PEX confusion

[XCOTT]

Hi, 1st post.

The existing plumbing was a worrying mashup of galvanized and copper. No hot in the kitchen, no cold the in the bathroom sink, and the cold in the shower decreasing in pressure, rust stain in the toilet. etc. The house is single wall, raised with the pipes in the crawl space underneath. I decided to go with PEX to bypass the old pipes to return function and safeguard against an emergency repair(pipes had failed in the past.) Everything installed without issue.

I did my homework(tried, anyway) before beginning. I thought my main concern was avoiding direct sunlight. In the evening, the sun hits the back of the house where the system/manifold is currently mounted. I tarped off the area so there is no direct contact with it or the pipes.

Then other opinions started to emerge: no indirect either, and no LEDs. And conflicting opinions.

As it is now, the pipes are entering through the windows, at least until the old pipes can be removed. I was weighing the options of final configuration. but if I ran the pipes under the house where no direct light ever reaches, but it is lit by reflected light, do I need to be concerned? Is ambient UV a thing? Is latex paint an effective solution, any downsides? How about black heat shrink tubing? do I need to to cover/coat the the entire length or a certain distance away from the direct light? I was also thinking of running it thru electrial conduit pipes.

Does it basically need to be in complete darkness?

I did install it knowing that it might be just a stop gap, not that I like to burn money. If there is a chance of getting a good lifespan out of it, I'd like to try.

 

[JG plumbing]

Pipe needs to be insulated anyway. Insulate it.

I'm not sure indirect UV is a thing.

UV is the issue, not all light, as far as I know.

 

[XCOTT]

Pipe needs to be insulated anyway. Insulate it.

I'm not sure indirect UV is a thing.

UV is the issue, not all light, as far as I know.

Re insulation, both pipes? Does it still apply if I’m in a tropical climate?(Hawaii, one of the hot dry areas…not near a volcano )

Also, all fixtures are less than 15 feet from the water heater.

 

[JG plumbing]

Yes. Cold water in a hot or warm room will cause condensation unless there is an unuaslly small amount of moisture in the air.

Besides what does it matter if you "need" it or not? You still need it to protect the pipe from light.

 

[Twowaxhack]

Paint the pipe with latex for uv protection.

I’ve found UV damaged pex that was under the edge of a house that was not in direct sunlight.

 

[PerplexedPlumber]

Indirect uv would be like sunburn on a cloudy day. Fluorescent light is a source of uv, which can be refracted from other surfaces in a room as "indirect uv". LEDs can also generate uv; it has been a while since I looked at how much relative to other lights. Be sure if you paint to use water-based latex per 2Wax suggestion. There are also thin, flexible plastic sleeves that you can run the PEX through. Insulation, as JG mentioned, will also block light, if you turn the gap to the back and tape it at seams. Another temporary option to consider would be to cover all of that with a sheet of exterior radiant barrier insulation, taping it closed. If the "final configuration" will be completed in 30 days or so, and that part of the PEX will be destroyed, I would go with cheapest, least effort solution.

 

[Twowaxhack]

Insulation is not UV resistant.

Last I checked it costs more than the pipe does per foot

 

[JG plumbing]

Insulation is the common practice industry wide. It's also code. Every professional plumber insulates pex for many many reasons. No one would paint it. Pvc gets painted from time to time for the same purpose. I agree if someone were silly enough to paint it water based latex would be the way to go.

As far as the indirect sunlight I think it would be more like getting a sunburn in the shade or through a window. I'm not totally sure. Water vapor or clouds do reflects UV. Which isn't the same as indirect in my book. I have heard of floors being ruined thought a window though.

 

[JG plumbing]

It's also exceedingly common to put fiberglass insulation on piping that is outdoors.

 

[PerplexedPlumber]

There are also two different types of pipe insulation products, one that is a black polyethylene foam and one that is a soft, black foam used outside, such as for HVAC units. Either should be OK for a short time, and I think this is supposed to be short-term, which sometimes turns into loner-term. It probably does cost more than the PEX, but shouldn't be much for the total amount still. A small roll of radiant barrier may cost less. The fiberglass pipe wrap that has a foil exterior film that JG mentioned would work for a long time, and it probably would be the most economical.

A good reason to insulate cold water PEX would be to curtail condensate in a humid environment, or to keep light from getting into a line that may have been exposed to algae.

 

[Twowaxhack]

Living here on the gulf coast and working in water front communities for years we find that painting pex, pvc and most any type plastic protects it from UV exposure.

Insulation deteriorates and gets torn up by wildlife building nests.

So for Uv protection paint is the best option. Insulate if you want but it’snot suitable for UV here for long term use, maybe a year or two.

insulation costs more than the pipe........

All of what I’ve said is particularly true on boat houses and piers out over the water......

 

[havasu]

Speaking of painting PVC, does the color of paint matter? All pool equipment I've seen have flat black paint on the PVC. This house has a beige paint. It seems to work good, but wonder what the experts think?

 

[JG plumbing]

I don't think color matters. Black absords heat more than lighter colors. Some colors blend more than others, those would be my guesses as to color.

 

[havasu]

That's what I thought. Thanks for your input.

 

[XCOTT]

I can't offer much as an amateur plumbing, but as a (former) professional illustrator, I can offer some food for thought. Contrast, not necessarily pigment, is something to consider for what you choose. Painting white on white will make it hard to tell when you have coverage as well as desnsity. Certain pigments(colors usually) tend to be weak, others transcluscent. I don't know if fading would pose anouther problem. White as a base is probably a given. Black has great pigment density but and mentioned, would absorb heat.

If I had to choose a best bet, least effort, I think gesso with a touch of black for contrast, would give excellent adhesion and opacity. Latex can be caused to release from plastic when wet, especial if the seal is broken. The gesso I have has held tight even when watered down to extreme amounts.

NOTE: I will have to test this in the case of PEX to see if it bears out.

 

[SHEPLMBR]

Why not just sleeve it with pvc?

 

[JG plumbing]

Why not just sleeve it with pvc?

As long as there are no fittings.