Digital Application for Mechanical Integrity Assessment of Pressure Systems Subject to Pitting Corrosion

Abstract Pitting corrosion poses a major challenge to the safety and reliability of industrial pressure systems like pipelines. While detailed standards exist to assess this type of damage, particularly API 579-1/ASME FFS-1 Part 6, engineers find these manual assessments time-consuming and prone to calculation errors, potentially leading to safety risks or unnecessary repairs. The aim of the project was to develop a digital application that would make pitting corrosion assessments (fitness-for-service) faster, more accurate, and easier to perform while following the API 579-1/ASME FFS-1 Part 6 standard. This will enable engineers to make better decisions about equipment fitness for service, safety and maintenance. The application was developed using Python programming language with PyQt5 for the user interface. The development process involved analysing the API standard in detail, gathering feedback from practising engineers at Oceaneering, and implementing calculation modules for both Level 1 and Level 2 assessments. The application was tested and validated using real case studies from the API 579 Example Problem Manual. The results showed dramatic improvements in both speed and reliability. Level 1 assessments of widespread pitting, which typically require 1-1.5 hours to calculate manually, were completed in just 8 seconds by the application, a 99.85% reduction in time. More complex Level 2 assessments showed even greater time savings. An assessment involving pitting with supplemental loads that normally require 3-4 hours of manual calculation was completed in 10 seconds (99.93% faster), while a Level 2 assessment of local thin areas (LTA) with pitting was reduced from 4-5 hours to just 12 seconds, a 99.93% time saving. Even compared to other calculation methods like MS Excel (3-3.5 hours), MathCAD (2-3 hours), and Python scripts (1.5-2 hours), the application demonstrated superior performance with time savings exceeding 95% across all test cases. Importantly, the application maintained 100% accuracy compared to manual calculation results in the API 579 Example Problem Manual while achieving these speed improvements. These findings demonstrate that digital tools can significantly improve how the industry assesses pitting corrosion, enabling more frequent and thorough integrity assessments while reducing the risk of human error and the cost of these assessments. It also opens possibilities for better-informed maintenance decisions across the industry.