Tower crane spigot alert

Manitowoc/Potain has issued a service bulletin and warning regarding a batch of substandard tower spigots on its K600 and K800 tower sections. The bulletin has also been referenced by a UK HSE warning notice.

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.

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

Manitowoc Crane care says that the K600 and K800 series mast sections are only used on its MD, MDT and MR series cranes. Each tower section has a unique PIN /identification number. The numbers for mast sections produced in this time period are between 80323 - 103784.

The potentially affected spigots are in the ranges 3086* to 3496* and 0037* to 0577* - the letter on the end of the reference number is irrelevant for identification.

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.

If it is not possible to dismantle a crane that has a potentially bad section within tts tower, Manitowoc crane care can help you add some factory approved re-enforcements intended to last until the end of the job or until a break in the work load. If in doubt at all contact Steve Bradby at Manitowoc cranes UK in Gawcott, Buckinghamshire.

The HSE Bulletin reads as follows:

"We are aware of two crane mast failures in which faulty mast section spigots were implicated."

"The first of these incidents was in Chicago in February 2009. The most recent incident involved a crane in London in April 2010. Metallurgical tests undertaken on the London crane showed that the spigot failed catastrophically in brittle fracture from a small fatigue crack. The tests have shown that the failed spigot did not meet the performance characteristics specified for the component. It is believed that there was a flaw in the heat treatment process during the manufacture of the spigot. Whilst investigations continue to isolate the cause of the problem, as a precaution all spigots manufactured between 1 November 2006 and 28 Feb 2007 are suspected of being substandard and subject to the remedial action outlined in this document"