Formulas are derived for stresses in the neighborhood of a circular hole in flat plate, when the opening is reinforced with a cylindrical outlet such as a pipe or nozzle.The plate is loaded in tension, either uniformly in all directions, or with transverse and longitudinal tensions in the ratio of 2:1 as is the case in cylindrical pressure vessels. Consideration is given to the possibility of balanced reinforcement by adding material on both sides of the plate.Tables and graphs are included for the use of designers who wish to find the stress-concentration factors for different combinations at plate thickness, outlet-wall thickness, and outlet diameter.