Blast Wave Characteristics and Equivalency

The characteristics of blast waves generated by detonation of gas clouds are studies theoretically and validated by both small-scale and large-scale experiments with ethylene-air mixtures of different equivalence ratio. The mixtures were confined in hemispherical or spherical balloons made from thin polyethylene foils of 0.75 m³ and 15 m³ in volume. The detonation of gas mixtures was initiated by a solid explosive. The characteristics of the blast wave in terms of overpressure, impulse and duration of the positive phase obtained in this study were compared with those obtained in author's previous work and with the principal results available in the literature. This comparison made it possible to raise the significant problem of the definition of equivalent TNT according to the scale at which the tests are carried out and according to the characteristics parameters of the blast wave. The sensitivity of equivalent TNT with respect to the reduced distance was clearly shown.