scope:

Stress indices and the appropriate simplified design formulas are developed for analyzing piping reducers according to the philosophy of Section I11 of the ASME Boiler and Pressure Vessel Code for Class 1 piping systems. Relatively simple equations based on extensive analytical parameter studies and related experimental data from the literature are developed for the evaluation of primary-plus-secondary and peak stresses due to internal-pressure and bending-moment loads. These simple formulas may be used directly by designers andlor incorporated into the codes and standards. Indices for primary stresses are discussed, but additional information is needed before definitive recommendations can be made. The definition, applicability, and calculation of flexibility factors for reducers subjected to bending and torsional moments are also discussed. The flexibility of reducers is then compared with the flexibility for elbows. Specific recommendations are made for incorporating the stress-index equations, definitions, and limits into the ASME Code along with a method for calculating the flexibility contribution of reducers.