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"Serving South Florida since 1994"                                            Phone:  Martin: (772) 559-9881    Broward: (954) 340-6615

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Plumbing Pipe Types

In old construction, lead plumbing was common. It was generally eclipsed toward the end of the 100s by galvanized iron water pipes which were attached with threaded pipe fittings. Copper with soldered fittings became popular around 1950, though it had been used as early as 1900. Plastic supply pipes have become increasingly common since about 1980, with a variety of materials and fittings employed.

Galvanized iron supply pipes are commonly found with interior diameters from 1/2" to 2", though most domestic systems won't require any supply pipes larger than 3/4". (Note that iron is also often used in drain/waste/vent, see the section on drain pipes.) Pipes have NPT ("National Pipe Thread") standard threads, which mate with inside threads on elbows, couplers and other fittings. Galvanized iron (often known simply as "galv" or "iron" in the plumbing trade) is relatively expensive, difficult to work with (due to weight and requirement of a pipe threader), and suffers from a tendency to obstruction due to mineral deposits forming on the inside of the pipe. It remains common for repair of existing "galv" systems and to satisfy building code non-combustiblity requirements typically found in hotels, apartment buildings and other commercial applications. It is also extremely durable.

Copper tubes were introduced in about 1900, but didn't become popular until approximately 1950 (depending on local building codes). (Note that some copper and brass tubes are also used as drain/waste/vent pipes; for those applications, see the section on drainage systems.) Common classes of copper plumbing tube are "Type K", "Type L" and "Type M"; Type "M" is relatively inexpensive and relatively thin-walled and generally suitable for residential use, with a correspondingly lower water working pressure WWP, Type "L" has a thicker pipe wall section, and is more often used in commercial above-ground applications, Type "K" has the thickest wall section of the three types of pressure rated tubing and is commonly used for underground burial, with a suitable corrosion protection coating or continuous polyethylene sleeve as required by code. Types "M" and "L" are generally available in both hard drawn "sticks" and in rolls of soft annealed tubing, Type "K" is usually only available in hard drawn quantities of 20'-0" "sticks". The OD of plumbing tube is 1/" larger than the nominal diameter because early plumbing tube had a standard wall thickness of 1/16". When better metallurgy made thinner walled tube possible, the OD was preserved to avoid changing the design of fittings.

Generally, copper tubes are soldered directly into copper or brass fittings, although compression or flare fittings are commonly used by residential plumbers (Note: the annealing quality of the pipe or tube can affect the performance of compression fittings and their ability to "make-up" during installation). Formerly, concerns with copper supply tubes included the lead used in the (50%tin-50%lead) solder at joints. Some studies have shown significant "leaching" of the lead into the potable water stream, particularly after long periods of low usage, followed by peak demand periods. In hard water applications, shortly after installation, the interior of the pipes will be coated with the deposited minerals, which had been dissolved in the water and therefore the vast majority of exposed lead would be prevented from entering the potable water. Building code requirements often require lead-free solder for copper and brass. Building Codes throughout the U.S. require the use of virtually "lead-free" (<.2% lead) solder or filler metals.

Plastic pipe is in wide use for domestic water supply, waste or vent pipe, polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), polypropylene (PP) These materials must be proven by UL testing to meet or exceed the maximum flame spread rating of 25 and maximum smoke developed rating of 50 when tested in accordance with ASTM E4, also applicable UL and NFPA standard test methods. PVC/CPVC - rigid plastic pipes similar to PVC drain pipes but with thicker walls to deal with municipal water pressure, introduced around 1980. PVC should be used for cold water only, or venting, CPVC should be used for hot and cold. Connections are made with primers and solvent cements, consult pipe and fitting manufacturer for best combination.

  • PBT - flexible (usually gray or blue) plastic pipe which is attached to barbed fittings and secured in place with a copper crimp ring. The primary manufacturer of PBT tubing and fittings was driven into bankruptcy by a class-action lawsuit over failures of this system.

  • PEX - extruded high density polyethylene system with mechanically joined fittings employing barbs and crimped steel or copper fittings.

  • Polybutylene -Polybutylene is a form of plastic resin that was used extensively in the manufacture of water supply piping from 198 until 1995

  • Polytanks - Plastic polyethylene cisterns, underground water tanks, above ground water tanks, are made of linear polyethylene suitable as a potable water storage tank, provided in white, black or green, approved by NSF and made of FDA approved materials

  • Aqua - known as PEX-Al-PEX, for its PEX/aluminum sandwich - made by Ipex, aluminum pipe sandwiched between layers of PEX and connected with brass compression fittings. In 2005, a large number of their fittings were recalled.

 

 

Phone: (772) 559-9881 Phone: (954) 340-6615

E-Mail: ev@magnuminspections.com

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