Improper rigging maintenance can lead to shocking (and deadly) results
When shock loading occurs in a rigging operation, the results can be devastating. An equipment failure can take place at the time the shock load happens. In many cases, it can be weeks, months, or even years later.
What is shock loading?
Shock loading refers to the sudden and forceful application of a heavy weight onto a weighing balance or scale. While the term might initially evoke electrical connotations, in this context it pertains to the careful handling of weighing equipment.
Notably, shock loading can occur even when the weight being applied does not exceed the equipment’s designated capacity. Even a relatively light weight, when dropped from a moderate height, onto the pan can generate a destructive force. This compounding of weight takes its toll on the load’s internal and external structure, rigging attachment points, and entire hoisting system.
It is essential to note that what qualifies as a “heavy weight” can vary depending on the specific balance or scale being used. The impact of a weight on one balance may differ significantly from its effect on another.
The consequences of shock loading
At a minimum, shock loading may disrupt the calibration of the weighing equipment. This can lead to inaccuracies in subsequent measurements. In more severe cases, shock loading could inflict permanent damage, affecting the device’s overall functionality. It is crucial to exercise caution and proper handling techniques to avoid subjecting weighing equipment to shock loading scenarios.
Frequent exposure to shock loading situations can have disastrous consequences. It may lead to broken welds, metal fatigue fractures, or damage to the hoist system and wire rope. Imagine the cumulative effect of such incidents happening twice a month for four years – a recipe for disaster.
Examples in the real world
An alarming reality is that an employee, often not involved in creating the equipment’s damage, might be the one injured or killed when your crane fails. Accidents are not caused solely by the immediate load, but by the result of years of repeated shock loading and structural damage.
In an industrial setting, shock loading is a common occurrence that can lead to severe equipment damage and potential safety hazards. One such case is observed at a coal-fired steam plant that employs pulverizer journal assemblies to crush coal into a fine powder. The handling process involves turning, or flopping, the journals over from one plane to another.
During a “trolley and flop” movement, the impact of the journal arms against their chain slings creates a cloud of dust and dirt, raising concerns about potential structural damage to the crane. The weight introduced to the crane during this process raises questions about the integrity of the equipment. Often, the equipment cannot withstand such repeated abuse over time.
Preventing shock loading
To prevent such catastrophic events and safeguard both your personnel and equipment, it is crucial to implement alternative rigging methods. Conducting comprehensive inspections of your hoisting and rigging components is vital, and load tests should be performed using proper procedures. Collaboration with the equipment manufacturer for testing procedures and limitations is also essential to ensure reliability and adherence to safety guidelines.
By prioritizing safety, adopting best practices, and being vigilant about shock loading hazards, industrial operations can significantly reduce the risk of accidents, protect their assets, and most importantly, safeguard the well-being of their workforce.
Happy Rigging!
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