u-PVC & c-PVC

[zishan99]

What is the difference b/w u-PVC & c-PVC pipe? Can i use the c-PVC piping specs in u-PVC pipng for waste water service in a chemical plant?

Thanks and regards.
mechanical19k96@hotmail.com

 

[rconner]

While not claiming to be much of an expert in this field I'll take a shot at this, as for some reason you've not yet gotten any other responses -- I believe cpvc refers to "chlorinated" pvc, I think meaning along with whatever else that the basic polymerized plastic has one more chlorine atom and one less hydrogen than the basic polymer structure of basic rigid "pvc" (that I think is most commonly also referred to in some areas as upvc or "unplasticized" pvc) plastic. While still resulting in a material that exhibits a reduction in “minimum breaking strain in relation to time” (or stress regression) and a degradation in some long-term properties with the introduction of some amounts of cheapening fillers, I believe cpvc with a significantly greater percentage of chlorine is understandably a somewhat denser plastic material with generally some greater short and long-term tensile strengths, particularly at higher temperatures. I believe you would see this if e.g. you were to superimpose the stress regression curves of the document “Material and System Selection” at

http://www.us.piping.georgefischer.com/external/us_handbook/01.pdf.

on pg 1.28 for “cpvc” over the similar curves for “pvc” on pg 1.27 .
I suspect the cost of cpvc is also greater than pvc for the same schedule/thickness (I guess due to extra processing issues etc.), as appears is also illustrated on this same basic site where you can compare at least list prices at

http://www.us.piping.georgefischer.com/index.cfm?D4D043C82557B9318B12F44530E1CBD6.

I know some failure modes of both types of piping were discussed in a paper “Failure Analysis of PVC and CPVC Piping Materials”, by Michelle Knight of Noveon presented in NACE “Corrosion2003”, though CPVC is apparently alleged by some to be a “...stronger, more chemically resistant material..” (such as when offered up as a replacement for failing regular pvc ventilation piping such as in the article, “CPVC Piping System Prevents Corrosion” at

http://www.pfonline.com/articles/089804.html).

You might consider posting this in the “Plastics Engineering” forum if this information is insufficient.

 

[zishan99]

Thanks rconner (Civil/Environme).I need to know the design and detailing aspects of the use cpvc/upvc pipe.

Regards.
mechanical19k96@hotmail.com