What Is a Leading-Edge?

A self-retracting lanyard (SRL) is much like a sophisticated seatbelt. When used as intended, it stops the fall or controls the impact experienced by the wearer in the event of a fall, which is why overhead fall arresters have long been used to harness workers to help prevent stability hazards. However, in a classic case of needing a product for another use, the construction industry started using self-retractable lifelines, not just in an overhead manner, but also in a horizontal one. It became so commonplace that the retractable personal protective equipment (PPE) device used in a horizontal direction gained its own term: leading-edge application.

Leading-Edge vs. Sharp-Edge

A leading-edge application involves anchoring an SRL below the back D-ring of the harness to prevent the wearer from falling over a sharp edge, which is any unrounded edge on the jobsite with the potential to make contact with the SRL. The SRL can be overhead (vertical) or at foot level (horizontal). It is important to note, however, that the combination of a leading-edge application and a sharp edge means there is the potential for a worker’s lifeline to be cut in the event of a fall. 

Thus, the risk for falls and the resulting need for leading-edge protection exists whenever workers are performing the following and other construction-related tasks:

• Aerial lift work
• Concrete decking
• Glass installation
• Precast bridge assembly
• Roof decking
• Steel erection

Falls & Hazards

Take for instance, installing metal decking on a steel-frame building. This is one of the ironworker’s most dangerous tasks because it requires the worker to spread metal sheets over narrow structural beams to form the building’s flooring. Within this dangerous task, exists the possibility of the ironworker falling off the unprotected sides of the work zone’s leading-edge, or falling off the building, should there be a structural collapse. 

According to the U.S. Bureau of Labor Statistics, ironworkers die from falls at a rate 10 times higher than the average construction worker. If a worker falls during a leading-edge application and the SRL comes into contact with the sharp edge, the lifeline could fray or be completely severed. That, in turn, could lead to injury, incident or even death. Because the overhead SRL was not designed originally for horizontal use, the industry had to make attempts to prevent sharp-edge hazards by developing energy absorbers, specific to leading-edge applications, and by protecting edges and elevating anchor points.

Dynamic Testing

The voluntary consensus standards for protection against falls from heights through American National Standards Institute (ANSI)/American Society of Safety Engineers (ASSE) Z359.14-2014 (Safety Requirements for Self-Retracting Devices for Personal Fall Arrest & Rescue Systems), found, through testing and analyses, that products not specifically designed for foot-level tie off—the type of anchoring most often used in these applications—can generate forces that may result in the retractable lanyard being cut. 

According to ANSI Z359.14-2012, “the line constituent of SRL-LEs shall include an integral energy absorber element adjacent to the end of the line which connects to the body support.” Tim Bissett, member of the ANSI Z359 Fall Protection Committee, says that in order for an SRL to be labeled “LE” for leading-edge, it must meet the standard requirements for dynamic performance, dynamic strength, static strength, retraction tension and corrosion protection, as well as the following:

• Leading-edge dynamic performance tests must be carried out with the retractable lanyard perpendicular and laterally offset to the edge, using a 282-pound rigid steel test mass falling through 5 feet.
• Dynamic strength tests must be performed with the retractable lanyard perpendicular and laterally offset to the edge using a 300-pound rigid steel test mass.
• Dynamic tests must be carried out on a 3/8-inch by 3-inch steel bar with an edge radius of 0.005 inches, or 0.13 millimeters, in accordance with American Society for Testing and Materials (ASTM) A108.
• Tests must be carried out for horizontal use and falls over a steel edge without burrs.
• The material used for the edge test must be a 3/8-inch by 3-inch or larger 1018 cold-finished steel bar.

3 Practical Safety Tips

In addition to ensuring that your workers’ fall protection equipment is tested and marked to the ANSI Z359.14 standard for SRL-LE, the following are three tips for worker safety in leading-edge and sharp-edge applications.

1. Make the edge “off limits” to the worker—Preventing a fall is always the first priority, so do not allow workers to get too close to the edge. Prohibit the work practice of walking along an edge and relying solely on the fall protection PPE. Instead, limit the workers’ access to the edge when and where possible.
2. Guard the edge and protect the retractable line—Employ control measures to prevent contact with sharp edges of all types, from wood to concrete to metal sheeting, especially if the PPE device allows the worker to cover the edge. Choose a robust line that is not only certified, but also meets the ANSI Z359 standard.
3. Train workers on the proper usage of the PPE—The Occupational Safety and Health Administration (OSHA) requires that “employees receive training in the proper use, care and maintenance of personal protection equipment (PPE) to reduce injuries and illnesses and prevent fatalities.” Although it sounds obvious, thorough worker training can help mitigate misunderstanding of the SRL-LE and how to use it.