Overview
There are two sets of models that calculate risk for columns; baseline and expanded. The following summarizes the capabilities of each set:
- Baseline models calculate risk for three risk components (Top, Middle, and Bottom) and then summarizes risk to recommend mitigation tasks.
- Expanded models calculate risk for multiple components as defined by the hierarchy and then summarizes risk to recommend mitigation tasks. The following components can be included in the hierarchy:
- up to 3 top sections (Top, Top 1, and Top 2)
- up to 3 middle sections (Middle, Middle 1, and Middle 2)
- up to 3 bottom sections (Bottom, Bottom 1, and Bottom 2)
- up to 10 other components that can represent various things such as nozzles, jackets, etc.
Baseline Asset (RBI_COLUMN)
Application
This parent asset model summarizes risk results from 3 components in a distillation column (Column Top, Column Middle and Column Bottom) to recommend mitigation tasks.
Mitigation recommendations were developed based on API 510 “Pressure Vessel Inspection Code” and API 572 “Inspection Practices for Pressure Vessels”.
Model Boundaries
This parent model summarizes risk analysis results from child components so mitigation tasks can be recommended for the asset. The worst child component determines the overall risk of the asset.
Link Models
This parent model should be linked to a hierarchy item where Type is “Asset”. The child components (Column Top, Column Middle or Column Bottom) must be linked to RBI_CYLINDRICAL.
Hierarchy Templates
The following hierarchy templates should be selected for the parent asset: Column – Metric (or SAE)
Dependencies
The child components must be children of the parent asset and be linked to RBI_CYLINDRICAL.
Expanded Asset (RBI_SP_COLUMN)
Application
This parent asset model summarizes risk results from up to 9 components in a distillation column (e.g. 3 components in each top, middle and bottom section) and up to 10 other components (e.g. jacket, nozzle) to recommend mitigation tasks.
This parent model can also be adapted to represent a horizontal pressure vessel where an accurate risk assessment requires multiple components to handle different operating conditions and/or different damage mechanisms. For example, a horizontal drum that separates mixed phase fluid could have 4 risk components: 1) two-phased flow near the inlet nozzle, 2) small portion of the shell opposite the inlet nozzle that has a liner to prevent erosion, 3) gas phase near top outlet nozzle and 4) liquid phase near bottom outlet nozzle that is behind a weir.
Mitigation recommendations were developed based on API 510 “Pressure Vessel Inspection Code” and API 572 “Inspection Practices for Pressure Vessels”. Two sets of recommendations are provided that address the overall asset and “worst” other components by damage mechanism.
Model Boundaries
This parent model summarizes risk analysis results from child components and other components so that mitigation tasks can be recommended for both the asset and other components. The worst child component determines the overall risk of the asset.
Link Models
This parent model should be linked to a hierarchy item where Type is “Asset”. The child components and other components must be linked to the following models:
- Column Top/Middle/Bottom: RBI_CYLINDRICAL
- Column Top 1 & 2/Middle 1 & 2/Bottom 1 & 2: RBI_SP_CYLINDRICAL
- Other components: RBI_SP_CYLINDRICAL
Hierarchy Templates
The following hierarchy templates should be selected for the parent asset: Column – Metric (or SAE)
Dependencies
The child components or other components must be children of the parent asset and be linked to either RBI_CYLINDRICAL or RBI_SP_CYLINDRICAL.
Baseline Child Components (RBI_CYLINDRICAL)
Application
This child model applies to column components Column Top, Column Middle and Column Bottom that must be children of the parent column asset which is linked to either RBI_COLUMN or RBI_SP_COLUMN.
The model is designed for pressure equipment constructed of cylindrical sections.
Mitigation recommendations are provided by the parent model (RBI_COLUMN or RBI_SP_COLUMN).
Model Boundaries
This child model applies to one risk component at a time.
The primary failure mode is loss of containment caused by one or many in-service damage mechanisms. Probability of failure categories are calculated for internal corrosion, external corrosion, corrosion under insulation and environmental cracking, but does not include the method for creep. Up to five additional damage mechanisms can be added manually as Other Damage Mechanisms.
A safety consequence of failure category is calculated based on one of four types of representative fluids: flammable, toxic, reactive (i.e. cause injury to skin upon contact such as acids, caustics and steam) or inert. An option allows a flammable fluid to also include a toxic mixture. If the representative fluid is inert and initial state is gas, then a burst consequence can be calculated. The user can also manually enter a production loss consequence to represent any type of financial loss. When both safety and financial consequence are included then the overall risk is based on the worst consequence.
Link Models
This child model should be linked to hierarchy items where Type is “Component” and parent is the column asset.
Hierarchy Templates
The following hierarchy templates should be selected for child components: Column Component – Metric (or SAE)
Dependencies
This model provides risk analysis results that are summarized by the parent asset (RBI_COLUMN or RBI_SP_COLUMN).
Expanded Child Components (RBI_SP_CYLINDRICAL)
Application
This child model applies to column components that must be children of the parent column asset.
NOTE: If the parent model is adapted for a horizontal pressure vessel, then this child model is applied to the child components, but Component Order will use terminology for column components.
The model is designed for pressure equipment constructed of cylindrical sections.
Mitigation recommendations are provided by the parent model (RBI_SP_COLUMN).
Model Boundaries
This child model applies to one risk component at a time.
The primary failure mode is loss of containment caused by one or many in-service damage mechanisms. Probability of failure categories are calculated for internal corrosion, external corrosion, corrosion under insulation and environmental cracking, but does not include the method for creep. Up to five additional damage mechanisms can be added manually as Other Damage Mechanisms.
A safety consequence of failure category is calculated based on one of four types of representative fluids: flammable, toxic, reactive (i.e. cause injury to skin upon contact such as acids, caustics and steam) or inert. An option allows a flammable fluid to also include a toxic mixture. If the representative fluid is inert and initial state is gas, then a burst consequence can be calculated. The user can also manually enter a production loss consequence to represent any type of financial loss. When both safety and financial consequence are included then the overall risk is based on the worst consequence.
Link Models
This child model should be linked to hierarchy items where Type is “Component” and parent is the column asset. This model provides the following expanded number of child components:
- Column Top 1 & 2 (these are distinct from the baseline child component "Column Top")
- Column Middle 1 & 2 (these are distinct from the baseline child component "Column Middle")
- Column Bottom 1 & 2 (these are distinct from the baseline child component "Column Bottom")
Hierarchy Templates
The following hierarchy templates should be selected for child column components: Column Component – Metric (or SAE)
Dependencies
This model provides risk analysis results that are summarized by the parent asset (RBI_SP_COLUMN).
Other Components (RBI_SP_CYLINDRICAL)
Application
This child model applies to Other components of the parent column asset such as jackets, nozzles, water boot, etc. must be children of the column asset.
The model is designed for pressure equipment constructed of cylindrical sections.
Mitigation recommendations are provided by the parent model (RBI_SP_COLUMN).
Model Boundaries
This child model applies to one risk component at a time.
The primary failure mode is loss of containment caused by one or many in-service damage mechanisms. Probability of failure categories are calculated for internal corrosion, external corrosion, corrosion under insulation and environmental cracking, but does not include the method for creep. Up to five additional damage mechanisms can be added manually as Other Damage Mechanisms.
A safety consequence of failure category is calculated based on one of four types of representative fluids: flammable, toxic, reactive (i.e. cause injury to skin upon contact such as acids, caustics and steam) or inert. An option allows a flammable fluid to also include a toxic mixture. If the representative fluid is inert and initial state is gas, then a burst consequence can be calculated. The user can also manually enter a production loss consequence to represent any type of financial loss. When both safety and financial consequence are included then the overall risk is based on the worst consequence.
Link Models
This child model should be linked to hierarchy items where Type is “Component” and parent is the column asset. This model provides up to 10 Other components (e.g. jackets, nozzles, etc.).
Hierarchy Templates
The following hierarchy templates should be selected for other components: Jacket without Creep – Metric (or SAE)
NOTE: The term “jacket” has been generalized to include any type of component including heating/cooling “jacket”, nozzles, water boot, etc.
Dependencies
This model provides risk analysis results that are summarized by the parent asset (RBI_SP_COLUMN).