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PLUMBING SYSTEM INSPECT DIAGNOSE REPAIR
AGE of PLUMBING MATERIALS & FIXTURES
AIR DISCHARGE at FAUCETS, FIXTURES
ANTI SCALD VALVES
ANODES & DIP TUBES on WATER HEATERS
BACKUP PREVENTION, SEPTIC
BACKUP PREVENTION, SEWER LINE
BACKWATER VALVES, SEWER LINE
BATH & KITCHEN DESIGN GUIDE
CHEMICAL CONTAMINANTS in WATER
CHEMICAL ODOR SOURCES
CHLORINE IN DRINKING WATER
DEBRIS in WATER SUPPLY, Water Heater
DEPTH of SEPTIC TANK
DRAIN & SEWER PIPING
FAUCETS & CONTROLS, KITCHEN & BATH
FAUCETS, OUTDOOR HOSE BIBBS
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOOR DRAIN / TRAP ODORS
FLUSHOMETER VALVES for TOILETS URINALS
GAS PIPING, VALVES, CONTROLS
GALVANIC SCALE & METAL CORROSION
HARD WATER - SOFTENERS
HEAT TAPES, Heat, Insulation prevent Freeze-Up
LEAD POISONING HAZARDS GUIDE
LEAD IN DRINKING WATER, HOW to REDUCE
METHANE GAS SOURCES
MIXING / ANTI-SCALD VALVES
MUNICIPAL WATER PRESSURE IMPROVEMENTS
NOISE / SOUND DIAGNOSIS & CURE
ODORS GASES SMELLS, DIAGNOSIS & CURE
ODORS IN WATER
ODORS, SEPTIC or SEWER
ODORS SEWER GAS in COLD WEATHER
ODORS, SULPHUR SMELL SOURCES
ANIMAL or URINE ODOR SOURCE DETECTION
PIPING IN BUILDINGS, Clogs Leaks Types
PLUMBING FIXTURES, KITCHEN, BATH
PLUMBING NOISE CONTROL
PLUMBING VENT DEFINITIONS & CODES
PLUMBING VENT DEFECTS & NOISES
PUMPS, WATER REPAIR
RELIEF VALVE LEAKS
RELIEF VALVES - TP Valves on Boilers
RELIEF VALVES - STEAM TP VALVES
RELIEF VALVES - Water Heaters
RELIEF VALVES - Water Tanks
REPAIR BURST LEAKY PIPES
METHANE GAS HAZARDS
SEPTIC SYSTEM INSPECT DIAGNOSE REPAIR
SHUTOFF VALVE LOCATION, USE
SULPHUR & SEWER GAS SMELL SOURCES
SWEATING (CONDENSATION) on PIPES, TANKS
TOILETS, INSPECT, INSTALL, REPAIR
WATER, WELLS, WATER TANKS: TESTING GUIDE
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PUMPS & TANKS
WATER SOFTENERS & CONDITIONERS
WATER SOURCE ALTERNATIVES
WATER SUPPLY & DRAIN PIPING
WATER SHUTOFF VALVE LOCATION, USE
WATER SHUTOFF VALVE, WELL PUMP
WATER TESTS, CONTAMINANTS, TREATMENT
WELLS CISTERNS & SPRINGS
WINTERIZE A BUILDING
Copper plumbing, copper supply & copper drain pipes: this article lists our in-depth articles on inspecting, testing, and repairing problems with copper plumbing: water supply and drain waste vent piping, plumbing traps, piping materials, clogged or noisy pipes, and types of pipe hazards or product defects.
The articles at this website will answer most questions about water supply & drain piping, wells, & water tanks as well as many other building plumbing system inspection or defect topics.
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Types of Copper Piping used in buildings
Our page top photograph shows a remarkable method used by a homeowner to handle leaks at a poor solder joint on copper water supply piping.
Our photograph of copper water supply piping (left) tells us that this is a cold water supply line located in a humid or wet crawl area - notice the condensation on the piping? More about "sweating" cold water pipes is at CONDENSATION or SWEATING PIPES, TANKS.
The following summary notes about copper and other types of building piping are from Carson Dunlop Associates' Home Reference Book, used with permission:
Copper piping has been used extensively since the early 1950s for supply lines from the city main to the house as well as for in-building water supply and drain piping.
Copper water supply piping is typically 1/2 or 3/4 inch diameter. Copper piping is typically 1/2 or 3/4 inch diameter. Copper piping has soldered connections and the walls of the pipe are thinner than galvanized steel. Copper piping has soldered connections and the walls of the pipe are thinner than galvanized steel.
From 1950 to 1970, 1/2-inch diameter piping was used commonly for residential building water supply pipes. After 1970, 3/4-inch diameter copper service piping has been more common for building water supply piping.
Guide to K, L, and M and Other Types of Copper Pipes used in Buildigns: life expectancy, izes, thickness, durability & uses
The life expectancy of copper piping is dependent on water conditions.
In many areas, its life expectancy is indefinite. In harsh corrosive water or corrosive soil conditions, it may fail within 20 years or even less.
Occasionally manufacturing defects also result in early failure of copper building piping. We discuss water pH, acidity and corrosiveness at Copper Piping FAQsbelow.
Carson Dunlop Associates' sketch (left) illustrates three types of copper piping used in buildings for water supply or drains. In order of thickness, from thinnest to thickest pipe walls, read Types M, L, or K copper.
How is Copper Piping Sold: lengths, diameters
Copper piping is sold in nominal or standard sizes in straight lengths of 12 ft. 18 ft. or 20 ft. from 1/4" diameter all the way up to 12-inches in diameter, depending on the copper type, thickness, grade, and intended application. Copper piping from 1/4" up to 2-inch in diameter is also sold in coils of 45' up to 100 ft. depending on the pipe diameter.
What is the Relationship Between Nominal Copper Pipe Size and its Actual Physical Size?
Copper piping discussed here and used for plumbing is 1/8" larger in diameter than its nominal diameter. So a 1/2" copper pipe will actually measure 5/8" in thickness. The actual internal diameter of a copper pipe will vary depending on the thickness of the pipe wall, even though these outside dimensions remain the same. For example, because K-copper has a thicker tube wall than Type M copper, a 1/2" K-copper pipe will have a slightly smaller inside diameter than a 1/2" L or M copper pipe.
Refrigeration Tubing Copper
Unlike copper used for plumbing (above), copper tubing used for HVACR (heating, ventilating, air conditioning & refrigeration systems), is sold in sizes that correspond to the actual outside diameter of the tubing.
The copper content of copper piping meeting the ASTM standards below is virtually pure copper - or 99.9% Cu. The copper is shiny when purchased, typically having had any exterior or interior surface oxidants cleaned off using phosphorous. If you hear reference to DHP copper or C122 coppeer, this is the product being described.
The four most-relevant standards for copper pipe thickness and dimensions depend on the intended application and use and are listed as follows:
Flexible copper tubing is usually joined to additional tubing sections or to other plumbing fittings by either compression fittings or flare fittings, depending on the application.
For example, compression fittings (photo at left, from Wikipedia) are sometimes used on copper water piping where soldering is difficult or inconvenient, but these are not used on copper gas or oil lines where flare fittings may be applied instead.
Flare fittings and compression fittings are intended for use on soft-temper copper piping and tubing. In addition to flare and compression fittings there are also other mechanical connectors that now work with soft or hard copper that do not require soldering.
Watch out: compression fittings are very convenient and easy to install on copper pipes or copper tubing, but if you fail to de-burr a freshly-cut copper pipe or tube, properly ream out the interior opening, or if you over-tighten the coupling during installation you may crack the brass or copper ring, leading to leaks at the connector.
Compression fittings are used with K-copper. K copper pipes and tubing can also be joined or connected using flare fittings and sweat fittings discussed below.
Flare fittings used on flexible copper piping and their leaks and defects are discussed at GAS LEAK DETECTION, LP / NG and GAS PIPING DEFECTS. Using a special flaring tool the soft copper tubing or piping is actually spread open or flared at its end in order to mate with the female end of the flare fitting connector shown in our photograph.
Watch out: defects in flare fittings used on flexible copper tubing can result in gas leaks out of gas piping, and in the case of oil piping such as for oil-fired heaters, flare fitting defects result in both oil leaks out of the system and air leaks into the system. Air leaks into oil piping in turn lead to improper oil burner operation and even potentially dangerous conditions. Flare fitting defects include:
Seat and flare fittings are permitted on K and L copper. LP gas tubing. These fittings are not used on refrigeration equipment.
Soft copper tubing can also be joined by using a swaging tool that expands the open end of one of the tubes to be joined so that its mate can be inseted into the enlarged opening, and the result sealed by soldering or brazing.
This is a common procedure when using air conditioning refrigerant tubing because of the high pressures that may be involved and the need for extra strong resistance to leaks in piping that may be subject to wide temperature variations as well as mechanical vibration.
Our photo (red arrow in photo at left) illustrates swaged fittings on copper tubing - you can see the swaged tubing joints at the left and right ends of the gray filter-dryer on this air conditioning high pressure refrigeration line exiting at the bottom of a compressor-condenser unit.
A swaging tool is inserted into the end of the copper tube and hammered inwards. As the properly-calibrated diameter of the swaging tool is forced into the copper tube, the copper expands to just the right size to accept the outer diameter of the mating section to be inserted. For example, if we are swage fitting two sections a 3/8" nominal diameter copper tube together, the swaging tool will enlarge the receiving copper tube section so that its inside diameter will accept the 3/8" outer diameter of the un-treaterd tube to be joined.
Usually we work the swaging process on tubing at ambient temperatures but some procedures call for pre-heating the copper to make it easier to expand.
Watch out: Soft copper tubing is drawn copper while hard tubing is annealed. It's easy to swage fit soft copper, usually. But if copper tubing has been repeatedly bent, that process may have annealed the copper somewhat, making it difficult to form either a flare fitting or a swaged fitting without cracking the tubing. Copper tubing may also become crack prone when exposed to mercaptan or other odorants in LP gas or natural gas. Moisture exposure and even some types of solder also can affect its susceptability to cracking later. For these reasons copper tubing is not allowed for natural gas distribution.
"Sweat" fittings or "soldered fittings" for copper piping refer to the traditional and perhaps most widely-used method for residential copper suppy and drain pipe connections, bends, elbows, valves, and similar fittings in buildings.
Depending on the connection required, a coupling (straight connection), 90 degree ell, 45 degree ell, tee, and even fittings that marry copper pipes of different diameters are soldered to the copper tubing or pipe to make the connection.
Sweat fittings may themselves be made of copper tubing that has been formed by machine, or from cast or milled bronze.
Watch out: on older buildings brass water supply piping may have been used, and may be at or near the end of its useful life. It can be tricky to tell the difference between brass water supply piping and copper water supply piping if you are not experienced with these materials, as their colors are similar, especially when both types of piping have become an oxidized brownish color with age.
Both brass and copper are non-magnetic, so they won't respond to a "magnet" test to look for iron or steel.
Brass water supply piping, unlike copper, is a thicker material that is usually joined by threaded fittings of the same size and pipe thread specifications (NPT) as iron and galvanized iron piping.
Usually, brass piping is also so rigid that it is not bendable. Or not very bendable anyway. So in our photograph (left) of water supply piping at a bath tub in an older home, the larger-diameter left-hand pipe is surely brass, connected to a galvanized iron fitting at its bottom end. The right-hand vertical pipe may be copper tubing as is the darker copper pipe at left behind our brass one.
Don't worry about that odd little machine in bottom center of the photo - we were collecting an air sample in this wall cavity.
Water chemistry, Electrical Grounding, Netural Wiring, & Copper Pipe Pinholing & Leaks
In a building where leaks are found recurrent in copper piping there are several possible explanations including these possible causes for the pinhole leak in copper water piping under a building concrete floor slab as well as at other locations:
Summary of the issue around grounding building water piping
Many sources, including the Connecticut DOH have pointed out a long-standing disagreement & confusion about the reasons for grouinding building water supply piping. For example
This statement is a bit of a red herring. Water and some plumbing associations are concerned about building owner complaints about metal water supply pipe corrosion and leakage that might be traced to or blamed on the electrical grounding of those systems. Wishing to avoid those complaints the industry, under the aegis of warning that water suppliers can't be responsible for the failure of such an electrical ground [a valid caveat] a warning is issued that also gives relief for metal piping leaks caused by a variety of other problems such as
More to the point, metal water piping is grounded not to provide an electrical ground for the building (we agree completely that water piping as a ground is unreliable for many reasons, (such as inclusion of non-conductive plastic piping, diaelectric fittings, water meters, etc). Metal water piping is bonded to a building ground system as an important safety precaution to protect building occupants from electrocution hazards should live electrical wires or components come in contact with buidling piping, faucets, fixtures, etc.
In a properly-wired building, the grounding conductor and bonding system do not normally carry current, and would not be blamed for copper pipe pinholing etc. The grounding system is intended to conduct electrical current only in the event of a fault or emergency [such as a lightning strike or a hair dryer dropped into the bath tub or sink].
Details about the code requirements and reasons for grounding metal water piping are at WATER PIPING GROUND BOND
How to Check for Electrical System Problems that Corrode Copper Water Pipes
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Frequently Asked Questions (FAQs)
Question: Acidic water & copper pipe corrosion/leak risks
I get a lot of blue stains on bathtubs and sinks, which I assume is copper leached from the inside of the copper water-supply piping. I built the house about 16 years ago and replaced the water heater a few years ago.
Am I at risk of developing pin holes or other damage to the copper plumbing and other equipment, including an electric water heater, boiler, and baseboard radiation?
If that’s the case, what’s the preferred (and cheapest) solution: calcite neutralizer tank, soda ash feeder, or other?
FYI, copper level was last measured at 0.11 mg/L, well below the MCL of 1.3, so I don’t think there’s a health issue. But I figure if copper gets leached from the pipes for enough years, at some point there won’t be much pipe left.
Muchas gracias, Steven Bliss, 4 Burlington, VT
This topic has been moved to its own article now found at CORROSIVITY or ACIDITY of WATER
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Technical Reviewers & References
Other water supply and drain piping and water pressure articles: