technical standards and legislation: risk based...
TRANSCRIPT
Technical Standards and Legislation:Risk Based Inspection
Presenter: Pierre Swart
Agenda
• Change in Legislation.
• Where RBI fits in.
• Application to implement RBI.
• RBI concepts.
• Elements of an RBI analysis.
• Keeping RBI evergreen.
Change in Legislation
With change from VUP regulation to PER in 2009, RBI is mandatory for vessels in corrosive service where inspection intervals above 36 months are required.
Pressure Equipment Regulation
Pressure Equipment
Regulation
PRESCRIPTIVE
=<36 monthsSELF REGULATING
>36 months
RBI
QA MANUAL
DEFINING RBI
SCHEME.
Management System
AUDIT/APPROVE
RBI SCHEME-
Certification
Body approved
by SANAS
Application to implement RBI
Formal application to DOL which includes:
• Copy of RBI management system.
• Name of chief RBI specialist and qualifications.
• RBI team competency and qualifications.
• Technical standard to be used.
• Name of Certification Body.
• Name of AIA.
• Letter of recommendation from AIA to implement RBI.
What is RBI?
Risk-Based Inspection (API 580)
Method using RISK as a basis for prioritising and managing of inspection programs
3 2
4
5
3
4 3
2
1 High
Medium
Low
Consequence
1
2
3
123
Basic Concepts
Basic Concepts
• Inspection program based on risk level.High risk items inspected more frequently and more stringently.
• Utilise the most appropriate inspection technique for the detection of identified degradation mechanisms.Understanding what degradation can occur, the most suitable inspection technique can be selected.
• Consider the likelihood of degradation mechanisms.Inspect only for the degradation mechanisms that have a probability of occurring.
Risk Based Approach
Environment
Contents
Loss of Containment
(Consequence)
Degradation Mechanism
(Probability/Likelihood)
Material
Basic Concepts
Basic Concepts
Deciding on the RBI approach will have a significant impact on resources and information required.
– Qualitative: less rigorous but also less resources and information.
– Semi-quantitative: Dependent on level of quantification. Benefit of less data and resources than quantitative but more data and resources than qualitative.
– Quantitative: Most data and resources required. Should only require this approach in specific cases.
What to consider if starting with RBI
Depends on level of assessment (Qualitative, Semi-quantitative and quantitative).
–Material of construction, insulation, cladding and design parameters such as pressures, temperatures.
–Operating parameters such as pressure, temperature and process fluid composition and properties.
–Population density, distance from water, towns.
–Mitigation measures such as bunds, shut off valves, fire brigade.
Elements of an RBI analysis
Data Collection for RBI Assessment
Data quality will influence accuracy of analysis.
Sources of data.
–Code data book.
–Process flow diagram
–Mechanical flow diagram
– Inspection records
Elements of an RBI analysis
Data Collection for RBI Assessment
Loss of Containment
–The consequence is determined as the effect of the fluid loss to the environment.
–Factors taken into account can be type of fluid, state of fluid, properties of fluid, process variables, mass of fluid, failure mode leak size.
Elements of an RBI analysis
Determine Consequences of Failure
Categories of consequence effects for loss of containment
– Safety and health impact (explosion; flash fire; pool fire; toxicity; pressure wave)
– Environmental impact. (liquid spills; vapour releases; ground water contamination)
– Business losses due to production loss and maintenance and reconstruction costs
Units of measure
– Quantitative analysis: expressed as numeric value.
– Qualitative analysis expressed as category, e.g high, medium, low or 1 through 5.
Elements of an RBI analysis
Determine Consequences of Failure
Probability of all deterioration mechanisms must be determined.
– Thinning: loss of material through corrosion and erosion
– Cracks: Stress Corrosion Cracking, Sulfide Stress Cracking, Hydrogen Induced Cracking
– Metallurgical and environmental: High Temperature Hydrogen Attack, Embrittlement, Metal Dusting.
– Mechanical: Mechanical Fatigue, Brittle Fracture.
Elements of an RBI analysis
Determine Probability of Failure
Units of measure in the probability of failure analysis
– Quantitative analysis: expressed as frequency, e.g. fixed interval (one per year, one in ten years) or as events per interval (0.0002 failures per year)
– Qualitative analysis uses categorisation, e.g high, medium, low or 1 through 5.
Determine Probability Of Failure (POF)
– Identify active and credible deterioration mechanisms.
– Determine deterioration susceptibility and rate.
– Quantify effectiveness of inspection and maintenance program
– Determine probability that with current condition, predicted deterioration will result in failure
Elements of an RBI analysis
Determine Probability of Failure
Determining risk
– Risk = Probability X Consequence
– Quantitative risk = sum of individual risks for each specific consequence, where
individual risks or risk of specific consequence = (probability of specific consequence) X (specific consequence).
– Qualitative risk = (overall probability rating) X (overall consequence rating)
Elements of an RBI analysis
Risk determination, Assessment and Management
Risk management decisions and acceptable levels of risk.
– Acceptable levels of risk determined by company.
– Use of RBI results to determine inspection programme.
Risk Presentation.
– Risk plot or Risk Matrix to help visualise the results of the study.
Elements of an RBI analysis
Risk determination, Assessment and Management
Managing risk by reducing uncertainty through inspection
– Where risk is driven by probability of failure, there is potential for risk management through inspection.
– Use of RBI results to determine what to inspect, how to inspect (technique), and extent of inspection (coverage).
– Therefore RBI results forms an input to the Equipment Maintenance Strategy (FMEA) of the equipment.
– In the FMEA specify mitigating actions to be taken if secondary action trigger requirements are met.
Elements of an RBI analysis
Risk management with inspection activities
Elements of an RBI analysis
Other risk mitigation activities.
Where inspection activities may not be sufficient, other mitigation activities could
include:
• Equipment repair, replacement or upgrade,
• Change in operating conditions,
• Equipment redesign.
Therefore the outputs of an RBI session can be integrated with other business
processes such as the life cycle management process for updating of renewal
plans, and the Integrity Operating Window process to manage production
parameters.
• RBI is a dynamic tool and should be updated when changes to the equipment or process occur or when new information becomes available as a result of inspection activities.
• Most damage mechanisms are time dependant and therefore the risk profile of the equipment will change over time.
Elements of an RBI analysis
Re-assessment and updating RBI assessments.
Keeping RBI evergreen
RBI meeting
RBI recommendations
FMEA
CMMS
Execution of Inspections
Inspection Report
External triggersLegislation changes, new
settlements close to plant, etc.
Internal triggersRequest for Delay, changes to equipment design or operating parameters, loss of
containment incidents, etc.
Health and safety standards for RBI as listed in SANS 347 Appendix A:
• API Recommended Practice 580: Risk-Based Inspection.
• ASME PCC-3-2007: Inspection Planning Using Risk Based Methods.
• CWA 15740: Risk-Based Inspection and Maintenance Procedures for European Industry (RIMAP)
References
Documents
