Page 466 - Pipelines and Risers
P. 466
433
Chapter 23
Piping Systems
23.1 Introduction
The purpose of this chapter is to present how to conduct sizing and detailed analysis of piping
system and tee piece to be consistent with the applicable pressure rating and boundary forces
determined through the pipeline operational and installation analysis.
This includes:
Selection of the Tee piece geometry dimensions;
0 Create a 3-D solid finite element model of the Tee piece;
0 Perform detailed stress analysis of the Tee under various loading conditions;
0 Document the adequacy of the Tee piece ShUcM strength to sustain the loads &om
installation, pressure test and operation.
23.2 Design Criteria
23.2.1 General
The BS5500 lays down rules for classifying the total stress calculated in the structure into various
components, which are given different allowable stress levels. However, the BS5500 does not give
any aHowable stress level for peak stress, only for membrane stress in combination with local
bending stress.
The BS5500 code considers the permissible stress in terms of the nominal design strength, f.
According to Section 3.2 in Appendix K of the code, r is taken as the lowest of either the yield
stress divided by 1.5 or the ultimate tensile stress divided by 2.35. For material WHY 65, the
design stress, f, is 226 MPa, based upon ultimate tensile strength.
