The Pipe Primer

If you are a do-it-yourself-er, you may be confused by the varieties of pipe available on the market today. Each pipe has its own particular use, which is often is dictated by plumbing codes in your locale. Climate can also be a factor; living in a temperate zone means your needs are different than a zone that has days of below zero weather. There is also the concern about health hazards in the home. This article focuses on the types of pipes available, and their applications.

Types Available

Here is a list of plumbing pipe available today:

  • Rigid copper
  • Flexible copper
  • Rigid plastic PVC
  • ABS (acrylonitrile butadiene styrene)
  • PEX (Crosslink Polyethylene)
  • galvanized steel

Let's look at these a little closer. Each type has its own special attributes and usage.

Rigid copper has been widely used since the 60s in home construction. It is non-corrosive and lends itself to many different applications. Prior to 1988, lead was used in the soldering of connections, raising some concern about health hazards. Rigid copper is a first choice for water lines. Because it cannot be bent, it must use fittings for bends going around corners or other obstacles. It uses sweat connectors, crimp connectors and compression fittings in plumbing applications.

Soft copper tubing is sometimes used in refrigerant lines and HVAC applications. It is easily bendable to get around corners and obstacles. It can be flared for connector fittings, unlike rigid copper pipe. It is commonly used in attaching water fixtures in the kitchen and bathroom.

Rigid plastic PVC pipe is used for drainage applications. It uses elbows and tees much as rigid copper or galvanized pipe for going around corners or obstacles. White PVC cannot be used for hot water applications. PVC is extremely strong and non corrosive. It is joined using a special solvent that bonds to a water tight and durable bond. It is often used as venting for energy efficient furnaces.

ABS plastic pipe has much the same qualities of PVC. It is used in venting, waste removal and drains. It is generally black, and it has great weight bearing capabilities, even in low temperatures. The difference between the two is pressure rating, with ABS having a higher rating.

PEX piping is not without controversy. It has been used extensively in Europe for over 35 years, but in the United States many wonder about its uses in certain applications. PEX is made from high density polyethylene. Its uses are in hydronic radiant heating systems, domestic water piping and insulation for high-tension electrical cables. One of its major advantages is its flexibility, making it perfect for difficult applications. PEX is often installed using a distribution manifold which connects to the main water supply. This makes it very easy to work on specific areas of the home. For example, you could turn off the water at the distribution manifold to the kitchen sink and make repairs without shutting off the water supply to the rest of the home. If used in a hydronic radiant heating system along with ferrous materials, it must contain an oxygen barrier to avoid rusting of the ferrous materials. This is accomplished by sandwiching aluminum tubing with the PEX. It typically has five layers. PEX requires special fittings for use.

Galvanized steel pipe is generally not used in plumbing any longer. It is typically found in older homes. It isn't used a lot any more because of its tendency to clog with mineral deposits and scale, causing low water pressure. It is still sold in the standard 21-foot lengths. It is cut to length using a heavy duty tubing cutter or hacksaw, and then threaded for the application. Joints are made using pipe thread compound to insure a tight water seal. Standard fittings are available, such as tees and elbows. Galvanized pipe is now often used for railings or replacement of existing galvanized pipe in the home.

Knowing what pipe to use for any application is important. A lot of pipe uses are dependent on local building codes. It is advisable to check with local building officials and inspectors before proceeding in any application. Using the proper pipe for any typical application makes the job easier, and checking with local authorities makes the application up to code.