Anymore, when I think of someone plumbing with copper, I think of the rich. As an aside, copper is so expensive now that a whole new copper system may be reaching the point of being too costly. (Enter: PEX.)

But, your questions are about copper (and brass and bronze) which in another era were plentiful and affordable. The rules made then are still good rules, but might not be made in this age. In any case, the significant part is that copper typing is similar to the Schedule numbers in other piping  that is, it speaks to wall thickness, temper and appropriate applications.

Type K is the heaviest, in the consumer market, and is required for underground installation. L and M are successively thinner; both are used for residential and commercial systems.

This is to say that they are both adequate  however the use may be regulated by local codes. As such, you are most like the find the type L, which will satisfy both demands.

Your question seems to be that the fittings should match, too. The same logic is applied there. As a practical fact, you may be only able to buy L in the Big Box Stores, which is a cost compromise. Similarly, cast and sintered fittings are not required and sold in the consumer market as it was once.

All of this is to assuage the fears you indicate as the subject of your posting. In reality, most of us only need to know this much: use K for underground work. Nothing to this plumbing stuff. (Kidding.)

Pinoke

GREAT QUESTION and one I am sure is of interest to all.

In the plumbing, pipe fitting and HVAC industries originaly the only pipe available was iron pipe. When comparing the volume of pipe sizes we must use a formula that considers the cross sectional area rather than the diameter thus each increase in pipe size approximately doubles the volume. The actual formula for comparison is:

Large Diameter Squared divided by the Small Diameter Squared . Example

3/4" compared to 1/2" = (.75x.75)/(.5x.5) = .5625/.25= 2.25

From this we can see that a 3/4" pipe has 2.25 times the volume of a 1/2" pipe.

Another basic rule of thumb, if you double the diameter you increase the volume by four times.

Understanding that all pipe layout formulas were originally developed for iron pipe it then stands that as new materials became available they were manufactured in sizes that approximated their iron pipe equivalent thus we see copper, PVC, or CPVC listed in "Nominal" sizes. This means a 1/2" nominal copper pipe will be slightly different in size but for all intents and purposes it would meet the volume requirements of a 1/2" iron pipe thus we see the other piping materials listed in the same size variations as iron pipe.

While we common think of the word "Schedule" as meaning a time table of events, properly the word Schedule means "A table" thus in the piping specifications each size of pipe is listed in a table of specifications and the number or letter indicates which table applies to the product in question thus we see iron pipe,PVC or CPVC pipe listed as Sched. 20, Sched.40, sched.80 etc.

Rather than use the schedule numbers copper pipe is defined by a Letter indicating which table of specifictions apply. While the specifications are listed alphabetically Copper pipe is classified as Heavy Wall, Standard or Medium Wall, and Light wall. It was merely by co-incidence that copper pipe designations seem to be backwards:

Example 1/2" Nominal Copper Pipe:
TYPE k - Heavy Wall OD 0.625 ID 0.527 Wall thicknes .049
TYPE L - Medium Wall 0.625 0.545 .040
TYPE M - Light Wall. 0.625 0.569 .028

As you can see, even though the Type K heavy wall pipe has the thickest wall the ID of the pipe still remains slightly larger than its fractional designation but for the purposes of standardization all three types have the same OD so the fittings are interchangeable.

Copper pipe is manufactured in two varieties.

The 10ft long lengths of rigid copper pipe that we are most familiar with is properly called "Hard Drawn Copper Pipe".

They also make 60' or 100' rolls of "Annealed Copper Pipe" and we must be very careful not to confuse Annealed Copper role pipe with Copper tubing which is made to an entirely different sizing standard. (Copper tubing is made to the ASTM-CTS standard--CTS =Copper Tubing Standard).

FYI-While CPVC is manufactured to Pipe Standards the CPVC pipe that we commonly see in the hardware stores is also made to the CTS standard rather than Pipe standards.

Primarily copper fittings are made in the hard drawn copper standard however there are copper fittings such as you describe which appear to have been cast rather than drawn or formed from copper pipe. These fittings are properly called "Wrought Copper fittings."

Under the Uniform Plumbing Code (UPC) whenever copper pipe is run under a slab within the confines of a structure we must use wrought copper fittings and all joints must be brazed rather than soldered.

Under both the International Residential Code and the Uniform Plumbing Code all three types of copper, K,L & M may be used for both Supply (the water line from a well or municipal main to the structure) and Distribution (Lines within a structure.) however the IRC only permits type M inside a structure if it is above ground.

Type K-Heavy wall copper pipe can be obtained through most home supplies or hardware stores by special order or you can but it from a Plumbing or Heating Supply house but as a rule it is only used for applications that involve pressures or temperatures that exceed the allowable limits in general plumbing use. We commonly use type K roll pipe for direct burial supply lines but the use of type K in general plumbing within a structure would be considered serious overkill.

While type L (med.wall) copper is considered the industry standard today in years past type M (thin wall) was considered the standard for residential service and type L was primarily used in commercial applications thus the overwhelming majority of residential structures that have copper pipe have type M thinwall pipe and even that has proven to provide 50+ yrs of service when properly sized and installed correctly.

It is true that under some rare conditions copper pipe does exhibit wear in the form of pin holes, but in the final analysis it can also be said that those problems are directly attributed to water quality or in many cases improperly sized pipe which resulted in excessive velocity of flow. Copper pipe will exhibit internal wall erosion if the velocity of flow exceeds 10feet per second and it is for that reason that the codes now define a Fixture Unit method of determining proper pipe size.

In regards to water quality. If you live in a region that has water quality issues that are detrimental to copper pipe, I must then wonder what those issues are doing to your general health as well. In my personal opinion rather than worry about finding a pipe that will tolerate those problems I think the homeowner and his or her family would be much better served to consider installing a water treatment system to correct the problem.

Absolutely. Copper pipe is still probably the most proven of plumbing materials for water delivery, I don't know how far back it goes but I'd venture under good conditions, it'd be good for 100+ years. Pex in that regard is unproven, I remember "alkathene," a plastic that enjoyed a brief popularity in New Zealand in the '70's, but I doubt it's used for anything but agricultural purposes now. On the other hand, I have no desire to return to lead or copper for drainage, PVC and ABS seem to do a pretty good job for drains (but not suitable for potable or hot water) I think the big issue with plastics is they age and their characteristics change over time, perhaps unpredictably. Of course metals corrode and fatigue as well.

True, "aggressive" water can corrode copper pipe and you can end up with the characteristic green staining copper salts indicate, and in those circumstances copper isn't good for you, but with good quality water, for all purposes, copper's inert.

I agree that treating the water's the priority.

What does treating the water actually mean. For those of us with a well, what should one do. I guess testing is first in order, but what test? Are we talking hard soft water tests? Are small mineral particles in the water what causes errosion? Does one need a whole house filter? My neighbor has a whole house filter, and that can get expensive changing them.

Seems like there is not confirmed reason for pipe failures? This one may be a good subject for the Myth Busters??

Pete P...

People who have home wells should have their water tested periodically. Contact your county board of health and they can give you the information on how to contact a local independant testing lab where you can get your water tested.

All municipal water suppliers are required to have inhouse testing facilities where they continually perform tests on the water they are delivering through the municipal water system. Many of those inhouse labs will also perform complete water quality tests for home wells for a small testing fee.

Generally the water tests are very reasonable, about $25 to $35.

In our work place we have a fireline on the ground level.It got damaged by a fork lift and stated to leak.we try to fix it with rubber and hose clips but it did not work and finaly we cemented.
can it be consideered as a permanant repair?
As a permanant repaire could we cut the joint apart and insert with a PVC pipe as per PVC pipe fitting procedure
Please advise