# A question about truss



## tenor_singer (Feb 11, 2005)

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.


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## jonhirsh (Feb 11, 2005)

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
[email protected]


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## avkid (Feb 11, 2005)

*truss*

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


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## wolf825 (Feb 11, 2005)

tenor_singer said:


> 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.
> 
> ...



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


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## jwl868 (Feb 11, 2005)

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


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## tenor_singer (Feb 11, 2005)

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.


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## cutlunch (Feb 11, 2005)

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.


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## Peter (Feb 11, 2005)

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.


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## SuperCow (Feb 11, 2005)

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.


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## Les (Feb 12, 2005)

..


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## len (Feb 12, 2005)

Some other alternatives:

1. donations from a rental house. Maybe you'll get lucky.

2. Used on ebay. 

3. Get on mailing lists for auction houses. Find a club that's going out of business and get lucky. Even if you can buy stuff you don't need, you can turn it around and sell/trade it for stuff you do need.

4. Solicit donations of anything. Get it on ebay. Raise money that way.

5. Fundraising. In richer communities.


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## ship (Feb 13, 2005)

Kudo's to your intent on providing the best education you can. With patience it will all come. Perhaps with a bit of fund raising and ears open for constantly getting better gear. As you said, you have already upgraded a lot of the stuff. With time...

Welding is something useful to learn while in school. Often the students will learn it in a good college theater program, but banking on the usefulness for them to learn it on the farm in general, perhaps instead of doing something so ambitious as truss, you can start doing things that don’t require as tight of tolerances and normal welding skills. Also if you were to base your program off the AWS standards for certification, your students than with the practice you provide go on to get their certification. Perhaps contacting them might have some results in starting a program for this at your school or if in combination with a area business for their training also. At least than you would probably be able to get course materials for instructing in welding.

On truss, I forget if it was Lighting Dimensions a few years back, TCI or PLSN, but there has been some good articles no doubt in all about how truss is designed, what it’s constructed from and why, than above AWS welders, an extra certification I remember being necessary for those doing the welding. This in addition to as Wolf says, the X-Rays of the welds etc. Making your own truss for anything other than demonstration purposes to show weight distribution would be a very bad idea. What seems simple enough, even if you do overkill it will not be safe. Just because it's thicker material does not mean it will even hold as much weight as something that's specificially engineered for the application. Much less it's not just a question of getting parts to hang from that are sufficient to dead hang the weight, it's more a question of un-balanced and live dynamic loadings that parminant install materials won't be designed to hold up against. Much less no repuitable rigging company will hang anything home made - way too much liability in this for anyone involved with it.

Instead how about using the scrap steel you have access to for making items in the set? This would also save lots of money on lumber costs you could use elsewhere. Many schools use steel for anything from flats to even bridges across multi-level platforms. Given the staff must supervise the weld, have a certified welder probably doing the more dangerous welds etc. Still if a question of welding some 1" box tubing into a hard flat wall, students than could find useful ways to both learn to weld and have that welding become a part of the set. Used in the right placement, a 1" x 16ga piece of box tubing is as strong as a 2x4.

For the grid, 1.1/2" ID. Sch. 40 black water pipe (what most call 2" pipe) if not batten pipe is the standard be it fly system or dead hung grid. I have seen these welded in some places but again this should only at very least be done by a certified welder. The proper clamps and splices won’t be cheap but are necessary otherwise.

Part of teaching your students is not just how to make do with what you have or can make out of nothing, but what extent it is safe to do so. Truss not being one of those things. Now a staircase on the other hand....


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## Les (Feb 13, 2005)

Good advice Ship.

I would scratch the truss idea. Instead, wait and see if you can get something professional, yet practiacl to your needs.


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## ship (Feb 13, 2005)

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## SuperCow (Feb 13, 2005)

On a side note, who is this Sapsis Rigging I always hear about? I know Ship and some others have mentioned them in this sort of area. One would assume, by virtue of their name, that tey are a rigging company, but there must be more to them than that, based on how often I read their name here and on the Light Network.


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## Radman (Feb 14, 2005)

I am surprised you get funding. We are on our own. Luckily, we have been doing very well since our new advisor came on board. We are getting all new curtains and tracks, an ETC Express 24/48, and possibly some sound stuff, all from the profits we make on our shows! The only money we get from the school is when we want the district electrician to do something. Then we don't pay. This is actually how we are getting new dimming/distro! We're on the 10 yr plan for funding that little project!


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## tenor_singer (Feb 14, 2005)

Radman said:


> I am surprised you get funding. We are on our own. Luckily, we have been doing very well since our new advisor came on board. We are getting all new curtains and tracks, an ETC Express 24/48, and possibly some sound stuff, all from the profits we make on our shows! The only money we get from the school is when we want the district electrician to do something. Then we don't pay. This is actually how we are getting new dimming/distro! We're on the 10 yr plan for funding that little project!



We don't get funding either, which really chaffes because we see the community outpouring for other extra-curricular activities (I am trying to be PC about this), but not for drama, even though...

a. Our finished product is way better than the others.
b. We involve more students than any others.
c. We actually have had individuals make it.

I think that one of the problems we are having is that administration recognizes that a lot of TIME is put it, but there is an attitude that it really wasn't hard work. Our superintendent can't be bothered to come see our show. In fact he was heard by some parents in my boosters group who are also involved with the other extra-curricular activities (he used to be an athletic director... 2 + 2 = )... to say:

"Why does (my last name said rather pugnaciously) need two hours to set his floor lighting and sound system in the house! He is cutting into the basketball practices." (We opened that night at 7 PM and had to put our light stands on the floor and hang and aim our house lights and run our microphones...etc.).

I have learned to be very fast and constantly hunt for new, quicker ways to set up tech... hence the question about truss.

Good luck with your 10 year plan  .

Tenor


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## jwl868 (Feb 14, 2005)

ship

Does the theater industry really call 2-inch outside diameter pipe "2 inch pipe"? 

In the piping industry, 1.5-inch inside diameter schedule 40 steel pipe (1.6-inch inside diameter in reality) has an outside diameter of 1.9 inches, is called "1.5 inch" pipe. What I call "2 inch" pipe (schedule 40 steel pipe) has an inside diameter of 2.067 inches and an outside diameter of 2.375 inches. 


Joe


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## Radman (Feb 14, 2005)

tenor_singer said:


> ..."Why does (my last name said rather pugnaciously) need two hours to set his floor lighting and sound system in the house!...



Why? Because you give us no funding for decent equiptment that would take less time to setup!


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## ship (Feb 15, 2005)

jwl868 said:


> ship
> 
> Does the theater industry really call 2-inch outside diameter pipe "2 inch pipe"?
> 
> ...



I agree, however it all depends who you are talking to and to what degree they are trained or understand. 

I do not call Sch. 40 pipe other than by it's (nominal) ID. but I do find that many tech people in general - especially if their jobs are less technical detail orientated with nuts and bolts type of specific classifications, do call it by it's appairent nominal OD as if it were lumber.

My citing that many call it by it's supposed OD " is in recognizing this mistake in general and clarifying it to be incorrect. Short of verifying those you are discussing pipe with are on the same page as you, very often it will make for a lot of confusion.

This especially where structural Aluminum pipe such as used on truss is measured by OD is also talked about in the same discussion. 

My intent in speaking of water pipe is never to assume that those even that I work with know the difference right off hand unless I know for sure we are on the same page. 

I always make sure instead we are discussing the same item in recognizing the confusion and citing for clarification what other's call it. Otherwise in discussing pipe, I have had people come back with 1.1/4 pipe from a store when I asked for 1.1/2 in not understanding.


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## jwl868 (Feb 16, 2005)

Thanks ship. I work as a volunteer, for two shows a year. Because I have the time and the organizational skills, I coordinate the other volunteers and stage details, a de facto stage manager. Technical theater is not full time for me, and I am constantly on a learning curve (and thus my participation at this site). I try to sound like I know what I'm doing, but at a minimum, I need to be able to communicate with the technical staff (usually lighting and sound, and others who actually know what they are doing) at the venues that we rent.

Joe


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## ship (Feb 17, 2005)

Ah' than you will want to keep that difference between what we call pipe and what others that think it's lumber in mind. Believe me, even our shop manager used to call it 2" steel, or probably still does. This as opposed to calling our 1/8" thick wall structural almuminum pipe also stocked Sch. 40, 2" pipe. There really is a aluminum Sch. 40 pipe, but it is not the same as used on truss or in stock in being similar.

Than there is the experts in the plumbing aisle at Home Depot and other home centers. Ask for 1.1/2" Schedule 40 pipe, as opposed to Sch. 80 or Sch. 120 they would have no idea about, and you get PVC plumbing pipe. "I had always thought Sch. 40 stood for PVC." This might be the extent of their training in a much similar way to the general stage hand. And this is a direct quote from one of them.

Much less in sending a runner out to buy say some flanges, both the stage hand and "expert" sales person often get very confused without covering your bases with dummying down what you specify. The sales person in thinking PVC, and the stage hand in thinking it's either 1.1/4 pipe you specify given their understanding of what nominal is, or in getting confused 2" Sch.40 pipe after you say about 1.7/8" OD, pipe than with the explination over the phone and thinking you still meant nominal ID. Sending runners (those least valuable for the install) is rough.

In other words, in addition to saying 1.1/2" Nominal ID (Inside Diamater) Schedule 40 black water pipe (as opposed to galvanized or some form of RMT electrical pipe); you do also need to verify that those you are talking to know you mean ID and plumbing - water going thru pipe, and not OD (Outside Diamater) such as used on structural steel or aluminum pipe such as might be a post to hold up a house which uses the OD and a wall thickness as opposed to the Sch.40 to specify that thickness. Granted the Sch. 40 as opposed to the thicker Sch.80 and Sch.120 would to us be a thing that says plumbing pipe, it still goes over the head of those buying a 2x4 and wondering why it's not 2"x4" much less if they know this nominal dimension, know that plumbing pipes need for flow reasons that ID.

By the way, good point you brought up for others to learn from. You were very correct in citing the question of why I specified it how I do or why. I would hope all reading these forums thus know the difference between plumbing and structural pipe now.


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## ship (Feb 17, 2005)

Radman said:


> tenor_singer said:
> 
> 
> > ..."Why does (my last name said rather pugnaciously) need two hours to set his floor lighting and sound system in the house!...
> ...



Or because there was no or less funding, there was shall we say a learning curve, much less the gear coming to the event in being less organized in having people working with it for a living making it easy both to simply un-roll much less know plug A should go to connector A in being prepped for speedy install instead of figuring it out as you go. This or it just takes longer to de-funk in making useful the gear. This in addition to well made gear similar to the 1/4" speaker cable to Edison adaptor solution question, about what some might use in being hack and figure it out as you go, verses others that might come to the show with the gear all prepped to the point that the stage hands just need to match up one color of plug to the next as they pull it out of the box and it's done.

Doubling the set up time dependant upon both the skilled labor and the shall we say technique of the company coming in might at times be of advantage. Many factors here involving the production company coming in and the crew on site. Donuts also help in general. If it's a rainy day, and the crew had to go outside to un-load it will also take longer amongst many factors.

This plus if a good union or pro crew as it were, and a bad production company it will take extra time for those providing the gear to de-funk their crap. Or on the other hand, if a expert production company but amature crew it might take a little longer but not as much. All on the amature staus, perhaps trippling the time expectations might be reason for plesent surprises rather than the former.

Plan for the worst, hope for the best. Much less that the designers and various production managers don't change their minds too much artistically at the last minute. Crew's love this. Much less that the design was based upon another location and won't really fit here. Crews love that also.


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## NeroCaesar (Oct 1, 2014)

Hello,

I made the mistake of telling our contractors that for our grid we wanted 1.5" sch 40 pipe with out any other details, so when I came in the next day I found he hung it with Galvanized steel 1.5" sch 40 pipe. So I have been trying to search every where I can to find the specs with no luck, besides not being black and unable to handle ~20x more psi what are the disadvantages to Galvanized pipe for making a grid to hang lights on in a theatre.

Thanks for your time.


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## MikeJ (Oct 1, 2014)

jwl868 said:


> ship
> 
> Does the theater industry really call 2-inch outside diameter pipe "2 inch pipe"?
> 
> ...


This might be regional, but generally most people I have ever run into, call it by what it is. 1 1/2" black pipe, or schedule 40. And black pipe is generally for gas, not water.

People who refer to it as other sizes, either don't care, don't know any better, or like receiving the wrong size pipe.

Although I find it okay, for people to refer to it as 2" OD, sometimes handy if using other non-pipe hardware that needs to match up.
Example: some clamps will say size range, 1"-2" It can get a little ambiguous if you don't specify OD.


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