Worksafe Victoria, The Health and Safety Executive, and Manitowoc have issued a Safety Alert about faulty tower spigots on K600 and K800 tower sections following two known mast section failures.

The warning follows two catastrophic spigot failures, one in Chicago in February 2009 and one in London this April. The failure, which starts as a small crack, is thought to be due to inadequate heat treatment.

If a tower crane mast fails and collapses there is potential for multiple fatalities.

Read the warning here.

Tower crane masts or towers are constructed from a number of individual sections which are located one on top of another to achieve the required height. For the type of cranes covered by this safety notice, spigots provide a means of connecting individual mast sections together. Their condition is crucial to the integrity of the mast.

A manufacturing defect has been identified in spigots used on K600 and K800 mast sections used in Manitowoc Cranes, Potain MD, MDT and MR Tower Cranes. There have been two known mast section failures from this cause. Action is needed to identify any other potentially affected mast sections and ensure they are taken out of service immediately then quarantined for further investigation.

While investigations continue all spigots manufactured between 1st November 2006 and 28th February 2007 are suspected of being substandard and subject to replacement.

The action required is easy. For stored sections they simply need to be checked to see if they are within range and then the spigots changed, or at least checked.

For cranes in service the sections need to be checked to see if any of them are included in the list of potential affected sections. If a potentially bad section is identified, it must be pulled out of service immediately and then the spigots checked to see if any of them are potentially substandard.