Abstract: A fire suppression system including a housing for receiving particulate matter and defining an inlet opening and an outlet opening, an input duct connected to the inlet opening, an air mover for forcing air through the input duct into the housing and out of the outlet openings, and filter means disposed in the housing and sealed between the inlet opening and the outlet opening so as to remove in the housing the particulate matter entrained by air entering through the inlet opening. Also included are an inlet sensor providing an inlet output signal dependent on the inlet temperature of combined gas and particulate matter entering the housing through the inlet opening, an outlet sensor providing a discharge output signal dependent on the outlet temperature of air discharged through the outlet opening, and a difference circuit receiving the inlet and discharge output signals and providing a difference signal in response to a predetermined minimum difference therebetween.