PEX vs Copper

[dfrahm]

I have been asked by several contractors to approve the use of PEX for domestic water piping in a commerical food/beverage installation. Piping will be hot, cold and filtered water. Filtered water may be re-mineralized RO. Piping will be run above and below grade. Contractors are saying the material and labor is less expensive. My questions:

1. Is this material suitable for this application?
2. If so, what are the installation concerns?
3. Is it less expensive overall?

My big concern is installation and sloppy connections. Assume that construction supervision may be lax and testing may be sloppy.

Thanks,
Dan

 

[DonPhillips]

Try looking in the IPC and on the NSF website.

Don Phillips

http://worthingtonengineering.com

 

[idunno09]

I am a plumber by trade and would like to give you my input. As to my understanding Pex pipe may not be used unless it is fire rated in a commercial building. I may be wrong about this as my company does only commercial and the only time we have ever used pex (besides trap primers) is in temporary water to a site.

To answer your first question you must think about how long the runs will be. how will you insulate it?

Second answer is that it does tend to look very sloppy, especially if using fire rated wirsbo, as it does not like to be straight. pex is easier than copper as it is much more forgiving, but that may be a bad thing as it could result in sloppiness by the worker, (easier work means less concentration which means, "whoops i for got to clamp that coupling, now we have a big mess.) Also it is harder to fix a leaky joint, but not a lot harder.

pex is definitely cheaper than copper, but the fire proof stuff is more expensive, but still not as expensive as copper.

So basically if it is a building larger than a big house go with copper, but if it is a small ommercial building is really see no problem with pex.

 

[ChrisConley]

Have you considered CPVC for domestic hot and/or cold? I've been allowing it is an alternative to copper (which just keeps getting more expensive). The material cost isn't a whole lot different, but it is solvent welded and light. The pipe wall offers enough insulation that you may not require insulation on cold pipes, and less on hot pipes.

I like it as it feels like a bridge between traditional copper and sloppy PEX.

http://www.ipexinc.com/

 

[DonPhillips]

PEX can be used in many commercial buildings, depending on construction type. Types III, IV, and V all allow combustible materials like PEX. Type I and II is noncombustible construction and PEX would not be typically permitted.

Don Phillips

http://worthingtonengineering.com

 

[moltenmetal]

Wow- you've got to fireproof the water lines in multi-unit residential complexes? Why on earth would firefighters want THAT? Surely, a burst water line would occur only where there's a fire, which perhaps might aid in actually FIGHTING the fire?! Are they worried about unit-to-unit water damage? As if the sprinkler system doesn't already cause THAT in spades...

Seems a very silly rule on first glance. Perhaps someone could explain what the fire/building code officials are after in making such a rule?! Are they worried about the pipe itself being a firespread risk? No risk of that with PEX- it's no more flammable than any wood product, surely.

PEX, particularly the non-composite stuff (ie. without the aluminum core) seems to me to be the definition of "fit for purpose" for potable water: PEX is durable, easy to install, totally corrosion immune in the run of the line, damage-resistant, freeze-resistant without bursting, and properly installed, comparatively free of joints in hidden spaces. Theres at least 50 years of installed base experience with it, so there's no need to worry about it becoming another polyisobutylene fiasco. It saves significantly on both labour and materials during the install relative to copper. I did the rough-in for the hot and cold water systems to a kitchen and bath in my house addition using homerun Wirsbo (Uponor) PEX in about 2 hours and it was 100% leak tight first time- it would have taken me days using sweat-soldered copper. The only downside is the cost of the tooling if you're a DIYer.

Some plumbers love it because it's fast and cheap. Others hate it because it takes the "craftsmanship" out of their work and "looks sloppy" because not everything is plumb and level when you're done. They tend to prefer the PEX-Al-PEX composite because it can be bent to look like pipe.

 

[zdas04]

I was really wondering about the tone of this thread, thanks moltenmetal for pulling it to the other side. I'm a fan of the "This Old House" program on PBS and they've been using it in preferentially their residential projects for about 10 years. When they first started using it they talked (then) about the 50 years of experience that existed in Europe for home construction. I figure the reason US plumbers haven't rushed to it is that it can turn a 2-3 day job into a 3-4 hour job, a lot less billable hours. I know some plumbers who recognize their backlog and job security and are recommending it, but they seem to be pretty scarce.

I've considered it for temporary sight glasses on tanks, but I haven't been able to determine its resistance to chemical attack from petroleum products (the literature I can find is all about corrosion resistance and applicability to potable water service).

David

 

[DonPhillips]

As buildings grow in size and the danger of collapse onto firefighters becomes greater, the building codes limit the building to noncombustible types of construction. This prevents building components from becoming fuel for the fire, and gives the structure more time for the firefighters to either fight the fire (offensive operations), or to evacuate the building and start defensive operations.

Plastics - not just water lines but electrical conduit, wire, low voltage cables, etc. do not have to be fireproof, just non-combustible, like copper, steel, etc. Plastic pipes will become fuel that feeds a fire or generate a tremendous amount of smoke, which tend to hurt more people than flames.

The intent is to limit the hazard as buildings grow larger. Similarly, in addition to the 5 types of construction, the structural elements are either protected or not. For unlimited height and area buildings - which allow high-rise buildings to be built per the codes - the columns, beams, slabs, etc. may be have to be fire-resistant so that a burning building continues to stand for 1, 2, or even 3 hours.

Hopefully, that explains the intent of some of these code restrictions. Many lives were lost over many decades in horrific fires that led to the formation of these codes as we know them today.

Don Phillips

http://worthingtonengineering.com