Lockout/Tagout
- Identify energy sources requiring lockout, including electrical, mechanical, hydraulic, pneumatic, chemical, and thermal.
- Perform the five-step lockout procedure to isolate and verify zero energy before beginning service.
- Implement the employer's written energy control program to prevent workplace fatalities and injuries.
- Lockout devices — Secure energy isolation points when equipment is capable of being locked out.
- Individual lock and tag — Personal protection applied to energy isolation points to prevent accidental re-energization.
- Rated mechanical blocking and wheel chocks — Use rated blocking for raised components and wheel chocks for wheel movement, as directed by the employer's energy-control procedure.
- Pressure relief valves/bleeders — Relieve stored hydraulic or pneumatic pressure during the energy isolation step.
LOTO covers electrical, mechanical, hydraulic, pneumatic, chemical and thermal energy.
Employers must have a written energy control program, use lockout devices when equipment can be locked out, and train workers.
Compliance prevents an estimated 120 deaths and 50,000 injuries a year.
How It Works
Regulatory Basis for Safety
OSHA 29 CFR 1910.147 establishes requirements for hazardous-energy control. Follow the employer's written procedure to identify, isolate, control stored energy and verify the isolation before service; a normal shutdown alone does not establish a safe work condition.
Types of Hazardous Energy
Hazardous energy in the shop environment is not limited to electricity. LOTO procedures must also cover mechanical, hydraulic, pneumatic, chemical, and thermal energy sources to ensure total equipment isolation.
Verification of Isolation
Isolating energy sources like batteries and hydraulic pressure is insufficient without verification. The final step of the procedure requires trying to operate the controls to confirm that zero energy state has been achieved.
Step-by-Step Procedure
0/5 doneDiagnostic Chart
| Symptom | Check | Spec / Expected | Likely cause & fix |
|---|---|---|---|
| Equipment is shut down but still poses a crush hazard. | Inspect for raised bodies, ramps, or mechanical components held by gravity or pressure. | Lower or block raised bodies and ramps. | Stored mechanical energy was not isolated. Basis: OSHA Fact Sheet FS-3529 Lockout/Tagout (29 CFR 1910.147) |
| Residual pressure remains in lines after pump shutdown. | Check hydraulic and pneumatic gauges or bleed points. | Relieve hydraulic pressure. | The energy isolation step failed to account for stored fluid or air pressure. Basis: OSHA Fact Sheet FS-3529 Lockout/Tagout (29 CFR 1910.147) |
| Equipment unintentionally restarts during maintenance. | Verify if locks were applied and if batteries were disconnected. | Disconnect batteries and apply your lock and tag. | Failure to isolate the electrical energy source and secure it with a lockout device. Basis: OSHA Fact Sheet FS-3529 Lockout/Tagout (29 CFR 1910.147) |
| Personnel are unaware that equipment is under service. | Confirm all affected workers were contacted before shutdown. | Notify affected workers. | Communication failure during the initial step of the LOTO process. Basis: OSHA Fact Sheet FS-3529 Lockout/Tagout (29 CFR 1910.147) |
At the Bay: Diagnose the Case
CASE 1 / 4
Equipment is shut down but still poses a crush hazard.
- Test
- Compare
- Correct
Select the next check
Basis: OSHA Fact Sheet FS-3529 Lockout/Tagout (29 CFR 1910.147). A likely cause is a hypothesis; confirm it with the applicable service procedure before repair.
Common Bay Mistakes
- ✕ Failing to notify affected workers before shutting down equipment.
- ✕ Assuming a normal shutdown is the same as energy isolation.
- ✕ Neglecting to block raised ramps or bodies because the hydraulics are off.
- ✕ Forgetting to disconnect batteries as an electrical energy source.
- ✕ Skipping the verification step to 'try' the controls before starting work.
Quick Check
Practice only — not scored.
Plan the Service Sequence
Planning practice only. Follow the applicable manufacturer's instructions, employer safety program and qualified supervision on real equipment.
Plan the first action. Compare the service steps with the bay mistakes.
Source: OSHA Fact Sheet FS-3529 Lockout/Tagout (29 CFR 1910.147)