In this study, a hemispherical head with pad reinforced central nozzle opening that subjected to uniform internal pressure was investigated using Finite Element Methods (FEM) to understand the design procedure. This procedure is handled according to the ASME Boiler and Pressure Vessel Code Section VIII Division 2. This standard contains two parts for the design of pressure vessels, the first part is Design by rules and the second part is Design by analysis. With reference to the ASME standard, axisymmetric finite element models for Elastic, Limit Load and Elastic-Plastic Analysis are used to demonstrate protection against plastic collapse and local failure. Maximum allowable pressures are obtained in accordance with the mentioned design methods and discussed. According to the elastic and limit load analysis methods, obtained plastic collapse results are very close. Besides, the elastic analysis method is observed to be more conservative than the Elastic-Plastic method regarding the evaluation of plastic collapse. On the other hand, for the local failure results, Elastic-Plastic Analysis is observed to be slightly conservative than the Elastic Analysis.