03.11.2014

The UK’s HSE reminds on slew brake checks

The UK’s health & Safety Executive issued a safety alert on Friday reminding those owning or responsible for tower cranes to properly check and maintain their slew brake release mechanisms.

The warning has been generated from investigations into incidents involving jib collapses, where it believes problems with adequate maintenance of the slew brake release mechanisms was a factor.

The safety alert advises owners and users of “steps to be taken to ensure that tower crane slew brake release mechanisms are maintained in an efficient state, in efficient working order and in good repair. 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. This alert provides supplementary information to HSE Health and safety bulletin FOD 2-2014 Preventing catastrophic failure of luffing jib tower cranes in high winds”.

“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”.

As a result of these ‘findings’ the HSE warns owners and users of tower cranes to ensure that tower crane slew brake release mechanisms are inspected and maintained in line with instructions issued by the manufacturer. And advises that where manuals do not provide maintenance instructions they should ask manufacturers to provide details.

Crane operators should also be provided with details of how slew brake release mechanisms should be checked, inspected and maintained, including the type of lubrication and the frequency and method of applying lubrication to the release mechanism.

It also advises that supervisory checks should be carried out to confirm that the maintenance is correctly carried out and that the crane is being placed in free slew when left out of service. Finally it adds that “Persons carrying out Thorough Examinations should also confirm the correct function of the slew brake release mechanism”.

Vertikal Comment

While the alert does not specifically mention them, this warning has been generated by two of five jib collapses on Jost hydraulic luffing jib cranes in the UK - one in late 2011, one in April 2013 - although to be fair this incident was different from the other three - two in October 2013 and one in February 2014. Since then we understand that Jost has designed a modification kit to one of the jib connections in order to strengthen it to cope better with high winds when the jib is forced to remain at a high out of service angle.

The unacceptable fact of this is how long it has taken for the HSE to publish this, if a badly maintained slew brake release was part of the cause then it would have known this within the first few weeks of the investigation. Or should have done. It certainly hasn’t just found out in the last week or two!

As far as we know these reported factors could have been discovered on the first incident back in 2011. In which case we might have prevented the others from happening? At least we were lucky this time in that no one was seriously hurt or injured. One wonders though if the publication might have been spurred on by the high winds of the past couple of weeks or not?

We believe that the HSE must be allowed to focus on getting information out to the market and that this should be above retaining it in order to use it for possible prosecutions. This already happens with air accident investigations so why not with cranes and aerial lifts?