Patent ID: 11935381
Assignee: NEC CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 3:
4. A fire detection system comprises:
one or more sensors installed in an optical fiber and that when detecting a location at which vibration occurred in the optical fiber, transmit first information indicating the location;
a plurality of gas state detectors that each detect a first concentration of a first gas and a second concentration of a second gas at a corresponding monitored location, and transmits second information indicating the first concentration and the second concentration and third information indicating the corresponding monitored location; and
a computer which receives the first, second, and third information and outputs fourth information indicating a sign of a fire outbreak occurred at the location when the location indicated by the received first information is within the corresponding monitored location indicated by the received third information and when a pattern of changes in a ratio of the first concentration to the second concentration at the corresponding monitored location matches a predetermined pattern.