Drop Zone Management: Expanding Our View of Line of Fire
This month’s Tailgate takes a closer look at a line-of-fire issue, specifically the drop hazard created when working aloft. Unfortunately, year after year utility workers are injured when objects are inadvertently dropped from heights, creating a significant threat for those on the ground. As we continue to refine the practices in our profession, the methods traditionally used for working aloft need to be examined and possibly modified. This will bring more control and safety to those on the ground who are near the overhead work being performed.
Since the Beginning of Line Work
Anytime overhead work is performed there is a real risk of equipment, materials or tools falling from the elevated position. Traditionally we consider the area under the work position to be considered the “drop zone.” For more than 100 years, aerial lineworkers have known there is danger lurking for anyone who is under or near the elevated work position. The area under the work may be known as the “pocket,” “the hole” or a unique name used by you and your co-workers, but it’s widely known across the nation that this is an area of concern for anyone on the ground.
It’s All About the Physics
Any object dropped from a height creates a significant amount of force. The higher the aerial work being performed, the more force the dropped object will generate. For example, a 2-pound ceramic insulator dropped from 30 feet creates about 6,000 pounds of force. Now consider that a 180-pound professional boxer throws a punch somewhere between 1,200 to 1,800 pounds of force. That 2-pound ceramic insulator is generating two to three times more force than the boxer. That may be surprising to some people, but it’s all about the physics.
How to Manage the Drop Zone
Following are things you and your crew members can do to minimize hazards:
• Establish a clearly identified drop zone below the elevated position. This shall be discussed during the pre-job briefing, and include the zone boundaries and practices employed to control drop hazards. Practices include:
o Keeping the zone clear of workers while work is occurring overhead
o Stopping overhead activities and ensuring all material is positively under control if there is an unavoidable need for a crew member to enter the zone
o Exercising positive controls anytime tools or materials are being moved from the ground or bucket. Tool bags and hand lines are the only way to ensure that the tools or material will safely arrive where you need them. The 100+-year-old practice of throwing materials from the bucket to the ground needs to be challenged. This practice reinforces unsafe behavior which will only result in an injury over time – guaranteed.
o Situation awareness and good verbal and visual communication with those aloft to ensure crew members below are clear of potential injury threats.
• Consider using new techniques or equipment to prevent tools, materials and other objects from falling. For critical locations – such as crowded pedestrian sidewalks and under-built construction sites – use positive means to control tools, equipment and materials. Tool lanyards, a leash from tool to wrist or other secured location, are becoming more popular in other industries and can easily be adapted for aerial work.
• Consider the extended drop zone, the area beyond the typical inverted cone shape often thought of as the drop zone. Under-built facilities and other obstructions can cause a dropped object to deflect and fall outside the perceived drop zone. The distance the object can travel is greatly underestimated by crews and has resulted in some very serious injuries.
By taking the precautions described in this Tailgate, you can increase your job site safety significantly and ensure that you and your crew will go home day in and day out without injury.
About the Author: John Boyle is Vice President of Safety and Quality for INTREN, an electric, gas and telecommunication construction company based in Union, Ill. Boyle has more than 27 years of experience, and has worked in nuclear and wind power generation and electric and gas distribution.