Rigging incident Adele concert

[JohnD]

At Friday nights Adele concert in Glasgow a fan was injured by a falling chain.
http://www.theguardian.com/music/2016/mar/26/adele-fan-injured-falling-chain-glasgow-concert

 

[Amiers]

At first I thought those were some weird speakers but squinting it looks like they flew the roadcases out and that is their storage. As far as the chain, it looks like its attached to what was a third motor, so point failed? Im surprised the chain didn't take the guys head off.

 

[derekleffew]

... but squinting it looks like they flew the roadcases out and that is their storage. ...

No one is stupid enough to store empty boxes in the air. "Roadcases" are confetti blowers. Notice the conical nozzles on the audience side?

... As far as the chain, it looks like its attached to what was a third motor, so point failed? ...

Suspect chain simply ran out of the bag. Seems to happen all too frequently.

 

[Amiers]

No one is stupid enough to store empty boxes in the air. "Roadcases" are confetti blowers. Notice the conical nozzles on the audience side?

That makes more sense. Guess I just haven't seen a confetti blower that big before.

 

[Footer]

Flip those chains.... check those bags. Either ran over over or bag ripped.

 

[DuckJordan]

Seems like a run chain to me.

 

[petercav17]

Flip those chains.... check those bags. Either ran over over or bag ripped.

Can you explain what that means? In regards to flipping chains and running over over.

 

[JohnD]

Another shot of the chain:

 

[Footer]

Better view of the above post...



I was kind of stumped that you couldn't see two chains in the picture. If the chain ran out of the bag you would see two sides... here you clearly see the hook side laying in the seating... So either someone didn't make a shackle all the way or the point didn't get clipped up right or the hook failed. Really surprised this did not kill the fan or anyone around them.

Can you explain what that means? In regards to flipping chains and running over over.

And "flipping" the chain is just ensuring that the chain is "flipped" into the bag as you float the motor out of the case (or deck/side of case/whatever). Without fail the chain will not find the bag as you start to run the motor so you have to manually start it into the bag. @derekleffew and I both thought this incident was due to the chain "running" out of the bag. The dead end of the chain is stored in a bag that hangs off the side of the motor. As the motor runs it fills up this bag. If the chain stacks in the bag wrong it is possible for the chain to find its way out of the bag. When it does this it will "run" out. Usually it will not hit the deck due to being at close to max trim but it will cause a crazy whip action when it finally runs out. One more reason why if you ever hear a chain running... run.

 

[soundman]

I highly doubt the live end of the chain is what hit someone. Looking at the picture of the truss in the air it looks like all three motors still have tension, and looking how the one point is made there is only about 10 or 15 feet of chain between the motor and hook on the point we can see. A good chance the other points would be built in the same way, and that wouldn't be enough chain to hit the floor. In the photo of the chain on the ground it looks more like a dead end stopper to me than a hook. On slow internet but right now so I can't look up the details but I believe one of the standards requires ultimate limits so the motor can not run the chain out of the motor. As for why we only see one strand of chain, I've seen the quick links that some companies use to attach the dead end to the motor fail if the chain run is long enough.

 

[egilson1]

Better view of the above post...



I was kind of stumped that you couldn't see two chains in the picture. If the chain ran out of the bag you would see two sides....

Not always the case. Deading off the free end of the chain is not the end all be all of stoping the chain from completely running to the deck. Most of the split rings used to attach the chain to the hoist will break open if the chain runs with the hoist near the upper hook. A number of large rigging companies no longer attach the end of the chain to the hoist anymore.

But I am sure this is one of those topics that can be hotly debated.

 

[BillConnerFASTC]

So, I don't work with these much at all, but seems the bottom of the chain bag just failed.

 

[Footer]

Didn't consider the non attached dead end. That does make sense for what we are seeing here.

Sent from my XT1585 using Tapatalk

 

[egilson1]

There are a number of reasons for a chain to fall out of the bag. One is obviously bag failure, either by the bag tearing or the hook or hooks breaking.

Another is a dry chain. Dry chain tends to stack on itself in a taller and more ridged stack. If this happens then the chain can overflow over the top of the bag.

Of course there is always the issue of the wrong sized chain bag, eg a 1/2 ton bag made for 65' of chain used on a 1 ton motor with 120' of chain.

 

[BillConnerFASTC]

So educate me - is it do unlikely the bag failed? It would seem if enough overflowed the top for gravity to pull it all out that it would have been noticed before the audience was in the room. Really - a big loop hanging down? Again, all foreign to me - I think chain motors are unsafe for overhead lifting - but I just can't see this other than bag failure. The dead end would not have been under the pile if it was pulled out of the bag last.

 

[Footer]

Can you explain what that means? In regards to flipping chains and running over over.

So educate me - is it do unlikely the bag failed? It would seem if enough overflowed the top for gravity to pull it all out that it would have been noticed before the audience was in the room. Really - a big loop hanging down? Again, all foreign to me - I think chain motors are unsafe for overhead lifting - but I just can't see this other than bag failure. The dead end would not have been under the pile if it was pulled out of the bag last.

If even a few links are over it can start a run. It basically acts like a slinky at that point. Show starts, crowd gets loud, HVAC kicks in, PA gets going.... truss gets swinging due to confetti cannons and such... that can shake loose the few links that are over. After you get a foot or more out its all over. The whole thing will run. It could have been due to a rip bagged as well. When you have 60' or 120' of something that wants to be drawn toward gravity that weighs a few lbs a foot this can happen pretty easily.

 

[BillConnerFASTC]

If even a few links are over it can start a run. It basically acts like a slinky at that point. Show starts, crowd gets loud, HVAC kicks in, PA gets going.... truss gets swinging due to confetti cannons and such... that can shake loose the few links that are over. After you get a foot or more out its all over. The whole thing will run. It could have been due to a rip bagged as well. When you have 60' or 120' of something that wants to be drawn toward gravity that weighs a few lbs a foot this can happen pretty easily.

The weight of a few links can pull out 60' ?

 

[venuetech]

If the bag is full or undersized a few links over only needs to pull off the top of the pile. Once it gets started momentum takes over.

 

[derekleffew]

So, I don't work with these much at all, ...

... Again, all foreign to me - I think chain motors are unsafe for overhead lifting - ...

Overhead lifting* is exactly the purpose for which these devices are intended. What do you feel is unsafe? What would you propose instead?

*Definition, via the wiki:

That process of lifting that would elevate a freely suspended load to such a position that dropping the load would present a possibility of bodily injury or property damage.

 

[petercav17]

What do you feel is unsafe?

I did once witness an old, overloaded chain motor fail and the truss (which was a Foy rig) freefall 15 feet... Although I'm sure this isn't too common, I do wonder what the frequency of such accidents are. Though it was definitely avoidable had the motor been used properly..