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View Full Version : Copper Pipe... NOT 1/2", But Close??



Scott Hildenbrand
11-25-2009, 8:12 PM
Ok... So I had some copper pipe to rupture last winter during the ice storm.. I figured I'd slap a quick fix onto it and just use a hose since I was going to replace it later anyway... Well the hose slipped off so I thought I'd go ahead and fix it semi right..

Since it's CPVC feeding a copper line I just picked up a CPVC to 1/2" compression fitting.. No brainer, right?

Well the 1/2" CPVC was surely half inch... But the copper pipe was not... It actually measures 83/128ths... or .65 inches... or 16.55mm... How ever you want it.

Now... The guy at Lowes said that copper can swell as it ages, which caused me to raise an eyebrow... I'd already cut WELL back from the burst so I know it's not that..

At any rate, I used one of those rubber on both end couplers to patch it up until I can replace all the line...

So what the heck is it though.. Is it old line that really did swell, or some non standard size? Awful close to 5/8th...

Inner diameter measures 37/64th behind the burr from cutting it. So... The inner diameter is lager than 1/2"...

Rather confusing.

Mike Cutler
11-25-2009, 8:43 PM
Scott

Not knowing exactly what you purchased as a transition adapter, I'm guessing it's a "tubing" adapter.
Tubing is measured to the OD. Pipe to the ID, however within a given schedule, or ASTM rating the wall thickness can vary, so you just can't just simply measure the ID and be done with it.

I'm sure that in some theoretical argument, copper can be proven to swell. In real life applications, it's pretty stable.

Scott Hildenbrand
11-25-2009, 8:51 PM
Y'all are missing the point.. The OD is 83/128th the whole length of the pipe... WELL past the rupture...

I know copper swells when it freezes.

I also measured a scrap piece that was laying there since WELL before it ruptured (several years) and it was also 83/128ths.

My point about the ID is that it's thick pipe.. Twice as thick as modern and not easily bent.

Jamie Buxton
11-25-2009, 9:37 PM
Type L copper pipe that's called 5/8 has a typical inside diameter of .667". That's close to what you're measuring. Type L is what's commonly used in residential construction. There's also Type K copper pipe. It has a thicker wall than Type L. It uses the same fittings as Type L, so the OD has to be the same. That is, the ID is a little smaller than Type L. I don't have the ID at hand, but Type K might well be what you have.

Tom Veatch
11-26-2009, 11:20 AM
ASTM B88 dimensions for copper rigid pipe (drawn) and flexible tube (annealed) (http://www.engineeringtoolbox.com/astm-copper-tubes-d_779.html), Types K, L, and M.

Dave Beauchesne
11-27-2009, 11:43 PM
Scott:

I am a refrigeration mechanic ( have been for 30 years ) -

HVAC Guys use the real OD of copper L tubing - like my instructor said 30 years ago, if you take a piece of plumbers 1/2 '' copper tube, you WILL NOT find the dimension of 1/2 '' ( .500 '' ) anywhere on the tube.

So, plumbing copper tubing ( pipe ) that is 1/2'', 3/4'' and 1'' is actually
5/8'' ( .625 '' ) , 7/8'' ( .825'' ) and 1 1/8'' ( 1.125 '' ) OD respectively. I ( as a refrigeration guy ) call it 5/8, 7/8 and 1 1/8 - the real OD. Part of the confusion is that copper tubing is just that - tubing - while pipe is threaded ( and a 1/2 '' black iron pipe is close to 1/2 '' ID ) but is about 7/8 '' OD ( approximately ) - confusing - I know.

The Lowes guy must have visited B.C. and picked up some of our green herb; copper is as stable as it comes ( unless frozen when full of water ) - I have dealt with literally hundreds of miles of the stuff in my trade - copper that has been in service, under pressures every day for 30 years of 250 psi ++ - stable.

That being said, I have seen several times where tubing has been ' stretched ' via freezing water; to a point where fittings will no longer fit. My suggestion is that if you have copper pipe that has been ' stretched ' it should be replaced - it can split as it has been stretched and weakened.

Refrigeration grade tube is seamless as is better grades of plumbing tubing; I have seen substandard and offshore tubing that is has a seam and is less than ideal.

Hope this helps -

Dave Beauchesne

Ken Garlock
11-28-2009, 12:21 PM
Way back some 50 years ago, my father taught me that STEEL pipe is measured by the diameter of the outside, while COPPER tubing is measured by the diameter of the inside. Hence your 83/128 is close to 5/8 which in turn is the outside diameter of 1/2" copper tubing.

Run with it.:)

Scott Hildenbrand
11-28-2009, 1:31 PM
You're right, but I'd be running alot faster if 1/2" fittings would fit onto it..

It's patched for now, so it's fine.. I'll be gutting that bathroom down later anyway, all the way to the joists... So I'll have ample room to run new.

Dick Strauss
12-01-2009, 8:58 PM
1/2" fittings will work if you have the right fittings for the right schedule of copper.