Dtibo,
Product Specification Level (PSL) in API5L, define different levels of standard technical requirements. Appendix F provides supplementary requirements.
for example, talking about grades:
PSL 1 pipe can be supplied in Grades A25 through X70
PSL 2 pipe canb be supplied in Grades B through X80
for dimensions:
PSL 1 pipe can be supplied in size ranging from 0.405 through 80
PSL 2 pipe can be supplied in sizes ranging from 4½ through 80.
See Paragraph 1.2 and Table 1.