Posted July 4, 2018

ANSI approves publication of Dropped Object Prevention Standard

New standard will have wide-ranging impact on job site work practices.

by Nick Voss

ANSI, the American National Standards Institute, has approved the publication of a new standard address the need for dropped object prevention and tool tethering. Approved as of July 2nd, 208 and formally known as, ANSI/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, over 52,000 “struck by falling object” OSHA recordable incidents occur every year in the US alone. In 2015 the BLS reports 247 fatalities from being struck by a falling object, accounting for 5% of all workplace fatalities.

Most contractors rely on catching the falling object (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 doesn’t address the real root cause and so the risk of injury or worse is always present.

The only way to reduce the chance of injury or harm to 0% is to prevent the uncontrolled fall in the 1st place.

Objects dropped from 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 PPE struck by it below will most likely only suffer a slight injury treatable with just 1st aid. Drop that same tape measure off the 17th floor of a building, and it will carry enough energy to defeat any PPE, and even causing a fatality. A 2-pound wrench can be deadly from the 4th floor, and a standard power tool such as a drill can be serious from lower still.

A Ground Breaking Standard

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 Object Prevention (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 us safer and what is dynamic drop testing anyway? Let’s see if we can shine a light on some of these questions.

Up until then, Dropped Object Prevention companies have 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 determine the impact force that object will have when it is suddenly stopped by either the tether or the ground (hopefully the ground and not a person below).

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 static (not moving) 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 1 problem with static testing. Static testing 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 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 and that’s bad 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 perfect align during the test, the device must still fight off gravity and prevent a drop and that is something you just can’t simulate with a static test.

If it was you standing below someone working at height, how would you want their tethers tested? If it was me I’d be sure to ask my DOP supplier to produce their dynamic drop testing certificate before I’d let my teams work at height.

For More Information

For More information, visit and check out our START Work Program designed for DOP.

  • Learn how to deploy Dropped Object Prevention where you work with our revolutionary START Work DOP Best Practices (free to download).
  • Up to date news on the new ANSI/ISEA 121 standard for Tool Tethering and other news on standards and regulations.
  • DOP Connect shared learnings and insights in working at height and tool tethering.
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Nick Voss is Director of Product Management  for KeyBak Pro. Email him at Visit