TECHNOLOGY REPORT | SAFETY
At 9:30pm on April 21, 2021, an employee was using an
overhead crane to set a press die on a bolster. While attempting to adjust the die’s position on the bolster, the die swung out toward the press crushing the employee between the die and the press. The employee died from his injuries. OSHA accident report number 135004.015
Employee Is Killed When Struck By Swinging Press Die
busy factory floor. These are increasingly inexpensive systems to install and if are not yet the norm they are certainly now everyday fitments to any new hoist, and can be retro-fitted as well.
BELOW-THE-HOOK There is another link in the load-path that is easy to overlook but which is just as important: it is the below-the-hook device that attaches the load to the hook. (Again, see the part that this played in the second of our reported OSHA fatalities, even though in that case the below-the- hook device behaved as it was designed to.) Slings, shackles, rigging hardware, even vacuum lifters are all included here. Henry Brozyna is an industry
product trainer at Columbus McKinnon specializing in crane and hoist inspection and repair, rigging, and load securement; he is also a former member of the Board of Directors for the WSTDA (Web Sling & Tie Down Association) , which writes the standards that are used by the material handling industry, the transportation industry, and also law enforcement. “In the US, when it comes to below- the-hook lifters, there are standards in place, including ASME B30.20 and BTH-1, that outline the design, manufacture, use and inspection of this equipment,” he says. Riggers and operators frequently attach the load to the hook onsite using combinations of slings, shackles and spreaders. “While many of these lifters are “homemade,” that in itself does not disqualify them from service,” says Broznya. “What typically disqualifies a lifter from service is the lack of labelling, ID tags or engineering to back up the design.
“ASME BTH-1 details the design” he
says. “Two of the most important things that help dictate the design of a lifter are the load that will be lifted and the environment the lifter will be used in. “The most common design classification is Design Category B, which has a minimum 3:1 safety factor. Design Category B should be designated when the magnitude and variation of loads applied to the lifter are not predictable or where the loading and environmental conditions are severe or not accurately defined. This category would include most engineered spreader beams. “Once the design is established, BTH-1 specifies the lifter must be rated for a service class. The service class takes into account the number of load cycles a lifter will see during its lifespan. “Every time a lifter is used, it flexes, and
if it flexes enough times it will fracture – this is called Fatigue. Fatigue needs to be taken into consideration to ensure safety and long life of the lifter. Three questions
that will help the engineer determine Fatigue and the Service Class of the lifter are: How long do you plan on using this lifter? How many times a day will the lifter be used? And: What capacity loads do you expect to be lifting? In BTH-1, the most common Service Class is 2, which rates the lifter for 100,001 - 500,000 load cycles.” “Once the lifter is designed and built, it must be tagged. If a lifter weighs more than 100 lbs., the weight of the lifter must appear on the tag. The tag is a very important part of any lifter. It shows who built it, what its Working Load Limit (WLL) is and the design criteria used. If the lifter employs motors, electrical information must also appear in the tag, including amps and voltage requirements.” Although safety in lifting may seem to
be largely common sense, it also requires the best of design and technology, the best in training, and ceaseless vigilance at all times. As the OSHA accident reports show, a moment’s inattention can bring appalling and irreversible harm. ●
www.hoistmagazine.com | October 2022 | 45
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