electrical, pneumatic, hydraulic, stored gravity
• 3. Shut down — use the normal stopping procedure to bring equipment to a safe state
• 4. Isolate — open disconnects, close isolation valves, block elevated parts
• 5. Lockout/Tagout — apply your personal lock and/or tag to each isolation point
• 6. Release stored energy — bleed lines, discharge capacitors, block raised components
• 7. Verify zero energy — test with a meter before touching anything

One Lock per Worker

• Every authorized worker applies their own personal lock to a multi-lock hasp
• All locks must be removed before equipment can be restarted
• Never share a lock or use a single group lock without individual locks on the hasp
• Each person's lock protects them personally — they control when it comes off

Lock Removal Rules

• Only the worker who applied the lock may remove it
• If a worker left without removing their lock, a documented emergency procedure applies — a supervisor must attempt to contact the worker first
• Removing another worker's lock without the documented procedure violates OSHA 1910.147

Tagout vs. Lockout

• Tagout alone is NEVER as safe as lockout — tags are warning devices, not physical barriers
• A tag can be removed or ignored; a lock physically prevents re-energization
• Lockout is always preferred; tagout-only is acceptable only when equipment cannot physically be locked out
• When using tagout only, additional safety measures must supplement the tags

Key References

• OSHA 29 CFR 1910.147 — Control of Hazardous Energy
• NFPA 70E Article 120 — Establishing an Electrically Safe Work Condition