Originally from: ASSE Photo Gallery
Whether it’s working from a boom lift, walking steel, standing on an elevated order picker, or any of the myriad other reasons you may be working at heights, “tying off” will do you no good if your personal fall arrest system allows you to strike the lower level before it stops your fall. This may sound like common sense, but if working in this field has taught me anything, it’s that “common” sense isn’t as common as we’d like to believe.
While the problem often boils down to a lack of training or solutions developed without the help of a Competent Person, the end result of a fall event in which there was a failure to calculate proper fall distance is always the same: injury or death. Many workers do not fully understand how a Personal Fall Arrest System (PFAS) works and therefore feel that simply “tying off” is their one-size-fits-all solution to safe, compliant work at heights. Unfortunately, this is not true. In many instances, the length of the harness, lanyard, and anchor point, in addition to the length of the user’s body is enough to strike a lower level. So how do you prevent this? By making sure you understand the factors that go into calculating fall distance and ensuring you allow sufficient room for the fall to occur (clearance).
If this clearance is not available (from anchor point to lower level), then you must come up with an alternate fall protection or fall prevention solution.
To an untrained worker, having a 6’ lanyard may seem sufficient while working at a height of 10’ or 12’, but they often don’t know, or forget, about the deceleration device. When a deceleration device is deployed, it adds an additional 3.5’ to the length of your lanyard. Whether it’s a rip-stitch pack, a glue pack, or the bungee style lanyards, you must add this 3.5 feet to the initial 6’. In addition, a harness could stretch so that the anchor point, while initially positioned properly between the shoulder blades, ends up a foot or more above the worker’s head after a fall.
Total Length to Consider: 10.5’
This one is simple, but perhaps the most often forgotten when calculating fall distance. It is necessary to take into account the length of the user’s body below the D-ring. A PFAS that stops the user at 12’ is of no use when the lower level is 14’ away, unless the user is less than 2’ tall. I’d venture to say that this is an unlikely scenario. On average, it is usually safe to consider approximately 5’ feet for this distance. Remember, however, that people on more extreme sides of the height spectrum could warrant different consideration.
Total Length to Consider: 5’ (on average)
A fixed, solid anchor point is easy to calculate because the only distance to add is the length of your snap hook. However, when dealing with an anchor like a horizontal lifeline, things get more complicated. Horizontal lifelines sag, both as part of initial design and additionally during a fall event. This sag needs to be taken into consideration. Figuring out the sag in design could be as simple as pulling the lifeline tight to see what the distance is, but sag from a fall is not as easy to figure. The forces placed on the lifeline are going to pull the line farther than you can when checking the design sag. Estimates I’ve gathered seem to range from 3% of the total length of a high tension line to 15% of the length of a line which uses shock absorbers. This can be significant, especially for lines that have long, uninterrupted length to allow for continuous fall protection during movement. The longer the span, the more sag you’ll have. Your safest bet is to have an engineer calculate the sag resulting from a fall based on the maximum number of people you intend to have tied-off to the lifeline at any one given time. Short of that, you may want to consider shortening your spans and using double lanyards to achieve 100% fall protection. Either way, your sag needs to be figured in.
Total Length to Consider: 3-15% of the length of line, depending on the system’s design for a horizontal lifeline. Length of the snap hook for a fixed, solid anchor
This is exactly what it states: a safety factor. If the total length of my PFAS, including sag and body length is 16’, I certainly don’t want to use it in a situation where my clearance is 16’. I want to build in a safety factor in case something doesn’t go exactly as calculated. The conventional wisdom on this safety factor is an additional 3’, which brings our total length of PFAS including body length to 18.5’ (without sag).
Now think back to your projects, your facility, or work you’ve observed. How many times did you see a 6’ lanyard with a deceleration device used with a clearance of less than 18.5’? Often? Do you think those workers knew the danger they were in but chose to do it anyway? Perhaps, but more likely than not, they were never trained in calculating fall distance and had no idea what was required. Calculating fall distance is not only a good idea, it is critical. Use PFAS only where you have the necessary clearance and where that clearance is not available, find an alternative. It would be tragic to have a worker suffer an injury when both you and the worker thought you were doing the right thing.
Falls remain the number one killer in Construction. Try as we might, we seem to have difficulty changing that fact. The overwhelming majority of fall fatalities occur because the worker was either not provided with proper fall protection, was not trained in its use, or chose not to use it (as opposed to, say, equipment failure). The problem is: fall protection solutions are not always easy. Finding a harness and lanyard might be simple enough, but where am I tying off? If I’m on a roof, for instance, is there anything to which I can tie-off?
There was a time where, short of a parapet high enough to fulfill OSHA’s requirements, the answer to this question in regards to roof work was almost always “No”. Perhaps the only structures on the roof were PVC pipes or large mechanical units with no piece to which you could secure your harness. That’s if there were any structures at all. The only option often turned out to be a warning line and monitor system, which is not really fall protection at all.
However, as technology improves, the “No” answer becomes less and less frequent. No longer do we need an existing structure. No longer do we need to penetrate the roof. Technology has brought us a wide array of mobile anchor points that can help solve many of your most difficult fall protection situations.
Let’s look back at the situation where we had a piece of equipment on the roof that we were unable to tie off to. Well, this may still remain true, but what if there was some supporting structural steel available or an engineer determined that a piece of the equipment was suitable to be used as an anchor point? You still might not be able to find a place to connect your snap hook, but a simple anchor strap could provide you the connection you need
NOTE: Anchor straps are specifically designed for fall protection use. You may NOT substitute rigging slings of any kind. Also, remember that in this situation, you are using the strap around steel. Make sure to protect the strap from the edges if it is not a strap with built-in abrasion protection.
Be sure to keep in mind the rating of the strap. This form of anchor point, just as any other, must be able to support 5,000 lbs per employee attached if being used as part of a fall arrest system. Connecting more could render this solution ineffective.
Tie-back lanyards are similar in concept except, instead of a separate piece of equipment, these lanyards are designed to wrap around your anchor and tie back to themselves. Since this is a major “no-no” with regular lanyards, it is important your employees are trained how to determine which type of lanyard they have.
Speaking of beams, structural steel is a great option when looking for an anchor point (not decorative steel or roof joists, necessarily, but good, strong, load-bearing steel beams). If your work is fairly static in location, you can get a beam clamp and if you need to travel, you can get a beam trolley. Both work under the same principle in which they tighten around the wider part of the beam, but the trolley has rollers.
A few considerations for beam clamps and trolleys:
Similar in look and design to fall protection stanchions that penetrate the roof membrane to be attached to structural steel below, the mobile weighted anchor performs the same task without roof penetration. The weights are broken down into manageable sizes and are moved around in a cart that often comes with the system. The catch here is making sure your employees are properly trained in assembling the anchor point. While not particularly difficult, assembly is more involved then wrapping a strap around a beam or tightening a clamp.
Some manufacturers now produce a “door bar”. This metal bar is adjustable in size and is wedged into place on the far side of a door or window jamb from where the work will take place. Used properly, the door bar can be a quick, easy, and effective solution.
A separate scenario in which anchor points are difficult to find is vertical entry into something such as a manhole. With the necessary retrieval equipment in place, adding additional lanyards could become cumbersome. Fall protection isn’t always required in these situations, but when it is, the simplest solution is to use your retrieval tripod, IF it is also designed as a fall protection device.
A common mistake is the assumption that all tripods provide fall protection. This is not true. In the event of a fall, a retrieval tripod that was not designed for fall protection would just continue to unravel until the employee struck the lower level. Make sure that if you are depending on your tripod, you check the manufacturer’s information to determine if it is suitable for that use. If it is not and you come across this situation often, it could well be worth your while to invest in a tripod that acts in both capacities.
Roof carts operate under similar principle to the roof stanchions mentioned earlier – weights in the cart help counteract the weight of the personnel attached. However, these carts are also designed with “feet” that will dig into the roof, or lodge in the fluting of the metal deck, in the event of the fall.
These carts appear simple, but have some nuances that are important to understand. For instance, many are designed with anchor points that allow for a certain number of employees using the cart for fall arrest and an additional anchor(s) for at least one employee using it for travel restraint. Understanding the cart’s capacity is of the utmost importance. In addition, it’s important to know which direction the cart should be facing based on the type of surface on which it’s resting. Do not attempt to use these (or any fall protection equipment, really) without reading the manufacturer’s instructions and/or being properly trained.
Sometimes, if not often on commercial structures, there is a parapet, but it’s just not high enough to count as fall protection, according to the OSHA regulations. In this instance, you may opt to use parapet clamp anchors. These are similar to the parapet clamps you may see being used as bases for guardrail, but some are also designed to be anchor points. Again, ensure that you are using one designed for this purpose because a parapet clamp intended to only be used as a rail base will not offer you protection as an anchor.
Some operations are a bit different and require a different approach altogether. For instance, in truck washing situations, unloading operations, or rail yard work (to name a few) it may be just as difficult to locate a suitable anchor as it would be during some types of roofing work. For these applications, you may choose to use a rigid lifeline system. While some of these systems are designed as permanent installations, others are wheel-mounted so they can be moved from one part of the operation to the next.
The fact remains that with each passing day, more and more technological advances occur that make the lack of fall protection indefensible. The ones listed above are only some of the products available for use. Many roofing companies still opt to use the warning line and monitor system even when actual protection is available. Sit down and assess your fall protection needs. Find out what options are available to you. Ensure that your employees’ lives are protected. Perhaps then we can knock “falls” off the top of that fatality list.
If somebody was walking on a construction site and saw a 2’x4’ opening in the deck with no protection around it, they would most likely know immediately that it was unsafe. Whether they did anything to fix it is a different story, but they would know that it was an inherently unsafe condition. At the very least, they would probably avoid the area unless they absolutely needed to do work there.
Not so with skylights. Workers - whether construction workers or maintenance workers - on a building’s roof see the glass or plastic covering and assume they’re safe – even to the point where some will sit directly on a skylight to take their break. This has resulted in debilitating, if not deadly, consequences in the past.
The problem is that skylights are designed to protect from things like birds, weather, and small pieces of debris picked up by the wind or dropped by birds. They are definitely NOT designed – in most cases – to handle the weight of a human being. Sitting on one of these, let alone tripping and falling onto one can, and has, resulted in workers falling through to the level below.
One of the issues with skylights is the interpretation of 29 CFR 1910.23(4) which states that:
“Every skylight opening and hole shall be guarded by a standard skylight screen or a fixed standard railing on all exposed sides.”
Some argue that once the skylight has glass or plastic covering it, it is no longer an ‘opening’ or ‘hole’. This is not the case. As argued in Secretary of Labor v. Phoenix Roofing (1995) [http://www.oshrc.gov/decisions/pdf_1995/90-2148.pdf], whether or not there is a covering is irrelevant. What is relevant is the possibility that somebody could fall through. The above case actually refers to the construction standards at 29 CFR 1926.501(b)(4) where each mention of skylights are in relation to ‘holes’. Somebody could interpret, incorrectly, that once a skylight opening is covered, it ceases to be a hole.
The question then becomes, “What do we do about it?”
There are several solutions, but the requirements between general industry and construction are different, so it is of the utmost importance that you first determine which standard applied to the type of work you are doing.
If you are performing maintenance work on a roof, you fall under the General Industry (29 CFR 1910) regulations. The standard states at 29 CFR 1910(e)(8) that:
“Skylight screens shall be of such construction and mounting that they are capable of withstanding a load of at least 200 pounds applied perpendicularly at any one area on the screen. They shall also be of such construction and mounting that under ordinary loads or impacts, they will not deflect downward sufficiently to break the glass below them. The construction shall be of grillwork with openings not more than 4 inches long or of slatwork with openings not more than 2 inches wide with length unrestricted.”
A screen that supports 200 pounds and, if set upon or impacted, does not deflect so as to break the glass of the skylight. Pretty simple. Alternatively, as mentioned earlier, a ‘fixed, standard railing’ is also allowed. To paraphrase the standards, this means a railing that is also capable of sustaining a force of 200 pounds in a downward and outward direction, has a top rail at 42” and a mid-rail halfway between the surface and top rail [29 CFR 1910.23(e)(1) and (e)(3)].
Sometimes people assume that netting or burglar bars can be considered legitimate fall protection for skylights. This is not the case! The problem with these illegitimate methods is that they do not protect the people who may be working underneath the skylight. This is a legitimate concern, as skylights are often used to supplement electrical lighting in warehouses and assembly areas. Falling debris could pose a significant hazard to those working below. In general industry skylight fall protection must protect the worker from falling as well as the integrity of the skylight.
Construction, as always, tends to be a little more complicated, however, if you are familiar with standard construction fall protection regulations, then it’s easy to apply those to this situation. The regulations are basically the same, except that in the construction industry the glass breakage rule does not apply. If a fall through the skylight would be to a surface greater than 6’ away, the employee must be protected utilizing either a personal fall arrest system, a cover, or a guardrail system [29 CFR 1926.501(b)(4)(i)]. Keep in mind, however, that you must calculate fall distance to know if a Personal Fall Arrest system is applicable.
Even where the drop is not 6’ or greater, the employee must be protected from tripping or stepping into a skylight by covers being placed on the openings (and remember, this does not necessarily mean there is an empty void, it could mean there is glass or plastic incapable of withstanding the weight of a worker, equipment, material, or any combination thereof) [29 CFR 1926.501(b)(4)(ii)]. Those same covers would also be necessary to protect workers below a skylight from falling objects.
In the end, a skylight is a fall hazard like any other. If a worker could fall through or step through it, it must be protected. Survey your roofs and know where your hazards are. Determine the proper protection and install it before further maintenance work is done up there. As a construction company, plan what you will do when you have to work around skylights just as you would plan your fall protection in any other stage of your project. And remember, skylights could be even more dangerous than other fall hazards because of the false sense of security the glass or plastic provides. Do not take chances with your employees’ lives. Educate them on this hazard and give them the means to protect themselves.
This is the last and final article in a series that covers that basics of personal fall protection. First we took a look at anchor points, secondly we reviewed body harnesses, and now in this last article we look at the devices that connect the anchor and the harness.
Connecting devices come in four main forms: standard lanyards, shock-absorbing lanyards, self-retracting lifelines and rope grabs.
Lanyards come in three main materials
Each type of lanyard has its own advantages and disadvantages. For example, rope is easily cut or abraded. Steel cable lanyards have no stretch and can conduct electricity, while web lanyards have less stretch than rope, but are more durable and easier to inspect. You’ll have to understand each, in order to select the appropriate product.
Double legged lanyards are available for 100% connection. For example, if you have to traverse around a column, keep one leg of the lanyard connected to one anchor and then attach the second leg to an additional anchor located past the column. Once attached to the second anchor, you can disconnect from the original anchor. This allows you to be fully connected at all times.
Always connect the center of the Y to the D Ring between your shoulder blades. When the second leg isn’t connected to an anchor, never connect it to a strap on the harness. Always connect it to the approved attachment point on the harness.
Using a traditional lanyard and connecting the snap hook back onto the lanyard itself is called “choking” the lanyard.
Either the gate on the snap hook can be overloaded, or since the lanyard strength can be reduced greatly when you choke, the lanyard itself can fail.
There are lanyards available that do allow you to choke. The webbing strength has been greatly increased and the snap hook has been re-designed to withstand the forces generated in this type of fall. This type of lanyard now combines two links in our chain model; the A link (the lanyard acts as an anchorage connector) and the C link (the lanyard connects the harness to the anchor point). Make sure you read the product label to ensure that you have selected the appropriate product.
5,000 lb snap hook which allows the lanyard to be choked.
Shock-absorbing lanyards come in two main styles
Pack or Pouch Style
In order to meet the ANSI standards and OSHA requirements, shock absorbers must have a maximum deceleration distance (shock absorber extension) of 3.5 feet.
Most shock absorbers will limit fall forces to 900lbs with a 6 foot free fall.
“Double packed” shock absorbers are available where 6 foot free falls, or the maximum working weight of 310lbs, are exceeded. You must read the label in order to ensure you have selected the proper shock absorber.
“Double packed” shock absorbers are used for either free falls greater than 6 feet, or for working weights greater than 310lbs, BUT NOT BOTH!!
Retractables are also called “fall limiters”. They are designed to be used with over head anchor points. The term “retractable” refers to the ability of the web or cable retracting back into the housing. Retractables activate when the line speed leaving the housing exceeds a pre-determined speed (e.g. 4.5 feet per second). Most units have shock absorbing capability, so fall forces don’t exceed the maximum forces permitted. In order to meet the ANSI requirements, retractables must activate and come to a complete stop within 4.5 feet. Many now accomplish this in a foot or less.
Retractables have two advantages; they provide a shorter fall clearance and maintain fall forces similar to a shock absorbing lanyard.
Retractables come in a variety of lengths ranging from 6 feet to 195 feet.
Never leave the cable or web extended during storage. A tag line should be connected to the snap hook with the line pulled out when the unit is to be used.
Manual grabs can be used on either vertical lines or sloped applications such as roofing. Watch for the “anti panic grab” or “death grip” feature on manual grabs. While moving the grab in its open position, if you were to fall, most people will keep holding the grab open and you would ride the grab down to the ground.
Trailing or automatic grabs are to be used on vertical lines only. Make sure you don’t use a lanyard that will allow you to exceed the maximum free fall allowable.
Grabs can be used on rope or cable (different products).
Remember with any connecting devices we must keep in mind:
Most shock absorbers limit fall forces to 900lbs
If you haven't already, please take the time to review the other two articles in this series. Our hope is that in helping to review this vital safety information, you and the people you work with will go home safely at the end of every work day.