Workplace safety and crane maintenance
Workplace safety and crane maintenance joins the two things behind most crane incidents: an uncontrolled hazard and an unmaintained machine. The exam tests exclusion zones, overhead line distances, weather limits, personnel lifting rules, and the inspection and tagging regime that stops a defect reaching the hook.
Control the zone
- Barriers and signage around the slew and load path; no person under a suspended load.
- No riding the load, the hook or the ball.
- Personnel lifting only from a purpose-built, tested platform with restraint, low-speed controls, radio contact and a documented plan.
- Overhead lines: minimum approach distances under NZECP 34, commonly 4 m for distribution lines; use a spotter or isolation, and always treat lines as live.
- Weather: wind measured at boom tip or load level, allowing for sail area; stop for lightning, poor visibility or the chart's wind limit.
Maintain and inspect
- Operator pre-start checks each shift; periodic inspection by a competent person at the intervals set by the approved code of practice and AS 2550.1, commonly 12-monthly for cranes and 6-monthly for lifting gear, more often in harsh conditions.
- Wire rope discard: broken wires, diameter loss, corrosion, kinks, birdcaging.
- Hook discard: throat opening increase over 10%, wear over 10%, twist over 10 degrees, cracks or deformation.
- Tag any defect out of service immediately; repairs and modifications only by competent persons, with proof load testing after structural repair or major alteration.
Worked example
A hook is measured against its original dimensions: throat 64 mm, now 70 mm, an increase of 9.4%, inside the 10% limit; saddle wear 6%, acceptable; but the hook is twisted 12 degrees, past the 10 degree criterion. Any single exceedance condemns the hook, so it is removed, tagged and replaced. Check the latch and swivel at the same time.
Traps that cost marks
- Recording a defect in the log without tagging the machine out of service.
- Relying on the annual inspection as the only inspection.
- Measuring wind at ground level instead of at the load.
- Treating a short lift as needing no exclusion zone.