Aerialists on chain motors?

[top-cat]

If it does, surely the best option is to bypass the motor with a steel. Of course, how practical this is would vary depending on your situation.

 

It's not practical in any respect because it's totally unnecessary and pointless!

 

Hence I don't think it even says that anyway. I think Kerry (with no disrespect) made that up. The point about people, yes. But leaving loads unattended? No. There is no reason that an unattended load is any more dangerous than an attended one... if anything, if something falls down in an unattended environment it is by the nature of nobody being there, significantly less likely to hurt somebody.

[paulears]

There's a postscript to this. The aerialist came to say thanks as we were packing. Clare, my RADA trained stage manager pointed to the label on the end of the motor, he read it, and looked very unhappy. Is that what was holding me up? We nodded. Was it safe? We said we believed so. He then asked why the label was on the device. We didn't really have an answer for that one. He explained how much the actual straps and package he was using cost, and how strict the supplier had been on having them regularly inspected for safety, and he'd simply been told the people doing it were experienced. He trusted the producer. He didn't look that trusting after seeing the label. While packing away the kit we found a case of various length steels, and shackles - the usual rigger stuff. Surely with these they could have rigged a much simpler system? It's making me think for the future.

[kerry davies]

Page 11, Safety Procedures, Item 6

I take great exception to being accused of lying but it is important that you have. Unless those using the equipment know what is in the MIs and can justify deviating from them they should not use that equipment. All MIs stipulate training and/or "read and understand the operating instructions".

 

Just in case anyone thinks this is a strange anomaly; See here.

and Item 4.2.3 here. All chain hoist MIs, manual or electric, say the same.

 

Chain hoists were designed for raising loads and not for suspending them and Seano will know more about the moves to redesign them for use in our industry such as;

...higher integrity hoists which do not require secondary suspension systems to hold the load in the event of a failure. These include equipment to the British Standard BS7906: Part 1, Category A, and BGV D8 Plus and BGV C1 German safety standards.

 

Paul, thanks for getting back to us. It surprises me, and will irritate Tom, that an aerialist doesn't have a lot more input into their own rigging safety. Let's get one thing clear now, I genuinely don't care if someone has taken an informed, intelligent, competent decision to deviate from MIs. What gets right up my nose is when people do so in an ignorant, unthinking, inept manner. Your action in pointing the warning label out to the aerialist is to be commended. Now they can go away and make that informed decision.

Ignorantia non excusat.

[djw1981]

Asking as a non rigger, from an information point of view.......

 

If youraise a truss on motors, then put steel fixings on, such that if a motor fails, these steels (safeties?) carry the weight, would that be permisible, since the motor is not carrying the whole weight?

[top-cat]

Page 11, Safety Procedures, Item 6

I take great exception to being accused of lying but it is important that you have. Unless those using the equipment know what is in the MIs and can justify deviating from them they should not use that equipment. All MIs stipulate training and/or "read and understand the operating instructions".

 

 

Just in case anyone thinks this is a strange anomaly; See here.

and Item 4.2.3 here. All chain hoist MIs, manual or electric, say the same.

 

 

Not so much lying as being mistaken.

 

That is not the type of Lodestar which we use in the entertainment industry. We use this type of Lodestar and there is no such warning. You are referencing industrial hoists, which are built to different standards, and feature different systems for safety and for control. Entertainment hoists are built in light of the unique requirements of hoists in the entertainment industry that differ to or are not applicable to industrial lifting needs. Thus, some of the practices for using such equipment does differ.

 

 

Chain hoists were designed for raising loads and not for suspending them and Seano will know more about the moves to redesign them for use in our industry such as; ...higher integrity hoists which do not require secondary suspension systems to hold the load in the event of a failure. These include equipment to the British Standard BS7906: Part 1, Category A, and BGV D8 Plus and BGV C1 German safety standards.

 

There is no evidence to suggest that chain hoists are not designed for suspending loads. In fact, the description given to BGV-D8+ hoists is along the lines of "for suspending, but not lifting, loads over people without secondary suspension". That sounds pretty conclusive to me.

 

The standards you refer to, yes these are coming into play but to be honest, most companies already have systems in place that they are not hugely influential at this time.

 

There is a good guide HERE, the table on Page 2 simplifies things somewhat. The basic outlay is with reference to protecting a load from failure of the hoist.

The 'basic' hoists, generally "BGV-D8" and "BS-7906 Cat B" hoists, have less safety features to protect the load. The safety factor is 4:1 or 5:1, and there is no requirement for electronic limits (to prevent the hoist travelling beyond a set point on the chain), encoders (for electronic positioning data of the hoist), load cells (for electronic monitoring of the actual weight loading on the hoist), double brakes, etc.

These standards escalate through "BGV-D8+" and "BS-7906 Cat A" hoists, with improved safety features - IE electronic limits, double brakes, and higher safety factors; which permit the hoists to suspend loads without secondary suspension (IE 'safetys') over people. A

nd then again to the "BGV-C1" standard for lifting over people. One of the main differences with the C1 system, over BGV-D8/+, and BS-7906, is that BGV-C1 requires a system of lifting equipment, where the entire system is classified to BGV-C1. So you would need a hoist and a controller, working as a complete system, and certified as such a system. They're not 'mix and match' compatible, whereas a Cat A motor plugged into any low voltage motor controller will still be a Cat A compliant hoist.

 

 

All that aside, it has not really had to take hold too much in the industry thus far. Most touring hoists are still just a standard D8 / Cat B spec, single brake hoist. The need for a secondary suspension can be achieved by use of another motor, so that failure of one hoist is backed up by another. (And this is supported in the CM Manual). It is far easier for your major lighting companies to simply send out more hoists on the tour, than it is to have to completely replace their motor stock with upgraded hoists. Additionally, some arenas, theatres and venues still insist on safety steels / chains, regardless of the type of motor used. Often the de-facto standard is to safety all the trusses over the audience, even if they do have many motors on the truss; but over-stage can be on hoists alone.

 

There is also still something of a lack of clarity over which specification we work to (do we work to BS, because it's British? To we work to the German, to keep things universal? What do we do in France? What do we do for American tours bringing motors over?) It's all a bit hazy, and so using systems of work like I have given examples of above helps to ensure compliance without having to worry which rule you are supposed to be following. However, that may be subject to change in coming years as insurers get hold of the regulations, and place their own demands on their policy holders about kit compliance. Last year I fitted some BS-7906 Cat A hoists into a venue supporting a truss over the entrance hall, because the insurance company demanded that it be done. So I do think there is scope for this to happen. But at the moment there is a fair bit of freedom, and generally, if you were doing it safely before, you should be able to keep doing what you were doing without anybody interfering.

 

My personal stance in my rigger shoes is that using a D8+ or a C1 hoist or whatever, only reduces the chance of a hoist failure. It makes no change to a SWR drift or a spanset failing. Neither does it mean an eyebolt can't be pulled out of the roof. These are all still points of failure that could cause catastrophic loss of your load if they fail, regardless of the safety standard of the hoist. So in my mind, secondary suspensions - whether that be motorised, or static - are still important to protect against all possible points of failure.

 

Paul, thanks for getting back to us. It surprises me, and will irritate Tom, that an aerialist doesn't have a lot more input into their own rigging safety

 

Question is, is there any need?

 

I doubt Mick Jagger had much input into the safety of the lighting truss flying right over his head. But had that failed he'd have been brown bread much the same as an aerialist's suspension failing. Personally, I don't see anything wrong with the system of it being left to a competent professional to do this, and the aerialist to trust their word and their actions. And the aerialist gets to select their rigger, and work with them every day. Every time you set foot in an elevator, you're putting your life in a bloke you've never met, whose training and competence you have no idea of; and you just accept and trust that the lift operator is making suitable safeguards to ensure it is serviced and maintained properly. It's just a fact of life that day to day we do place our safety in the hands of others, and trust them on their actions.

 

While packing away the kit we found a case of various length steels, and shackles - the usual rigger stuff. Surely with these they could have rigged a much simpler system? It's making me think for the future.

 

Actually fibre rope could be a perfectly good option. It's too often overlooked, but good fibre rope can be very valuable as it runs cleanly through rigging and is still very capable of taking large loads. Dyneema is gaining popularity in performer automation and in many instances can be stronger than steel drifts of the same diameter.

 

I think the main reasons somebody would choose to use a motor over a static suspension with some kind of hauling line to pull it out of the way, would be because they don't have a suitably placed person to do the pulling, or there is nowhere available to pull it up to due to the placement of scenery / other rigging in the fly tower. The nice thing with a motor is that it does a simple straight line pull in a compact space, and can be operated with a button press anywhere on stage. As Seano rightly pointed out, beside all safety notes and manufacturers instructions, I would have thought the main disadvantage was the slow speed of a 4m/min motor chugging away... with a 12m pros that's 3 minutes to have it from floor to out of sight! They're also a bit noisy, even quieter motors can have quite loud brakes, the 'classic' lodestars certainly do. A simple hand line would be both faster and quieter.

[Stuart91]

There is no reason that an unattended load is any more dangerous than an attended one... if anything, if something falls down in an unattended environment it is by the nature of nobody being there, significantly less likely to hurt somebody.

 

If a truss falls in an unattended venue, does it make any noise?

[Seano]

Paul, thanks for getting back to us. It surprises me, and will irritate Tom, that an aerialist doesn't have a lot more input into their own rigging safety. Let's get one thing clear now, I genuinely don't care if someone has taken an informed, intelligent, competent decision to deviate from MIs. What gets right up my nose is when people do so in an ignorant, unthinking, inept manner. Your action in pointing the warning label out to the aerialist is to be commended. Now they can go away and make that informed decision.

Ignorantia non excusat.

 

I'm also a bit surprised (actually not all *that* surprised) the performer was not more aware, but I'm not with you on the leap from that to the decision being ignorant, unthinking etc.. Ain't necessarily the case. The aerialist didn't make that decision, clearly, but to be honest he sounds like a bit of a balloon to me anyway.

 

Asking as a non rigger, from an information point of view.......

 

If youraise a truss on motors, then put steel fixings on, such that if a motor fails, these steels (safeties?) carry the weight, would that be permisible, since the motor is not carrying the whole weight?

 

Perfectly sensible question, but asked 30 years or more too late. The issue of when and whether to bypass hoists with secondary suspensions (so-called "safeties" indeed) has been a topic of discussion whenever two or more riggers were gathered around with nothing better to talk about since the idea of putting super duper extra long chains on factory chain hoists and using them upside-down was first hit upon. (And a topic of discussion among elf'n'safety types since the decline of the traditional jobsworth's peaked cap in favour of the spotless hi-vis and shiny white hard hat.)

 

Policies have been written and wrangled over, and practice has varied from 'nothing, ever' (throughout most of the USA) to 'everything, always' (most of Germany) and almost the whole spectrum across different regions of the UK depending largely on the local authority, or even between one London borough and another.

 

Not so much lying as being mistaken.

 

That is not the type of Lodestar which we use in the entertainment industry.

 

Its you who are mistaken, it is indeed the same machine. Hoists designed specifically for the 'entertainment industry', and the standards they're designed to meet are a surprisingly recent thing.

[kerry davies]

I see Bishop Berkeley has joined us, Hi Stu.

May I remind everyone again that this was all about an aerialist and a single chain hoist. Can we all agree that chain hoists should not be used to lift or suspend human beings according to MIs? That seems plain and then Pageii, before the page TC quotes, says; "Tie off the load with auxiliary chains or cables before access to the area beneath the load is permitted."

 

Following which; "As an alternative, the system may be designed such that malfunction or failure of one hoist’s load bearing components does not cause load loss and/or overloading of any other hoists in the system. Note that in such a system, hoist performance and function must be monitored visually or with use of load cells"

 

That, to me, says exactly the same as; "DO NOT leave load supported by the hoist unattended unless specific precautions have been taken."

 

This is NOT about what we do, it is NOT about if it's safe. It is about having the capacity to stand in a court of law and to justify failing to follow written instructions. The overhead suspension of a human being by means of a single, non safety chained electric chain hoist is specifically forbidden in the written and published Manufacturers Instructions on two separate and individual counts.

 

This has been the history of our industry. We adopt and adapt existing tools and eventually have to re-design them to our own requirements. Until CM re-write their entire MIs and operator's manuals we are stuck with it. One final word and I apologise for swearing in advance, Tallescope.

[top-cat]

Not so much lying as being mistaken.

 

That is not the type of Lodestar which we use in the entertainment industry.

 

Its you who are mistaken, it is indeed the same machine. Hoists designed specifically for the 'entertainment industry', and the standards they're designed to meet are a surprisingly recent thing.

 

Then why do the 2 have 2 different manuals with 2 different sets of precautions to deal with?

 

Whilst the chassis and mechanics may be the same, they're sold as different products and the manufacturer's instructions for each differ. That's all.

 

And how do you explain BS-7906 "Use of lifting equipment for performance, broadcast and similar applications. Code of practice for installation, use and removal of above stage equipment (excluding trusses and towers)" which is 14 years old now (not particularly recent)?

 

 

Following which; "As an alternative, the system may be designed such that malfunction or failure of one hoist's load bearing components does not cause load loss and/or overloading of any other hoists in the system. Note that in such a system, hoist performance and function must be monitored visually or with use of load cells"

 

That, to me, says exactly the same as; "DO NOT leave load supported by the hoist unattended unless specific precautions have been taken."

 

I agree, hence as per my whole underlying point, the most important thing is that all rigging work is undertaken by professional and competent riggers who are able to decide what those specific precautions are and if they have been met.

[Seano]

My new phone came with several different manuals. I went back to the old one in the end, it was just too complicated. Who has time to learn all those different languages?

[bigclive]

I have to admit that if I was a chain hoist manufacturer I'd be quite worried about the liability aspect of one or more people being suspended from a single hoist. In the case of a truss a single hoist failure would be much less dramatic than a group of people hanging from some metalwork crashing to the ground in a situation that was being filmed simultaneously from a veritable gaggle of camera-phones.

 

Perhaps I might word the label to imply that the hoist shouldn't be used as the single point of attachment, but for bringing something like that in and out during a touring show it could get quite complicated.

 

This gets even more complicated when the performers are actively spinning their performing rig on the chain or swivel.

[ImagineerTom]

I'm going to express concern about the aerialist in question here simply for him being an idiot. The "standard" training is that you either test/check everything you're hanging from yourself, or you use a rigger/rig designer who you personally trust (literally) with your life to create and instal it for you. To go hang from kit you've not checked, put up by someone you've never met before in a venue you don't know and just blindly trust it's all "ok" is just plain stupid.

 

T

[top-cat]

To go hang from kit you've not checked, put up by someone you've never met before in a venue you don't know and just blindly trust it's all "ok" is just plain stupid.

 

 

Never was a truer word spoken.

 

Although people do it every day with bungee jumps!

[Brian]

The thing is, none of this 'not to be used for lifting people' has anything to do with engineering, physics or science. It a commercial decision driven by the cost of the manufacturer's Product Liability Insurance. Independent testing of a product, which their insurers will want, is expensive. Very expensive. I'd not be surprised if a chain hoist cost in excess of £50k to test for each standard you want it certified to. And if you nave a range of products, say with different load ratings, each one will need testing. Different products for different markets? That's a different set of tests for each market.

 

It's a very common scenario. All semiconductor manufacturers prohibit the use of their products in life support equipment. Many manufacturers of power supplies prohibit the use of their products in medical equipment. And so on. The self same product can often be bought as a general purpose unit or as a unit for medical use. There is no difference in the actual product; all that the medical one has is a different sticker and the appropriate insurance certificate in a folder somewhere.

[Jivemaster]

Remember also that aerialists are chosen from the best looking cute dancing girls, NOT for their paperwork and admin skills and their knowledge of H&S legislation in every country they may visit for a day or tour.