PVC Pipe and Outside Storage Length

[JayHatCOB]

As a rule of thumb, how long should our water department store uncovered and unprotected PVC pipe? All of the pipe is stored outside in our storage yard. The pipes range in size from 1"Ø to 10"Ø.

I've read so many different thoughts regarding UV degradation of the PVC pipe that I don't know what is an acceptable storage time frame.

 

[dicksewerrat]

Take a few samples of the unprotected pipe and a few samples of new pipe. Send to a lab to get Flex Modulus, Flex Strength and Tensile Strength. Then decide if you should be scapping all the unprotected pipe. If you know when the unprotected pipe was delivered that would also be good. I think a tarp would be a cheap way to keep the UIV degradation down. Also this way you can check what is being sold to you by comparing the manufacturer's data and test results.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[JayHatCOB]

dicksewerrat,

The pipe that is in the yard has been there for 5 to 7 years.

 

[rconner]

Don't know about "thoughts", nor if your pipe has enough "goodie" left to handle your service. What I have seen however is a some detailed summary of some tests run of outside exposure of pvc pipes at 12 different test sites in the USA and Canada to gauge deleterious effects of outdoor ultraviolet radiation on a total outdoor exposed population of 130 pvc pipes [Uni-Bell PVC Pipe Association (Uni-Bell 2003), “The Effects of Ultraviolet Radiation on PVC Pipe”, UNI-TR-5-03.] You may be able to locate this now yurself.
While the data they provided/reported of average tensile strength and moduli results per ASTM D638-77 did indeed as they concluded vary little at least over the 24 month diurnal exposures, a regression analyses, or fitted line plot I did and think anyone else could do of the mean (average) impact loss data per D2444-70 provided in this Uni-Bell report will reveal these pvc pipes lost on average about a fifth of their original impact strength with 24 months of aboveground exposure. It is further interesting the same technical report also happens to provide test data as well on a perhaps significant set of “control” pipes. After initial mechanical tests of one brand new pipe not exposed to any sunlight from each of 13 test batches was tested to obtain “datum mechanical property values“), “Another pipe from each test lot was placed in a storage location protected from all UV radiation, sunlight, and excessive heat.” This pipe was later tested as a control sample to provide data on PVC pipe aged two years without UV exposure.”
Despite some industry claims to the contrary there appears to be, per this report data and for whatever reason(s), even some at least slight natural aging or drop in the average impact strength (a measure of fracture toughness and tolerance for flaws and damages in the presence of impacts or stress), as well perhaps to a lesser extent average tensile strength of even the 13 pvc “control” pipes, even when said control pipes were reportedly “protected from all UV radiation” for only 24 months. The average drop in impact strength of the 13 control pipes was 4.4%, and the average drop in tensile strength of control pipes was 1.3% after 24 months of said "protection" from deleterious UV exposures. The actual raw data by site, and pipe by pipe for each of the 10-20 pipes per site/lot etc., was not provided in the report for either the actually individual exposed or control pipes. However, it was reported, “The lowest single average impact strength resulted after 8 months of UV exposure was 203 ft-lbf, or 96% of the initial ASTM requirement”, and also, “However, the lowest single average impact strength reported throughout the entire evaluation period was 139 ft-lbf following 15 months of exposure.”
I also know that a now ballyhooed "50 year warrantee" (established it appears in the face of some nasty ongoing whistleblower etc. lawsuits) from one pvc pipe manufacturer you can read at

http://www.jmeagle.com/pdfs/50-year-warranty-Limited.pdf

among many other things specifically excludes "U.V. degradation" from their new warrantee (it appears without quantifying exactly what they mean there - may be safe bet as I know past failures have been blamed on UV!) You thus might want to ask the manufacturer this question, or if that is not productive think about the other suggestions you've gotten here. [BTW if you end up testing, tarping, painting, or scrapping whatever this pipe you might want to factor in the cost and bother of this into next evaluation of competitive pipe materials, as I think it is not at all unusual for pipe to end up laying out in aggregate in many different yards or jobs for years. Also, very large tarps are not inexpensive, and won't last long either out in the sun!] Let us know what you find out, and everyone have a good weekend!

 

[dicksewerrat]

If you intend to use this pipe in a pressure system, you should get it tested and compare to new pipe before use.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[stanier]

Competent PVC pipe manufacturers in Australia supply PVC in crates wrapped in plastic sheeting that UV cannot penetrate.

After 5 to 7 years I would not trust the PVC pipe in a pressure system. If you test one sample who is to say its representative of the rest of the batch?

Confine it to gravity sewer use.

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

http://waterhammer.hopout.com.au/