ABS, ABS fittings, UV Resistance and Vanity...

Due to availability and vanity, I selected ABS tees for my patio drain inlets ref: the drawing below. PVC 4x3 tees don't seem to be available, and I figured that a black ABS interior under my brass drain grates would have a nicer appearance than bright white PVC.

...but then I get to worrying about ABS's ultraviolet resistance (or lack thereof)...

Should I just quit worrying? Is sun shining through the drain grates enough to degrade the ABS risers over the years? Options include a quick coat of UV-resistant spray paint on the riser pipe's interior, or locating some DWV PVC with the black interior (though I'm not sure where I'd find that locally, in the small quantity I need).

Also, it seems obvious to me that ABS fittings (in this case, the Tee and end cap) are not constructed of the same cellular core material that straight ABS pipe of made of. My assumption is these are hearty plastic with better UV resistance than the pipe, yet I can't locate any manufacturer data noting the difference.

I've got an email in to an ABS manufacturer; if I get a reply, I'll share it here. Curious to hear any of your thoughts on the matter.

Middle east is about to blow up. We will be putting Jack Daniels in our gas tanks. That's if the terrorists don't blow up the car!

We will soon be glowing in the dark when the zoomies from the jap reactor hit the west coast.

Liberal union thugs such as in Wisconsin are about to take the last few dollars I don't already pay in taxes.

YOU are worried about whether your patio drain will last 10 years or 30 years!

PVC has the same problem with UV. I assume you are pouring concrete around the drain, and if so, that would prevent any "fracturing" caused by the UV rays hardening the plastic.

Pretty much all of the UV resistant products like outdoor cable, cable ties, etc., are black so I would think black ABS might be more UV resistant than white PVC. I used cheaper white PVC underground to carry away the downspouts but didn't want to see white glaring at the ends where it came to the surface so I transitioned to ABS. After 12 years, the ABS looks the same as the day it went in. Also, my vent stacks are ABS and standing up well to UV.

Good to yours is holding up, LLigetfa, and hj, I've been reading all sorts of manufacturer data about ABS, PVC and UV rays that contradicts what you're saying and exposed ABS vent stacks must be protected with latex house paint, except "sometimes black UV-inhibitors are added," and I've never known an ABS pipe to not be black! Soooo... ???

I have this irrational concern is the short ABS riser will quickly degrade to dust, and not so much leak (which wouldn't be a big deal), but leave the drain bodies unsupported and somehow compromise the concrete poured around them. But, like I said, I don't *really* believe that's going to happen.

I'm just going to install them, and maybe based on what the manufacturer responds with I'll take a few minutes to dress 'em up on the inside with the rattle can. But other than that, I'll turn my concerns to more serious matters.

jimbo said:

Middle east is about to blow up. We will be putting Jack Daniels in our gas tanks.... YOU are worried about whether your patio drain will last 10 years or 30 years!

Click to expand...

A little perspective is alwasy good, right! This is a patio for the ages!

Here are some snippets of the reply I received from the manufacturer I emailed:

"UV Degradation or sun burning affects ABS when energy from the UV radiation causes excitation of the molecular bonds in the plastic. The resulting reaction occurs only on the exposed surface of the pipe and to extremely shallow depths of around .001 to .003 inch."

"ABS pipe and fittings are manufactured differently. Despite the differences in the manufacturing process, both the pipe and fittings can be adversely affected from UV exposure. Charlotte Pipe’s recommendation of painting with a water based latex paint would apply to both the pipe and the fittings that are exposed to continuous sunlight."

He also said that while impact strength and color are adversely affected, tensile strength and elasticity are not. So basically, it sounds like the plastic equivalent of surface oxidation. I'm going to install these pipe and forget about them.

See also "Weatherability of Thermoplastic Piping Systems" TR-18 2019
https://plasticpipe.org/pdf/tr-18_weatherability_thermo_pipe_systems.pdf
Basically carbon black is added sometimes, and helps a lot.

I just pulled a pretty damn brittle ABS vent pipe off a roof, I think it was there since the 1970's. The galvanized pipes from 1926 of course are completely fine.