PLSS Hierarchy

Take note
This article explains how the Hierarchy is implemented in IMS PLSS and the IMS PLSS Workflow.

The IMS Hierarchy is designed to implement the Degradation Management work process. Specifically, IMS PLSS defines when and what to inspect while maintaining a complete audit trail of the inspection results.

In IMS PLSS, the “when” is defined by an Equipment Inspection Schedule event. The inspection results are captured in the Equipment Condition History (ECH). Users review which schedules are due—those with scheduled dates approaching or on the current date—and then perform the required inspections, capture the inspection results and credit the Schedule(s) in the ECH.

In case of recurring Schedule(s), a new Schedule will automatically be created with a new due date.

The figures below show the important objects and how the flow between the different objects occurs.

Locations

Locations are organized in Site – Plant – Unit – Functional Location (FLOC). These are the highest hierarchy levels in IMS. The FLOC typically has specific operating parameters: flow rates, temperatures, pressures, fluid composition. FLOC IDs never change, at least until the Unit or the FLOC is retired.

Generally, each FLOC has one child, which is a piece of Equipment (with an Equipment ID). Some FLOCs cover more than one Equipment group, e.g. For Exchangers-FLOCs two separate pieces of Equipment can be assigned: a Bundle and an Exchanger. The Equipment, in turn, might contain Circuits and/or Components. Some data will or can be inherited from a higher level (e.g. Inspection Reason is inherited from the FLOC down to Equipment and Circuits).

When you click the Hierarchy button, the Hierarchy side panel opens and shows a tree view of the full Site (from the Site to the level of corrosion Circuits and Components). See Other IMS Main Menu Options.

Site Plant Unit (Toplevel)

Details for Sites, Plants, and Units are registered and organized in Settings\Company\Toplevel. See Configuring the Toplevel via Settings.

FLOCs

The Functional Locations (FLOCs) are registered in the FLOC Main Screen. See PLSS Functional Locations (FLOCs).

Equipment

An Equipment object represents a physical piece of Equipment, which can be measured, having specific materials, coatings, dimensions, weld joints, etc. An Equipment is designated to a FLOC and contains both Circuits and/or Components. An Equipment ID is valid until the Equipment is replaced. When replaced, a new Equipment ID will be assigned. For sites using the GSAP interface, the FLOCs and Equipment cannot be entered directly into IMS. The hierarchy information for these sites is determined by GSAP.

Various types of Schedules can be registered for an Equipment and are shown in the Schedules section. Default Schedules are automatically created when a new piece of Equipment is added and act as a “safety net” for which the minimal time interval should be set (12 months).

For more information, see PLSS Equipment.

Schedules

Schedules can be assigned to both Equipment and Circuits. On the Equipment level, there are Inspection, CAIR, or RBI Re-assessment Schedules, while for Circuits only Corrosion Schedules are assigned. All inspection Schedules can be credited by adding and approving ECHs, which include detailed information about the inspection performed. The Corrosion Schedules are credited by calculating and Approving the Calc Summary.

For more information, see PLSS Schedules and Step 13 Barrier Verification - Execute, Analyze, Document.

Condition Histories (ECHs)

Equipment Condition Histories (ECHs) are registered for a piece of Equipment and capture the inspection findings, using Checklists and a narrative. Approving the ECH will credit possible Inspection Schedules and create new Schedules for the Equipment when the credited Schedule is recurring. The user can fill out Checklists that will show the inspection condition and repairs performed, depending on the Schedules scope or Inspection Strategy (IS) (i.e. looking for certain Degradation Mechanism).

For more information, see PLSS Condition History (ECH).

Systems

In IMS PLSS, the Systems group together the Equipment that operates within the same process or pipeline network into a unified group. Within each System, Equipment are the primary assets managed for integrity, with Barriers implemented to protect against the Threats posed by Degradation Mechanisms (DMs). These DMs are subject to circumstances (i.e. IOWs such as temperature, pressure, fluids) in or around the Equipment. Degradation Mechanisms (DM), Barriers, and Integrity Operating Windows (IOWs) are defined on the System level, enabling Systems to support the Corrosion Management Framework (CMF).
Each System is assigned a parent FLOC of the type "PLSS System FLOC”.

IMS PLSS Workflow

The steps outlined below describe IMS’s structured process for Pipeline integrity management, designed to streamline Inspection, Assessment, and Corrective activities.

FLOC - First the hierarchy is set up in IMS, starting with Site – Plant – Unit and FLOC.
Equipment – Also the Equipment must be defined as part of the hierarchy. If interfaced with a CMMS (Computerized Maintenance Management Software) like SAP, then the hierarchy (Site – Plant – Unit – FLOC - Equipment) will come from there. For Pipeline, Flowline, and Pipeline Jumper Equipment you should add additional design data: Most important is the Minimum Allowable Operating Temperature (MAOP), Assessment Strategy (AS) and Consequence of Failure (CoF). This is needed for the RBA Assessment.
System – Next you need to define the System. The System is used to group Equipment that are part of a Pipeline or Subsea System together. Assign all applicable Equipment to the System. Also define the System’s applicable Degradation Mechanisms (DMs), Barriers (CMF) and Integrity Operating Windows (IOWs). From time to time the System should be updated and reviewed in terms of the Barrier Statuses.
FFS – Next (after an ILI run has been completed) you can start the Fitness For Service Assessment. After opening the FFS module you need to start a new Assessment – this is done by creating an ECH and importing the Pipe Tally and/or Dig-up data (see step 5). Then you need to ensure that the imported Wall Thickness (WT) matches the WT specified in IMS. If the WTs do not match, create or updates the Pipe data Section to align IMS with the Pipe Tally data. Once this is complete, the Corrosion Tolerance (CT) and values as Safe Working Pressure (SWP) are calculated, and you need to Final Approve the Condition History.
Equipment Condition History (ECH) - Create an ECH with Inspection Date as the Condition date and the Assessment Code. First, convert the Pipe Tally data to an IMS PLSS import file. Then import this file.
ILI Comparison – When two new ILI runs (already imported via the FFS module – step 4) are available for comparison, create a Scenario in the ILI Comparison module, then import the girth weld data for both runs. During the ILI comparison calculation, the defects from both ILI runs will be matched, and the short-term Corrosion Rate (CR) will also be calculated automatically. You can review and adjust defect matches.
Internal Corrosion Assessment – Next, you can start the Internal Corrosion Assessment. This can be done per section. After opening the Internal Corrosion module, you need to start a new Assessment – this is done by creating an ECH. Various data sources, including ILI run results (both long- and short-term Corrosion Rates), Probe data (which can be imported via another ECH), Hydrocor results, Degradation Mechanisms and Barriers can be reviewed. Based on this analysis, you need to specify the Past and Future Corrosion Rates, define the defect morphology, and fill in the Confidence Rating questionnaire.
External Corrosion Assessment - Next, you can start the External Corrosion Assessment. This can be done per section. After opening the External Corrosion module, you need to start a new Assessment – this is done by creating an ECH. Various data sources, including ILI run results (both long- and short-term Corrosion Rates), CP data, CIPS data, DCVG data, and others, Excor results, Degradation Mechanisms and Barriers can be reviewed. Based on this analysis, you need to specify the Past and Future Corrosion Rates and Defect morphology, and fill in the Confidence Rating questionnaire. Recurring Assessment Schedules can be used to plan the corrosion assessments.
Risk Based Assessment (RBA) – Go to the RBA module to review the results - IMS automatically calculates the Equipment’s worst Remaining Life (RL) and Next Inspection Date (NID) based on Equipment design data (MAOP, Assessment Strategy & Consequence of Failure), the FFS output (Corrosion Tolerance), and the Internal & External Corrosion Assessment outputs (Past CRs, Future CRs & Confidence Ratings). Note: If there’s no ILI run or no Defect is present in a section, IMS calculates the CT based on the LimState. Also, an Integrity Status (traffic light) is determined based on the worst Remaining Life. This can be overwritten via an ECH. (For other types of Equipment, like Risers, for which RBA is not assessed, the Integrity Status can also be set via an ECH.)
Inspection Schedule – An Inspection Schedule for an In-Line Inspection (ILI) based on the worst NID determined in the RBA should be then either be created or updated if you are working with recurring Schedules. This needs to be done manually.
Scenario Assessment – Adjusting parameters like MAOP, number of repair Defects, and Confidence rating in the Scenario Assessment Module can help to test the effects of those changes on RL and the NID. After the Assessment is done, the tested Scenario can be applied in the field. This also helps to prioritize the defects and determine how many have to be repaired.
Remedial Action – You can now use the Remedial Actions module to determine which defects will be repaired and when, i.e., plan the repairs. CAIR(s) should be created (see step 15) for the Planned Repairs. When the repair has been executed, i.e., the ECH was final approved (see step 16), this should be indicated in the remedial action module. This action will trigger the recalculation of the FFS, which will update the CT and consequently the RBA generated Integrity Status.
CAIR Schedule – To repair a defect you need to plan it by creating a CAIR Schedule.
ECH – When the CAIR Schedule is executed and the Defect repaired, you need to credit it with an ECH. When the ECH is approved, the CAIR will become inactive.
3PD – You can use the Survey module to enter and manage your Depth of Cover (DoC) data for buried Pipelines ensuring they are adequately covered to prevent external corrosion and other forms. The Third-Party Damage (3PD) tab under Equipment Sectioning can be used to define the Design DoC per Section.
Findings – CAIR – Depending on the findings during an inspection, a corrective action may be needed. For this, you will need to create a CAIR Schedule.
Findings – Anomaly – Findings can also be registered as Anomalies via the ECH observations. These Anomalies can be managed via the Anomaly module. To monitor an Anomaly, a recurring Inspection Schedule can be created. When the time comes to monitor the Anomaly, the Schedule should be credited with an ECH. This will create a new Inspection Schedule.