James Posted January 27, 2004 Share Posted January 27, 2004 Guys, I'm not a rigger but I'm working on an amateur production at the moment and something has gotten me a bit concerned . The person doing the lighting has flown a bar FOH from three safety chains. This is a 20' long 20-30mm dia bar with 6 500w fresnels and two dimmers hanging on it. This is above the audience. The safety chains are just the standard type. and are attached to the bar via hook clamps. I wasn't worried about it but during act 2 of the dress yesterday the DS roll drop rigged by the same person snapped and came loose, so I have started to worry about what other corners he might have cut.... James Link to comment Share on other sites More sharing options...
gareth Posted January 27, 2004 Share Posted January 27, 2004 This sounds highly dodgy. Safety chains are not intended as a primary means of suspension. Proper rated steel wire ropes and hanging hardware aren't exactly expensive. Perhaps a quiet word with the person in charge of the production might be in order. And what's with hanging dimmers on the bar? Link to comment Share on other sites More sharing options...
James Posted January 27, 2004 Author Share Posted January 27, 2004 Those little 4ch DMX packs, run them off a 13A plug in church halls where there isn't proper distribution, and by putting them on the bar you cut down on the TRS needed, just 13A & DMX James Link to comment Share on other sites More sharing options...
andystone Posted January 27, 2004 Share Posted January 27, 2004 Definitely sounds very dodgy, not only are safety chains not capable of taking this kind of load or, as Gareth says, suitable for a primary suspension, but they also aren't usually tested and therefore there is no actual guarantee that they will take any weight at all! General rule is that if you think something is dodgy, don't do it. Especially as you have now highlighted it, if anything does go wrong you will be the one they point the finger at. Andy StoneStagetec Link to comment Share on other sites More sharing options...
Brian Posted January 27, 2004 Share Posted January 27, 2004 A quick calculation... 6 lanterns at 3kg each2 dimmers at 1kg each1 bar at 10kg total load 30kg safety derating at least 5:1 means each suspension should be capable of supporting at least 50kg. A SAFETY CHAIN WILL NOT TAKE 50kg SAFELY. TAKE IT DOWN NOW Link to comment Share on other sites More sharing options...
Bryson Posted January 27, 2004 Share Posted January 27, 2004 Just to make it more frightening, the ABTT recommends 8:1 derating. Link to comment Share on other sites More sharing options...
James Posted January 27, 2004 Author Share Posted January 27, 2004 A SAFETY CHAIN WILL NOT TAKE 50kg SAFELY. TAKE IT DOWN NOWI don't have the rights to take the bar down. It's not my rig, It's not my job. Officially I'm just here to do sound. I am tempted to have a chat with the person responsible but I can't make him do anything, I don't want to create friction but I'm a trifle concerned. I was dubious when I saw, I don't know his kit - all the lanterns are imports - don't know the weights and came to a similar figure as you did Brian - I just wanted to be certain before approaching him. Grr. This is going to make my day SO much better. Link to comment Share on other sites More sharing options...
gareth Posted January 27, 2004 Share Posted January 27, 2004 To be honest, I think Brian's figures for lantern & dimmer weights are possibly erring slightly on the conservative side, so that makes it even worse. The fact that something else that this clown has rigged apparently fell down the other night compounds the issue even more. You have a responsibility to look out for everyone's health and safety here, James - especially as it seems that no-one else in your group is doing so. You need to speak to whoever is in charge of the venue and point this situation out to them, explain what your concern is, and ask that something be done. If you're ignored, put it in writing to the person at the top of the organisational hierarchy. If nothing is done again, a phone call to your local council to let their licensing people know might well be in order - by the sounds of what you've described, there's no way any licensing authority should permit such a contraption to be rigged over audience seating. Anything that's used for temporary suspension of lighting equipment should be inspected, rated and certified - it's all in LOLER. Safety chains conform to none of these requirements. Link to comment Share on other sites More sharing options...
ianl Posted January 27, 2004 Share Posted January 27, 2004 you say the bar is rigged on three points, assuming even distribution along the bar then over 60% of the load will act on the middle support so given the 8:1 mentioned above the points need to be rated for 160kg safety chains are definatly not for hanging loads standard hook clamps are not the way to connect rigging points to a lighting bar three points on a 20 ft bar alows no redundancy, ie the 10ft span between points is the maximum,, if one point failed the whole thing will come down you make no mention of how the top end of the chain is attached to the building which in light of what you do say I find equally worying you say something else he rigged has fallen down, someone from the venue or proiduction should (must?) investigate why it broke and will probably lead to inspecting all his other work Link to comment Share on other sites More sharing options...
Suzette Posted January 27, 2004 Share Posted January 27, 2004 I fully support Brian's statement - TAKE IT DOWN NOW (or re-rig with a safer method of suspension)Please don't let an audience sit underneath the FOH bar! Its bad enough that actors and technicians have been under it during rehearsals - let's not have another "rigging accident" headline. You say it's not your call to take it down, but even in an amateur company someone has to take responsibility for working safely. You have a duty of care to yourself and others working with you.Good luck! Link to comment Share on other sites More sharing options...
ianl Posted January 27, 2004 Share Posted January 27, 2004 if you can't / don't know how to take it down / don't wan't to touch it or whatever then I suggest you rope off a large area below it and put up a large sign saying it is unsafe and the show cannot open to the public till someone takes it down or proves otherwise Link to comment Share on other sites More sharing options...
Ellis Posted January 27, 2004 Share Posted January 27, 2004 Just a small point, but under LOLER, long link chains are not permitted for lifting. I would think that that counts when suspending a lighting bar. Forget the calculations, chains should not be used. Now that you have highlighted the fact that you know, if the bar falls on someone and you have not off-loaded your liability by informing a responsible person, YOU ave been negligent and this forum is evidence. The penalty could be imprisonment! Notify the production mamager or venue licensee in writing and get them to sign an copy as a receipt. Lock it away somewhere safe and hope that either the rigging is corrected or nothing untoward happens. My experience of amateurs is that when faced with Health & Safety, they bury their heads in the sand (we don't employ anyone, etc). Either the venue owners are employers, or they have a responsibility under section 4 of the Health & Safety at Work, etc Act. 1974. Consequently they would be my first port of call beyond the amateur company. HTH Ellis P.S. I have been there - on the receiving end of a probibition motice on Production Lighting System in an entirely amateur theatre (They spent the money on the refit then!). They cleaned up their act for a couple of years, but I left when they returned to their old ways! Link to comment Share on other sites More sharing options...
j_b Posted January 27, 2004 Share Posted January 27, 2004 Also: I forget the exact math, but the centre point of three, on a uniformly loaded bar, will be taking more weight than the end two points - it's someting like 50-75% from memory. Link to comment Share on other sites More sharing options...
Brian Posted January 27, 2004 Share Posted January 27, 2004 A SAFETY CHAIN WILL NOT TAKE 50kg SAFELY. TAKE IT DOWN NOWI don't have the rights to take the bar down. It's not my rig, It's not my job. Hi James sound like you're having fun, NOT. Whilst you might not have the right to take it down, I'm sure that you know that you have a legal duty, under the HSWA, to do something about it to make sure that somebody does takeit down or rig it proper. Link to comment Share on other sites More sharing options...
James Posted January 27, 2004 Author Share Posted January 27, 2004 A SAFETY CHAIN WILL NOT TAKE 50kg SAFELY. TAKE IT DOWN NOWI don't have the rights to take the bar down. It's not my rig, It's not my job. Hi James sound like you're having fun, NOT. Too right not having fin today (as other post mentions in "today I'll be" thread...) Basically have chatted with guy responsible and he has commented that he normally uses steel chain that he couldn't find this time, and "well the cables would catch it anyway" and "it will only fall if someone swings on it" and the carp sugested "we could always tie it off with a bit of string" (Well I hope he meant sash cord.. ) anyway the bar is now suspended by 7 chains now not 3 - though they all are standard safety chains. And whilst I'm still not happy it's rigged to safety standards I do not think it poses a significant risk to anyone anymore. (Though I'm tempted to take a photo tomorrow....) James Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.