required chain grade for overhead suspension

Re: required chain grade for overhead suspension

Tim McCulloch said:
The point of attachment should be 3/8" wire rope sling for loads up to 2,000#; 1/2" wire rope for 2 ton points, probably a "basket" or "split basket" if the beam is particularly large. You should NEVER use a polyester round sling as the *primary* attachment to the building structure.

Wire rope and slings properly made therefrom are used every day to rig many tons of production equipment from arenas. Your fear is unfounded, and contradicted by "best practices" in rigging. The length of wire rope slings you need for a 'stinger' can be easily calculated if you know the hoist chain length, the height of the structural attachment (beam) and the desired trim height. Simple math.

Also note that Grade 80 chain of a size large enough to use a 5/8" shackle will be VERY expensive and unnecessary. This whole thing is a kludge, and I don't understand why you come here asking for guidance that you then summarily ignore.
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+1 "Don't be a Dino!"

Hammer
 
Re: required chain grade for overhead suspension

This thread has really taken a turn for the scary. As such, I am going to clearly state what others have hinted at because it needs to be said:

Tim, you are not a rigger. You (fortunately) seem to know it and we all know it. Rigger's know that their gut does not count more than industry guidelines and best-practices when it comes to material selection, riggers know that they can't use grade 70 chain to rig a line array, and riggers know how to do the things about which you are inquiring without asking strangers on an internet forum. Someone said that they hope you weren't planning on wrapping the chain around the beam you are rigging off of. I am going to add to that: I hope you weren't planning on doing anything. This is serious rigging and, since you are not a rigger, this is clearly well outside your area of expertise and it would be completely inappropriate for you to do it. Furthermore, whether or not this is a union job is 110% irrelevant and if you know the "head rigger" to be signing off on an unsafe design, you sure-as-shit better put yourself in a place to question him. That said, I am thoroughly comforted by the fact that you "don't anticipate anyone doing anything dangerous" since you are clearly so qualified to make this judgement despite all the contradictory evidence in your own statements.
 
Re: required chain grade for overhead suspension

Tim Duffin said:
BTW, this is not a union job and I am not the A1 at the convention center anymore, I'm not in a position to question the rigger. If he signs off on it, its signed off. I don't anticipate anyone doing anything dangerous.
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Safety is everyone's responsibility. If you see, or hear of someone doing something unsafe it's your duty to the client, the audiences, your crew and your own professional reputation to put a stop to it. Clearly the head rigger for this event is a total fucking moron and doesn't know what he's doing. If you aren't going to take the advice of much more experienced and knowledgeable people on this very forum, where you came here and asked the questions yourself, then why even bother in the first place? Please go away and don't come back until you learn some very hard real life lessons.
 
Re: required chain grade for overhead suspension

Justice C. Bigler said:
Safety is everyone's responsibility. If you see, or hear of someone doing something unsafe it's your duty to the client, the audiences, your crew and your own professional reputation to put a stop to it. Clearly the head rigger for this event is a total fucking moron and doesn't know what he's doing. If you aren't going to take the advice of much more experienced and knowledgeable people on this very forum, where you came here and asked the questions yourself, then why even bother in the first place? Please go away and don't come back until you learn some very hard real life lessons.
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Well put.
 
Re: required chain grade for overhead suspension

Tim McCulloch said:
This whole thing is a kludge, and I don't understand why you come here asking for guidance that you then summarily ignore.
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You should understand by now.
This has been his MO since day one with his first "Crown Macrotechs Suck" thread on the old LAB.

Regards, Jack
 
Re: required chain grade for overhead suspension

Tim Duffin said:
BTW, this is not a union job and I am not the A1 at the convention center anymore, I'm not in a position to question the rigger. If he signs off on it, its signed off. I don't anticipate anyone doing anything dangerous.
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As a production manager pal of mine says...that will just put his name ahead of everyone elses on the lawsuit.
This whole concept is several layers of wrong...starting with the spansets at the beam ( you do know they are flammable right?).
Please rent proper motors for this. The life you save may be your own.
 
Re: required chain grade for overhead suspension

I think its interesting to mention that you should "never" use round sling as the primary attachment point. That is all that is allowed in the sac convention center, unless you are using the rated points in the ceiling. Every AV company I have seen has wrapped spansets around the beams to hold their projectors/speakers/screens/cable etc. I think this is a grey area and not a hard and fast rule. Additionally, the AV companies were instructed to pad the spansets with cardboard so as to avoid knocking off the fireproofing. Cardboard is also flammable, strangely enough.

Thanks everyone for your input. I'm just going to buy some 1t chain motors for future shows.
 
Re: required chain grade for overhead suspension

Tim Duffin said:
I think its interesting to mention that you should "never" use round sling as the primary attachment point. That is all that is allowed in the sac convention center, unless you are using the rated points in the ceiling. Every AV company I have seen has wrapped spansets around the beams to hold their projectors/speakers/screens/cable etc. I think this is a grey area and not a hard and fast rule. Additionally, the AV companies were instructed to pad the spansets with cardboard so as to avoid knocking off the fireproofing. Cardboard is also flammable, strangely enough.

Thanks everyone for your input. I'm just going to buy some 1t chain motors for future shows.
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I specifically said "polyester round sling." Round slings made with metal cores (Steel-Flex) may be an alternative.

If you wish to consult a registered engineer that works primarily in entertainment, I can suggest one by PM.
 
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