Is it safe to connect a Karabiner to a Karabiner?

This question is eventually asked by anyone who uses Fall Arrest / Fall Restraint equipment when ‘working at height’ and there are always two answers depending on who you talk to.

“Never connect a Karabiner to a Karabiner…. it’s not safe!”

Or…

“Karabiners are simply load bearing devices and if the rating is good then go for it….”

But which one of these statements is true?

 Coming initially from the Material Handling Industry, and looking at it from this perspective, one would assume that if the Load Capacity / Rating is adequate for the potential loads, then there shouldn’t be a problem. But is it more complex than that?

Looking for a consensus, my research has taken me to a lovely article written in 2014 by a Mr John McKently from the CMC Rescue School in California USA

Mr McKently discusses where discusses where the “Don’t connect a Karabiner to a Karabiner!” statement originally comes from: -

“It’s probably best to look back to where that statement originated—in climbing and caving. Many years ago, the artificial anchors used in those activities were usually bolts or pitons. The concern was that chained Karabiners could possibly compromise the integrity of the anchor by levering it loose when it was loaded.

Additionally, the Karabiners being used at that time were usually non-locking aluminium ovals. There was the possibility of damage to them if they were torqued when loaded because of the fixed attachment at the end of the chain. “

“Those concerns had some validity, but conditions are usually different in our rescue situations.

We don’t see any issue with connecting a Karabiner to a Karabiner as long as two conditions are met.  The Karabiners should be “floating,” meaning they are not able to come into contact with a hard surface and are free to rotate if necessary. That will prevent damage due to torque loading.

The anchor should be constructed of rope or web, which will flex. Even if your anchor was a bolt hanger, adding a “soft link” of webbing between the anchor and Karabiner would allow the Karabiner to flex and rotate when loaded.

Most artificial protection now being used has some sort of cord, web or cable connecting link that may take care of that for you. For rescue applications we’re typically constructing anchors with tied or pre-sewn webbing or rope so this usually isn’t a problem.

There are times when we would like to attach a Karabiner to a Karabiner. It might allow us to change the orientation of a pulley 90 degrees and reduce friction of the rope dragging along a side plate. Or, adding a Karabiner is a quick way to change the orientation of the litter on a guiding line if necessary.

“No metal on metal” was the concept of not attaching a Karabiner to a Karabiner carried to an extreme. We have known of agencies who have made this statement but it’s obviously impossible to implement.

They got rid of their anchor plates but how do you connect a descent device to a harness with a metal “D” ring attachment?

What about the metal “D” rings on the end of an anchor strap, how do you connect a pulley, anchor plate, or MPD to them?

It is impossible not to have metal on metal in rescue rigging; it is a matter of knowing why the rule came about and how to make those connections safely.

John McKently
CMC Rescue School ©

John gives an in depth view of where the considerations for each argument comes from and his thoughts as to the safety of the practice.

If you would like to read Johns Blog please do so here:

https://www.cmcpro.com/linking-a-carabiner-to-another-carabiner-is-it-safe/