hello there.

Does anyone have a support detail for support of vertical PVC pipe? What are usually the criteria for supporting a verical PVC pipe say 20M high? typical connection to PVC pipe of support,,Pipe is say 8" S80 CPVC pipe...allowable load on support connection?

Your help is highly appreciated...

You are going to have to do a lot of hand calculation for this one. I suspect that, if your pipe is full of liquid, you will have to account for axial strains (that CAESAR II ignores) in your support design.

Other than that, I don't see why the methodology of BPVC Code Case N-392-3 would not apply. You will obviously have to either glue on lugs or trunnions to your riser in order to support the weight; friction just isn't going to hold it up.

If possible, can you "stair-step" your riser, where you put in a little offset at several different elevations to avoid the long vertical run? This will make the support design a whole lot easier (but may aggravate your process engineer and plant layout guy).

I would never use CAESAR II for plastic pipe. I would use pipe/fitting supplier's calculation rules. One good supplier who gives all this is AGRU in Austria. They have a solution for your problem also. It is called dog bone. Remember plastic is sensitive to temperature, it creeps and does other strange things.

Thanks all for the reply... I think I like the idea of "stair-step"..

CraigB am I right about my interpretation that the axial strain is the downward deflection due to weight and pressure of long vertical pipe? Thanks for your time..

Best Regards to all and Cheers,

[...and if your pipe is not "full of liquid" but instead e.g. is carrying something like compressed air, I believe some authorities/regulators would now require you to "support" such exposed piping (that might subject any folks in the vicinity to danger of exploding pvc shrapnel from same) inside a separate, fully enclosing larger metal pipeline.]

Hello all! Have anyone know a typical strength of a glue on a pvc pipe glued to a trunnion?...Or when I pass the local stress calc for the pipe and trunnion my glue is also ok, assuming it is as strong as the pvc...Is this the typical case...Your help is highly appreciated...Many thanks...

Cheers,

I would definitely not consider the glue to be equally strong as the pipe itself. Check thermoplastic piping or vessel codes for joint factors.

Thanks for the input...I am planning to glue the pvc pipe clamp to pvc pipe, instead of the trunnion...But I can't find a glue with a given allowable shear strength...Is there a typical value for the glue shear strenght or does anyone know a specific glue with given shear strength...Thanks in advance...


Cheers,

Borzki,

The pvc pipe needs to be reinforced at the support point. Supports would usually include saddles to spread the loads on horizontal piping. A point type load is not recommended for plastics or FRP pipe materials. The vertical support location on the pipe could be a socket cemented pvc coupling where the shoulder of the coupling would rest on the riser clamp. The solvent cement for pvc socket fittings would result in joint strength equal to or greater than the pipe itself. Consult the pvc pipe and fittings manufacturer for recommended solvent cement. Some include a primer coat with the recommended solvent cements.

Thanks Richard for that valuable input..For modelling PVC pipes what is the usual joint SIF, such as the socket coupling..Does manufacturers provide this kind of information, based from the results of their tests?...Or an SIF of say 2.3 in the in-plane and out-plane would suffice for analysis purposes?...Many thanks to all....

Cheers,