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The Guardian Fall Team Blog

And now time for everybody’s favorite—Guardian Fall Protection’s ongoing analysis of jobsite fall protection scenarios, What’s Wrong with This Picture?

What's Wrong With This Picture?

Our picture this quarter may initially be hard to dissect. No, we’re not trying to get artsy on you and give you a silhouette or an inkblot test to look at (though we could try to force a joke or two about negative space). Sometimes the image isn’t perfect…just like the use of the equipment itself.

So we’ll help you out and identify some key pieces of information. Ask yourself, what’s wrong with this picture?

What's Wrong With This Picture? - With Notes

The configuration of equipment shown is as follows: a Beamer Anchor is installed overhead to an I-beam, and a Vertical Lifeline is attached to the Beamer Anchor. A Rope Grab is positioned well down the Vertical Lifeline, and the worker’s SRL is connected to the Rope Grab. The remainder of the Vertical Lifeline is allowed to hang over the I-beam.

Why is this incorrect?

Before discussing the more immediately practical reasons why this configuration scares us, let’s first go to the standards. ANSI Z359.1-07 (3.3.6) tells us that “The length of that portion of the [fall arrester connecting subsystem] between the fall arrester and fall arrest attachment on the harness shall not exceed 36 inches.” The distance shown clearly exceeds 36”, so right away we find the worker is not in compliance with ANSI.

But ANSI Z359.1-07 isn’t the most current standard on vertical lifelines/fall arresters, you might say. What does the Z359.15-14 standard tell us?

Glad you asked! First, it’s important to note that the ANSI Z359.15-14 standard for single anchor lifelines/fall arresters is very new (released in August 2014), so odds are that the vast majority of equipment does not yet claim compliance with this standard. But for fun, let’s take a look at how Z359.15-14 would address our scenario.

What we find right away is that the 36” connector limitation is removed from this standard, which seems to resolve our compliance issue, but if we dig further we find that ANSI has simply just found a different way to limit connector length.

Z359.15-14 tells us that “The total fall distance shall not be greater than 11 feet” (when the fall arrester is tested in accordance with the dynamic performance manual override test detailed in the standard) (3.2.10). And when we start breaking down our fall clearance calculations, the available length of our connector starts to shrink very quickly. Assuming a maximum potential deceleration distance of 48” (that of a standard shock absorber), as well as a potential lifeline stretch/deflection of 12”, we’re left with only 72” left to play with.

Z359.15-14 also includes the requirement that “…the fall arrester shall travel up and down the lifeline without assistance” (when tested in accordance with the function test detailed in the standard) (3.2.11). This means that we have to assume that, while climbing, the fall arrester is trailing behind the worker to the maximum amount allowed by the connector (because the worker is not allowed to position the fall arrester above them as they climb).

What does all this mean? We have 72” of total fall distance left, which basically translates to the total amount of free fall we can allow. And how long can we make our connector if we want to limit free fall to 72”? That’s right…36”. If working above the fall arrester at the full extent allowed by the connector, the worker will fall back to even with the fall arrester (a distance of 36”), and then down below the fall arrester for the full length of the connector (another 36”). And 36” + 36” = 72”.

So, regardless of the standard, our worker is still out of compliance.

But with all that out of the way, let’s think about some more immediately practical reasons why the equipment use shown in this image is incorrect:

1.) By far the most significant reason this equipment configuration is wrong is the potential swing fall allowed by the system. The Beamer Anchor is our fulcrum point, which means the worker is going to swing all the way back to the Beamer, and almost equally as far back the other way, colliding with any obstacles along the way. Whenever possible, it is important to always work as close to in-line with the anchor as possible.

What's Wrong With This Picture? - Potential Swing Fall

2.) Another potential issue is whether or not the SRL being used is rated for free fall. If it is, great, but even then that might not be enough, as we will soon discover. Free fall for SRLs is easy to calculate: it is the distance the SRL is above the anchor. In our scenario this gets a bit more complicated because the SRL won’t start working against the forces of fall arrest until it is level with the fall arrester (which in turn will in effect be free falling until all slack in the rope above it is depleted). The fall arrester is really functioning as our anchor point in respect to free fall. Our worker is going to be free falling until the rope slack above the fall arrester is gone, and until the SRL is level with the fall arrester (at which point the retraction tension of the SRL will begin to work against the fall, thus transitioning from free fall to deceleration). The most free fall a Guardian SRL is rated for is 6’. Already, the SRL is free falling to level with the work surface, which given a normal height worker should come in at about 5’. But then it’s going to fall until level with the fall arrester, and this distance at least appears to be well in excess of the 1’ of available free fall distance we have remaining.

We’ve now covered in-depth all the reasons why this equipment configuration is wrong, so how can we make it right?

There are many potential options, but one easy fix would be to eliminate the Vertical Lifeline/Fall Arrester entirely and simply connect the SRL directly to the Beamer Anchor. And if an obstruction overhead blocks the Beamer Anchor from traveling where the worker needs it to (as it appears might be the case), simply install another Beamer Anchor on the other side of the obstruction. Use a dual leg lanyard to facilitate 100% tie-off when transitioning to the second anchor, and the problem is solved. Swing fall is greatly reduced, any potential free fall is eliminated, and our worker is significantly safer.

Simplicity reigns! Sometimes the best solution is one where less equipment is used.