INTRODUCTION TO RISK BASED INSPECTION

WHAT IS RISK?Risk may be characterized as the product of probabilityof a given failure event (likelihood of failure, LOF) and the consequences of that event if it were to occur (COF).

Risk = COF x LOF

The consequences of failure can be expressed in terms of the physical damages, production delays or shortfalls, casualties, or the monetary equivalents of these items.

RISK BASED INSPECTIONRisk Based Inspection1 (RBI) is 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.

RBI can be used to continuously improve the inspection of facilities and systematically reduce the risk associated with pressure boundary failures. It offers the added advantage of identifying gaps or shortcomings in the effectiveness of commercially available inspection technologies and applications.

[1] API Recommended Practice 580 Risk Based Inspection, pg. 6.

RISK BASED INSPECTIONRBI produces Inspection and Maintenance Plans for equipment that identifies the actions that should be implemented to provide reliable and safe operation. By factoring risk into inspection and maintenance decision making, the RBI process is focused on maintaining the mechanical integrity of pressure equipment items and minimizing the risk of loss of containment due to material deterioration.

RISK BASED INSPECTION

Why Do We Need RBI?Most inspection codes/standards based on LOF, not COFReduce risk of high consequence failuresImprove the cost effectiveness of inspection and maintenance resourcesProvide a basis for shifting resources from lower to higher risk equipmentMeasure and understand the risks associated with current inspection programsMeasure risk reduction as a result of inspectionpractices

QUANTIFYING INSPECTABLE RISKLIKELIHOOD OF EVENTXCONSEQUENCE=RISKGeneric FailureFrequencyDamage FactorAgeDamageMechanism(s)& RatesInspectionEffectivenessInjury ($)Downtime ($)Item repair ($)Env. clean up ($)Adjacent repairs ($)TOTAL ($)

Un-Inspectable Contributors to RiskHuman errorNatural disastersExternal events (e.g. collisions or falling objects)Secondary effects from nearby unitsDeliberate acts (e.g. sabotage)Inherent risk in handling hazardous materialsInspection method detectability

Management of Risk using RBIRISKLevel of Inspection ActivityUn-inspectable riskRisk with typical inspection programRisk using RBI

TYPES OF RBI ANALYSISLevel 0Qualitative Risk AnalysisSimple, Brief Prioritization of Plants, Units or Sub UnitsLevel IQualitative Risk AnalysisSimple, Brief Prioritization of EquipmentLevel IISemi-Quantitative Risk Analysis More Detailed Prioritization of EquipmentLevel IIIQuantitative Risk Analysis Most in Depth Analysis and Prioritization of Equipment

QUALITATIVE APPROACH TO RBIThis approach requires data inputs based on descriptive information using engineering judgment and experience as the basis for the analysis of probability and consequence of failure. Inputs are often given in data ranges instead of discrete values. Results are typically given in qualitative terms such as high, medium and low, or low numerical values may be associated with these categories.

SEMI-QUANTITATIVE RISK MATRIX LEVEL II

QUANTITATIVE RISK BASED INSPECTIONINSPECTIONPROGRAMPLANT EQUIPMENT DATA FILEPSM / PHAASSESSMENTSPROCESSCONDITIONSMANAGEMENTSYSTEMSEQUIPMENTEVALUATIONGENERIC EQUIPMENTFAILURE DATA BASEPROBABILITY OF FAILURE ANALYSISCONSEQUENCEANALYSISRISK PRIORITIZATIONCONSEQUENCEMITIGATIONINSPECTION PROGRAMIMPROVEMENTSPROCESS SAFETYMANAGEMENTIMPROVEMENTS

RELATIONSHIP WITH API INSPECTION CODES AND STANDARDSAPI-RP 580 Risk Based Inspection Recommended Practice is integrated with:API-510 Pressure Vessel Inspection CodeAPI-570 In-Service Piping Inspection CodeAPI-653 Storage Tank Inspection Standard

RBI CoversPressure Vessels all pressure containing componentsProcess Piping pipe and piping components Storage Tanks atmospheric and pressurizedRotating Equipment pressure containing componentsBoilers & Heaters pressurized componentsHeat Exchangers (shells, heads, channels and bundles)Pressure Relief Devices

RBI Does Not CoverInstrument & Control systemsStructural systemsElectrical systemsMachinery components (except pump and compressor casings)

WHERE INSPECTION CAN HELP

WHERE DOES RBI FIT INTO OUR CURRENT INSPECTION PRACTICES?RECORDSUPDATINGINSPECTIONRESULTSINSPECTIONEXECUTIONFITNESSFOR SERVICE

Page 1 - Introduction to RBITHE LIKELIHOOD OF AN EVENT AND THE CONSEQUENCE OF AN EVENT.Given two similar vessel the one in the more corrosive service is the more likely to leak if they are left alone. Without any knowledge of the rate of degradation, the probability of failure cannot be confidently known. Good inspection defines the exact situation and allows for mitigation.THE TYPE OF CONSEQUENCES WHICH CAN CONSIDERED ARE SAFETY, ENVIRONMENTAL AND BUSINESS INTERRUPTION.SOME LEAKAGES FOR INSTANCE MIGHT HAVE AN IMPACT ON ALL THREE, OTHER EVENTS MIGHT HAVE NO SIGNIFICANT IMPACT.THE RBI METHODOLOGY HELPS TO IDENTIFY THE KEY EVENTS AS WELL AS THE INSPECTION ACTIVITY NEEDED TO ASSIST to PREVENT A RELEASE.THE KEY TO ACHIEVING THIS IS THE IDENTIFICATION - AND CHARACTERISATION OF - ACTIVE DEGRADATION MECHANISMS WHICH ALLOWS TIMELY PM TASKS TO BE PERFORMED. WHILE THE RBI APPROACH CAN MAKE A SIGNIFICANT CONTRIBUTION TO THE REDUCTION OF RISK, THERE ARE SOME AREAS WHERE IT CANNOT HELP (... NEXT SLIDE) Page 2 - Introduction to RBIPage 2 - Acceptance of RBIPage 4 - Acceptance of RBIPage 1 - Acceptance of RBIFOR INSTANCE OPERATIONAL ERRORS,PROCESS UPSETSAND DESIGN ERRORS

WHILE THE RBI SYSTEM CANNOT HELP WITH THIS, IT IS EXPECTED THAT THE OVERALL PSM/MI SYSTEM WILL THROUGH THE PROVISION OF:

WELL CONSTRUCTED PROCEDURESAND THE PROPER TRAINING OF STAFF IN THE PROCEDURES

SO THAT TOGETHER THE COMBINATION OF RBI WITH A PSM SYSTEM ASSISTS TO CONTROL MOST RISKS.