M versus L copper tubing


I went to the local Home Depot to get all the things that I needed to install new copper piping to my new shower/tub valve I bought yesterday. Told the guy what I was doing, showed him my sketch, and he happily sold me 20 feet of 1/2" copper tubing with the neccesary couplings. I mentioned to him in the store that I was amazed that the stuff in the rolls was 4x more expensive than the rigid 1/2" that he sold me. He smirkily said "yeah, isn't that something?"
When I got home I researched the difference, and found that he had sold me 1/2" M rated copper (under $5 per 10 feet), versus the other 1/2" L rated ($20+ for 10 feet) that I had noticed. The sites that I read online about the stuff say to only use the thin wall (M) for vents and other "light duty" piping, and to use medium wall (L) for water supplies.
So am I out the money I spent on the M piping, since I already cut the stuff? This is a house that I'm finishing up to sell next month, but I would hate to think that the new owner is going to have problems soon after... What are your thoughts on using the M rated copper on supply lines to the shower/tub valve and the lines from the valve into the showerhead/tub spout?
Oh, and I checked the copper that was already in the walls of this 21 year-old house that has never had a leak. You guessed it... M rated. Hence, my dilemma :-)
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The $20 for 10ft of copper was probably the price for soft copper which is sold either by the foot or the whole roll itself.
The average price for a 10ft length of rigid 1/2" L copper should be around $7.50
M copper is fine for your shower. One of the benefits of L copper because of the thickness, is that it helps to absorb more sound.
Nick

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Thanks nick,
I was more worried about failures than sound, so I'll go with the M copper. Thanks for the price comparison also. I hate going in to buy stuff that I have no idea what the average price should be... makes me feel like my wife is at the car dealer ;-)
Orko
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nick is an idiot. You always use L on domestic, unless you are a cheap loser. Sound is NOT the reason. You must not have very hard water if your M is fine after many many years. I have seen M rot out in 5 years. You have made a common do-it-yourself mistake. Never take plumbing advice from a home cheapo reject. You are pretty cheap or really stupid if you are willing to pay more for 1 month of cable than you are on your pipes which will be there for many months.

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I guess I'm a really cheap, stupid, loser then. Wait, you must be talking to Nick ;-)
Anyway, the pipes are in and I'm happy enough with it to sell my house. If it leaks in 5-10 years, the house will be 26-31 years old and the new owners will probably not be too surprised at that point. Since the whole house is plumbed with M, it doesn't make too much sense to make my 6' of pipe to last forever only to sell it with 98% M piping anyway.
I'll keep your advice in mind though when I do any future work. Thanks!
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"Ned Flanders"
Ummm....type m copper is the standard around here for water lines.
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I would never use m on a well 4 out of 5 here use L

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I just walked in on this thread.
I am shocked SHOCKED to see all my bright buddies here replying as they have ! Read your codes ! '' M'' is for radiant heating. Its cheaper as its a thinner wall. Read some copper pipe web sites ! '' L '' is for potable water. Ok ?
No problem ...eh ? Heh...Ok, what if the home is inspected before you sell it ? It won't pass inspection and the hell with it if my code is not in your jurisdiction. Mine was made by the US Gov. during WW II and can be used in any court. Be ready to pay for a pro to come and replace all the copper in your home and to open it for complete plumming inspection. You will have to replace M with L or drop the price for repair accordingly. Yeppers, you could of got your money back. The guy mislead you on the copper and the codes. Just because there is a lack of enforcement in your jurisdiction does not make it law.
Yo ! What about all the past posts that everyone claims has *pinholes in the copper ? I never seen pinholes, but I do understand why you have it.
Rolled copper is *most likely to be type '' K '' for underground and is a heavy walled pipe.
M has red writing on it a continuous line on the pipe. L has blue. You can feel the difference just by touch. There is hard and soft copper, you know that even type K soft if run as a vertical line it must terminate before a change of direction fitting is used.
You know of DWV copper. All copper is color coded just to prevent what this guy did.
( Where is Hot ? You people are back sliding. AW come back and make these Plummers fly right.)

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Red,
I went and read some copper pipe web sites as you suggested and got really confused. Some say that L is suggested, others say that L is required, and others say that M is the minimum required for potable water. Ack! I'll try and post this on another board and get some more feedback
See: http://www.copper.org/resources/pub_list/pdf/copper_tube_handbook.pdf which I found on copper.org, the CDA website. They say to use M rated if I'm reading it right. Ugh. The piping is in, tested and sheetrocked. I'm having a real hard time thinking that I'm going to have to go in there again to sweat new type L piping onto the existing M rated copper? I would hate to fail inspection, but I'm not sure how they would be able to see it since its all behind sheetrock and my house is sitting on a cement slab with no crawlspace.
Thanks for all your help. Any other viewpoints would be appreciated.
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M copper is FORBIDDEN for domestic potable water. All codes come from the original code made by the US gov. around WW II. Codes are laws. You can't win in court if you stick type M in for potable water.

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On Thu, 26 May 2005 12:05:38 -0700, Red Jacket wrote

Red Jacket,
I realize you think you know all the answers but you're wrong, wrong, WRONG!! You'll get no argument that Type L is superior to Type M copper tube because of the thicker wall.
However the Uniform Plumbing Code in Chapter 6, lists Type M copper as suitable for potable water systems as long as it remains above ground. It has been so since at least 1970
Am unfamiliar with requirements in other CURRENT codes but would be surprised if they differed from what the Copper Development Association recommends, which is Type M for ANY aboveground potable water installation.
Doug
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"plumbguru2"
Thank you for restoring sanity. My faith is restored.
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heh...time for a Prozac Mike.

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I'm right. Read up on it. I'd dispute you in court. Its the reason we see ' pinhole' posts only here. Thicker is the reason. Copper cannot be made hard by proper ( cheaper) metallurgy means. Hammering & heat.

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"Red Jacket"
It's one thing to say "I'd dispute you in court," and another to say "it's not legal." Type M is legal, and most contractors use it in residential homes (at least around here) with no problems.
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Its simple Mike. They're wrong, you should* not be. You're smarter than they are. You're a Plummer.
Take some time and study copper. I agree its 17,000 years old and not mined by the Ojibwa, but Mediterranean people in the lake Superior region. Its been found in graves from that time, so its healing power was known then. ( not proven tho.) It not a weirdo theory, its real archeological history of the Mn. area. No one can figure out the cu mines there.
Its a fascinating history anyway you look at it. Its good background info. One book is '' Kitchi-Gummi.'' Few people ever looked at the copper trade. I'll look up another professor of Archeology for you later.

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