Which type of copper tubing is the thickest?

The type of copper tubing that is the thickest is type K. Type K copper tubing is designed for applications requiring a greater wall thickness, which provides enhanced strength and durability. This thickness makes it suitable for high-pressure applications and is often used in underground installations and for construction purposes where vulnerability to damage is a concern.

Type K tubing has the largest inside and outside diameter among the common types, making it ideal for long-lasting installations, particularly in plumbing and heating systems. The thickness of the walls also contributes to better resistance to corrosion over time, which is a significant factor in maintaining the integrity of the piping system.

In contrast, the other types of copper tubing—L, M, and N—have progressively thinner walls, with type M being the thinnest used primarily for residential plumbing. Each type has its specific applications based on wall thickness and pressure allowances, but type K is recognized for its robustness, making it the correct choice in this scenario.