API 5L

In detail

API 5L is the American Petroleum Institute specification for line pipe used in oil and gas pipeline transportation systems. It defines two product specification levels: PSL 1 (standard quality) and PSL 2 (mandatory chemical composition, notch toughness, and non-destructive testing). The standard covers grades from B to X70 with increasing yield strength, and includes provisions for sour service (NACE MR0175) for hydrogen sulfide environments.

Where you'll meet this in procurement

You will meet API 5L when a buyer, consultant, or mill quote names a governing specification. Confirm which revision applies, what tests the standard requires, and whether the grade on the MTC actually matches the API 5L call-out on the RFQ before you lock commercial terms.

Related terms

• NACE MR0175International standard for materials resistant to sulfide stress cracking in sour service.
• LSAW (Longitudinal Submerged Arc Welded)Pipe with straight longitudinal weld made by submerged arc welding of formed plate.
• HSAW (Helical Submerged Arc Welded)Spiral-welded pipe formed by helical winding of steel coil with submerged arc welding.
• SeamlessPipe without weld seam, manufactured by hot-piercing solid steel billet.
• TPI (Third-Party Inspection)Independent inspection by agencies like SGS, BV, or Lloyds for quality verification.

Related resources

• Steel pipe standards library
• Request a quotation (RFQ)
• Back to full glossary