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All About Pipe
Polyvinyl Chloride (PVC)

PVC pipe has clearly become the material of choice in residential DWV applications.

PVC has excellent chemical resistance; good impact strength and crush resistance. It is resistant to fire (self-extinguishing). It's functional up to a temp. of 120° F in pressure systems and to 180° F in drain, waste and vent (DWV) applications.

Schedule 40 and 80 is often used in pressure supply and drainage systems to carry water for uses such as golf-course sprinklers and agricultural irrigation, and in underground gas-distribution systems, industrial and chemical piping, corrosive fume ducting and crude-oil transportation.

PVC will not rust, pit or degrade when exposed to moisture and is extremely resistant to a broad range of corrosive agents.

This rigid pipe is available with pressure ratings of 50 to 315 psi. For pressure lines, PVC should be used for cold-water only. It is sometimes used for household cold water pipes when copper is impractical.

PVC comes in 10 or 20-foot lengths and common diameters; and it is joined with solvent cement. It is generally more resistant to crushing or puncturing than PE pipe, and it will stand slightly higher temperatures.

For DWV applications, several types are available.

• Schedule 40 is dual use pipe.
  While it is rated for pressure, its most common use is for drainage where a more durable pipe is preferred.
  
  
• Foamcore
  has a soft-center, is a similar gauge but is more economical, lighter weight, and is suitable for drainage only. It's very popular for residential drainage installations.
  
  Foamcore (Cellular core construction) involves the simultaneous extrusion of at least three layers of material into the pipe wall: a solid outer layer, a cellular core intermediate layer, and a solid inner layer.
  
  
• ASTM 3034
  This pipe is thin-walled, and rated for drainage or conduit only, where it is shielded from impact.
  
  

PVC can be used under ground or above ground in buildings. It can also be used outdoors if the pipe contains UV inhibitors and it is painted with a water-based latex paint. PVC materials are resistant to many ordinary chemicals such as acids, bases, salts and oxidants.

Because PVC piping system components can be manufactured in a variety of colors, identification of application is easy. A common color scheme (although not universal) is:

• White for DWV
  
• White, blue, and dark gray for cold water piping
  
• Green for sewer service
  
• Dark gray for industrial pressure applications
  

This color scheme has an exception in that much of the white PVC pipe is dual rated for DWV and pressure applications.

PVC piping systems should not be used to store and/or convey compressed air or other gases.

ASTM standards mandate that PVC pipe be labeled as follows:
The manufacturer's trademark, ASTM standard, size, material designation, pressure rating (if for pressure), Schedule number, and if the pipe is for potable water, a laboratory seal or mark attesting to suitability for potable water.

PVC pipe is called solvent-weld pipe because it is most commonly joined with fittings glued together with solvent cement.

PVC can be cut with a hacksaw or cutoff saw, or with a heavy-duty tube cutter. When connecting to metal pipe, threaded fittings may be used, but generally these fittings are glued to the pipe and the pipe itself is not threaded, except for schedule 80.

Larger diameter pipe is connected with gasketed connections; this type is primarily used in underground drains. PVC is also used for ground drainage and is sold with or without perforations.

See Also:

Other:
    ASTM Reference Library (material and manufacturing specifications)

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