Uncoupling of Hydraulic Excavator Buckets a Hazard
A worker was fatally injured at this site in Wisconsin by a bucket disconnecting from an excavator.
An Aug. 26 bulletin from the Occupational Safety and Health Administration advises employers who use hydraulic excavators with quick coupling devices of the potential for injury and death from the unintentional release of a bucket or other attachment from the coupler.
The OSHA advisory follows a fatal accident in Madison, Wis. caused by the unexpected release of an excavator bucket from a quick coupling device on a hydraulic excavator at a site where a contractor was installing water mains and laterals.
While an employee was entering a freshly dug lateral to install a pipe, the excavator operator changed buckets using a quick coupler on the excavator. When the excavator was swung to continue digging on the main line, the bucket became detached from the coupler and rolled or slid into the lateral excavation, striking and killing the employee. The investigation of the incident found that a locking pin had not been manually installed on the coupler to prevent the accidental release of the bucket.
A review of OSHA’s database found 14 additional incidents that were similar within the last six years, eight of which resulted in employee fatalities.
OSHA noted that these accidents appear to still be occurring despite efforts by manufacturers to retrofit existing quick couplers, design new and improved coupler systems and develop safe procedures for using them.
Employees can be protected from the release of attachments by:
- Inspecting quick couplers to determine if they are hazardous and determining whether a manually installed locking pin and installation procedures, or other retrofitting methods, have been provided by the manufacturer
- If appropriate, obtaining and installing retrofits recommended by the manufacturer, including positive locking pins and other devices that need to be manually installed
- Using an independent secondary system to prevent the attachment from falling if the primary system fails. This can be manual or automatic, with a procedure for the user to verify proper attachment.
- Considering using newer coupler models that have been specifically designed to prevent the unintended release of attachments
- Following the manufacturer’s recommendations for maintenance and inspection of the quick coupler to prevent a malfunction that could cause an unintended release of the attachments
- Following the manufacturer’s installation procedures and recommendations for using and testing quick coupler devices and four attachment connections whenever an attachment is made
- Training employees in the proper use of quick couplers, making visual inspections, procedures for engaging attachments and methods for testing connections
- Requiring employees to use the proper procedures for engaging excavation attachments and incorporating the procedures into the company’s safety and health program
To read the bulletin, “Hazards of Inadequately Securing Hydraulic Excavator Buckets When Using Quick Coupling Devices,” click here. The OSHA advisory includes detailed figures of a quick coupler.
For more information, e-mail George Middleton at NAHB, or call him at 800-368-5242 x8590.
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