PEX vs PVC

mung · February 18, 2015, 09:50:15 AM

My current water setup is a mixture of several things and I need to make some changes to it.

While I understand that glued PVC joints would be prone to coming lose with the vibration on a bus, is there any other reason not to use it? There are now PVC connectors that are very similar to Shark Bites and aren't that expensive, so what is the difference between using those and using PEX with a Shark Bite?

To me the pros of the PVC so far are that it is a lot less expensive and a lot less prone to punctures and such. PEX is really meant to be run in walls so to me it isn't really designed for the bus environment either.

bevans6 · February 18, 2015, 10:32:18 AM

Having had both in my bus and other RV's, I find that PEX is far superior. PVC is more prone to cracking, fracturing, freeze damage and mechanical damage. PEX is designed for unprotected installation in basements, etc. PEX is actually a lot tougher than PVC, a hammer blow that will shatter PVC won't hurt PEX at all. I got a first hand comparison last spring when I de-winterized the bus and found a half dozen cracks (in fully drained lines) and ripped all the PVC out and installed all new PEX. I would personally use the solid fittings and the correct band crimps, installed with the correct crimping tool. I got the one for the solid band crimps, but in hindsight the cheaper pinch crimps would probably have been just as good, and easier to use. I do use Shark-bite for some joints where it's impossible to get the crimp tool in and I didn't think the work through before-hand.

My PVC was the white hard plastic stuff, fwiw, maybe there are different types.

Brian

eagle19952 · February 18, 2015, 10:43:37 AM

PVC and Polybutylene pipe have been in my bus for ever. I would not wish to have the Polybutylene pipe were i building today and would replace it with PEX if the need arose, but it has not.

PVC does not often get whacked by a hammer

if freezing is not an issue, go with PVC

mung · February 18, 2015, 10:51:53 AM

While the weather here in Florida today does feel like below freezing to Floridians, the water isn't going to get cold enough to freeze.

bevans6 · February 18, 2015, 11:01:02 AM

Go for it then, use what makes you happy. PEX makes me happy, I look at those blue and red pipes and feel very happy that I finished that job and don't have to do it again! FWIW Shark-bites are fully compatible with both the PVC and copper pipe, and you can use them to make transitions between the different types of systems. I do recall reading that the current PVC is improved from what was around 15 years ago.

Brian

mung · February 18, 2015, 11:04:23 AM

The new PVC is a bit better and with 1/2" it is a lot more flexible than bigger sizes.

Iceni John · February 18, 2015, 12:10:38 PM

If you're worried about PEX being damaged, it's easy to run 1/2" PEX inside 3/4"-ID metal tube such as EMT. I did that where I have long unsupported runs of PEX across the tops of my luggage bays, using some pieces of anodized thin-wall aluminum tube from IMS's cheap bin. You could also use flex conduit to protect PEX, similar to how I put 1/4" DOT nylon airbrake tube inside 3/8" aluminum flex conduit where it could possibly otherwise by crushed or damaged.

John

luvrbus · February 18, 2015, 12:22:28 PM

Sharkbite fitting compatible with cooper and Pex will only work on CPVC not the standard sch 40 white stuff fwiw ,lol the RV industry is still using the gray Poly pipe ban from housing 20 years ago

Melbo · February 18, 2015, 12:23:03 PM

Pex is approved for water distribution while PVC is not. I would avoid PVC if it were mine but it is not. Pex properly installed in my opinion is the way to go.

HTH

Melbo

lostagain · February 18, 2015, 12:30:42 PM

Doing plumbing nowadays, Pex is the only way to go. I would not even protect it, it is so durable. Unless you are afraid of hitting it with a chain saw, or the like

JC

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mung · February 18, 2015, 12:31:23 PM

I should clarify that it would be 1/2" CPVC not standard sprinkler PVC.

eagle19952 · February 18, 2015, 12:31:28 PM

Quote from: Melbo on February 18, 2015, 12:23:03 PM
Pex is approved for water distribution while PVC is not. I would avoid PVC if it were mine but it is not. Pex properly installed in my opinion is the way to go.

HTH

Melbo

Where..

PVC piping is recognized as acceptable material for DWV, sewers, and potable water services and distribution in all model plumbing codes. These Codes normally identify acceptable products for specific uses based on the ASTM Standard designation

mung · February 18, 2015, 12:33:17 PM

Don apparently the reason they frown on using it inside of dwellings is that they don't want plumbers accidentally using standard cold water PVC on the hot side.

eagle19952 · February 18, 2015, 12:35:27 PM

Quote from: mung on February 18, 2015, 12:33:17 PM
Don apparently the reason they frown on using it inside of dwellings is that they don't want plumbers accidentally using standard cold water PVC on the hot side.

A licensed plumber would not do that....would he/she ?

Melbo · February 18, 2015, 01:44:23 PM

I of course am familiar with what is acceptable to the inspectors in my jurisdiction and was referencing that. There is always the minimum standard and if that works for you go for it. As I said it is not mine. You would be surprised at what licensed tradesmen do all the time.

Melbo