Abstract: he inert effect and of three inert media (calcium carbonate, sodium bicarbonate and ammonium dihydrogen phosphate) and the synergistic inhibition effect between them were analyzed by 20 L-Siwek explosion test system. The results show the explosion character of aluminum powder whose concentration is 300 g/m³ is obviously inhibited after adding different inert substances, and the explosive intensity decreases with the addition of inert inhibitor; NH₄H₂PO₄ is the best of the three inert media, followed by CaCO₃. Co-inhibitory experiments indicate that the inhibition effect of composite medium is better than that of single medium. The compound inhibitor has the best anti-explosion performance when the ratio of CaCO₃  and NH₄H₂PO₄ is 1∶1.

Key words: fire, aluminum powder explosion, 20 L explosion test system, composite inert medium, explosion suppression, synergistic effect