Lockout/tagout (LOTO)
A safety procedure that isolates and locks energy sources so equipment cannot start during maintenance.
How it works
Before working on a machine, the worker shuts it down and isolates every energy source: electrical, hydraulic, pneumatic, mechanical, thermal, and gravity. Each isolation point gets a personal lock and a tag that says who locked it and why. Stored energy, such as pressure in a line or a raised load, is released or blocked. Then the worker tries to start the machine to verify that it stays dead.
Only the person who applied a lock removes it. When several people work on the same machine, each adds their own lock, often on a multi-lock hasp.
Why it matters
Unexpected start-up and release of stored energy cause serious injuries during maintenance. LOTO is the standard control. In the United States it is required by OSHA under 29 CFR 1910.147, the control of hazardous energy standard. Other countries have their own rules; follow the regulations and site procedures that apply to you.
In practice
Good LOTO depends on machine-specific procedures that list every isolation point. Those procedures are often kept in a binder in an office, far from the machine. Teams that post the procedure at the machine, or link it from a label, make it easier to follow the right steps every time.
LOTO steps are often part of the work order for any job that opens a guard or a panel.