I vote for L. One of the benefits of DIYing is that you can use a
little higher grade of material than a contractor worried about bid
price might propose.

http://www.sizes.com/materls/pipeCopper.htm#DWV (and I don't know
who's behind that site) speaks of L as the normal "most purposes" pipe
- but of course M is very, very common in household use.

That site also has a nice table by which you can compute inside
cross-section areas, which would be the primary determinant of flow
rates (area=3.14 x (half-the-diameter)-squared, but you knew that). By
may calculations, L has 6% less area than M at the 3/4" size, 8% less
at 1/2".

Chip C
Toronto

"art" wrote in message .. .
M type is for heating lines, L is for "normal" house plumbing. K is for
special applications. K is generally only available at plumbing supply
houses and K is much more expensive. Use L...




"Paul J" wrote in message
om...
I am ready and about to buy materials for the repiping from galvanized
1/2" to copper ?", but what size to use? I would like to go with 1/2"
type K but that takes up more inside diameter then M and L. Should I
go with 5/8" K, 3/4" K or just not be worried about the inside
diameter because it is a very small difference? Then again the
galvanized pipe probably has only an 1/8" openning anyway from all the
years of crap in it.