Petrochem/Utilities Industry Trends

Fitness for Service: If It Ain't Broke, Don't Fix It

Issue Table of Contents

Risk-Based Inspection Paves the Way for Risk Reduction and Cost Savings Fitness for Service: If It Ain't Broke, Don't Fix It A Lesson in Equipment Safety: Q&A with Greg Alvarado RBI & FFS Standards and Related Publications

Not all equipment flaws are created equally. At least that is the premise of fitness-for-service (FFS), a new methodology designed to help refining and chemical companies extend the life of their processing equipment. Based on guidelines established by the American Petroleum Institute (API) in Recommended Practice 579 (RP 579), FFS can help companies make better, more informed decisions regarding the repair and replacement of equipment. Already, the guidelines have saved the industry significant operating costs as companies have reduced the amount of unnecessary repairs to their equipment and avoided unnecessary plant downtime.

The FFS methodology provides assessment procedures that allow companies to determine the usability of flawed equipment. These guidelines show engineers how to take into consideration a number of factors — such as equipment operating conditions, material composition, and type of flaw — to determine whether the piece of equipment in question can keep operating and under what conditions, or whether it needs to be repaired or replaced. More accurate analysis procedures based on FFS let companies make more informed decisions about equipment safety and performance.

While FFS assessments help engineers make cost-saving decisions about whether or not damaged equipment can remain in service, they also provide value by allowing engineers to measure the safety of equipment used in situations for which they were not designed. Since manufacturers typically only provide guidelines for use of their equipment in specific situations, FFS can therefore help companies extend the usability of their existing equipment while continuously ensuring its safe deployment.

FFS assessments, it can be seen, save companies money by extending equipment life. Beyond that, however, they can also enhance plant safety. Since unnecessary repairs to equipment can sometimes do more harm than good, FFS helps companies prolong the safe operating life of their processing equipment by offering more precise feedback on whether or not any repairs are necessary to keeping equipment in service. Only when it is deemed that equipment can no longer operate safely under current conditions will it be pulled for repair or replacement.

Included in API RP 579 are procedures on how to evaluate flaws or areas of damage commonly found in pressurized equipment, such as corrosion, pitting, blisters and laminations, brittle fractures, metal loss, crack-like flaws, long-term creep damage, and fire damage. Based on the calculations and analysis provided by these procedures, engineers can determine if a particular piece of equipment is safe to operate under current conditions or if those conditions must be modified. RP 579 also includes three levels of assessment for each type of flaw, with more complex calculations at the higher levels allowing for more precise analysis. Assessments made by following lower level procedures are more conservative, but also easier to do.

RP 579 was created by a committee of industry experts from owner/user companies and consulting organizations. First released in 2000, it can be used with other guidelines such as RP 580, Risk-based Inspection, to meet government regulations, extend equipment life, improve operations, and save money.