Lockout Tagout
Lockout tagout, or LOTO, is a controlled process used to isolate hazardous energy and prevent unexpected equipment startup or energy release during work.
What this term means in maintenance
Lockout tagout, or LOTO, is a controlled process used to isolate hazardous energy and prevent unexpected equipment startup or energy release during work.
Hazardous energy sources
LOTO may be required for:
- Electrical energy
- Hydraulic pressure
- Pneumatic pressure
- Mechanical movement
- Stored spring energy
- Gravity
- Steam
- Thermal energy
- Process chemicals
Typical LOTO sequence
A controlled process normally includes:
- Identify energy sources
- Notify affected personnel
- Shut down equipment
- Isolate energy
- Apply locks and tags
- Release stored energy
- Verify zero-energy condition
- Perform the work
- Inspect and clear the area
- Remove locks under authorized rules
- Restore equipment safely
Practical example
Before replacing a conveyor drive, the electrical supply is isolated and locked, pneumatic tension is released, gravity hazards are blocked, and zero energy is verified.
Personal control
Locks and tags should identify the authorized person and remain under controlled removal rules.
Common mistake
Pressing a stop button is not energy isolation. The team must isolate and verify every hazardous energy source.
How this term differs
Lockout Tagout is the lock, tag, authorization, and verification process used to secure isolations. It is related to Energy Isolation, Electrical Isolation, and Mechanical Isolation, but these terms describe different records, measures, roles, strategies, or decisions and should not be used interchangeably.
Related concepts
Related maintenance terms
Keep exploring connected CMMS, reliability, and maintenance planning terms.
Permit to Work
A permit to work is a formal authorization confirming that defined hazards, isolations, precautions, responsibilities, and validity conditions are controlled before high-risk work begins.
Work Instruction
A work instruction is a clear, task-level description of how a specific maintenance activity should be performed safely and correctly.
Critical Asset
A critical asset is equipment whose failure could create an unacceptable impact on safety, environment, product quality, compliance, production, or business continuity.
Glossary FAQs
- What does LOTO stand for?
LOTO stands for Lockout Tagout.
- Is pressing the stop button enough for LOTO?
No. Hazardous energy must be physically isolated, controlled, and verified.
- What energy sources should be considered?
Electrical, hydraulic, pneumatic, mechanical, thermal, gravity, steam, chemical, and other stored energy sources.