MSHA has urged the use of qualified welders to inspect welds and metal components, and also to train users, after taking note of several fatalities that were tied to damaged or defective welds on aerial lifts.
In one noted incident, a mechanic died while being lowered in an electro-hydraulic aerial lift. In that event, a weld splice fractured on a recently repaired lift arm, which resulted in the arm striking the victim in the head. MSHA found that the weld failed because of poor weld quality from an improper repair.
In another incident MSHA reviewed, a welder died while being lowered in an electro-hydraulic aerial lift. The lift arm in this case “catastrophically fractured” at a critical weld point where the arm support was connected to the lift cylinder. It also found that the weld and surrounding metal had undetected cracks before the failure.
In its release of best practices, MSHA asked that mines have only qualified welders perform all welding duties at mines, and inspect welds after installation and repairs along with routinely over its service life.
Additionally, workers should determine the service/fatigue life of mechanical systems or parts by consulting with the manufacturer, and routine examinations should be performed of metal components for signs of weakness, corrosion, fatigue cracks, bends, buckling, deflection and missing connectors.
Finally, MSHA said nondestructive test methods should be employed to detect indistinguishable cracks, and all cracked mechanical components should be removed from service. All workers, too, should be trained in proper lift operation, including not exceeding their design capacity.