A question about truss

[tenor_singer]

I am fortunate enough to work at a high school that still has a vocational agriculture program left (the State of Ohio tends to cut these programs).

Long story ... well... long (sorry)...

I am moving into a new school next year. I would like to have some truss to hang my fixtures from. When I priced it up I was stunned. We are a very poor district, but we have a place willing to donate lengths of tubing.

My thought... our ag teacher is willing to partner up with me and my crew to teach them welding (I figured that would be a good skill to have... especially in our farm-based community). Our project is going to be welding and constructing our own truss work out of the donated pipe.

Any suggestions you have AND any codes, safety issues etc. you can think of and tell me would be greatly appreciated. We have probably thought of every angle, but I want to be sure so that everybody is safe.

Thanks!

Tenor.

[jonhirsh]

My first reaction is yah go for it saveing money is awsome. but if you think about the posible dangers involved you have to weigh what a life is worth when you hang a pice of trust that isnt safe and it falls on a audiance member and kills them how will you feel? Regulations aside it is a dangerous idea why do you need truss do you have a grid? if not why not build a grid out of 2 inch pipe first then work on the truss it all comes in stages dont rush it.

If you need any advice or help Call me or email

Jon Hirsh
Black Horse Productions
416 371 2216

[avkid]

try building lighting stands instead of truss,they are safer,and you do not have to deal with building codes!

[wolf825]

Originally Posted by tenor_singer

My thought... our ag teacher is willing to partner up with me and my crew to teach them welding (I figured that would be a good skill to have... especially in our farm-based community). Our project is going to be welding and constructing our own truss work out of the donated pipe.

Any suggestions you have AND any codes, safety issues etc. you can think of and tell me would be greatly appreciated. We have probably thought of every angle, but I want to be sure so that everybody is safe.

Thanks!

Tenor.

Um....

Um...truss in general is a designed and mathimatically formulated combination of proper materials, proper manufacture and dimension to ensure proper weight distribution and bearing ratings. SO...the first few things that come to mind with your proposal is that truss welding is very specialized (especially if you are doing aluminum welding--which is VERY difficult to learn to do properly as its way too easy to blow a hole thru it or make a poor joint) and a beginner won't begin to do very good welds until they have put several several dozen hours of actual welding time under their belts. It takes skill to weld and listen to the sound (for blow-thrus), to see the weld and beadings, and ensure proper connection. Also--last time I checked with Tomcat, their commercial truss has their welds inspected and checked with radioscans(x-rays) for quality of the weld..and their truss is RATED for weight. I guess the question comes down to this--Can you or your guys ensure your welds and rate the truss you make for weight and for overhead use, and guarentee or assume liability for your work should there be failure? Can you ensure the pipe you are using is of quality and proper thickness and structure? Anyone can weld and make whatever they want--but if you plan to put it over peoples heads, make sure the folks who weld are GOOD and do GOOD WELDS, and the material used is proper for the job. Also--truss is nice but has its distance limitations and point requirements for hanging, and mathimatical dimensions of the truss for weight bearing and distribution...

IMO, It is a lot safer to use proper schedule 40 pipe, and hang that with proper pipe hangers and rotolocks.. Not trying to discourage you..but just some things to consider. Good luck...

-w

[jwl868]

I can't add much else to what wolf825 posted.

A pre-fabricated truss would probably have been designed by a professional engineer such that the metal grade and dimensions and welds/bolting would all meet the design requirements. (I would even expect that an experienced structural builder and welder can do a proper job, but the paperwork/calculation behind the design may be absent.)

But you are constructing a permanent load-bearing structure for a school (public school?) and I would except that there are minimum standards set by the state. I'm shooting from the hip here, but I would think that the welding needs to be performed by (or at least under the direction of) an American Welding Society (AWS) certified welder. And the design will probably need to be prepared by a professional engineer.

There may be labor issues – is a union welder required? There's an even chance that you (but not the students) must do this in a workplace that conforms with OSHA.

It sounds like your project could be considered as a permanent modification to the school. You should go to the school board or administration about these sort of projects.

Joe

[tenor_singer]

I would love to just purchase the truss and be guaranteed safe. Maybe down the road, then.

I want to explain myself a bit so that wrong perceptions aren't created...

What I am sighing about and why I come up with these crazy questions you often times see me post (upgrading 30+ year old fresnels... etc... )... I look at the pictures posted on this site by people who consider their equipment junk and who complain about their 100+ channel light board and dimming capacity not being sexy enough or that their auditorium control booth looks a bit prehistoric, while simultaneously looking at my 16 channel NSI board with RD4600 satellite packs (only 4) that is set up on a folding table in the back of a GYM going... hmmmmmm. Their stuff would be a 500% improvement for our program. I really want my kids to have the best and unfortunately because the majority of our community live at the poverty level, our school... which has not gone back to the public since 1985 for levy money... is a bare boned, lean machine that could care less about drama or their equipment needs. Sound wise... we're doing ok. How can you teach the fine nuances of lighting design with only 27 fixturees that barely wash your area that you can't hang well because of a lack of a grid... per say?

Seven years ago all they had were coffee cans with ceramic fixtures pounded through 2" holes in one end with electrical tape holding them on and metal coat hangers jimmy-rigged to the sides as yolks that were plugged into a "light board" that was constructed like an "A" frame house out of paint stirring sticks with eight wall sockets wired in series to eight switches that themselves were run through a 15-A household rheostat switch. Their lamps were normal 150W spot bulbs. They had zero sound and the curtains were 75 years old and so dry rotted that they would not hold a stitch and would rain dry pieces of the material if we bumped them wrong.

I have advised others here about patience and I practice my preaching. We've come a long way, but frustration levels are climbing. My students have busted their butts. We now have new curtains (7 years old), a sound system with wireless microphones, 9 360Q's, 6 Aces, 6 6" fresnels and 8 PAR 56's. We have the lighting capacity that I mentioned earlier. However, I am worried, that we will never reach a level that a well funded school has and that my students, all of whom I want nothing but the best for and some of whom aspire to enter the technical theater field, will suffer because of it. Hell... I don't even have a theater degree myself... only mathematics and physics and I willingly admit to technically flying by the seat of my pants from time to time (staging is fine because of years of community theater experience).

I throw this out so that you all don't think that I am some nut trying to build things that will get my students hurt. Yes... I am trying to save a buck (our yearly budget is only $5,000.00 and that purchases capital equipment as well as funds our play and musical), but I am not trying to get people hospitalized. I saw a rig this weekend at the Cleveland Home and Garden Show and thought it would be cool to get something similar (if affordable) so my kids could see a different approach towards lighting a show. Then I did some price research and choked. That is when our ag teacher and I came up with this idea.

Maybe we are thinking too big for now. You must admit, though... it would be cool to show the kids what using that piece of equipment would be like. Oh well...

Thanks for the advice... long day... haven't been home to see the family yet... ciao...


Tenor.

[cutlunch]

Good on you Tenor for putting in the extra miles with your students. It actualy sounds like your students are getting better training under you then they would at some of these schools with everything. I believe that someone who has only worked with a small amount of equipment can easily move up to more. It is a lot harder for someone use to everything to go to small amounts of equipment.

JohnHirsh made a good point does it have to be trussing? If it is meant to be permanent, the two inch pipe idea is good. By having droppers coming down from the ceilling beams you should be able to support enough weight per metre length to have a safe bar.

It would be interesting to see how many schools actually use trussing instead of just the pipe. Also the suggestion of lighting stands being made is a good one, they always come in handy but will still give students welding skills.

[Peter]

Yes, it does sound like your students are getting a good education, and this is comming from a kid in a brand new facility, but one that has no one more experinced then I, so I have to make everything up and just learn from my own mistakes.

If it is any reassurance, we dont have any trusses, only a few pipes and those are stratigically placed to allow the least amount of flexability b/c of their location close to teaser curtains.

[SuperCow]

I woud go withe the towers. Truss is a complicated thing. IO suppose your Ag teacher would be capable enought to weld it together, if he is an experienced welder, but I would hesitate to let students put together that crucial.

Either way, I think you'll be better sever by just using the pipe as-is.

[Les]

This is what I say. Go somewhere and look at some truss. Go to websites and read up on the grade of material used for building truss. There are many different right ways to build a safe section of trussing. The material you are using will have an effect on the finished product. I am assuming you are probably using 1.5" ID Steel pipe. So what I would do, is research trussing made of that exact same material and copy the design. Alot of steel trussing uses only 1" Steel tubing, so if you copy that design, with thicker tubing and the same amount of braces located in the same orientation, you should be well off. Your trussing will probably be even stronger than the smaller stuff. Another thing to consider is the length of the truss. I would make the sections no longer than 10', maybe even shorter. This way, each section won't weigh a ton, and it will be easier to hang and install. On the ends of each truss I would 'box' it in with angle iron with tapped holes, 3 per face. This way the ends of your truss will be much much easier to connect. I would also think about how to hang the truss. There are several ways to fabricate brackets, some right and some wrong. I would fabricate hangars on each end of each truss, so every 10' will have 2 suspension points. I would hang the truss (assuming it's triangular) Apex Down. \/ . As far as hanging hardware goes, I imagine anything industrial that is designed to continuously support a large abount of weight would be acceptable. (something similar to All-Thread).I would definately go to a steel supplier and see what they have. Go up there and tell them what you are doing and how much weight you are holding up. ALWAYS give them a ridiculous over-estimate. You want this system to be 4-times as strong as you need it to be. Overkill is good. For structurally hanging this truss, I would out-source. See if it is possible to have a company come do it for you. Someone certified in construction dealing with I-Beams and the like. It would also be a good idea to have the trussing thuroughly inspected prior to hanging.(by a third party).
When it comes down to it, it is so much more complicated than it needs to be, but it will be well worth it.

Hope this helps! also, the cheapest trussing I have ever found is located at www.cheaplights.com. I bought myself 19.5' worth of 2" aluminum trussing (3x6.5' sections) and it only came up to $300.00. It seems to be an excellent product and it came with the conical couplers needed to connect each section.





[img][/img]