You may not realize it, but digger derricks
play an important role in our everyday lives. Companies use these vehicles to dig holes and set the poles used by electrical utility and telecommunication companies, as well as those used for signage and outdoor advertising.
With so many different parties involved in the process, there are many considerations to keep workers safe while operating these vehicles. These three factors are particularly important to address to safeguard workers who use and operate digger derricks.
1. Find the Right Fit
While many factors contribute to the safe use of digger derricks, one key is making sure you have the right equipment for the job.
“The quality of a digger derrick is best measured by the fit it has with the work that needs to be performed,” says John Brewington, chair of the A10.31 subcommittee. “To pair an owner with the correct digger derrick, the dealer needs to know the expectations for the machine.”
Brewington encourages owners and users to ask these questions when purchasing a digger derrick:
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What kind of loads will it handle and at what lift radius?
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Will it be insulating?
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Will it need to carry personnel aloft?
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What type and size carrier is needed to take it where it needs to go?
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What is the payload required?
Owners should seek input from operators to answer these questions, Brewington says, then use this information to develop performance-based specifications to share with potential suppliers.
2. Understand the Hazards
Once you’ve selected a digger derrick that meets your specific needs, you need to understand the hazards and risks that users and operators will face in different working environments.
Working with digger derricks presents unique hazards. Given that the machines are involved in excavation, working with heavy materials and potentially coming in close contact with utility lines, you need to assess several risks.
“All digger derricks present risks associated with instability during operation,” says Brewington. “Instability of a digger derrick suspended and moving loads and electrical contact can lead to catastrophic consequences for the operator or others in or near the work site.”
A range of issues can cause this instability, including improper set-up of the vehicle and unstable support surfaces such as soft ground, untamped trenches or subsurface chambers such as utility or septic systems.
To address potential stability issues, A10.31 requires designers to use specific minimum structural safety factors for different types of digger derrick components. Design analysis must also consider stresses that occur when operating on slopes and during transport.
Other common hazards include contact with energized electric lines, or underground gas, electric or water lines. To help prevent possible electrical contact, Brewington notes that it’s important to remember that not all digger derricks are designed and rated for working in close proximity to energized lines and equipment. Those rated as “insulating” must meet the electrical systems, devices and test procedures requirements described in section five of A10.31.
Brewington emphasizes the importance of conducting a site inspection before any digger derrick work commences to ensure that workers understand the capabilities of the equipment and know how to operate it safely in specific work environments.
“Manufacturers or installers specify the conditions in which the machine needs to be set up,” he says. “Generally speaking, digger derricks must be set up on level ground and that is accomplished by changing the stability with outriggers, by cribbing or other methods.”
He also stresses that if an operator has any concerns about the condition or appropriateness of the equipment, work should stop immediately and not resume until the concern is resolved.
3. Train and Maintain
To safely use any vehicle, the operator must understand how to use it properly. In addition, an organization must routinely perform equipment maintenance. Digger derricks are no different.
“Timely and appropriate inspection, maintenance and testing are key factors in staying safe,” says Brewington. “Operators must be trained and properly supervised in the use of the equipment for the work intended.”
A10.31 states that digger derrick owners should set inspection and testing intervals to examine the vehicle for damage and defects in accordance with manufacturer recommendations. Inspection frequency depends on a component’s function and its exposure to wear and deterioration. The standard designates two classifications for inspection and testing:
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Frequent inspection and test: daily to monthly intervals
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Periodic inspection and test: one-to-12-month intervals
A frequent inspection could take place before the first use in each work shift and should include a visual examination to look for damaged components, a check that controls and mechanisms are operating correctly and functional tests. The periodic inspection and test include an examination of structural members for deformation or corrosion, as well as an examination of hydraulic components and welds.
With respect to operator training, A10.31 states that “only personnel who have received general instructions by a qualified person regarding the inspection, application and operation of digger derricks, including recognition and avoidance of hazards associated with their operation, shall operate a digger derrick.”
The standard outlines several training criteria and resources for operators, including:
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Responsibilities associated with problems or malfunctions affecting operation
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Applicable safety rules and regulations
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Proper use of fall protection equipment for digger derricks equipped with platforms
Brewington encourages owners, users and installers to consult other relevant resources to ensure that work is performed safely on the job site. “Organizational work rules, OSHA regulations and consensus standards such as A10.31 and digger derrick operator manuals are great resources for working efficiently and safely across various industries,” he says.
The 2019 update of the ANSI/ASSP A10.31 standard is available now. The changes in this revision of the standard take effect June 1, 2020.
Listen to our podcast with A10.31 subcommittee chair John Brewington for further insights on digger derrick safety.
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