Free falling arbor

[DeletedUser4176]

Some people at the theatre I work at took a bunch of lights off an electric without weighting it. They decided to unlock it, and the 1500 pound arbor came crashing down to the ground. It put a nice dent in the stop, but do you think any other damage might have been caused? Anything that would make the stage a dangerous place to be?

 

[gafftapegreenia]

That's what we like to call a "runaway". Anything that came down with enough for to put a dent in the lock rail deserves to have at least that lineset given a full inspection. The shock load of a flying arbor suddenly crashing to a halt can put incredible stress on all the components of a counterweight rigging system. Sure, those cables might look fine, but they could now fail at any given time at a load much lower than their rated strength.

Get a certified rigger in there to take a look at everything. Chances are he will see this you've never even thought of.

 

[Grog12]

It put a nice dent in the stop, but do you think any other damage might have been caused?

Yes.

Anything that would make the stage a dangerous place to be?

Yes.

Get a certified rigger in there to take a look at everything. Chances are he will see this you've never even thought of.

This is the best advise you're going to get, apart from do it sooner rather than later. By sooner I mean stop reading this and go call one

 

[metti]

Anytime there is a runaway someone needs to get called in to inspect the system. Definitely don't use that lineset until it has been checked and all damage repaired. I would be EXTREMELY cautious about using nearby linesets as well since the force of a runaway can cause damage to other parts of the system.

 

[MPowers]

Lordy, Lordy!!!! This is the season for run-a-ways. I have investigated two in the last two months, the most recent this last week end. The first was at the Gallager at UNI. Pipe going up hit a sprinkler head, doused all the sound and set gear for Blue Man Group, cancelled the entire booking and ruined roughly $1,000,000 of gear.

As others have already said, get a "qualified Person" in immediately to inspect the system for potential problems in the line set and those near it. There are good and qualified rigging companies on the west coast and any of the rest of us will be glad to come out and inspect, but the further away the more the travel and expenses will be.

Now, in an effort to prevent more of these accidents, Here is a list of the very, all too common points in all three of these incidents:

1. All the battens were lighting battens = heavy.
2. All were being stripped of instruments and cable = lots of weight.
3. All were unloaded before the arbor was un-weighted, at least once by policy and intentionally.
4. None were "properly" snubbed, attached to a block and fall or capstan or over haul winch or otherwise prevented from running free if there was a problem.
5. None were being monitored at the moment the out of balance condition began to make the rope move, or that person could have stopped the unloading, or yelled to put weight back on, noticed that the purchase line was becoming too taut, or several other scenarios.
6. It would appear that in each case, IMHO, that the desire to "get it done" as quickly as possible, led one or more persons to rush themselves or their crew beyond the point of being able to keep tabs on the events going on. Kind of like someone texting while driving, just one too many tasks for the brain at the time.

If you find yourself in a tight change over or strike, especially late at night or third shift, slow down. Tell your crew it is OK to hurry but not OK to RUSH! There's a difference! Often slowing down will speed things up as things are done right the first time and only have to be done once. Keep special vigilance on heavy moving objects, vertical or horizontal. Both can injure or kill. Don't let your crew or yourself start to run on "auto" or to "zone out".

Let's make it point not to let heavy things fall, I'm tired of investigating run-a-ways.