Abstract: Early fire detection and extinguishment is provided by a plurality of fire etection units, each associated with a localized portion of a protected space and including condition sensors specifically appropriate to the environment of that localized portion of a protected space by a selected combination of condition sensors. A fire alarm annunciator and at least one controlled fire extinguishment system portion, or a stand-alone fire extinguishment system, is provided for each fire detection unit. A central control unit preferably includes a profile detector which evaluates outputs of one or more condition sensors over time to reduce false alarm rates while increasing sensitivity to early stage fires.