Technical Blog

Welcome to John’s Blog. Answers to frequently asked questions are periodically posted here. The objective is to share information about PVC pipe with readers as well as with utilities, design engineers and pipe installers. The blog provides the latest information on PVC pipe design, installation, and application for water and wastewater infrastructure projects.

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John Houle: Senior Technical Consultant, PVC Pipe Industry

John Houle holds a Master’s Degree in Civil Engineering from the University of Missouri and an MBA from the University of Oregon. He has more than 25 years of experience in the plastic pipe industry in applications engineering, market development, forensic analysis, technical writing, and standards development.

UV Exposure/Sun Fading Has No Practical Effects On PVC Pipe Performance

Posted By John Houle on Mar 20, 2013

UV Exposure Has No Practical Effects on PVC Pipe Performance​The effect of sunlight on PVC pipe has been a misunderstood topic. Negative attacks by our competitors allege that exposure to sunlight causes PVC pipe’s properties to degrade so severely that the pipe becomes unsuitable for use. The attached technical brief rebuts this contention. Click here.

As with many subjects, there is a germ of truth to the allegation: it is true that UV radiation from sunlight can affect the outermost surface of PVC pipe. However, even after prolonged exposure, there is no practical effect on the pipe’s performance characteristics.

Two-Year UV Exposure Study

A two-year study has quantified the effects of sun fading on the properties of PVC pipe. The research found that exposure to UV radiation results in a change in the pipe’s surface color and a reduction in impact strength. Other properties such as tensile strength (pressure rating) and modulus of elasticity (pipe stiffness) are not adversely affected.

It is important to realize that the average impact strength after two years of exposure still remained above the level required at time of manufacture. There are no restrictions on cutting or tapping of UV-discolored PVC pipe. As well, sun faded pipe can still be installed with less care than is necessary for more vulnerable clay, concrete, or mortar-lined/epoxy-coated ductile iron alternatives.

The Bottom Line

On a practical basis, exposure to UV radiation has no performance-based effect on PVC pipe.