Fitness-for-Service Analysis Procedure – Determine Flaw Size and Orientation
1. Determine actual flaw size, configuration, and orientation using ultrasonic examination procedures.
2. Resolve the flaw into a simple shape by completely circumscribing with an ellipse or circle.
a. Circumscribe multiple flaws with the same ellipse or circle if the distance separating them is less than the dimension of the largest flaw in the same direction as the separation is measured.
3. Project circumscribed flaw onto a plane perpendicular to the direction of the maximum principal stress.
a. Flaws closer to a surface than 0.4 times their maximum dimension in a direction perpendicular to the surface are classified as surface flaws.
b. Flaws further from a surface than 0.4 times their maximum dimension in a direction perpendicular to the surface are classified as internal flaws.
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