LOT/Specific/TBT-LOT-003

Mechanical Isolation

Lock Out Tag Out › Specific › Mechanical Isolation

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Mechanical isolation disconnects equipment from its mechanical energy source to prevent unexpected movement during maintenance.
Mechanical energy sources include rotating shafts, gears, belts, chains, hydraulic rams, pneumatic cylinders, and springs.
Unexpected start-up or release of stored mechanical energy causes crushing, trapping, and amputation injuries.
The isolation procedure must identify every mechanical energy source connected to the equipment before work begins.
Physical locks must be applied to isolation points — warning tags alone cannot prevent accidental re-energisation.
Stored energy such as pressurised hydraulic accumulators, compressed springs, and raised loads must be released after isolation.
Each person working on the isolated equipment must apply their own personal lock to the isolation point.
Gravity is a mechanical energy source — raised loads, counterweights, and suspended components must be blocked or lowered.
Trial operation after isolation confirms the equipment cannot move — attempt to start it to verify the isolation is effective.
Only the person who applied a lock may remove it — the equipment must not be restarted until all locks are removed.

Crushing and amputation	Unexpected movement of mechanical equipment traps, crushes, and amputates — physical isolation prevents the machine from moving.
Stored energy	Pressurised hydraulics, loaded springs, and raised masses remain dangerous after the power source is disconnected — they must be discharged.
Personal lock	Your lock guarantees the machine stays isolated while you are working on it — no one else may remove your lock.

Don't

Identify all mechanical energy sources before starting the isolation procedure.
Apply physical locks to every isolation point on the equipment being maintained.
Release stored energy in hydraulics, pneumatics, springs, and raised loads after isolation.
Lower or block all suspended loads and counterweights before starting work.
Apply your own personal padlock and tag to the isolation point before starting.
Attempt to start the equipment after isolation to verify it cannot move.
Use a multi-lock hasp when more than one person works on the same equipment.
Follow the site-specific LOTO procedure for each piece of mechanical equipment.
Keep your lock key on your person throughout the duration of the isolation.
Remove your lock only when your work is complete and the area is confirmed safe.

DON'T work on mechanical equipment without completing the full isolation procedure.
DON'T rely on tags alone — physical locks must prevent the equipment from restarting.
DON'T forget stored energy — hydraulic pressure and raised loads remain dangerous after isolation.
DON'T work beneath raised loads without lowering them or installing physical blocks.
DON'T allow anyone else to lock off on your behalf — apply your own personal lock.
DON'T skip the trial start — it is the only way to confirm isolation is effective.
DON'T share locks between workers — each person must have their own individual lock.
DON'T improvise the isolation procedure — follow the site-specific LOTO process.
DON'T leave your lock key unattended or hand it to someone else during the isolation.
DON'T remove another person's lock under any circumstances — only they may remove it.

See also: Lock Out Tag Out (LOTO) Awareness | Electrical Isolation

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