A numerical simulation based on the method of characteristics is employed to study the dynamic response of ball valves and check valves following full bore rupture of high pressure gas pipelines. The study, performed in conjunction with the hypothetical rupture of a 145 km pipeline containing methane at 133 bar, includes simulating the effects of valve proximity to the rupture plane and the delay in closure on the total amount of inventory released prior to pipeline isolation. The accompanying pressure oscillations and surges are also accounted for. The results are in turn used to recommend guidelines regarding the appropriate choice of emergency shutdown valve depending on the failure scenario.