What color mark is used to indicate hard drawn type L copper tubing?

The color blue is used to indicate hard drawn type L copper tubing, which is recognized as a standard practice in plumbing and plumbing codes. Type L copper tubing is thicker than Type M and is typically used for both residential and commercial applications due to its strength and durability. The blue marking helps plumbers and contractors easily identify the type of tubing being used on a job site, ensuring that the appropriate materials are selected for various plumbing systems. Proper identification of tubing types is essential in avoiding errors during installation and ensuring that the plumbing system meets regulatory compliance and safety standards. This marking system also assists in inventory management and helps ensure that the correct tube is selected for various applications, benefiting both efficiency and safety in plumbing practices.