POTENTIAL CYLINDER FAILURE ALERT OF MANITOWOC 777 CRANE

PURPOSE

This note describes a type of crane with features that could possibly result in a hydraulic cylinder failure.

SUMMARY OF INCIDENT

The investigation of a near miss which occurred at the Deer Park Chemical Plant identified the failure of the hydraulic cylinder shaft on a crane that could have catastrophic potential. The crane was a Manitowoc Model 777. The failure of a boom hoist cylinder on the crane resulted in the boom falling (96 feet in 15 seconds) and coming to rest on a piperack. There were no injuries and facility damage was minimal.

Information from the report out of the Manitowoc investigation indicated that the cylinder failure was due to the shaft not being heat treated as required. In addition, the piston retainer ring was not machined to specifications. The combination of these two causes apparently resulted in the failure of the shaft.

Manitowoc officials have indicated approximately thirty Model 777 cranes are currently in service that are known to have cylinder shafts that were not properly heat treated during manufacture. Manitowoc has stated they do not intend to take these cranes out-of-service, but will replace the shafts as the new retrofits are made available.

At the Deer Park Chemical Plant this model crane will not he allowed in our facility until such time as the retrofit has been made and the appropriate documentation of the retrofit has been presented to us.

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RECOMMENDED ACTION

  • Identify if this Manitowoc model 777 crane is in use in your facility.
  • Do not operate these cranes until deemed safe.
  • Call Manitowoc to notify them of the Model 777 crane(s) at your facility and to verify that the hydraulic cylinders have been replaced.
  • Notify all personnel involved in supplying heavy equipment at your location of the information in this alert.

    For further details contact LD Smith, Manager CMATS, Deer Park Chemical by email or phone (713) 246-7826 or GW (Bo) Sanders, Coordinator, Shell Union & Management Investigation Team (713) 246-7041.