Assessment Level - TANK - Help - Hexagon PPM

Select the assessment level. See the description below that corresponds to your selection for Flaw Type.

Part 4 (General Metal Loss)

Select Level 1 and Level 2 if the following four points are true. Otherwise select Level 1 only or Level 2 only.

• The original design criteria was in accordance with a recognized code or standard (see Part 1, paragraphs 1.2.2 or 1.2.3).

• The metal loss region has relatively smooth contours without notches (that is, negligible local stress concentrations).

• The component is not in cyclic service.

A component is not in cyclic service if the component is subjected to less than 150 cycles throughout its previous operating history and future planned operation, or the component satisfies the cyclic service screening procedure in Annex B1, paragraph B1.5.2. A cycle is defined as pressure or temperature variations including operational changes and start-ups and shut-downs.

• The following limitations on component types and applied loads are satisfied:

  • Level 1 Assessment - Type A Components subject to internal pressure or external pressure (that is, supplemental loads are assumed to be negligible).

  • Level 2 Assessment - Type A or B Components (see Part 4, paragraph 4.2.5) subject to internal pressure, external pressure, supplemental loads (see Annex A, paragraph A.2.7), or any combination thereof.

Part 5 (Local Metal Loss)

Select Level 1 and Level 2 if the following five points are true. Otherwise select Level 1 only or Level 2 only.

• The original design criteria were in accordance with a recognized code or standard (see Part 1, paragraphs 1.2.2 or 1.2.3).

• The material is considered to have sufficient material toughness. If there is uncertainty regarding the material toughness, then a Part 3 assessment should be performed. If the component is subject to embrittlement during operation due to temperature or the process environment, a Level 3 assessment should be performed. Temperature or process conditions that result in material embrittlement are discussed in Annex G.

• The component is not in cyclic service.

A component is not in cyclic service if the component is subjected to less than 150 cycles throughout its previous operating history and future planned operation, or the component satisfies the cyclic service screening procedure in Annex B1, paragraph B1.5.2. A cycle is defined as pressure or temperature variations including operational changes and start-ups and shut-downs.

• The following limitations on component types and applied loads are satisfied:

  • Level 1 Assessment - Type A Components subject to internal pressure or external pressure (that is, supplemental loads are assumed to be negligible).

  • Level 2 Assessment - Type A or B Components (see Part 4, paragraph 4.2.5) subject to internal pressure, external pressure, supplemental loads (see Annex 2C, paragraph 2C.2.7), or any combination thereof.

• A flaw characterized as a groove in accordance with paragraph 5.2.1.b has a groove radius that satisfies the requirements in paragraph 5.4.2.2.f.

Part 6 (Pitting)

Select Level 1 and Level 2 if these six points are true. Otherwise select Level 1 only or Level 2 only.

• The original design criteria were in accordance with a recognized code or standard (see Part 1, paragraphs 1.2.2 or 1.2.3).

• The material is considered to have sufficient material toughness. If there is uncertainty regarding the material toughness, then a Part 3 assessment should be performed. If the component is subject to embrittlement during operation due to temperature and/or the process environment, a Level 3 assessment should be performed. Temperature and/or process conditions that result in material embrittlement are discussed in Annex G.

• The component is not in cyclic service.

A component is not in cyclic service if the component is subjected to less than 150 cycles throughout its previous operating history and future planned operation, or the component satisfies the cyclic service screening procedure in Annex B1, paragraph B1.5.2. A cycle is defined as pressure or temperature variations including operational changes and start-ups and shut-downs.

• The following limitations on component types and applied loads are satisfied:

  • Level 1 Assessment - Type A Components subject to internal pressure or external pressure (that is, supplemental loads are assumed to be negligible).

  • Level 2 Assessment - Type A or B Components (see Part 4, paragraph 4.2.5) subject to internal pressure, external pressure, supplemental loads (see see Annex 2C, paragraph 2C.2.7), or any combination thereof.

• Additional requirements for Level 1 assessments are:

  • The pitting damage is arrested.

  • The pitting damage is located on only one surface (either inside or outside) of the component.

  • The pitting damage is composed of many pits; individual pits or isolated pairs of pits should be evaluated using the assessment procedures in Part 5.

• Additional requirements for Level 2 assessments are:

  • The pitting damage is characterized by localized regions of pitting, an LTA located in a region of widely scattered pitting, or pitting that is confined within an LTA.

  • The pitting damage is located on either one surface or both surfaces of the component and the pitting damage is not overlapping (see Figure 6.3)

  • The pitting damage is composed of many pits; individual pits or isolated pairs of pits should be evaluated as LTAs using the assessment procedures in Part 5.

• A Level 2 only assessment should be performed if:

  • An appropriate pit comparison chart cannot be found (see paragraph 6.3.3.1).

  • A more detailed assessment of widespread pitting (inclusion of the pit-couple orientation) is required.