In the current study, a Large Eddy Simulation strategy is applied to model the dispersion of compressible turbulent hydrogen jets issuing from realistic pipe geometries. The work is novel, as it explores the effect of jet densities and Reynolds numbers on vertical buoyant jets, as they emerge from the outer wall of a pipe, through a round orifice, perpendicular to the mean flow within the pipe. An efficient Godunov solver is used, and coupled with Adaptive Mesh Refinement to provide high resolution solutions only in areas of interest. The numerical results are validated against physical experiments of air and helium, which allows a degree of confidence in analysing the data obtained for hydrogen releases. The results show that the jets investigated are always asymmetric. Thus, significant discrepancies exist when applying conventional round jet assumptions to determine statistical properties associated with gas leaks from pipelines.