Type of pipe?

Brad White_9

at least here in MA, of the copper piping available, only Type L or Type K copper are permissible per the plumbing code. The thicker walls resist velocity erosion better; that is the reason. All are the same material, just wall thickness is different. OD is the same, ID changes. Type M has a larger ID than L which is larger ID than K.

Your local code may differ but it is the best practice to use at least Type L.

Given the code choice of Type L or Type K, most use Type L (economic reality, especially nowadays!). Type K for buried lines. Type M is not permissible for domestic H & CW but is fine for heating.

Until recently, I always used Type L for both domestic and heating. Recent price increases forced my hand to downgrade the heating piping only to Type M (and Pex-Al-Pex of course).

MTess

Pipe type.

Conflicting opinions say that type M copper is insuffecient for hot and cold water lines. Is this true? Should the have used type L? What is the difference besides thickness?

Any help would be greatly appreciated.

Al Letellier_9

Type M vs. Type L

I agree with the previous post that L is the better option for durability and corrosion protection. Type M is allowed by code here up to 100 psi and a lot of plumbers use it to save a buck...we rip out a lot of it. Use Type M only for heating or for safety drips, etc.

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[Deleted User]

In Colorado...

I've been using type M copper for potable water piping forever (33 years) and other than sone grossly oversized, continuously run circ returns, have had ZERO failures of the tubing. Stop and think about it for a second. Which system is going to see more "flow" time, a space heating system or a domestic water system.

For me and my money, and my house, type M is just fine provided that the designer/installer is paying proper attention to correct tube sizing procedures and avoids excess velocity issues.

I suspect the required use of L back east was influenced by their extremely soft water which won't allow a protective patina to be set, and allows the alum used for water treatement to get a foot hold and cause cold water pitting and premature pipe failure.

Out west here, our water is harder and it is not an issue.

When a trades person moves from the east where he is used to doing it a certain way, when someone proposes something different than they are used to, it usally raises the hackles.

Check with your local code and do what they recommend.

ME