On Aug 13, 7:42 am, "Robert11" wrote:
Hello,

Live in a 35 year old house outside of Boston.

Had a leak in a Copper water pipe that the plumber finally found.

Unfortunately, I forgot to ask him if it was in a hot or cold line, as this
might, perhaps, be meaningful ?

Anyway, what surprised me was that it was pinhole leak in the middle of a
run.
Not at a joint or fitting, etc. Right in the middle of a line.

Apparently they used the thinnest Copper they could find when they built the
place.
I used a caliper on it, and found it to be 0.028, which I guess is a grade M
(outside diameter of 5/8 inch)

But, it still should take the household pressure without any problem, I
would think.
True ?

The plumber replaced it with heavier wall stuff of approx. 0.038, which is
probably
Type L

Questions:

a. What might make a pinhole leake in the middle of a clear run ?
I guess the pinhole can be considered as a corrosion type of breakthrough.

b. How common is something like this is the thinwall Type M tubing ?
What causes ?

c. 35 years ago, was this (Type M) a common Copper gage they used for
household
hot and cold water lines ?

d. Is it still allowed, or the Code prohibits it now all over ?

Any thoughts on this would be most appreciated.

Thanks,
Bob.

This happened in my parents' house. Pinhole, middle of a run, no
damage or anything. At least decades old. Luckily all the plumbing in
the house is exposed so it was easy to spot (middle of the kitchen
ceiling) and fix. (Why don't we do it like that now?

So this is a normal failure mode. Why that spot? ... a tiny inclusion
of foreign material when the pipe was made; a scratch from the
plumber's watch fob; cosmic ray. Unknowable.

I'm pretty sure M and L are both ok by most codes for residential use
in the U.S. and Canada. One pinhole in 35 years is considered
tolerable. It's up to you to ask for the better stuff if your budget
allows.

Chip C
Toronto