JP2022068628A - Fire alarm device - Google Patents

Abstract

To provide a fire alarm device capable of restricting a person in a fire site from failing in escape.SOLUTION: A fire alarm device 1 includes: a CO sensor 2 for detecting a carbon monoxide concentration contained in an environment atmosphere; and a smoke sensor 3 for detecting a smoke concentration contained in the environment atmosphere. The fire alarm device 1 issues alarm when the smoke concentration to be detected by the smoke sensor 3 exceeds a predetermined smoke alarm threshold. The fire alarm device 1 calculates a carbon monoxide hemoglobin concentration in blood from the carbon monoxide concentration to be detected by the CO sensor 2, and reduces the smoke alarm threshold when the carbon monoxide hemoglobin concentration to be calculated exceeds a predetermined carbon monoxide hemoglobin concentration threshold.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fire alarm.

Fire alarms for detecting the occurrence of a fire have a predetermined smoke concentration to be detected, as stipulated in the "Ministry Ordinance that Establishes Technical Standards for Residential Disaster Prevention Alarms and Residential Disaster Prevention Notification Equipment". It must be configured to issue an alarm when the smoke alarm threshold is exceeded. The smoke warning thresholds to be adopted are set by ministerial ordinances, for example, 5% / m (type 1) and 10% / m (type 2). In order to detect the occurrence of a fire as soon as possible and ensure personal safety, it is desirable to adopt the smoke warning threshold of 5% / m (type), which is as low as possible. However, in the case of fire alarms used for residential purposes, if 5% / m (a type) is adopted as the smoke alarm threshold, it will react to even a small amount of smoke such as cigarette smoke and smoke generated during cooking. Since there is a high possibility that an erroneous report will be issued, 10% / m (two types) is generally adopted as the smoke alarm threshold.

In order to detect the occurrence of a fire as soon as possible, for example, a fire alarm as disclosed in Patent Document 1 is used. The fire alarm of Patent Document 1 includes a CO sensor that detects carbon monoxide in addition to a smoke sensor that detects smoke. The fire alarm of Patent Document 1 determines that a fire has occurred when the detected amount of smoke and carbon monoxide obtained from the smoke sensor and the CO sensor and the rate of change in the detected amount exceed a predetermined threshold value. Issue an alarm. When a fire breaks out, carbon monoxide is often generated before the smoke is generated, and it is possible to detect the fire occurrence at an early stage by detecting not only the smoke but also the carbon monoxide.

Japanese Unexamined Patent Publication No. 2006-277138

In the fire alarm of Patent Document 1, an alarm is issued only when the detected smoke and carbon monoxide parameters exceed a predetermined threshold value and it can be determined that a fire has occurred. However, people at the fire site may already have difficulty evacuating even if an alarm is issued in a situation where it can be determined that a fire has occurred. For example, if a person at a fire site is in a situation where a low carbon monoxide concentration that cannot be determined that a fire has occurred is detected for a long time, one in the blood without warning of a fire. The concentration of carbon monoxide hemoglobin may increase, resulting in a decrease in human function. In that case, even if the alarm is issued only when the person at the fire site can determine that a fire has occurred after that, the human body function has already deteriorated and the person is delayed in escaping from the fire site. there is a possibility. It is conceivable to lower the smoke warning threshold and the carbon monoxide warning threshold in order to detect the occurrence of a fire at an early stage, but blindly lowering the threshold leads to the occurrence of false alarms.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a fire alarm capable of suppressing an escape delay of a person at a fire site.

The fire alarm device of the present invention includes a CO sensor that detects the concentration of carbon monoxide contained in the environmental atmosphere and a smoke sensor that detects the concentration of smoke contained in the environmental atmosphere, and the smoke detected by the smoke sensor. A fire alarm configured to issue an alarm when the concentration exceeds a predetermined smoke alarm threshold, the fire alarm is carbon monoxide in blood from the carbon monoxide concentration detected by the CO sensor. The hemoglobin concentration is calculated, and when the calculated carbon monoxide hemoglobin concentration exceeds a predetermined carbon monoxide hemoglobin concentration threshold, the smoke warning threshold is lowered.

In addition, the fire alarm corrects the calculated carbon monoxide hemoglobin concentration according to the distance between the assumed fire occurrence location and the installation location where the fire alarm is installed. It is preferable that the smoke alarm threshold is lowered when the carbon monoxide hemoglobin concentration exceeds the predetermined carbon monoxide hemoglobin concentration threshold.

Further, in the fire alarm, the carbon monoxide concentration detected by the CO sensor exceeds a predetermined carbon monoxide threshold lower than a predetermined carbon monoxide alarm threshold as a reference for issuing an alarm. , It is preferable that the calculation of the carbon monoxide hemoglobin concentration is started.

Further, when the duration of the carbon monoxide concentration detected by the CO sensor to be equal to or less than a predetermined value exceeds a predetermined time, the fire alarm is calculated by the time when the predetermined time has elapsed. It is preferable that the hemoglobin concentration is set to zero and the lowered smoke alarm threshold is returned to the original value.

Further, it is preferable that the fire alarm is configured to issue an alarm when the carbon monoxide concentration detected by the CO sensor exceeds a predetermined carbon monoxide alarm threshold value.

According to the present invention, it is possible to provide a fire alarm that can suppress the escape delay of a person at a fire site.

It is a block diagram of the fire alarm which concerns on one Embodiment of this invention. It is a figure which shows schematically the room where the fire alarm system which concerns on one Embodiment of this invention is installed. It is a flowchart which shows schematicly the main step carried out in the fire alarm system which concerns on one Embodiment of this invention. It is a flowchart which shows the substep which is carried out in the fire alarm system which concerns on one Embodiment of this invention. It is a flowchart which shows the substep which is carried out in the fire alarm system which concerns on one Embodiment of this invention. It is a flowchart which shows the substep which is carried out in the fire alarm system which concerns on one Embodiment of this invention. It is a flowchart which shows the substep which is carried out in the fire alarm system which concerns on one Embodiment of this invention. It is a flowchart which shows the substep which is carried out in the fire alarm system which concerns on one Embodiment of this invention. The carbon monoxide concentration, the carbon monoxide hemoglobin concentration, and the carbon monoxide hemoglobin concentration obtained by the fire alarm according to the embodiment of the present invention installed on the ceiling of the room when the futon on the floor surface of the room is burned by a fire source. It is a graph which shows the time change of a smoke concentration. The carbon monoxide concentration and carbon monoxide obtained by the fire alarm according to the embodiment of the present invention installed on the ceiling of the room and near the fire source when the futon on the floor of the room is burned by the fire source. It is a graph which shows the time change of the carbon hemoglobin concentration.

Hereinafter, the fire alarm according to the embodiment of the present invention will be described with reference to the accompanying drawings. However, the embodiment shown below is only an example, and the fire alarm of the present invention is not limited to the following example.

As shown in FIG. 1, the fire alarm 1 of the present embodiment detects a CO sensor 2 that detects the concentration of carbon monoxide (CO) contained in the environmental atmosphere and a smoke concentration contained in the environmental atmosphere. It is equipped with a smoke sensor 3. The fire alarm 1 is configured to issue an alarm when the smoke concentration detected by the smoke sensor 3 exceeds a predetermined smoke alarm threshold value. As shown in FIG. 2, for example, the fire alarm 1 is installed and used in a room R of a house for residential use. However, the fire alarm 1 is not limited to the residential use, and can be used for other purposes such as an automatic fire alarm system used in an office or the like. In the present embodiment, the fire alarm 1 further includes a control unit 4, a storage unit 5, an alarm unit 6, and a power supply unit 7, as shown in FIG. The fire alarm 1 is configured so that each component is operated by the power supply from the power supply unit 7 provided inside. However, the fire alarm 1 may be supplied with electric power from an external power source.

The CO sensor 2 detects the concentration of carbon monoxide contained in the environmental atmosphere of the place where the fire alarm 1 is installed. In the present embodiment, the CO sensor 2 is communicably connected to the control unit 4 and detects the carbon monoxide concentration together with the control unit 4, as shown in FIG. The CO sensor 2 detects carbon monoxide contained in the environmental atmosphere and transmits an output value corresponding to the carbon monoxide concentration to the control unit 4. The control unit 4 calculates the carbon monoxide concentration from the received output value. Although the CO sensor 2 is configured separately from the control unit 4 in this embodiment, it may be integrated with the control unit 4.

The CO sensor 2 is an electrochemical gas sensor in this embodiment. Since the electrochemical gas sensor has low power consumption, the power consumption of the fire alarm 1 can be suppressed. Further, when the fire alarm 1 uses a battery as the power supply unit 7, the power consumption is low, so that it is suitable for long-term use. The CO sensor 2, which is an electrochemical gas sensor, detects a current value corresponding to the carbon monoxide concentration by utilizing the oxidation reaction of carbon monoxide, and transmits an output value corresponding to the current value to the control unit 4. However, the CO sensor 2 is not limited to the electrochemical gas sensor as long as it can detect the carbon monoxide concentration in the environmental atmosphere, and may be another gas sensor such as a semiconductor gas sensor or a contact combustion gas sensor. not.

The smoke sensor 3 detects the smoke concentration contained in the environmental atmosphere of the place where the fire alarm 1 is installed. In the present embodiment, the smoke sensor 3 is communicably connected to the control unit 4 and detects the smoke concentration together with the control unit 4, as shown in FIG. The smoke sensor 3 detects smoke contained in the environmental atmosphere and transmits an output value corresponding to the smoke concentration to the control unit 4. The control unit 4 calculates the smoke concentration from the received output value. Although the smoke sensor 3 is configured separately from the control unit 4 in this embodiment, it may be integrated with the control unit 4.

The smoke sensor 3 is a scattered light type smoke sensor in this embodiment. The smoke sensor 3, which is a scattered light type smoke sensor, includes a light emitting unit and a light receiving unit (not shown). The smoke sensor 3 detects a current value corresponding to the smoke concentration generated when the light receiving unit receives the scattered light generated by scattering the light from the light emitting unit by smoke particles, and controls the output value corresponding to the current value. It is transmitted to the part 4. However, the smoke sensor 3 is not limited to the scattered light type smoke sensor as long as it can detect the smoke concentration contained in the environmental atmosphere, and may be another type of smoke sensor.

The control unit 4 calculates the carbon monoxide concentration and the smoke concentration based on the output values from the CO sensor 2 and the smoke sensor 3. Further, the control unit 4 has an arithmetic processing function for performing the processing described below. As shown in FIG. 1, the control unit 4 is communicably connected to the CO sensor 2 and the smoke sensor 3, controls the operation of the CO sensor 2 and the smoke sensor 3, and is obtained by the CO sensor 2 and the smoke sensor 3. Receives the output value. Further, in the present embodiment, the control unit 4 is communicably connected to the storage unit 5 and the alarm unit 6, controls the operation of each component, and is configured to be able to transmit and receive information to each component. ing. The control unit 4 can be configured by using, for example, a known central processing unit (CPU) or the like.

The storage unit 5 stores information about carbon monoxide and smoke. As shown in FIG. 1, the storage unit 5 is communicably connected to the control unit 4 and is configured to communicate information about carbon monoxide and smoke with the control unit 4. The information regarding carbon monoxide and smoke referred to here includes, for example, the output values from the CO sensor 2 and the smoke sensor 3, the carbon monoxide concentration and the smoke concentration calculated from the output values from the CO sensor 2 and the smoke sensor 3. The relational expression (calibration line) between the output value of the CO sensor 2 and the carbon monoxide concentration obtained in advance, and the relational expression (calibration line) between the output value of the smoke sensor 3 and the smoke concentration obtained in advance. ), Carbon monoxide warning threshold, smoke warning threshold, carbon monoxide hemoglobin (COHb) concentration in blood calculated from the detected carbon monoxide concentration, carbon monoxide hemoglobin concentration threshold, and the like. Further, the storage unit 5 may be configured to store a program, a calculation formula, or the like capable of executing the process described below. The storage unit 5 is not particularly limited, and may be configured by a known volatile memory such as RAM or a known non-volatile memory such as a hard disk or flash memory.

The alarm unit 6 issues an alarm when the smoke concentration exceeds a predetermined smoke alarm threshold value. Further, the alarm unit 6 may issue an alarm when the carbon monoxide concentration exceeds a predetermined carbon monoxide alarm threshold value. As shown in FIG. 1, the alarm unit 6 is communicably connected to the control unit 4 and issues an alarm under the control of the control unit 4. The alarm unit 6 is not particularly limited, and is composed of LED lighting, a speaker, or the like, and emits an alarm such as LED lighting or a warning sound.

Next, the operation of the fire alarm 1 of the present embodiment will be described with reference to FIGS. 3 to 8. FIG. 3 is a flowchart schematically showing the main step MS carried out by the fire alarm 1. FIG. 4 is a flowchart schematically showing the sub-step SS1 performed in the main step MS of FIG. 5 to 8 are flowcharts schematically showing sub-steps SS2 to SS5 arbitrarily performed in the sub-step SS1 of FIG. 4, respectively. Substeps SS2 to SS5 may not be carried out, any one may be carried out, or any one or more thereof may be carried out in combination. The operations described below are not limited to the order in which they are described, and may be performed in an order different from the order in which they are described.

The fire alarm 1 is configured to perform the main step MS, as shown in FIG. In the fire alarm 1, the smoke concentration detected by the smoke sensor 3 by the main step MS is a predetermined smoke alarm threshold value (when the smoke alarm threshold value is lowered as described later, the lowered smoke alarm threshold value, or less. It is configured to issue an alarm when the amount exceeds the same). In the present embodiment, the smoke sensor 3 of the fire alarm 1 detects smoke in the environmental atmosphere and transmits an output value corresponding to the smoke concentration to the control unit 4 of the fire alarm 1. The control unit 4 receives the output value from the smoke sensor 3, and calculates the smoke concentration from the output value using the relational expression between the output value stored in the storage unit 5 and the smoke concentration. Thereby, the fire alarm 1 detects the smoke concentration (MS1). Next, the control unit 4 determines whether or not the detected smoke concentration exceeds a predetermined smoke alarm threshold value (MS2). The control unit 4 operates the alarm unit 6 to issue a fire alarm when the smoke concentration exceeds a predetermined smoke alarm threshold value (MS3). As a result, a person in an environment in which the fire alarm 1 is installed can recognize that a fire may have occurred. When the smoke concentration does not exceed a predetermined smoke alarm threshold value, the control unit 4 repeats the process from the beginning of the main step MS. After issuing the fire alarm, the control unit 4 may stop the fire alarm if a predetermined condition is satisfied. The predetermined condition referred to here is not particularly limited, but for example, when the smoke concentration drops below the predetermined smoke warning threshold value, or when the smoke concentration falls below the predetermined smoke warning threshold value, the predetermined time is used. An example is the case where the value exceeds. When the fire alarm is stopped, the control unit 4 executes the main step MS as usual. The fire alarm 1 may be configured to store the detected smoke concentration in time series.

The smoke warning threshold value referred to here is a smoke concentration that serves as a reference when it is determined that a fire may have occurred. The predetermined smoke alarm threshold value is not particularly limited, and can be appropriately set according to the smoke concentration at which it can be determined that a fire has occurred in the environment in which the fire alarm device 1 is installed. The predetermined smoke warning threshold can be set to, for example, 10% / m, which is defined as two types in the "Ministerial Ordinance for Establishing Technical Standards for Residential Disaster Prevention Alarms and Residential Disaster Prevention Notification Equipment".

As shown in FIG. 3, the fire alarm 1 is configured to carry out the sub-step SS1 in the above-mentioned main step MS. As shown in FIG. 4, the fire alarm 1 calculates the carbon monoxide hemoglobin concentration in the blood from the carbon monoxide hemoglobin concentration detected by the CO sensor 2 by the substep SS1, and the calculated carbon monoxide hemoglobin is calculated. It is configured to lower the smoke warning threshold when the concentration exceeds a predetermined carbon monoxide hemoglobinometry threshold. In the present embodiment, the CO sensor 2 of the fire alarm 1 detects carbon monoxide in the environmental atmosphere and transmits an output value corresponding to the carbon monoxide concentration to the control unit 4 of the fire alarm 1. The control unit 4 receives the output value from the CO sensor 2, and calculates the carbon monoxide concentration from the output value using the relational expression between the output value stored in the storage unit 5 and the carbon monoxide concentration. do. Thereby, the fire alarm 1 detects the carbon monoxide concentration (SS11). Here, the fire alarm 1 may be configured to store the detected carbon monoxide concentration in time series. In the present embodiment, the control unit 4 transmits the calculated carbon monoxide concentration to the storage unit 5, and the storage unit 5 stores the carbon monoxide concentration together with the elapsed time from the start of measurement (SS12). Next, the control unit 4 calculates the carbon monoxide hemoglobin concentration in human blood from the detected carbon monoxide concentration (SS13). The control unit 4 determines whether or not the calculated carbon monoxide hemoglobin concentration exceeds a predetermined carbon monoxide hemoglobin concentration threshold value (SS14). When the carbon monoxide hemoglobin concentration exceeds a predetermined carbon monoxide hemoglobin concentration threshold value, the control unit 4 lowers the smoke alarm threshold value (SS15) and ends the sub-step SS1. On the other hand, when the carbon monoxide hemoglobin concentration does not exceed a predetermined carbon monoxide hemoglobin concentration threshold value, the control unit 4 ends the sub-step SS1. At this time, if the smoke warning threshold value has already been lowered, the control unit 4 returns the lowered smoke warning threshold value to the original value. When the control unit 4 finishes the sub-step SS1, the control unit 4 carries out the processing after the main step MS described above.

The carbon monoxide hemoglobin concentration referred to here is the concentration of carbon monoxide hemoglobin estimated to be produced in the blood of a human being in the environment where the fire alarm 1 is installed. .. The carbon monoxide hemoglobin concentration can be determined (estimated) according to the time when a human is exposed to carbon monoxide and the carbon monoxide concentration at that time. The carbon monoxide hemoglobin concentration is not particularly limited, and is, for example, the relationship between the carbon monoxide hemoglobin concentration and the exposure time obtained experimentally or empirically and the carbon monoxide hemoglobin concentration in human blood. It can also be obtained from the known formula reported in "Danger of combustion (oxygen-deficient combustion) in a room with low ventilation rate of household gas appliances" (Safety Engineering Vol. 19 No. 4 (1980) ". It can be calculated by using it, or it can be calculated by using a newly prepared formula based on such a known formula. When the above formula is used to calculate the carbon monoxide hemoglobin concentration, the environment The oxygen concentration contained in the atmosphere is also required. At that time, the oxygen concentration normally present in the air may be adopted as the oxygen concentration, or it may be detected by an oxygen sensor arbitrarily provided in the fire alarm 1. Oxygen concentration may be adopted.

In addition, the carbon monoxide hemoglobin concentration threshold referred to here may mean that the function of a human being in the environment where the fire alarm 1 is installed is impaired, and that the human being may be hindered from escaping from the environment. It is the concentration of carbon monoxide hemoglobin that is the standard when it is judged that there is. The predetermined carbon monoxide hemoglobin concentration threshold value is not particularly limited, and can be appropriately set according to the carbon monoxide hemoglobin concentration at which it can be determined that the human function is impaired. In general, when the carbon monoxide hemoglobin concentration exceeds 10%, mild headache and dilation of subcutaneous blood vessels occur, and when the carbon monoxide hemoglobin concentration exceeds 20%, headache and cranial beating occur, and carbon monoxide occurs. It is said that when the carbon hemoglobin concentration exceeds 30%, severe headache, dizziness, blurred vision, vomiting, and change of lip / skin mucosa to pinkish red occur. The predetermined carbon monoxide hemoglobin concentration threshold is set to 10%, for example, for mild headaches and dilation of subcutaneous blood vessels, in consideration of functional deterioration that can hinder human escape from the environment in which the fire alarm 1 is installed. can do.

Further, lowering the smoke warning threshold value here means resetting the smoke warning threshold value to a value lower than the preset smoke warning threshold value. The smoke warning threshold that is reset to a low value may be at least lower than the preset smoke warning threshold, and is not particularly limited. It can be set to 5% / m, which is stipulated as a type in the "Ministry Ordinance that Establishes Standards".

As shown above, the fire alarm 1 is lower than the preset smoke alarm threshold when the carbon monoxide hemoglobin concentration calculated from the carbon monoxide concentration exceeds a predetermined carbon monoxide hemoglobin concentration threshold. A smoke alarm threshold is set, and is configured to issue an alarm when the smoke concentration is higher than the smoke alarm threshold set lower. Therefore, a person in an environment (fire site) where the fire alarm 1 is installed can recognize the occurrence of a fire and start escaping at a stage where the smoke concentration is relatively low even in a state where functional failure may occur. Therefore, the delay in escaping from the fire site is suppressed. Further, by lowering the smoke warning threshold only when there is a high possibility that the human function is deteriorated, it is possible to improve the accuracy of fire detection while suppressing the occurrence of false alarms.

Here, a specific example of the main step MS including the above-mentioned sub-step SS1 will be described with reference to FIG. 9. FIG. 9 shows a fire provided on the ceiling C when the futon D on the floor surface F is burned by the fire source (heater) H in the room R to cause a smoky fire as shown in FIG. It shows the time change of the carbon monoxide concentration, the carbon monoxide hemoglobin concentration and the smoke concentration obtained by the alarm device 1. With reference to FIG. 9, it can be seen that the carbon monoxide concentration starts to increase from about 15 minutes after the start of driving the fire source H, and the carbon monoxide hemoglobin concentration also starts to increase accordingly. On the other hand, the smoke concentration starts to increase from about 50 minutes after the start of driving the fire source H. For example, when the preset smoke alarm threshold value is 10% / m, if the above-mentioned sub-step SS1 is not performed, the smoke concentration exceeds the smoke alarm threshold value about 74 minutes after the start of driving the fire source H. , An alarm is issued. For example, when the above-mentioned sub-step SS1 is carried out with the carbon monoxide hemoglobin concentration threshold set to 10%, the carbon monoxide hemoglobin concentration becomes the carbon monoxide hemoglobin concentration approximately 54 minutes after the start of driving the fire source H. Beyond the threshold, the smoke warning threshold is lowered. For example, if the lowered smoke warning threshold is set to 5% / m, the smoke concentration will exceed the already lowered smoke warning threshold about 70 minutes after the start of driving the fire source H, and an alarm will be issued at this point. Will be. That is, according to the fire alarm 1 of the present embodiment, when there is a possibility that the human function is deteriorated, the alarm is issued about 4 minutes earlier than usual. As a result, a person in an environment (fire site) where the fire alarm 1 is installed can recognize the occurrence of a fire and start escaping at a stage where the smoke concentration is low even in a state where a malfunction may occur. , Delayed escape from the fire scene is suppressed.

As described above, the fire alarm 1 may be configured to carry out any one or more of the substeps SS2 to SS5 in the substep SS1 of the main step MS. For example, the fire alarm 1 may be configured to perform substep SS2 in substep SS1, as shown in FIG. As shown in FIG. 5, the fire alarm 1 is configured to issue an alarm by substep SS2 when the carbon monoxide concentration detected by the CO sensor 2 exceeds a predetermined carbon monoxide alarm threshold. .. In this embodiment, as shown in FIG. 4, the fire alarm 1 detects the carbon monoxide concentration in the sub-step SS1 (SS11). Next, as shown in FIG. 5, the control unit 4 of the fire alarm 1 determines whether or not the detected carbon monoxide concentration exceeds a predetermined carbon monoxide warning threshold in the substep SS2. (SS21). When the carbon monoxide concentration exceeds a predetermined carbon monoxide alarm threshold value, the control unit 4 operates the alarm unit 6 to issue a CO alarm (SS22). As a result, a person in an environment in which the fire alarm 1 is installed can recognize that a fire may have occurred. For example, when a flame does not occur as in a smoked fire, smoke may be generated much later than the generation of carbon monoxide (see, for example, FIG. 9). Even in such a case, a person in an environment where the fire alarm 1 is installed recognizes a fire at an early stage by issuing an alarm when the carbon monoxide concentration exceeds a predetermined carbon monoxide alarm threshold. be able to. When the carbon monoxide concentration does not exceed the predetermined carbon monoxide alarm threshold value, the control unit 4 ends the sub-step SS2 and carries out the processing after the sub-step SS1. After issuing the CO alarm, the control unit 4 may stop the CO alarm if a predetermined condition is satisfied. The predetermined conditions referred to here are not particularly limited, but for example, when the carbon monoxide concentration drops below the predetermined carbon monoxide warning threshold, or when the carbon monoxide concentration is a predetermined carbon monoxide warning. An example is the case where the time to be equal to or less than the threshold time exceeds a predetermined time. When the CO alarm is stopped, the control unit 4 ends the sub-step SS2 and carries out the processing after the sub-step SS1.

The carbon monoxide warning threshold value referred to here is a carbon monoxide concentration that serves as a reference when determining that a fire may have occurred. The predetermined carbon monoxide warning threshold value is not particularly limited, and can be appropriately set according to the carbon monoxide concentration at which it can be determined that a fire has occurred in the environment in which the fire alarm 1 is installed. The predetermined carbon monoxide alarm threshold can be set to, for example, 100 ppm.

The fire alarm 1 may be configured to perform substep SS3 in substep SS1, as shown in FIG. As shown in FIG. 6, the fire alarm 1 has a carbon monoxide hemoglobin concentration from the time when the carbon monoxide concentration detected by the CO sensor 2 by the substep SS3 exceeds a predetermined carbon monoxide threshold. It is configured to start the calculation. In this embodiment, as shown in FIG. 4, the fire alarm 1 detects the carbon monoxide concentration in the sub-step SS1 (SS11). Next, as shown in FIG. 6, the control unit 4 of the fire alarm 1 determines whether or not the carbon monoxide hemoglobin concentration calculation process is continuing in the sub-step SS3 (SS31). That is, the control unit 4 determines whether or not the carbon monoxide hemoglobin concentration calculation process was performed at the time of the previous detection of the carbon monoxide concentration. If the carbon monoxide hemoglobin concentration calculation process is ongoing, the control unit 4 ends the sub-step SS3 and carries out the process after the sub-step SS1 (the carbon monoxide hemoglobin concentration calculation process). If the carbon monoxide hemoglobin concentration calculation process is not ongoing, the control unit 4 determines whether or not the detected carbon monoxide concentration exceeds a predetermined carbon monoxide threshold value (SS32). When the carbon monoxide concentration exceeds a predetermined carbon monoxide threshold, the control unit 4 ends the sub-step SS3 and carries out the processing after the sub-step SS1 (calculation processing of the carbon monoxide hemoglobin concentration). By starting the calculation process of the carbon monoxide hemoglobin concentration when the carbon monoxide concentration exceeds the predetermined carbon monoxide threshold in this way, the increase in the carbon monoxide hemoglobin concentration is not substantially affected. It is possible to exclude the measurement data of the carbon monoxide concentration, thereby accurately calculating the carbon monoxide hemoglobin concentration. When the carbon monoxide concentration does not exceed the predetermined carbon monoxide threshold value, the control unit 4 ends the sub-step SS1 and carries out the processing after the main step MS.

The carbon monoxide threshold referred to here is the concentration of carbon monoxide that is a standard for determining that it may affect the increase in the concentration of carbon monoxide hemoglobin in human blood. The predetermined carbon monoxide threshold value is not particularly limited, and is appropriately set according to the carbon monoxide concentration that can be judged to have a possibility of affecting the increase in the carbon monoxide hemoglobin concentration in human blood. be able to. The predetermined carbon monoxide threshold value can be set to a value lower than, for example, a predetermined carbon monoxide alarm threshold value which is a reference for issuing an alarm, and can be set to, for example, 50 ppm.

The fire alarm 1 may be configured to carry out substep SS4 in substep SS1, as shown in FIG. As shown in FIG. 7, the fire alarm 1 sets a predetermined time when the duration for which the carbon monoxide concentration detected by the CO sensor 2 is equal to or less than the predetermined value by the sub-step SS4 exceeds the predetermined time. It is configured so that the carbon monoxide hemoglobin concentration calculated up to the lapse of time is set to zero and the lowered smoke alarm threshold is returned to the original value. In this embodiment, as shown in FIG. 4, the fire alarm 1 detects the carbon monoxide concentration in the sub-step SS1 (SS11). Next, as shown in FIG. 7, the control unit 4 of the fire alarm 1 determines whether or not the carbon monoxide concentration is equal to or less than a predetermined value in the sub-step SS4 (SS41). When the carbon monoxide concentration is equal to or less than the predetermined value, the control unit 4 performs the following further processing, and when the carbon monoxide concentration exceeds the predetermined value, the sub-step SS4 is terminated and the sub-step SS1 Perform the subsequent processing. When the carbon monoxide concentration is not more than a predetermined value, the control unit 4 determines whether or not the duration of the carbon monoxide concentration being not more than the predetermined value exceeds the predetermined time (SS42). When the duration exceeds the predetermined time, the control unit 4 sets the carbon monoxide hemoglobin concentration calculated by the time when the predetermined time has elapsed to zero, and lowers the smoke warning threshold when the predetermined time has elapsed. The smoke warning threshold is returned to the original value (SS43). Then, the control unit 4 ends the sub-step SS1 and carries out the processing after the main step MS. On the other hand, when the duration in which the carbon monoxide concentration is equal to or less than the predetermined value does not exceed the predetermined time, the control unit 4 ends the sub-step SS4 and carries out the processing after the sub-step SS1. If the carbon monoxide concentration is below the predetermined value and the duration exceeds the predetermined time, it is highly possible that the carbon monoxide hemoglobin concentration in human blood has decreased. In such a case, by setting (resetting) the carbon monoxide hemoglobin concentration to zero, the carbon monoxide hemoglobin concentration in human blood can be calculated (estimated) more accurately when the carbon monoxide concentration rises again. be able to. Further, when the smoke warning threshold value is lowered, the occurrence of false alarms can be suppressed by returning the smoke warning threshold value to the original value.

The predetermined value with respect to the carbon monoxide concentration is the concentration of carbon monoxide as a reference when it is judged that the increase in the carbon monoxide hemoglobin concentration in human blood is not affected. The predetermined value is not particularly limited, and can be appropriately set according to the carbon monoxide concentration that can be determined not to affect the increase in the carbon monoxide hemoglobin concentration in human blood. The predetermined value can be set to a value lower than, for example, a predetermined carbon monoxide alarm threshold value which is a standard for issuing an alarm, and more specifically, for example, one in the indoor air in the building environmental hygiene management standard. It can be set to 10 ppm, which is the standard for carbon oxide concentration.

In addition, the predetermined time for the duration when the carbon monoxide concentration is below the predetermined value means that the carbon monoxide hemoglobin concentration in human blood has recovered (decreased) to a level at which human functional deterioration does not occur. This is the reference time when making assumptions. The predetermined time is not particularly limited, and is appropriately set according to the time during which it can be assumed that the carbon monoxide hemoglobin concentration in human blood has recovered (decreased) to a level at which human functional deterioration does not occur. can do. The predetermined time can be set, for example, from several minutes to several hours (for example, 3 to 4 hours when the half-life of carbon monoxide hemoglobin is adopted).

The fire alarm 1 may be configured to correct the calculated carbon monoxide hemoglobin concentration according to the distance between the assumed fire occurrence location and the installation location where the fire alarm is installed. Then, the fire alarm 1 may be configured to lower the smoke alarm threshold when the corrected carbon monoxide hemoglobin concentration exceeds a predetermined carbon monoxide hemoglobin concentration threshold. In the present embodiment, as shown in FIG. 4, the control unit 4 of the fire alarm 1 determines whether or not the calculated carbon monoxide hemoglobin concentration exceeds a predetermined carbon monoxide hemoglobin concentration threshold in the substep SS1. Is determined (SS14). The control unit 4 implements the sub-step SS5 shown in FIG. 8 instead of the processing SS14. The control unit 4 corrects the carbon monoxide hemoglobin concentration calculated in substep SS5 according to the distance between the assumed fire occurrence location and the installation location where the fire alarm is installed (SS51). Then, the control unit 4 determines whether or not the corrected carbon monoxide hemoglobin concentration exceeds a predetermined carbon monoxide hemoglobin concentration threshold value (SS52). When the corrected carbon monoxide hemoglobin concentration exceeds a predetermined carbon monoxide hemoglobin concentration threshold value, the control unit 4 ends sub-step SS5 and returns to sub-step SS1 to lower the smoke warning threshold value (SS15). When the corrected carbon monoxide hemoglobin concentration does not exceed the predetermined carbon monoxide hemoglobin concentration threshold, the control unit 4 returns the corrected carbon monoxide hemoglobin concentration to the original carbon monoxide hemoglobin concentration and substeps. The process after SS1 is terminated and the main step MS is performed.

Here, the fire alarm 1 is generally installed on the ceiling or wall of the room. On the other hand, the place where the fire occurs is often the floor surface in the room or its surroundings, for example, a fire caused by the mismanagement of cigarettes. The concentration of carbon monoxide near the location of the fire may be higher than the concentration of carbon monoxide near the ceiling or walls away from the location of the fire. Along with this, the carbon monoxide hemoglobin concentration in the blood of humans near the place where the fire occurred is the carbon monoxide hemoglobin concentration calculated based on the concentration of carbon monoxide detected at a place away from the place where the fire occurred. May be higher than. For example, FIG. 10 shows the carbon monoxide concentration and monoxide due to the difference in the installation location between the fire alarm 1 installed near the fire source H and the fire alarm 1 installed on the ceiling C as shown in FIG. It shows the difference in the time change of the carbon hemoglobin concentration. In the fire alarm 1 installed near the fire source H, carbon monoxide is detected earlier than the fire alarm 1 installed in the ceiling C away from the fire source H. High carbon concentration. Along with this, the carbon monoxide hemoglobin concentration near the fire source H starts to rise faster than the carbon monoxide hemoglobin concentration near the ceiling C, and becomes higher. In this way, if a fire alarm is installed at a position away from the fire location, there is a possibility that the carbon monoxide hemoglobin concentration in the blood of humans near the fire location will be calculated (estimated) small. be. On the other hand, as described above, a fire occurs by correcting the calculated carbon monoxide hemoglobin concentration according to the distance between the assumed fire occurrence location and the installation location where the fire alarm is installed. It is possible to more accurately estimate the concentration of carbon monoxide hemoglobin in the blood of humans near the location. Then, by changing the smoke alarm threshold based on the corrected carbon monoxide hemoglobin concentration, it is possible to issue a fire alarm more accurately and more reliably suppress the escape delay of a person near the place where the fire occurred. be able to.

The correction of carbon monoxide hemoglobin concentration is based on the distance between the assumed location of the fire and the location where the fire alarm is installed. For example, it is known that the carbon monoxide concentration changes depending on the horizontal and vertical distances from the fire location when there is a fire location in the room. Therefore, the carbon monoxide hemoglobin concentration can be corrected according to the horizontal and vertical distances between the assumed fire occurrence location and the installation location where the fire alarm is installed. For example, carbon monoxide hemoglobin concentration based on the relationship between the carbon monoxide hemoglobin concentration at the actual location of the fire (or its vicinity) and the carbon monoxide hemoglobin concentration at the location where the fire alarm 1 is installed, which is required experimentally or empirically. A correction formula for correcting the hemoglobin concentration can be obtained. The correction formula can also be constant with respect to the distance if the distance between the assumed fire occurrence location and the installation location where the fire alarm is installed is within a certain range. Further, in the present embodiment, when correcting the carbon monoxide hemoglobin concentration, the distance between the assumed fire occurrence location and the installation location where the fire alarm is installed is adopted, but the actual value obtained from a thermal sensor or the like is adopted. The distance between the location of the fire and the location where the fire alarm is installed may be adopted.

In this embodiment, the calculated carbon monoxide hemoglobin concentration is corrected in substep SS5. However, even if the carbon monoxide hemoglobin concentration threshold value is corrected instead of the calculated carbon monoxide hemoglobin concentration being corrected, the same effect as the above effect is obtained. Further, the change from the determination process SS14 in the sub-step SS1 to the sub-step SS5 can be performed, for example, by switching with a switch provided in the fire alarm 1 when the fire alarm 1 is installed.

1 Fire alarm 2 CO sensor 3 Smoke sensor 4 Control unit 5 Storage unit 6 Alarm unit 7 Power supply unit C Ceiling D Duvet F Floor surface H Fire source MS Main step R room SS1, SS2, SS3, SS4, SS5 Substep

Claims (5)

It is equipped with a CO sensor that detects the concentration of carbon monoxide contained in the environmental atmosphere and a smoke sensor that detects the concentration of smoke contained in the environmental atmosphere.
A fire alarm configured to issue an alarm when the smoke concentration detected by the smoke sensor exceeds a predetermined smoke alarm threshold value.
The fire alarm calculates the carbon monoxide hemoglobin concentration in blood from the carbon monoxide concentration detected by the CO sensor, and the calculated carbon monoxide hemoglobin concentration exceeds a predetermined carbon monoxide hemoglobin concentration threshold. Is configured to lower the smoke alarm threshold.
Fire alarm. The fire alarm corrects the calculated carbon monoxide hemoglobin concentration according to the distance between the assumed fire occurrence location and the installation location where the fire alarm is installed, and the corrected carbon monoxide. It is configured to lower the smoke alarm threshold when the hemoglobin concentration exceeds the predetermined carbon monoxide hemoglobin concentration threshold.
The fire alarm according to claim 1. The fire alarm is described from the time when the carbon monoxide concentration detected by the CO sensor exceeds a predetermined carbon monoxide threshold lower than a predetermined carbon monoxide alarm threshold as a reference for issuing an alarm. Configured to initiate the calculation of carbon monoxide hemoglobin concentration,
The fire alarm according to claim 1 or 2. When the duration for which the carbon monoxide concentration detected by the CO sensor is equal to or less than a predetermined value exceeds a predetermined time, the fire alarm has a carbon monoxide hemoglobin concentration calculated by the time when the predetermined time has elapsed. Is set to zero, and the smoke alarm threshold that has been lowered is configured to return to the original value.
The fire alarm according to any one of claims 1 to 3. The fire alarm is configured to issue an alarm when the carbon monoxide concentration detected by the CO sensor exceeds a predetermined carbon monoxide alarm threshold.
The fire alarm according to any one of claims 1 to 4.

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