Safety Cables

[ship]

What is wrong with Aluminum Oval Nicopress fittings? Thats all anyone sells around here are the aluminum ones so thats all we have. I do however check each one against the go/no-go guage and I do crimp in the proper pattern.

Thanks

Aluminum oval sleeves are fine for your fence but for rigging puropses they develop micro cracks especially after just one shock you cannot see. Go on line to any number of sources from the local or national rigging place - industrial or theater, to Grainger or McMaster Carr for the proper ones. Easy enough to get and no doubt cheaper or the same price once shipping is added to the price.

Sapsis Rigging website, believe it was an early edition of "Heads" which brought this to my notice - been years since written but trust me you don't use aluminum, much less most normal crimp tools are not set up for crimping aluminum properly - different gap and gauge if memory serves. This means you might have been over-tensioning the aluminum sleeve which isn't good either. Been a while since I studied aluminum sleeves on the other hand so the different crimp tool is a question. McMaster would list the proper crimp tool for aluminum sleeves, if the same in a size as for copper, than I'm wrong but doubt I am. McMaster would also no doubt have a safety warning about aluminum sleeves.

On snap hooks (not key chain caribiners hopefully = not load rated), that's the current standard though I'm not much of a fan of them. I like Euro snap hooks with thimbles on the wire rope and a load rating tag on the safety cable much better & hope the industry goes that way soon. Unfortunately such snap hooks are not domestically available.

 

[tomed101]

I don't know how common this is but I just noticed that that the Selecon Arena fresnels come with permanent safeties attached to them. Good to see some companies moving in this direction.

 

[lazor]

I-cues come with permanent Safety Cables as well. Makes it very convenient to tie them off. Though I do worry when they strike them that one of these days a student won't be paying attention and that safety will swing around and break the mirror.

 

[FatherMurphy]

Aluminum sleeves are supposed to be more prone to corrosion/oxidation issues than copper, and being a softer metal, less able to withstand shock loading. Properly crimped, the sleeve should be capable of roughly the same load as the 1/8" aircraft cable, so at 2,000 lb breaking strength for 7x19 GAC, a 20 lb lighting instrument is safetied off with a 100:1 design factor - at that point, I'd worry more about the rating of the snap hook being used. This assumes use as a safety only - if your cables tend to get used for other purposes, then aluminum sleeves should be avoided.

I've always been a bit lukewarm about safeties, since they really only protect against clamp failure. However, they make a lot of people feel safer, and for the price of a safety cable, that's a good bargain.

I've only been around one incident where a safety would have been effective, and even then it wouldn't have helped. At a community theater, the LD had yoked a fixture straight out horizontal from the electric, and not tagged the rope lock. An adjacent empty pipe was brought in at a rapid pace, and smacked into the yoked out fixture, breaking the yoke (an old diecast Century Leko) and dropping the light to the floor (tearing the main traveller on the way down). The light hadn't had a safety, but even if it had, it would have only been passed through the yoke. All other fixture falls I've been around have been clamp failures as the light was being hung, or passed up a ladder.

A friend at a TV studio pointed out to me once that since the newsroom lights tended to be left in place for years at a time, thermal expansion and vibration tended to conspire to loosen the main clamp bolts, sometimes backing them out far enough to allow them to fall off the pipe.

At the rental house I work in, we've started passing the yoke through the empty loop of the cable, not just clicking them through the yoke. That's cut down a lot on 'borrowing', since you have to do some work to get it loose again. It's also cut down on customers complaining that we 'forgot' to include the safeties, and it's cut down on customers 'forgetting' to return them.

 

[lieperjp]

I've always been a bit lukewarm about safeties, since they really only protect against clamp failure. However, they make a lot of people feel safer, and for the price of a safety cable, that's a good bargain.

It would be a good time to bring up this old poll, since it pertains to this and this thread:

http://www.controlbooth.com/forums/...ixtures-integral-safety-attachment-point.html

 

[genericcomment]

My only reason for answering all instruments not in storage are safety cabled is because we are short safety cables and we keep stored instruments grounded. Anytime we do a hang we go around finding all the instruments without cables and take them of the ones in storage. I mean at one point every instrument had a safety cable; however I'm sure just irresponsibility led to missing cables. I have no doubt if we went on a deep search everywhere in our facility we could recover them all.

 

[mrb]

this is pretty scary seeing the number of cases where there is stuff in the air with no safety, or with a piece of chain and a keychain beaner, because there arent enough safetys. We are talking about stuff that costs what, $5ea? (its been a while since I have bought any).

 

[LitUp]

Every instrument at front of house positions, and all overstage instruments have safety cables. Pipe booms are safetied and tied off to the grid, but box booms are not safetied or tied off for the simple fact that they're only 8 feet tall.

Dead instruments, whether they're stored in the spot tower, or in the upstage storage are not safetied.

I try to make sure this happens at every venue I'm working in, because the last thing anyone needs is to be beaned in the head by a 6x9 that some yokel forgot to torque down... it's bad enough when you're not paying attention and walk into one of them.

 

[BillESC]

this is pretty scary seeing the number of cases where there is stuff in the air with no safety, or with a piece of chain and a keychain beaner, because there arent enough safetys. We are talking about stuff that costs what, $5ea? (its been a while since I have bought any).

Actually $ 2.50 in quantities of ten or more is what you can find them for. There is NO EXCUSE for every fixture to have a safety.

 

[gafftapegreenia]

Best "Safety" I ever saw was in one of the schools other auditoriums - not under the jurisdiction of the theatre department - it was a PAR 64 that had a black bungee cord as its safety.

 

[ship]

Best "Safety" I ever saw was in one of the schools other auditoriums - not under the jurisdiction of the theatre department - it was a PAR 64 that had a black bungee cord as its safety.

How were the ends of the bungee linked together in being curious?

 

[gafftapegreenia]

How were the ends of the bungee linked together in being curious?

Oh, ya know, just lazily hooked together.

 

[Sony]

You know, when you think about it, if you could properly attach a bungee cords two ends together and prevent damage from chafing, it would probably make a good safety cable. I mean, the stretchiness of the cord would absorb the shock load of the falling instrument over a longer period of time which would reduce the impulse force. This is a sound concept and one of the reasons rock climbers use rope for climbing instead of steel cable, (there are other factors too like weight) because when you fall it slows you down gradually by stretching and helps you absorb the force of your fall over a longer period of time instead of all at once , which could cause injury to the climber.

Really this is a moot point though, smaller fixtures like a source 4 don't really gain enough momentum in such a short fall for a steel safety cable to cause any damage to the fixture and rope is not really durable enough to make a safety cable out of...they would wear out fairly quickly.

 

[gafftapegreenia]

The problem is, in a fire, your safety cable disappears.

 

[Sony]

I think...in a fire, everyone should be evacuated before falling instruments become an issue you should be worried about, but I see thats another valid point.

 

[DaveySimps]

You really have the same issue of a fire when the material is so close the the high heat produced by lighting instruments. Even though you have may not have a fire, an instrument that is bumped out of focus and not noticed could easily melt a bungee. The same hazard could potentially loom when the bungee rest against part of a lighting instrument for a long period of time. Bottom line, a bungee is not safe for overhead use (or any rigging use). Plus, the safety of emergency responders (firefighters, EMT's, etc.) should be considered as well, especially since proper safeties are so cheap.

~Dave

 

[pacman]

All fixtures on safeties... even in storage.

 

[chris325]

There would be no way to properly ensure that a bungee cord would not touch the fixture and melt, so it really wouldn't ever be a good idea.

 

[cdub260]

Do I hear an echo?

 

[ship]

Gee, thanks for steeling my idea on that concept of - would the "safety cable" still be there once it touched the fixture or just during the show drop melted plastic on the audience during the show in no longer being there - this beyond any sort of S-Hook attached to them.

None the less, the Euros in many times being crap have the right idea for safety cables. Load rated and stamped for MFR safety cable with screw locks on the snap hook. More and more I'm going towards it in stocking them these days. Just talked with a TMB rep. this week and with luck they will not just stock the safety cable domestically in each of the three grades or sizes, but also stock the snap hook itself otherwise not domsetically available.

I'm working on the day when safety cables become something that's really safety and say even for a Mac 2K that weighs a bit more than a S-4, perhaps it needs a more load rated safety cable. This beyond other heavier fixtures that still get just a simple snap hook safety cable to make it safe. Mostly on the market without special order these days even the 3/16" snap hook, it's the lesser 1/8" one that even less would support a major load on it.

Hang your school's follow spot from the grid.... it's safe - see the safety cable?