Abstract: The design standard of water mist spray fire extinguishing system for liquid ammonia tank area of flue gas deNOx project of thermal power plant was analyzed. It is suggested to determine the relative values clearly in the revision of the file ‘ Code for design of fire protection for fossil fuel power plants and substations ’. After the ammonia tank was added in a power plant, some new problems may be occurred in fire extinguishing water supply and drainage system, to which must pay enough attention in practical project.

Key words: flue gas deNOx, liquid ammonia tank, spray intensity, fire fighting design, drainage of extinguishing water