I've heard over the years that PVC should never be exposed to ultraviolet radiation, or the pipe will crumble and disintegrate. Though upon researching the subject, it seems as though UV radiation only reduces the impact strength of the pipe. Is UV degradation is a real problem, or a half truth propagated by the internet.
According to an article by United States Plastic Corp. (Is PVC and CPVC pipe UV resistant?), and a technical bulletin released by JM Eagle. Only the pipe's impact resistance is reduced, while both tensile strength and modulus showed no reduction.
While I know that painting, or wrapping the pipe can eliminate any damage. I wonder if it's even worth the effort to do so, in most situations? Since the pipe maintains it's pressure capacity and stiffness, is protection required if the pipe is in an area where it's not subject to physical damage? Can UV radiation alone, cause a catastrophic failure of the pipe?
Best Answer
I work in an environment that has 384 54W T8 fluorescent lamps and one PVC pipe. The pipe was unwrapped and began failing (crumbling apart) in 9 years. It wouldn't have held up to a someone bumping into it for probably a year prior to that, either. Your conditions will probably be less extreme, but it's a good idea to wrap or paint your pipe.