risk-based inspection (rbi) by aminul islam

Risk Based

Inspection (RBI)

Prepared by: Md.Aminul Islam , CMRP, Reliability Engineer

Email: [email protected], Mob: +966-592475978

Md Aminul Islam, CMRP, [email protected] 1

mailto:[email protected]

What is Risk-Based Inspection (RBI)?

A risk assessment and management process that is focused on loss of containment of pressurized equipment in processing facilities due to material deterioration. These risks are managed primarily through equipment inspection.

The risk-based inspection is a systematic and integrated use of expertise from the different disciplines that impact plant integrity. These include design, materials selection, operating parameters and scenarios, and understanding of the current and future degradation mechanisms and risks involved.

Risk-based methodologies enable the assessment of the likelihood and potential consequences of equipment failures. Risk-Based Inspection (RBI) provides companies the opportunity to prioritize their equipment for inspection; optimize inspection methods, frequencies, and resources; and develop specific equipment inspection plans the extent of inspection, and the most suitable type of Non-Destructive Examination (NDE).

Md Aminul Islam, CMRP, [email protected]

2


RBI is most often used in engineering industries and is predominant in the oil and gas, petrochemical industries. Assessed risk level are used to develop a prioritised inspection plan. It is related to (or sometimes a part of) Risk Based Asset Management (RBAM), Risk Based Integrity Management (RBIM) and Risk Based Management(RBM).Generally, RBI is part of Risk and Reliability Management (RRM). Inspections typically employ non-destructive testing (NDT).

Risk-Based Inspection (RBI) is a methodology that, as opposed to condition-based inspection involves quantitative assessment of the Probability of failure (PoF) and the Consequence of failure (CoF) associated with each equipment item, piping circuits included, in a particular process unit.


3

https://inspectioneering.com/tag/probability+of+failure




https://inspectioneering.com/tag/consequence+of+failure




RBI is a risk assessment and management tool that addresses an area not completely addressed in other organizational risk management efforts such as Process Hazards Analyses (PHA) or reliability centered maintenance (RCM).

RBI produces Inspection and Maintenance Plans for equipment that identifies the actions that should be implemented to provide reliable and safe operation.

The RBI effort can provide input into an organization’s annual planning and budgeting that define the staffing and funds required to maintain equipment operation at acceptable levels of performance and risk.

Risk-Based Inspection is Proactive – It Utilizes the Information Available to Manage Risk


4

Purpose of Risk-Based Inspection

Screen operating units within a plant to identify areas of high risk.

Estimate a risk value associated with the operation of each piece of equipment

Prioritize the equipment based on the measured risk

Design an appropriate inspection program

Systematically manage the risk of equipment failures. *


5

Purpose of Risk-Based Inspection

*Systematically manage the risk of equipment failures.

1) To improve risk management results

2) To provide a holistic, interdependent approach for managing risks

3) To apply a strategy of doing what is needed for safeguarding integrity and improving reliability & availability of the asset by planning and executing those inspections that are needed

4) To reduce inspections and shutdowns and provide longer run length without compromising safety or reliability

5) To safeguard integrity

6) To reduce the risk of failures

7) To increase plant availability and reduce unplanned outages

8) To provide a flexible technique able to continuously improve and adopt to changing risks

9) To ensure inspection techniques and methods consider potential failure modes


6

Key Elements of a RBI Program

Key elements that should exist in any RBI program are: Management systems for maintaining documentation,

personnel qualifications, data requirements and analysis updates.

Documented method for probability of failure determination.

Documented method for consequence of failure determination.

Documented methodology for managing risk through inspection and other mitigation activities.


7

Equipment Covered in RBI

The following types of pressurized equipment and associated components/internals are covered by this document:

Pressure vessels—all pressure containing components.

Process piping—pipe and piping components.

Storage tanks—atmospheric and pressurized.

Rotating equipment—pressure containing components.

Boilers and heaters—pressurized components.

Heat exchangers (shells, heads, channels and bundles).

Pressure relief devices.


8

Equipment Not Covered in RBI

The following non-pressurized equipment is not covered by this document:

Instrument and control systems.

Electrical systems.

Structural systems.

Machinery components (except pump and compressor

casings).


9

Risk Analysis

A risk assessment involves first establishing the current and anticipated condition of the equipment, by asking the following questions:

• What material degradations have been experienced or could be experienced?

• What are the likelihood (probabilities) of these degradations occurring?

• What are the consequences of these degradations?

The next step is to determine the risk of operating equipment as the combination of two separate terms:

Risk = Likelihood or Probability of Failure x Consequence of Failure


10

Risk Analysis

• Likelihood - failure per year - needs to understand failure cause (at what point it fails).

The likelihood analysis assesses the probability and effects of specific failure mechanisms based on:

The history of the equipment

The history of similar or identical equipment in identical service conditions

• Consequence - need to understand failure mode (how it fails, what will result from failure).

Possible consequences:

1. Injury/fatality (safety) due to a toxic or flammable event

2. Environmental damage

3. Production Loss

4. Minimal impact (this is considered)

• In general, risk is calculated as a function of time as follows. R(t) =POF(t)*C(t) • The probability of failure is a function of time, since damage due to cracking, thinning or other damage mechanisms increases with time


11

Risk Analysis

• In API RBI, the consequence of failure is assumed to be independent of time, therefore

R(t)= POF(t)*CA …for Area Based Risk

R(t) = POF(t)*FC …for Financial Based Risk

• The Probability of Failure used in API RBI is:

POF(t) = Gff* Df(t)* Fms

POF(t)- the probability of failure as a function of time

Gff- Generic failure frequency

Df(t)- Damage factor as a function of time

Fms - Management systems factor


12

Risk Analysis

• The time dependency of probability of failure is the basis of using RBI for inspection planning

• Risk cannot be reduced to zero solely by inspection efforts. The residual risk factors for loss of containment include, but are not limited to, the following:

Human error.

Natural disasters.

External events (e.g., collisions or falling objects).

Secondary effects from nearby units.

Consequential effects from associated equipment in the same unit.

Deliberate acts (e.g., sabotage)

Fundamental limitations of inspection method.

Design errors.

Unknown mechanisms of deterioration.

Many of these factors are strongly influenced by the process safety management system in place at the facility.


13

Inspection Planning


14

Inspection Planning

Inspection plan is developed on a component basis Equipment is modelled as a group of individual components in API

RBI The final inspection plan for the equipment is based on the results

derived for the components The inspection plan includes: – The date and timing of the required

inspection, – The type of Inspection method(s) / NDE (e.g. Visual, UT, DPT, MPT, RT, ECT, WFMT) based on the active damage mechanisms – Extent of application of the inspection method(s) (e.g., % of total area examined or specific locations). – Location of inspection (external or internal) - Risk management achieved through implementation of the inspection plan.

The expected risk levels of all equipment after the inspection plan and other risk mitigation activities have been implemented.


15

Types of RBI Assessment

Various types of RBI assessment may be conducted at several levels. The choice of approach is dependent on multiple variables such as:

Objective of the study.

Number of facilities and equipment items to study.

Available resources.

Study time frame.

Complexity of facilities and processes.

Nature and quality of available data.

RBI is both a qualitative and quantitative process for systematically combining both the likelihood of failure and the consequence of failure to establish a prioritized list of pressure equipment basis total risk. Three levels of risk based inspection have been developed by API for prioritizing risk levels associated with individual pieces of pressure equipment.


16


Qualitative Risk Analysis (Assessment): Methods that use engineering judgment and experience as the bases for the analysis of probabilities and consequences of failure. The results of qualitative risk analyses are dependent on the background and expertise of the analysts and the objectives of the analysis. Failure Modes, Effects, and Criticality Analysis (FMECA) and HAZOPs are examples of qualitative risk analysis techniques that become quantitative risk analysis methods when consequence and failure probability values are estimated along with the respective descriptive input.

Semi-quantitative Risk Analysis (Assessment): This is an intermediate method of quantitative RBI, for risk ranking individual pieces of equipment in a process unit. It’s also uses a risk matrix for displaying risk analysis results. Semi-quantitative RBI analysis asks more questions, and therefore takes more time to accomplish, but results in more accuracy and avoids overly conservative risk ranking that may result from simpler methods.


17


Quantitative Risk Analysis (Assessment): An analysis that:

Identifies and delineates the combinations of events that, if they occur, will lead to a severe accident (e.g., major explosion) or any other undesired event.

Estimates the frequency of occurrence for each combination.

Estimates the consequences.

Quantitative risk analysis integrates into a uniform methodology the relevant information about facility design, operating practices, operating history, component reliability, human actions, the physical progression of accidents, and potential environmental and health effects, usually in as realistic a manner as possible. Quantitative risk analysis uses logic models depicting combinations of events that could result in severe accidents and physical models depicting the progression of accidents and the transport of a hazardous material to the environment. The models are evaluated probabilistically to provide both qualitative and quantitative insights about the level of risk and to identify the design, site, or operational characteristics that are the most important to risk. Quantitative risk analysis logic models generally consist of event trees and fault trees. Event trees delineate initiating events and combinations of system successes and failures, while fault trees depict ways in which the system failures represented in the event trees can occur. These models are analysed to estimate the frequency of each accident sequence


18

Planning the RBI Assessment

A RBI assessment is a team-based process. At the beginning of the exercise, it is important to define:

Why the assessment is being done

How the RBI assessment will be carried out.

What knowledge and skills are required for the assessment.

Who is on the RBI team.

What are their roles in the RBI process.

Who is responsible and accountable for what actions.

Which facilities, assets, and components will be included.

What data is to be used in the assessment.

What codes and standards are applicable.

When the assessment will be completed.

How long the assessment will remain in effect and when it will be updated.

How the results will be used.


19

Steps in applying RBI principles within

the framework:

1. Planning the RBI Assessment.

2. Define the Scope

3. Establish the Team

4. Roles, Responsibilities, Training and Qualifications.

5. Create an Equipment List

6. General Equipment Data and Information Collection.

7. Identifying Deterioration Mechanisms and Failure Modes.

8. Assessing Probability of Failure.

9. Assessing Consequence of Failure.

10. Risk Determination, Assessment and Management.

11. Risk Management with Inspection Activities and Risk Benefit.

12. Other Risk Mitigation Activities.

13. Reassessment and Updating.

14. Documentation and record-keeping.


20

Benefits of RBI

• A ranking by risk of all equipment evaluated.

• A description of any other risk mitigation activities (such as repairs, replacements or safety equipment upgrades).

• An overall reduction in risk for the facilities and equipment assessed.

• An acceptance/understanding of the current risk.

• Improved health, safety and environment management

• Avoiding unnecessary inspection – Inspection intervals are based on the risks associated with the equipment and therefore inspection personnel can spend most of their time on the high risk areas and less time in the low risk areas.

• Cost saving – Equipment with no history of problems and no anticipated problems is inspected on longer intervals rather than just inspecting every few years as is the case with a time-based inspection program.


21

Benefits of RBI

• Information from inspections on one piece of equipment can be utilized in determining the inspection intervals and scopes for similar equipment.

• The RBI program is totally dynamic: risks are updated after inspections or even the inspection of similar equipment, changes to process conditions or even if new information becomes available. Any of the above may result in a change in inspection frequencies or changes to the inspection scopes.

• The methods used to determine the inspection intervals and inspection scopes are documented and repeatable.

• Reliability and compliance with applicable Codes/Standards

• Increasing plant availability and optimum repair and replacement scheduling

• Extended plant and equipment life.


22

ESTIMATING RESOURCES AND TIME

REQUIRED

The resources and time required to implement a RBI assessment will vary widely between organizations depending on a number of factors including:

Implementation strategy/plans.

Knowledge and training of implementers.

Availability and quality of necessary data and information.

Availability and cost of resources needed for implementation.

Amount of equipment included in each level of RBI analysis.

Degree of complexity of RBI analysis selected.

Degree of accuracy required.


23

ESTIMATING RESOURCES AND TIME

REQUIRED

The estimate of scope and cost involved in completing a RBI assessment might include the following:

Number of facilities, units, equipment items, and components to be evaluated.

Time and resources required to gather data for the items to be evaluated.

Training time for implementers.

Time and resources required for RBI assessment of data and information.

Time and resources to evaluate RBI assessment results and develop inspection, maintenance, and mitigation plans.


24

Data needed for a RBI analysis

Typical data needed for a RBI analysis may include but is not limited to: Type of equipment.

Materials of construction.

Inspection, repair and replacement records.

Process fluid compositions.

Inventory of fluids.

Operating conditions.

Safety systems.

Detection systems.

Deterioration mechanisms, rates and severity.

Personnel densities. k. Coating, cladding and insulation data.

Business interruption cost.

Equipment replacement costs.

Environmental remediation costs.


25

Potential sources of information

1. Design and Construction Records/Drawings. P&IDs, PFDs, MFDs, etc.

Piping isometric drawings.

Engineering specification sheets.

Materials of construction records.

Construction QA/QC records.

Codes and standards used.

Protective instrument systems.

Leak detection and monitoring systems

Isolation systems.

Inventory records.

Emergency depressurizing and relief systems.

Safety systems.

Fire-proofing and fire fighting systems.

Layout.


26


2. Inspection Records. Schedules and frequency.

Amount and types of inspection.

Repairs and alterations.

PMI records.

Inspection results.

3. Process Data. Fluid composition analysis including contaminants or trace

components

Distributed control system data.

Operating procedures.

Start-up and shut-down procedures.

Emergency procedures.

Operating logs and process records.

PSM, PHA, RCM and QRA data or reports.


27


4. Management of change (MOC) records.

5. Off-Site data and information—if consequence may affect off-site areas.

6. Failure data. Generic failure frequency data—industry or in-house.

Industry specific failure data.

Plant and equipment specific failure data.

Reliability and condition monitoring records.

Leak data.

7.Site conditions.

Climate/weather records.

Seismic activity records.


28


8. Equipment replacement costs.

Project cost reports

Industry databases.

9. Hazards data.

PSM studies.

PHA studies.

QRA studies.

Other site specific risk or hazard studies.

10. Incident investigations


29

Risk Based Inspection - In the context

of RCM

** 1. Special knowledge & expertise required

2. Team structure is different to RCM (Mech, materials/corrosion, ops, process, inspection)

3. Some failure modes happen over long period RBI start

RCM Functional Failure Mode-1

Functional Failure Mode-2

Functional Failure Mode-3 :Loss of containment**


30

Reassessment and Updating RBI

RBI is a dynamic tool that can provide current and projected future risk evaluations. However, these evaluations are based on data and knowledge at the time of the assessment. As time goes by, changes are inevitable and the results from the RBI assessment should be updated. It is important to maintain and update a RBI program to assure the most recent inspection, process, and maintenance information is included. The results of inspections, changes in process conditions and implementation of maintenance practices can all have significant effects on risk and can trigger the need to perform a reassessment.

Reasons to Conduct an RBI Reassessment: There are several events that will change risks and make it prudent to conduct a RBI reassessment. It is important that the facility have an effective management of change process that identifies when a reassessment is necessary.

Deterioration Mechanisms and Inspection Activities – Process & Hardware changes – RBI Assessment Premise Change – Effect of Mitigation Strategies


31

Reassessment and Updating RBI

When to Conduct an RBI Reassessment:

After significant changes – After a set Time Period – After Implementation of Risk Mitigation Strategies – Before and After Maintenance Turnarounds

Additional Reasons for Re-evaluation

Changes in RBI technology or improvements that affect the risk calculation – Changes in code that affect the recommendations – Changes in law or regulatory policies – Change in company risk policy – Process changes, includes debottlenecking, changes in feed, changes in catalyst, changes in alloying, etc. – Considerations as learned from a failure in that plant or another plant with a similar process – Extension of run length between turnarounds


32

Five Critical Success Factors for “Best

Practice” RBI Program

1. Successful RBI Tool Implementation

2. Develop Operational Documents

3. Execute a Transition Phase

4. Establish a Training Program

5. Sustain and Review RBI Program

Other Key Information to Achieve Best Practice

Each RBI Program should have Four Phases

1. Implement

2. Transition

3. Sustain

4. Review/Measure


33

Codes and Standards

International engineering standards and recommended practices outline requirements, methodologies and the implementation of RBI.

1. API 580 Risk Based Inspection Recommended Practice.

2. ASME PCC3 Inspection Planning Using Risk Based Methods.

3. API 581 Risk Based Inspection Resource.

4. DNV-RP G101Risk Based Inspection Of Offshore Topsides Static Mechanical Equipment.

5. API 571 Damage Mechanisms Affecting Fixed Equipment in the Refining Industry


34

CONCLUSION

RBI provides a logical, documented, repeatable methodology for determining the optimum combination of inspection frequencies and inspection scopes. RBI objective is to ensure focus of inspection to areas with high risk, while inspection in areas with low risk will be reduced or excluded from the normal inspection program and therefore result in significant inspection and maintenance cost reduction.


35


36