Under most codes you can bend soft copper but not hard.

Type M pipe is not available untempered.
To get a soft copper pipe for bending youhave to go to type L.
More $$, and the smaller ID tends to negate some of the advanate of less joint restriction.
Add to that the relatively tight spaces allocated to plumbing in modern houses and it becomes a real PITA.

What labelling designates type L as "soft" or "untempered"? What is the magic word or letter? Is it still in blue ink? Do sizes like 1/2" and 3/4" come COILED? Straight?

With all these side-mounted T&P valves on WHs nowadays, some flexible 3/4" copper would be a slick way to plumb them... big 'ol spiral down and 'round the back and out the wall...

K,L, and M tell you about the wall thickness, as ÂSchedule does for other pipes.

ÂSoft copper is not pipe, but Âtubing. As such, the controlled dimension is the O.D., so 5/8" tubing is the same diameter as ½" piping.

When attaching a pipe downward from a water heater T&P valve, you can fit it with a ¾" IPS threaded pipe or assembly.

Pinoke

Bump... need to know the specifics about 1/2" and 3/4" bendable copper tubing... s'pose I could call my local supplier, but they're closed on Sundays... ;')

Continuous rolled copper is made to both PIPE & Tubing standards.

If the roll is labelled "COPPER PIPE" it will be measured by inside diameter and have the same dimensional standards as rigid copper pipe and will meet the same code standard for installation.

If the roll is labelled "Copper Tubing" it will be sized by its OD (outside diameter) and may only be used in plumbing as an end connector from a stop valve to a fixture.

You can but type K & L as tempered or untempered and either is aceptable for potable water use.
Yype M is the thinnest wall and is not available untempered.

Refrigeration tubing is sized by the OD, water pipe by the nominal ID.
Every plumbing house will have L in normal water sizes of 1/2 and 3/4 (nominal).
Untempered type K was routinely used for service lines from meter to house for many years before the plastics became accepted.
The untempered pipe comes in coils. Tempered pipe comes in straight lengths of 20 feet, often cut down to 10 feet.

LazyPup,
I learn something new every day. Well, new to me. I never heard of coiled pipe. But I donÂt see how it differs.

I mean, say, I have 5/8" coiled tubing and 1/2" coiled piping. How are they different? And in what conditions would a fitter would use to select a choice?

Pinoke

Roll copper pipe is made to the same ASTM ID & OD specifications as rigid tempered copper pipe. It is specified by ID size thus a 1/2" roll copper pipe would have an ID of 1/2" and an OD of 5/8". Roll copper pipe may be used interchangeably with rigid copper pipe and as Brickeye has already pointed out it is commonly used for direct burial water supply lines or used under slab to minimize joints.

There is another variation of copper pipe that undergoes a bit more quality control testing and is labelled as suitable for "Gas Lines". On copper tubing specifically labelled as "Suitable for Gas" may be used to run a gas line or gas connector, and only if the gas is certified by the supplier to contain equal to or less than 0.3grains of hydrogen sulfide per 100cu.ft of gas. (Requires a letter of certification from the gas supplier at the time of inspection).

Copper Tubing is made to the ASTM -CTS standard (Copper tubing standard). Copper tubing has a slightly thinner wall than copper pipe and copper tubing is specified by its OD. Thus a 1/2" copper tubing will have a 1/2" OD. Copper tubing may only be used as a fixture end use connector and may only be connected between the Line Stop valve and the fixture. (The compression fittings on line stop and angle stop valves is sized for copper tubing).

Refrigeration Copper tubing is made to the same ASTM -CTS specifications but it is certified moisture free and it usually has rubber plugs on both ends of the roll and a slight pressure charge of nitrogen in the pipe during shipping to insure it will remain moisture free.

Thanks, man. ThatÂs some great information. I have never realized there was a such thing as piping on the roll. I gather, from your description, that the chief difference between samples of ½" roll piping and 5/8" roll tubing is in the wall thickness.

What surprises me is that, you say, tubing is only suitable from the stop to the fixture. I would never have accepted that from a lesser writer than LP. In fact, as a practical matter, I have never seen copper tubing fail, regardless of its location or use.

A year ago, I replumbed part of a house on a slab, which had already once been replumbed with soft copper. I assumed I was looking at tubing. But it would have been roll piping.

This is one reason that a master plumber is truly a master of the trade, and the tradesmen are skilled. But, with so many lay people operating in the industry, I would hope that there was a safeguard against inadvertently misusing such similar materials.

For example, in electrical, the shape and size of a plug would mate to the receptacle of the same power rating. And #12 (20-A) wire will not fit in the backstabs of a 15-A device. I wonder, how critical is the difference in the plumbing materials, when used above ground?

Pinoke

I create blown glass art using 3/4" rigid (type M) copper pipe. I would like to create larger art pieces by bending copper and attaching my blown pieces to it. Is it possible to attach 3/4" rigid copper pipe and fittings to 7/8" soft copper tubing? Do you think the soft copper will stand up over time if used as a trellis or arbor? Thanks

Barb,

There is a slight difference in wall thickness between copper pipe and copper tubing which may effect the overall life of the products you are producing, but in my estimation that difference is so slight so as to go unnoticed for perhaps 10 years or so in your application.

FYI- As you have already discovered copper pipe is sized by its inside diameter while copper tubing is sized by its outside diameter therefore when changing from 1/2" rigid copper pipe to copper tubing you must use 5/8" tubing, and for 3/4" pipe you must use 7/8" tubing. What you may not be aware of is that copper pipe is made in both tempered rigid sticks and continuous roll. Both rigid and continuous roll copper pipe have exactly the same dimensions and wall thicknesses, therefore rather than using copper tubing or your bends you could buy roll copper "Pipe" and have exactly the same dimension.

Rigid copper pipe can also be bent using an electricians EMT bender.

Thanks for this info. Is the continuous roll copper pipe the same as annealed tempered copper? If so, is it less strong than tubing? My plan is to use rigid copper for the upright posts and major supports but I would also like to "decorate" the curved top portions with blown glass. I am worried about how much weight the annealed copper could hold. Also bending rigid copper with an EMT bender would cause dents wouldn't it?

Thanks again!

Annealed means un-tempered or soft.
Tempered is hardened.
Tempered will not bend very easily and will usually collapse and kink.
You will have to judge the weight, but type K copper is very thick walled.

I will respond to the original question first.Being a plumber for many years I can think of tons of reasons why fittings are better then bending tube although there are situations where bending is better.The biggest reason we dont bend copper is becouse the wall is not designed to take the turbulance of the water under pressure as it takes the turn and the simple act of bending the copper weakens it even more.But from an installation point of view it can be a nightmare.Routing a single piece of copper 50 feet long through a building without a mistake is a challenging task.And when it comes to tubing a mistake is a wasted roll of copper and you have to start all over again.We use soft copper for other services wich arent so aggressive such as gas,air,vaccuum.They arent as abusive as water and are usually of a much smaller size and that makes the installation easier.For example a 3/8 gas line is much easier to bend and snake through walls then say a 3/4" or 1' water line.And the service is very low pressure with no weight or turbulant properties that couse friction at turns.

"...turbulance of the water under pressure as it takes the turn..."

And the fitting turbulance is far worse than anything bending the pipe can produce.
Most of the time all I see is type M copper since it is thin wall and cheap.
Type L is very handy at snaking through existing walls to replace galvanized that has failed.
PEX would be even better, but I am still worried about the damage that can occur during fishing from nails and other sharp items in the wall (and unseen).
The strength is a non-starter. The pressure loads in refrigeration and gas (oxygen, nitrogen, etc) sevice are way over anything seen in water lines (requriing brazing on all sizes above 3/8 inch) and type M is actually not suitable.

Since coiled copper pipe is not tempered and straight pipe is tempered, is there a difference in performance? That is, strength, ability to make strong connections, etc.?

I am thinking of replacing a 2-3 foot section made with rigid 1/2 inch copper pipe with coiled copper pipe so that I can bend around obstructions and solder the two ends. (although connection at one end may be a compression type). Any tips in how to bend the pipe, other than very slowly? I assume connection procedures are the same as with rigid pipe? This is for a hot water line.
Thanks.

Hmm I'm glad I read this, but disappointed that I probably can't bend my cold supply like I wanted to...I've got a whole-house water filter to install, and to do so I'll have to bring the pipe down from the side of the floor joist to allow clearance for the filter then bring it back up. I had planned to cut the pipe, and use my benders to make a dogleg in it - so it goes down, level then back up again (and the loss of material in the bending etc isn't a problem because I have to cut the middle of the pipe out anyway)

So assuming the stuff in my house (in BC) is tempered, I won't have this as an option....although I'm led to ask, what happens when you use heat to bend it? Will heat affect the temper adversely, and at what sort of temperatures? Presumably some considerable way above normal soldering temps, I guess.

When using the bender previously (in Australia) I've noted some stippling of the surface of the outer part of the bend - I suppose precursors to cracking, but if you heat the pipe, you don't get this marking.

As for rolls of copper pipe, I've seen plenty - often used for gas line etc.

As Sircuts@freeshell.org has already pointed out, I too can think of dozens of reasons why bending copper pipe is not a good solution.

It has been mentioned that the inner wall friction of a bend is less than a fitting, which is true of factory made long radius bends where the pipe is bent in specially designed jigs prior to the tempering process but such is not the case when field bending copper.

First of all it should be thoroughly understood that no bend in copper pipe should have a radius less than 10 times the pipe diameter. (Many local codes limit bends to a minimum radius of 20 x pipe diameter).

When pipe is bent in the field two conditions happen that ultimately weaken the pipe. On the inside of the radius the pipe is compressed resulting in crosswise ridges similar to those on a corrugated pipe. (I appologize in advance if my description offends anyones sensibilities) When a pipe is field bent the outer curve of the radius is stretched leaving microscopic stretch marks similar to those seen on a womans stomach after a tough pregnancy. This also results in seriously weaking the pipe wall. We are then confronted with an increase in turbulance from the inner ridges reacting against the weakened outer wall and the end result is premature pipe wall erosion thus while a factory formed long radius bend will reduce line friction a field bend actually has much more friction problems than what would be seen with a fitting.

While bending pipe may appear like a simple task ask any electrician who runs EMT and they will tell you first hand that bending pipe is not nearly as easy as it might look. There is a small loss of linear footage when forming a bend and when making back to back bends on the same piece of pipe it can be rather tricky to compute the necessary lenths to compensate.

Obviously the interest expressed in bending copper pipe is a result of the reluctance on the part of homeowners or DIY'ers to solder but I am sure that Sircuts and Brickeye will agree with me that in the hands of an experienced plumber soldering joints can be made much quicker than figuring out the layout of bending pipe for a tight application. In fact, with a bit of practice you will find that soldering is easy and nearly as fast as fitting and glueing CPVC or PVC pipe.

To answer Shw001's question, if you are working in a really tight location it is doubtful that you will have the necessary clearances to get the minimal radius for your bends. Although I would certainly explore all the other options first, understanding that you only need a short two foot section you might find it much easier to use a corrugated copper flexible water heater connector to go around the obstruction however this should only be done providing the work will be in a non-concealed location.

Lazypup's suggestion to use a corrugated copper flexible water heater connector sounds like a great idea, but I did plan to close in the area, although I am tempted to leave an access panel.

Do the rules about bending also apply to coiled copper pipe? Or, would the pipe already be compromised because of the coiling process? (that is, wouldn't the coiled pipe already have the stretch marks on the outside of the bend and compression ridges on the inside)? After all, the pipe is already bent. ??

The bends I plan to make would be an offset of about an inch over a 1-3 foot section. Would it be OK to use the coiled copper pipe?

As mentioned above, coiled copper pipe is ok because it's not tempered, there are codes marked on non-coiled pipe so you can tell the grade and whether it can be bent....so you CAN use the coiled stuff with no ill effects, but take note, you have to be very careful and keep a broad radius (I didn't know there was a ratio/formula, but it makes sense, when putting bends in coaxial video cable there are similar rules)

When my stuff from Australia comes out of customs, I'll have two pipe bending gizmos at my disposal, one for 1/2" and one for 3/4". If you have to bend, these things, with a curved, grooved die and an arm that pulls down over it and does the bending, are the way to go. I made lots of bends in the plumbing work I did in Oz, I must admit, yeah, less joins are attractive but I hadn't considered the weakening issue - although with these jigs you don't get the folds or corrogations at all. When I was practicing with them I found I could make a beautiful 180 degree bend with no ill effects. Not sure what the water pressure was in Sydney, but it's higher than what I've noticed here in BC.

Of course, if the rules forbid pipe bending (although the supply to my hw heater has a curve in it) then one oughtn't do it, also, I always pre-heated the pipe before I did it and found I got a better bend.....I know cosmetics aren't where it's at, but I like the look of a bent pipe, and I'm fussy enough to want to do a whole section with bends and no joints until I actually come to a fixture....but that's just me ;)

I don't have a problem with soldering, so I'll just do whatever's best.