Pipe manufacturers produce soft and hard soft copper pipes for plumbing purposes. Copper pipes are mainly used for supplying water.
A pipe made of soft copper tends to bend easily even without using any tool. As such, pipes made of copper are also known as tubing.
Pipes made of the hard type of copper are inflexible and require bending using special tools. Hard copper pipes are cut and joined to make a joint rather than bending them.
Most water supply lines in residential properties are made of hard type L and type M copper pipes.
Types of Copper Pipes
Copper pipe manufacturers offer four standards of copper pipe which are types L, M, DWV, and K. These letters partially indicate the relative pipe wall thickness. A pipe’s wall thickness is dependent on the pipe size.
These letter codes are also used in relating the color printed on a pipe to the type it represents. The color assists in identifying the type of copper pipe.
Green represents type K, blue represents type L, red represents type M, and yellow represents type DWV. Thus, type L copper pipes are also known as blue and type M copper pipes are also known as red.
What are the uses of different types of copper pipes?
Each type of copper pipe has a suitable application. However, DWV pipes are not ideal for application as supply lines for water because they don’t have a pressure rating.
Green copper pipes, that is type K, are the only type suitable for burying underground. They’re generally used for supplying water into a house.
Types L and M are the ideal pipes for supplying water throughout a home. Type L comes with thicker walls than type M. Type L also has a high rating in terms of pressure than type M.
Some local plumbing codes only allow the use of type L and don’t allow the use of type M in homes. However, international codes of construction allow the use of types L, M, and K pipes for supplying water.
The Differences between Types L and M
The key difference between types L and M is their pressure rating and wall thickness. The most common copper pipe sizes are ½ and ¾ inches.
Type M ½ inch measures 0.028” in wall thickness whereas type L ½ inch measures 0.04” in wall thickness. Type M ¾ inch measures 0.032” in wall thickness while type L ¾ measures 0.045”.
Generally, type L is costlier than M. The reason behind the cost difference is that type L has thicker walls, thereby weighs more.
Consequently, it requires more amount of copper to manufacture, making its cost of production higher than that of type M. Its cost of transportation is also higher due to weighing more than type M.
Copper pipes that are of similar size and type come with the same exterior diameter, making them ideal for use with the same fitting when making plumbing connections.
The interior diameter varies depending on the type as a result of the varying wall thicknesses. For instance type M ½ inch measures 0.569” while type L ½ inch measures 0.545” in diameter.
Residential Suitability of Type L and M
Copper pipes for water supply within a home are either type L or type M, unless specified otherwise by local codes. Both types have good ratings in terms of the water pressure required in municipal supply lines.
Type K, being costlier than type L, makes it less ideal for burying in the ground for water supply into a house.
The difference in cost between type L and M is enough to make most property owners prefer type M rather than type L when working on large projects.
Nevertheless, always check with your local municipal for permits before doing any plumbing project or buying construction materials.