What is the API 1104 standard for pipeline welding?

The API 1104 (American Petroleum Institute) standard is the reference for welding pipelines and related facilities. It is used in Quebec for gas and oil pipelines.

Differences from CSA W59:

• API 1104 is specific to pipelines — butt joints of steel pipes
• Stricter acceptance criteria for certain defects
• Requires a specific Welding Procedure Specification (WPS) qualification

Key points of API 1104:

• Positions: Circular (5G, 6G) pipe welding
• Root pass: Typically with E6010 (deep penetration, fast speed)
• Fill passes: E7018 or self-shielded flux-cored wire
• Qualification test: destructive tests (guided bend, tensile) and radiographic inspection — the extent of inspection is the one the project prescribes

Radiographic rejection criteria (API 1104):

• The acceptance thresholds — size and cumulative length of porosity and slag indications — are tabulated in the acceptance criteria of API 1104, according to defect type and size: they are not summed up by a single percentage.
• Lack of fusion and cracks: any indication of that nature is a ground for rejection.