Rigid Lifeline Fall Protection Systems
Arnie Galpin is the engineering manager with SPANCO, Inc., a provider of rigid lifeline fall protection systems. In this interview, Galpin explains how rigid lifelines work and outlines their applications and benefits.
Please provide a brief description of your professional background and of your position as engineering manager with SPANCO, Inc.
I have been fortunate enough to spend more than 25 years developing safety systems that comply with OSHA, ANSI and European Machinery Directives. Since joining SPANCO about six years ago, my role has been to develop the next generation of fall arrest systems used in horizontal lifeline applications. These new products are exciting to work with because the benefits for the SH&E professional and the worker at height are far beyond anything commonly available on the market today.
I have also had the opportunity to assist the ANSI community with standards development in different fields, such as the ANSI/ASSE Z359 Accredited Standards Committee (ASC) for Fall Arrest/Protection and its subcommittees. The Z359 ASC is an impressive collection of talent and one of the finest-run standards committees with which I have been associated. The fall protection community is in very good hands.
SPANCO has been in business since 1979. For the past 30 years, SPANCO has brought innovative material handling solutions to industry. About ten years ago, one of these innovations was the application of enclosed track (also called rigid horizontal lifeline) to fall protection. Compared to flexible horizontal systems, such as wire rope, the benefits are revolutionary. Besides arresting a worker’s fall from height, these new rigid horizontal lifeline systems provide safety benefits far above what flexible horizontal rope systems can provide.
Benefits include dramatically reduced anchorage forces, possible elimination of severe injury from secondary impacts, elimination of most swing injury hazards, virtual elimination of the potential for suspension trauma and elimination of hanger point “snags” that plague the wire rope systems. In addition, they assist in self-rescue, simplify rescue planning, eliminate confusion about total fall distance when selecting a horizontal lifeline and reduce or eliminate the potential for rollout failures.
Within SPANCO, we try to foster an open environment where our team of research and development engineers is free to dream up and test the latest and greatest solutions to the issues facing end users in the fall protection community. We then take those ideas, engineer them using finite element analysis to make them as strong as possible and make the most efficient use of high-strength steel. We then build prototypes to ensure they are easy to install under field conditions and then thoroughly test them under the harshest conditions we can think of. This guarantees that the products not only pass the requirements of ANSI and OSHA, but exceed them in every possible way.
Anybody who has ever met me knows I am all about excellence in engineering, and with SPANCO, the results of these efforts are new systems that users will enjoy using and that safety engineers will prefer to specify because of the higher level of safety, security and peace of mind these systems provide.
What is a rigid lifeline, and how does it differ from traditional horizontal lifelines?
Rigid horizontal lifelines differ from traditional horizontal flexible lifelines in that they do not flex during a fall and do not generate any horizontal pull forces on the anchorages. This has tremendous benefits in terms of increasing safety, reducing impact forces to the body, enabling self-rescue, simplifying component selection and potentially eliminating fall injuries from impacts to the body as the rope deflects downward and the worker falls downward. Rigid horizontal lifelines are also different from wide flange beams in that they are very cost-competitive with wire rope systems, come in standard configurations, are more portable and offer effortless rolling resistance.
A few companies sell rigid rail systems, but currently, we are the only manufacturer that has a full catalogue devoted specifically to standard rigid lifeline products and a distributor network across the U.S. and Canada.
How do rigid lifelines relate to the Z359 Fall Protection Code’s requirements? Do national voluntary consensus standards cover rigid lifelines? How do OSHA and state-plan-states view rigid lifelines?
As far as I know, rigid horizontal lifelines are not currently covered under any current state, national or international standards. Hopefully, this will change very soon since the Z359.17 subcommittee plans to develop a dedicated standard to specifically promote the safety of rigid horizontal lifelines. I hope to be an integral part of this process, and I look forward to working with Thomas Kramer, Z359.17 subcommittee chair, and with the entire ANSI committee to develop the rigid lifeline standard.
This new standard would address the unique requirements of rigid horizontal lifeline systems, such as preventing lateral torsional buckling, accommodating dynamic lateral loading, structural analysis, specifying component compatibility, proper labeling, etc. It would also assist SH&E professionals by removing some of the mystery and confusion involved when comparing or installing a rigid system compared to a flexible system, thereby increasing safety for the average fall arrest user.
What are your thoughts on the U.S. Mine Safety and Health Administration’s guidance on rigid lifelines (http://www.msha.gov/techsupp/acc/application/asap5013.pdf)?
If I understand correctly, MSHA rigid lifelines used in mine safety are different from rigid horizontal lifelines used for fall arrest. MSHA refers to lifelines as directional indicators used to provide pathway and directional guidance to miners on exit paths in the event of an emergency or no visibility conditions.
In the past, you have taken the position that traditional wire rope systems (hemp or wire) can:
From an engineering/physics perspective, how can rigid lifeline systems address these concerns?
The industry seems to be evolving from the first attempts with hemp rope to the current attempts with wire rope and now to rigid lifelines. The differences between a horizontal rope and a horizontal rigid lifeline track are significant. Let’s take a look at some simple physics.
First, the difference in anchorage forces is an eye opener. Remember that all rigid horizontal lifeline systems have absolutely zero lateral pull forces due to sag. No sag means there is no shortening of the distance between the anchorages. This lack of “pull” equates to zero lateral forces. However, compared to flexible rope systems, the current federal law (OSHA 1910.66 App C) correctly quotes the proper physics, i.e., “When the angle of horizontal lifeline sag is less than 30°, the impact force imparted to the lifeline by an attached lanyard is greatly amplified.
For example, with a sag angle of 15°, the force amplification is about 2:1, and at 5° sag, it is about 6:1.” When you do the proper OSHA math, if your maximum arresting force (MAF) is 900 lbs, and your rope sag is 5° or less, your actual anchorage forces will be 6 x 900 = 5,400 lbs. This value exceeds the current OSHA anchorage limit of 5,000 lbs.
OSHA correctly indicates that the anchorage force value limit (currently 5,000 lbs) can easily and readily be exceeded when the rope sag is about 5° or less (which most wire rope systems are) and with potentially catastrophic results for the person falling. This is why both OSHA and ANSI clearly state that you must be a “Qualified Person” to design and install a rope system. The complicated iterations, assumptions, estimates, engineering and math involved to size and install a rope system are absolutely critical to ensure safe operation and user safety. (Note that in the above example, the actual 5,400-lb force would need to be multiplied by two (OSHA factor of safety). Therefore, the correct anchorage for this application would be designed to resist a minimum of 10,800 lbs of force.)
Compare this to the actual anchorage forces on a rigid horizontal lifeline system. Since the newly engineered lightweight rigid lifelines do not sag or deflect during a fall, the resultant lateral pull forces are zero (in the horizontal direction). And as the lightweight rigid lifelines can be as little as 3.9 lbs per foot, the maximum vertical up-and-down forces are the lifeline weight plus the 900-lb MAF. The math is simple and easy with no force amplification factors and no guessing required.
Now let’s take a look at the total fall distance. A rigid lifeline will not deflect vertically and will not add any sag or deflection distance to final fall distance. (This lack of deflection removes a significant amount of potential energy from the fall arrest energy balance equation. This means extra travel clearance and extra energy absorbers are not required to absorb the additional potential energy that develops from wire rope deflection.) Therefore, the total fall distance is easy to calculate. It is harness stretch plus self-retracting lifeline (SRL) engagement distance. What we have seen in testing is only a few inches of drop when using an SRL and a very tight harness that limits D-ring stretch. (Note that a loose harness can contribute to fall distance as the harness D-ring stretches away from the body. This is why a proper fitting harness is so important. Also, some SRLs may pay out as much as 18” before engaging.)
Compare this to a rope system where the actual fall distances tend to be larger than the layman could imagine due to rope sag, rope deflection, rope elongation, elongation of horizontal energy absorbers, elongation of energy-absorbing lanyards, deflection of anchorages, etc. We have seen rope systems where the total fall distance is well over 8 ft. This is why both OSHA and ANSI clearly state that you must be a “Qualified Person” to design and install a rope system. The complicated engineering and math involved to account for all deflections and elongations in the total fall distance on a rope system is absolutely critical to ensure that the worker will be safe from catastrophic failure of anchorages and will not impact a lower level. However, the hazards of impact injuries will still exist due to the much larger fall distances and increased swing hazards.
In summary, SH&E professionals can benefit by taking advantage of the dramatically reduced anchorage forces, reduced fall distances, reduced swing hazards and simple selection of the rigid lifeline systems.
Rigid lifeline systems have portable applications that work well in facilities that with little space. What are the requirements for installing a rigid lifeline system? Can a competent person or qualified person perform the installation? Do you recommend that an engineering assessment be conducted first?
Yes. A competent person could easily select a rigid lifeline system from a rigid lifeline catalogue. If the attachment points are obviously oversized for the given design forces, then the competent person could make that determination. However, if any doubt exists, it is always best to have an engineer or qualified person review the support structure to verify that it can take the vertical design load during a fall.
Systems are normally installed by our network of distributors and their installation crews, but they can also be installed by competent and qualified persons.
What best practices do you recommend for maintaining rigid lifeline equipment? Is additional testing of the equipment required over time and with repeated use?
Equipment maintenance is almost nonexistent since no retensioning, oiling or lubrication is required. Users visually inspect before each use and thoroughly inspect once a year. After a fall event, the system requires only an inspection for defective parts by a competent person, and then the rigid lifeline can be placed back in service immediately. It is not necessary to red-tag the system, shut down the operation, order new rope components or rigging equipment, replace rope components, retension and then recertify. On a rigid lifeline system, you inspect and go back to work. Also, rigid lifeline systems do not “expire” after a few years like some rope systems.
Can rigid lifeline systems be used on construction and demolition sites? If so, how are they installed and tested? How do rigid lifeline systems work at sites that span long distances?
Rigid lifelines are used in construction but seldom in demolition. Systems normally supplied are permanently installed in roofing structures for either overhead fall protection and also for lateral fall restraint. Long spans can either be erected onsite, similar to scaffolding, or on permanent installations and can be easily handled in the design phase of a project. Rigid lifeline systems along beams, walkways and roof edges can also double as handrails for extra safety and stability.
Many different rigid lifeline products are available as portable systems. These generally involve a gantry-style support structure or a counterweighted jib arrangement for stability.
Testing of systems before placing into service is always recommended but not required by OSHA law. The recommended method of testing is to perform the standard ANSI dynamic performance test. This test consists of dropping an ANSI 220-lb test weight through a 6-ft freefall distance before engaging an energy-absorbing lanyard. The orientation of the lanyard should be the worst possible for the given application. In other words, if the worker could fall off the edge of a platform or workspace where the lanyard would generate an angle up to 30° off plumb, then drop the weight off the edge of the platform or workspace. This tests both the unfavorable off-plumb angle and the lanyard strength on the actual edge of the platform or workspace. Note that you cannot test wire rope systems before placing them into service because the drop test will require a complete removal and replacement of the “used” wire rope and the “used” horizontal energy absorber.
We are an ISO 9001-certified company, and we thoroughly test all systems and components to failure during product development to ensure that our products significantly exceed ANSI’s and OSHA’s minimum performance requirements. This validates safety and performance, which we take very seriously.
How are anchorages addressed in rigid lifeline systems? Must a professional engineer review the location of a rigid lifeline system and then approve its use?
A rigid system’s anchorage forces are much smaller than the anchorage forces of a horizontal rope system. These forces are only in the vertical direction and are also easier to calculate. If the attachment points are several times stronger than the design forces we provide, and the strength of the support structure is not in doubt, then a competent person could make a proper determination. In this case, we recommend simple dynamic testing before being placed into use. However, if any doubt exists, it is always best to have an engineer or qualified person review the support structure to verify that it can take the vertical design load during a fall. If the attachment points are approved by a qualified individual, then testing is not required.
What should SH&E professionals look for when using rigid lifeline systems in environments with large overhead cranes where swing hazards are more prevalent?
Swing hazard injuries are the result of the lanyard attachment point not being directly over the worker’s head. If a worker falls, and the attachment point is not directly overhead, they will swing like a pendulum, potentially into an injury hazard. Rigid lifeline systems can dramatically reduce swing-related injuries in three ways:
1. The connector that attaches the lanyard to the horizontal lifeline will not slide downhill like on a rope system or drag behind the worker due to rubbing friction on a rope system. This trailing trolley can create a swing distance and increase the chance of a swing-related injury.
2. If a rigid lifeline is used with an SRL, the slight lanyard tension coupled with the easy rolling, almost nonexistent ball bearing friction of the rigid lifeline trolley wheels will allow the trolley to stay as close as possible to the worker and in the closest overhead position relative to the worker. This closeness of the trolley to the worker potentially eliminates swing-related injuries.
3. After a fall, there is no zip-line effect on rigid lifelines. On a rope, there is a chance for a slide-related injury due to the fallen worker sliding on the sagging rope to the center of the support span. The sliding zip-line effect is more prevalent on rope trolleys with wheels.
The rigid lifeline is a perfect solution to limit swing injuries due to the absence of frictional drag, sag and lifeline vertical deflection.
Miscalculation of fall distances is a serious problem. How are fall distances calculated when working with a rigid lifeline system?
Total fall distance is very simple to calculate and easier to visualize on a rigid lifeline system. Total fall distance is simply the sum of the D-ring stretch in the harness and the engagement distance/payout of the SRL. SRL manufacturers can provide engagement distances and energy-absorbing payout distances (if any) for such a short fall.
During our tests of a rigid lifeline with a full 310-lb fully articulating dummy, we have seen approximately 16-19” in of fall distance when using an SRL with 4-6” engagement and a very tight harness that limits D-ring stretch. With an average 180-lb worker, the results are even better. In our testing with 180-lb volunteers, there was no payout on SRLs, and the drop for an average 180-lb worker was only 12-14”. A few inches of fall are dramatically different from the many feet of fall you would generally see with a horizontal rope system.
How do rigid lifeline systems address assisted- and self-rescue scenarios? Does their installation present any unique challenges not encountered in more traditional systems?
Increasing awareness of rescue planning is of great personal interest to me. Unfortunately, it is a topic that few give much thought to when initially specifying a system. Per ANSI, a competent person as a supervisor should always be present while fall protection equipment is in use. However, in the real world, this may not be the case 100% of the time.
I am sure many SH&E professionals are concerned and anxious about the worst-case scenario in which a worker falls, and no people or equipment are available to help the fallen worker back up onto the walkway or work area. If the fallen worker receives no help, s/he can become injured due to the stretched harness blocking blood circulation in the legs. If the hanging worker is not rescued, s/he can eventually become unconscious and possibly die while hanging in the harness due to this prolonged exposure to suspension trauma. This danger is greatly magnified for heavier workers. Harnesses should always be properly adjusted and rescue provided promptly. Suspension trauma is a huge concern for all workers at height and a true wildcard of vulnerability in fall arrest/protection planning.
From a manufacturer’s perspective, the holy grail of product design is to design a product that would never place users in a position in which they would need an assisted rescue. How do you design and then use such a product? We think we have the solution.
Rigid lifeline systems offer enormous benefits and have tremendous flexibility when it comes to rescue plans. First, when used properly, the chance of being knocked unconscious during a fall, in my opinion, is infinitely small due to the tiny distances fallen compared to flexible rope.
Second, an average-weight worker (about 180 lbs) who loses balance near the edge of a walkway or work area and stumbles over the edge will not activate an SRL’s payout mechanism. We have proven this repeatedly in live testing. In this case, the average-size worker steps back up onto the walkway or work platform. The perfect self-rescue! In the rare occurrence of a worker falling farther than a few inches but less than a few feet, the fallen worker may still be able to climb up or be able to slide laterally to a more favorable place where s/he can climb up.
Third, if a fallen worker is fully hanging in space with no immovable object to grab, the rigid rail allows the hanging worker to swing back and forth in a manner that may allow the worker to propel to a grab point then slide to a self-rescue point.
Finally, if the worker is suspended conscious or unconscious and requires help, another worker can effortlessly slide the fallen worker to a more convenient rescue point.
Furthermore, if it is designed into the system, a rescue hoist can be mounted or hung directly from our rigid lifeline system. You cannot do that with a wire rope system. Also note that I-beams do not lend themselves well to self-rescue because of larger frictional losses, especially when pulling trolleys at an angle perpendicular to the beam. All of the above benefits of a rigid lifeline offer peace of mind for SH&E professionals when it comes to rescue planning.
Rigid lifelines completely eliminate or dramatically reduce these potentials for injury and death due to the dramatically shorter fall distances, which allow quick and easy self-rescue. If used properly, rigid lifelines make self-rescue possible without the need for additional equipment.
If rigid lifeline systems span multiple work areas, the attachment of jib supports to existing columns may be required. What must be done during installation to maintain the structural integrity of the initial supporting columns and materials?
Jib arms are commonly used to support rigid lifelines, such as our standard “foldaway” monorails that fold out of the way when not in use to allow free access to overhead cranes. If the support structure is over-sized and strong enough to resist push and pull forces, no further analysis is required.
For example, if the building columns are large enough to resist many times our published design forces, the choice is obvious. However, if any doubt exists, then a qualified person or engineer would need to verify that the existing columns can handle the resultant forces.
How do rigid lifeline systems address the needs of heavier workers?
Heavier workers present a unique challenge in fall protection, especially where energy-absorbing devices are concerned. In the case of a heavier worker on a rigid lifeline, as long as the energy-absorbing SRL employed by the worker is rated at a 900-lb MAF, then standard rigid lifeline systems can be used “right out of the catalogue.” All of our rigid lifelines are clearly labeled with signs that read “900 MAF capacity” for easy reference.
Heavier workers also have the most to gain from rigid lifeline systems. Since the fall distance is so small, they can use their own legs to step up or climb up for a self-rescue.
If the worker is heavier than 400 lbs and is using an energy-absorbing device rated for the larger (but still OSHA-approved) 1,800-lb MAF, then we can easily choose a more robust multi-person system, de-rate it for one person and then change the labels from our standard 900-lb MAF to the larger 1,800-lb MAF capacity.
When installing a rigid lifeline system, must testing be performed prior to each physical use? If so, how is the testing process conducted?
Testing need not be conducted if a competent person installed the system according to the provided installation instructions and if an engineer or qualified individual reviewed the support structure.
However, if the user prefers to test, the recommended testing method is to perform a dynamic performance test of dropping an ANSI 220-lb test weight through a 6-ft freefall distance before engaging an energy-absorbing lanyard. This is the same test I had described earlier. Again, you cannot test wire rope systems before placing them into service because the drop test will require a complete removal and replacement of the “used” wire rope and the “used” horizontal energy absorber.
From a quality perspective, we thoroughly test all of our systems and components to failure to be absolutely sure of their safety and performance.
How do rigid lifelines and rope access compare/contrast?
Rigid horizontal lifelines can be integrated easily into all rope access systems. The effortless sliding of the connector trolley horizontally offers the rope access worker much flexibility, especially when it comes to supplying rope access to a very large or very wide facade. Curving facades can be accommodated with our standard curved track rigid lifelines. The rigid nature of the horizontal lifeline can allow rope access workers to move laterally across the workface area totally unencumbered with no need to periodically reposition anchorages. The rigid lifeline can also double as a handrail and safety rail at the edge of a roof.
Compatibility is generally not a concern with our systems because:
1. Our systems are clearly labeled for use with 900-lb MAF ratings, and our instructions are very detailed in terms of usage and capacities.
2. We supply easy-to-use and generously sized connector points on our trolleys. These swiveling connector points virtually eliminate the potential for connector roll-out.
3. We sell through a distribution network, and we have local distributor support to assist in user training.
Based on your experience, are fall arrest/protection systems often used in truck terminals and train yards?
Yes. This is a huge market that grows larger every year. For railroad use, we offer a large variety of free-standing, column-mounted monorails. These systems outperform horizontal wire rope and the heavy horizontal structural I-beam tracks because the rigid lifelines trolleys are completely protected by the enclosed track. Therefore, they are not exposed to the elements and cannot be rendered useless by ice and snow (when you need fall protection the most). Also, if an end user wants to replace a wire rope system due to the large fall distance hazards, the rigid lifeline is an easy swap onto existing columns or supports due to the reduced anchorage forces. We have seen entire wire rope systems replaced with rigid lifeline to eliminate the nagging and potentially fall-inducing snagging of the wire rope trolleys on intermediate hangers.
Trucking is unique because truck tarping and trailer snow/ice removal laws are pushing growth and will continue to do so for some time. For trucks, free-standing, column-mounted monorails are popular. Foldaway monorails are useful for truck bays because when not in use, they can be folded away to provide free access for any overhead equipment and unencumbered travel of overhead cranes.
Are rigid lifeline systems used in other countries? If so, how do they comply with international standards and requirements?
We sell many fall arrest systems in Canada. Even though Canada has its own Z259 fall protection standards, they readily accept ANSI/ASSE Z359 design standards. We receive inquiries and have sold many systems internationally, and we look forward to increasing our international sales in the future.
Can rigid lifeline systems be used for material handling and lifting? If so, how are weight loads calculated?
Yes, but there are some restrictions. For example, we can supply systems that are used for both material handling and fall protection, but they are custom-engineered systems. When we receive these requests, we supply two completely separate systems attached to one common and custom-engineered support structure. Per current OSHA law, we require that the material handling portion of the system be locked out prior to using the system as fall protection. If both systems must be used at the same time, then an action plan must be developed prior to the material handling taking place. A complete dry run must also be performed, per the action plan, before workers can use the system. This is similar to the new OSHA crane laws for man baskets that will take effect very soon.
Any final thoughts you would like to share?
From a fall protection product development perspective, this is a truly exciting time to be a part of this industry. I feel fortunate to be part of a fall protection community that takes fall protection and product development very seriously. SPANCO’s upper management and the Z359 committee and subcommittees are all proactive in product development and innovation, training and component testing.
Fantastic developments are emerging from all areas of the fall protection community. SPANCO’s research and development team are currently developing new products that further protect workers from injury, simplify the task of the competent person supervisor and ease the minds of SH&E professionals. One of these new innovations is a self-rescue device that will enable fallen workers to rescue themselves. Being a part of these life-changing product innovations is what engineers live for. And knowing we are savings lives and preventing injuries—that is a great feeling.
He heads the engineering and research and development department for SPANCO, Inc. in Morgantown, PA, which develops rigid horizontal lifeline fall arrest, fall restraint and fall protection solutions.
Galpin currently serves on four ANSI/ASSE Z359 subcommittees as well as on other standards committees dedicated to increasing safety in the workplace.
He is a graduate of Vanderbilt University.