21Measurements of the laminar and turbulent burning velocity of premixed hydrogen -air, n-22 hexane -air and n-octane -air flames were made and compared to corresponding measurements 23 of deuterium -air, n-hexane-d14 -air and n-octane-d18 -air flames performed at identical initial 24 conditions. Experiments were conducted in a constant volume, optically accessed vessel, at 25 elevated initial pressure and temperature of 0.5 MPa and 360 K, for a range of equivalence ratios.