[SEL] OT-OT- air lines in shop?

[P. Johns]

A couple of quick notes:

The wall thickness of the copper won't matter, L has a thicker wall than M.
That makes for a minor difference in flow quantity)

Copper "pipe" is called that by the plumbing industry, it is 'tubing'
according to the manufacturer. When you by compression fittings for 'pipe',
the 1/2" pipe uses 5/8 fittings, the 3/4 uses 7/8. Pipe is a nominal size,
tubing is actual outside dimension. So you get solder fittings in pipe
sizes, compression fittings in tube sizes.

1/2 pipe (of any type) will move a lot of air, probably enough for any air
tool commonly used; remember it is under high pressure - usually two times
or more than normal water pressure. I have used 1/2 galvanized - years ago -
and had plenty of volume for an auto shop; copper will deliver more.

I have use both iron and copper for shop lines, but that was before this
modern poly plastic stuff was availabe and I don't see why something like
Pex wouldn't work EXCEPT for oil in the line at, or near, the
compressor.That may be dealt with by a sediment, or moisture trap. You
shouldn''t need a log drip leg, as the length won't make what falls into it
(moisture) any heavier. I always used a needle valve at the bottom of the
leg and sometimes left it open slightly while running.

I have seen plastic pipe used, but I'd be afraid of it shattering from some
accident. I don't think (but don't know for sure) that it will burst from
any reasonable pressure. I just don't like the chance of physical damage
from some accident. Others would be better informed as far as safety goes -
and inconvenience as was mentioned.

Perhaps, in you situation, you could leave the compressor with copper (or
galvanized) and then run cheaper and easier to use plastic along the
ceiling, then come down with copper again.

Slope the overhead downward, toward the end of the run, so it will drain
moisture easily; 1/8" to 1/4" per foot should work fine.

That's all I can think of for now - if there are any questions, just ask.

Paul in California

PS: My training in Plumbing Engineering was back when we uased pencils and
paper for calculations, so I never paid much attention to plastic pipe.
PPS: Nice shop