Select the type of damage observed from the following flaw types.
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Part 4 (General Metal Loss) - Select this option when the general metal loss (uniform or local, inside or outside) exceeds, or is predicted to exceed, the corrosion allowance before the next scheduled inspection. Assessments are based on point thickness readings and thickness profiles (see paragraph 4.3.3), whether the metal loss is uniform or local, and the degree of conservatism acceptable for the assessment. You can use the methodology shown in Figure 4.2 to determine the assessment procedure for the evaluation.
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Part 5 (Local Thinning Area) - Select this option when the metal loss on the surface of the component is localized, and the length of metal loss is about the same as the width.
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Part 5 (Groove like Flaw) - Select this option when the flaw is either:
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Groove - A local, elongated, thin-spot caused by directional erosion or corrosion. The length of the metal loss is significantly greater than the width.
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A sharp radius might be present at the base of a groove-like flaw.
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Gouge - A local, elongated, mechanical removal or relocation of material from the component surface resulting in a reduction in wall thickness at the flaw. The length of the gouge is much greater than the width. The material might have been cold worked in the formation of the flaw. Gouges are typically caused by mechanical damage, for example, denting and gouging of a section of pipe by mechanical equipment during the excavation of a pipeline. Gouges are frequently associated with dents due to the nature of mechanical damage. If a gouge is present, the assessment procedures of Part 12 shall be used.
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Part 6 (Pitting) - Select this option when one of the four types of pitting is present:
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widely scattered pitting over a significant region of the component,
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a local thin area (LTA) located within a region of widely scattered pitting,
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localized regions of pitting, and
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pitting confined within a region of an LTA.
The flowchart in Figure 6.2 provides details of the required assessment procedures. Depending on the type of pitting damage, you must use for evaluation either the assessment methods in Part 6 or a combination of assessment methods in Part 5 and Part 6.