Maintenance issues in UK tower crane collapses

A safety alert bulletin published by the Health and Safety Executive in the UK points to maintenance issues where the jibs collapsed on two tower cranes.

The purpose of 31 October 2014 HSE bulletin is to alert owners and users to the importance of properly maintaining tower crane slew brakes in efficient working order and in good repair. It follows investigation into the collapse of the jibs on two tower cranes during high winds on job sites in London.

“The emerging findings from the HSE investigations indicate that the operational efficiency was compromised by lack of maintenance, in particular, insufficient lubrication of the slew brake release mechanism.”

In detail the bulletin continued, “Failure to maintain the release mechanism can result in the operator being unable to fully release the slew brake when placing the crane in the out of service condition or the operator thinking that the slew brake is fully released when it is still partially engaged. If the brake is not fully released the upper slewing structure will not be able to slew freely in response to changing wind directions. This could result in the jib or whole crane collapsing in strong winds.”

Maintenance should be carried our as per the crane manufacturer’s instructions. Where these are not stipulated in the manuals, handbooks, etc. details should be obtained from the manufacturer, HSE said. Instruction should be provided to operators and maintenance personnel as to how slew brake release mechanisms should be checked, inspected and maintained. This should include information, where necessary, as to the type of lubrication and the frequency and method of applying lubrication to the release mechanism, the safety alert continued.

Further, the bulletin stated that supervisory checks should confirm that personnel are correctly carrying out their instructions and the crane is being placed in free slew when left out of service. During a Thorough Examination the correct function of the slew brake release mechanism should also be confirmed.

The safety alert supplements the earlier HSE health and safety bulletin FOD 2-2014 Preventing catastrophic failure of luffing jib tower cranes in high winds.