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The Guardian Fall Team Blog

In an earlier blog post, we jumped into the difference between a 6’ and 12’ free fall, and how that determines what type lanyard (standard or extended free fall) is most appropriate for a given situation. In that case, it was kind of an apples to apples comparison; the lanyards were a fixed length, and we learned that anchor position was the sole determining factor as to whether or not the free fall was 6’ or 12’. But what happens when we introduce a variable-length SRL into the mix? How is free fall calculated differently between a lanyard and an SRL? And what difference (if any) does anchor position have on SRL free fall?


Before we get into things, it might be a good idea to refresh our memories of the technical definition of free fall: It is the distance a worker falls unimpeded until a force begins to act against the fall. It sounds obvious, but there has been some confusion as to whether the amount of distance a worker travels during deceleration is free fall (since the worker is technically still falling). The answer, is no. Once a force begins to act against the fall, free fall ends and deceleration begins. This is an important factor to remember when thinking about SRLs and free fall.


First, let’s compare free fall when both the lanyard and the SRL are connected to anchors level with the dorsal D-ring of a harness. If the worker connected via a 6’ lanyard fell, they would fall a total of 6’ before the shock absorber began to deploy and free fall turned into deceleration. However, the worker connected via the SRL would experience zero free fall, and only deceleration. How can that be? It is because the moment the worker falls, the SRL is acting against the fall with both its retraction tension and braking system. In other words, in this situation with the SRL, there is no point at which the SRL is not working against a fall.

By The Foot

What about when the lanyard and SRL are anchored at the worker’s feet? For the lanyard-connected worker, the total free fall is 12’ (if you need a refresher on why, re-read our earlier blog post again). For the SRL-connected worker, the free fall will be – wait for it – 6’. Again, how can that be? Unlike a lanyard, whose length is fixed, an SRL is a variable-length connector. As the worker falls, the SRL retracts the extended cable back into the housing, shortening its length. This prevents any excess lifeline from allowing the worker to free fall below the SRL.



To make this as clear as possible, imagine a worker standing on an I-Beam with an SRL mounted on a beam clamp, say a Beamer 2000. The lifeline component connected to their D-ring is always under tension. Remember, it’s a Self-Retracting Lifeline, and there is always at least some (between 1 and 25lbs) tension on the lifeline. If that worker stepped off into space, the lifeline would retract back into the SRL body as the worker fell until the point the worker was even with the SRL. Then, for the briefest of moments, there would be no lifeline movement at all until the worker moved just below the level of the SRL. At that point, and as the lifeline began to pay out again, the SRL would react and begin to stop the fall. With an SRL mounted at foot level, the only free fall is that which exists until the point the worker’s D-ring becomes even with the SRL. Anything after this point is deceleration because the extra cable has retracted back into the SRL, which then goes into “arrest” mode and acts against the fall.



Don't Take It Too Far

Now, don’t let the above example mislead you into believing that free fall greater than 6’ cannot exist with an SRL; it most assuredly can. Remember, free fall with an SRL is measured as the vertical distance between the anchor point and the dorsal D-ring on your harness. If, for some crazy reason, you decide to anchor your SRL at foot level, then proceed to climb up a 10’ ladder, you are increasing your free fall from 6’ to 16.’ If you were to fall from that dizzy height, you will fall 16’ until your D-ring is even with the SRL at which time the SRL would start to arrest the fall. That’s too much! Guardian permits up to 6’ free fall with our SRL-LEs – that’s it; period, fini, finé, fertig. Did you catch that? Read that last sentence again. Note I said that Guardian permits free fall only with SRLs rated for LE use. Free fall is not permitted for non-LE-rated SRLs, meaning that with a non-LE SRL, you must always mount your SRL to an overhead anchor. How do you know whether an SRL is rated for SRL use? By reading the instructions, of course. Also, look for the following graphics on a Guardian SRL, they will tell you whether or not your SRL is rated for LE use.

Knowing the correct way to measure free fall is a main component of determining your fall clearance. As you’ve seen, free fall for SRLs and lanyards is different, and can be a bit tricky –unless of course, you have been paying attention, which I know you have. Until next time, be safe up there, and measure free fall correctly - your life depends on it.