Copper Tube ASTM Best Price Price Chart
Copper Tube Type K, Type L and Type M copper pipe comparison:
Use Type M for most home situations. Use heavier duty, Copper Pipe Type L, for the underground and other special situations work. Type L copper pipe is recommended where you need strength and protection. But for normal “in the wall” household plumbing, Type M copper pipe is just fine.
To differentiate Copper Tube Type K, L, and M
The letter codes engraved or stick onto the pipes and differentiated by color of the printing. It's usually placed on the side of the pipe, which helps to identify which tube is classified under what type. Type K is green, type L is blue, type M is red and DWV is yellow. Type L pipe is commonly referred to as Blue Copper Pipe, whereas Type M is often referred to as Red.
Type K: Green
Type K, or green copper pipe is the only one suitable for burial and is often used to bring the water supply into a home.
Type L: Blue
Types M and L make up the water supply pipes in homes. Type L has thicker walls and a higher pressure rating. Type L costs more than type M. Type L with its thicker walls weighs more and requires more copper, thereby costing more to manufacture and also to transport.
Type M: Red
The main difference between type M and L is the tube's wall thickness and its pressure rating. The two most common sizes for both Type L and Type M are half-inch and three-quarter-inch.
Copper pipes of the same type and size all have the same outside diameter, which allows them to use the same fittings for connections. The inside diameter varies by type due to the different thickness of the walls. For example, half-inch type M has an inside diameter of 0.569 inches and type L is 0.545 inches.