I am a bit puzzled by copper pipe thicknesses. I know there are type M, type L and type K.

I have always thought soft copper tubing is type L.

Here is a picture of some copper tubings I have. The left and middle ones are type L 3/4" hard copper pipes. The one to the right is a section of soft copper tubing. It is obviously thicker.



I double checked the hard pipes again, and yes they have blue markings on the outside and a mild imprint "TYPE L".

How can that be?

I also checked the edges of the pipes, yes they have been cut with a tubing cutter, but I deburred them already, so it's not the edges that's been "flared" by a tubing cutter to appear thicker.

Alot of water services into the home are soft K.

So there are soft tubing type K? I didn't know that, so what I have may be type K?

For plumbing:
Green markings = type K thickest
Blue = type L thinner wall
Red = type M thinnest (only comes in hard)



Edited 1 times.

vic, don't forget yellow.
DWV type for drains.
this is the thinnest.

Thanks Packy

Vic
Are the rigid pipes stronger type of copper than the malleolable copper??

The soft copper should stand "expansion" from freezing a bit better than the rigid tubing.

I have seen soft copper pipes that have frozen and although they didn't burst, they blew up like a balloon.

They can be a problem if you try to put fittings on them without first resizing them to specifications.

Around here, the soft K copper is can be bent like tubing and is used mostly for underground water service from the main into the residence. Type L is required for all domestic water, and M is allowed on baseboard heating where the pressure is boiler controlled at around 15 psi.

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Not a plumber by trade but a fierce DIYer