Mechanical isolation prevents the unintended movement of machinery, rotating equipment, and mechanical systems during maintenance and construction work. Unlike electrical isolation, mechanical isolation must also address stored energy from springs, gravity, hydraulic pressure, and compressed air. This talk explains the mechanical isolation procedure and the checks every operative must complete before working on mechanical equipment.
Key Hazards
Unexpected machinery start-up causing crushing or amputation injuries
Stored energy release from springs, counterweights, or pressurised systems
Gravity-driven movement of elevated loads or hinged components after isolation
Incomplete isolation missing secondary drive systems or backup power sources
Control Measures
Identify all mechanical energy sources connected to the equipment including drives, belts, and shafts.
Shut down the equipment using the normal operating controls before applying any mechanical isolation.
Engage mechanical locks, pins, or blocks to prevent movement of all moving parts.
Apply a personal safety lock and danger tag to every isolation point and mechanical restraint.
Release or restrain all stored energy from springs, hydraulics, pneumatics, and elevated loads.
Verify the equipment cannot move by attempting to operate it after isolation is complete.
Ensure all persons working on the equipment apply their own individual lock before starting.
Do not remove chocks, pins, or blocks until all locks are removed and it is safe to re-energise.
Record the isolation details on the permit to work including all isolation points and lock numbers.
Remember
Identify all mechanical energy sources including drives, belts, shafts, and stored energy systems
Engage mechanical locks, pins, or blocks to physically prevent movement of all moving parts
Apply your personal safety lock and danger tag to every isolation point before starting work
Release or restrain all stored energy from springs, hydraulics, pneumatics, and gravity loads
Verify the equipment cannot move by attempting to operate it after all isolations are complete
Record all isolation points and lock numbers on the permit to work before starting
Applicable Legislation: PUWER 1998 · Health and Safety at Work etc. Act 1974 · Management of Health and Safety at Work Regulations 1999 · Pressure Systems Safety Regulations 2000