What is psl1 and pls2 grade pipe?

PSL 1 and PSL 2 are two product specification levels defined by the American Petroleum Institute (API) in the API 5L standard for line pipes used in the oil and gas industry. PSL 1 is the basic level that covers minimum requirements for the pipe's chemical composition, mechanical properties, and testing methods. PSL 2 includes all the requirements of PSL 1 but adds stricter criteria for chemical composition, mechanical properties, and additional testing requirements, making it suitable for more demanding applications.