Which type of copper tubing has the thickest wall?

Type K copper tubing is known for having the thickest wall compared to other types of copper tubing used in various applications. It is designed for use in more demanding environments where higher pressure and greater durability are required, such as in underground systems and for propane and natural gas applications. The thickness of the wall provides extra resistance to the potential damage from physical impacts and corrosion, making it ideal for construction, industrial, and plumbing applications where longevity is needed.

In contrast, Type L copper tubing has a wall thickness that is less than that of Type K, and it is often used for water and gas applications. Type M has an even thinner wall and is primarily suited for residential water systems and some heating applications, where pressure and durability needs may not be as high. Type N, while not commonly referenced in standard industry practice, is typically not recognized in the same way as K, L, and M, further emphasizing Type K's position as the most robust option.