Counterbalance For Lights

hira · Mar 21, 2024

During our strike on closing night, I was overseeing the counterbalance as we were taking Source Fours and Auras off of 1st and 2nd Electric. On 2nd electric, as I took lights off, I took weight off. This seemed to work fine and everything ended up being in balance. However, when we went to do the same on 1st, we had a failure and the pipe came crashing down, causing some minor injuries. No one is giving me a straight answer on why this happened. We have a single purchase system for context, and we were putting on 20 pounds, maybe 50 pounds once. I think we just took too much weight off, but it doesn't make sense because I had only taken 1-3 weights off, each around 20 pounds and around 5-6 lights each clocking in at about 15 pounds. People have been telling me that as we take lights off, we take weight off the counterbalance, obviously this failed. I want to avoid this problem again, please advise.

Ben Stiegler · Mar 21, 2024

hira said:
During our strike on closing night, I was overseeing the counterbalance as we were taking Source Fours and Auras off of 1st and 2nd Electric. On 2nd electric, as I took lights off, I took weight off. This seemed to work fine and everything ended up being in balance. However, when we went to do the same on 1st, we had a failure and the pipe came crashing down, causing some minor injuries. No one is giving me a straight answer on why this happened. We have a single purchase system for context, and we were putting on 20 pounds, maybe 50 pounds once. I think we just took too much weight off, but it doesn't make sense because I had only taken 1-3 weights off, each around 20 pounds and around 5-6 lights each clocking in at about 15 pounds. People have been telling me that as we take lights off, we take weight off the counterbalance, obviously this failed. I want to avoid this problem again, please advise.

im going to channel our resident certified riggers and predict they will say "You need someone with credentials and experience to be onsite and do a full inspection; it would be malpractice to diagnose this from a narrative without even pictures, and there is now a proven safety risk in your theater". Perhaps you can post where your theater is located, and someone who is qualified and located near you will reach out. We do a lot to help each other here, but also need to respect when safety demands 1st hand observation.

Crisp image · Mar 21, 2024

Agree with Ben. A full inspection and investigation into why this happened. You were lucky to get away with minor injuries.
Regards
Geoff

TimMc · Mar 21, 2024

I am not certain, from this description, whether the failure is with the mechanical system or the human system. I *do* know that we never remove loads from battens before the counterweights are removed. If the pipe is all the way down, it has nowhere to go. This sounds like the line set was pipe-heavy and the lineset was not stayed off (Uncle Buddy, Prussic knot on the operating line tied off the the rail, etc) no matter the loading/unloading circumstance.

Van · Mar 21, 2024

If it was a full runaway, lock-out that Electric/Batten and have it inspected prior to using it again; the dynamic forces imposed on the structure and materials can be considerably. It may be beneficial to request an estimate for a Counterweight Rigging operation training session from the company providing the inspection. It sounds like perhaps you were lucky with only minor injuries.
Thanks for asking for advice and not just saying, "Oh Well" as often happens.

SteveB · Mar 21, 2024

It sounds like the pipe was not all the way in to deck and just locked off at the rail, with the rope lock holding it. Then as you removed units, with an imbalance occurring having more weight on the pipe then on the arbor, the purchase line slipped in the lock, thus the pipe settled quickly to its travel limit,

Counterbalance For Lights

hira

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Ben Stiegler

Well-Known Member

Crisp image

Well-Known Member

TimMc

Well-Known Member

Van

CBMod

SteveB

Well-Known Member

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