Introduction
Did you know that there are different types of copper pipe and tubing? Copper pipe is typically used for the potable water in your home but copper pipe is also used for wastewater, fuel, and air conditioning. Learn how to tell apart the different types of copper and which to use for your next project.
Water Copper
Copper that is used for potable water is typically made as straight pipe. This type of copper is referred to as “hard” copper as pipe is not malleable. This pipe requires fittings such as tees and elbows to change direction. Water copper is measured by the nominal inner diameter (I.D.). Typical sizes are 1/2″, 3/4″ and 1″ but hard copper pipe can be found in sizes smaller or larger. The hard copper pipes also come in “types” which refer to the wall thickness of the pipe. There are four common types, in order of larger wall thickness: Type K (green), Type L (blue), and Type M (red). Hard copper pipe most commonly found in your house will be Type L or Type M but could include Type K depending on local codes and traditions. Typically Type M is used for behind the wall and Type L for underground or exposed piping.
Fixture or Appliance Copper
Copper that is used for fixtures or appliances such as faucets or AC condensers use copper tubing that is coiled. This type of copper is also called “soft” copper as it malleable. Soft copper tubing is measured by the outer diameter (O.D.) and uses compression or flare fittings to connect to the fixture or appliance. Soft copper tubing is also measured by wall thickness, in order of larger wall thickness: Type K (green), Type L (blue), Type M (red), and Refrigeration (yellow). Typical sizes are 1/4″, 3/8″, and 1/2″ tubing but can be found in sizes smaller or larger.
DWV Copper
Copper that is used for DWV is typically made as straight hard pipe. This type of pipe requires fittings such as tees and elbows to change direction and is measured from the nominal inner diameter (I.D.). DWV copper is not typically found in newer homes but can be found in older homes or as required by local code.
Further Information
For more information such as soldering copper pipe, see our other articles.