PEX = bad and COPPER = good

Richard Miller_2

This is being promoted in some circles as a definitive argument against PEX. I would appreciate your analysis of their claims.

http://www.radiantheat.net/tubing_main/

kframe

Interesting, but I think they're ignoring a lot of factors, glossing over others, and simply BSing on yet some others.

One factor they're ignoring is that some of the original PEX systems were installed in Europe nearly 60 years ago and are still operating trouble-free.

I think they are also BSing on the "burying copper in concrete" factor. I'm hearing more and more information about how copper systems buried in slabs are failing at alarmingly higher rates as they get older.

I'm also kind of dubious about the claims about pressure ratings as a performance safety factor. If that's such an issue, then a TPRV can be installed on the distribution manifold as a secondary safety.

I'm also quite dubious about the claim that balancing with a copper tube system isn't required.

To me it sounds as if the contractor is an "old technology is the best technology, nothing new can replace it" type of contractor.

I'm as leery of those kinds as I am of contractors who push the newest and greatest, but unproven, technology.

Pex, though, is proven technology, with a long and successful track record.

Caselli

Huh ?! ?! ?!

"....Both supply and return manifolds are required in plastic and rubber systems while only a return manifold is needed for the copper system. In fact, a properly designed copper tube system will allow efficient and even heating of the conditioned space without any balancing requirements, whereas balancing is always required in the plastic (PEX) and rubber tube systems. The return manifold in the copper system is used only for personal comfort, i.e., reducing the heat within a zoned area, not for promoting heat. This situation lends favor to the copper system because the heating of the structure is relying on the design and not the balancing at the manifold. "

Richard Miller_2

huh? II

What are these guys talking about? I missed that part. The closer I read it the less I am inclined to give this guy the benefit of the doubt. Some of this is awfully close to fraudulant in my opinion. To blatantly lie in order to sell your product and put down another's? Aren't there laws in CA against that?

hot_rod

Lots of truth

in what the state about copper. My experiments prove coppers excellent heat transfer vividly.

Here is the biggest challange with copper in concrete, in my opinion. As we all know in a perfect world all the tube used in radiant slabs would be completly encased in the slab. In reality this is very hard to accomplish. On my last two large commercial slabs I went to the expense of using continous rail chairs. I found even with chairs every 4 feet the tube would still sag to the bottom of the pour in between. I suspect soft copper across these chairs could kink if a 250 lb concrete guy stepped on the tube next to the chair. Who would know???

It is very easy to ask, plead, beg the concrete guys to lift the tube. Fat chance! Ever see concrete flow from a pumper truck? Not the best enviroment for lifting tube. Lots of weight and mass in an incrediable short period of time. We had a seven man crew on the last job, still they couldn't possibly keep up with one pumper on slow speed. These guys get paid by the square foot installed. I suppose for twice the money they would stop the pump every minute to lift tube Not likely. Also it is easy for them to over lift causing the tube to be in harms way when they saw cut the expansion grooves!

It's the contact with the soil that can have the biggest effect on copper life expectency, in my opinion. Also redi mix plants all use fly ash in concrete. Some of this ash mix, especially in moist enviroments, will attack the copper. The ash from high sulfur coal plants can be very agressive to copper.

My reading, on other plumbing lists, indicates a high failure rate for copper in slab plumbing. Largly in California where slab constructioin is common. In fact entire industries are built around slab repipe and pipe lining tech. Again mainly a soil and concrete issue. Some suggest the fertilizers added to lawns or spread on farmslands over the years, which turn into subdivisions, are a main cause.

I also read a thread, posted by a CDA fellow, concerning "thermogalvanic corrosion" which is caused by dissimilar temperatures between cold and hot lines running along side one another in a slab!??? Presents itself a pinholes in hot lines only, as the hot tube becomes the anode in this type of corrosion. Certainly a real possibility in radiant copper slabs.

All things considered I feel the PEX still has a decisive edge for in slab work. But check back in 20 years

hot rod

Tony Conner

There Is...

...no single material that is the right one to use, all the time, in every application, everywhere. Mechanical failure, corrosion/degradation factors are interwoven, and why a particular material fails in a given application is often not understood very well, or worse yet, misdiagnosed altogether.

Manfacturers very much tend to put the very best spin on their products, while glossing over shortcomings. That's not new - it's always been that way. That's why the Romans coined the phrase "caveat emptor". (And THEY probably stole that saying from somebody else.)

I think there will be plastic system tube failures. I think there will be copper system tube failures. Some by reason of crappy product. (There's been trouble in plastic/rubber tube-land, and a few years ago, a big copper pipe maker got busted for making and selling short-weight pipe.) Some by reason of faulty design. Some by botched installation. Most by a combination that will be shades of grey.

Read, think, and decide for yourselves. Ask questions as to how something was calculated - don't just accept what somebody says. To blindly believe what you're being told by pretty much anybody, just has "trouble" written all over it.

I used to work in the power generation business. There were 4 utilities that all claimed to be "the biggest". Three of these guys had to be wrong, right? Nope - they were ALL right, based on what they were using for a yardstick. "A" was the biggest based on the most customers. "B" was the biggest based on the most transmission line. "C" had the biggest gross revenue. "D" had the most installed megawatts of generation capacity. Ask how things are being figured out, because the method really DOES matter. Figures don't lie, but liars can figure.

Richard Miller_2

I agree with you.

And my point here is not to knock copper. I think though you should be honest about what you present to the public and this site is full of incorrect information. Some is so far off I wonder if it is intentional!

kframe

Same here, I'm not knocking copper.

In fact, and this is my dirty little secret, I find one of life's greatest small pleasures (at least for me) to be laying out and assembling copper piping. There is something so incredibly satisfying about sweating a good copper pipe joint...

But, this site is pretty uniform in its pillorying of Pex, essentially presenting it as a product with no benefits. That's simply a lie, in my opinion.

You know, I wonder if the galvanized pipe people had the same things to say about the copper pipe people when copper began replacing galvanized as the home plumbing piping of choice...

corey

Galvanized

Funny stuff. My grandfather has a house built in 1950. Galvanized water supply pipe still intact. Cut some out recently to replace a valve, and to my surprise it was in fine shape.

A friend has a house built in 1979.
Copper pipe had eroded through by 2002.

No absolutes in life. "Your results may vary..."

hot_rod

I worked on

a 1950 vintage black steel pipe system a few years back. The only reason it failed was a section of pipe had been lying in a wet area, under a bath tub with a leaking drain. The pipe rusted out along the bottom. In other areas that I chopped up, the tube was like the day it was installed, both inside and out!

I still think it has a lot to do with O2 through the tubing wall. Failures in PB and other non barrier systems are proving out this theory over and over. Hope the current O2 barrier methods are in fact protecting our systems

hot rod

kframe

My parents live in a 1903 AmVic that my Grandparents originally bought in 1943.

The piping is a combination of lead, cast iron, copper, and PVC waste, and the supply is a combination of galvanized, copper, and PVC. My Grandfather, a mechanical engineer, installed some of the PVC in the early 1960s; it may have been some of the first PVC installed in the entire town.

I'm hoping that I'll be next on the list of owners when my parents decide to get rid of the place.

If I'm in a position to, I'll renovate heavily, and probably finish ripping out the galvenized and replace it all with Pex. :-)