WRC 599

Significant inconsistencies and inadequacies exist in the current brittle fracture screening procedures included in the various ASME and API codes and standards used in the design and fabrication of pressure vessels and piping. Similar issues exist in the API 579-1/ASME FFS-1, Fitness-For-Service International Code (API 579), reference [1]. This Bulletin will provide an overview of the critical parameters that influence susceptibility to brittle fracture, and it will provide detailed review of several significant brittle fracture failures that have occurred in industry. The Bulletin will provide a summary of the current design and Fitness-For-Service (𝐹𝐹𝑆) procedures that are used to screen for the propensity for brittle fracture in pressure vessels and piping and the background for these procedures will be thoroughly documented. The Bulletin will highlight the numerous inconsistencies and deficiencies with the current procedures. New brittle fracture screening procedures anchored in state-of-the art fracture mechanics will be introduced along with the technical basis and justification for the new procedures. The applicability and limitations of the new procedures will be explicitly noted and examples demonstrating implementation of the new procedures will be provided. The newly proposed procedures are intended for consideration in the design and construction of new pressure vessels and piping systems as well as for implementation in post-construction 𝐹𝐹𝑆 Assessments of existing equipment and piping.