UV protection for PVC
UV protection for PVC
(OP)
Hi, can any one help me with information on how to protect a pipe of PVC from the sun, here in summer we go up to 115°F, is there a paint that we can use of some kind? Or is there another pipe material that can take the heat, sun and handle corrosive material?
Thanks
Thanks





RE: UV protection for PVC
RE: UV protection for PVC
http://virtualpipeline.spaces.msn.com
"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain
RE: UV protection for PVC
Take a look in there under PVC and CPVC. Both require a water based latex paint for UV protection. CPVC will probably give you better overall service. The resistance guide at http://www.hipco.com/chemGuide.cfm is also useful.
jt
RE: UV protection for PVC
RE: UV protection for PVC
You may want to consider other materials with your high ambient temperature in the summer. 115 Deg outside means the surface of the pipe is likely much higher. PVC has a maximum service temp of 140 and loses much of its strength and pressure capability at that temp. CPVC will be better as it is rated to around 200 deg F.
Lastly, make sure you compensate for expansion and contraction in the PVC or CPVC line. With large temperature swings, it can be considerable compared with metal or FRP.
RE: UV protection for PVC
Go to any waste site in an industrial complex and it will be strewn with PVC as pressure pipe, electrical conduits and drainage.
On top of that the "green" credentials of a project have resulted in its ban in many countries.
RE: UV protection for PVC
True, PVC can be embrittled by prolonged direct sunlight exposure, but that's easily mitigated with coatings with or without insulation. In low stress applications it's used successfully with direct sun exposure lifetimes of 20-30+ years WITHOUT coatings, and without ill effects.
Yes, it's brittle at low temperatures and reduces in strength as it gets hotter, with an upper limit temperature around 60 C. It's also essentially immune to corrosion by media that are VERY troublesome for metallic materials of far higher procurement/installation cost, and it's very easy and cheap to install- something that cannot be said of FRP or lined metallic piping. And unlike HDPE, PP etc., it requires only the most basic equipment and pipefitter training to make sound joints.
PVC and CPVC are materials like any other: with strengths and weaknesses. Know these and you can design around them.
RE: UV protection for PVC
RE: UV protection for PVC
I agree with your sentiments. I was just passing on some information.
These days many engineers buy on price alone. I have been involved in many investigations and court cases when the cost of a failure (including the lawyers fees and consequential damages) far outweighs the savings.
Plastics pipe design is actually more difficult than for metallic produicts. The engineer has to know a lot more. The challenge is that many of the design guides, standards and codes lull youinto a false sense of assurance. The only requisite in many is to design for hoop stress and ignore shear, bending, torsion and other stresses. They ignore fatigue affects on thermoplastics and required derating. They ignore the strain rate change in properties and the affects of temperature.
Yes good old PVC is cheap. Certainly it is more prone to failure than other quality thermoplastics and metallic products. Yes it is misunderstood and misused by ignorant people who do not have the time or inclination to spend the time to learn more than what the salesman offers. It earns me a good living when these poor sods stuff up and get sued.