In this paper the strength and sealing performance of a gasketed bolted flanged pipe joint is studied under bolt up and combined operating conditions using 3D nonlinear finite element analysis. The key combinations of internal pressure, axial and thermal loading are considered. The strength of the joint is seen to be affected by the axial and thermal loading combination whereas the joint sealing is seen to be dependent on the bolt up strategy during assembly and is slightly affected under pressure but only partially affected under axial loading in certain locations. Thermal loading was also considered and was found to have a significant effect on the sealing performance up to 100 o C, but beyond that no sealing was observed, resulting in the possibility of leakage and hence increasing the risk of overall joint failure. Finally, the joint load capacities are determined under various combined loadings showing its safe and unsafe operational limits.