NOZZLE STRESSES RESULTING FROM PIPING LOADS AT LOW TYPE NOZZLES IN API 650 STORAGE TANKS

摘要

Appendix P of API 650 gives a method for determining the allowable external loads on tank shell openings. This method is based on papers by Billimoria and Hagstrom "Stiffness Coefficients and Allowable Loads for Nozzles in Flat Bottom Storage Tanks" (1977) and by Billimoria and Tarn "Experimental Investigation of Stiffness Coefficients and Allowable Loads for a Nozzle in a Flat Bottom Storage Tank" (1980). Even though this appendix is optional, industry has used it for a number of years for large diameter tanks. For tanks less than 120' (336.6 m) in diameter, this appendix is really not applicable. Inquiries and suggestions point to the fact that Appendix P sometimes results in very conservative loads, thus requiring an expensive piping system. In this paper the authors approached the problem using finite element analysis. The same tank used for physical experimentation by Billimoria and Tarn (1980) was modeled and the same loads were applied.