how resilient is PEX O2 barrier?

ross

I have always wondered about the PEX that has the oxygen barrier sprayed on near the end of the manufacturing process. Can the barrier scrape off during shipping/handling/installation? What about just from rubbing from expansion/contraction in a staple-up job? Has anyone seen any signs that would indicate it has happened and been a problem? Just curious

John Ruhnke1

No problem with Wirsbo PEX

Ross,

On Wirsbo PEX the o2 barrier is installed some place in the middle. It is not installed on top of the pipe. I would ask your manufacture as to where the barrier is installed. I would imagine it is much cheaper to manufacture the pipe with the barrier on the outside. I am sure many manufacturers take this short cut.

JR

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Bill Wright_2

Actually,

The majority of the PEX manufacturers (including Wirsbo) apply EVOH to the outside of the tube. There are very few who protect the barrier between layers of PEX, but (for the same reasons mentioned in the original post) there will probably be several more PEX-EVOH-PEX products in the NA market within the next couple of years. It just makes sense.

Steve Bergerson

Wirsbo barrier

Has Wirsbo changed their manufacturing process?

When I took the factory tour a couple of years ago, they would take Aquapex rolls that were already manufactured and run them through a machine that sprayed an oxygen barrier on the outside of the tube and that set it in place with heat.... out came HePex.

John Ruhnke1

You are right about Wirsbo...

Sorry Bill,

Someone told me that the oxygen barrier of Wirsbo was applied in the middle. I asked them if they were talking about multi core and they said no. It was bad info. I called Wirsbo and RTI and found out differant. It is sprayed on. Pex Al PEX does have the oxygen barrier in the middle. How ever I have been told that scraping the pipe is not going to give enough surface area to make a differance as long as you don't go crazy. We are always carefull not to scrape the pipe for long distances. A little accidental scraping isn't going to make a differance.

JR

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John Barba1

O2 barriers

Greetings gang!

The barrier applications process goes like this:

Base pipe is run through a mild pre-heater, then the labelling is sprayed on, following by the barrier laminator. The laminator spray-laminates three materials onto the tubing. The first is an adhesive layer, next is the barrier layer itself. The final layer is a thin layer of PE to act as a sealer. This protects the barrier itself. Minor scratches to the tubing really are nothing to moan about when it comes to oxygen diffusion--a small scrape that actually gets through both layers will allow only tiny amounts of oxygen through--certainly not enough to cause any issues.

Hope this helps...

JMB

Mark Hunt

EVOH BARRIER

Just remember that regardless of how the O2 barrier is applied, it is the sum of the hole that matters. A few scratches and repairs here and there are not enough to matter. If you are using correct piping methods and using good air elimination you will not have any problems. Now if you were using totally non-barrier tubing that is a different story.

Bill Wright_2

Thanks John !!!

Terry

UV?

You may want to avoid leaving rolls of tubing or exposed tubing (to manifolds) out in the sunlight as the UV rays can damage the o2 Barrier's effectiveness.

KCA_2

And don't forget!

KCA_2

And don't forget!

KCA_2

And don't forget!

It is water soluble!!

:-) Kca