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Safety chains/Safety bonds


johnthughes

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A few years ago whilst working in a school theatre I was told safety chains where obsolete and they all needed changing to safety bonds. This was done. I have recently retired and are now a volunteer in a local youth theatre. All their lamps have safety chains. Question is, are these still legal or do they have to be changed to safety bonds?
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There's no legal requirement to have any "safety bond" of any make, model or style.

 

If you've got one then you should make sure it is of suitable make/model/durability to do the job you think it's doing and also ensure it is suitably maintained in that condition - however this is only to cover your own back in the case of a liability action were a "safety" to fail and a light fall to the ground and hurt someone so that you can show you'd taken basic reasonable steps to do your best to minimise the risk,

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It is a good idea to use safety bonds rather than chains, as they can be reliably assumed to conform to extrapolations from destructive testing with regards to breaking strain and safe working loads.

 

As Tom has said, there is no legal requirement to use secondary suspensions for luminaires, it is just ingrained common practice.

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The venue I was in today have no chains or bonds on anything. Heavy loudspeakers on ancient bits of wire rope twisted and knotted into loops, and they gave me an A frame to use - stored outside, covered in green slime, with two of the cross braces hanging off. On the safety front - a fail. They seemed to have no issues standing on the top platform and stretching to reach the sockets fitted to the ceiling.
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I was told at one venue that the safety manager liked chains because he could count them through binoculars from the ground!

 

It's really a risk assessment thing but most places demand safeties though invariable something in the support system obviously can't be safetied as it's a beam or joist.

 

Any safety needs to suit the load at risk.

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It is a good idea to use safety bonds rather than chains, as they can be reliably assumed to conform to extrapolations from destructive testing with regards to breaking strain and safe working loads.

 

Really??

 

Why do you say that? I can't see any reason whatsoever to 'reliably assume' that a piece of steel wire rope is any more likely to conform to any standard, than a piece of steel chain. Why would that be so? I assume you are getting at the idea that a piece of steel wire rope terminated at both ends is bought for purpose and not just any old bit of chain found around the theatre or bought from B&Q designed for the front door... but realistically anyone can make up a little steel wire drift, and you can buy proper rated chain. I bet there are plenty of people on ebay etc selling "Rated Safety Bonds" that they've made up at home off drums of wire rope from flints with no destruction testing...

 

In my head there is no reason to assume steel wire is any more or less safe than steel chain.

 

Although as I've said before, I'm generally of the opinion that if you use a decent primary suspension - like a half coupler or trigger clamp, which actually wraps the bar - there is no need for a safety anyway, and you can include in your risk assessment hat it is not needed. As Jivemaster said, there will come a point in the lifting chain that something can't have a safety on it, unless you fancy putting a thousand miles of steel wire from your venue roof to safety it off to the moon.

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Although as I've said before, I'm generally of the opinion that if you use a decent primary suspension - like a half coupler or trigger clamp, which actually wraps the bar - there is no need for a safety anyway, and you can include in your risk assessment hat it is not needed. As Jivemaster said, there will come a point in the lifting chain that something can't have a safety on it, unless you fancy putting a thousand miles of steel wire from your venue roof to safety it off to the moon.

 

 

I would hope that it's the walls holding up most venue roofs rather than any means of suspension.

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Although as I've said before, I'm generally of the opinion that if you use a decent primary suspension - like a half coupler or trigger clamp, which actually wraps the bar - there is no need for a safety anyway, and you can include in your risk assessment hat it is not needed. As Jivemaster said, there will come a point in the lifting chain that something can't have a safety on it, unless you fancy putting a thousand miles of steel wire from your venue roof to safety it off to the moon.

 

The issue is that in most situations, the primary suspension is the one that is undone and redone multiple times a week, and so more at risk from human error. I don't think safety bonds are there to catch lights that have been sufficiently loaded (by an adjacent flybar, perhaps) that the primary fails. It's more that the primary is at much great risk of being done up incorrectly (or, potentially, not at all!) So, even with the most whizz-bang primary, for most types of use, I'd say a secondary continues to be a good idea.

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It's more that the primary is at much great risk of being done up incorrectly (or, potentially, not at all!) So, even with the most whizz-bang primary, for most types of use, I'd say a secondary continues to be a good idea.

 

Indeed.

 

Also, given how common it is for the nuts & bolts securing hook clamps (half couplers, whatever kind of clamps) to lantern yokes to work loose with repeated focussing, I'd say that also calls for a secondary suspension regardless of replacing a hook clamp with something more fancy. At least as long as the fancy new clamp is also secured with a single screw thread.

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I can't see any reason whatsoever to 'reliably assume' that a piece of steel wire rope is any more likely to conform to any standard, than a piece of steel chain.

 

The reason explained to me was that with a wire rope the entire batch is made uniformly, and is is tested to ensure it is compliant with whatever capability is is supposed to have. Whereas with chain, each link has a weld, and therefore there is no consistency to the strength, and thus there is the real possibility of (as the saying goes) "the weak link".

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That's the explanation I've often heard but it's based on comparing apples with oranges - comparing rated/tested wire rope with un-rated/un-tested chain. On a purely theoretical level chain is stronger and more durable than wire rope; there's a reason why the big hoists used to lift the truss up in to the sky use complicated, bulky, pain-in-the-ass chains and not considerably thinner, easier to work with wire ropes.
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Back in 2009 we had three topics going on this and the dancing padlocks were like measles around the site.

http://Here!

and here

and again here.

 

I disagree Tom but to cut it short, hoist chain is hot-forged and incredibly more reliable than the cold-formed, spot-welded safety crap. Search Fleabay for Safety Chain for Theatre Lighting and no chain comes up. Loads of wire, though. Seems to be a done deal now for new stuff.

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I assume it's because suitably rated SWR is cheaper than similarly rated chain. I was trying to find direct comparisons but it's tricky. Most chain for sale is much, much higher rated (I found some rated at 17 tons!).
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This matter it is not clear enough and is often ignored, (be it chains are condemned or not) Browsing some manuals of industry standard/regular kit can highlight just that.

 

Smaller safety chains often found in schools and older instaltions are generally not rated. Some do not have closed welds. Most have flimsy lanyard pass holder like clips that would likely take less load than the chains.

 

Steel safety bonds are often rated, and come with a good lockable carabineer. When they are rated for safety, they should comply with IEC/EN standards, for example Martin by Harmon specify using TÜV approved devices. TÜV comply with IEC standards, LOLER and PUWER Regulations respectively.

 

Using the Mac III as an example, the Mac III is a heavy fixture weighing 53.5 kg (117.9 lbs.); we should not assume that a secondary unrated chain will keep it secure… should it somehow become detached from the primary.

 

I would argue that it should be mandatory to follow the safety instructions stated by the manufacturer. However, Companies are not always clear in specifying anything. Nor is it consistent throughout the industry, highlighting your question relating to condemned chains.

 

When reading through the CM Loadstar manual, the company highlight that it must have a secondary safety. Quoting the manual:

 

"Tie off the load with auxiliary chains or cables before access to

The area beneath the load is permitted."

 

And again in the SAFE OPERATING INSTRUCTIONS AND PROCEDURES (CM LOADSTAR)

 

"Warn personnel of your intention to lift a load in the area.

Tie off the load with auxiliary chains or cables before

access to the area beneath the load is permitted."

 

There is no clear specification in this manual relating to secondary safeties. Obviously any trained rigger should be aware of their safety equipment's credentials, though not identified in the manual.

 

Moving into another manual (for moving light MAC III Manufactured by Martin, Harmon), Martin has specified exactly the compliance and also specified that it should be a cable. Quoting the Mac III's manual:

 

"Install as described in this manual a secondary attachment such as a safety cable that is approved by an

Official body such as TÜV as a safety attachment for the weight of all the fixtures it secures. The safety

Cable must comply with EN 60598-2-17 Section 17.6.6 and be capable of bearing a static suspended load ten times the weight of the fixture."

 

Martin Also Specify the same, in the manual for the new Martin RUSH LED Parcans – again specifying it should be approved by a body such as TÜV.

 

"If the fixture is installed in a location where it may cause injury or

damage if it falls, install a secondary attachment such as a

safety cable that is approved by an official body such as TÜV as

a safety attachment for the weight that it secures. The safety

cable must comply with EN 60598-2-17 Section 17.6.6 and be

capable of bearing a static suspended load that is ten times the

weight of the fixture and all installed accessories."

 

However, when looking in the ETC S4 Manual (CE) The Company states that you should use either a cable or a chain.

 

"In addition to primary suspension, attach a safety cable (ETC Part #7060A1022) or chain to the secondary suspension point on the Source Four CE"

 

There is no compliance information given, and inexperienced people may be led to use an unsafe chain for heavier fixtures they may have in their rig.

 

Personally, I would always go with an IEC compliant rated bond (I do not see chains used anymore, Most companies supply bonds).

 

It (should) go without saying....We should never fall into the bad practice of assuming we do not need safeties when ample rigging clamps are present. There is always room for error and avoidable accidents do happen. Items that are not rated for such use, should be condemned.

 

Matt W

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.. there's a reason why the big hoists used to lift the truss up in to the sky use complicated, bulky, pain-in-the-ass chains and not considerably thinner, easier to work with wire ropes.

 

With no need to store the slack on a drum, chain hoists are considerably less bulky than wire rope winches of similar capacity and HOL.

Chain is anything but a pain in the ass compared to SWR in that context: when the time comes to derig, you can drop 60' of 1T chain straight into a cubic foot of flightcase with no need to coil it and no danger of kinking it. Far from bulky, and while it may be complicated to manufacture it's anything but complicated to use.

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