Moving Truss Over Audience

[cbarrett92]

Hi all,

I am asking for an opinion on how safe you think the following incident was. I was always taught that when a truss is moving (or line set for that matter) that no one is to be under it.

At my college our arena has truss flown in a circle all the way around the arena and about halfway into the audience to hang curtains and some moving lights. This truss surounds the court and is flown with CM Loadstar hoists. During a recent volleyball match they had hung new curtains in certain parts of the arena that reached the ground to make people sit closer to the action on the court and close off certain upper sections of the arena. When the all allocated seating in the stadium soon became full, in order to make more seating available, they simply raised the hoists and rose the truss and curtains up 15' or so to let people sit father up in the stadium.

My problem is that they did this while people were sitting directly under the truss, including me. The only reason I noticed was that I recognized the sound of the brake releasing and engaging from the motors.

Now would you consider this safe? There was no announcement made about the truss moving, etc. I know that technically the motors were way oversized for what they are currently holding, but I don't feel like moving truss over unsuspecting people's heads is a good idea. Am I just being too picky?

Thank you for your input.

Chris

 

[photoatdv]

Personally I would have no problem standing under a properly rigged truss while it moved. I do so quite often.

As for doing it over the audience... If it's designed/engineered for that sure (standards are higher in general for public vs staff).

 

[Toffee]

To be honest if the world stopped to move a truss and/or line set and people couldn't walk under it load in and load out would take FOREVER. as long as the operator is paying attention and knows the load it's fine. Over the audience as long as it is tested before hand and safe then who cares to be completely honest.

 

[BillConnerFASTC]

Personally I would have no problem standing under a properly rigged truss while it moved. I do so quite often.

As for doing it over the audience... If it's designed/engineered for that sure (standards are higher in general for public vs staff).

What standards are those? I actually know of none for public but OSHA does apply to employees.

 

[len]

As long as it's rigged correctly, it should be fine. And what difference does it make how many or for what reason people are under a truss? Other than 1 is an accident, 10 is a tragedy and 1,000,000 is a statistic.

 

[BillConnerFASTC]

Where in the built environment other than over a stage are loads hoisted over occupants' heads?

 

[gafftaper]

Let's face it our safety codes are screwed up and do not cover every situation. As long as none of those audience members work for the venue then OSHA doesn't apply. If the Life Safety Code or the building code doesn't cover it, which I doubt either does there is no legal code telling you not to do it.

On the other hand, is it good safe practice to do? No. Would a safety conscious rigger want to do this while the audience is present. Probably not.

But, in the end we come down to the boss getting a call from his box office saying we need to make room for more people to give us money and a technician saying, it's not a good idea but there's no legal code that says we can't. Guess who wins.

 

[BillConnerFASTC]

I basically agree with Gafftaper. I would never recommend moving something hung on chain motors over anybody - audience or staff - as I have received reports of failures. Were is a rigged piece - like on a line shaft that is engineered for the application - less bad but still not recommended. (I would not recommend leaving a truss hung just on chain motors static over heads and would insist on safeties designed to hold the load.)

 

[len]

Where in the built environment other than over a stage are loads hoisted over occupants' heads?

If I understand your question, stuff gets rigged over an audience all the time. The old Hearts Party did it every year. I think the 2006 ball at the Aragon had moving truss over the dance floor. Reed Rigging was in charge of it, IIRC

Any big stadium show where there's a B stage would likely have rigging over the crowd. I saw the Rolling Stones at the United Center and their rig extended nearly one end to the other, although I don't recall it moving.

And here's a recent one, with some movement over a stage.

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[photoatdv]

Personally I would have no problem standing under a properly rigged truss while it moved. I do so quite often.

As for doing it over the audience... If it's designed/engineered for that sure (standards are higher in general for public vs staff).

By standards I was generally referring to insurance and company policies. Though some local codes could come into play. I stand near/under a moving truss on CM motors multiple times a week and run one over people's heads typically at least once a week. All of these are designed so no single point of failure could drop the truss.

 

[ruinexplorer]

I don't remember how they had it rigged, but the truss in the old Studio 54 in Las Vegas would move while over the audience. They also had suspended performers over the audience. I only went there once before it closed.

 

[cmckeeman]

well we say that a dynamic load should have an 8:1 saftey factor so aslong as they are within that factor i think they are fine, to have moved it.

 

[FatherMurphy]

My preference would be to not move anything over the public's head - like most of us here, I know of stories of motors failing, and chains breaking, when one would not expect them to (usually traceable back to bad maintenance, not basic engineering), and there's probably more than one of us here who were in the building when such a problem happened. I'd just as soon everyone stayed out from under a moving truss.

Having said that, the basic design of the rig makes a big difference on how willing I might be to move the truss. A short stick of truss with two motors is a major problem if one motor fails, a longer stick of truss held up by several motors is less dangerous if one motor fails. Newly permanently installed equipment vs 20 year old touring gear on its twelfth owner also is a factor to consider.

It probably never crossed the truss operator's mind that moving the truss with an audience present might be a bad thing... that might be the most dangerous part of the entire story.

 

[egilson1]

Ron Bonner of PLASA did a study 2 years ago about this subject based on the EU practice of running a steel safety to dead hang trusses when using motors. To do so you end up with people on the truss to affix the safety. The rigging community there wanted to find out the actual number of motor failures to determine if it would be an acceptable practice to design the system with additional motors as redundancy instead of steel safetys. A summery of the results was

134 people responded to the questionnaires.

93 failures over 2,334 years of experience (based on the respondents to the survey)

Brake failures = 13
Clutch failures = 22
Chain failures = 19
Hook failures = 12
Other types of failures = 24
Reason for failure never identified = 6

Fatalities from falling rigging/equipment due to failure = 0

Injuries from falling rigging/equipment due to failure = 4

Number of multiple point rigs (>3) that fell as a result of failure = 0

Comments on the survey seemed to indicate that improper use or maintenance was the cause of most of the failures.

One last piece of data, the estimate of the number of Motors in use is hard to determine. It is estimated that between 2007 and 2011, 100,000 motors were placed on the market adding to the existing stock already being used.

 

[BillConnerFASTC]

The problem I see is that while this may be acceptable safe when done by truly qualified people with suitable equipment maintained in good condition, unqualified people see it and decide why not do that too. A high school teacher or community theatre person sees it at a professional concert and assumes there's noting to it. And I'm certainly not suggesting all high school theatre practitioners and community theatre volunteers are not qualified, but generally, lower budgets mean corners have to be cut.

Before 1992, the Life Safety Code did not permit pyro indoors. With a huge push and lobbying effort from the pyrotechnic industry - and I remember one major proponent represented the pyro manufacturer who supplied products for the Great White event at the Station in Rhode Island - arguing Disney and the Chicago Bulls and others used pyro indoors so it could be done safely. I agree that it can be done safely but not by anyone. So, what major players did with a lot of money and effort to get exceptions and variances to the codes and standards locally, now became a right that anyone could do if they filled out the right paperwork, and since it was so common, even the paperwork was not always done. And ten years after the change we have 100+ dead.

So, I'd say no, don't do overhead lifting over occupants without the extreme measures that require approval by the local officials and a clear paper trail of who is responsible for each aspect. Assigning responsibility in advance is the best method to assure no one cuts corners - not perfect or without lapses - but simply the best. Look at building codes and standards and you'll see that someone is responsible for everything.

Sorry to be such a hard butt on this but having argued against the code change to permit indoor pyro and lost, I redoubled my commitment to protecting all occupants of the built environment from unnecessary hazards on February 21, 2003.

 

[Focus]

As I recall, the worst problem in the Great White incident, was that most of the fire exits were chained closed. The same thing could have happened with other causes of fire as well. There were probably many regrettable decisions made that day, not just the use of pyro indoors.

Also in the case of moving the truss, we were not there, and people are basing their opinions on many assumptions. Without assuming, like others here, that the operator is an incompetent hack, as a general practice for professionals, there is nothing unsafe about it.

 

[ruinexplorer]

As I recall, the worst problem in the Great White incident, was that most of the fire exits were chained closed. The same thing could have happened with other causes of fire as well. There were probably many regrettable decisions made that day, not just the use of pyro indoors.

Also in the case of moving the truss, we were not there, and people are basing their opinions on many assumptions. Without assuming, like others here, that the operator is an incompetent hack, as a general practice for professionals, there is nothing unsafe about it.

The "worst problem" with the Great White incident was making assumptions that they were just fine doing things without regard for safety. This included making fire exits unavailable, allowing too great of a capacity in the building, using pyrotechnics that they were not permitted to use, and the list goes on. Would there have been a tragedy if they had not used pyro indoors and there were a different cause to the fire? Possibly. That doesn't really matter when you consider that it was negligence in using the pyro indoors, especially in this case. That is often the case when smaller productions want the same thing as the big guys (who have spent the money properly engineering the system) and feel that they can do it as well just because it has been done before.

You are right that we were not there with the moving truss. The OP did ask for speculation based on a situation observed. There is not a general assumption that the operator was a "hack". You are instead making the assumption that it is a generally accepted a safe practice to move truss over an audience. Certainly, there have been engineered systems that have the explicit purpose of moving above an occupied area. This may have been one of those systems. We can hope that the college did all of this on the up and up as well as having a documented training program for safe operation and regular maintenance. If they missed any of those points, that makes it an unsafe practice.

 

[BillConnerFASTC]

As I recall, the worst problem in the Great White incident, was that most of the fire exits were chained closed. The same thing could have happened with other causes of fire as well. There were probably many regrettable decisions made that day, not just the use of pyro indoors.

Also in the case of moving the truss, we were not there, and people are basing their opinions on many assumptions. Without assuming, like others here, that the operator is an incompetent hack, as a general practice for professionals, there is nothing unsafe about it.

I've spent many hours - days - in my position on the NFPA Assembly Occupancies Committee - with the lead investigators and the reports and so on. I've visited the site within days of the incident. I've studied the reports. Without the pyro, or with truly qualified persons in charge - in which case there would not have been pyro allowed - there would have been no deaths. So if the means of egress were not obstructed, more would have escaped and there might have been fewer deaths. If they had not put flammable foam on the ceiling, it might not have spread so fast and fewer deaths. As far as other possibilities of fire - there are not many I know of that start the fire in three separate places all at once like practically only pyro can.

As far as the truss, I offered that it could be done safely, but that it is also too easily allowed to be done unsafely, and therefore the standard of proof that it can be done safely at a specific event should be very high, with no opportunity to skirt by or sip any of the checks and balances.

 

[Focus]

Bill, you seem to be one of the most knowledgeable people on this forum. Thank you for your insight. I think everything you said above is true. You are right that people often see things done, and assume that they can do the same things without proper training. It is also unfortunate that the industry is often reactive, where something bad has to happen in order for changes to be made, and often the changes are not well thought out; just knee-jerk reactions.

It is good to know that there are people like you out there taking on these problems, before people get hurt.

Thanks

 

[BillConnerFASTC]

Thank you. You are very correct about regulation being reactive and not proactive by and large. Iroquois Theatre fire prompted big changes; Beverley Hills Supper Club; WTC; Station- had to wait till a large loss of life event to make changes.


The propensity to copy and one up in theatre is common; a part of what I call the backstage culture.