Fire detector and tunnel disaster prevention system

Abstract

To determine signs of deterioration of fire detectors leading to non-fire alarms.SOLUTION: In a tunnel disaster prevention system, a fire detector 12 is arranged at intervals of, for example, 25 meters or 50 meters along a wall surface of a tunnel longitudinal direction includes: a fire determination unit 4810 that detects a fire based on a flame observation value by observing radiation energy emitted from a fire flame and determines a fire when a plurality of flame determination conditions based on the flame observation value are satisfied; and a deterioration symptom determination unit 4820 that determines that the fire detector is a non-flame candidate, accumulates determination results of non-flame candidates, and determines a deterioration symptom of the fire detector based on the accumulated number of the non-flame candidates accumulated in a predetermined period of time when some of the plurality of flame determination conditions are satisfied by the fire determination unit 4810 but other flame determination conditions are not satisfied.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a fire detector that detects a fire by receiving and observing radiation energy (light energy) from a detection area with a light receiving element, and a tunnel disaster prevention system that is equipped with the fire detector and monitors for abnormalities including fires. [Background technology]

[0002] Conventionally, in tunnels for expressways and the like, fire detectors are installed along the length of the tunnel as a disaster prevention system to monitor for fires that occur within the tunnel and protect people and vehicles from fire accidents, and the fire detectors are connected to signal lines pulled out from a disaster prevention receiving panel.

[0003] The fire detectors have detection areas on both the left and right sides of the longitudinal direction of the tunnel, and are placed consecutively, for example at intervals of 25 m or 50 m, so that the detection areas of adjacent fire detectors overlap in a mutually complementary manner.

[0004] In order to detect fires, fire detectors use a light receiving element to receive, for example, infrared energy as radiation energy (light energy) from fire flames occurring inside the tunnel through a translucent window, and in order to maintain the fire detection function, sensitivity tests are conducted to monitor the sensitivity of the light receiving element, and dirt tests are conducted to monitor dirt on the translucent window.

[0005] In the sensitivity test of the light receiving element, when a test signal transmitted from the disaster prevention receiving panel periodically or during a manual test is received, a test light equivalent to the light emitted from a fire flame is incident from a test light source on the light receiving element to detect the light receiving sensitivity (light receiving value).Then, the fire detector transmits a response signal of sensor failure (sensitivity abnormality) to the disaster prevention receiving panel based on the detected light receiving sensitivity, causing it to output a sensor failure alarm (sensitivity abnormality alarm).

[0006] In the dirt test of the light-transmitting window, when a test signal transmitted from the disaster prevention receiving panel during a periodic or manual test is received, a test light is incident on the light receiving element from a test light source provided outside the fire detector through the light-transmitting window to determine the light attenuation rate. If the light attenuation rate is equal to or greater than a first predetermined dirt threshold and less than a second predetermined dirt threshold, the fire detector maintains the fire detection function by correcting the received light value, and transmits a response signal for warning of abnormal dirt to the disaster prevention receiving panel to output a dirt warning alarm. If the light attenuation rate is equal to or greater than the second predetermined dirt threshold, the fire detector transmits a response signal for abnormal dirt to the disaster prevention receiving panel to output a dirt warning alarm.

[0007] Also, in recent years, methods of monitoring the deterioration of fire detectors have become known, such as a radiation type fire detector that performs a sensitivity test and judges that there is an abnormality in deterioration when the light receiving element meets the conditions before it is deemed to have failed (Patent Document 1), and a tunnel disaster prevention system that detects deterioration of a fire detector based on information (e.g., current consumption) other than the light receiving sensitivity (light receiving value) of the sensitivity test in the fire detector (Patent Document 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 3240586 [Patent Document 2] Patent No. 6900206 Summary of the Invention

[0009] However, the radiant fire detector of Patent Document 1 is effective in detecting deterioration that leads to the detector no longer detecting fires, and the tunnel disaster prevention system of Patent Document 2 is suitable for detecting deterioration of each functional part of the fire detector, but both have limited effectiveness in detecting deterioration of the fire detector that leads to false fire alarms, where the detector detects a fire when there is no fire.

[0010] An object of the present invention is to provide a fire detector that determines signs of deterioration of a fire detector that may lead to a non-fire alarm, and a tunnel disaster prevention system equipped with the fire detector. [Means for solving the problem]

[0011] (Fire detector) The present invention provides a fire detector that detects a fire based on a flame observation value obtained by observing radiation energy radiated from a fire flame, a fire determination unit that determines that a fire has occurred when a plurality of flame determination conditions based on a flame observation value are satisfied; a deterioration sign determination unit that determines a non-flame candidate when a part of a plurality of flame determination conditions is satisfied by the fire determination unit but other flame determination conditions are not satisfied, and determines a deterioration sign of the fire detector based on the non-flame candidate determination result; The present invention is characterized in that:

[0012] (Determination using frequency analysis) The fire determination unit determines that one of a plurality of flame determination conditions is satisfied when a frequency analysis result of the flame observation value or a value based on the flame observation value satisfies a predetermined determination condition, The deterioration sign determining unit determines that the component is not a flame candidate based on the frequency analysis when the frequency analysis result does not satisfy a predetermined determination condition.

[0013] (Accumulation of non-flame candidate judgements) The deterioration sign determination unit determines whether there is a deterioration sign of the fire detector when the number of times that non-flame candidates have been determined based on the frequency analysis satisfies a predetermined accumulation condition within a predetermined period of time.

[0014] (Frequency analysis using fast Fourier transform) As a predetermined judgment condition for the frequency analysis result, it is judged whether the frequency analysis result obtained by performing a fast Fourier transform on the flame observation value or a value based on the flame observation value includes a frequency distribution specific to the flame; When the frequency analysis result obtained by fast Fourier transform contains a frequency distribution specific to a flame, it is determined that the frequency analysis result of the flame observation value or the value based on the flame observation value satisfies a predetermined judgment condition.

[0015] (Prevention of erroneous judgment of signs of deterioration due to erroneous judgment factors) When the deterioration sign determination unit determines that a candidate is not a flame candidate based on frequency analysis, it determines whether the determination is an erroneous determination due to a specified erroneous determination factor, and if it determines that the determination is an erroneous determination due to a specified erroneous determination factor, it does not add to the number of times that a candidate is determined to be not a flame candidate based on frequency analysis.

[0016] (Method of preventing erroneous judgment of deterioration signs due to external vibrations, radiated noise, etc.) The fire detector monitors fires in multiple detection areas by observing different detection areas separately, The deterioration sign determination unit is A non-flame candidate determined based on frequency analysis in a specified detection area is stored as a single non-flame candidate, and a non-flame candidate determined based on frequency analysis in another detection area within a specified period is stored as a simultaneous non-flame candidate; Whether or not an erroneous determination is due to a predetermined erroneous determination factor is determined based on the ratio of the accumulated number of times of single non-flame candidates to the accumulated number of times of simultaneous non-flame candidates.

[0017] (External signal output) When the fire determination unit determines that there is a fire, it outputs a fire detection signal to the outside, and when the deterioration sign determination unit determines that there is a sign of deterioration in the fire detector, it is possible to output a deterioration sign signal to the outside.

[0018] (Continued assessment of signs of deterioration and fire assessment) When the deterioration sign determination unit determines that there is a deterioration sign of the fire detector, the fire determination unit continues the fire determination process without stopping.

[0019] (Tunnel disaster prevention system) The present invention is a tunnel disaster prevention system, characterized in that the above-mentioned fire detectors are installed at predetermined intervals along the longitudinal direction of a tunnel and the fire detectors are connected to a disaster prevention receiving panel. Effect of the Invention

[0020] (Effects of fire detectors) The present invention is a fire detector that detects a fire based on flame observation values ​​obtained by observing radiation energy emitted from a fire flame, and is provided with a fire judgment unit that judges a fire to be a fire when a plurality of flame judgment conditions based on the flame observation values ​​are satisfied, and a deterioration sign judgment unit that judges a fire to be a non-flame candidate when the fire judgment unit satisfies some of the plurality of flame judgment conditions but not others, and judges signs of deterioration of the fire detector based on the non-flame candidate judgment result.Therefore, it is possible to know the signs of deterioration, which are a precursor to deterioration, before a non-fire alarm is issued due to a false detection of a fire by the fire detector caused by deterioration abnormality, and it is possible to take necessary measures for a fire detector that has been judged to have signs of deterioration, such as preparing a replacement fire detector or making appropriate schedules for replacement work, and it is possible to maintain the reliability of fire detection even as the fire detector deteriorates over time.

[0021] In addition, by setting the conditions for determining whether a deterioration is a sign of deterioration as occurring when some of the flame determination conditions for detecting a fire are satisfied but other flame determination conditions are not satisfied, this system is effective in preventing deterioration of fire detectors that leads to non-fire alarms.

[0022] (Effect of Judgment Using Frequency Analysis) In addition, the fire judgment unit judges that one of a plurality of flame judgment conditions is satisfied when the frequency analysis result of the flame observation value or a value based on the flame observation value satisfies a specified judgment condition, and the deterioration sign judgment unit judges that it is a non-flame candidate based on the frequency analysis when the frequency analysis result does not satisfy the specified judgment condition, thereby making it possible to further improve the accuracy of judgment of fire and non-fire candidates.

[0023] (Effect of accumulating judgments of non-flame candidates) In addition, the deterioration sign determination unit is configured to determine signs of deterioration in the fire detector when the number of non-flame candidate determinations based on frequency analysis satisfies a specified accumulation condition within a specified period of time, thereby making it possible to further improve the accuracy of determining signs of deterioration in the fire detector.

[0024] (Effect of preventing erroneous judgment of deterioration signs due to erroneous judgment factors) In addition, when the deterioration sign judgment unit judges that a fire is a non-flame candidate based on frequency analysis, it judges whether the judgment is an erroneous judgment due to a specified erroneous judgment factor, and if it judges that the judgment is an erroneous judgment due to a specified erroneous judgment factor, it does not add to the number of times that non-flame candidates have been judged based on frequency analysis. More specifically, the fire detector monitors fires in multiple detection areas by individually observing different detection areas, and the deterioration sign judgment unit accumulates non-flame candidates judged based on frequency analysis in a specified detection area as single non-flame candidates, and if a non-flame candidate is judged based on frequency analysis in another detection area within a specified period, it accumulates them as simultaneous non-flame candidates, and judges whether the erroneous judgment is due to a specified erroneous judgment factor based on the ratio of the accumulated number of single non-flame candidates to the accumulated number of simultaneous non-flame candidates. Therefore, it is possible to remove the effects of erroneous judgment factors that are not deterioration of the fire detector but that may be judged and accumulated as a sign of deterioration of the fire detector, such as external vibrations and radiated noise, from the judgment of signs of deterioration, making it possible to further improve the accuracy of judgment of signs of deterioration.

[0025] (Effect of external signal output) In addition, if the fire determination unit determines that there is a fire, a fire detection signal is output to the outside, and if the deterioration sign determination unit determines that there is a sign of deterioration in the fire detector, a deterioration sign signal can be output to the outside, making it possible to communicate necessary information to the outside of the fire detector.

[0026] (Effects of continuing to assess signs of deterioration and fire assessments) In addition, when the deterioration sign determination unit determines that there is a sign of deterioration in the fire detector, the fire determination process by the fire determination unit is continued without being stopped.Therefore, when it is determined that there is a sign of deterioration in the fire detector, the fire detector is in a state of deterioration signs, which is a precursor to deterioration, and no deterioration abnormality has occurred, and there is no abnormality in the current fire detection function, so fire detection continues without being stopped, making it possible to maintain fire detection. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is an explanatory diagram showing a tunnel disaster prevention system. [Diagram 2]FIG. 2 is an explanatory diagram showing the functional configuration of a disaster prevention receiving panel. [Diagram 3] FIG. 2 is an explanatory diagram showing the appearance of a fire detector. [Figure 4] FIG. 2 is an explanatory diagram showing the functional configuration of a fire detector. [Diagram 5] FIG. 13 is an explanatory diagram showing an embodiment of a light receiving processing section of a three-wavelength system. [Figure 6] 4 is an explanatory diagram showing a signal waveform of a light receiving signal outputted by observing a combustion flame. FIG. [Figure 7] FIG. 4 is an explanatory diagram showing a frequency distribution of a received light signal outputted by observing a combustion flame. [Figure 8] 4 is a flowchart showing a processing operation of a fire detector. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a fire detector and a tunnel disaster prevention system according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following preferred embodiments.

[0029] [Basic Concept of the Embodiment] First, the basic concept of the embodiment will be described. The embodiment generally relates to a fire detector that detects a fire based on a flame observation value obtained by observing radiation energy emitted from a fire flame, and another embodiment includes a tunnel disaster prevention system equipped with the fire detector.

[0030] Here, the "flame observation value" is obtained by a fire detector receiving and observing the radiation energy (light energy) emitted from a flame, for example, radiation energy (infrared energy) in the wavelength band with a central wavelength of 4.5 μm due to resonance radiation of CO2 from a combustion flame, and includes, for example, the light receiving value (light receiving sensitivity) obtained by converting the observed radiation energy (light signal) into an electrical signal.

[0031] In addition, fire detectors may include those that obtain non-fire observation values ​​in addition to flame observation values, where "non-flame observation values" are values ​​that are not radiation energy (light energy) emitted from a flame, such as radiation energy (infrared energy) in the wavelength band with a central wavelength of 5.0 μm, which is on the longer wavelength side of the radiation energy in the wavelength band with a central wavelength of 4.5 μm, or radiation energy (infrared energy) in the wavelength band with a central wavelength of 2.3 μm, which is on the shorter wavelength side, and include light receiving values ​​(light receiving sensitivity) in which the observed radiation energy (light signal) is converted into an electrical signal, similar to flame observation values.

[0032] For example, a method in which flame observation values ​​are obtained from radiation energy in a wavelength band with a central wavelength of 4.5 μm and non-flame observation values ​​are obtained from radiation energy in a wavelength band of 5.0 μm to determine whether a fire has occurred is called a two-wavelength method, and in addition, a method in which non-fire observation values ​​are obtained from radiation energy in a wavelength band of 2.3 μm to determine whether a fire has occurred is called a three-wavelength method, and non-flame observation values ​​are not necessarily limited to radiation energy in one wavelength band.

[0033] Also, a "disaster prevention system" is a system for monitoring and preventing / dealing with abnormalities such as fires that may occur in the monitored area, and is a concept that includes those that naturally include components other than fire detectors and those that monitor abnormalities other than fires. For example, it includes a system that includes, as components other than fire detectors, an imaging unit that captures images of the monitored area, a disaster prevention receiving panel that receives signals from fire detectors and outputs corresponding alarms, and a system that monitors people (suspicious people), vehicles, gas leaks, etc. as abnormalities other than fires. A disaster prevention system installed in a tunnel (tunnel disaster prevention system) includes a system in which fire detectors are installed at regular intervals along the length of the tunnel and the fire detectors are connected to a disaster prevention receiving panel.

[0034] The fire detector of the embodiment includes a fire determination unit and a deterioration sign determination unit.

[0035] Here, the "fire determination unit" determines that there is a fire when multiple flame determination conditions based on flame observation values ​​are met, and the "deterioration prediction determination unit" determines that there is a non-flame candidate when the fire determination unit satisfies some of the multiple flame determination conditions but not others, and determines the signs of deterioration of the fire detector based on the non-flame candidate determination result.

[0036] In other words, if all of the multiple flame determination conditions are met, the fire detector will determine that there is a fire using the fire determination unit, and if some of the multiple flame determination conditions are not met, it will determine that there is a non-flame candidate and monitor for signs of deterioration, which is a precursor to the fire detector deteriorating and becoming abnormal, leading to a non-fire alarm.

[0037] In addition, the flame judgment conditions in the "fire judgment unit" may include any judgment conditions, but for example, the frequency analysis results of the flame observation values ​​or values ​​based on the flame observation values ​​may include predetermined judgment conditions, and if the judgment conditions based on the frequency analysis are satisfied, the fire judgment unit judges that one of the multiple flame judgment conditions is satisfied, and if the judgment conditions based on the frequency analysis are not satisfied, the deterioration sign judgment unit judges that it is a non-flame candidate based on the frequency analysis.

[0038] Furthermore, as a "frequency analysis", for example, a fast Fourier transform is used, and it is determined whether the frequency analysis result obtained by fast Fourier transforming the flame observation value or a value based on the flame observation value includes a frequency distribution specific to a flame, and if the frequency analysis result includes a frequency distribution specific to a flame, it is determined that the frequency analysis result of the flame observation value or the value based on the flame observation value satisfies a predetermined determination condition. Here, the "frequency distribution specific to a flame" includes, for example, a distribution of fluctuation frequencies existing near a specific frequency specific to a flame. Furthermore, the "value based on the flame observation value" is obtained by performing a predetermined process on the acquired flame observation value, and includes, for example, a value obtained by performing an addition process of adding flame observation values ​​acquired by multiple sensors (added flame observation value described later), etc.

[0039] In addition, the deterioration sign determination unit determines signs of deterioration of the fire detector when the number of times non-flame candidate determinations based on frequency analysis satisfy a specified accumulation condition within a specified period of time; the ``specified accumulation condition'' is, for example, a condition for determining whether the number of times non-flame candidate determinations have reached a set specified accumulation number, and includes the condition of determining that the specified accumulation condition is satisfied when the specified accumulation number has been reached.

[0040] In addition, in order to prevent erroneous judgment of signs of deterioration due to erroneous judgment factors, when the "deterioration sign judgment unit" judges a non-flame candidate based on frequency analysis, it judges whether the judgment is an erroneous judgment due to a specified erroneous judgment factor, and if it judges that the judgment is an erroneous judgment due to a specified erroneous judgment factor, it does not add it to the number of times that a non-flame candidate was judged based on frequency analysis. Note that an "erroneous judgment factor" is a factor that is not a factor that causes signs of deterioration in a fire detector, but may be judged as a non-flame candidate based on the results of frequency analysis of a flame observation value or a value based on a flame observation value caused by an erroneous judgment factor.

[0041] For example, in a disaster prevention system installed in a tunnel, when a fire detector is subjected to strong vibrations due to the passage of a large vehicle or the like, the pyroelectric element used as the light receiving element observing the radiation energy of the fire flame also functions as a piezoelectric element, so the deterioration sign determination unit may determine deterioration signs due to the influence of external vibrations as a cause of erroneous determination, and this is to eliminate erroneous determination of deterioration signs caused by external vibrations as a cause of erroneous determination.It is also possible to eliminate erroneous determination of deterioration signs caused by other causes such as radiation noise.

[0042] In order to prevent erroneous judgment of signs of deterioration due to erroneous judgment factors, for example, the deterioration sign judgment unit accumulates non-flame candidates determined based on frequency analysis in a specified detection area as single non-flame candidates, and if a non-flame candidate is determined based on frequency analysis in another detection area within a specified period of time, it accumulates it as a simultaneous non-flame candidate, and judges whether the erroneous judgment is due to an erroneous judgment factor based on the ratio of the accumulated number of single non-flame candidates to the accumulated number of simultaneous non-flame candidates.

[0043] Here, the "detection area" refers to the field of view within which the fire detector can observe radiation energy, and "individually observing different detection areas" means that the fire detectors have different field of view, and each fire detector is equipped with an independent fire detection unit corresponding to its detection area.

[0044] In addition, an "individual non-fire candidate" is determined based on the observation value corresponding to one detection area, while a "simultaneous non-fire candidate" is determined based on the observation value corresponding to multiple detection areas. If deterioration or signs of deterioration appear in a fire detection unit corresponding to one detection area, it will affect that fire detection unit, but since the majority of erroneous judgment factors such as external vibrations affect the entire fire detector regardless of the detection area, by determining "individual non-fire candidate" and "simultaneous non-fire candidate", erroneous judgments due to erroneous judgment factors can be eliminated.

[0045] Incidentally, there are a number of judgment conditions that have a "predetermined period" as a condition, but the "predetermined period" is a period that is set individually for each judgment condition, and does not mean that all the predetermined periods are the same period, but is appropriately set for each judgment condition taking into consideration the design concept, etc. Incidentally, as a result of appropriately setting each "predetermined period," it is possible that the predetermined periods for different judgment conditions are the same period.

[0046] In addition, the fire detector can output a fire detection signal to the outside when the fire determination unit determines that there is a fire, and can output a deterioration sign signal to the outside after the deterioration sign determination unit determines that there is a deterioration sign of the fire detector. Therefore, the deterioration sign signal can be transmitted to the outside, such as a disaster prevention receiving panel, at any timing, for example, when responding to a call signal from the outside or when the fire detector makes a determination, thereby enabling the necessary processing as a disaster prevention system.

[0047] Furthermore, when the deterioration sign determination section determines that there is a deterioration sign of the fire detector, the fire determination section continues the fire determination process without stopping it.

[0048] A specific embodiment will be described below. The specific embodiment shown below targets a "tunnel disaster prevention system" in which fire detectors are installed at predetermined intervals along the length of a tunnel and connected to a disaster prevention receiving panel, and the fire detector is a "three-wavelength type that observes radiation energy in the 4.5 μm wavelength band to obtain a flame observation value, and observes radiation energy in the 5.0 μm and 2.3 μm wavelength bands to obtain a non-flame observation value to determine whether a fire has occurred."

[0049] [Specific details of the embodiment] The embodiment of the fire detector will now be described in more detail, which will be divided into the following sections: a. Tunnel disaster prevention system b. Disaster prevention receiving panel c. Fire detector c1. Appearance of the fire detector c2. Functional configuration of fire detector d. Light receiving processing section d1.4.5μm light receiving processing part d2.5.0μm light receiving processing section d3.2.3μm light receiving processing section e.Fire judgment department e1. Identification of the first flame candidate e2. Identification of the second flame candidate f. Deterioration sign determination unit f1. Judging the first non-flame candidate f2. Judgment of the second non-flame candidate f3. Identifying signs of deterioration f4. Prevention of false detection of signs of deterioration due to external vibration g. Test control section h. Fire detector processing operation h1. Fire detection operation h2.Deterioration sign judgment operation i. Operation of the disaster prevention receiving panel j. Modifications of the present invention

[0050] [a.Tunnel disaster prevention system] First, the tunnel disaster prevention system will be described with reference to Fig. 1 showing the tunnel disaster prevention system.

[0051] As shown in Fig. 1, an up-line tunnel 1a and an out-line tunnel 1b are constructed as tunnels for a motorway. Inside the up-line tunnel 1a and the out-line tunnel 1b, fire detectors 12 are installed at intervals of, for example, 25 meters or 50 meters along the walls in the longitudinal direction of the tunnel.

[0052] The fire detector 12 is equipped with two sets of fire detection units that set detection areas on both the left and right sides of the tunnel in the longitudinal direction and individually monitor either the left or right detection area. The fire detectors are arranged continuously so that the detection areas of the adjacent fire detectors overlap in a mutually complementary manner, and detect fires by observing, for example, infrared energy as radiation energy (light energy) from flames caused by a fire that has broken out within the detection area, and have the function of transmitting a fire detection signal to the outside when a fire is detected.

[0053] In addition, when the fire detector 12 determines that the fire is not a fire candidate during the fire detection process, it has the function of determining whether the fire detector is showing signs of deterioration based on the non-fire candidate determination result, and if it determines that the fire detector is showing signs of deterioration, it has the function of transmitting a deterioration sign determination signal to the outside.

[0054] In addition, as part of a disaster prevention system, the up-bound tunnel 1a and the down-bound tunnel 1b are provided with manual reporting devices and emergency telephones for reporting fires, fire hydrant devices for extinguishing fires and preventing the spread of fires, and water sprayers that spray fire water from water spray heads to protect the tunnel structure and inside the ducts from fires, but these are not shown in the illustration.

[0055] Transmission lines 14a, 14b including a power line and a signal line are drawn from the disaster prevention receiving panel 10 to the up line tunnel 1a and the down line tunnel 1b, and the transmission lines 14a, 14b are connected to fire detectors 12. The tunnel disaster prevention system is an R-type (Record-type) disaster prevention system in which a unique address is set for each line of the fire detectors 12. When there is no need to distinguish between the transmission lines 14a, 14b, they may be called the transmission line 14.

[0056] In addition, the disaster prevention receiving panel 10 is provided with a fire pump equipment 16, duct cooling pump equipment 18, IG slave station equipment 20, ventilation equipment 22, alarm display board equipment 24, radio rebroadcast equipment 26, television monitoring equipment 28, lighting equipment 30, etc., and except for the IG slave station equipment 20 which is connected by a data transmission line, the other equipment is individually connected to the disaster prevention receiving panel 10 by P-type signal lines. Here, the IG slave station equipment 20 is a communication equipment which connects the disaster prevention receiving panel 10 and remote monitoring and control equipment 32, which is a higher-level equipment provided externally, via a network.

[0057] The ventilation equipment 22 is a facility that gives energy to the air in the tunnel by blowing out a high wind speed from a jet fan installed on the ceiling side of the tunnel, creating a ventilation flow in the longitudinal direction of the tunnel. The alarm display board equipment 24 is a facility that notifies users in the tunnel of abnormalities inside the tunnel by displaying them on an electronic display board. The radio rebroadcast equipment 26 is a facility that enables drivers and others in the tunnel to receive information from the road administrator. The television monitoring equipment 28 is a facility for understanding the situation inside the tunnel when confirming the scale and location of a fire, activating the water spray equipment, and providing evacuation guidance. The lighting equipment 30 is a facility that drives and manages the lighting equipment in the tunnel.

[0058] [b. Disaster prevention receiving panel] Next, the disaster prevention receiving panel will be explained with reference to Fig. 2 showing the functional configuration of the disaster prevention receiving panel.

[0059] 2, the disaster prevention receiving panel 10 includes a panel control unit 34. The panel control unit 34 has a function realized by, for example, executing a program, and uses, as hardware, a computer circuit including a CPU, a memory, various input / output ports, and the like.

[0060] Transmission units 36a, 36b are provided for the panel control unit 34, and a plurality of fire detectors 12 are connected to transmission lines 14a, 14b drawn from the transmission units 36a, 36b, respectively. When the transmission lines 36a, 36b are not to be distinguished from each other, they may be referred to as the transmission unit 36.

[0061] In addition, the panel control unit 34 is provided with an alarm unit 38 equipped with a speaker, alarm indicator lights, etc., a display unit 40 equipped with an LCD display, a printer, etc., an operation unit 42 equipped with various switches, etc., and a modem 44 connecting the IG child station equipment 20 which communicates with external monitoring equipment, and further with an IO unit 46 connecting the fire pump equipment 16, cooling pump equipment 18, ventilation equipment 22, alarm display board equipment 24, radio rebroadcast equipment 26, television monitoring equipment 28 and lighting equipment 30 shown in Figure 1.

[0062] The panel control unit 34 instructs the transmission units 36a, 36b to repeatedly send a call signal including a polling command that sequentially specifies the addresses of the fire detectors 12, and when the fire detector 12 receives a call signal that matches its own address, it replies with a response signal including its own status information, such as fire detection and test results.

[0063] In addition, when the panel control unit 34 detects a fire by receiving a response signal from the fire detector 12, it controls the alarm unit 38 to output a fire alarm and also instructs the IO unit 46 to control the linkage of other equipment.

[0064] Furthermore, when the system is started up or at predetermined intervals during operation, the panel control unit 34 transmits a test signal containing a test instruction command sequentially specifying the addresses of the fire detectors 12, controls the fire detectors 12 to perform tests such as sensitivity tests, dirt tests, and deterioration tests, and controls the fire detectors 12 to return the results of each test as a response signal. It is also possible to transmit a test signal to an individual fire detector to perform a test by performing a test operation specifying the address of a specific fire detector 12 using the operation unit 42.

[0065] In addition, when the panel control unit 34 receives a response signal of a sensor failure (sensitivity abnormality) obtained by a sensitivity test of the fire detector 12, it controls the display unit 40 to issue a sensor failure alarm (sensitivity abnormality alarm) specifying the address of the fire detector, for example, by an alarm sound, a display, or printing.

[0066] In addition, when the panel control unit 34 receives a response signal of a contamination abnormality warning obtained by a contamination test of the fire detector 12, it controls the display unit 40 to issue a contamination abnormality warning alarm specifying the address of the fire detector, for example, by an alarm sound, a display display, or printing.

[0067] In addition, when the panel control unit 34 receives a response signal indicating a contamination abnormality obtained by a contamination test of the fire detector 12, it controls the display unit 40 to issue a contamination alarm specifying the address of the fire detector, for example, by an alarm sound, a display display, or printing.

[0068] In addition, when the panel control unit 34 receives a deterioration response signal obtained by a deterioration test of the fire detector 12, it controls the display unit 40 to issue a deterioration alarm specifying the address of the fire detector, for example, by an alarm sound, a display, or printing.

[0069] In addition, when the panel control unit 34 receives a deterioration sign determination signal transmitted by the fire detector 12 after determining signs of deterioration, it controls the display unit 40 to issue an alarm of the deterioration signs specifying the address of the fire detector, for example by sounding an alarm, displaying a display, or printing.

[0070] In addition, when the panel control unit 34 receives a warning, abnormality or deterioration response signal obtained from the sensitivity test, dirt test and deterioration test of the fire detector 12, or a deterioration sign determination signal sent by the fire detector 12 after determining a deterioration sign, it transmits the signal from the modem 44 to the remote monitoring and control equipment 32 via the IG substation equipment 20 shown in Figure 1, and controls the remote monitoring and control equipment 32 to similarly issue an alarm of warning, abnormality, deterioration sign or deterioration.

[0071] Furthermore, the panel control unit 34 performs control to change threshold values ​​and the like that serve as judgment conditions for determining sensitivity abnormalities, including advance notice or signs, contamination abnormalities, and deterioration that are set in the fire detector 12, based on operations of the operation unit 42 that utilizes the display of the display unit 40. The control to change the threshold values ​​and the like that serve as judgment conditions can be performed to simultaneously change the judgment conditions of all fire detectors 12 connected to the transmission line 14, or to change the judgment conditions of a specific fire detector 12 by specifying an address.

[0072] [c. Fire detector] Next, the fire detector will be described with reference to Fig. 3 showing the external appearance of the fire detector and Fig. 4 showing the functional configuration of the fire detector.

[0073] 3, the X, Y and Z directions are mutually orthogonal, and specifically, when looking at the front surface on which the light-transmitting window is provided, the X direction is the left-right direction, the Y direction is the up-down direction, and the Z direction is the front-back direction. Also, the +X side in the X direction is the right side, the -X side is the left side, the +Y side in the Y direction is the top side, the -Y side is the bottom side, and the +Z side in the Z direction is the front side, and the -Z side is the rear side.

[0074] (c1. Appearance of the fire detector) First, the appearance of the fire detector will be described. As shown in Fig. 3, the fire detector 12 has two pairs of light-transmitting windows 80R and 80L on the front side of the housing 1210, separated into the left and right, and a light receiving element unit (sensor unit) is arranged inside the housing 1210 corresponding to the positions of the light-transmitting windows 80R and 80L. In addition, two pairs of light-transmitting windows 81R and 81L for test light sources that accommodate external test light sources used for soiling tests of the light-transmitting windows 80R and 80L are provided in positions near the light-transmitting windows 80R and 80L that allow light to be incident on the light receiving element units. In order to distinguish between the light-transmitting windows 80R and 80L, the light-transmitting window 80R may be called the right-eye light-transmitting window 80R, and the light-transmitting window 80L may be called the left-eye light-transmitting window 80L.

[0075] (c2. Functional configuration of fire detector) Next, the functional configuration of the fire detector will be described. As shown in Fig. 4, the fire detector 12 is provided with a detector control unit 48, a transmission unit 50, a power supply unit 52, a test power supply unit 54, a test light emission driving unit 56, and two sets of left and right fire detection units 60R, 60L. In order to distinguish between the fire detection units 60R, 60L, the fire detection unit 60R may be referred to as the right eye fire detection unit 60R, and the fire detection unit 60L may be referred to as the left eye fire detection unit 60L.

[0076] The right eye fire detection unit 60R is provided with two sets of light receiving element units 62R, 64R and 66R, and optical wavelength filters 74R, 76R and 78R are individually arranged on the outside of each light receiving element unit, and further, a light-transmitting window 80R made of an infrared-transmitting material such as sapphire glass is commonly arranged on the outside of each optical wavelength filter.

[0077] The structure of the light receiving element unit 62R is arbitrary, but for example, it has a pyroelectric element arranged on the surface of the substrate (the surface on the translucent window side), and is packaged by providing a cover member on the surface side of the substrate that has an optical wavelength filter 74R that selectively transmits infrared light with a center wavelength of 4.5 μm.

[0078] Here, the pyroelectric element that functions as the light receiving element of the light receiving element section 62R has the function of receiving radiation energy and converting it into an electrical signal, and also has the function of a piezoelectric element, converting the distortion suffered by the pyroelectric element due to external vibrations into an electrical signal and outputting it.

[0079] The two light receiving element units 62R receive infrared energy in a wavelength band having a central wavelength of approximately 4.5 μm that is emitted from the combustion flame in association with CO2 resonance, convert it into an electrical signal, and output it to the 4.5 μm light receiving processing unit 68R.

[0080] The light receiving element 64R has a structure similar to that of the light receiving element 62R, and receives infrared energy in a wavelength band having a central wavelength of 5.0 μm, which is longer than 4.5 μm, converts it into an electrical signal, and outputs it to the 5.0 μm light receiving processing unit 70R.

[0081] The light receiving element 66R has a structure similar to that of the light receiving element 62R, and receives infrared energy in a wavelength band having a central wavelength of 2.3 μm, which is on the shorter wavelength side of 4.5 μm, converts it into an electrical signal, and outputs it to the 2.3 μm light receiving processing unit 72R.

[0082] In addition, an internal test light source 82R used for testing the sensitivity of the light-receiving element sections is provided inside the light-transmitting window 80R corresponding to each light-receiving element section, and an external test light source 84R used for testing the dirt on the light-transmitting window is provided in common outside the light-transmitting window 80R.

[0083] The left eye fire detection unit 60L has a structure similar to that of the right eye fire detection unit 60R, and is provided with two sets of light receiving element units 62L, 64L, 66L, 4.5 μm light receiving processing unit 68L, 5.0 μm light receiving processing unit 70L, 2.3 μm light receiving processing unit 72L, an internal test light source 82L and an external test light source 84L.

[0084] The detector control unit 48 is a function realized by, for example, executing a program, and uses, as hardware, a computer circuit or the like equipped with a CPU, a memory, various input / output ports, etc. The detector control unit 48 is provided with a fire determination unit 4810, a deterioration sign determination unit 4820, and a test control unit 4830 as functions realized by executing a program.

[0085] The transmission unit 50 is connected to the transmission unit 36 ​​of the disaster prevention receiving panel 10 shown in Figure 2 via the serial transmission line SA and serial transmission common line SB of the transmission path 14, and transmits and receives various signals between the transmission unit 36 ​​of the disaster prevention receiving panel 10 via serial transmission.

[0086] The power supply unit 52 receives power from the disaster prevention receiving panel 10 shown in Figure 2 via the power line SV and power common line SC included in the transmission path 14, and supplies a predetermined power supply voltage to circuit blocks such as the detector control unit 48, the transmission unit 50, and two sets of fire detection units 60R and 60L.

[0087] The test power supply unit 54 receives power from the disaster prevention receiving panel 10 shown in Figure 2 via the power line SV and power common line SC included in the transmission path 14, supplies a predetermined power supply voltage to the test light emission driving unit 56, and drives the internal test light sources 82R, 82L and the external test light sources 84R, 84L via the test light emission driving unit 56 during sensitivity tests of the light receiving element unit and dirt tests of the translucent window.

[0088] [d. Light receiving processing section] Next, the 4.5 μm light receiving processing section, the 5.0 μm light receiving processing section, and the 2.3 μm light receiving processing section provided in the fire detection section will be described. Note that, although the light receiving processing section of the right eye fire detection section 60R will be described, the same applies to the left eye fire detection section 60L.

[0089] (d1.4.5μm light receiving processing section) First, the 4.5 μm light receiving processing section will be described. As shown in Fig. 5, the 4.5 μm light receiving processing section 68R converts infrared energy in a wavelength band with a center wavelength of 4.5 μm, which is emitted from the combustion flame in association with CO2 resonance, into electrical signals by the two sets of light receiving element sections 62R, and outputs the received light signals E0, E1, and E2 to the detector control section 48.

[0090] The 4.5 μm light receiving processing unit 68R is provided with, following the two sets of light receiving element units 62R, a pre-filter 86 that passes only signal components of a predetermined frequency band from the signal input from the light receiving element unit 62R, a pre-amplifier 88 that performs initial stage amplification of the signal components that have passed through the pre-filter 86, a main amplifier 90 that amplifies the output from the pre-amplifier 88, and a final stage amplifier 92 that amplifies the light receiving signals E01, E02 output from the pre-amplifier 90, and the light receiving signals E1, E2 (individual light receiving signals) are output from each of the final stage amplifiers 92 to the detector control unit 48, and the light receiving signals E1, E2 are digitally converted at A / D conversion ports 112, 116 of the detector control unit 48.

[0091] In addition, the 4.5 μm light receiving processing unit 68R is provided with an adder 94, and the light receiving signals E01, E02 output from the two main amplifiers 90 are added and amplified by the adder 94 and output to the detector control unit 48 as a light receiving signal E0 (added light receiving signal), and the light receiving signal E0 is converted to digital form at the A / D conversion port 114.

[0092] A / D conversion ports 112, 116 provided in detector control unit 48 digitally convert light reception signals E1, E2 at a predetermined sampling period. A / D conversion is performed at a predetermined sampling period, digitally converted digital light reception signals (4.5 μm individual flame observation values ​​D1, D2) are acquired and stored in memory, and fire determination unit 4810 acquires 4.5 μm individual flame observation values ​​ΣD1, ΣD2 by integrating the digital light reception values ​​stored in memory for a predetermined time, and holds them for use in fire determination.

[0093] Similarly, for the light reception signal E0 output from the adder 94, a digital light reception value (4.5 μm additive flame observation value D0) is acquired by the A / D conversion port 114 and stored in memory, and the 4.5 μm additive flame observation value ΣD0 is acquired by integrating the digital light reception value stored in the memory for a predetermined period of time and held for use in determining whether or not there is a fire.

[0094] Here, when infrared energy in a wavelength band with a central wavelength of 4.5 μm is received from a combustion flame, the light receiving signals E1, E2 output from the two main amplifiers 90 are, for example, as shown in Fig. 6. Fig. 6(A) and (B) show the light receiving signals E1, E2 obtained over a predetermined period, for example, two seconds, and in a normal state where the fire detector 12 is not degraded, the waveform levels of the light receiving signals E1, E2 output from each of the two processing systems are roughly the same, but when the operation period of the fire detector 12 is extended and the degree of degradation of the fire detector 12 progresses, the waveform levels of the light receiving signals E1, E2 differ, and the degree of agreement between the light receiving signals E1, E2 may decrease.

[0095] (d2.5.0μm light receiving processing section) Next, the 5.0 μm light receiving processing section will be described. The 5.0 μm light receiving processing section 70R converts infrared energy in a wavelength band having a center wavelength of 5.0 μm into an electrical signal and outputs a received light signal E3 to the detector control section 48.

[0096] The 5.0 μm light receiving processing unit 70R is provided with, following the light receiving element unit 64R, a pre-filter 96 that passes only signal components of a predetermined frequency band from the signal input from the light receiving element unit 64R, a pre-amplifier 98 that performs initial amplification of the signal components that have passed through the pre-filter 96, a main amplifier 100 that amplifies the output from the pre-amplifier 98, and a final stage amplifier 102 that amplifies the output from the main amplifier 100. A light receiving signal E3 is output from the final stage amplifier 92 to the detector control unit 48, and the light receiving signal E3 is converted into digital form at an A / D conversion port 118 of the detector control unit 48.

[0097] A / D conversion is performed on the A / D conversion port 118 at a predetermined sampling period, a digital light receiving signal (5.0 μm non-flame observation value D3) is acquired and stored in memory, and the fire detection unit 4810 acquires the 5.0 μm non-flame observation value ΣD3 by integrating the digital light receiving value stored in the memory for a predetermined time period and holds it for use in fire detection.

[0098] (d3.2.3μm light receiving processing section) The 2.3 μm light receiving processor 72R converts infrared energy in a wavelength band having a center wavelength of 2.3 μm into an electrical signal and outputs a received light signal E4 to the detector controller 48.

[0099] The 2.3 μm light receiving processing unit 72R is provided with, following the light receiving element unit 66R, a pre-filter 104 that passes only signal components of a predetermined frequency band from the light receiving signal output from the light receiving element unit 66R, a pre-amplifier 106 that performs initial amplification of the signal components that have passed through the pre-filter 104, a main amplifier 108 that amplifies the output from the pre-amplifier 106, and a final stage amplifier 110 that amplifies the output from the main amplifier 108. A light receiving signal E4 is output from the final stage amplifier 110 to the detector control unit 48, and the light receiving signal E4 is converted into digital form at an A / D conversion port 120 of the detector control unit 48.

[0100] A / D conversion is performed on the A / D conversion port 1209 at a predetermined sampling period, a digital light receiving signal (2.3 μm non-flame observation value D4) is acquired and stored in memory, and the fire detection unit 4810 acquires the 2.3 μm non-flame observation value ΣD4 by integrating the digital light receiving value stored in the memory for a predetermined time period and retains it for use in fire detection.

[0101] [e.Fire judgment department] Next, the fire determination unit 4810 provided in the detector control unit 48 will be described. The fire determination unit 4810 determines a fire using the 4.5 μm flame observation value, the 4.5 μm individual flame observation value, the 5.0 μm non-flame observation value, and the 2.3 μm non-flame observation value acquired based on the light receiving signals E0 to E4 from the 4.5 μm light receiving processing unit, the 5.0 μm light receiving processing unit, and the 2.3 μm light receiving processing unit. In the following description, the 4.5 μm added flame observation value may be referred to as the "added flame observation value", the 4.5 μm individual flame observation value as the "individual flame observation value", and the 5.0 μm non-flame observation value and the 2.3 μm non-flame observation value as the "non-flame observation value".

[0102] (e1. Determination of the first flame candidate) The fire determination processing unit 4810 stores the digital light reception values ​​for a predetermined period in memory, and repeats the process of determining a first flame candidate based on the flame observation value ΣD0, the individual flame observation values ​​ΣD1, ΣD2, the non-flame observation value ΣD3, and the non-flame observation value ΣD4 obtained by integrating the digital light reception values ​​stored in the memory. Then, a first flame candidate is determined when all of a plurality of flame determination conditions are satisfied according to the following procedure.

[0103] In the first flame candidate determination process, as a first step, it is determined whether or not the additive flame observation value ΣD0 satisfies a determination condition that the additive flame observation value ΣD0 is equal to or greater than a predetermined threshold value.

[0104] As a second step, if the conditions of the first step are satisfied, the ratio (ΣD0 / ΣD3) between the additive flame observation value ΣD0 and the non-flame observation value ΣD3 is calculated, and it is determined whether the determined ratio (ΣD0 / ΣD3) satisfies the judgment condition that it is greater than or equal to a predetermined threshold value.

[0105] As a third step, if the conditions of the second step are satisfied, the ratio (ΣD0 / ΣD4) of the additive flame observation value ΣD0 to the non-flame observation value ΣD4 is calculated, and it is determined whether the determined ratio (ΣD0 / ΣD4) satisfies the judgment condition that it is greater than or equal to a predetermined threshold value.

[0106] In the fourth step, if the conditions in the third step are met, it is determined whether the individual flame observation values ​​ΣD1 and ΣD2 meet a predetermined coincidence condition.

[0107] In the fifth step, if the fourth condition is met, the object is judged as a first flame candidate and the judgment result is stored. On the other hand, if the condition in the third step is not met, the process proceeds to the deterioration sign judgment process, which will be explained later.

[0108] Here, the matching condition for the individual flame observation values ​​ΣD1 and ΣD2 is arbitrary, but for example, it is determined that the matching condition is satisfied when the interval ratio (ΣD1 / ΣD2) of the individual flame observation values ​​ΣD1 and ΣD2 is within a predetermined range, for example, when the difference between the individual flame observation values ​​ΣD1 and ΣD2 is within a predetermined value. In other words, it is determined that the matching condition is satisfied when the interval ratio (ΣD1 / ΣD2) is within a predetermined ratio centered on 1.

[0109] In addition, the process of "accumulating the first flame candidate determination result" in the aforementioned fifth step is optional, but for example, a first flame candidate counter may be prepared, and if a first flame candidate is determined to be a first flame candidate, the first flame candidate counter may be incremented by one (+1).

[0110] In this type of first flame candidate judgment process, steps 1 to 5 are repeated until the accumulation number of the first flame candidate, for example the first flame candidate counter, reaches a predetermined threshold number and the accumulation condition for the first flame candidate is satisfied, and when the accumulation condition for the first flame candidate is satisfied, i.e., when the count value of the first flame candidate counter reaches a predetermined threshold number, the process proceeds to the second flame candidate judgment process described next.

[0111] (e2. Determining the second flame candidate) Next, the determination of the second flame candidate will be described. The process of determining the second flame candidate is performed based on the frequency analysis result of performing a fast Fourier transform (FFT) on the additive flame observation value D0 for, for example, 2 seconds stored in the memory, and the determination process is performed as follows.

[0112] In the process of determining the second flame candidate, as a first step, a fast Fourier transform is performed on the 256 flame observation values ​​D0 stored in the memory, and a frequency analysis result shown as an example in FIG. 7 is obtained.

[0113] In the second step, if the acquired frequency analysis result satisfies the second flame candidate determination condition, it is determined to be a second flame candidate, and the determination result is stored.

[0114] In the third step, when the accumulation count of the second flame candidate reaches a predetermined threshold count and the accumulation condition is satisfied, it is determined that there is a fire, and a fire detection signal is sent to the disaster prevention receiving panel.

[0115] Here, as shown in Figure 7, when observing the radiation energy emitted from a combustion flame on the frequency axis, a frequency characteristic showing a high output level is obtained in the frequency band FL on the generally low frequency side, so the main frequency components of the received light signal E0 are present in the frequency band FL on the low frequency side, and the frequency components in the frequency band FH on the high frequency side show a low level. Such frequency characteristics are characteristic of signals when observing a combustion flame.

[0116] For this reason, the "second flame candidate determination condition" in the second procedure calculates the integral value ΣFL of the low frequency band FL and the integral value ΣFH of the high frequency band FH, and if the ratio of the two integral values ​​(ΣFL / ΣFH) is equal to or greater than a predetermined threshold, it is determined that the second flame candidate determination condition is met and the second flame candidate determination result is stored. On the other hand, if the ratio (ΣFL / ΣFH) is less than the predetermined threshold and the second flame candidate determination condition is not met, the process proceeds to a deterioration sign determination process, which will be explained later.

[0117] In addition, the process of determining whether a second flame is a candidate may be performed by setting a plurality of different second flame candidate determination conditions instead of the single second flame candidate determination condition described above, and when all of the second flame candidate determination conditions are satisfied, the second flame is determined to be a candidate, and the determination result may be accumulated.

[0118] In addition, the process of "accumulating the determination result of the second flame candidate" in the third step is optional, but similar to the accumulation of the first flame candidate, for example, a second flame candidate counter is prepared, and when a second flame candidate is determined to be a second flame candidate, the second flame candidate counter is incremented by one (+1), and when the count value of the second flame candidate counter reaches a predetermined threshold number, the accumulation condition is considered to be satisfied.

[0119] Therefore, if the accumulation condition for the first flame candidate is, for example, a predetermined threshold number of times for the count value of the first flame candidate counter is set to m times, and the accumulation condition for the second flame candidate is, for example, a predetermined threshold number of times for the count value of the second flame candidate counter is set to n times, then the determination process for the first flame candidate is required (m x n) times, and the determination process for the second flame candidate is required n times, before it is determined that there is a fire.

[0120] [f. Deterioration sign determination unit] Next, a description will be given of the deterioration sign determination unit 4820 provided in the detector control unit 48. The deterioration sign determination unit 4820 determines a deterioration sign based on a first non-flame candidate (section ratio determination NG) determination when the section ratio (ΣD1 / ΣD2) does not satisfy the matching condition in the determination process of the first flame candidate in the fire determination process by the fire determination unit 4810, and a second non-flame candidate (FFT determination NG) determination when the candidate is determined to be the first flame candidate but the frequency analysis result does not satisfy the second flame candidate determination condition in the determination process of the second flame candidate, and transmits a deterioration sign signal to the disaster prevention receiving panel when determining a deterioration sign.

[0121] (f1. Judgment of the first non-flame candidate) First, a description will be given of the determination of a first non-flame candidate (interval ratio determination NG) by the deterioration sign determination unit 4820. When the individual flame observation values ​​ΣD1, ΣD2 acquired by the fire determination unit 4810 do not satisfy a predetermined matching condition, the deterioration sign determination unit 4820 performs a process of determining the first non-flame candidate (interval ratio determination NG) and accumulating the determination result of the first non-flame candidate, and when the accumulated number of times of the first non-flame candidate reaches a predetermined threshold number within a predetermined period, for example, 8 hours, it determines the first non-flame candidate as a deterioration sign candidate and accumulates the determination result of the deterioration sign candidate.

[0122] The accumulation process of the first non-flame candidates by the deterioration sign determination unit 4820 is arbitrary, but for example, similar to the accumulation process described above, a first non-flame candidate counter is provided, and if the individual flame observation values ​​ΣD1 and ΣD2 do not satisfy a specified matching condition, the first non-flame candidate counter is incremented by one (+1).

[0123] The deterioration sign determination unit 4820 also accumulates deterioration sign candidates in a similar manner, and for example, like the accumulation process described above, has a deterioration sign candidate counter, and when the count value of the first non-flame candidate counter reaches a predetermined threshold, it increments the deterioration sign candidate counter by one (+1).

[0124] (f2. Judgment of the second non-flame candidate) Next, the determination of the second non-flame candidate (FFT determination NG) by the deterioration sign determination unit 4820 will be described. The deterioration sign determination unit 4820 performs a process of determining and storing the second non-flame candidate when the first flame candidate is determined to be the first flame candidate by the fire determination unit 4810 through the determination process of the first flame candidate, but the frequency analysis result of the fast Fourier transform (FFT) of the flame observation value D0 in the determination process of the second flame candidate does not satisfy the second flame candidate determination condition, and determines it as a deterioration sign candidate when the accumulation number of the second non-flame candidate reaches a predetermined threshold number within a predetermined period, for example, 8 hours, and accumulates the determination result of the deterioration sign candidate. That is, when the accumulation number of the first non-flame candidate described above reaches a predetermined threshold number and when the accumulation number of the second non-flame candidate reaches a predetermined threshold number, the determination result of the deterioration sign candidate is accumulated.

[0125] The accumulation process of the second non-flame candidates by the deterioration sign determination unit 4820 is arbitrary, but for example, similar to the accumulation process described above, a second non-flame candidate counter is provided, and if the frequency analysis result does not satisfy the second flame candidate determination condition, the second non-flame candidate counter is incremented by one (+1).

[0126] The deterioration sign determination unit 4820 also accumulates deterioration sign candidates in a similar manner, and for example, like the accumulation process described above, has a deterioration sign candidate counter, and when the count value of the second non-flame candidate counter reaches a predetermined threshold, it increments the deterioration sign candidate counter by one (+1).

[0127] (f3. Judging signs of deterioration) Next, a description will be given of the determination of a deterioration sign by the deterioration sign determination unit 4820. As described above, the deterioration sign determination unit 4820 determines whether the accumulated number of times of the first non-flame candidate (section ratio determination NG) reaches a predetermined threshold number of times (condition 1) and whether the accumulated number of times of the second non-flame candidate (FFT determination NG) reaches a predetermined threshold number of times (condition 2) for each predetermined period, accumulates the determination result of the deterioration sign candidate when condition 1 or condition 2 is satisfied, and determines that a deterioration sign has occurred when the accumulated number of times of the deterioration sign candidate reaches a predetermined threshold number of times, for example, when the count value of a deterioration sign candidate counter reaches a predetermined threshold.

[0128] (f4, Prevention of erroneous judgment of deterioration signs due to external vibration) Next, the prevention of erroneous judgment of deterioration signs caused by external vibrations as a cause of erroneous judgment will be described. Since the pyroelectric body provided as a light receiving element in the light receiving element parts 62R and 62L also functions as a piezoelectric element, when the fire detector 12 installed on the wall of a tunnel or the like is subjected to strong vibrations due to the passage of a large vehicle or an earthquake, the light receiving signals E1 and E2 output from the two main amplifiers of the 4.5 μm light receiving processing part and the light receiving signal E0 output from the adder 94 may contain frequency components including a distribution of flame-specific frequency bands of 2 to 8 Hz caused by external vibrations.

[0129] Therefore, there is a risk that the deterioration sign is judged based on the digital light reception value stored in the memory due to the external vibration, and the judgment result is accumulated. Therefore, when judging the second non-flame candidate, if the accumulated number of times of the second non-flame candidate reaches a predetermined threshold number, the deterioration sign judgment unit 4820 judges whether or not the judgment of the second non-flame candidate has been affected by the external vibration, and if it is judged to have been affected by the external vibration, the deterioration sign judgment unit 4820 does not perform the process of not accumulating the judgment of the deterioration sign candidate even if the accumulated number of times of the second non-flame candidate reaches a predetermined threshold number.

[0130] The process of preventing the deterioration sign candidate determination by the deterioration sign determination unit 4820 from being accumulated is optional, but for example, the following process is performed.

[0131] First, the fire detector 12 monitors two different detection areas individually, and is provided with two sets of fire detection units 60R and 60L on the left and right. That is, the determination process in the fire determination unit 4810 and the deterioration sign determination unit 4820 is performed individually based on the observation values ​​observed in the detection area corresponding to the right eye fire detection unit 60R and the detection area corresponding to the left eye fire detection unit 60L.

[0132] Therefore, the deterioration sign determination unit 4820 accumulates the second non-flame candidate determined when the frequency analysis result of fast Fourier transform of the flame observation value D0 observed in the detection area corresponding to the right eye fire detection unit 60R and stored in memory does not satisfy the second flame candidate determination condition as a "right eye only non-flame candidate."

[0133] Similarly, the deterioration sign determination unit 4820 accumulates the second non-flame candidate determined to be a "left eye only non-flame candidate" when the frequency analysis result of fast Fourier transform of the flame observation value D0 observed in the detection area corresponding to the left eye fire detection unit 60L and stored in memory does not satisfy the second flame candidate determination condition.

[0134] In addition, if the deterioration sign determination unit 4820 determines both a "right eye only non-flame candidate" based on the right eye fire detection unit 60R and a "left eye only non-flame candidate" based on the left eye fire detection unit 60L within a specified period, it accumulates them as "simultaneous non-flame candidates."

[0135] Then, when the accumulated number of times of any single non-flame candidate reaches a predetermined threshold number, the deterioration sign determination unit 4820 calculates the ratio (N1 / N2) of the accumulated number N1 of the single non-flame candidate to the accumulated number N2 of the simultaneous non-flame candidate, and if the ratio (N1 / N2) satisfies a predetermined ratio determination condition, it determines that the candidate is a deterioration sign candidate and accumulates it, but if the ratio (N1 / N2) does not satisfy the ratio determination condition, it does not determine that the candidate is a deterioration sign candidate as being affected by external vibrations and does not accumulate it.

[0136] This type of processing is performed because the fire detector 12 is equipped with different fire detection units 60R, 60L corresponding to the detection area, and if deterioration or signs of deterioration appear in one of the fire detection units, it does not affect the other fire detection unit and is not accumulated as a "simultaneous non-flame candidate." However, if the fire detector 12 is affected by external vibrations, there is a high possibility that it will affect both fire detection units 60R, 60L and will be accumulated as a "simultaneous non-flame candidate." A single non-flame candidate is treated as a sign of deterioration, and a simultaneous non-flame candidate is treated as an influence of external vibrations.

[0137] Furthermore, the accumulated number N2 of simultaneous non-flame candidates caused by external vibrations is considerably smaller than the accumulated number N1 of single non-flame candidates, and the accumulated number (N1-N2) obtained by subtracting the accumulated number N2 of simultaneous non-flame candidates from the accumulated number N1 of single non-flame candidates is the accumulated number of true non-disaster candidates for determining signs of deterioration of the fire detector 12 excluding the effects of external vibrations.

[0138] For example, if the accumulated number N1 of single non-flame candidates is 100, then the accumulated number N2 of simultaneous non-flame candidates is approximately 2. As a ratio judgment condition, for example, a ratio threshold value TH=50 is set, and if the ratio (N1 / N2) falls below the ratio threshold value of 50, it is determined that there is an influence of external vibration, and an inhibitory process is performed in which the judgment of deterioration sign candidates is not accumulated.

[0139] In addition, since the frequency of occurrence of the effects of external vibrations is expected to be extremely low, if external vibrations are considered to be the main cause of erroneous judgment, the fire detector 12 does not need to be provided with a processing function for preventing erroneous judgment of signs of deterioration.

[0140] [g. Test control section] Next, the test control section 4830 provided in the detector control section 48 will be described. When the test control section 4830 receives a test instruction by a test signal from the disaster prevention receiving panel 10 periodically, for example, once every 24 hours (once a day), the test control section 4830 performs a sensitivity test for monitoring the sensitivity of the light receiving element section and a dirt test for monitoring dirt on the light-transmitting window. The same applies when the disaster prevention receiving panel 10 is manually operated to transmit a test signal.

[0141] Taking the sensitivity test of the light receiving element 62R of the right eye fire detection unit 60R as an example of a sensitivity test, when the test control unit 4830 receives a test signal periodically transmitted from the disaster prevention receiving panel 10, it detects the light receiving sensitivity (light receiving value) by making test light equivalent to light from a simulated flame enter the light receiving element 62R from the internal test light source 82R, and when the detected value drops to a predetermined sensitivity threshold, it transmits a response signal of sensor failure (sensitivity abnormality) to the disaster prevention receiving panel 10 to output a sensor failure alarm (sensitivity abnormality alarm). The same applies when the disaster prevention receiving panel 10 is manually operated to transmit a test signal.

[0142] As an example of a dirt test, taking the dirt test of the light-transmitting window 80R of the right eye fire detection unit 60R as an example, when a test signal periodically transmitted from the disaster prevention receiving panel 10 is received, the test control unit 4830 causes test light from an external test light source 84R provided outside the fire detector 10 to enter the light-transmitting window 80R, receives the light with the light receiving element unit 62R, and obtains the light attenuation rate. If the light attenuation rate is equal to or greater than the first predetermined dirt threshold and less than the second predetermined dirt threshold, the received light value is corrected to maintain the fire detection function, and if the light attenuation rate is equal to or greater than the second predetermined dirt threshold, a response signal indicating an abnormality in dirt is transmitted to the disaster prevention receiving panel to output a dirt alarm. The same applies when the disaster prevention receiving panel 10 is manually operated to transmit a test signal.

[0143] [h. Fire detector processing operation] Next, the processing operation of the fire detector will be described. In this description, reference will be made to Fig. 8 which is a flowchart showing the processing operation of the fire detector. The processing operation of the fire detector to be described is the processing operation by the fire determination unit 4810 and the deterioration sign determination unit 4820 provided in the detector control unit 48 of the fire detector 12. The processing operation of the fire detector will be described based on the observation value acquired by the right eye fire detection unit 60R, but the same applies to the case of the observation value acquired by the left eye fire detection unit 60L.

[0144] (h1. Fire detection operation) First, a fire detection operation when the fire detector 12 detects infrared energy from a burning flame caused by a fire in the detection area corresponding to the right eye fire detection section 60 of the fire detector 12 will be described.

[0145] As shown in Figure 8, the fire judgment unit 4810 of the detector control unit 48 acquires a predetermined number of digital light reception values ​​output from the right eye fire detection unit 60R over a predetermined period of time and stores them in memory, and obtains an aggregate flame observation value ΣD0, an individual flame observation value ΣD1, an individual flame observation value ΣD2, a non-flame observation value ΣD3 and a non-flame observation value ΣD4 as observation values ​​for three wavelengths by integrating the digital light reception values ​​stored in the memory (steps S1 to S2).

[0146] Next, the fire judgment unit 4810 judges whether the acquired observation values ​​of the three wavelengths satisfy the judgment conditions, i.e., whether the judgment conditions that the additive flame observation value ΣD0 is greater than or equal to a predetermined threshold, that the ratio (ΣD0 / ΣD3) is greater than or equal to a predetermined threshold, and that the ratio (ΣD0 / ΣD4) is greater than or equal to a predetermined threshold in the first to third steps described above in "e1. Judgment of the first flame candidate" are satisfied (step S3).

[0147] Next, if the observation values ​​of the three wavelengths satisfy the judgment conditions, the fire judgment unit 4810 judges whether the interval ratio (ΣD1 / ΣD2) satisfies the matching condition, that is, whether the individual flame observation values ​​ΣD1, ΣD2 in the fourth step described above in "e1. Judging the first flame candidate" satisfy the predetermined matching condition, and if the interval ratio satisfies the matching condition, judges it to be the first flame candidate and accumulates the judgment result of the first flame candidate (steps S4 to S5).

[0148] Next, the fire judgment unit 4810 judges whether the accumulated number of times that it has been judged as a first flame candidate satisfies a predetermined accumulation condition, and if it judges that the accumulation condition is satisfied, it performs a fast Fourier transform on the added flame observation value D0 stored in the memory to obtain a frequency analysis result, and judges whether the obtained frequency analysis result satisfies a second flame candidate judgment condition, and if the frequency analysis result satisfies the judgment condition, it judges it as a second flame candidate and accumulates the judgment result of the second flame candidate (steps S6 to S8).

[0149] Next, the fire determination unit 4810 determines whether the accumulated number of times the second flame candidate has been determined to be present satisfies a predetermined accumulation condition, and if it determines that the accumulation condition is satisfied, it detects a fire and transmits a fire detection signal to the disaster prevention receiving panel 10, causing a predetermined fire alarm operation and linked operation of the tunnel disaster prevention equipment to be performed (steps S9 to S10).

[0150] In addition, if the predetermined number of digital received light values ​​are not obtained in step S1, if the observation values ​​of the three wavelengths do not satisfy the judgment conditions in step S3, if the accumulation count determined to be the first flame candidate in step S6 does not satisfy the predetermined accumulation conditions, or if the accumulation count determined to be the second flame candidate in step S9 does not satisfy the predetermined accumulation conditions, the process returns to before step S1.

[0151] If the section ratio does not satisfy the coincidence condition in step S4, and if the frequency analysis result does not satisfy the second flame candidate determination condition in step S7, the process proceeds to the degradation sign determination process described next.

[0152] (h2.Deterioration sign judgment operation) Next, the deterioration sign determining operation accompanying the above-mentioned fire detection operation will be described.

[0153] As described above, when the fire detection operation (steps S1 to S10) is being performed by the fire determination unit 4810, if the section ratio (ΣD1 / ΣD2) does not satisfy the matching condition in step S4, the deterioration sign determination unit 4820 determines the first non-fire candidate and accumulates the determination result of the first non-fire candidate. The accumulation of the first non-fire candidate is reset at predetermined time intervals (steps S4, S11 to S12).

[0154] Next, the deterioration sign determination unit 4820 determines whether the accumulated number of times determined as the first non-flame candidate satisfies a predetermined accumulation condition, and if it determines that the accumulation condition is satisfied, it determines it as a deterioration sign candidate and accumulates the deterioration sign candidate determination result (steps S13 to S14). On the other hand, if the accumulated number of times the first non-flame candidate does not satisfy the accumulation condition in step S13, the process returns to before step S1.

[0155] Furthermore, when the fire detection operation (steps S1 to S10) is being performed by the fire determination unit 4810, if the frequency analysis result does not satisfy the second flame candidate determination condition in step S7, the deterioration sign determination unit 4820 determines it as a second non-flame candidate and accumulates the determination result of the second non-flame candidate (single non-flame candidate for the right eye). The accumulation of the second non-flame candidates is reset at predetermined time intervals (steps S7, S19 to S20). On the other hand, if the accumulation count of the second non-flame candidate does not satisfy the accumulation condition in step S21, the process returns to before step S1. The same process is performed for the single non-flame candidate for the left eye.

[0156] Next, the deterioration sign determination unit 4820 determines whether the accumulated number of times determined to be the second non-flame candidate satisfies a predetermined accumulation condition, and if it determines that the accumulation condition is satisfied, it determines whether the ratio (N1 / N2) of the accumulated number N1 of the right eye single non-flame candidate to the accumulated number N2 of simultaneous non-flame candidates based on both the right eye single non-flame candidate (second non-flame candidate caused by the right eye fire detection unit 60R) and the left eye single non-flame candidate (second non-flame candidate caused by the left eye fire detection unit 60L) as described above in "f4. Preventing erroneous determination of deterioration signs due to external vibration" satisfies a predetermined ratio determination condition, and if it determines that the determination is not due to external vibration (the ratio satisfies the predetermined ratio determination condition), it determines that the deterioration sign candidate is a deterioration sign candidate and accumulates the determination result of the deterioration sign candidate (steps S21 to S22, S14). On the other hand, if it is determined in step S22 that the erroneous determination was due to external vibration, the process returns to before step S1 without accumulating deterioration sign candidates.

[0157] The deterioration sign determination unit 4820 then determines whether the accumulation count determined as a deterioration sign candidate satisfies a predetermined accumulation condition, and if it determines that the accumulation condition is satisfied, it determines that it is a deterioration sign, and if it detects a test instruction transmitted from the disaster prevention receiving panel 10 at a predetermined timing, it transmits a deterioration sign signal indicating a deterioration sign to the disaster prevention receiving panel 10 at the response timing, and causes a predetermined alarm operation to be performed (steps S15 to S18). On the other hand, if the accumulation condition is not satisfied in step S15 or if a test instruction is not detected in step S17, the process returns to before step S1. The deterioration sign determination is performed for each of the left eye and the right eye, and the deterioration sign signal is also output for each of the left eye and the right eye.

[0158] Incidentally, the deterioration sign signal may be transmitted when it is determined in step S15 that the accumulation condition is satisfied, regardless of the test command from the disaster prevention receiving panel 10.

[0159] In addition, since the frequency with which the erroneous judgment in step S22 is influenced by external vibrations is extremely low, it is possible to judge it as a deterioration sign candidate and accumulate the judgment result of the deterioration sign candidate without performing the processing in step S22 if the accumulated number of times the second non-flame candidate satisfies the accumulation condition in step S21.

[0160] [i. Operation of the disaster prevention receiving panel] Next, the operation of the disaster prevention receiving panel will be described.

[0161] When the disaster prevention receiving panel 10 receives a deterioration sign signal from the fire detector 12, it performs a predetermined alarm operation, for example, displaying the deterioration sign. As the deterioration sign display, the disaster prevention receiving panel 10 displays, for example, on the screen of the display of the display unit 40, a message indicating that a deterioration sign has been detected together with information (detector address, etc.) capable of identifying the fire detector for which a deterioration sign has been detected.

[0162] In addition, when the response to a fire detector 12 that has been determined to show signs of deterioration has been completed, the fact that the response has been completed may be input by operating the disaster prevention receiving panel 10, and when the fact that the response has been completed is input, the fire detector in question may be automatically removed from the display of signs of deterioration.

[0163] Furthermore, when the disaster prevention receiving panel 10 receives a deterioration sign signal from the fire detector 12, it generates and stores history information on the deterioration sign, and is capable of displaying the history of the deterioration sign. The disaster prevention receiving panel 10 is capable of displaying, for example, a list of history including not only the deterioration signs but also other events such as fires and failures as the history display. Furthermore, the history list does not have to be capable of displaying all states, but may be capable of displaying any state, such as a display of history of only the deterioration signs or a display of history of failures and the deterioration signs, and may be capable of switching which state is displayed by an operation.

[0164] The deterioration sign display and history display may be displayed in a list for a specific fire detector 10 in that state. The list display may be arranged, for example, in order of address or in order of judgment, and the list order may be switchable.

[0165] The disaster prevention receiving panel 10 may also display the current status information of each fire detector. For example, the status information may be displayed by arranging the fire detectors as icons, and the icon display may be changed according to the status of the fire detector, for example, a white icon in normal operation, a red icon in fire detection, a yellow icon in failure (sensitivity abnormality, dirt abnormality, etc.), and an orange icon in indication of deterioration. In addition, when information to be displayed for one fire detector overlaps, the priority order may be set to, for example, (when fire is detected) → (when failure occurs) → (when indication of deterioration) → (when normal operation) in descending order of priority, or the icon may be divided to display all the colors of the information to be displayed.

[0166] Furthermore, when the disaster prevention receiving panel 10 receives a fire detection signal from the fire detector 12, it displays, for example, the occurrence of a fire as a predetermined fire alarm operation. When displaying the occurrence of a fire, if the disaster prevention receiving panel 10 has separately received a deterioration predictive signal from the fire detector 12 that received the fire detection signal, the disaster prevention receiving panel 10 may display an indication that the fire detector 12 has determined a deterioration predictive signal.

[0167] [j. Modifications of the present invention] Modifications of the fire detector and tunnel disaster prevention system according to the present invention will now be described. In addition to the above-described embodiment, the fire detector and tunnel disaster prevention system according to the present invention also include the following modifications.

[0168] (Fire detector) The above embodiment takes a three-wavelength fire detector as an example, but other systems may be used. For example, it may be a two-wavelength fire detector that detects a fire and determines signs of deterioration based on a light receiving signal in a wavelength band having a central wavelength of 4.5 μm and a light receiving signal in a wavelength band having a central wavelength of 5.0 μm.

[0169] (Determination of section ratio) In the above embodiment, one condition for determining that a flame is a first flame candidate is that the individual flame observation values ​​ΣD1, ΣD2 obtained by integrating the digital light receiving values ​​obtained in response to the reception of radiation energy from the combustion flame by the two sets of light receiving element units 62R, 62L satisfy a predetermined matching condition. However, this is not limited to this, and a condition for determining that a flame is a first flame candidate may be that the interval of the digital light receiving values ​​is divided into multiple intervals, for example, an early interval, a middle interval, and a late interval, and all of the interval ratios R1 = (ΣD11 / ΣD12), R2 = (ΣD21 / ΣD22), and R3 = (ΣD31 / ΣD32) of the individual flame observation values ​​(ΣD11, ΣD12), (ΣD21, ΣD22), and (ΣD31, ΣD32) obtained by integrating each interval satisfy a predetermined matching condition. If all of the interval ratios R1 to R3 do not satisfy the condition, the flame is determined to be a first non-flame candidate, thereby further improving the accuracy of the interval ratio determination.

[0170] The matching condition for the section ratios R1 to R3 is, for example, Predetermined value A≦R1≦predetermined value B Predetermined value A≦R2≦predetermined value B Predetermined value A≦R3≦predetermined value B Conditions such as Predetermined value A・R1≦R2≦Predetermined value B・R1 Predetermined value A・R1≦R3≦Predetermined value B・R1 The condition may be as follows: The predetermined value A is a predetermined value equal to or less than 1, and the predetermined value B is a predetermined value equal to or more than 1.

[0171] (others) Furthermore, the present invention is not limited to the above-described embodiment, but includes appropriate modifications that do not impair the objects and advantages of the present invention, and is not limited to the numerical values ​​shown in the above-described embodiment. [Explanation of symbols]

[0172] 1a: Up line tunnel 1b: Down line tunnel 10: Disaster prevention receiving panel 12: Fire detector 1210: Cabinet 14, 14a, 14b: Transmission line 16: Fire pump equipment 18: Cooling pump equipment 20:IG slave station equipment 22: Ventilation equipment 24: Alarm display board equipment 26: Radio rebroadcasting equipment 28: TV surveillance equipment 30: Lighting equipment 32: Remote monitoring and control equipment 34: Panel control unit 36, 36a, 36b: Transmission section 38: Alarm section 40: Display section 42:Operation unit 44: Modem 46: IO Department 48: Detector control unit 4810:Fire judgment department 4820: Deterioration sign determination unit 4830: Test control unit 50: Transmission section 52: Power supply section 54: Test power supply section 56: Test light emission driver 60R, 60L: Fire detection unit 62R, 62L, 64R, 64L, 66R, 66L: Light receiving element section 68R, 68L: 4.5μm light receiving processing part 70R, 70L: 5.0μm light receiving processing section 72R, 72L: 2.3μm light receiving processing section 74R, 74L, 76R, 76L, 78R, 78L: Optical wavelength filters 80R,80L: Translucent window 81R, 81L: Translucent window for test light source 82R, 82L: Internal test light source 84R, 84L: External test light source 86, 96, 104: Pre-filter 88, 98, 106: Preamplifier 90, 100, 108: Main amplifier 92, 102, 110: Final stage amplifier 94: Adder 112, 114, 116, 118, 120: A / D conversion ports

Claims

1. A fire detector that detects a fire based on a flame observation value obtained by observing radiation energy emitted from a fire flame, a fire determination unit that determines that a fire has occurred when a plurality of flame determination conditions based on the flame observation value are satisfied; a deterioration sign determination unit that determines a non-flame candidate when the fire determination unit satisfies some of the plurality of flame determination conditions but does not satisfy other flame determination conditions, and determines a deterioration sign of the fire detector based on the non-flame candidate determination result; A fire detector comprising:

2. 2. The fire detector according to claim 1, The fire determination unit determines that one of the plurality of flame determination conditions is satisfied when a frequency analysis result of the flame observation value or a value based on the flame observation value satisfies a predetermined determination condition, The deterioration sign determination unit determines that the fire detector is a non-flame candidate based on frequency analysis when the frequency analysis result does not satisfy the predetermined determination condition.

3. 3. The fire detector according to claim 2, The deterioration sign determination unit determines the deterioration sign of the fire detector when the number of times that non-flame candidates are determined based on the frequency analysis satisfies a predetermined accumulation condition within a predetermined period of time.

4. 3. The fire detector according to claim 2, As a predetermined judgment condition for the frequency analysis result, it is judged whether the frequency analysis result obtained by performing a fast Fourier transform on the flame observation value or a value based on the flame observation value includes a frequency distribution specific to a flame; A fire detector characterized in that, when the frequency analysis result obtained by the fast Fourier transform includes a frequency distribution specific to the flame, the frequency analysis result of the flame observation value or a value based on the flame observation value satisfies the specified judgment condition.

5. 3. The fire detector according to claim 2, A fire detector characterized in that, when the deterioration sign determination unit determines a non-flame candidate based on the frequency analysis, it determines whether the determination is an erroneous determination due to a specified erroneous determination factor, and if it determines that the determination is an erroneous determination due to the specified erroneous determination factor, it does not add to the number of times that a non-flame candidate has been determined based on the frequency analysis.

6. 6. The fire detector according to claim 5, The fire detector monitors fires in a plurality of detection areas by observing different detection areas individually; The deterioration sign determination unit is A non-flame candidate determined based on frequency analysis in a specified detection area is stored as a single non-flame candidate, and a non-flame candidate determined based on frequency analysis in another detection area within a specified period is stored as a simultaneous non-flame candidate; A fire detector characterized in that it determines whether an erroneous judgment is due to the specified erroneous judgment factor based on a ratio of the accumulated number of times of the single non-flame candidate to the accumulated number of times of the simultaneous non-flame candidate.

7. 2. The fire detector according to claim 1, A fire detector characterized in that it is capable of outputting a fire detection signal to the outside when the fire judgment unit judges that there is a fire, and outputting a deterioration sign signal to the outside after the deterioration sign judgment unit judges that there is a sign of deterioration of the fire detector.

8. 2. The fire detector according to claim 1, A fire detector characterized in that, when the deterioration sign determination unit determines that there is a deterioration sign of the fire detector, the fire determination unit continues the fire determination process without stopping it.

9. 13. A tunnel disaster prevention system comprising: a plurality of fire detectors according to claim 1, which are installed at predetermined intervals in the longitudinal direction of a tunnel and which are connected to a disaster prevention receiving panel.

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