Abstract: The new- type dry-water fire extinguishing agent has the characteristics of high efficiency, cheap and environmental protection. It combines the advantages of aqueous fire extinguishing agent and dry powder fire extinguishing agent. It will provide more choices for dealing with the new fire scenarios emerging with the development of society. By comparing the particle size distribution and fluidity of modified ammonium sulfatedry- water powder prepared by different solid-liquid ratio, it is found that the dry-water powder prepared with 1∶13 solid-liquid ratio can meet the requirements of fire extinguishing agent well at the speed of 3 000 r/min and stirring time of 6 min. Then, the fire extinguishing experiments under different release pressure conditions were carried out. By comparing the experimental phenomena and experimental data of nine groups of experiments, it is found that the best fire extinguishing efficiency is obtained under the filling pressure of 0.6～0.7 MPa.

Key words: new-type dry-water fire extinguishing agent, preparation, fire extinguishing, release pressure