# Difference between grades of chain



## mjw56

Feel free to move this question to a more appropriate forum, i just couldn't think of where else to put it as there is no rigging forum.

So im looking at chain to replace the steel cable which currently supports the raceways and battens on our electrics (5 of them). i think im gonna use 3/8 grade 80 chain(7100# WWL) (way stronger than the 1/8 the aircraft cable(1700# break strength) that's up there now and was installed by a local company, without thimbles in the swages mind u). 
But i was wondering, what is the primary reason that only grade 80 and above is rated for overhead lifting and hanging. for the sake of argument why couldn't i use a 1/2" grade 43 (9,200# WWL).

Id also like your opinion on not having thimbles in the steel cables. frankly i don't like it.

Thanks


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## derekleffew

The Facility Forum seems as good a place as any, as we are dealing with the physical plant.

This thread is treading on thin ice, see 

> The users of ControlBooth, in a effort to police themselves, have evolved the following: No discussion of "how-to" of rigging, pyrotechnics, human flight, stunt falls, weapons and electrical will be permitted. Our stock answer to these questions is always "Consult a qualified professional."


but we'll leave it open as long as no one says "Use X for application Y."

mjw56 said:


> ...But i was wondering, what is the primary reason that only grade 80 and above is rated for overhead lifting and hanging. ...


Short answer: because ANSI / ASTM / ASSE says that's what is to be used. The same reason that only Grade 8 and above bolts are used in overhead lifting/suspension.

You are correct in thinking that thimbles should be used in all terminations of wire rope, with very few exceptions.


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## sk8rsdad

The difference between Gr.80 and Gr.43 is documented in the NACM Welded Steel Chain Specification. Grade 80 is designed to resist catastrophic failure better than Gr.43 will, due in large part to it's elongation coefficient which means it will stretch more before it breaks. It requires almost twice as much force to proof test 1/2" Gr.80 (107kN vs 61.3kN).


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## Footer

As Derek said... because it is. If you are going to put something over someones head, might as well be the best possible thing. This is one place you don't want to cut corners. Grade 80 chain is expensive, but it is the only way to go. It also comes in black if your into that sort of thing. 

By not using a thimble on the line your are cutting the working strength of that wire rope by at least half, if not more depending on how tight the bend is. Its a good thing you are looking at changing it out. I don't think it would survive a quake or something along those lines. For my money, if you are going to dead hang anything chain is the way to go. Its makes life easier if you need to raise or lower a pipe and it makes install faster.


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## mjw56

ok to reiterate. I AM TELLING THE SCHOOL TO PURCHASE GRADE 80 CHAIN and i will not install anything less. there was a rant with a bunch of calcs written out but that probably would have looked like "Use X for application Y." so i refrained.

the school was not happy about the price though. i told the music dept. chairperson nothing less is approved for overhead applications. he said he would talk to the principal.

as for the lack of thimbles. that installation was done by a local company that handles everything from rentals to home theater installs and we haven't modified it in any way. so if it falls, that's on them....i think...i hope. the part where the cable should have a thimble is connected to a 3/8 " quick-link so its a pretty tight bend. 

thanks for the straight answer sk8rsdad. telling a bunch of suits/musicians "because ANSI/Astm/ASSE/I said so doesn't usually work

the comment about the bolts is good to know also as there is a lot of old hardware (probably original to the school so almost 50 yrs old) using god knows what and it should be cheap enough to replace

thanks for the info


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## Footer

mjw56 said:


> so if it falls, that's on them....i think...i hope.



Unless it falls on you. Then its on you. 

Because ASSE says so is a completely valid argument. These are the people that are responsible for making sure bridges stay up and buildings don't fall. I don't think your principal or music dept. head has the knowledge to question these groups. 

If you want to have things overhead, its expensive. Rigging is expensive because it had to be done right. Every grade 8 bolt and grade 80 chain is tested and marked. Huge amounts of time and money go into making sure that the load rating printed on the box is true.


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## mjw56

sorry i didn't mean to sound like they have no value. but we all know (i hope) that those institutions do have value and why what they say is doctrine. 99% of the people i deal with just don't have a clue. if u want to know how to play jazz sax, or write a speech though they would be able to help you out


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## cdub260

mjw56 said:


> as for the lack of thimbles. that installation was done by a local company that handles everything from rentals to home theater installs and we haven't modified it in any way. so if it falls, that's on them....i think...i hope. the part where the cable should have a thimble is connected to a 3/8 " quick-link so its a pretty tight bend.



Now I could be a little off base on this, but I believe that once you (the facility) are made aware of a safety issue, if you do not address it and something happens that results in injury or death, the liability falls squarely on your shoulders. The school district should consult their attorneys and insurance company on this subject.

And I don't believe quick links are rated for overhead lifting.


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## Footer

cdub260 said:


> And I don't believe quick links are rated for overhead lifting.



They are not.... they are just not rated... at all. Tie up your dog with a quick link, use a shackle for anything real. 

This is one of the reasons that I feel ANY hardware entering into a theatre should be grade 8 or rated. If it walks through the doors it could be used for overhead lifting at some point. Might not be for this production, but who knows what will be going on in the future after you leave. I have thrown away more hardware then I can count for this exact reason. I knew I know better, but who knows what the next guy will do. Its a bit extreme, but it does keep things a bit safer.


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## mjw56

hhmmmm. quick links aren't rated for overhead?? im never letting the school work with this company again. that's just ridiculous. 

this might be pushing the TOS but how about screw pin shackles, are they rated for overhead? if this is outside the tos just dont answer it.

a better question might be what standard governs whether or not something, like shackles or quick-links, is rated for overhead use? this way ill be able to know if the materials im ordering are up to snuff.


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## icewolf08

You can buy rated shackles, and they should have the working load stamped right on them. Shackles are standard hardware for lifting across many industries. Generally, and I mean no offense by this, I would only buy shackles that are made in the USA. Or at least I won't buy ones that are made in China!


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## derekleffew

mjw56 said:


> hhmmmm. quick links aren't rated for overhead??...


From http://www.jrclancy.com/Downloads/TFWM0708_McCauley.pdf, article written by David McCauley for _Technologies for Worship Magazine_:

> *Using Quick links instead of
> Shackles to hang things from. *
> Quick links are not for overhead
> lifting; most are not pull-tested unless
> you get specially made ones that have
> the WLL printed on them. One of the
> most important reasons quick links
> should not be used for hanging is
> that if improperly installed, vibrations
> from speakers or the up and down
> motion of lifts can open them up.



The next paragraph happens to be about chain,

> *Using the wrong chain.* Most
> of the chain that is sold at hard-
> ware stores is not made for lifting.
> It has not been pull tested, and the
> manufacturers state clearly that it is
> not for lifting. I see the use of bent
> wire chain “swing set chain” and
> sub grade chain used all the time
> in many applications. This should
> never be done- if you decide to do
> this, you will carry total responsibil-
> ity if something bad happens. Even
> worse, most of the time the chain
> is wrapped around sharp edges like
> beams that will cut the WLL at least in
> half on any chain, let alone substan-
> dard chain. Every link in Alloy grade
> 80 or 100 lifting chain is pull tested to
> over the WLL by the factory. I’ve been
> in the factory when chain has failed
> the WLL test. It sounds like a gunshot
> when it breaks. This does not happen
> often, but it drives the point home
> that a chain is only as strong as its
> weakest link.


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## Footer

icewolf08 said:


> You can buy rated shackles, and they should have the working load stamped right on them. Shackles are standard hardware for lifting across many industries. Generally, and I mean no offense by this, I would only buy shackles that are made in the USA. Or at least I won't buy ones that are made in China!



The chinese forged shackles that you get from most theatrical suppliers are not load tested. The CM ones that you can also buy from most theatrical suppliers are load rated. They also cost 4x as much, but you at least know what you are getting.


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## fredthe

Now, the question is, can you get the original installer to pay for the proper materials to re-hang the pipe, since they improperly installed it in the first place?

-Fred


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## photoatdv

Good point... they used hardware that's clearly not safe... so they should have to fix it. n reality though, unlikely it would happen without lawyers.


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## LightStud

mjw56 said:


> Telling a bunch of suits/musicians "because ANSI/Astm/ASSE/I said so" doesn't usually work.


One would think it would be a more valid reason than "a bunch of anonymous posters ranging from high school kids to industry professionals with 30+ years of experience on an Internet message board told me."


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## mjw56

well having the knowledge to say " the grade 80 chain has a higher elongation coefficient and therefore will stretch more before it fails, hopefully continuing to carry the load after a shock until all personnel are safely away and it can be replaced" is a stronger reason than me, them he, she and they said so. 

i have gone to a hardware/equipment rental store (Wharton hardware) around the corner from my house to get the chain shackles. i believe everything is made in USA and at least load rated. but for safety's sake ill stick to shackles only.
More bad news though. i was in the theater today, looked up and noticed the eye bolts in the beamclips are not solid forged rings, there bent..and not even welded shut.
this place just needs so much work.
does anyone have an extra 100,000$ they would like to donate


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## cdub260

mjw56 said:


> does anyone have an extra 100,000$ they would like to donate



Sorry, I must have left it in my other pants.


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## mjw56

So i talked to the principal today and he assured me that all the rigging in that installation was inspected and is o.k.and that maybe the codes or standards have changed since the install was completed.(late 2005 to early 2006)

i told him i was still skeptical and that i would do a little more research and let him know the outcome.

has it ever been code complaint to install bent eye-bolts (meaning not solid forged eyes) or to install wire rope without thimbles in an overhead application?


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## avkid

mjw56 said:


> So i talked to the principal today and he assured me that all the rigging in that installation was inspected and is o.k.and that maybe the codes or standards have changed since the install was completed.(late 2005 to early 2006)


Unless the principal is a rigger or mechanical engineer he's just spitting out whatever the installers told him.


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## mjw56

i know, but its not like i am gonna tell the guy he has no idea what hes talking about.


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## gafftaper

Just a couple of notes:

Maillon Rapide is a French company who makes the world's only legitimate rated quick links. I just noticed that my sand bag rigging system uses Chinese made 500lb "rated" quick links. Have to do something about that soon. (Van they were installed by your old buddies by the way.)

As for your comment about buying good American made shackles at the local hardware store I'm skeptical. There are VERY few corner hardware stores that stock GOOD rigging hardware (Home Depot and Lowes sure don't stock it). You typically need to go through some sort of specialty dealer located in the industrial part of town or find a Grainger (they carry C.M.). Beyond that your best bet is your local theater dealer or purchasing from one of the national theater rigging companies (call and ask for help). There are a few exceptions but generally, if it isn't made by Columbus McKinnon or Crosby don't buy it.

It sounds like you could really use a rigging inspection. It'll cost a chunk of change but if things are as bad as you think it could save a life. Anybody have a suggestion of who to call in NJ?


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## mjw56

Just checked the catalog. Chain is from Advantage Sales and Supply Company, Inc. and most other hardware (thimbles,clips, eyebolts, shackles, etc.) is from Crosby. the hardware store is actually pretty good. but they also make their own lifting assemblies and custom hydraulic hoses on site. they also rent everything from 100' boom reaches to concrete vibrators.


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## derekleffew

gafftaper said:


> ... Anybody have a suggestion of whom to call in NJ?


Is NJ near Philadelphia?


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## mjw56

yeah, 10-20 minutes away


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## gafftaper

derekleffew said:


> Is NJ near Philadelphia?


Sorry I'm a west coast guy. I forget how tightly packed together you guys are. I'm used to biger states and a 3 hour drive between major cities.


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## mjw56

its still a 2 hr drive from Philly to New York but most things seem to be 15 min away from everything else here in south jersey.


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## ruinexplorer

mjw56 said:


> So i talked to the principal today and he assured me that all the rigging in that installation was inspected and is o.k.and that maybe the codes or standards have changed since the install was completed.(late 2005 to early 2006)



I'd be interested in the actual inspection. Who did it? Can they produce a copy of the inspection? If it was inspected by the same company who did the installation, tnen there would be no checks and balances. Based upon what you are telling us, I'm not sure that there was a proper inspection done. 

What is your role in this theater? Employee, student, volunteer?


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## mjw56

well employee(not officially on the payroll)/consultant/alumnus.the title Ive come up with for myself is stage crew moderator. the crew is all students and they cant do anything unattended in the theater so the title puts me along the lines of a coach. what i actually do though is like everything. i help them build flats, hang lights pull wire, check safety stuff, do capital improvements in the theater, blah blah blah. if anyone has a better, more theatrical type title for what i do throw it out there.

As to the inspection, Ive posted everything i know about it. i don't know who did it or when or how well...one more reason im skeptical. fortunately the teachers have been in strike this week so the actors arent having practice. so im not worrying about the stuff hanging over their heads.


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## mstaylor

There are some good rigging companies around Philadelphia, if you can't get anyone there in a timely fashion PM me. I am going to be in Trenton rigging a show and would be glad to stop by and give a free consult. This would be an informal look, something official would cost.


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## gafftaper

Just a note that a formal rigging inspection takes several days as the person inspects EVERY inch of your fly system. When they are done they will give you a big written report giving detailed information on what needs to be fixed immediately, what is showing signs of wear and should be watched, what is dangerous what is not. If you haven't seen one, such a report is fascinating to read. 

Having someone who knows about rigging (like mstaylor) stop in and just give you some initial impressions would be very helpful. No you won't get a full report of what you need to do, but you will get a good sense of how good or bad things generally are. Which should be helpful in pushing your administration to pay for a full inspection and repairs. To others who may be reading this, I am convinced there is a qualified person at just about every university in this country who wouldn't mind stopping by for a few minutes to give your system a quick look. Don't by shy, give them a call.


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## Charc

Looks like I need to explicitly state something that Derek and Gaff have touched upon.

You are a stone's throw from Philly. Uncle Bill's warehouse is in NW Philly (I live there... NW Philly... not the warehouse!).

Sapsis Rigging Inc is the place you want to contact for your inspection, they are the local guys, and they are in the top tier.

A full inspection might not take days... (Gaff, I've seen Sapsis get in and out in under a day, in a venue probably much larger with many more linesets than the OP probably has.)

Sapsis not only specializes in design and installation, but also inspections. You can trust them, 100%.

Out of curiosity, who DID you use? With Sapsis so close, there really isn't a reason to use anyone else.

*mjw56*, you now know who to contact. Given how many things you've already found out to be not safe. You've already found out enough to warrant a full system inspection. Tell the principal that you've found X number of critically dangerous and out-of-code things with your system. Site the eyebolts, quicklinks, and thimble-less aircraft cable. Explain in detail how each _one_ can lead to a catastrophic failure (it's theatre, use some dramatic words! ) and how it is wrong, and explain what is right. Convince him that the system is broken.

I would like to steal Gaff's common idea, and create a piece of theatre. Have your meeting with the principal in the theater. When you walk onstage, put on a hardhat... give one to him too. Fly something. Point out the quicklinks, explaining that they could open, and everything could fall. Point out the thimble-less aircraft cable, explaining that it no longer can carry its rated load. Point to one of the eyebolts, and take a prop out of your pocket (a cheap corner store eyebolt, already bent open). This should go a long way to making your case.


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## mjw56

Hamming it up for safety is a great idea.
i didnt want to name names but the company is called ****. myself and the LD have both agreed that were never letting them in the theater again. but we are still buying lighting fixtures from them (they had a 20% off sale)
ill check out sapsis and talk to mstaylor about coming to visit.

an inspecion should go rather quickly as there are only 2 uncounterweighted linesets and evetything else is only 25' off the ground.

i really want to thank everyone for their help here because there is so much more going on than just what ive mentioed. jack chain, s hooks, i even found zip ties (which i fixed already). 
an inspecion should go rather quickly as there are only 2 uncounterweited linesets and evetything else is only 25' off the ground.
Again Thank you.


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## mstaylor

Bill Sapsis is definitely the go to guy in Philly, it's what he does, I took a rigging class from him, so I wouldn't have a problem recomending him. Remember the offending company's name, they can be excluded from future bids because of shoddy or dangerous workmanship.


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## mjw56

bids....i wish i could bid a project, most things get done on the "hey, i know an alumni..." basis. but i have no control over that


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## mstaylor

I wish I could do that in my home building but it is a county building so we have to take low bid even if it isn't where we want to get it. I have enough resources that I can make a call and order what I want but if it is over a certain dollar amount I have to bid it.


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## mjw56

my lighting install got half a##ed by an alumni electrician. he didn't communicate any more than he had to. didn't do any research into the equipment being connected and therefore the neutral on our 400 amp service is not sized for 150% of the load from the hots as the install manual suggests and states is theoretically possible. i managed to find that bit of data on my own... on 10 min.....as a senior in high school


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## sdmsc

mjw56 said:


> Feel
> But i was wondering, what is the primary reason that only grade 80 and above is rated for overhead lifting and hanging. for the sake of argument why couldn't i use a 1/2" grade 43 (9,200# WWL).
> 
> Thanks


 
You got me wondering, so I looked up the ASTM specs. 
ASTM A973 / A973M - 07 Standard Specification for Grade 100 Alloy Steel Chain
ASTM A413 / A413M - 07 Standard Specification for Carbon Steel Chain

Of course one has to pay for the entire spec, but the abstract gives some clues. Both call for proof testing and batch destructive testing. But the grade 100 spec says "The alloy steel shall be fully killed and have an austenitic grain size of five or finer." This non-performance-based spec is a big clue. Combined with what I read elsewhere (Oh, I run a test lab for fork lift masts - I put 10,000 lb over my head, and wiggle it around, frequently - I have been looking into this chain business a lot lately!), I see that what they're after are two key things. 1) High ductility, so the chain absorbs a lot of energy after it starts to fail, and 2) High surface hardness, to resist wear. [I recently had a grade 43 chain rub itself to nothing on a hard steel corner, fortunately that was just a horizontal chain keeping the load block up on a set of forks, which were only a foot off the ground]

Ductility and hardness in metals are usually not partners. Generally one goes up as the other goes down. Plain carbon steel won't get there, though it could make comparable breaking strength numbers. So in the higher grade specs they spell out composition, microstructure (that grain size thing above), and heat treatment, on top of the measurable performance specs. 

---
Shawn Mahaney
MSME


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## MPowers

Although the original OP was back in 2009, and probably couldn't care less now, there is a point that seems to be missed all along the way. First, over head rigging is NOT limited to G8 hardware, G5 is what is supplied by rigging manufacturers. Second, but the major point, in the use described by the OP, it is not "Overhead Lifting". That designation is for chain that actually reeves over a cog wheel or winch drum. See the white paper from the JR Clancy web site

http://www.jrclancy.com/Downloads/ChainforTheatricalUse1.pdf

As you see, not only is G30 proof coil fine for theatrical rigging, grade 80 is specifically NOT recommended. If for any reason you need (or feel the need for) a stronger chain, both SECOA and JR Clancy offer a grade 63 theatrical chain that is rated, stamped and fits the shackles, Clancy's is called "Alpha" chain.
Theatre & Stage Equipment Products - Rigging Accessories - AlphaChain.
I prefer the Clancy version as it comes in black.

In reality the OP did his theatre an un-knowing disservice by insisting on Grade 80 chain. The cost was too high and the PITA of trying to use shackles turn buckles that don't fit meant non standard hardware and greater labor costs.


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## teqniqal

gafftaper said:


> Maillon Rapide is a French company who makes the world's only legitimate rated quick links.


 
You can tell if you have these by checking the markings:
Péguet - Peguet - Maillon rapide - Quality / Safety


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## MPowers

I do have to respectfully take some slight exception to your Theatre face articles on chain. The blogs are terrific and the information is invaluable, however, there is some disagreement as to appropriate product for trim chains. The biggest issue is the definition of "Overhead Lifting". As stated in the following papers from the JR Clancy web site, overhead lifting as defined by ANSI et. al. refers specifically to a chain that is reeved over a cog wheel or drum.

http://www.jrclancy.com/Downloads/TrimChains-ESG.pdf
Stage Rigging Systems and Equipment for Theater, Arena, School and Concert Hall


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## teqniqal

Although "ANSI, et al" (any chance you could cite a specific standard?) may refer to chain run over a cog wheel (i.e. a chain motor drive) as the only circumstance as being the 'official' definition of 'overhead lifting', there are many other documents that speak differently. Rarely is anything suspended in the entertainment industry without it potentially being 'overhead'. You can call a cow a duck, _but it's still a cow_.

The _2010 NACM Welded Steel Chain Specifications_ specifically state in section 2.1: "Grade 30 Proof Coil Chain - General purpose, carbon steel chain. Used in a wide variety of applications. *Not to be used in overhead lifting*." (Bold emphasis is theirs.) Only Grade 80 and above are permissible for overhead lifting by NACM standards. The standard further defines 'overhead lifting' in section 3.4: "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."

The _Columbus McKinnon (CM)_ "_Lifting, Pulling & Binding Products Manual_" states "Grades 63, 80, and 100 are alloy chains and due to their strength/toughness properties are the only chains recommended for overhead lifting by NACM, OSHA Standard 1910.184, ASTM Standard A391 and ANSI/ASME Standard B30.9." and _Table 1_ in that document only shows "Recommended for overhead lifting by NACM, ASME, and OSHA." for Grade 80 and Grande 100 chains - it only acknowledges that Grade 63 chain "May be used in rigging and lifting applications."

The ESG 'Trim Chains' article cited also has numerous references to standards that say the same thing. 

The German publication "_Berufsgenossenschaftliche_" _Informations Guide_ (_BGI_ or "_Safety for Productions and Events - Loads Suspended above Persons_" 2007-03-13) describes Grade 8 (80) chain as being more suitable for Live Event rigging. In that document it describes the chains being used for 'freely suspended' objects and where the chain is constrained by being bent over an edge _or_ wrapped around an object.

And in a more general case, commercial riggers worldwide consider all lifting to be 'overhead' and make their equipment selections according to internationally recognized standards (DIN, TUV, BS, etc.) for safety.

*Bottom Line:* Don't use under-rated or under qualified equipment for overhead lifting or rigging. It doesn't matter if it is part of a chain-motor hoist, or not - it is still OVERHEAD. If you won't let your children sleep under it, _then don't do it_.


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## MPowers

I cannot find the specific ANSI code # however, from the JR.Clancy Website.
"...define lifting as 'lengthening or shortening the chain itself by mechanical means, i.e. a chain hoist'. Dead hanging includes raising or lowering an object attached to a length of chain, as long as this isn't accomplished "by the mechanical lengthening or shortening of the chain itself". "When used with in the appropriate workload limits, proof coil chain may be used for dead hanging." 

Further from JR Clancy website: 
OSHA May 1983, "proof coil chain may be used in chain slings if used within the manufacturers recommendations."

In addition, Grade 80 chain is unacceptable and unusable as a trim chain in any application. Why? Grade 80 chain links have such a large wire diameter that any appropriate load rated connection, such as Crosby Loc-a-loy links, missing links, or load rated forged shackles, cannot be used in intermediate links, only in the free end. This means grade 80 chain is OK for suspending, but not for adjusting trim height. 

Combine this with the fact that that 1/4" proof coil chain has a higher WLL than 1/4" GAC, 3/16" Proof coil greater than 3/16" GAC, in fact, properly used, more than twice the WLL of the cable. Properly used, the chain is wrapped around the pipe batten and connected to the cable eye. This means that each section of the chain is supporting only 1/2 the load. So, even in the single path, straight link configuration spec'd by many architects for dead hang situations, the chain is still stronger than the cable it connects to. 1/4" Cable is rated at 875# WLL, 3/16" at 575#. The chains are rated at 1250# and 750#, higher than the cable. Destructive testing by D2 Flying Effects, Clancy, ETC et. al. show the wire rope always fails before the chain. 

For what it's worth, the following companies, who employ licensed engineers, all agree that grade 30 proof coil chain is acceptable and suitable for trim chains and other dead hang theatrical rigging conditions.
J.R. Clancy, Sapsis Rigging Inc. (SRI), Texas Scenic Company (TSC), SECOA, H&H Specialties, THERN, Mutual Hardware, Norcostco.......I'm sure there are other companies that also approve of grade 30 proof coil chain as appropriate for trim chain.

While my engineering degree is only a bachelors and I have never become licensed, (not necessary for university faculty in technical theatre, Freelance Design, film FX or LORT TD work) I do have a fairly good background in the mechanics and implementation of rigging and mechanical forces.

If you have questions I strongly urge you to actually read the following link:
http://www.jrclancy.com/Downloads/TrimChains-ESG.pdf


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## MNicolai

MPowers said:


> I cannot find the specific ANSI code # however, from the JR.Clancy Website.
> "...define lifting as 'lengthening or shortening the chain itself by mechanical means, i.e. a chain hoist'. Dead hanging includes raising or lowering an object attached to a length of chain, as long as this isn't accomplished "by the mechanical lengthening or shortening of the chain itself". "When used with in the appropriate workload limits, proof coil chain may be used for dead hanging."
> 
> Further from JR Clancy website:
> OSHA May 1983, "proof coil chain may be used in chain slings if used within the manufacturers recommendations."
> 
> In addition, Grade 80 chain is unacceptable and unusable as a trim chain in any application. Why? Grade 80 chain links have such a large wire diameter that any appropriate load rated connection, such as Crosby Loc-a-loy links, missing links, or load rated forged shackles, cannot be used in intermediate links, only in the free end. This means grade 80 chain is OK for suspending, but not for adjusting trim height.
> 
> Combine this with the fact that that 1/4" proof coil chain has a higher WLL than 1/4" GAC, 3/16" Proof coil greater than 3/16" GAC, in fact, properly used, more than twice the WLL of the cable. Properly used, the chain is wrapped around the pipe batten and connected to the cable eye. This means that each section of the chain is supporting only 1/2 the load. So, even in the single path, straight link configuration spec'd by many architects for dead hang situations, the chain is still stronger than the cable it connects to. !/4" Cable is rated at 875# WLL, 3/16" at 575#. The chains are rated at 1250# and 750#, higher than the cable. Destructive testing by D2 Flying Effects, Clancy, ETC et. al. show the wire rope always fails before the chain.
> 
> For what it's worth, the following companies, who employ licensed engineers, all agree that grade 30 proof coil chain is acceptable and suitable for trim chains and other dead hang theatrical rigging conditions.
> J.R. Clancy, Sapsis Rigging Inc. (SRI), SECOA, H&H Specialties, THERN, Mutual Hardware, Norcostco.......I'm sure there are other companies that also approve of grade 30 proof coil chain as appropriate for trim chain.
> 
> While my engineering degree is only a bachelors and I have never become licensed, (not necessary for university faculty in technical theatre, Freelance Design, film FX or LORT TD work) I do have a fairly good background in the mechanics and implementation of rigging and mechanical forces.
> 
> If you have questions I strongly urge you to actually read the following link:
> http://www.jrclancy.com/Downloads/TrimChains-ESG.pdf


 
Similar argument to the one I made in our Trim Chain thread.

NACM's definition of Overhead Lifting has a large caveat in it, which is in regards to "freely suspended" objects.


> Overhead lifting: 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.



To which trim chains do not fall into the category of Overhead Lifting, because battens are not freely suspended.

JR Clancy's argument is this, as per the document MPowers linked to:


> The wording is clear; by our interpretation it was carefully written to cover very specific applications where the notable wording "freely suspended" must apply. Whether or not something is freely suspended is a critical aspect of determining suitability for a trim chain application, and one that is nearly always overlooked in discussions about trim chains. Understanding the implications of freely suspended is important. By standard definitions, it implies a concept of hanging something in an unrestrained manner or without restriction or limits. We can easily interpret how NACM standards and OSHA regulations are intended to apply to circumstance such as those present on construction sites: a crane lifting a load on a single (freely suspended) cable.


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## BillConnerFASTC

So in researching this topic for SML (dual listers please disregard) I took exception to some of the comments above. Sorry this is repetitious but this thread came up 3 or 4 on google search and I feel it's important to "complete" the record.

In no particular order, both SECOA and Clancy have alloy chain that is designed for theatrical use, so check out those data sheets and the OSHA sections they reference.

Second, the whole discussion over "overhead lifting" and "freely suspended" has been totally twisted. Some years ago, I spoke with every member of the NACM, both the companies and the individuals at the table when the standard was written and all of the overhead lifting and alloy chain language was developed. I have shared with them photos and drawings of trim chains. About half said with certainty that this was an overhead lifting application and half got their lawyers involved and would not answer. I firmly believe that if you want to know what was intended (and there isn't a court tested precedent) that you should seek that interpretation from the writers. In this case, the reason for "freely suspended" is so far from what people in entertainment technology have tried to use, that the NACM director chuckled.

Third, the Clancy reference to the May 1983 OSHA statement is a little misleading. The whole statement in it's entirety from OSHA:

"The use of other than alloy steel chain is not prohibited specifically in 29 CFR 1910.184, but only alloy steel chain is recommended by chain manufacturers for overhead hoisting. Proof coil and high test chain is used for purposes where failure of the chain would not endanger human life or result in serious damage to property or equipment. Proof coil and high test chains should only be used in accordance with the manufacturer's recommendations."

It seems simple to me. OSHA and the chain manufacturers say trim chains are overhead lifting and alloy chain shall be used. The fact that SECOA and Clancy have products for the application that comply with the regulations and add insignificant cost to a basic lineset makes this all a simple discussion. 

Sorry for the rant but I don't want to leave just one side and what I feel is inaccurate information. Also, I want to be clear, that my position is about the regulations and what is required by law, not what makes sense, is sufficient design, or is safe. If you want to argue the engineering issues, don't bother, I've heard them all, and suggested that those that are interested undertake changing the regulations which require alloy chain be used for trim chains.


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## MNicolai

@BillConnerASTC, have you contacted Clancy about their published interpretation of what "freely suspended" means?

From a regulatory perspective, I'd say that the lack of legal precedence in this matter is where "freely suspended" throws a wrench in the works. I'd prefer to not see our industry test the bounds of that though and get that term defined via a legal preceding following an accident. Instead, I'd want to see either/both the OSHA and/or the NACM standards amended to reflect the intentions of the original writers.

I understand the case you're making, but I fear that just because the drafters of the original clauses and definitions intended otherwise, does not mean that Clancy's interpretation is incorrect. Clancy's interpretation of "freely suspended" may still be valid until/unless legal precedence declares otherwise, or until/unless NACM and OSHA amend their standards to more clearly reflect what they consider the terms "overhead lifting" and "freely suspended" to mean.

------

I want to point out for anyone following along or finding this via Google -- whether or not you follow regulations, if you design any form of rigging that gets someone killed, pointing back at the regulations and saying you followed them to the tee won't get you off any hooks, even if you've got an argument you want to make about the legal definitions of "freely suspended" or any other technicalities you want to argue.

Whether or not someone you use overhead-rated hardware, if you rig something that gets someone killed or maimed, you're going to see the inside of a courtroom. Not to mention that you've then got to suffer living with yourself afterward. Whether you're sued until you've no more assets to litigate after, or you go prison for negligence, you're going to get in trouble unless you can prove beyond a shadow of doubt someone else was at fault _and_ if you can prove you were not at fault (you could still get in trouble for contributing to an accident, whether or not someone else was at fault for the immediate cause of that incident). Your argument about a technicality just changes the degree to which you are an easy target (and yes, if you rig something and someone gets hurt using your rigging, you're an easy target no matter the cause and no matter the technicality used in your defense).


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## BillConnerFASTC

I assure you it has been discussed at length with the people at Clancy, SECOA, and many, many others. You are correct that a court decision could change the original intent, but until that time, I feel on more solid ground using the term as the people who coined it say they intended.

It is simpler. Just find a chain manufacturer that will review the application and write a letter saying that their grade 30 or other non-alloy chain is recommended for it. Honestly and openly and with full disclosure. I can't. So much of it from many parties is based on partial or selectively edited statements, like the excerpt above you mention without the full text that contradicts the impression of the excerpt.

I'm not worried about grade 30 trim chains in use for the most part, including on systems I specified before I learned more. On new systems and on renovations when changing the lift lines, there is no reason not to comply. The cost of STC or Alpha is too little more than grade 30 to even consider otherwise.


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## MNicolai

Now's probably not a bad time to bring up PLASA's standards:


> A.3.18.3.3(c) Trim chain assemblies shall be fabricated of chain approved by the manufacturer for the application. The wire rope eye termination shall pass through the end link of the chain. The chain shall be long
> enough to wrap one and one-half times around the batten and return to connect at the eye termination
> using a load-rated connection. The installed trim chain assembly shall have a breaking strength greater
> than the breaking strength of the wire rope.
> 
> A.3.18.3.3(d) Any chain used in a single load path assembly shall be certified in writing by the chain manufacturer as suitable for the intended application.*




> ANNEX A (This annex contains informative notes that are not part of the normative requirements of the standard.)
> A.3.18.3.3 Wire rope terminations, paragraph (d)
> The typical trim chain assembly described provides a multiple load path between the batten attachment
> and the lift line. The intent of the section is to require either a) manufacturer’s certification that the chain is
> rated for overhead lifting, in accordance with NACM definitions, or b) manufacturer’s certification that the
> chain is suitable for the intended application if its material properties and strength characteristics do not
> meet or exceed that of Grade 30 Proof Coil chain. As of the publication date of this standard, only Grade
> 80 or higher alloy chain is acceptable by the NACM for overhead lifting.


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## Footer

Personally I will be happy when my space has its lift lines terminated with something besides a clove hitch and a few cable clips... Grade 30, grade 80, whatever. It really surprises me that we spend this much time talking about and writing standards for this.


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## MNicolai

@BillConnerASTC and I were chatting via PM and he asked me specifically what my interpretation of "freely suspended" meant. I was originally going to PM it to him, but I felt instead I should post it here for the masses.

I believe I derived my interpretation from Clancy's white paper 3 or 4 years ago, but have recently been swayed from it by the information that's been presented. My understanding of the term is to mean that something is suspended in such a way where the sudden release of that lift line would release the load or cause it to destabilize and swing in such a way as to present risk of injury or harm to people below it. Per Clancy's explanation, I considered a batten to not fall into that category, as the entire assembly of the rigging for a given batten is such that if one lift line failed, the others would partially compensate for the failure. I also considered a freely suspended load to be one that was at risk of additional, significant dynamic loads due to an ability to swing around, which a batten is suspended such that it would not swing around wildly.

By that understanding, a speaker cluster suspended on one or two chains would be freely suspended. If one chain, then the failure of that chain drops the load. If two chains, then the failure of one chain likely precipitates a failure of the other, and even if it doesn't, the load center of gravity would suddenly shift in such a way as to turn the 1200lb load into a pendulum of death.

If that cluster is evenly suspended on four lift lines of chain though, each chain with a capacity of 7x that of the full load being lifted, then the failure of one chain, while precarious, does not send the entire load into a tailspin that drops the load or causes a pendulum effect that likely causes the rest of the chains to fail in a catastrophic domino effect.

Potentially the greatest flaw in that interpretation though is that its highly subjective. So much so that the only way to determine if a given design is safe, to more precision than someone's gut would tell them, is to run destructive simulations on potential methods of failure.

What we're talking about here for a facility with 36 linsets, 7 lift lines ea, is $2750 for G63 alloy trim chains, versus $750 for G30 trim chains. Before I got into consulting at my current position, I would've happily been the end user to say I want my $2000*, G30 is just fine. Now though, I'm far more apt to say, the extra $2000, aside from being the right and just thing to do, is a drop in the hat in the construction of a $15M theater. It's a lot different seeing the world from the eyes of a consultant. $2000 out of $15M is perfectly alright for helping me sleep better at night though.

*Those numbers were based off of prices I got from Sapsis' website. I'll bet there's even less of a difference, G30 versus G63 with a volume discount.

Bill's swayed me. The cost difference is negligible. Like him, I'm not compelled to go so far as to say G30 trim chains need be immediately gutted and replaced. I still think the language used by NACM and OSHA needs touching up though. That "freely suspended" phrase can really pivot the entire interpretation of what "overhead lifting" is, thereby undermining _all_ regulations that reference overhead lifting.


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## gafftapegreenia

Footer said:


> Personally I will be happy when my space has its lift lines terminated with something besides a clove hitch and a few cable clips... Grade 30, grade 80, whatever. It really surprises me that we spend this much time talking about and writing standards for this.




And I will be happy when my alma matter finally gets the last dog clips off its trim chairs. The things that were acceptable in 1975. 


Sent from my iPhone using Tapatalk - now Free


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## BillConnerFASTC

NACM who I believe introduced the ter "freely suspended" said it simply meant the load was not restrained, because if it was even alloy chain might not be strong enough. Anchor the load to the floor and the chain might fail. I suggest when reading codes and standards don't try to find deep hidden meanings in the words.


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## MNicolai

Plot thickens on acceptability of G30 chain and if a manufacturer will endorse it for overhead applications. Seems CM shows this in their theatrical products catalog.


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## BillConnerFASTC

Are they the manufacturer of the chain or simply a re-seller? Now, I acknowledge that is not as easy as it sounds, as for instance SECOA's STC is manufactured for them by another company, but for the purposes of recommending it for the overhead lifting application, SECOA is the manufacturer. Similarly Clancy and Alpha Chain. (In the small world category, they are made in the same factory.) So I've seen this add but I also have heard engineers say grade 30 is OK for overhead lifting - but that doesn't change the fact the manufacturers say it isn't, and I don't want to ever have to defend going against a manufacturer.


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