Set Design and Construction: PVC pipe support capability?

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PVC pipe support capability?

Printed From: Community Theater Green Room
Category: Producing Theater
Forum Name: Set Design and Construction
Forum Discription: Post your questions or suggestions about designing or building a set here.
URL: http://www.communitytheater.org/forum/forum_posts.asp?TID=4414
Printed Date: 11/23/24 at 6:58pm
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Topic: PVC pipe support capability?

Posted By: ChrisTopher
Subject: PVC pipe support capability?
Date Posted: 1/11/10 at 7:56pm

Hello
I am tech director in a small community theatre and have started using PVC pipe and coroplast to create flats, silhouettes and even furniture. We do many children's productions. I love the light weight of these pieces. Where can I find the load bearing properties of pvc pipe? Can I support a small platform using 4" PVC legs? Just how strong is this stuff? Thanks for reading and for any help you might give. I am new to this site and am devouring your collective knowledge already .Thanks
Chris

Replies:

Posted By: Spectrum
Date Posted: 1/12/10 at 1:48am

The structural strength of PVC pipe depends on the many variables of what type of PVC pipe you use and how you use it (i.e. schedule 40, schedule 80, small diameter, large diameter, short length, long span, glued joints, dry fit joints, etc.). A good place to start might be here:

http://www.harvel.com/pipepvc-sch40-80-dim.asp - http://www.harvel.com/pipepvc-sch40-80-dim.asp

You may even want to contact the manufacturer for specifics about a design you want to do with their product. My guess is if you used 4 inch diameter PVC as the legs (THICK WALL) and the height of the platform wasn't too tall, you would have no problem, but I'd also be concerned about it sliding on a hard, smooth surface. The sideways stress on long legs would be working on PLASTIC flanges, so unless you have diagonal support in your design, you may have trouble there. Good luck!

ADDENDUM to my original comments:

I heartily agree with the folks who have commented after me; using PVC to support a platform is NOT a good idea, and the only instance I was thinking of where it might work is using 4 inch schedule 80 (thick wall) pipe to raise a platform to a height of no more than 6 inches. Relatively short legs could support a platform (and the weight on it) very easily if done properly. (Per the PSI compression limit of 350 pounds, 6 legs X maximum weight per leg less than 300 pounds). Even then, I agree with the folks who have said there are far better alternatives.

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Growing old is mandatory. Growing up is optional.

Posted By: phialv
Date Posted: 1/13/10 at 6:53pm

Hi Chris,
I'd recommend NOT using PVC to carry the kind of weight you're thinking of. Even if it 'could' bear that weight, it's not rated for that purpose, so any guess about it would be just a guess. Also, any rating of load would not account for the possibility of a horizontal force that could shear or break the pipe. And that risk is probably considerable if the load is high off the ground and movement is taking place around it.
Phil

Posted By: Gaafa
Date Posted: 1/13/10 at 9:04pm

If your want is to go plastic? Something I have used to great effect is plastic milk crates, locked together to cover underneath a small rostra deck area plate. Also quite good for the inside support of rostra steps.

Structualy they will withstand any adverse movement & are light weight.

I would not have plastic pipe on my mind for any type of support & I agree with the other posters.

-------------
Joe
Western Gondawandaland
turn right @ Perth.
Hear the light & see the sound.
Toi Toi Toi Chookas {{"chook [chicken] it is"}
May you always play
to a full house}

Posted By: David McCall
Date Posted: 1/14/10 at 10:40am

The "milk crates" sold in retail stores in the US are really flimsy. The only good ones that I've seen have mostly been "stolen" from milk companies.

Using PVC pipe to support platforms with people on top is not something I would recommend in public. It might work, but "might" isn't good enough. You could try to reinforce it a little by putting wood inside of the pipe, but still?

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David M

Posted By: Mr. Lowell
Date Posted: 1/14/10 at 1:26pm

Personally, I would not use PVC as legs for supporting platforms. While it may support the vertical weight, I wouldn't trust it to support the side-to-side stress of actors or dancers without breaking. And platforms really need to have X-bracing to support this lateral stress...but I don't know how I could form strong diagonal joints with PVC pipe.

However I would definately use PVC for non-weight-bearing units such as tables, flats, "trees", and even small chairs.

I have also used cardboard carpet tubes for making any number of units such as railings and table legs. But I always use 2"x4" or 2"x2" lumber inside the carpet tubes for support. The advantage of cardboard tubes over PVC pipe is that the tubes are plentiful...and free! PVC can get expensive.

By the way, another alternative material that I have used is PLASTIC shipping pallets. (These are the heavy-duty PVC pallets made to ship 1 ton truck motors and such). A local company that grinds up wooden pallets to make mulch just happened to have a dozen plastic pallets lying around...and they gave them to me free! In this photo from "Return to the Forbidden Planet", you can see the bandstand was made out of plastic pallets. I wanted to use these perforated pallets so I could shoot 750 watt ParNel "up-lights" at the musicians from underneath, yet still support their weight.

http://www.lowell.to/posters/PLANET005.jpg - http://www.lowell.to/posters/PLANET005.jpg And in this photo taken from the catwalk you can see the stage-right trapdoor where the two guys are standing is also a plastic pallet. http://www.lowell.to/posters/PLANET023.jpg - http://www.lowell.to/posters/PLANET023.jpg This grill allowed for a Marilyn Monroe gag using a leaf blower underneath! http://www.lowell.to/posters/PLANET045.jpg - http://www.lowell.to/posters/PLANET045.jpg (Guys on crew used to fight over who got to run the blower!)

Good luck and have fun. -Dana

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Mr. Lowell,
Lighting/Set Designer & Tech Director,
for the Linda Sloan Theatre,
in the Davison Center for the Arts,
at Greensboro Day School

Posted By: Gaafa
Date Posted: 1/15/10 at 5:25pm

The old milk crate I refer to were used when milk was delivered in glass bottles.

There still is a fair amount knocking about, although they are now closely guarded by thier surigate owners these days.

http://milkcratebook.com/ - http://milkcratebook.com/

-------------
Joe
Western Gondawandaland
turn right @ Perth.
Hear the light & see the sound.
Toi Toi Toi Chookas {{"chook [chicken] it is"}
May you always play
to a full house}

Posted By: ChrisTopher
Date Posted: 2/01/10 at 10:12am

Thank you all for the advice and I will continue to use PVC pipe to support flats and various set pieces but find other means to support any significant weight. I found your informative insights useful and will try other cost effective means of construction. Any and all suggestions are terrific. I have scrounged coroplast from some local sign painters. I find that a restrictive budget, though annoying, spurs creativity.
Thanks again
Chris

Posted By: TimmyP1955
Date Posted: 3/07/10 at 7:57pm

Go to http://www.keesafety.com/us/products - Kee Klamp then scroll down to the Safety Components - Kee Klamp section and click the Online Catalog button (unfortunately one cannot link directly to that page - another junk Flash based sight no doubt).