API Spec 5L is an International Standard that specifies requirements for
the manufacture of two product specification levels (PSL 1 and PSL 2) of
seamless and welded steel pipes for use in pipeline transportation systems
in the petroleum and natural gas industries. This International Standard is
not applicable to cast pipe.
API Spec 5L is a modified national adoption of ISO 3183, 2nd Edition :
Petroleum and natural Gas Industries - Steel Pipe for Pipeline