be that as it may, i've been commissioned for this project so i kinda have to do it. i have no doubts about the structure's ability to handle the weight of the speakers (there are engineers at the church). its not exactly a large church so calling in expert advice just isn't really in the budget. so again, any feedback on methods of doing this would be most helpful. i'll try to get pictures of the space for you, i just don't have any right now. its an A-frame ceiling with cross beams, one of which I was thinking about hanging the speakers from.
flying hardware
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No, you don't have to do it. You say there isn't money expert advice but will there be money for expert lawyers when something goes wrong? You betcha.
DuckJordan
Touring IATSE Member
Then turn it down you don't have the knowledge to do it right. Just as a contractor may not know how to build a barn he won't or at least shouldn't attempt to bs his way through it.
To expand upon my post, You brushed off some very important questions. Such as:
1. Have you had a structural Engineer in to see if where you want to hang them will hold the additional weight?
Without a minimum of someone who is willing to sign off on the project proffesionallly (Meaning they will take some liability when or if the points rip out) this project has hit a wall. Keep em on the ground. If you don't have the resources to do it correctly, then don't do it.
RIGGING IS NOT A PLACE TO SKIMP IN HARDWARE, EXPERTISE, OR FUNDING! If they really need to be hung they will get the budget to do it correctly, if not just don't do it. Another thing that comes up how are you going to get signal to the speakers when they are hung? are you going to run conduit to them? Are you going to use the correct type of cable for the job? What about processing to allow the room to be fully functional and not just be a giant echo hall that is worse with the speakers in the air?
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To expand upon my post, You brushed off some very important questions. Such as:
1. Have you had a structural Engineer in to see if where you want to hang them will hold the additional weight?
Without a minimum of someone who is willing to sign off on the project proffesionallly (Meaning they will take some liability when or if the points rip out) this project has hit a wall. Keep em on the ground. If you don't have the resources to do it correctly, then don't do it.
RIGGING IS NOT A PLACE TO SKIMP IN HARDWARE, EXPERTISE, OR FUNDING! If they really need to be hung they will get the budget to do it correctly, if not just don't do it. Another thing that comes up how are you going to get signal to the speakers when they are hung? are you going to run conduit to them? Are you going to use the correct type of cable for the job? What about processing to allow the room to be fully functional and not just be a giant echo hall that is worse with the speakers in the air?
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MPowers
Well-Known Member
OK!! End of the line. Now you are asking a question that we can not answer in good conscience. We do not know the structure or composition of your "ceiling" we don't know if there are beams or joists or.......! To give you good advice on this we need to be there or at very least have engineering drawings of the space, structure and load information.
I know you have said your speakers are only about 50 lbs, but if one falls, it can still be a major incident. We can give advice on Eye bolts, chain, turnbuckles, shackles etc, as those are all known elements.
You are at the point where you need some professional advice.
techieman33
Well-Known Member
Agreed, the expense of a rigger is nothing compared to the cost of losing a life.
Some of this might sound a bit harsh, but the general point needs to be reinforced.
I've noted this example up before but it seems rather apropos here. I had a project where early in the design process I talked with the original Structural Engineer for the building and went over the general concepts for flying the speakers. They said it should not be any problem as all of the beams had been designed for the worst case loads and our loads were very small compared to the structural loads involved. So we proceeded on that basis and had them review the final design at which point they noted that we happened to have picked the two beams that actually had the worst case loads and that could take no additional load. We worked out a solution, albeit an expensive one, but the point is that what even a qualified Structural Engineer initially thought would be no problem turned out to indeed be a problem once it was examined in greater detail.
I also remember standing in a church with someone saying they were sure that the wood beams would handle the speakers. However, it turned out that they were only assuming that because one of the other beams had a big heavy cross hanging from it. No one had verified if that one beam had been designed specifically for the extra load or if all the beams carried the same structural loads. With exposed beam structures it is common to make all of the beams look the same even if they are not really the same or carry very different loads, but because what they saw looked identical to them they assumed that everything related to it was identical when that is very likely not true.
As already noted, you don't "have" to do it. If this is a 'commission' for which you are being paid and you don't have the expertise yourself then you need to subcontract that expertise out of your fees and that should have been included in your bid or quote. If you didn't then it may turn out to be what would many would call an expensive learning experience and you would be far from the first to have that experience.
What is the basis for your assessment? What kind of Engineers and what studies or analyses were performed? What liability are they taking, in fact what liability are you taking and how are you protecting yourself and the church?
I've noted this example up before but it seems rather apropos here. I had a project where early in the design process I talked with the original Structural Engineer for the building and went over the general concepts for flying the speakers. They said it should not be any problem as all of the beams had been designed for the worst case loads and our loads were very small compared to the structural loads involved. So we proceeded on that basis and had them review the final design at which point they noted that we happened to have picked the two beams that actually had the worst case loads and that could take no additional load. We worked out a solution, albeit an expensive one, but the point is that what even a qualified Structural Engineer initially thought would be no problem turned out to indeed be a problem once it was examined in greater detail.
I also remember standing in a church with someone saying they were sure that the wood beams would handle the speakers. However, it turned out that they were only assuming that because one of the other beams had a big heavy cross hanging from it. No one had verified if that one beam had been designed specifically for the extra load or if all the beams carried the same structural loads. With exposed beam structures it is common to make all of the beams look the same even if they are not really the same or carry very different loads, but because what they saw looked identical to them they assumed that everything related to it was identical when that is very likely not true.
Then neither is flying the speakers. This seems a simple point, just because someone wants something does not mean it is viable or that they are entitled to it, if someone can't afford something then they can't afford it and don't get it. You and/or the church need to either figure out how to get a qualified rigger and Structural Engineer involved or you should to pursue other options for mounting the speakers.
well this project has officially become a necessity. by order of the fire marshal (the speakers are crowding the stage and thereby crowding an exit). I was considering (and by considering i mean intended on doing so) tabling this project until the budget came through but that's no longer an option. and there are literally all sorts of engineers in the church, from structural to computer engineers. but at this point, its beside the point since it has to be done. i'm still working on getting pics since i don't have a camera except on my phone and that's exceptionally crappy. and yeah, maseav, that did sound a bit harsh but considering the kind of experience i've seen you refer to in your posts i understand its reasoning. so, let me ask this: when getting an analysis done how much does it cost? and does anyone know of a company in the seattle area that does them?
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Again, hiring a professional vs paying a multi-million dollar law suit.... let's think about that.
Give my buddy Rick from TR professional a call. I'm sending you his personal contact info via P.M. He's an old road warrior audio guy. Used to be the pro-audio sales guy at Mills music, they closed that division and he started his own company about 4 or 5 years. He hung a big subwoofer for me a few years ago and is a great guy for these sorts of projects. My guess is as long as the access isn't too hard he would do it for $300-$500... and it's his responsibility if it comes crashing down. That's cheap insurance.
Give my buddy Rick from TR professional a call. I'm sending you his personal contact info via P.M. He's an old road warrior audio guy. Used to be the pro-audio sales guy at Mills music, they closed that division and he started his own company about 4 or 5 years. He hung a big subwoofer for me a few years ago and is a great guy for these sorts of projects. My guess is as long as the access isn't too hard he would do it for $300-$500... and it's his responsibility if it comes crashing down. That's cheap insurance.
BillESC
Well-Known Member
Rich or Steve at PNTA should be able to supply you with all of the materials and expertise required for this installation. Yes, it will cost a few more dollars than a DIYS but you'll be able to sleep at nights.
Or use Gafftaper's guy. You simply don't carry enough insurance to do it your self.
Or use Gafftaper's guy. You simply don't carry enough insurance to do it your self.
that was my plan but i'm wondering if should be done through more official channels to curb the liability issues.
If you've got some structurally savvy people, you'll be fine. Hanging a couple of Mackie loudspeakers isn't the kind of thing you need an engineer for.
You should have someone with some knowledge of carpentry, but a couple 50lbs speakers aren't the sort of thing that will collapse a roof, though they may fall if someone doesn't tighten a bolt down all the way.
There's no need to use a sword when a butter-knife will do. You just have to be able to recognize the difference between a stainless steel butter-knife and a flimsy piece of plastic cutlery.
You should have someone with some knowledge of carpentry, but a couple 50lbs speakers aren't the sort of thing that will collapse a roof, though they may fall if someone doesn't tighten a bolt down all the way.
There's no need to use a sword when a butter-knife will do. You just have to be able to recognize the difference between a stainless steel butter-knife and a flimsy piece of plastic cutlery.
well that's just annoying because the worship ministry director (who i'm obviously working very closely with) owns his own private contractor business.
MPowers
Well-Known Member
Problem solved! Just get HIM to sign off on whatever your beam attachment method is and you'll be fine. We've established that you can hang the speakers safely, the issue was with whether or not the roof would take the additional load, (High probability considering the very minimal load) and the method of attachment. The method of attachment was the break point and that is what you need to get approved.
To me the insurance is the issue. We hung a big JBL sub in my black box and I called in Ric to do it. I was certainly capable of rigging the speaker. It was quite easy, I could have done it myself with the school's genie lift in a half hour. But here's the problem, I no longer work at that facility. I have no idea how that sub is being maintained or if the rigging is being abused or neglected. What happens if 5 years from now, long after I've left the facility, that speaker falls and kills someone? Who are they going to sue? Me. I wanted nothing to do with that kind of liability. I hung stuff all the time on a show by show basis. But there's no way I was taking the liability for a permanent install of something I'm not going to be around to care for. I wanted Ric's butt on the line, not mine.
"Sign off", "approved", etc. imply their serving in a professional role and assuming professional liability. And if they are not working in a professional capacity, under contract, etc. then they may not be able to legally render such opinions, their Professional Liability insurer may not cover them and they may even potentially be putting their Professional License at risk. When you think about it, "volunteer" and "professional" are essentially mutually exclusive, one can be a volunteer or a professional but not both simultaneously. Thus a licensed professional may not be able to, or want to, act in a professional capacity without it being approached as their being contracted to provide professional services.
A simple example is that when I renew my Professional Liability insurance the form I have to fill out and sign includes questions such as whether I provide services without a Contract, whether I provide any 'pro bono' work and so on. The answers to those questions can affect my insurance rates or even whether coverage is offered and we can be talking hundreds if not thousands of dollars a year. And that is is just addressing professional consulting services and not even getting into the licensed Engineering or Contracting services aspect.
There is also the aspect that if the church receives professional services of some value without paying for them then they may be seen as receiving a donation of the equivalent fair market value. The church could hire a member in a professional capacity and that person then voluntarily increase their tithing, that resolves some issues but does then represent income for the professional.
So you may find someone willing to volunteer a professional opinion but it can certainly not be assumed.
As far as a couple of 50lbs. speakers collapsing the building structure, maybe not, but what about a 400lbs. to 500lbs. dynamic load during installation or should the mounting fail? And what about a 50lbs. load falling? What about potential seismic considerations and requirements?
This leads back to a question that has gone unanswered which is would the G30 chain be sufficient for the fail safe line? since the force exerted by a falling object is exponential to its weight i'm slightly concerned about this. according to an online calculator i found (so i'm not exactly sure about the reliability of this) the force exerted by a falling mass of 50lbs from a height of 15' is approximately 3200 pounds. however this would be falling all to way to the ground. falling to the end of the fail safe line as i would thread it would only be about 714 lbs. (falling only about a foot). now i've already confirmed the worship director's willingness to sign off on this so it would be in his best interest to make sure the highest probable fail points (the connections to the ceiling) are secure.
we are taking into consideration the possibility of an earthquake and the requirements of this. which, for me, is kinda amusing being a California native. a major earthquake in WA is the equivalent of a foot massage.
the annoying bit isn't that the problem is solved. its that it wasn't a problem to begin with. the fact that his OK is sufficient just means that i was already doing what needed to be done and don't need to incur extra costs by going with an outside structural engineer which seemed to be the prevailing sentiment in the posts previous to this. thanks for making me feel like a blithering idiot though, really appreciate that.
MPowers
Well-Known Member
The reason I mentioned using the resources you have, vs-a-vis the professional congregation members, is that we work with a number of churches in the area, ranging from one that has 8,000 + members and just built an $18 mil facility, to some with 500 members that have been built entirely by pro-bono in-kind architecture and engineering. They all have taken advantage to one degree or another of the professional abilities of their members. How they deal with the legal aspects of responsibility, liability, bid bonds, performance bonds, taxes and etc. I do not know, except that they do. For example, last year we installed a motorized clew winch in a church gym converted to a performance/worship space. Our installation involved adding structural steel to the roof to support point loads between the roof trusses. From those points we installed loft blocks, a head block and the winch, to hang a small 20' circular truss that supports lighting equipment two projectors and some sound gear, total of approximately 2300 lbs. plus the weight of the additional steel and rigging for another1500 lbs. Not a very large load or installation, but more than enough to hurt if it fell on someone. One of the congregation was a structural engineer and he did the official structural analysis and release for the project to approve both our structural design and the certification that the existing structure would support the additional loading. His firm and his signature was on all of the official project construction documents. We were told that his contribution saved about $8K from what it would have cost for us to supply the engineering study and various releases.
We experience the same in-kind of engineering in a majority of our church related projects.
We experience the same in-kind of engineering in a majority of our church related projects.
MPowers
Well-Known Member
Couple of things here.
First, a properly installed "fail safe" line (not the same as a lighting safety with lots of slack to allow focus movement) allows no movement or only a slight degree of movement before absorbing the weight of the object, thus reducing shock load to as close to zero as possible.
Second, If you are hanging the 52 pound speakers by the standard method of 2 independent chains (or cables) one each to the standard two top rigging points in most speakers and possibly a third chain to the center bottom back to adjust tilt, you have all the safety's you need built in to the system. Each individual chain or cable, even if only 3/16" or 1/8" respectively can handle 10 times the load by them-self, they are each other's safety. Multiple point rigging introduces redundancy in the design and that is just what a safety is, redundancy. Multiple point rigging is actually superior to single point rigging with a safety. In multi-point rigging, each suspension connection is under tension at all times. This means if any one of them should fail there is no shock load, only dynamic loading during the initial swing and pendulum action should one of the cables/chains fail.
Unless you are hanging by a single point allowing the speakers to twist and spin on the connection, you do not need any additional "fail safe line", the system itself provides more than sufficient redundancy to cover any contingency.
And, to answer your original question, if you feel the need add an additional safety, either 3/16 G30 proof coil chain or 1/8" GAC (either one properly installed) would be more than sufficient to do the job. Properly installed in this instance means all connections, crimps, clips thimbles etc done correctly and all slack removed from the line.
Last and not least, If the worship director is not a licensed engineer, his signing off does not release you of all responsibility or liability. In fact, even if he is, you or us in the case example I gave in another post, are not entirely off the hook. Should anything happen, the lawyers will try to show that "just following orders" is not an excuse for poor practice, ignorance of good practice, etc.
This is from NSPE, http://www.nspe.org/resources/pdfs/Licensure/Schinnerer_Advisory_on_Pro_Bono_Services.pdf.
I am not a lawyer, but based on related classes and seminars I have attended along with several other resources, pro-bono Engineering services for non-profits, including churches, is encouraged. However, there are apparently a few aspects that may want to be addressed:
- It is still providing professional services, just for no fee. The parties are acting in a professional role and not as a 'volunteer'.
- Services not clearly defined as being offered by the individual may put their employer or company at risk while services provided by an individual and not on behalf of an employer or company may not be covered under the employer's or company's liability coverage. Whether it is the individual or a company providing the services needs to be clear and understood by all. I have seen people lose their jobs for putting their employer at risk without their consent.
- Professional Liability policies may address pro-bono work differently. It may be treated as any other work, may affect the premiums, may relate to limited coverage or may even be excluded.
- It may still be advisable to have some form of Contract even if no fee is involved, if nothing else a Contract can help minimize confusion regarding what services were provided. And perhaps also a release of liability
- If it is viewed as the church soliciting 'pro-bono' services specifically to avoid paying for the services or of the professional offering pro-bono services to potentially take work from a competitor, gain an advantage, etc. then that gets into a very grey area of professional ethics.
- Understand that the language used can be critical. A professional may be hesitant to "approve", "accept", etc. but be more willing to "offer an opinion", identify "exceptions" and so on.
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