The use of Safeties

[Rob]

Moderation - Topic split from "Roundslings" thread

[ag_lx]

I'm not a rigger, so don't want to comment on issues raised, but I am a medic and so would like to comment on a few of those points raised.

 

If someone is not breathing, they won't actually die at the four minute stage. This is when the lack of oxygen starts to affect the brain - starting to cause brain damage. People can be not breathing for quite a long time and be successfully resuscitated with out too much long lasting dammage. However, that is not always the case.

 

The faster breathing can be resumed, the better the chances of survival. Loss of blood causes problems in the long run, but loss of breathing causes problems in the short run. You want to be breathing!

 

An incident was mentioned where a rigger was being immobilized to protect his spine, but complained that he could not breath. The priority is always breathing. What use is a perfect spine if you are dead? Far better to have paralysis but be alive. If you need to get them in the recovery position - and if they are unconcious then you will - try to get enough people (4-6) to log roll them as this will help protect the spine. If this is not an option then don't hesitate to get them in the recovery position the normal way on your own. They wont blame you if you do damage their back, but will thank you for saving their life.

 

 

Aleksis

[Chris Higgs]

Trusses are lifting accessories, technically 'seperate lifting accessories'.

 

To stop a load generating a force, you obviously need to stop it falling far. Recent work with a firm of international consulting structural engineers suggests about 150mm to be the maximum.

Any secondaries need to be that tight.

 

Copying what you see is precisely how many people learn, it certainly wasn't intended to be critical for the sake of it. My comment about excuses is because I have too often heard the argument that secondaries aren't needed. Trouble is the process by which this decision was arrived at was not accurate or informed. I suspect many people would change their minds when the actual facts of a situation are discovered, revealed or presented. I did.

I can only offer the experience of the last 30 odd years, advice I have been given, the detail I have then researched and legislation I have been trained in.

[Chris Higgs]

Re suspension trauma.

See the thread 'Nix revived.

It's not the breathing, it's the circulation. This has been researched and the HSE research document is available on their site.

Rapid release and using the recovery position following prolonged suspension is potentially fatal.

Studies have shown that 87% of people will pass out in less than an hour, 10% within 10 mins simply by being suspended, no fall, no injury.

That's why when unconscious, it is imperative to get people within reach of a paramedic or similarly skilled person within 15 minutes.

The shortest period from unconsciousness to death in such circumstances is reported to be 6 minutes.

 

The Work at Height Regulations come into force tomorrow. Rescue planning, training and equipment provision are specified.

[Nick Evans]

The introduction of trusses as a justification for safeties clouds the issue. If safeties are used to protect against truss failure, surely these need to be placed between the points rather than at the points, since if the safeties are at the points (protecting against motor failure) there is no protection should the truss fail at some point mid span.

 

We are in danger of creating a position where it will become impossible to tour in the UK because of legislation being applied to the industry. At present, as I see it, it is not possible to climb on a truss in Wembley Arena without there being 2 standby rescue technicians on hand. Since a truss has holes big enough to fall through it can it be considered a work platform? Or will lampies now have to be rope access trained in order to traverse a truss? On most stages access equipment such as aluminium towers or tallescopes are not practical because they cannot be stored nor can they be used where there are risers and backline in the way. Such towers would also have to be inspected before use by a competent person. If mechanical access is specified as the means of rescue it must be contiuously available at all times including when the audience are in if truss spot operators are to be used. If no such access is available does this mean that no maintenance can take place? If the promotor fails to provide adequate mechanical access, does the show get pulled? Climbing on trusses is part of the job of a touring lampy or rigger. The less familiar they become with the task the more likely they are to have accidents.

 

No statistical evidence has been presented which proves there is a risk of a motor failing once the load is at trim (ie when it would be safetied). If a motor is going to fail I contend that it is during the rigging process that it will do so, as the load is applied (whilst things get rigged) and the dynamic load of stopping and starting is being applied.

Furthermore, it is my contention that in the touring environment the application of safeties is an unneccasary exposure to further risk since:

a) local riggers have to sit around for long periods waiting to safety loads, reducing their rest period,

b) it prevents the truss or other load being lowered for maintenance purposes (see Work at Height Regs)

(2) Every employer shall ensure that work is not carried out at height where it is reasonably practicable to carry out the work safely otherwise than at height.

and

c) that dropping a truss in is a valuable aid when rescuing a suspended casualty.

and that none of these factors were considered by local council licensing inspectors when safeties were first introduced.

[j_b]

Climbing on trusses is part of the job of a touring lampy or rigger. The less familiar they become with the task the more likely they are to have accidents.

 

c) that dropping a truss in is a valuable aid when rescuing a suspended casualty.

and that none of these factors were considered by local council licensing inspectors when safeties were first introduced.

<{POST_SNAPBACK}>

 

 

The less familiar they become, the more careful, and less blaze they will be.

 

What about the use of inertia reel arresters as a secondary? These would allow the truss to be lowered in the event of an accident, or a deliberate, without and unnecessary work at height, i.e. 'going up and taking the safeties off'

[Nick Evans]

j_b

Whether or not a person is blasé is entirely down to that individuals state of mind, and less to do with experience. The more practice one has at a task the better that person becomes at executing it. The logical conclusion of your argument is that a person with no experience whatsoever is less likely to have an accident than someone with years of experience. There are experienced people who are cautious, and experienced people who are not.

 

Inertia safeties would work fine in a permanent or semi permanent environment, and other posters have alluded to them being used in some venues already (though the type of production was not mentioned). A venue which stages touring events has points going up in different places every day, and so a venue would need to either have enough inertias to cover all events or they would have to be movable (this would probably be practical where there is a mother grid I would think). I am not sure if the issue of liability means that the touring production would need to provide the inertias or not, but if they did then these would have to be rigged every day, doubling the amount of work (and therefore exposure to risk) that takes place in the roof.

 

The thread regarding suspension trauma is very interesting, I knew there was a risk but was not sure what it was nor what the physiological reasons for it. The fact that suspension trauma exists does not detract from the point that brain damage may begin to occur within 4 minutes if the casualty is non-breathing, and that it is not possible to assess a casualty from the ground in order to decide whether or not the rescue may be delayed.

[dtgorton]

In short then, as this is a massively rambling post; 

1) we do our RA to weigh up hazards, severity & probabilities 

2) it seems reasonable to me to safety off complex components that we cannot verify for ourselves 

3) I wouldn't move trusses with unconscious people on them

1) based on what data?

2) If data supported the contention the device was extremely unlikely to fail this becomes uneccasary and does not allow for the implied risks incurred by using safeties

3) I would if it was the most practical way of rescuing someone. I would also expect my colleagues to do so if I was the unfortunate.

 

In response:

1) One carries out one's RA based on all available data, and yes, drawing on one's own experience. However, it is my belief that, in the event of any incident, it would have to be a remarkable case for the HSE to take one person's experience over documented recommendations from the manufacturers, e.g. if the manufacturers state categorically that safeties should be applied, then that seems pretty clear cut to me.

 

2) Yes, I agree with you on this, almost despite what I've written above. In a previous place of work we worked to a 75% redundancy on motors, i.e. if a 1t motor could be shown to be lifting no more than 250kg it didn't require a safety. Bizarrely enough, this did happen often enough to be worth doing the calcs for. Most often it was things like a projector / screen truss on 2x 1t motors. Total load ~250kg, => 125kg ea, plus, if one were to fail completely we'd know a) the other motor could take full load, and b) the truss swinging down would be still well clear of any obstruction, human or otherwise.

 

3) Hm, after some reflection, I find myself partly agreeing with you here too. If it was clear that running the truss in would be the fastest & safest way, with absolutely no chance of making the situation worse, then yes I could foresee myself doing this. But my first choice would be a 'picker, every time. But again, one has to weigh up the risks and act accordingly.

 

Just to briefly address a point raised by Chris Higgs re EC grid, yes, there is a rope access technique to rescue fallen casualties, to put this into practice would take ~10min. It is a condition of work at height in the venue that there always be a secondary method of rescue when someone is aloft, e.g. >1 'picker, rope access, truss ladder, etc. The first choice of the venue is still to have a 'picker on standby, and this is operationally the case for all load-ins / outs. Fortunately the space available, coupled with some effective management, meant this is almost always possible even on the big / complex shows.

 

Dave G

[j_b]

these would have to be rigged every day, doubling the amount of work (and therefore exposure to risk) that takes place in the roof.

<{POST_SNAPBACK}>

 

Doubling the work compared to not fitting any form of secondary I agree, after all, the word secondary means "2", but compared to fitting for example a steel with a 20' stinger, yes, the inertia reel is heavier, but I wouldn't say doubling the work.

 

Many venues have a catwalk type arrangement, which is often a reasonably safe place to work at height from - acces by stairs or lift, decent floor and handrails. This is an excellent place to be fitting inertia reels from, as oppose to climbing round a motor on top a piece of a-type carrying this & that. Equally, rigging the gear from a MEWP whilst the stage is clear is another method of lower risk work.

 

Therefore, the risk can be reduced, providing a safe method of work is chosen.

 

Becoming blasé is down to state of mind, I agree, and I have seen *lots* of people learning to work at heights. They all start of careful, cautious and steady, but many 'change their state of mind' as they get more experienced, and hence become blasé.

 

I did.

[Nick Evans]

j_b

When I said the work was doubled, I meant that twice as many points need to be pulled up. I actually prefer pulling up chains to inertias, the stinger may be longer but the last bit of the pull is heavier IMHO.

Many venues have a catwalk type arrangement, which is often a reasonably safe place to work at height from - acces by stairs or lift, decent floor and handrails. This is an excellent place to be fitting inertia reels from, as oppose to climbing round a motor on top a piece of a-type carrying this & that. Equally, rigging the gear from a MEWP whilst the stage is clear is another method of lower risk work.

All true, however the catwalks have to be in the right place with respect to the load to be protected. Obviously it is easier and safer to rig from a picker, however as I have outlined in previous posts, there are many occasions when mechanical access is not available.

 

Experience may give some people a misplaced sense of confidence correct. Practice, and maintaining currency are good things, hence why other posters have alluded to rehearsing rescues periodically. The more someone does something, the better they become at achieving the task, the less likely they are to perform the task wrongly. This is why we have rehearsals, and pilots have currency requirements, and people go on first aid refresher courses (amongst other reasons). Someone who drives more frequently has better basic handling skills than someone who drives once a year. Therefore I think the statement

Climbing on trusses is part of the job of a touring lampy or rigger. The less familiar they become with the task the more likely they are to have accidents.

is justified.

1) One carries out one's RA based on all available data, and yes, drawing on one's own experience. However, it is my belief that, in the event of any incident, it would have to be a remarkable case for the HSE to take one person's experience over documented recommendations from the manufacturers, e.g. if the manufacturers state categorically that safeties should be applied, then that seems pretty clear cut to me.

I believe such indications to be in response to product liability laws in the US and other places (Interestingly, in the US there are probably 30 or 40 large tours loading in and out every day, probably upward of 1000 Lodestars being rigged every day, and not one safety, but the use of horizontal lifelines and fall arrestors has been compulsory for years. But then again, they still don't have tachographs so who are they to tell us anything)

 

2) Yes, I agree with you on this, almost despite what I've written above. In a previous place of work we worked to a 75% redundancy on motors, i.e. if a 1t motor could be shown to be lifting no more than 250kg it didn't require a safety. Bizarrely enough, this did happen often enough to be worth doing the calcs for. Most often it was things like a projector / screen truss on 2x 1t motors. Total load ~250kg, => 125kg ea, plus, if one were to fail completely we'd know a) the other motor could take full load, and b) the truss swinging down would be still well clear of any obstruction, human or otherwise.

There is no logic to this (it is a pragmatic approach however). Motor failure does not have to be related to load, if a component works loose there is no saying whether or not it will only fail at high load or whether it will fail at any load. If the projector cradle were to fail, I refer you to your own statement regarding the HSE. What happens when someone runs another truss down onto the unsaftied one? In my ever so humble, I think that omitting safeties on lighter loads is tacit admission that safeties are not required.

[Chris Higgs]

The original contention was that secondaries meant people were at unnecessary extra risk.

As someone who has spent many, many hours over many years 'waiting' to put safeties on, I still disagree; that was part of my day and it was done.

I worked it so it could be achieved without fatigue. I quite agree that it also means that recovering someone that has fallen is more problematic BUT should they be in that situation in the first place?

I recall a tour in the mid 80's where the (American) crew used an electric winch to get lighting crew up on the (catwalk) truss. I remarked that this was an unusual luxury which was met with "Hey, we don't risk our necks".

They weren't using secondaries either; they had a flip-box truss system with a lot (and I mean a lot) of hoists on it. If a point had failed, I doubt anyone on the catwalk truss would have even noticed. That is a very different picture from, say, a two motor front truss in a civic hall.

 

The issues surrounding the need for the extra security afforded by either a secondary or other means are another matter. Personally, I would always prefer an independent secondary, but I would also prefer to access everything by machine where possible, so in that case falling from the truss/rescue scenario is irrelevant, too.

Don't forget LOLER specifically requires the use of additional measures when suspending loads over people. I don't think that will ever mean just the crowd.

I remember having it explained to me thus: the act were employees and the system was part of their work environment so they were insured to be under it, but the billies weren't. Even if it were the case then (I would have had no idea what the law said then, the HaSaWa had only just come into force in any case) I doubt it is now.

 

I am more particularly keen to avoid statements such as 'climbing on trusses is a lampie's job'. It may be currently, but we should do all we can to reduce the need. There are many venues/productions that could provide access, there are many forms of access that are available. Of course there are problems such as cost, space and manpower to provide and use it which will take a long time to overcome, but we need to help the process along by not accepting the fact nobody has specified the job/venue/kit properly or with regard to the law, depending on your perspective on it. They are the employers, after all. Let's not get into the "Ah, but I'm freelance" again...

The managements of venues are also partly responsible for what goes on in their premises, and to ensure along with the employers of the people doing the work that the risks taken equate with the importance of the task being undertaken. Focussing etc. does not equate with loss of life/serious injury, etc..

But of course the task is essential to the production. A dilemma.

 

The fact is not many people do fall or are injured (as far as we can tell) at present, but if it did occur, one would be in trouble if unable to justify the way work was being done.

If someone had been injured or worse, it wasn't a safe system, was it?

 

If the truss spans and loads are (say) half that allowable and they are rigged on several de-rated motors, I would be the first to agree with leaving the load on motors only to assist in rescue (along with an emergency stage clearance routine) and, as quoted, in assisting maintenance.

That was not the original tone of the post.

 

The Work at Height Regs also specify work at height should be carried out safely.

At the risk of criticism because of my association with the T2 system, most of the trusses on the market are not designed to sustain fall arrest loads when used to carry loads (such as lights) at the same time.

The 6kN that may be generated by a fall on a 2m lanyard with an energy absorber may be enough to cause a local failure on the truss precipitating the progressive collapse of the truss. It depends on how and where the load is applied and what else the truss is doing.

There are ways of engineering the truss to cater for the load created by a horizontal line, but not many people do it. There are ways of reducing the forces by using particular types of lanyards, but often that is overlooked, too.

 

Often the manufacturer will specify the anchorages to be capable of sustaining of 10kN (1000kgs) or more. That could rip bracing members out of a truss.

Several years ago, I spoke to Crosby at a trade show in the US and they agreed rigging a pear ring under the hoist to take the truss sling and then connecting a horizontal 'safety' line to it at right angles was not a good idea. Running the line through the ring and then down to the bottom chords at a node point, maybe a little better but even then it needs careful evaluation with respect the other loads carried by the truss. Same can be said of inertia reel fall arrest devices.

 

I fully agree with the statement about practice meaning accidents are less likely, and one could make a case to support that in health and safety speak, BUT there many associated factors that also need to be in place to make it a "safe system of work".

[Nick Evans]

Fatigue is an issue in many many industries and has been recognised as a primary factor in many accidents outside entertainment. Promotors, who book riggers, do not at present have in place any policy whereby fresh crew are provided for a load out, and there are financial disincentives for them to do so, as well as practical considerations from production's point of view. Until this is addressed we will continue to see people who have been awake for 16 hours going up into the roof to do a load out. Furthermore, I think it is highly likely we will continue to see local riggers driving around following tours to nearby (or not so nearby) venues. Whether this is legal, or defensible etc in theory is irrelevent because it will continue in practice. The more and more that climbing is deemed verboten the longer the safeties stay off, if this is the only way of getting the lights back down. The longer the riggers are in the building.

 

Not having to fix safeties to a rig would mean that local riggers could leave load-in earlier and be called later to a load out. This increases the oppurtunity for rest.

 

Not safetying a truss gives another option for rescuing fallen casualties.

 

Safeties have been and continue to be a factor in human error incidents, generally when a flown structure is run down onto them or a descending structure becomes entangled.

 

Any logical argument depends on data, and there appears to be no data specifying the risk of a motor failing when a truss is at trim. Perhaps the industry should be researching this. It should be easy enough to catalogue known accidents, decide into what catagory they fall and extrapolate statistical evidence from said data. This would seem to fall under the remit of bodies such as the PSA. (Of which, yes I was a member for the first 4 years). Until there is empirical data and proper statistical analysis all arguments are merely points of view based on incomplete data and life experience.

 

What evidence is there that a derated motor is any less likely to fail?

 

There would appear to be very little health and safety legislation which is specific to rigging in the entertainment industry. Instead we are handed legislation which appears to generic or aimed at the construction industry. Many other industries have argued for exemptions to certain H&S legislation, farmers, fishermen, doctors, climbers and divers have all been given certain dispensations regarding aspects of their activities. We seem to be beholden to a nanny state which seeks to restrict the ability to work beyond practical means, if we took the HSE at their word we would not be able to stack boxes in trucks anymore, because they are too heavy. Does this mean we have to contemplate flat packing trucks via loading docks and doing any lifting with a forklift, because thats how Argos do it?

 

I foresee the day when productions will cut elements from shows simply because they are no longer practical due to excessive legislation (wandering slightly off topic) and therefore productions will require fewer crew and be less imaginative. Lights which are broken will stay that way because there is no practical access to get them down. Large moving scenic elements will be cut because there is no way of getting at the working parts once they are up, and without the ability to fix them they become too much of a risk to the whole show. (As an example, the last tour I did would have not required my colleague and I, because the artist flying would have been a non-starter, and no-one would risk the complicated system of drapes we used because failure of any system would have seriously curtailed the show. We played many hockey arenas in America, almost all of which have no access for large plant once the stage was built, and as the auditorium was all seated there was no access from front of house either. In Europe there was agreat deal of the old East in some very interesting places, the chance of getting reliable mechanical access being very slim)

 

The original contention was that secondaries meant people were at unnecessary extra risk.

and I stand by that. Unneccasary; if the motor is extremely unlikely to fail. Extra risk; the more time someone spends at height, the longer the exposure period, the greater the risk. The fewer the number of rescue options, the greater the risk. Where there is no other access, and climbing becomes part of the maintenance function, the greater the risk. It is a question of balance. Obviously I am sitting on the other end of the see-saw.

[Wilf dLampy]

We seem to be beholden to a nanny state which seeks to restrict the ability to work beyond practical means, if we took the HSE at their word we would not be able to stack boxes in trucks anymore, because they are too heavy. Does this mean we have to contemplate flat packing trucks via loading docks and doing any lifting with a forklift, because thats how Argos do it?

<{POST_SNAPBACK}>

This raises an interesting point. The use of trucks to carry large amounts of equipment must be much higher in the commercial- shop-supplying industry than in entertainment. However (on the whole) the supply industry has adapted packaging and delivery methods to the rules set out by the HSE and other bodies. If they're doing so much of it so regularly perhaps the entertainment industry should follow their lead. Maybe equipment doesn't have to be shipped in the manner it currently is.

 

This then goes full circle back to the rigging issues of this thread. I'm sure other industries that use hoists, suspended loads etc have adapted their working practice to make things safer, and on the whole the entertainment industry has (from a personal point of view every event I've been involved in over the past few years as used a secondary support suspension from the roof to a truss). The "safety" isn't only there in case the motor fails- it's also there in case any other part of the support mechanism fails, everything between the roof support and the truss. For example unseen damage to a roundsling or chain, a loose shackle pin etc -yes, all these things must be checked beforehand but accidents do happen- having a secondary means that if any of those occur, it is MUCH less likely to cause death or injury.

 

Oh, and personally I really like using inertia steels as a secondary where suitable as they are so easy to rig and derig. Once the rigger is in position putting in a motor point it is a short procedure to add in the block at a nearby suitable location. If a rope was used to lift the block to the ceiling, the end can be tied onto the steel and it can be extended to the truss on the ground. It also helps reduce the risk of accident during the raising and lowering of a truss.

[Nick Evans]

Wilf,

 

I think there are many practical differences between retail distribution and touring transport, first and foremost in entertainment there are a great many heavy items. At present, there is no way of flightcasing a socapex loom of reasonable size and comply with manual handling regulations. There are very few circumstances when I would not tip Gladiators or Supertowers in a truck, they take up too much room on the floor. Whilst it is possible to stack lighter items on top, this involves a lot of pushing and shoving in a confined space, and my own experience is that this is when one is most likely to damage oneself. Truss can be stacked horizontally but this requires a great deal of handling in the truck, whereas if it is stacked on end it is easier for the crew to load the truck, and it is faster. Retail distribution companies are only ever transporting the same thing, e.g. pallets or trollies, that is they are designed for a purpose. Meat racks and set carts are an attempt to do this. But when you come to load the rigging truck, there is very little that can be easily lifted, the truck may well be loaded to its gross weight and there will be stuff stacked. The trucks are packed according to the order stuff is required in the morning and when it becomes available during the load out, not by sorting it into the best loads from the perspective of lifting things.

If they're doing so much of it so regularly perhaps the entertainment industry should follow their lead.

This seems to be a regularly expressed point of view, personally I think the entertainment industry should be providing the lead on issues directly related to entertainment, rather than accepting legislation which may well be general in nature or worse still, aimed at a different industry which operates with different operating parameters.

If they're doing so much of it so regularly perhaps the entertainment industry should follow their lead.

I am struggling to think of an industry which uses lifting where steel wire rope is used as a secondary in the way we use it.

Oh, and personally I really like using inertia steels as a secondary where suitable as they are so easy to rig and derig.

Not sure about that. Firstly, it is another point, it takes just as long to pull up as a chain. The last time I used inertias they were 1T SWL and weighed 35kg, so the last 15m of the pull was about 39kg straight lift, and not fun. If the point is a bridle, don't you have to bridle the inertia as well?

If a rope was used to lift the block to the ceiling, the end can be tied onto the steel and it can be extended to the truss on the ground.

I am sure I have misunderstood this, but if you tie your rope onto the inertia, how do you pull up the next point? If you had 20 points to pull up (and 20 inertias) do you take 20 ropes up? Personally speaking all the inertias I have seen come with a tag line (which normally breaks :blink: )

[Wilf dLampy]

Retail distribution companies are only ever transporting the same thing, e.g. pallets or trollies, that is they are designed for a purpose. ....... The trucks are packed according to the order stuff is required in the morning and when it becomes available during the load out, not by sorting it into the best loads from the perspective of lifting things.

Perhaps this is one area that could be changed. I know when I pack trucks, as you mention, it's always "What order do I need this in" and "how do I get these boxes to fit in that truck" with little regard for "should I/we be lifting this under the letter of the law". Maybe taking a lead from the transport industry at large and developing on the meatrack/dolly ideas used elsewhere in our own industry might be a step forward.

Oh, and personally I really like using inertia steels as a secondary where suitable as they are so easy to rig and derig.

Not sure about that. Firstly, it is another point, it takes just as long to pull up as a chain. The last time I used inertias they were 1T SWL and weighed 35kg, so the last 15m of the pull was about 39kg straight lift, and not fun. If the point is a bridle, don't you have to bridle the inertia as well?

Whether or not to use a bridle is entirely dependent on the needs of that particular point. The inertia is used as an independent secondary suspension. Yes, there are times when this means putting a (seperate) bridle on it, but it's still easier and safer than a traditional steel drop.

I am sure I have misunderstood this, but if you tie your rope onto the inertia, how do you pull up the next point? If you had 20 points to pull up (and 20 inertias) do you take 20 ropes up?

You asses the task at hand and derive a suitable method. It may be easier to leave the inertia connected to a grounded truss and (evenly) pull it up extending as you go (obviously on the larger inertias this is not suitable). It may be easier to tie a lightweight line to the inertia, send it up and then the ground crew pull it out and then attach the line to the next inertia they send up. It may even be possible to rig the inertias from a MEWP before the stage/auditorium becomes crowded with stuff (on the out MEWP access isn't as much of a problem as they can always be lowered in like a motor chain). My point was there are several easy ways to do it, and depending on the task involved one should easily be found that makes the process of putting in secondaries quick and simple.