A question about truss

[jwl868]

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

 

[ship]

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.

 

[ship]

..."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!

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.

 

[NeroCaesar]

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.

 

[MikeJ]

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

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.