Dropped Objects: Two Types or Three?

By Arnold Marsden, author of "Don't Let It Fall: Stop Dropped Objects, Save Lives"

We have been schooled in two types of Dropped Objects, Static and Dynamic, for decades. These terms originated in the Oil and Gas Drilling industry, which has done most of the pioneering work in this area. We are indebted to them for that! However, once you get outside of that industry, I have found that using three categories instead of two helps leaders identify their weak spots and focus their improvement efforts. Those three categories are dropped objects from Elevated Work, Elevated Equipment, and Material Movement. Let me first describe the categories, then make the case for the new scheme.

The “Dropped Object Prevention Scheme Recommended Practice” published by DROPS Online defines Static and Dynamic dropped objects as:

• Static: “Any Dropped Object whose failure may be attributed to gravitational or natural forces (i.e., without an applied force, unsecured items, or failure of fixings).”
• Dynamic: “Any Dropped Object whose failure may be attributed to applied forces (e.g., from the impact of equipment, machinery or other moving items, severe weather, helicopter downdraft, manual handling etc).”

Alternatively, I like to categorize dropped objects as those from:

• Elevated Work: Dropped Objects that originate from activities of workers, such as scaffolding, maintenance, and operations.
• Elevated Equipment: Dropped Objects that originate from elevated equipment with no direct involvement of workers, such as light fixtures, ceiling tiles, windsocks, and valve handles.
• Material Movement: Dropped Objects that originate from transfer of materials from one location to another, such as from cranes, gin wheels, hand-carrying, trucks, and forklifts.

For the most part, the Static category maps to Elevated Equipment, and Dynamic has been broken into two categories, Elevated Work and Material Movement. So, why are these categories more useful in broader businesses?

First, they barely need definitions. They are simple descriptions of the source of the dropped object. Over the years, some of my colleagues and I have struggled with the definitions of Static and Dynamic. If a maintenance technician kicks a left-behind nut down the stairwell as he turns around to grab a wrench, is it a Static or Dynamic dropped object? It was an unsecured item (Static), but it fell because of an applied force, the kick (Dynamic). I have seen such scenarios categorized both ways. In the proposed scheme, it clearly fits in the Elevated Work category.?

More importantly, the Dynamic category of dropped objects is very broad. If you use the definition literally, it includes everything from a pipe fitter losing control of his wrench to a gust of wind knocking a loose sun visor off a camera to a drum falling off of a pallet when the forklift hits a pothole. These incidents have different causes; different controls will prevent them. The three categories presented here are more aligned with the controls. Hence, you can diagnose your problem more specifically and target your improvement efforts. Even if you are struggling with all three equally, I think it is best to focus on one at a time so you can improve quickly and sustainably.

Static and Dynamic have served the Drilling industry well. They were based on the specific exposures in their operations. During drilling operations, there are a modest number of people (tens, not thousands) working at height on most days . But during a big construction project or a turnaround at a refinery, thousands of people can cause dropped objects while working at elevation every day. For those levels of exposure, dropped objects from Elevated Work deserve their own category.?

The controls for dropped objects from Elevated Work are very different from other types of Dynamic dropped objects. Let’s compare dropping a large stud while removing a blind flange to a trolley hoist falling off its supporting beam. To prevent the stud from falling, I would expect the work crew to keep it in a closed container until needed and then cover all possible pathways to lower levels with tarps, netting, boards, or similar. And of course, barricade the area below, just in case the other controls fail. In other words, the pipe fitter should assess the risk and implement the controls himself for a short time. To prevent the trolley hoist from falling, engineers and inspectors must ensure it is designed and installed correctly, and then it must be inspected and maintained as long as it is in place. Very different solutions!

I am not advocating the Drilling industry change their ways. They have been very successful in reducing dropped objects over the last decade and have flattened the learning curve for everyone else. Rather, I am advocating the three types described here are better suited for most other settings in which dropped objects occur. Whichever you choose to use, focus on the causes and controls, and you will improve!

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