The American Petroleum Institute specification API 5L covers seamless and welded steel line pipe. This is steel pipe for pipeline transportation systems in the petroleum and natural gas industries. API 5L is suitable for conveying gas, water, and oil. Size range is limited only by manufacturer’s capabilities.

Specifications for API 5L adhere to the International Organization for Standardization ISO 3183, which standardizes pipeline transportation systems within the materials, equipment and offshore structures for petroleum, petrochemical, and natural gas industries.

Grades covered by this specification are A25 ,A ,B (and the following “X” Grades), X42, X46, X52, X56, X60, X65, X70, X80. The two digit number following the “X” indicates the Minimum Yield Strength (in 000’s psi) of pipe produced to this grade.