Inline Integrity: Pipeline Weld Inspection According to API 1104

The Importance of Perfect Pipe Welding

Gas and oil pipelines are the arteries of the energy industry. A failure in a single weld can have devastating consequences, both economic and operational. Therefore, rigorous inspection of each joint is not optional—it is a critical necessity to ensure safe and continuous operation.

The Gold Standard: API 1104

The API 1104, "Welding of Pipelines and Related Facilities" standard is the worldwide reference code for the construction and inspection of pipeline welds. This document establishes the procedures and quality standards that must be followed to ensure the structural integrity of the line.

Primary Inspection Methods

To evaluate the quality of pipeline welds, API 1104 recognizes several NDT methods, the most commonly used being:

• Radiography (RT): A traditional and reliable method that provides a permanent record (a film) of the internal quality of the weld.
• Phased Array Ultrasound (PAUT): An advanced technique that offers immediate results, high sensitivity to critical defects such as cracks, and excellent sizing capability. It is often used to accelerate construction timelines.
• Magnetic Particle Testing (MT) and Liquid Penetrant Testing (PT): Used for inspection of the root pass and final surface of the weld.

Acceptance Criteria: What Is a Rejectable Defect?

Not every imperfection is a defect that compromises the pipeline. Section 9 of API 1104 precisely defines the limits for discontinuities such as porosity, slag inclusions, lack of fusion, and cracks. Our certified inspectors use these criteria to objectively determine whether a weld is acceptable or must be repaired.

Conclusion

At Compañía Técnica, we rigorously apply API 1104 standards and the most advanced inspection methods to give our clients the certainty that their pipelines will operate safely and efficiently throughout their service life.

How we apply this in the field

At Compañía Técnica this translates into concrete work: industrial ultrasonic testing and phased array, carried out with our own equipment, deployable anywhere in Argentina, and a report signed by a technical representative registered with the Energy Secretariat. The full catalogue of non-destructive testing sets out the scope of each one.

Sources and reference standards

• American Petroleum Institute (API) — publisher of the API 653, API 1104 and API 579 standards
• American Society for Nondestructive Testing (ASNT) — international reference on NDT methods and qualification