In the present work, a numerical study has been carried out to predict transient gas flow and pressure behaviour in a gas manifold system. The start-up and shutdown of the system, varying demands at the consumer ends, malfunctioning of compressors and valves are a few examples of common causes of transience in a gas delivery system, In particular, the sensitivity of oscillations in pressure and mass flux to variation in pipe dimensions, supply pressure and gas flow rate are,ascertained under the aforementioned, conditions of transience. The present results show that large pipe dimensions, high gas flow rate and high upstream pressure in the branch in which the disturbance is introduced, all cause greater. amplitude in mass flux and pressure oscillations in the neighboring branches. The duration of oscillations is also found to be longer. The present study has practical importance in designing as well as in operating, a gas delivery system.