Why do they paint 2-inch pool pipes black? (just repaired with 2" white PVC)

[LM]

"The Effects of Ultraviolet Radiation on PVC Pipe"

Summarized by the PVC Pipe Association here: Further summarized by yours truly below: Q: What effect does ultraviolet exposure have on PVC pipe? A: Not much but enough to warrant a thin coat of opaque paint!

Modulus of Elasticity = unchanged after two years of sun Tensile Strength = unchanged after two years of sun Impact Strength = reduced drastically (by 75%) after two years of sun Structural Integrity = unchanged after two years of sun Pressure Capacity unchanged after two years of sun

The loss of impact strength stopped deteriorating as soon as the pipes were protected by the sun so it's directly related to the UV radiation.

Luckily, the presence of an opaque surface between the sun and the pipe prevents UV degradation, since UV radiation will not penetrate thin shields such as paint coatings or wrappings or burial.

Why black? What's more opaque than black? Electrical PVC outdoor pipe is gray. Go figure.

PS: I heard some paint won't stick to PVC so maybe you need special PVC paint?

[Elmo]

to Paint Your PVC Pipe Projects

Quote "I've had the best success with the Krylon? Fusion brand that?s formulated for plastic and PVC."

[JIMMIE]

I took out some PVC pipe that had been exposed to the sun for about 7 years. It was still doing its job but it was brittle as heck.

Jimmie

[JimT]

If it makes any difference mine are all still white. I don't remember seeing any that were painted any color. That's weird that it blew up. I had my waste valve closed one time and tried to back wash. I didn't have it on long so it didn't do anything. I'm glad you said something because I never would of imagined that could happen. I'll bet your motor seal goes out soon if it isn't gone already.

I'm always afraid I'm going to do something stupid like that.

[DD_BobK]

LM-

Super reply!

My landscape guy used white PVC (not sunlight resistance & unpainted) for an above manifold but placed such that it got very little direct sunlight.

After about 25 years, a narrow strip of plywood (3/4"x 3.5" x 96") that I Ieft on the patio cover blew off and hit one of the brass anti- siphon valves.

The PVC on the pressure side broke and I repaired with the grey PVC........ too lazy to rebuild the whole manifold in sunlight resistant PVC or copper. Maybe it'll last another 25 years? :)

cheers Bob

[Oren]

(Mohave Desert)

Okay I had to go look. My pool pump pipes are gray. Spears brand fitting, 2" PVC 1. Looked up gray pipe, it is SCH 80. My pipe stated SCH 40. So, I scraped it with my razor blade. Sure enough, the pipe is white. Looking further I found the blue glue. Some of the glue, painted gray looks like it is special - but not so. All this time I figgered it was gray pipe...

The supply lines for the solar panels are SCH 40, PVC1 painted a desert tan/sand color (eye appeal). Obvious the installer for the solar used a aerosol spray can. I can see some over spray on the gray.

A suggested paint for Lasco was to use a water base, white latex.?

[Brent]

Thanks for that information.

It's wonderful to finally understand what is going on.

Schedule 40 PVC is 40mm thick and the gray is for UV protection.

I think the riddle of the painted pipes has been solved! :)

[FLATSHIPP'N-N-HANDLING 99CENT]

no do not paint ! reason for black paint 2 much beer, attemtp to hide pluming. reason not to paint . ease of repair. never walk away after a repair , prime the pump and wait to see that every thing is flowing WITH NO LEAKS and the filter preasure is OK .you can turn pump on and off on and off and watch the pump as you do this (my trick) see leaks ? fix them.... remember a clean poool is a safer pool.... POOLPUMPREPAIRGUY .IN SUNNY LONGWOOD FLORIDA . where the pool is always open, come on in the water is just fine.. Jay

[mycomputer3]

Either you just invented a new way to heat water, or the FBI will come to your place to investigate the bomb you made and you'll be listed as a terrorist.

You should get help for your drinking problem...... I mean, how did you turn on the motor and not open the valves? It might be your medications too.

They painted them black because they did not paint them red, orange, green, yellow, blue, brown or purple. However, the person that said it's for UV protection, and I'd repaint them any color you like. At the same time, flat black will absorb more sunlight and make the water warmer. In your case, thats the last thing you need to do.

If that's a 2inch OD, then it's 1 1/2" pvc. Pipe is always measured by the ID size, with the exception of some of the soft copper tubing, which is one of the most confusing things a plummmmmahhhhhh has to deal with.

The black ABS fitting may not hold up, I'd replace it.