A. Introduction

Section 410, Section 419J, and Section 423I deal with various methods of nozzle reinforcement for pressure conditions. Section 419J also makes reference to British Standard 5500 (British Standards Institution, 1991) as the only code giving design rules for external loads on nozzles, and Section 404C briefly discusses the analytical basis. (However, many designers have also used the guidance given in Welding Research Council Bulletin 107 (K.R. Wichman et al., 1965) to establish stresses arising from nozzle loads).

Local loads on nozzles can arise from dead weight, pressure and thermal effects, and the geometry of the attached piping system. Loads may be normal or tangential to the shell, and bending and/or twisting moments may also be present.

In the following the scope of the approach in BS 5500 is reviewed, followed by a design example covering calculations for one of the nozzles of the heat exchanger described in Section 423 subject to arbitrary forces and moments. Symbols, nomenclature, etc. are in accordance with BS 5500 and are not defined in the text. Reference should be made to BS 5500, which must be available when studying this section.

B. Cylindrical shells