Linear Indication

A defect or indication whose length is significantly greater than its width, such as a crack or lack of fusion in a weld. Linear indications are potentially more serious than rounded indications of equivalent area because stress concentrations are more severe. Linear indications in fatigue-critical applications require more stringent acceptance criteria. Proper measurement and characterization of linear indication length is essential for flaw evaluation.

Detection and Assessment

Linear Indication must be detected early and accurately characterized to determine safety implications. Multiple NDT methods may be required for comprehensive evaluation.

Acceptance Criteria

Industry standards such as ASME Section V, AWS D1.1, and API standards provide specific acceptance limits. Whether a detected linear indication is acceptable depends on material, component function, and applicable code.

Best Practices

• Always follow applicable NDT standards and procedures
• Use properly calibrated and maintained equipment
• Ensure personnel are properly trained and certified
• Document inspection procedures and results completely
• Keep current with industry standards and best practices