Plant and Machinery: Pre-Start Checks, Operation and Isolation
Pre-start checks
Before operating any machine, the operator carries out a pre-start inspection: fluid levels, tyres/tracks, guards and interlocks in place, brakes, steering, horn, lights, seat belt, fire extinguisher, and no leaks or damage. Defects are recorded and reported; a machine with a safety-critical defect is not operated. Questions often test that the check is the operator's responsibility and that defects must be logged even if the machine still works.
Isolation and lock-off
Before maintenance or clearing blockages, plant must be isolated from all energy sources - electrical, hydraulic, pneumatic, gravity (raised components), and stored pressure. Isolation means: switch off, isolate, lock off with a personal lock, prove dead, and dissipate stored energy. Only the person who fitted the lock removes it, under a defined procedure. Traps: assuming a stop button isolates; assuming a guard interlock is isolation; leaving keys in.
Operation
Operate within design limits, keep guards in place, never remove or defeat interlocks, and follow the manufacturer's instructions. Report abnormal noise, vibration or overheating.
Worked example
A fitter needs to replace a screen mesh. Correct sequence: permit/authorisation, stop and isolate, personal lock and tag, prove dead at the point of work, block any raised component, complete work, remove tools, remove lock, test run. Restarting because "the operator is waiting" is never acceptable.