Accidental gas explosions in industrial equipment are seldom initiated at atmospheric conditions. Furthermore, fuel-air mixtures are generally turbulent due to rotating parts or flows. Despite these considerations, few studies have been devoted to the analysis of explosion properties at conditions of temperature and pressure different from ambient and in the presence of turbulence; therefore, experiments are still needed, even at lab-scale, e.g. for the design of mitigation system as venting devices. In this work, experimental explosion tests have been performed in 51, cylindrical tank reactor with stoichiometric methane-air mixtures at initial pressure and temperature up to 600 kPa and 400 K, centrally ignited or top ignited, and with the effect of initial turbulence level by varying the velocity of the mechanical stirrer. (C) 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.