Fall protection planning must consider the different types of work that will be taking place at heights.
Not every fall hazard is created equal. And that’s certainly true of leading edges.
Many construction jobs put workers at a risk of falling. But leading edge work is a specific scenario that involves its own standards and guidelines. The safety measures used for other types of fall hazards are typically not sufficient or practicable for leading edges.
If that sounds intimidating, don’t worry. We’ll clear all that up in this article.
We’ll start by explaing exactly what leading edges are and which regulations apply to them. Then, we’ll go over the measures you can implement to ensure that leading edge work is done safely and in compliance with safety regulations.
What Is Leading Edge Safety?
OSHA 1926.751 defines a leading edge as:
“the unprotected side and edge of a floor, roof, or formwork for a floor or other walking/working surface (such as deck) which changes location as additional floor, roof, decking or formwork sections are placed, formed or constructed.”
Basically, a leading edge is the unprotected edge of a surface that is actively being worked on. This means that the edge itself advances, changing location and shape as the work proceeds.
Those edges are also where the work is taking place, as the leading edge itself is under construction. There’s no way for workers to simply keep their distance from the edge because they have to work on it.
Being so close to a fall hazard obviously heightens the risk of falling. But there are two other considerations that make fall protection challenging for leading edge work:
- Finding overhead anchorage is often impossible
- The leading edges are often sharp and could cut or damage fall protection lifelines
OSHA Standards for Leading Edges
OSHA’s Subpart M covers the requirements for construction worksites to provide fall protection.
It applies to situations in which a worker is 6 feet or higher above a lower level to which a fall is possible. This includes, of course, leading edges.
The leading edge rules apply whether the worker is working on the leading edge or just working in an area where a leading edge fall hazard is present.
1926.501(b)(2) calls for protection via a guardrail, safety net, or personal fall arrest system (PFAS) where those solutions are practicable and can be installed to meet requirements. If the employer can demonstrate that the use of such systems creates a greater hazard or is otherwise unfeasible, they must develop a Fall Protection Plan, satisfying the requirements of 1926.502(k).
Under 1926.502(k), the fall protection plan is:
- Only applicable in leading edge work, precast concrete erection work, and residential construction work
- Only an option if it can be demonstrated that conventional fall protection measures (guardrails, nets, and PFAS) cannot be implemented
In such cases, the plan must explain the fall protection methods that will be used in absence of the conventional ones, such as scaffolds, ladders, or vehicle mounted surfaces.
Any zone that contains these fall hazards must have controlled access, meaning that only a specific list of designated employees are authorized to access it. Anyone not on the list is prohibited from entering the area.
ANSI Standards for Leading Edges
The ANSI Z359.14 standard covers testing and design requirements for self-retracting devices (SRDs). The original release of the standard included the following types:
- Self-Retracting Lifelines (SRL)
- Self-Retracting Lifelines for Leading Edge (SRL-LE)
- Self-Retracting Lifelines for Rescue (SRL-R)
In 2021, the standard was revised to add “Self-Retracting Lifeline, Personal,” a device compact enough to be attached to the harness itself as opposed to being positioned at the anchorage end of the PFAS. Under the revised scheme, SRL-LE devices have been reclassified as Class 2 devices. Class 1 devices are not rated for leading edge work and are only suitable for use with overhead anchorage.
Class 2 Self-Retracting Lifelines
The lifeline of a Class 2 device has to include an integral shock absorbing device such as a shockpack on the end of the lifeline that is connected to the user’s harness.
Although the physics may appear the same whether the energy absorber is attached at the terminal end or the anchor end, there are important differences. In a fall from a leading edge, the edge can kink or otherwise hang up a lifeline in such a way that the absorber won’t deploy and thus cannot lessen the arrest force to the legislated maximum of 1,800 pounds. Worse yet, the line could snap when pulled with too great a force across the sharp leading edge.
The shockpack is essential for leading edge applications. Any self-retracting device that lacks one is inappropriate for this type of work. The shock absorber lessens both the arrest force on the falling body and the tension on the line, ensuring that the PFAS can work as designed.
Testing
Z359.14 lays out testing requirements for SRD components down to minute details like the permitted sharpness of the edge used in drop testing. The requirement is that the radius of the edge is no greater than five thousandths of an inch, making for a very sharp corner that likely exceeds the sharpness of any of the actual leading edges found on a worksite.
This is important because all of the components must be tested against worst-case-scenario conditions to make sure they will perform adequately under real-world conditions. Equipment rated for leading edge applications must be robust enough to keep its integrity no matter what type of leading edge is involved.
Tests for SRDs include a dynamic performance drop test, which requires a fall over a test edge of the required sharpness with:
- A weight of 282 pounds attached
- An additional 675 pounds of weight added to the line
- A swinging period of 10 seconds
Leading Edges and Protective Equipment
As with any hazard, the hierarchy of controls applies to leading edge work. Engineering controls are preferred to administrative controls and PPE because they are more effective at preventing incidents.
Guardrails
A guardrail is the preferred solution in most cases; however, due to the nature of a leading edge, they are often impractical. A stationary guardrail would interfere with work being done or obstruct access to the work surface, thus encouraging workers to circumvent the barrier entirely, potentially increasing their risk of falling.
Where they can be used, guardrails have a number of design, construction and performance requirements. Specifically, guardrails must have:
- A top rail that is 39 – 45 inches above the walking-working level
- When stilts are used, the top rail must account for the added height
- An intermediate rail installed midway between the working surface and the top rail (unless there is a parapet wall 21 inches or higher)
- No opening greater than 19 inches (any wider expanse may need balusters or other intermediate vertical posts)
Safety Nets
Where safety nets are used, they must be installed no more than 30 feet below the working surface and installed as close as possible. There are guidelines for how far the outer edge of the net is allowed to be from the leading edge, depending on how far the drop is.
All nets must be drop tested to confirm their strength and to ensure that the material construction and the connections can withstand the force of a fall from the height of the working surface.
Personal Fall Arrest System (PFAS)
Although they come in many configurations, a personal fall arrest system generally consists of three elements:
- Harness (worn on the body)
- Anchorage (a secure connection point on the jobsite)
- Lanyard or lifeline (which connects the harness to the anchorage)
Leading edge scenarios have implications when setting up a PFAS, mainly for the anchorage location and type of lifeline used. Self-retracting lifelines (the type that plays out line and retracts it back depending on the distance of the worker to the anchorage) are commonly used in leading edge setups. The equipment must be rated for leading edge use specifically, because the edge itself and surface-level anchorage create the potential to sever the line, which would prevent the fall from being arrested.
When using an SRL, the anchorage should ideally be set back from where the work is being done, rather than attaching right at the workers’ feet. Ideally, at least 5 feet from the leading edge. This allows the device’s pawl mechanism to engage and the fall to arrest with a shorter free fall, thus limiting the arresting force on the falling body. If the anchorage is right at the leading edge, the device will only activate after the D-ring is below the device, thereby increasing the free fall distance.
However, setting the anchor point too far behind the worker makes another undesirable scenario possible. If the worker falls after playing out a lot of the line and moving in an off-perpendicular direction from the anchor, the result will be a long swing in which the line runs along the sharp leading edge under tension, potentially sawing through the line. Even if the line holds, such a large swing could still result in severe injury or death.
Certain scenarios may allow for a travel restraint system instead of a fall arrest system. This type of system prevents a worker from reaching the edge at all. In order to work effectively on a leading edge, the anchorage might have to be frequently adjusted. This can make it cumbersome approach, but it might still be suitable for some situations.
Leading Edge Safety
Planning
Leading edges don’t show up by surprise. Work schedules and coordination should reveal where and when leading edge safety needs to be considered.
Whenever leading edges are under construction, they should be accompanied by fall protection planning that includes:
- Hazard identification
- Hazard controls
- Training requirements
- Inspection procedures
- Use, care, and maintenance of fall protection equipment
Training
Typically, anyone working at heights will require training. Those working at heights on a leading edge should also be trained in the specifics of that work, including the equipment and anchorage requirements, which differ from conventional fall protection.
Those in charge of supervising and implementing controls also need adequate training to oversee the fall protection strategies.
Equipment
All equipment used in leading edge fall protection must conform to standard strength and design requirements, and be used and maintained in the manner described by the manufacturer. Fall protection used in leading edge work must be Class 2 or SRL-LE rated, anything less may fail under the fall conditions. Class 2 devices can also be used in ordinary fall protection since they are rated to a higher standard.
Equipment must be inspected before each use and certified on a periodic basis (as specified by the manufacturer).
Once it has been involved in a fall, the equipment may not be used again unless it can be recertified for use by a qualified party.
Conclusion
Fall protection planning is difficult to implement effectively, and leading edge scenarios add a level of complexity. Given the many specific considerations involved, it is now thought of as a discrete subcategory of fall protection, complete with its own standards, guidelines, and equipment.
Despite the rigorous requirements and the ongoing development of standards, falls are still a leading cause of injuries and fatalities in construction. We owe every worker the careful, thoughtful consideration it takes to make sure current best practices are in place to keep them safe at the leading edge.
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