Interaction of RBI and FFS Technologies

Introduction

An overview of the interaction between two new technologies, Risk Based Inspection (RBI) and Fitness for Service (FFS) are presented. With the publication of API 579 Recommended Practice for Fitness for Service and the planned publication of API 580 Recommended Practice for Risk Based Inspection in 2001, these technologies will find increasing application in maintenance and inspection planning. There are relationships between the two. Applications of pro-active FFS assessments are highlighted.

The ASME and API design codes and standards for pressurized equipment provide rules for the design, fabrication, inspection and testing of new pressure vessels, piping systems, and storage tanks. API 510 Pressure Vessel Inspection Code, API 570 Piping Inspection Code, and API 653 in-service above ground storage tank inspection code and NBIC-23 provide requirements for in-service inspection of pressure vessels, piping, and tanks. Two new technologies have been developed to augment and enhance the use of these codes to provide safe and cost effective life management of aging equipment. These technologies, Risk Based Inspection (RBI) and Fitness for Service (FFS), have been developed over the past decade and have seen practical application within the refining and petrochemical industries. The API inspection Codes have been revised to allow the use of RBI for inspection planning (API 580) and will be revised later in 2001 to allow the use of FFS for assessment of flaws and other conditions (API 579).