THE VALUE OF INSPECTION

Introduction

For over 100 years the oil & gas industry has been stablishing standards to enhance operational safety, environmental protection, and sustainability. A key development has been the implementation of the inspections to foresee potential damages to fixed equipment. The American Petroleum Institute (API) provides the petroleum and petrochemical industries an independent means to assess the skills and experience of technical and inspection personnel through its Individual Certification Programs (ICP) established from 1989. building on this, API 581 combines preexisting inspection concepts with statistical models to predict when potential damages could escalate into a significant issue.

Trustworthy inspections

The focus on inspections has intensified, honing in on identifying specific damages by considering various variables. Notably, operational conditions (temperature, pressure, phase, and fluid type) and design specifications of equipment (materials, maximum allowable working pressure, minimum design metal temperature, nominal thickness) are pivotal. all historical data recorded until today has empowered a deeper level of analysis, utilizing statistical tools to enhance inspection effectiveness, minimizing the uncertenty.

Inspection effectiveness, as defined by API 581, measures the ability of inspection activities to reduce uncertainty in equipment damage assessment. This essentially gauges how well inspections detect anticipated damages. Categorizing inspections into different levels of effectiveness (referred to as Level of Inspection Effectiveness or LoIE) provides a true value assessment of inspections. These categories are instrumental in determining the Damage Factor (DF), a key variable in calculating the probability of failure according to RBI methodologies outlined in API 581.

It's worth noting that categorizing inspections isn't solely for installations with an RBI implemented; it can also aid in standardizing inspection processes for planning purposes. Many owner/users may not be familiar with this categorization approach, and even those who do may not fully grasp the statistical depth behind each category. API 581 attempts to simplify this with Table 2.C.2.1.

While DFs are valuable for predicting potential damage over time and evaluating inspection effectiveness, it's crucial to recognize their limitations—they don't offer a definitive assessment of equipment fitness for service. Instead, they serve as predictive tools. Educating stakeholders on the importance of inspection categorization and statistical analysis can improve asset management practices and contribute to safer operations.

API 581 has created tables featuring examples for various equipment and damage mechanisms, which are located in Annex 2.C—Levels of Inspection Effectiveness within the standard. However, it's important to note that these tables serve as examples only. It is the responsibility of the owner/user to customize them for their specific cases, requiring the expertise of a subject matter expert to define the appropriate scope for each category.

Conclusion

The meticulous categorization of inspections is fundamental for ensuring confidence in the inspection process, as well as in associated RBI and inspection plans. While API 581 provides tables as examples, it's essential for owners/users to adapt these to their specific cases with the guidance of subject matter experts. Even if categorization hasn't been done yet, there's still an opportunity to leverage historical data and implement effective planning strategies. By maintaining comprehensive records and considering variables such as man-hours and supplies, organizations can enhance their overall approach to inspections, ultimately promoting safety, reliability, and cost-effectiveness in industrial operations.