Suppression of passive and active explosions has been investigated in a field-scale pipe in this paper. Water recognized effective in explosion suppression has been chosen as the extinguishing agent, and the water mist formed by home developed passive and active explosion suppressors has been proved successfully to meet the practical requirements. The experimental results showed that the suppression effects depend on the density and length of water mist suspended inside the pipe, and both passive and active explosion suppressors can fully quench the explosion of methane-air mixture with the filling of enough water. The larger the mist density and length is, the better the suppression effect becomes. For passive explosion suppression, two suppressors with different arrangements have been discussed. Moreover, a critical curve was plotted based on the experimental results of active explosion suppressions, which can be applied to evaluate the suppression effects practically. (c) 2005 Published by Elsevier Ltd.