A few years ago, a young man was dismantling a scaffold in a petrochemical plant in Houston. As required by his company, he wore a personal fall arrest system (i.e., a harness and lanyard). He was tied off to a component of the scaffold he was dismantling. Suddenly, something went terribly wrong. The scaffold anchorage point to which he was tied off failed. Instead of falling 6 feet and having a shock absorbing lanyard engage, he fell almost 40 feet to his death.
That same year, another young man was erecting a tall scaffold at another petrochemical plant a few miles away. He also wore a personal fall arrest system tied off to the scaffold. He also fell. This time, the anchorage point did not fail. The young man fell the 6 feet that the lanyard allowed, plus the distance of elongation and deceleration of the shock absorption system, and his fall was arrested. He climbed onto the scaffold platform two levels down. While he was obviously shaken, he was not injured. His life was probably saved by the personal fall arrest system he used while erecting scaffolding.
These two true incidents introduce the complexity of the problem of providing fall protection for scaffold erectors. This article focuses on OSHA regulations, points to consider about using the scaffold as an anchorage point, and practical aspects of tying off to various types of scaffolds. However, this article will not give a one-size-fits-all solution to the issue of fall protection for scaffold erectors, because such a solution does not exist.
What Are the Regulations?
First, let's look at applicable OSHA regulations. In the OSHA 1926 scaffold standard, two regulations relate to fall protection for erectors: 1926.451(g)(2) and Non-Mandatory Appendix B. Regulation 1926.451(g)(2) states:
"1926.451(g)(2): Effective Sept. 2, 1997, the employer shall have a competent person determine the feasibility and safety of providing fall protection for employees erecting or dismantling supported scaffolds. Employers are required to provide fall protection for employees erecting or dismantling supported scaffolds where the installation and use of such protection is feasible and does not create a greater hazard."
This regulation makes it clear that fall protection should be provided if it is feasible and does not create a greater hazard.
But when is fall protection feasible? To answer that question, OSHA set aside Non-Mandatory Appendix B, titled "Criteria for Determining the Feasibility of Providing Safe Access and Fall Protection for Scaffold Erectors and Dismantlers." OSHA intended for this appendix to be published within a few months of the effective date of the regulation in 1996. Unfortunately, the issue is so complicated that OSHA has been unable to develop Non-Mandatory Appendix B. We will discuss why it is so complicated later in this article.
In the meantime, OSHA sent a directive to its field offices that compliance officers must send any intended citations based on 1926.451(g)(2) to the Washington, D.C., office for review before the citation can be issued. This has had the effect that most compliance officers are not actively writing citations based on 1926.451(g)(2) until more clarification is in effect. Consequently, 1926.451(g)(2) is still an enforceable regulation if a compliance officer chooses to pursue it, even though Non-Mandatory Appendix B has not been developed.
Why can't we simply tell our erectors to wear a personal fall arrest system, tie off 100 percent of the time, and say that we've solved the problem? The answer is that there is more involved in having a proper personal fall arrest system in place than simply putting on a harness and tying off to something.
This leads us across regulations from Subpart L (i.e., the scaffold subpart) to Subpart M (i.e., the fall protection subpart). Subpart M covers the performance criteria, installation and use of personal fall arrest systems. There are a couple of regulations in Subpart M, specifically in 1926.502(d), which go to the heart of this issue.
Regulation 1926.502(d)(15) reads:
"Anchorages used for attachment of personal fall arrest equipment shall be independent of any anchorage being used to support or suspend platforms and capable of supporting at least 5,000 pounds (22.2 kg) per employee attached, or shall be designed, installed and used as follows:
(i) as part of a complete personal fall arrest system which maintains a safety factor of at least two; and
(ii) under the supervision of a qualified person."
Thus, the anchorage point to which we tie must meet the requirements listed above. Let's look at a couple of examples.
We will assume that an erector working 50 feet above ground in a stationary position has an I-beam or similar structural member just above his head to which to tie off. Using the proper attachment equipment, he secures his lanyard to the I-beam. In this example, it is feasible and mandatory to provide fall protection. Unfortunately, this will not be the case most of the time.
Using the same example, assume that the I-beam does not exist. What if the only thing to tie off to is the scaffold?
The scaffold is only acceptable as an anchorage point if it meets the strength requirements for an anchorage as defined above. Does a scaffold meet the requirements of 1926.502(d)(15)? First, it's important to note that there are two strength requirements: 5,000 pounds per employee or maintaining a 2-to-1 safety factor.
What does this 2-to-1 safety factor mean? Assume that the manufacturer of the personal fall arrest system being used guarantees that, when properly employed with the shock absorber, the system will limit the impact force to 1,800 pounds. If the anchorage point holds 3,600 pounds, it maintains a 2-to-1 safety factor. Thus, the qualified person may use performance criteria from the manufacturer to lower the strength requirement of the anchorage point, as long as the anchorage holds twice the potential impact.
Using Scaffolds for Anchorage
OSHA has asked NIOSH to conduct a study of the use of scaffolds as anchorage points. As part of this study, NIOSH had a meeting in 1998 of interested parties throughout the United States. The object was to list the various items that could affect the scaffold when it is used as an anchorage point. Hundreds of items were listed, such as the configuration of the scaffold, the diameter of the tube, wall thickness of the tube, type and strength of steel, location of the impact on the tube (i.e., mid-span or close to the connector), tying of scaffold to a structure, distance of fall and pendulum effect of fall.
A related topic is the effect of using the scaffold as an anchorage point on the rest of the scaffold. That is, if the impact force of a fall causes the scaffold component to break, how will that affect the rest of the scaffold? Scaffold regulations require that safety factors must be maintained on the scaffold itself, not just the fall protection system.
When the NIOSH study is completed, we hope to have a better database.
While, thus far, some drop tests have been conducted and videotaped, no true scientific study has been done by a certified testing lab.
An important factor to remember is that scaffold tubing is hollow and is made from small-gauge steel or aluminum. To see what I mean, hold up the end of a frame leg and look at the end.
A properly constructed scaffold will carry thousands of pounds, but the weight must be uniformly spread over the bearers and transferred to the ground through the legs over the axis of the tube. The tubing is not very strong when point loads (that is, loads that concentrate on one point, like a karate chop) are involved.
We have seen karate masters break 2-by-4-foot lumber with a karate chop to mid-span. I have never seen anyone stand the 2-by-4 upright and try to deliver a karate chop down through its axis. A 2-by-4 is very strong when the load is imposed down its axis. The same is true with scaffold tubing. It may hold thousands of pounds when the load is applied along its axis, but it can be very weak when a point load occurs at mid-span.
Many manufacturers publish both uniform and mid-span point loading data for bearer tubes, and it is shocking how small the mid-span point load limits are. Unfortunately, if an erector is tied off to the scaffold and a fall occurs, it is exactly that type of karate-chop point load, not a uniform load, that is imposed.
For these reasons and many others, most manufacturers of scaffolding have issued warnings that the scaffold itself does not meet requirements for a proper anchorage point. That does not mean that a scaffold component can never meet the strength requirements of 502(d)(15). It would be as inaccurate to say that as to say that it always does.
Another regulation that comes into play is 1926.451(d)(16), which reads:
"Personal fall arrest systems, when stopping a fall, shall:
(i) limit maximum arresting force on an employee to 900 pounds (4 kg) when used with a body belt;
(ii) limit maximum arresting force on an employee to 1,800 pounds (8 kg) when used with a body harness;
(iii) be rigged such that an employee can neither free fall more than 6 feet (1.8 m), nor contact any lower level;
(iv) bring an employee to a complete stop and limit maximum deceleration distance an employee travels to 3.5 feet (1.07 m); and
(v) have sufficient strength to withstand twice the potential impact energy of an employee free falling a distance of 6 feet (1.8 m), or the free fall distance permitted by the system, whichever is less."
Notice that 1926.502(d)(16)(iii) limits the free-fall distance to a maximum of 6 feet. This means that when the common 6-foot lanyard is used, the anchorage point must be at the height of the D-ring or higher. For example, if the erector ties off at his feet, he will fall the height from the D-ring to his feet (approximately 5 feet), then the 6 feet of the lanyard, for a total of 11 feet of free-fall before the shock absorber engages. This exceeds the maximu- allowable free-fall.
Why is this important? The farther a weight free-falls, the faster it will be going upon impact, and the higher will be the impact force. Most personal fall protection systems are designed to function properly when the free-fall is limited to 6 feet, as required by regulations. If the free-fall is twice that distance, they may not function properly.
When the erector is standing on the top level putting the scaffold together, there is almost never a scaffold structural member at shoulder height or above. The closest scaffold component may be the one at his feet. There is a substantial difference between types of scaffolds with respect to what components, if any, extend up above foot level. In the most common type, frame scaffolding, no component extends up. By comparison, with tube-and-clamp or system-type scaffolding, some posts may extend up above foot level, depending upon the configuration, level and height of the posts used.
In many cases, by the time the erector has assembled that level to the point that scaffold structural members are in place at shoulder height or above, it is time to move up to the next level.
It may be possible for erectors on lower levels to tie off above the D-ring because the scaffold is completed above them. Often, however, these erectors are already standing inside the cross braces or horizontal hand rails, if that level was completed. But, for the erector on top, finding a scaffold component that meets the strength requirements of 502(d)(15) and the height requirement of 502(d)(16)(iii) will be impossible to meet in most cases.
I often have heard people comment, "It is better to be tied off to something than nothing at all. At least you have a chance if you fall." I don't necessarily disagree with that statement.
Let's assume you are erecting a scaffold and the only anchorage available is a scaffold component that the manufacturer has warned is not rated for an anchorage point. Remember that just because a component is not rated on paper to carry the impact forces and maintain all the safety factors does not mean that the component will fail in every situation. For example, if you are tied off to the mid-span of a 7-foot-long system scaffold handrail, that tube is not rated for the point load imposed by a fall. That does not automatically mean that the tube will break in two. It might bend beyond allowable deflection limits, it might kink, it might pull the adjacent posts to which it is secured in toward the impact, but unless the tube breaks in two, it will "work" in the sense that it arrests the fall and prevents the erector from falling to the ground. I have seen many cases in which scaffold tubing was overloaded and bowed, but did not break, such as when a crane inadvertently drops a load of scaffold tubes weighing several hundred pounds the last couple of feet onto a handrail.
Thus, while the scaffold may not meet all anchorage requirements, many companies have their erectors tie off to the scaffold if no other anchorage is available. If that is your intention, consider these points:
- The scaffold post (as opposed to a horizontal member) is the strongest component because the impact force will be imposed down its axis.
- The method of connecting the lanyard to the scaffold tube is important. Several types of connectors are available. Those that have wider straps spread the load out over more surface area than steel caribiners. Wide webbing strap-type chokers also have more "give" than steel and will cause less damage to the tubing.
- On lightweight freestanding towers, the impact force may pull the scaffold over, particularly on aluminum towers. The scaffold should be tied back to prevent tipping. In certain cases, it may create a greater hazard trying to tie off than not. For example, sometimes the material must be hoisted up at one end of the scaffold, then carried to the other end by the erector on top. A worker might be required to walk 50 to 100 feet on top of the scaffold while carrying a scaffold frame, 16-foot-long plank or other load. In my opinion, making the erector stop to untie, then retie his lanyard to the frame at his feet every 7 feet horizontally, while he carries the load, is a case of creating a greater hazard while trying to eliminate the first. However, if he can tie off one time to a horizontal trolley line, then walk to the other end without untying, then it is feasible.
- There are differences in strengths of tubing between different types and brands of scaffold products. For example, I feel confident tying off to the post of domestic system scaffold. I would not have much confidence in tying off to the mid-span of a conventional frame scaffold guardrail.
- The height above ground or other obstructions must be considered. Suppose you are building a freestanding frame tower. You are standing on top of the second 6-foot, 6-inch-high frame, approximately 13 feet high. You tie off to the top of the second frame, at your feet. You're 6 feet tall and the lanyard is 6 feet long, for a total of 12 feet. The anchorage is 13 feet from the ground. If you fall, your feet will hit the ground before the shock absorber fully engages. Then watch out for the falling scaffold!
- Tying off can save your life, even if the system does not work. Look at the previous example. Assume the individual fell because he tripped or slipped. As a result, he falls, head-first. When his head reaches the end of the lanyard, about 6 feet from the top of the scaffold, the lanyard should catch and engage the shock absorber. At this point, his feet should start to swing around and may cause him to strike feet-first, instead of head-first. While there was not enough height allowed for proper elongation and deceleration, the fact that he did not hit, head-first, may have saved his life.
- The working environment plays a big role. In petrochemical and power plants, scaffolds tend to be only a few feet long, but they are taller than they are long. They are built from system scaffolding, in which posts extend above the erectors' foot level. It is easy to have the erectors tie off to the post extension while on the scaffold, allowing them to reach all necessary surfaces without untying and retying.
- By contrast, commercial buildings may require scaffolds that are several hundred feet long and made of frame scaffolding. The erector may need to traverse the length of the scaffold carrying equipment without having a post extension available to which he can tie.
- The mental focus of the erector, compared with the scaffold user, is important. For example, I recently erected scaffolding around portions of my house so I could replace rotten wood and repaint the exterior. While I was pulling nails, cutting lumber, painting and caulking, it was important that I have a safe scaffold because my attention was focused on the job at hand. If I had not had full planking or guardrails, I could easily have stepped through an opening and fallen. When I was erecting or dismantling the scaffold, however, my attention was focused on the specific task involved, such as setting the frame on the pins and attaching the cross braces. I knew I was exposed to a fall hazard during this activity, but my training and experience taught me exactly what I could or could not do safely, and I concentrated completely on that task. I believe my work practices were completely safe, even though I did not use a personal fall arrest system, because it was not feasible in that situation.
The whole issue of fall protection for scaffold erectors is far more complicated than most folks expect it to be. To say that fall protection is always feasible or to say that it never creates a greater hazard to use it is inaccurate. Similarly, assuming that tying off 100 percent of the time means that you have a legal fall protection system 100 percent of the time is inaccurate.
Providing a fall protection system for erectors that meets the letter of the law is impossible in many situations. Using the scaffold as an anchorage point may not meet all legal requirements, but many safety people believe that, if no other anchorage is available, it is safer for the erector to tie off to the scaffold than to not tie off at all. In some cases, however, asking the erector to tie off 100 percent of the time creates a greater hazard than not providing fall protection, particularly where horizontal movement is mandatory.
Finally, all erectors should be trained in the applicable regulations and should consult their company safety director for guidance on this issue.
John A. Palmer, director of the Scaffold Training Institute, has worked as an erector, foreman, estimator, manager and owner of scaffolding companies specializing in large projects. He devotes full time to scaffolding training and has written manuals, developed video and CBT programs, and has spoken before ASSE, NSC, AGC and other industry organizations. He served on the board of directors of the Scaffolding Industry Association.