FIELD: fire-fighting. SUBSTANCE: method involves reducing oxygen content in closed room to predetermined inertial level and, in case of occurrence of fire, providing further fast reducing of oxygen content to predetermined full inertial level; using apparatus having oxygen content measuring device for measuring oxygen content in room under control, first system for generating oxygen removal gas or for extracting oxygen from room under control, second system for fast supplying of oxygen removal gas into room under control, fire detector for detecting fire signs in room air, and control unit for directing inertial reference signal to first system in accordance with oxygen content of air in room under control and for directing full inertial signal to second system in accordance with fire detecting signal delivered by fire detector. Method allows inert gas cylinders of minimal volume to be used for fire suppression. EFFECT: increased efficiency and reduced risk of suppressing fire in closed rooms. 13 cl, 1 dwg
