Ontario, California (July 2, 2018)—The American National Standards Institute (ANSI) has approved the publication of a new standard address the need for dropped object prevention and tool tethering, formerly know as ANSI/International Safety Equipment Association (ISEA) 121-2018: American National Standard for Dropped Object Prevention Solutions. This standard addresses the real need for reducing workplace accidents, injuries and deaths due to falling objects.
What is dropped object prevention?—Dropped or falling objects from height present a significant safety hazard in many industries around the world today, and the numbers are staggering. According to the Bureau of Labor Statistics (BLS), over 52,000 “struck by falling object” Occupational Safety and Health Administration (OSHA)-recordable incidents occur every year in the United States alone. In 2015, the BLS reported 247 fatalities due to workers being struck by a falling object, accounting for five percent of all workplace fatalities.
Most contractors rely on catching the falling object (with netting, toe boards, etc.) or erect temporary structures to shield people on the ground in the event of the inevitable drop. While this does help reduce the number of actual injuries caused by falling objects, it does not address the root cause and so the risk of injury or even death is always present. The only way to reduce the chance of injury or harm to zero percent is to prevent the uncontrolled fall in the first place.
Objects dropped from a significant height strike the ground with incredible force. Take a simple tape measure weighing in at just 0.5 pounds: If it was dropped from a height of 10 feet, someone wearing personal protective equipment (PPE) struck by it below would most likely only suffer a slight injury, treatable with just one staid. However, if that same tape measure were dropped off the seventeenth floor of a building, it would carry enough energy to defeat any PPE, and possibily even cause a fatality. A 2 pound-wrench can be deadly from the fourth floor, and a standard power tool, such as a drill can be serious from an even lower height.
Why is the new standard ground-breaking?—The new standard is ground breaking, requiring dropped object prevention solutions to undergo dynamic drop testing to be considered fit for use. Why is dynamic drop testing important when it comes to tool safety? When the ISEA 121 committee on dropped objectpPrevention (DOP) began working on the new standard, they made a keystone decision to require dynamic drop testing to prove all DOP solutions instead of the traditional static testing. But why is this important? How does this make workers safer, and what is dynamic drop testing anyway? Let’s see if we can shine a light on some of these questions.
Prior to the standard, DPO prevention companies tested their products the same way rock climbing companies test their rope and carabiners—they used a math equation and a static tensile test. To follow this method, you take the mass you’re going to drop, use physics to determine the velocity it will be traveling at the full extension of the tether (aka lanyard), and from that number, determine the impact force that object will have when it is suddenly stopped by either the tether or the ground. This force is many magnitudes higher than the just the simple mass of whatever was dropped. A 10-pound weight dropped 120 inches has an impact force of 460 pounds. To test the DOP device, a lab attaches it on a unmoving tensile testing rig and pulls or stretches it from both sides. The lab increases the force on the device until it breaks. If it breaks with a force higher than the minimum impact force, then it passes and is deemed safe for use. If it breaks at a force lower than the impact force, it’s back to the drawing board or to a lower weight rating. You also get nice looking graphs like this one showing the load and the displacement (how much the tether stretched) as an output of the testing.
Seems simple right, what could be better? There is one problem with static testing: It is an excellent way to determine how much force a safety device can withstand before it breaks (called load capacity) when it is pulled straight down and everything is perfectly aligned. However, in real life, objects dropped rarely fall straight down. They tend to swing, ricochet off structures and scaffolding, bounce and recoil in unpredictable ways. Want to see how violent this really is? Here is a short clip simulating a real-life drop. As in the example above, the weight is 10 pounds, dropping 120 inches.
A device may pass a static test with flying colors, but when put into a real-life situation, when the straps or cable, D-rings, carabiners, and other part are stressed and strained in ways that are not perfectly aligned by gravity, motion and dynamic force, it may still fail and break—a terribly dangerous scenario for anyone standing underneath. This is something no contractor, worker or manufacturer wants to discover on the jobsite where lives are at stake.
With a dynamic drop test, an object of known weight is dropped multiple times. If the device prevents a drop, it passes. If it breaks and the object drops, it fails. The device is still subjected to the same impact force as it would be in a static test, but with the added challenge of proving the total solution can withstand the stress and strain of swings, bounces and recoils real devices are subject to everyday. When (not if) things don’t perfectly align during the test, the device must still fight off gravity and prevent a drop—something that just can’t be simulated with a static test.
For More information, visit dropsafetyequipment.com.
