Hanging track for side tabs

[JLNorthGA]

I was going to hang my side tab curtain track with 3/16" chain and shackles. I was going to use turnbuckles to level the track.

The weight of the curtain, track and carriers is on the order of 250 lbs max. - probably less.

I was figuring on using Home Depot as my supplier for this. I looked online, the 3/16" chain has a working load limit of 750 lbs and the shackles a working load limit of 616 lbs. The 3/8" eye bolts have a higher load limit. The turnbuckles are the problem. The rating for 3/8" turnbuckles is less (on the order of 215 lbs). I will have four chains per track, so the max capacity is a lot higher than my actual weight. Will this give me enough "cushion" so I don't have to worry? The curtains will not have a pulley, they will just be pulled along the track to open and close.

 

[avkid]

Don't limit yourself to the cheap junk at Home Depot.
303-012652 - RiggingWarehouse.com

 

[Footer]

I have never seen any domestic forged rigging hardware at Home Depot. Most of the rigging stuff there is there to secure a boat or to hang flower pots. Its not rated for overhead lifting.

Buy from here or your local/favorite theatrical supplier. Non-forged turnbuckles should never be brought into a theatre.

 

[JLNorthGA]

I have never seen any domestic forged rigging hardware at Home Depot. Most of the rigging stuff there is there to secure a boat or to hang flower pots. Its not rated for overhead lifting.

Buy from here or your local/favorite theatrical supplier. Non-forged turnbuckles should never be brought into a theatre.

As I have to go to Georgia Stage to pick up the track, I'll pick up 8 turnbuckles. I'll inquire about the chain price there - but I think the proof chain at Home Depot should be fine.

 

[MPowers]

Re the turnbuckles, any forged domestic 3/8" turnbuckle has a WLL of 1200#. My preference is for J&J as they can reduce the # of shackles needed, also makes service and maintenance easier down the road.

3/16" G30 proof Coil chain is fine for your use. Shackles are your problem, you won't find 3/16 forged shackles at HD or Lowes et. al. If you use 3/16" chain, 1/4" shackles won't fit most brands except at the end link, often only the pin will fit, not the bail.

 

[teqniqal]

With any structure the weakest link is the first potential failure point. It doesn't matter if it is bolts, nuts, washers, turnbuckles chain, wire rope, shackles, or whatever. This is the reason that you should have a professional help you with these types of assemblies. If you use chain that is rated for 10,000 pounds and a 1/4" pot-metal bolt to secure it, then the entire assembly is only as strong as the pot-metal bolt.

Rigging Standards like those put together by Plasa/ESTA call for a specific safety factor to be applied to the components (Ref: ANSI E1.4 - 2009, Entertainment Technology - Manual Counterweight Rigging Systems - TSP - Published Documents - About TSP Documents, Published Documents, Public Review Documents, Procedural Documents). Each component in your rigging assembly may be rated by the manufacturer using a different safety factor (design factor), so you have to re-calculated all of the parts' rated working capacity (CAP) for your specific application by adjusting the published CAP to the CAP that is applicable to your use.

Only when you have all of the components meeting the minimum CAP for your application can you be assured that the CAP for the entire assembly will be suitable.

You have made one observation that is very common: Turn-buckles almost always SEEM WAY TOO BIG if you size them properly. This is one of the reasons that wire rope is used to trim batten heights - it is infinitely adjustable and costs nothing extra. Trim-chains and other methods are only good for coarse adjustments.

Another consideration that is frequently missed with drapery track suspension is that when the drape is stacked at the end of the track, the lift line nearest the gathered drape is loaded with almost the entire weight of the drape, while the other parts of the rigging are only supporting the batten and track. The lifting capacity for the end lines must be designed to accommodate this concentrated load. You can't assume that the batten is uniformly loaded like it is when the drape is closed and the weight is spread-out more evenly.

Although this does not apply to your situation, there is also another force sometimes applied at the end of a drapery batten that uses a moving drape on a track - that is the tugging on the operator line. This can be substantial for a large drape with a high friction track & pulley system.

 

[MPowers]

Erich,

You are definitely on line with the comment about Turnbuckles and apparent size.

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

 

[MNicolai]

Another factor worth considering is that if your theatre is sprinklered, it's not unwise to upsize your rigging components such that if your sprinkler system engaged and soaked your curtains, things wouldn't start collapsing from the added weight of water absorbed into the goods.

I know a TD who watched his main drape get destroyed when the curtain got soaked by the sprinkler system -- just about destroyed the whole counterweight set. The fire department had to cut the curtains in half to relieve the stress on the rigging.

 

[JLNorthGA]

Securing turnbuckles and shackles

The lift for putting up the track is scheduled for this Friday.

Couldn't get a scissors lift locally and the out of town places wanted $150 for delivery and $150 for pickup. The local place has a rough terrain scissors lift - but it weighs a LOT - so I declined. They do have a 2 person tow behind bucket lift with outriggers. I decided to get that. The rate is somewhat reasonable - because it is local, I can get them to deliver it on a roll-off truck right onto the loading dock.

Anyway - I was going to wire the shackles and the turnbuckles when I put them up. Any suggestions as to which wire to use? I've got steel tie wire for wiring up rebar and I have copper wire (insulated and non-insulated). I've also got zip ties. I can also purchase wire at the hardware store if necessary.

 

[avkid]

Re: Securing turnbuckles and shackles

Traditionally mousing wire is 20 AWG stainless steel.

I also use black zip ties at times.

 

[gafftapegreenia]

Re: Securing turnbuckles and shackles

Copper is too soft for use as mousing wire.

Zip ties were popular for a while but people found out that they become rather brittle with age (not an issue on short term installs).

 

[MPowers]

Re: Securing turnbuckles and shackles

Lots of different thoughts on this. I know people who swear that stainless wire is too stiff and brittle to take the small bends needed. Zip ties can get brittle, bailing wire is not load rated. gafftapegreenia is totally right, copper wire is far too soft and is unacceptable for mousing.

Over the years I find the single most common mousing product is plain 'ole bailing wire. Soft enough to take small sharp bends needed for mousing, strong enough to keep a 75 pound hay bale together when dropped off a truck or tossed from a loft.

There have been venues that I have done annual inspections for the last ten years that had zip ties from the first and I have seen no evidence of brittleness or failure.

FWIW, zip ties are still very common, to the point of almost overtaking bailing wire. The reasons are easy to figure out. Labor time = $$$$ and zip ties are far quicker, especially on turn buckles. Clean look, zip ties all look very clean and uniform. Time and difficulty of installation make stainless a losing solution in today's world.

The point is that there "should" be very little force trying to un screw a shackle pin or back off a turnbuckle. The point of mousing is to prevent rotation of the pin or the turnbuckle body. The most likely cause of such rotation is uneven loading on the hardware where something is rubbing the part with force at the same time that vibration momentarily takes the load off the rotating part. The point of mousing is simply to resist the rotation during those moments of weight unloading under vibration. Mousing is a back-up keeper, not a load bearing device.

For dead hung rigging, IMHO, zip ties are perfectly acceptable. For moving rigging my preference is to use a bolt type anchor shackle with either a cotter pin keeper or a Nyloc nut, i.e. no mousing needed. For turnbuckles in moving rigging, my personal choice is bailing wire.

 

[gafftapegreenia]

Re: Securing turnbuckles and shackles

Mpowers, while I haven't personally worked with equipment moused with zip ties, I have heard the tale of zip ties going brittle from others. Myself, I have found brittle zip ties in other applications, such as cable looms. Perhaps it is not the age, but the quality of the zip tie used.

 

[avkid]

Re: Securing turnbuckles and shackles

UV light degrades white zip ties, sometimes to the point of failure.
The difference between something from HellermanTyton and generic dollar store ties is definitely more evident with time also.

 

[KenLager]

Re: Securing turnbuckles and shackles

I have used the stainless steel lockwire for mousing turnbuckles and have never had it break during installation nor have I come back years and years later and had it gone, degraded or damaged. It takes some practice, but it goes in pretty fast once you get going. You should be able to get it at an industrial hardware store or warehouse distributor (McMaster or Grainger) The manufacturers web site is Malin | Aerospace Wire/ Safety Wire / Safety Lockwire We used the blue can at .025 diameter.


Hope that helps,

Ken Lager
Motorized Rigging Solutions
New York, NY

 

[JLNorthGA]

Re: Securing turnbuckles and shackles

Bailing wire is readily available in our area - so I'll go with that. How rural is our area? - I was at the hardware store the other day and a guy wanted 2000 lbs of seed potatoes.

 

[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.

 

[teqniqal]

Good point for those "special occasions". A Smoke Vent hatch that pops-open during a severe storm will drown a stage pretty well, too. I wonder how one might calculate the water absorption factor for various drapes? Would it matter if the drapes had been ScotchGuarded to make them water repellant? How does ScotchGuard affect the Fire Retardant properties? Synthetic fabrics tend to absorb water less than cottons, too. This poses an interesting set of questions . . .

 

[MPowers]

Re: Securing turnbuckles and shackles

Just for the record J.R. Clancy recommends bailing wire or wire ties (zip ties). From the Clancy web site under the section on "Chain For Theatrical Use" "....for screw pins the pin must be moused with bailing wire or a wire tie."

On the point of UV and White zip ties. First, I would think that all riggers would use black. Second I'm trying to figure how a zip tie would be exposed to a lot of UV unless a vent hatch is stuck open or there's a lot of black light in use and shining on the shackle. In any case for any outdoor, permanent install we simply use a bolt and nut shackle with a NyLoc nut, i.e. no mousing necessary.

As for stainless. There is absolutely nothing wrong with it. It is about twice the cost, takes a touch longer to install, and in most cases, IMHO, I don't believe there is anything gained. If the installation was located near a large body of salt water, either coast or the gulf, I might feel differently.

 

[spribil]

Re: Securing turnbuckles and shackles

From an install point of view, go with the zip ties. you can go wire but then you get into the "right" way to rap the turnbuckle so that it can not spin....put a zip tie on both jaws and call it good.