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OSHA Safety Hazard Information Bulletin on Retrofit of Boom Pin Retention
Assembly on Digger Derricks and Vehicle-Mounted Elevating and Rotating Work Platforms
May 5, 1998
In October, 1996, the Mine Safety and Health Administration (MSHA) investigated an accident involving a two-man crew who were using a hydraulically operated digger derrick crane to remove power lines from a utility pole. MSHA determined that through lack of proper inspection and maintenance, the boom pin retention assembly failed. It was also determined that such equipment may need to be retrofitted with a redesigned boom pivot pin.
Although the original problem was identified on a truck derrick manufactured by Altec Industries, this condition may exist on truck derricks and similar equipment manufactured by any company. In connection with their investigation, MSHA issued a Memorandum on retrofitting of boom pivot pins on digger derricks manufactured by Altec Industries. Table 1 provides a list of Atlec Industry units that have been identified as affected by the recall program. This equipment is typically used for power line maintenance, construction, general industry and other above ground work. OSHA has concluded that it is appropriate to expand MSHA's warning to indicate that there is a potential hazard with similar equipment used in general industry and in the construction industry if it is not properly inspected and maintained.
The Office of Science and Technology Assessment has determined that the pin failure as described by MSHA investigators represents a significant risk if the subject units are not properly maintained. MSHA's memorandum provided the following information.
Investigators from MSHA's Pittsburgh Safety and Health Technology Center and Approval and Certification Center (A&CC) reported that a digger derrick was involved in an accident in Hutchinson, West Virginia. The digger derrick had not been retrofitted in accordance with Altec Industries's Service Bulletin No. SB-D-203, dated February 1, 1988.
This Service Bulletin details a method for strengthening the boom pivot pin retention assembly. The Service Bulletin indicates that units in service do not require replacement of end cap bolts if the owner properly inspects the boom pivot pin regularly. The accident investigation found that inadequate inspection of the boom pivot pin allowed an unsafe condition to go undetected.
Altec's Service Bulletin (SB-D 203) was issued because failure to inspect the boom pivot pin in accordance with the owner's manual could lead to pin failure. Notices of the Bulletin were reportedly sent to all customers who had purchased the derricks.
Altec Industries, Inc. reported that the number of retrofitted units has not been documented. They did report that:
1) The total number of units affected by Service Bulletin Number SB-D-203 was approximately 2,306; andAltec's representative reported that boom pivot pin assemblies are replaced by Altec on any derrick returned for servicing. All derricks produced since 1988 reportedly use the redesigned pin assembly. However, some digger derricks equipped with the original pivot pin may still be in service. The serial numbers of the machines affected by this retrofit are attached.
Altec reports that no accidents have been reported involving retrofitted machines.
There are no markings or labels applied to retrofitted units to identify them. The only visible differences in the boom pivot pin retention system are:
1) The roll pin has been replaced with a cap screw on one end; andAltec Industries, Inc has indicated that they will continue this retrofit program for the identified units until all the units have been accounted for.
This Hazard Information Bulletin underscores the need for employers, as well as for OSHA Inspectors, to inspect all boom pivot pins to ensure that they are in good working order. OSHA regulations (29 CFR 1926.550) contain general inspection requirements for cranes, derricks and hoists. These requirements are applicable irrespective of whether or not such equipment may have been retrofitted.
Please distribute this bulletin to all area offices, State Plan States, Consultation Projects and appropriate local, labor and industry associations. Copies of the HIB may be used for outreach purposes.
Table I List of Affected Serial Numbers