Horizontal Lifelines – Mounting Options and Fall Clearance

If you haven’t had a chance to read our introduction to horizontal lifelines, take a moment to go back and review the post before we dive in!  Back already? That was quick. Still, what you now understand is that while horizontal lifelines are certainly a great option for fall protection, especially in some trickier situations where rails, carts or other solutions might not work, a good deal of thought and planning needs to go into them. Beginning with, how am I going to mount this line in a way that both allows for its proper use and doesn’t do irreparable damage to the surface on which I’m working?

Luckily, you’ve got some choices.

First, don’t look at your roof or elevated platform and think, “A horizontal lifeline is impossible.” Odds are, it’s not. In fact, horizontal lifelines have a great deal of flexibility in that their intermediate supports can be configured in such a way that system runs around obstructions. Make sure to have a professional take a look at your situation and evaluate it for you.

Now, depending on your needs and the area in which you will be working, your lifeline can be mounted in a number of different ways. Probably what you’ve seen most often is roof mounted lines. The end and intermediate supports may have plates at the bottom that get fastened, via bolts, to the roof deck. Common? Yes. The ONLY option? No. Which is good, because one of the biggest concerns with installing any rooftop fall protection system is penetration. Nobody wants to make a hole in a roof, knowing the potential for leaks that could come with it down the road. In some situations, the building owner will flat-out prohibit it. Luckily, you’ve got the option of non-penetrating systems. These systems are just as they sound – systems in which the uprights do not penetrate the roof, but instead use counterweighted bases.

Still not comfortable with the idea? If you’ve got a wall available, there are systems designed to be mounted on a vertical surface. While these definitely require surface penetration, they leave the roof itself intact. One added benefit to wall-mounted systems is that the anchor point can much more easily be kept at D-ring height or above, allowing for easier achievement of fall clearance requirements (more on that to follow) and the proper use of your fall protection equipment.

Much like the wall-mounted systems, there are overhead systems available. These systems not only make it easier to ensure you’ve got the proper fall clearance (the higher your anchor point, the less room you need below), but also help to keep your lanyard from getting tangled on things as you move around. Of course, this type of system won’t necessarily help you on the roof, but roofs certainly aren’t the only places horizontal lifeline systems come in handy.

Once you’ve figured out how you’re going to mount your system, there are still important things you need to concern yourself with. One we touched on briefly in the article we linked to above is fall clearance.

Fall clearance is the distance you need between your anchor point and the lower working surface to ensure that you are not going to strike it before your fall protection equipment has the chance to fully deploy. Believe it or not, many people never take this critically important piece of information into consideration. Without thinking about the danger, they throw a harness on with a 6’ lanyard and go to work at 10’…12’…15’.   So what’s the problem with that? The problem is that length of lanyard is only one factor in the distance you need to utilize your fall protection safely. In any of those situations – 10’, 12’, or 15’, your fall protection is doing nothing to protect your life and limbs because you will strike the lower level before it can actually fully engage.

What you need to remember is that in addition to the 6’ of lanyard, your deceleration device – whether it’s a rip-stitch or glue pack – is going to expand another 3.5’. The length of your body below the D-ring is going to add an additional 4-5’. Your harness WILL stretch which will add about another 1’. And, if there is any sag in the horizontal lifeline itself, you need to take that into account. When all is said and done, you need about 18.5’ of clearance before you can even consider using a 6’ lanyard with a deceleration device. Keep in mind, too, that this is the measurement from your anchor point. The anchor point should always be D-ring height or above when using this type of lanyard because your maximum allowable freefall distance is 6’ (in other words, if you tie off below the D-ring with a 6’ lanyard, your freefall distance is actually 6’ PLUS the distance from your D-ring to your anchor point).

The example above is just one configuration. You could have a retractable lanyard that locks in a much shorter distance, for example. Whatever variables you have in place, you need to calculate the fall distance each time to ensure that your workers are actually protected.

In the end, hard work often pays off. Horizontal lifelines are no exception. Though you may need to spend a little more time in the planning stages, what you end up with is an engineered system, professionally installed, and customized to your exact needs. You don’t get much better than that!