PVC Piping Longevity

The first thing to do is the 12 missing inspections!

Any failures in the piping will present themselves as significant changes in the flow patterns and a drop in performance.

'Management By Walking About' springs to mind.

Early PVC Pipe used to leach the plasticiser causing it to go britle. This was fixed some 20 odd years ago yours could be fine. PVC deteriorates when exposed to UV unless protected. I suggest you do a visual inspection and if it aint Broke dont F***k with it but be prepared ie Budget to replace in the next 5 years and if it still aint broke. Go and buy beer and toast the PVC man that is a sure way to make it fail. Then you can look good when you are all prepared to replace it. Aeration both coarse and fine bubble types stress pipe quite a lot with constant vibration. I think if it was the old type it would have failed by now.

If you're willing to go into the aeration basin, cut off a section of PVC and test it against a new piece of PVC with a test machine to compare the fracture strength.

The air passing through the PVC pipe will actually wear out the inside of the pipe until it fails. I had this happen on a 4 year old system when it went it sounded like a shotgun. Forutnately no one was hurt. For saftey I would recomend replacing the entire system. Use copper if possible.

If you need something to protect the PVC from this point forward so you wont have any problems in the future, I work for a company who sells pressure sensitive adhesive tapes and we have a plasticized PVC pipewrap that is designed to protect piping from outside elements and corrosion.

You can take a look at the technical data sheet here.

If you are interested email me and I can discuss it with you further. Also, if you have any other PSA tape or custom die cut part needs let me know and I will be more than happy to help you out.

I assume that you are operating at relatively low pressures! I was taught that PVC piping should NEVER be used for air service, due to the potential for it to fragment and explode. When you look at replacing the pipe, which will probably be soon, consider HDPE, which IS used for air pressure service (and natural gas distribution)

Good luck!

PVC is routinely used in wastewater plants for air service. The air is generated by blowers, not compressors, a blower being an air-moving device that delivers a lot of flow at low pressure.

The pressures seen in the pipework are typically represented by the depth of water above the diffuser nozzle and the pressure difference between the inside and the outside of the submerged air pipes is usually too small to be of any significance as regards the longevity of the material.

At my work we use a lot of PVC pipe for seawater distribution. I found that as long as the pipe isn't exposed to the sun then what usually goes first is the fittings. We glue ours rather than using threaded fittings and this is always where the first leaks appear.

As for longevity it's quite hard to say. I've seen some PVC pipes which were installed 30 years ago and are doing just fine but on the other hand there are some pipes which are only a few years old and are failing. My advise is don't trust any arbitrary figure someone gives you. If you are concerned then do something about it. I would also agree with the last post about switching to HDPE. When PVC shatters it can produce some very sharp edges.

You might find some information on the PVC pipe association web site

www.uni-bell.org