scope:

Introduction

The current ASME B31.8 standard ("the Code") requires no derating of line pipe steels for temperatures below 250°F. For pipeline steels in the Grade X60-X70 range, data show that a reduction of the yield strength may be exhibited at temperatures below 250 °F in some cases. For example, Figure 1 presents a reduction in measured yield strength with increasing temperature above 50°C (122°F) in high strength line pipe observed by one manufacturer. Some pipeline design standards developed for other countries (e.g., Norway, Netherlands, and Australia) already apply derating factors at temperatures well below 250°F. Thus, the ASME derating factors are in need of review.

The goal of this project is to develop an understanding of available information, identify the range of line pipe steel grades that may be affected, identify the potential impacts to ASME pipeline and piping design standards, and make recommendations for further study or experimental investigation as necessary.