Fall clearance requirements

Responding is Dustin Hawkins, vice president of business development, FallTech, Compton, CA

The use of fall protection, including personal fall arrest systems, is increasing as employers and employees become more aware of the risks associated with falling from elevated work locations. However, in many cases, workers using a PFAS are unaware of the clearance necessary to avoid contact with a lower level during a fall. In particular, this is true when workers choose to attach their PFAS to anchorages that are below the back D-ring of their full-body harness.

OSHA requires most free falls to be limited to 6 feet or less, and most PFASs are designed to withstand only a 6-foot free fall. When workers attach their PFAS to an anchor that is below their back D-ring or even at their feet, the increase in fall distance results in greater forces being applied to the worker and the anchorage, and an increase in clearance distance becomes necessary to avoid hitting the next level or obstruction below.

Although OSHA may not specifically allow a free fall of greater than 6 feet, in many situations the only feasible anchorage location may be below the back D-ring of the user’s full-body harness. The ANSI Z359 committee has acknowledged this problem and is providing testing guidelines for PFAS manufacturers.

In “ANSI Z359.13 – 2013 Personal Energy Absorbers and Energy Absorbing Lanyards,” specific tests for 12-foot free-fall lanyards exist to ensure that when fall events exceed 6 feet, the lanyard and energy absorber will limit deceleration distances to 60 inches or less and keep forces well below 1,800 pounds. Although the user of this type of lanyard still needs to take care to avoid other hazards such as sharp edges and weld spatter, a properly designed and tested 12-foot free-fall lanyard provides greater certainty and predictability than a traditional fall-arrest lanyard designed only for a 6-foot free fall.

Additionally, “ANSI Z359.14 – 2014 Safety Requirements for Self-Retracting Devices (SRD) for Personal Fall Arrest and Rescue Systems” acknowledges that in some cases a SRD may not be able to be attached to an overhead anchorage and, therefore, greater free fall may occur during a fall event. Within this standard, ANSI Z359 provides testing requirements for below-back D-ring attachment of an SRD. In fact, it specifically requires that the testing be performed so the cable or web of the SRD makes contact with a sharp edge that simulates potential work environments that could cause failure of the system. This leading-edge testing also allows the manufacturer the opportunity to demonstrate to the worker what additional deceleration distances may be associated with the additional free fall.

If a worker is exposed to a fall hazard for which the only anchorage solution is below the back D-ring of their full-body harness, it is important that the correct product be used to avoid extended deceleration distances and increased forces.

Editor's note: This article represents the independent views of the author and should not be construed as a National Safety Council endorsement.