Journal of Commerce | PROJECTS | by JOC NEWS SERVICES | Oct 11, 2016
VANCOUVER – WorkSafeBC is warning employers to make sure crane equipment is properly inspected after several close calls due to failing gearboxes.
A tower crane operator had just finished hoisting formwork from the upper level of a concrete residential highrise to its first level, and was hoisting the load block while advancing the trolley toward the mast. Without warning, the empty hook, load block, and rigging chains, (about 1,000 pounds altogether) plummeted to the ground, the load line spooling around them. No workers were injured, but several were working in close proximity to the falling equipment.
Inspection of the hoisting gearbox revealed that a gear had broken in half during operation. Lab tests showed that the gear was made of defective metal and prone to cracking, breaking down and failing during operation.
Other tower crane gearboxes have failed, most recently during a lift in Alberta in fall 2015. In this case, as above, regular and thorough gearbox inspections could have identified gears needing repair or replacement. Such inspections are key to preventing crane equipment collapses and serious or fatal injuries.
WorkSafeBC officials recommend that contractors regularly inspect and maintain all tower crane gearboxes according to the manufacturer’s instructions. They should also seek written confirmation of the equipment’s fitness for service from an engineer or a person designated as qualified by the manufacturer.
In the absence of a manufacturer’s inspection criteria, it’s advised to develop and implement an appropriate inspection and preventive maintenance program for all gearboxes.
Those using the equipment should pay particular attention to signs of gear fatigue or cracking. WorkSafeBC urged users to consider using X-rays or magnetic particle testing to detect hidden flaws.
WorkSafeBC also advised repairing or replacing damaged or defective parts immediately and have those repairs certified by a professional engineer, or, if available, by the original equipment manufacturer.
It’s also good to keep detailed reports of gearbox tests, inspections, maintenance, repairs and modifications and pre-start inspections for the service life of the equipment.
Finally, WorkSafeBC asked crane users to keep the equipment logbook up to date. Make the logbook available on request to workers, supervisors, the operator and the person responsible for inspecting, testing, or maintaining it, as well as anyone else on the site.