The 411 on Compatibility

By Kevin Denis

The sentence …”to any object that is incompatibly shaped or dimensioned…” appears frequently in occupational health and safety regulations and many organizations fall protection policies. It’s very easy to say “all connections must be compatible”, but what does that mean? To put it as simply as possible, compatible means the two pieces being connected together (snap hook to D-ring) are sized and shaped in such a way that the gate of one cannot rest against the edge of the other. Roll-out, fall-out, burst-out, unintentional disengagement, and forced-roll-out are terms used to describe the concern when a connection is incompatible. When the gate of one can rest against the structure of another, there is a chance the connection can fail.

This issue has been present since people started using gated hooks. Ever tied up your dog only to find it roaming the community later on and nothing on the leash is broken? Take a close look at the clip and collar. Chances are they are the wrong size or shape and with a little twist can come apart. The same thing can happen with tow straps, boat hardware, lifting slings, livestock leaders, and unfortunately, fall protection equipment.

Here are some steps you can take to make good connections:

1. Use ANSI (Z359.12 or Z359.1-2007) compliant connectors.
These connectors have gates rated, side and front, to 3600 pounds. These are the strongest connector gates money can buy.

2. Anchor overhead.
Gravity and the weight of the hook will naturally prevent it from twisting over the anchor.

3. Include flexible elements.
Allowing the connection to move is a good thing. Connections that can swivel, flip, roll and flex prevent the hook from getting caught up on the anchor.

One of the greatest misconceptions I hear is “as long as I use all equipment from one manufacturer, all connections are compatible”, and this isn’t true. All manufacturers have larger gated connectors (ladder hooks, rebar hooks, scaffold hooks) that are incompatible with their standard harness and anchor d-rings. These hooks typically go directly into the structure, where determining compatibility is an even a greater challenge. There are thousands, if not tens of thousands, of different connections that can be made but determining if they are compatible does not have to be difficult. It requires all at-height workers to take a moment, look at what they are connecting into and determine if there is a chance the connection comes apart. No connection is guaranteed and there is no magic hook that ensures compatibility for all connections. Take our connector quiz to see various typical connections and ask yourself if the connection is compatible or not!