INTRODUCTION ESDU 960306 describes the nature of the lateral response to vortex shedding of structures of circular cross section. It then develops a method for calculation of this response together with the data required for its implementation. This method takes account also of the lateral response to buffeting by across-wind atmospheric turbulence components@ using the methods of ESDU 890495. Comparisons of predictions with both model and full-scale measurements and a discussion of methods of reducing the response to vortex shedding are also included in ESDU 96030. The calculation method is complex and it can realistically be implemented only through a computer program. The Program is available in three formats: (i) as FORTRAN 77 source code. (ii) as compiled executable code (for use with the ESDUview interface). (iii) as a Module to run within the Microsoft Excel* spreadsheet program. All three versions are supplied? on Disk Volume 3c in the Wind Engineering Software Volume. This Item gives guidance on running the Excel Module; use of the Fortran program and ESDUview interface is covered in Reference 9. The method can be applied for the following structure types and flow conditions: ? parallel-sided@ tapered and stepped structures@ ?circular or regular polygon cross section (8 or more sides)@ ? smooth or rough surfaces (for structures with ancillaries such as ladders attached the method applies only if the ancillary is entirely in the main structure wake)@ ? cantilevered structures and structures between end fixings@ ? vertical@ horizontal or inclined structures@ ? structures with or without strakes@ ? uniform or shear flow@ ? smooth or turbulent flow@ ? normal or yawed flow (a yawed wind affects the response only if the structure is not vertical)@ ? natural wind (full scale)@ ? simulated wind (wind tunnel)@ ? internal flows in which the structure causes a blockage of less than 10%. Example applications include stacks (chimneys) and process plant towers@ lighting standards and elements of lattice structures. Several worked examples are described in Section 3 and some guidance on sources of input data is given in Appendix A. * Microsoft and Excel are trademarks of the Microsoft Corporation ? The Fortran and ESDUview versions will be issued later.