Overview
There are two sets of models that calculate risk for shell and tube exchangers (aka ST Exchangers); baseline and expanded. The following summarizes the capabilities of each set:
- Baseline models calculate risk for three risk components (Shell, Channel, and Bundle) 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 shell sections (Shell, Shell 1, and Shell 2)
- up to 3 channel sections (Channel, Channel 1, and Channel 2)
- up to 3 bundles (Bundle, Bundle 1, and Bundle 2)
- up to 10 other components that can represent various things such as nozzles, jackets, etc.
Baseline Asset (RBI_ST_EXCHANGER)
Application
This parent asset model summarizes risk results from 3 components (Shell, Channel and Bundle) 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 must be linked to the following models:
- Shell and Channel: RBI_CRP_CYLINDRICAL
- Bundle: RBI_ST_BUNDLE
Hierarchy Templates
The following hierarchy templates should be selected for the parent asset: Shell & Tube Exchanger – Metric (or SAE)
Dependencies
The child components must be children of the parent asset (See RBI_CRP_CYLINDRICAL and RBI_ST_BUNDLE).
The sequence of running models is important for Shell and Tube Exchangers. The following order must be followed:
- Shell and Channel components must be run BEFORE the Bundle.
- Bundle component must be run AFTER Shell and Channel because it retrieves information from the Driving scenarios for the Shell and Channel components.
- Parent asset (RBI_ST_EXCHANGER) is run LAST to summarize risk from child components.
Expanded Asset (RBI_SP_ST_EXCHANGER)
Application
This parent asset model summarizes risk results from up to 9 components (e.g. 3 each for shell, channel, and bundle components) and up to 10 other components (e.g. jacket, nozzle) to recommend mitigation tasks.
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:
- Shell and Channel: RBI_CRP_CYLINDRICAL
- Shell 1 & 2 and Channel 1 & 2: RBI_SP_CRP_CYLINDRICAL
- Bundle: RBI_ST_BUNDLE
- Bundle 1 & 2: RBI_SP_ST_BUNDLE
- Other components: RBI_SP_CRP_CYLINDRICAL
Hierarchy Templates
The following hierarchy templates should be selected for the parent asset: Shell & Tube Exchanger – Metric (or SAE)
Dependencies
The child components must be children of the parent asset.
The sequence of running models is important for Shell and Tube Exchangers. The following order must be followed:
- Shell and Channel components must be run BEFORE the Bundle.
- Bundle components must be run AFTER Shell and Channel because it retrieves information from the Driving scenarios for the Shell and Channel components.
- Parent asset (RBI_ST_EXCHANGER) is run LAST to summarize risk from child components.
Baseline Shell & Channel (RBI_CRP_CYLINDRICAL)
Application
This child model applies to Shell & Tube Exchanger Shell and Channel components that must be children of the parent asset which must be linked to RBI_ST_EXCHANGER or RBI_SP_ST_EXCHANGER.
Mitigation recommendations are provided by the parent model (RBI_ST_EXCHANGER or RBI_SP_ST_EXCHANGER).
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, environmental cracking and 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 ST Exchanger asset.
NOTE: The corresponding Bundle component must be linked to RBI_ST_BUNDLE.
Hierarchy Templates
The following hierarchy templates should be selected for the child components: Shell & Tube Exchanger Channel and Shell – Metric (or SAE)
Dependencies
This model provides risk analysis results that are summarized by the parent asset (RBI_ST_EXCHANGER or RBI_SP_ST_EXCHANGER).
Baseline Bundle (RBI_ST_BUNDLE)
Application
This child model applies to one representative tube in a Shell & Tube Exchanger Bundle that must be a child of the parent asset linked to either RBI_ST_EXCHANGER or RBI_SP_ST_EXCHANGER. Typically, the representative tube is the “worst” tube to result in conservative mitigation recommendations.
Mitigation recommendations are provided by the parent model (RBI_ST_EXCHANGER or RBI_SP_ST_EXCHANGER).
Model Boundaries
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, and environmental cracking, but does not include the method for CUI or creep. Up to five additional damage mechanisms can be added manually as Other Damage Mechanisms.
A safety consequence of failure category is calculated for flammable or toxic leak types based on where downstream of the exchanger the released fluid is no longer contained. A product leak financial consequence of failure category can be calculated, and the user can also manually enter a production loss consequence to represent any type of financial loss. When safety and financial consequences are included then the overall risk is based on the worst consequence.
Link Models
This child model should be linked to a hierarchy item where Type is “Component” and parent is the Shell & Tube Exchanger.
Corresponding Shell and Channel components must be linked to RBI_CRP_CYLINDRICAL. This bundle model cannot retrieve data from the “SP” models.
Hierarchy Templates
The following hierarchy templates should be selected for the parent asset: Shell & Tube Exchanger Bundle – Metric (or SAE)
Dependencies
This model provides risk analysis results that are summarized by the parent asset (See RBI_ST_EXCHANGER or RBI_SP_ST_EXCHANGER).
This model retrieves data from baseline components Shell and Channel that are linked to RBI_CRP_CYLINDRICAL.
The sequence of running models is important for Shell and Tube Exchangers. The following order must be followed:
- Shell and Channel components must be run BEFORE the Bundle.
- Bundle component must be run AFTER Shell and Channel because it retrieves information from the Driving scenarios for the Shell and Channel components.
- Parent asset (RBI_ST_EXCHANGER) is run LAST to summarize risk from child components.
Expanded Shell & Channel (RBI_SP_CRP_CYLINDRICAL)
Application
This child model applies to Shell & Tube Exchanger Shell and Channel components that must be children of the parent asset which must be linked to RBI_SP_ST_EXCHANGER.
Mitigation recommendations are provided by the parent model (RBI_SP_ST_EXCHANGER).
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, environmental cracking and 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 ST Exchanger asset. This model provides the following expanded number of child components:
- Shell 1 & 2 (these are distinct from the baseline child component "Shell")
- Channel 1 & 2 (these are distinct from the baseline child component "Channel")
NOTE: The corresponding Bundle component(s) must be linked to RBI_SP_ST_BUNDLE.
Hierarchy Templates
The following hierarchy templates should be selected for the asset: Shell & Tube Exchanger Channel and Shell – Metric (or SAE)
Dependencies
This model provides risk analysis results that are summarized by the parent asset (RBI_SP_ST_EXCHANGER).
Expanded Bundle (RBI_SP_ST_BUNDLE)
Application
This child model applies to two representative tubes in a Shell & Tube Exchanger Bundle that must be a child of the parent asset linked to RBI_SP_ST_EXCHANGER. Typically, each representative tube is the “worst” tube in each bundle to result in conservative mitigation recommendations.
Mitigation recommendations are provided by the parent model (RBI_SP_ST_EXCHANGER).
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, and environmental cracking, but does not include the method for CUI or creep. Up to five additional damage mechanisms can be added manually as Other Damage Mechanisms.
A safety consequence of failure category is calculated for flammable or toxic leak types based on where downstream of the exchanger the released fluid is no longer contained. A product leak financial consequence of failure category can be calculated, and the user can also manually enter a production loss consequence to represent any type of financial loss. When safety and financial consequences are included then the overall risk is based on the worst consequence.
Link Models
This child model should be linked to a hierarchy item where Type is “Component” and parent is the Shell & Tube Exchanger. This model provides the following expanded number of child components:
- Bundle 1 & 2 (these are distinct from the baseline child component "Bundle")
Corresponding Shell and Channel components must be linked to RBI_SP_CRP_CYLINDRICAL. This bundle model only retrieves data from “SP” components and cannot retrieve data from the baseline model (RBI_CRP_CYLINDRICAL).
Hierarchy Templates
The following hierarchy templates should be selected for the parent asset: Shell & Tube Exchanger Bundle – Metric (or SAE)
Dependencies
This model provides risk analysis results that are summarized by the parent asset linked to RBI_SP_ST_EXCHANGER.
This model retrieves data from “SP” components (i.e. Shell 1, Shell 2, Channel 1 and Channel 2) that are linked to RBI_SP_CRP_CYLINDRICAL.
The sequence of running models is important for Shell and Tube Exchangers. The following order must be followed:
- Shell and Channel components must be run BEFORE the corresponding Bundle.
- Bundle component must be run AFTER Shell and Channel because it retrieves information from the Driving scenarios for the Shell and Channel components. Bundle 1 gets results from Shell 1 and Channel 1 and likewise for Bundle 2.
- Parent asset (RBI_SP_ST_EXCHANGER) is run LAST to summarize risk from child components.
Other Components (RBI_SP_CRP_CYLINDRICAL)
Application
This child model applies to other components such as jackets, nozzles, water boot, etc. that must be children of the parent asset which must be linked to RBI_SP_ST_EXCHANGER.
Mitigation recommendations are provided by the parent model (RBI_SP_ST_EXCHANGER).
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, environmental cracking and 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 ST Exchanger asset. This model can be used for up to 10 other components (i.e. jackets, nozzles, etc.) where each component is a separate hierarchy item.
Hierarchy Templates
The following hierarchy templates should be selected for the asset: Jacket with 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_ST_EXCHANGER).