AS3788 2006 to 2024 Risk-based Inspection

2024 Revision preface points out that one of the "major changes" in this edition is as follows: (c) Revision of inspection requirements including risk -based inspection. So what's changed lets have a look.

Here are my "points to note" I'm sure you will have yours.

2006 Appendix B Risk Management (informative) has been dropped in 2024 and now mostly lies within the main body of the document.

Operation (In-service): Internal and external inspection (Clause 4.4.3): Provide assurance that the equipment remains in safe working order. The inspection is performed at intervals determined by either Table 4.1 or through a risk -based inspection methodology in accordance with Section 4.5.

The comparison between the 2006 and 2024 versions of AS 3788 regarding the requirements for Risk-Based Inspection (RBI) reveals several key differences and similarities. Below is a detailed comparison and contrast of these two versions.

Similarities:

Alternative to Fixed Intervals:

Both versions recognize RBI as an alternative to the fixed inspection intervals provided in Table 4.1 of the standard.

Multidisciplinary Involvement:

Both versions emphasize the need for a multidisciplinary team when conducting RBI, involving roles such as inspectors, corrosion engineers, process engineers, mechanical engineers, and operations representatives.

Consideration of Risks and Defects:

Both versions require consideration of risks associated with fabrication, construction defects, and actual service conditions on equipment design and materials of construction.

Differences:

General Approach and Structure:

2006 Version: The approach to RBI is more general, emphasizing the agreement between the owner and the inspection body, preparation of risk assessment documentation, and transparent justifications for any deviations from standard inspection practices.

2024 Version: The 2024 version provides a more structured and detailed approach, specifying the minimum requirements for RBI, including detailed clauses on conditions for adoption, conducting assessments, inspection planning, and reassessment.

Detailed Methodology:

2006 Version: The methodology is less prescriptive, focusing on general conditions such as agreement and documentation. Appendix B has been dropped.

2024 Version: The 2024 version section 4.5 Risk-based inspection introduces detailed requirements for conducting RBI, including:

Determining the Probability of Failure (PoF) considering specific factors like damage mechanisms, materials, operational conditions, and inspection effectiveness.

The probability of failure (PoF) shall be determined, as a minimum, by considering the impact of each of the following:

(a) Damage mechanisms present, taking into account the following:

(i) Materials of construction.

(ii) Fluid contents.

(iii) Operational conditions.

(iv) Rate of deterioration.

(b) Form and extent of damage.

(c) Inspection effectiveness.

(d) Inspection findings.

Determining the Consequence of Failure, with a minimum focus on health, safety, and the environment, but allowing for additional categories such as financial impact and reputation.

The consequence of failure shall be determined, as a minimum, by considering the impact of failure in the following categories:

(a) Health.

(b) Safety.

(c) Environment.

Any other categories of consequence may be included. Such categories may include

o financial impact,

o equipment damage,

o reputation,

o regulatory matters, and

o loss of production.

Conditions for adopting risk-based inspection methodology

A risk-based inspection methodology may be used for all pressure equipment provided

(a) the methodology is documented;

(b) the methodology is undertaken by competent persons with specific knowledge of the type of plant being assessed, appropriate for the task (e.g., inspection, corrosion engineering, mechanical engineering, process engineering, maintenance, operations);

(c) consideration is given to design, manufacture, transit, storage, installation and preservation imperfections; and

(d) a change management process exists which ensures changes in process conditions, operating mode, equipment design or materials of construction are captured, assessed and addressed.

Inspection Planning and optimization.

2006 Version: The 2006 version does not explicitly mention of inspection plans.

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2024 Version: The 2024 version emphasizes developing an optimized inspection plan based on the risk assessment, ensuring the inspection scope and interval are proportionate to the assessed risk.

4.5.4 Inspection planning and optimization

An important part of developing an optimized inspection plan is the ability to determine the most appropriate inspection methods and/or monitoring program that is proportionate to the assessed risk.

The output of the risk-based inspection process is an inspection scope for each equipment item as detailed in Clause 2.3.4 and an inspection interval commensurate with the risk level determined for the equipment.

Reassessment and Change Management:

2006 Version: The concept of reassessment or change management is not explicitly covered.

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2024 Version: The 2024 version requires a reassessment of the RBI program at set intervals, after inspections, or following significant changes in process conditions, inspection findings, or identification of new degradation mechanisms. It also introduces a change management process to address any changes in process conditions, operating modes, or equipment design. "4.5.5 Risk-based Inspection Reassessment The risk-based inspection program shall be maintained to ensure that it accounts for the most recent inspection and monitoring, process, and maintenance information. Risk-based inspection reassessment shall be carried out either at a set interval, or after every inspection activity, and additionally after the following:

(a) Changes to inputs/factors in the risk-based inspection assessment.

(b) Process excursions outside acceptable limits.

(c) Adverse inspection findings.

(d) The identification of new degradation mechanisms.

(e) Repairs, modifications, alterations, or re-rating."

Transportable Vessels:

2006 Version: The standard does not specifically mention transportable vessels in the context of RBI.

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2024 Version: The 2024 version specifies that while RBI principles may supplement inspection methods for transportable vessels, they cannot be used to extend inspection intervals beyond those specified in the table.

Inspection Date Compliance:

2006 Version: There is no explicit mention of reverting to time-based intervals or conditions for inspection date compliance.

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2024 Version: The 2024 version allows RBI intervals to revert to time-based intervals under certain conditions, ensuring compliance with the time-based inspection intervals if the RBI interval is greater or equivalent to the standard intervals. Inspection intervals determined using a risk-based inspection methodology may revert to the time-based inspection intervals in Clause 4.4 and Table 4.1 provided —

(a) the risk-based inspection interval is greater than or equivalent to the time -based inspection intervals in Columns 4 and 5 of Table 4.1; and

(b) the equipment has been internally and externally inspected where required by Column 3 of Table 4.1.

Summary:

The 2006 version provides a more general framework for RBI, focusing on agreement, documentation, and the involvement of a multidisciplinary team.

In contrast, the 2024 version introduces a more detailed and structured (in the main body) approach, specifying minimum requirements, conditions for adopting RBI, conducting assessments, and maintaining a dynamic and optimized inspection plan. The 2024 version also introduces the concept of reassessment and a change management process, reflecting a more comprehensive and systematic approach to RBI.

However the 2006 3788 APPENDIX B RISK MANAGEMENT (Informative) has been dropped and no further mention of "qualitative and quantitative processes and systematically combine both the likelihood of failure and the consequences of failure to establish a prioritized list of pressure equipment on the basis of total risk."

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