The definition of equipment connections for pipe/flexibility analysis can be a challenge for many design engineers. Some typical assumptions can be extremely conservative. There are some established design methods for steel tanks which are based on the assumptions of typical homogeneous materials. Due to the varied shell construction of FRP these established design methods are not readily applicable for FRP tanks. We will investigate modification of these design methods for FRP tanks. Generally accepted conservative assumptions for stiffness of equipment connections will be compared to calculated shell stiffness for steel tank nozzle connections using the established design methods and compared to a modified approach supported by finite element analysis for FRP tanks nozzle connections. Comparative data will be discussed to gain a better understanding and prediction of FRP nozzle stiffness.