Fitness-For-Service Assessment (FFS)
FFS assessments are quantitative engineering evaluations that are performed to demonstrate the structural integrity of an in-service component that may contain a flaw or damage. We provides services for conducting FFS assessments based on API 579-1/ASME FFS-1 using methodologies specifically prepared for pressurized equipment. The service could be used to make run-repair-replace decisions to help determine if pressurized equipment containing flaws that have been identified by inspection can continue to operate safely for some period of time. These FFS assessments are currently recognized and referenced by the API Codes and Standards (510, 570, & 653), and by NB-23 as suitable means for evaluating the structural integrity of pressure vessels, piping systems and storage tanks where inspection has revealed degradation and flaws in the equipment.
The assessment service may also be applied to pressure containing equipment constructed to other recognized codes and standards, including international and internal corporate standards.
This service has broad application since the assessment procedures are based on allowable stress methods and plastic collapse loads for non-crack-like flaws, and the Failure Assessment Diagram (FAD) Approach for crack-like flaws.
The Fitness-For-Service assessment cover both the present integrity of the component given a current state of damage and the projected remaining life. Assessment techniques are included to evaluate flaws including: general and localized corrosion, widespread and localized pitting, blisters and hydrogen damage, weld misalignment and shell distortions, crack-like flaws including environmental cracking, lamination, dents and gouges, and remaining life assessment procedures for components operating in the creep range. In addition, evaluation techniques are provided for condition assessment of equipment including resistance to brittle fracture, long-term creep damage, and fire damage.
In addition, both qualitative and quantitative methods for establishing remaining life and in-service margins for continued operation of equipment could be provided in regards to future operating conditions and environmental compatibility.
Risk-Based Inspection (RBI)
RBI is synonymous with risk-prioritized inspection, risk-informed inspection and with inspection planning using risk based methods. Inspection planning is a systematic process that begins with identification of facilities or equipment and culminates in an inspection plan. Both the probability of failure and the consequence of failure should be evaluated by considering all credible damage mechanisms that could be expected to affect the facilities or equipment. In addition, failure scenarios based on each credible damage mechanism should be developed and considered.
The output of the inspection planning process conducted should be an inspection plan for each equipment item analyzed that includes:
a) inspection methods that should be used,
b) extent of inspection (percent of total area to be examined or specific locations),
c) inspection interval or next inspection date (timing),
d) other risk mitigation activities,
e) the residual level of risk after inspection and other mitigation actions have been implemented.
The RBI plan service provided by RPA, combined with a comprehensive set of integrity operating windows for each process unit and a rigorous MOC (management of change) program could provide the basis for sound management of the integrity of fixed equipment in the refining and petrochemical process industry.
The primary work products of the RBI assessment and management approach are plans that address ways to manage risks on an equipment level. These equipment plans highlight risks from a safety/health/environment perspective and/or from an economic standpoint. It also include cost-effective actions along with a projected risk mitigation.
The RBI plans also identify equipment that does not require inspection or some other form of mitigation because of the acceptable level of risk associated with the equipment’s current operation. In this way, inspection and maintenance activities can be focused and more cost effective. This often results in a significant reduction in the amount of inspection data that is collected. This focus on a smaller set of data should result in more accurate information. In some cases, in addition to risk reductions and process safety improvements, RBI plans may result in cost reductions.
Utilization of RBI provides a vehicle for continuously improving the inspection of facilities and systematically reducing the risk associated with pressure boundary failures. As new data (such as inspection results and industry experiences with similar processes) becomes available or when changes occur (e.g. operating conditions), reassessment of the RBI program can be made that will provide a refreshed view of the risks. Risk management plans should then be adjusted appropriately.
RBI offers the added advantage of identifying gaps or shortcomings in the effectiveness of commercially available inspection technologies and applications. In cases where technology cannot adequately and/or cost-effectively mitigate risks, other risk mitigation approaches can be implemented. RBI should serve to guide the direction of inspection technology development, and hopefully promote a faster and broader deployment of emerging inspection technologies as well as proven inspection technologies that may be available but are underutilized.
RBI is a risk assessment and management tool that addresses an area of risk management not completely addressed in other organizational risk management efforts such as process hazards analyses (PHA), integrity operating windows (IOWs) or reliability centered maintenance (RCM). Integration of these risk management efforts, including RBI, is key to the success of a risk management program.
RBI produces inspection and maintenance plans for equipment that identify the actions that should be taken 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.
RBI needs to be integrated with a management system for defining and maintaining IOWs as well as a robust management of change (MOC) process as a basis for managing and controlling damage mechanisms in fixed equipment.
Pressure Equipment Integrity Incident Investigation
Investigation is a vital element for learning from unexpected discoveries or incidents (e.g. finding significantly more corrosion damage or other forms of deterioration than expected) and can be used in a continuous improvement process. Investigating and determining the causes of unexpected leaks, equipment degradation, or near misses associated with pressure equipment may be used to improve mechanical integrity programs and management systems for maintaining Pressure Equipment Integrity (PEI), such as design and construction procedures, maintenance and inspection practices, and operating practices.
The investigation principles and concepts of PEI are specifically targeted for application to process pressure equipment in the refining and petrochemical industry but could be applied to other equipment at the discretion of the owner/user.
Significant mechanical integrity incidents are rarely the result of one isolated issue; there are almost always less severe precursors to a major failure. These precursors are frequently called near misses when they are found. It`s important to recognize these precursor occurrences and promotes investigating them to determine the immediate, contributing, and root causes. If these precursor occurrences are uncovered, investigated, and the contributing and root causes are resolved, then major catastrophic failures of pressure equipment could be minimized or prevented.
