Backyard Aquaponics
A place to discuss aquaponics

Does anyone have a guesstimate as to how long standard 80psi PVC will last exposed to sunlight? I know it will become brittle with time, but don't know how long it will last.

I assume that painting exposed portions would extend its life outdoors. Anyone have horror stories of pipes bursting or tales of year's worth of use from pvc?

After some hefty searching, I finally answered my own question:

http://www.pwpipe.com/literature/tb/tb-d9.pdf

Basically, impact resistance falls sharply, but other measures don't. It recommends painting with an exterior grade, light colored latex paint.

Still willing to hear those stories though!

no terrible stories here yet. I've been running some stuff for a few years. And I've been too lazy to paint the pipe.

Most PVC pipe is UV stabilised... well pressure pipe anyway...

It's very much related to temperature.

I have pvc pipe that it exposed to sunlight with water running through it. No discoloration, no brittleness etc. Also have pvc pipe the same age sitting on the ground for the same mount of time, getting more brown by the day.

Not sure if it is a horror story or not, but when I purchesed my house 10 some years ago, I stripped it down and replumbed the whole house with PVC. I put a spicket on the outside where the water mains entered the house. One day my daughter went to turn it off and snapped the pvc clean off at the 'T' the spicket was attached to. I had a shut-off at ground level just below that so it was not to hard to fix, but I almost had to open up the wall to get to a clean enough piece to be able to re-glue it. So - less then 10 years in the sun will certainly make it brittle. Never had any trouble with any of the stuff that was burried or in the walls (so far).

My system out the back has PVC pipes exposed, and it's been there for 6-7 years without a problem. I've been in my house for 11 years and there are sprinkler risers that are standard white PVC pipe which are fine. Don;t know when they were installed, a long time before I bought the house, but then I probably haven't put any pressure on them either.

Not all PVC is the same, some is suited to outdoor use and is UV stabilised. I think Storm and DWV is OK, but most pressure pipe must be painted or buried
Basically plasticisers (things that let it flex) migrate out of the material and it becomes back to base material which is highly brittle. Some types have UV blockers but these too fall to bits after a few years.
You arent supposed to sell PVC that has been in the sun for more than around 12 months.
Cost is a pretty good indicator of high quality additives (plasticisers and blockers)or crappy ones

the hard part is that the pipe isnt really under any pressure as each GB has escape holes the the air get released from then the water comes out to water the plants.... If you are worried about the pressure build up just put a t piece in after the pump and have it running back into your fishtank that way No pressure to blow pipes and the EXTRA benefit of more aeration of the water and swirling to get solids to the middle ....and extra fun for the fish to swim against the current...

Based on the research paper (above) - brittleness is only in regards to impact resistance, not to pressure. So even a sun exposed pipe shouldn't collapse under pressure (which makes sense due to the nature/shape of a pipe) up to its advertised limit.

I figure to be safe, its easier to paint any pipe. Bumping into one would be all to easy while working. It will also blend into the yard instead of standing out in high contrast.

I had a run of 25mm white irrigation PVC along top of fence at side of house for about 8years. About 15m or so where it was paved and too much effort to dig up.
Only just removed it, bit brittle but still was fine.
Mains pressure was only on it when the irrigation was on due to a master solenoid.