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Rigging, Truss and Pipe
Churches often do their own rigging. Our checklist could help your church avoid a rigging failure.
Look up into the air! Is it a bird? Is it a plane? No it's, it's.... Well it really isn't that interesting. It's not Superman, you know, just a piece of lighting truss. Of course like the mild-mannered Clark Kent, plain and boring on the outside, truss and the accompanying rigging are as strong as steel and do super feats to keep the lighting gear it holds from dropping out of the sky, and that's pretty important if you think about it.
So why is truss, pipe, and rigging equipment important anyway? Well, the lights have to hang off something. Usually that something is a catwalk, a pipe batten, or a truss.
Pipe, truss, and all of the equipment used to hang stuff from the building's structure is collectively called rigging and is one of the unsung heros of the lighting industry. It's part of the primary infrastructure of a lighting system and one of the unseen expenses of the system, as well as one of the most dangerous parts.
Anytime that you hang something above head height there is always a risk of injury or death if the item decides to fall. Incorrect rigging could fail and cause the lights hung with the rigging to fall.
Although the failure was caused by wind, the collapse of the truss roof at the Indiana State Fair earlier this year poignantly demonstrates the amount of destruction that can happen when a truss fails. As such, it has to be said that rigging is not a do-it-yourself kind of job.
Beware of DIY jobs
Most do-it-yourself rigging jobs that I have seen in both theaters and churches tend to be poorly done. Here are just a few of the common issues I have seen. Count how many of the questions you can answer "yes" to about your system-it will help you determine the quality of your rigging.
Does your system use dog chain, S-hooks, or dog clips to rig with? All of these items are made with soft steel or aluminum and tend to bend open or crack and break under weight. Only welded link or forged chain rated for overhead lifting or rated steel air craft cable should be used for rigging purposes.
Are you using quick links or climbing carabiners for rigging purposes? Ideally, shackles should be used in place of quick links and carabiners because a partially open quick link or carabiner can reduce the load rating of the item by more than half, causing it to fail at a much lower weight load than it is rated for. If you have shackles, are they "moused" with wire or zip ties so that the pin of the shackle can't work its way out over time?
Are you using cable or "Crosby" clips on your steel aircraft cable? Were they properly tightened with a torque wrench to the manufacturer's specification? Are they attached the correct way? Do you inspect them every year? Cable clips tend to loosen with time as the cable stretches and settles. It is not uncommon to find cable clips that are not even finger tight or that are installed backwards, both of which greatly increase the odds of failure. Cable clips need to be inspected and retightened with a torque wrench every year. Instead, use cable swages [sleeves] as they don't work loose over time.
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Greg Persinger is the owner of Vivid Illumination. He can be reached at greg@vividillumination.com.
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