JP2004341661A - Fire alarm and fire deciding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fire alarm improved for detecting the occurrence of a fire or the abnormal increase of CO density or smoke density in an early stage, and for minimizing any erroneous report as much as possible assuming that this fire alarm is set in a general housing. <P>SOLUTION: The fire alarm 1 is provided with an alarm part 7 for generating an alarm, a sensor 2 for detecting a temperature, a sensor 3 or 4 for detecting either CO or smoke, a deciding part 63 for comparing a detection value obtained by the sensor 3 or 4 with a set threshold, and for controlling an alarm part to generate an alarm when the predetermined comparison result continues in a set duration time and a decision condition setting part 62 for changing the setting of either the threshold or the duration time based on a detection value detected by the sensor 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fire alarm installed in a general house, and more particularly to a fire alarm improved to detect a fire or an abnormal increase in CO concentration or smoke concentration at an early stage and to minimize false alarms. About. Further, the present invention relates to a fire determination method used in such a fire alarm.
[0002]
[Prior art]
First, the present situation of fires in houses (including detached houses and apartment houses) will be described. Fire deaths amount to about 1,000 people in one year, and over 80% of them are caused by house fires. 40% of the direct causes of death are poisoning and suffocation by CO (carbon monoxide), and 3.5% are burns. However, a significant proportion of those caused by burns are thought to be firstly motor dysfunctional due to CO poisoning, resulting in immobility and being burned late by escape.
[0003]
80% of the death sites are living rooms (including bedrooms). On the other hand, about 10% of kitchens use fire most. This is because most of the fires in the kitchen cause the residents to wake up and perform activities (cooking), so that they can perform fire fighting activities or escape. However, in the case of a living room, especially a bedroom, the occupant may be sleeping, and their activity ability is reduced.
[0004]
Also, 20% of the ignited materials are futons and 10% are clothing, and these two occupy the first and second places of the ignited materials. The state in which futons and clothing are smoked and burned is called smoking. And 20% of ignition sources are tobacco, and 1.5% are stoves. In the case of sleeping tobacco, first, a futon or clothing is ignited and smoked. In the case of smoldering, it is hard to notice the occurrence of fire because almost no flame is emitted, but the smoke and CO concentration are gradually increasing. Then, during this smoking, the CO concentration increases, causing CO poisoning. In particular, in the case of sleeping while smoking while being drunk, it is easy to notice that a fire has occurred due to sickness, and it is not easy to move immediately, so escape is likely to be delayed.
[0005]
In view of such a situation, it can be said that it is highly necessary to install a fire alarm in a living room. However, at present, the prevalence of fire alarms in living rooms is equal to zero. Fire alarms must be installed in office buildings and large-scale apartment buildings in accordance with the Fire Services Act. The penetration rate has not been raised because it has not been done.
[0006]
As a detection method used in the fire alarm, there are a single method such as a thermal method, a smoke method, a flame method, and the like, or a compound method combining a plurality of methods. In the stand-alone type, the value of the temperature in the case of the thermal type, the amount of extinction rate conversion in the case of the smoke type, and the amount of received ultraviolet or infrared light in the case of the flame type must be equal to or higher than the set level value (threshold). If an alarm occurs. Further, there is a compound type that uses a product of a plurality of detected values (for example, temperature × dimming conversion amount) (for example, see Patent Document 1).
[0007]
Conventionally, a single smoke alarm has been recommended for all fires except for kitchen fires. A typical smoke-type fire alarm currently used is one in which a light-emitting element and a light-receiving element are arranged in a casing whose inner surface is painted black. When smoke enters the casing, light is scattered by the smoke, and the scattered light is detected to report the generation of smoke.
[0008]
When a smoke-type fire alarm is installed in a living room, cotton dust and dust accumulate on the inner surface of the casing, and the light is reflected by such deposits to emit scattered light, thereby generating false reports. Sometimes. In addition, it may react to cigarette smoke and cause false alarms. In the kitchen, it is not permitted to install a smoke-type fire alarm because it reacts to smoke and water vapor generated during cooking of grilled fish and the like.
[0009]
On the other hand, an alarm device that detects CO generated together with smoke when a fire occurs and issues an alarm when the CO concentration exceeds a threshold has been proposed in ISO. The threshold value of the CO concentration is determined based on the experiment of the fire test standard TF3 of the EU, and the threshold value is a considerably low value of 50 ppm or less. When the CO concentration threshold is set to 50 ppm, since the CO concentration generated from daily used burning appliances (combustion appliances such as gas stoves and kerosene fan heaters) can be higher than this value. In such a case, there is a possibility that an alarm is issued only by using such a burning appliance.
[0010]
That is, since the CO concentration in the atmosphere of the room is different depending on whether or not the combustion device is operating in the room where the alarm is installed, if the threshold of the CO concentration set in the alarm is fixed, As described above, a false alarm may occur. Therefore, when installing a CO detection type fire alarm in a living room, it is necessary to determine an appropriate CO concentration threshold value to be set in the fire alarm in consideration of the environment of the room. In addition to the operation of the combustion apparatus, it is expected that the temperature, CO concentration, and smoke concentration in the room will differ depending on whether or not there is an electric heat source, whether or not there is an air conditioner, and whether or not there is a person who smokes a cigarette.
[0011]
[Patent Document 1]
JP 2001-216579 A
[0012]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and supposes that it will be installed in a general house (particularly a single-family house). It is an object of the present invention to provide a fire alarm which can be detected and is improved so that false alarms are reduced as much as possible.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, a fire alarm device according to the present invention is a fire alarm device that reports the occurrence of a fire or an abnormal rise in CO concentration or smoke concentration, and includes an alarm unit that generates an alarm, and a temperature detection unit. A first sensor, a second sensor that detects one of CO and smoke, and a detection value obtained by the second sensor and a set threshold value. A determination unit that controls an alarm unit to generate an alarm when a predetermined comparison result continues over a period of time, and at least one of a threshold value and a duration time based on a detection value obtained by the first sensor. And a determination condition setting unit for changing the setting of (1).
[0014]
Further, the fire determination method according to the present invention is a method for determining the occurrence of a fire or an abnormal rise in CO concentration or smoke concentration in a fire alarm installed indoors, wherein the temperature is determined using a first sensor. (A) detecting one of CO and smoke using the second sensor, and comparing the detected value obtained by the second sensor with a set threshold value. (B) generating an alarm when the predetermined comparison result continues for a predetermined duration, and setting at least one of a threshold and a duration based on a detection value obtained by the first sensor. Is changed, and the detected value obtained by the second sensor is compared with the changed threshold, and an alarm is generated when the predetermined comparison result continues for the changed duration. Step (d) That.
[0015]
According to the present invention configured as described above, based on the detection value obtained by the first sensor that detects the temperature, at least one of the threshold value and the duration used for determining the CO concentration or the smoke concentration is set. Therefore, it is possible to provide an improved fire alarm which can detect the occurrence of a fire or an abnormal increase in the CO concentration or the smoke concentration at the initial stage, and improve the false alarm as much as possible.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the time-dependent changes in temperature, CO concentration and smoke concentration (dimming conversion rate) in a smoked fire in the early stage of the fire were compared with the time-dependent changes in temperature, CO concentration and smoke concentration in various environments shown below. explain.
(1) In an environment where burning appliances such as gas stoves, oil stoves, and gas fan heaters are operating in the room
(2) In an environment where no burning appliances are operating in the room, but non-burning appliances such as IH cookers, hot plates, floor heaters, and electric stoves are operating as heat sources.
③ Under the environment where smoking is in the room
▲ 4 ▼ Under the environment where the air conditioner installed in the room is operating
[0017]
FIG. 1 is a graph showing (A) a temperature change, (B) a CO concentration change, and (C) a smoke concentration change under a smoldering fire and various conditions.
As shown in FIG. 1, in the case of a smoldering fire, the temperature hardly increases even after the occurrence of the fire, but the CO concentration and the smoke concentration gradually increase after the occurrence of the fire. That is, it can be seen that a smoked fire can be detected by an increase in the CO concentration or smoke concentration. Here, when the time when the CO concentration exceeds the threshold value (for example, 75 ppm) continues for a predetermined time (for example, 3 minutes or more), or when the smoke concentration (light reduction rate conversion amount) becomes the threshold value (for example, 5%). If the excess time continues for a predetermined time (for example, 3 minutes or more), it can be determined that the fire is a smoldering fire. In the following, the threshold value of each density determined in this way is referred to as a reference threshold value, and the reference value of the duration time when each density exceeds the threshold value is referred to as a reference duration time.
[0018]
As this smoldering fire progresses, it shifts to a full-scale fire. FIG. 2 is a graph showing (A) a change in temperature, (B) a change in CO concentration, and (C) a change in smoke concentration when a smoldering fire shifts to a full-scale fire. This graph shows the change over a longer period than the graph of FIG. As shown in FIG. 2A, the temperature change is small during the smoldering fire, but for a certain time t. ₃ After that, the temperature rapidly rises to 50 ° C. or more. Further, as shown in FIG. 2 (B), the CO concentration gradually increases during the smoldering fire, but the CO concentration sharply increases after flaming. Note that the CO concentration falls after being saturated at a certain concentration. Further, as shown in FIG. 2C, the smoke density continues to increase even after the transition from the smoldering fire to a full-scale fire.
[0019]
Referring again to FIG. 1, (1) in an environment in which a combustion stove such as a gas stove is operating in a room, the temperature rapidly rises after a certain time has elapsed since the start of the operation of the combustion stove. To rise. In addition, since CO and smoke are generated by the combustion, the CO concentration and the smoke concentration gradually increase after the operation of the combustion device starts. At this time, the increase rates of the CO concentration and the smoke concentration are larger than those at the time of the smoldering fire. Therefore, the values of the CO concentration and the smoke concentration are also larger than the values at the time of the smoldering fire. That is, when the combustion equipment is operated, the CO concentration and the smoke concentration are equal to or higher than the reference thresholds of these concentrations generated at the time of a smoldering fire. In such a case, a false report will be generated.
[0020]
As shown in FIG. 1, (2) in an environment where a non-burning appliance such as an IH cooker operates as a heat source in a room, the temperature hardly rises even when the non-burning appliance starts operating. The CO and smoke concentrations do not increase at all. (3) In a smoking environment in a room, the temperature does not rise at all. The CO concentration gradually increases after a certain time has elapsed since the start of smoking, and the smoke concentration starts increasing immediately after the start of smoking.
[0021]
On the other hand, in an environment where the air conditioner installed in the room is operating, the temperature rises toward the set temperature after a certain time has elapsed after the air conditioner started operating (in the case of heating operation). Alternatively, the temperature is lowered (in the case of cooling operation) to maintain the set temperature. However, the temperature periodically fluctuates near the set temperature under the influence of the ON / OFF control of the compressor. The CO and smoke concentrations do not increase at all.
[0022]
From FIG. 1, the CO concentration change and the smoke concentration change at the time of a smoldering fire are: (2) the environment where non-burning appliances are operating as a heat source in the room, and (3) the environment where smoking is in the room. Below, (4) it can be seen that the CO concentration change and the smoke concentration change in each of the environments where the air conditioner installed in the room is operating are different. That is, under the environment of (2) to (4), almost no CO is generated. Therefore, when the CO concentration exceeds the reference threshold, it can be determined that a fire has occurred. Further, under the environment of (2) to (4), since the generation of smoke is relatively small, it can be determined that a fire has occurred even if the smoke concentration exceeds the reference threshold. Therefore, in the environment of (2) to (4), no problem occurs even if a uniform judgment is made based on the above-mentioned reference threshold value or reference duration time of the CO concentration or the smoke concentration.
[0023]
However, (1) In an environment where a burning appliance is operating in a room, the CO concentration and the smoke concentration due to CO and smoke generated from the burning appliance are higher than a reference threshold for detecting a smoldering fire. It becomes. For this reason, if the above-mentioned reference threshold value is set in the alarm device in an environment where the combustion appliance is operating, a false report will be generated.
[0024]
Therefore, when the CO concentration or the smoke concentration exceeds a certain value, it is necessary to distinguish whether the concentration is caused by a smoldering fire or by the operation of a burning appliance. As can be seen from FIG. 1, in the case of a smoldering fire, the rate of temperature rise is smaller than in an environment in which the burning appliance is operating. Therefore, when the CO concentration or smoke concentration exceeds a certain value, it is necessary to use the temperature to distinguish whether the CO or smoke is generated by the operation of a burning appliance or by a smoldering fire. It can be said that it is sufficient to see the difference in the change characteristics of.
[0025]
As described above, in an environment where a burning appliance is operating, CO and smoke are increasing even if it is not a smoldering fire. If a smoldering fire occurs in such an environment, there will be more CO and smoke than the amount of CO and smoke generated by the operation of the burning appliance, so that the smoldering fire or the CO concentration or When detecting an abnormal increase in smoke concentration, it is appropriate to raise the threshold values of the CO concentration and the smoke concentration. For example, the CO concentration threshold is increased from 75 ppm to 100 ppm. Also, the smoke density threshold is increased from 5% to 10%.
[0026]
However, raising the threshold in this way also increases the danger to the human body. Therefore, when the threshold is raised, it is desirable to set the duration to be short. For example, the duration of the CO concentration is reduced from 3 minutes to 1 minute. Also, the duration of the smoke density is reduced from 3 minutes to 1 minute. By setting the duration to be short in this way, it is possible to avoid a situation that poses a danger to the human body.
[0027]
Next, a fire alarm according to one embodiment of the present invention will be described. The fire alarm according to the present invention is configured based on the above concept.
FIG. 3 is a block diagram showing a configuration of a fire alarm according to one embodiment of the present invention. As shown in FIG. 3, the fire alarm 1 includes a temperature sensor 2 for detecting the temperature of the indoor atmosphere, a CO sensor 3 for detecting CO in the indoor atmosphere, and a smoke sensor 4 for detecting smoke in the indoor atmosphere. , A changeover switch 5 used to set the installation location of the fire alarm 1, a control unit 6 for judging a fire or the like based on output signals of these sensors, and issuing an alarm according to the judgment result of the control unit 6. An alarm unit 7 and a transmitting / receiving unit 8 for transmitting and receiving signals to and from another fire alarm are provided.
[0028]
Here, one of the CO sensor 3 and the smoke sensor 4 may be omitted. However, by providing both the CO sensor 3 and the smoke sensor 4, it is possible to sufficiently cope with a fire that does not generate much smoke but generates CO, or vice versa. Further, when it is not assumed that a plurality of fire alarms are installed in one house, it is not necessary to provide the transmission / reception unit 8.
[0029]
As the temperature sensor 2, for example, a thermistor, a thermocouple, a semiconductor, or the like can be used. As the CO sensor 3, for example, a sensor of a contact combustion type, a semiconductor type, an electrochemical type, an optical type, or the like can be used. As the smoke sensor 4, for example, a general smoke sensor that measures the amount of reduced light conversion can be used. Output signals from these sensors are sent to the control unit 6.
[0030]
The control unit 6 includes an AD converter 61 that performs AD conversion of output signals of various sensors, a determination condition setting unit 62 that sets determination conditions, and a determination unit 63 that determines the occurrence of a fire or the like according to the set determination conditions. In. The determination condition setting unit 62 and the determination unit 63 are typically realized as functional blocks including a microcomputer and accompanying software (program), but are configured by combining general logic circuits and storage circuits. You may do it.
[0031]
The determination condition setting unit 62 sets a determination condition used in the determination unit 63 based on a detection value or the like obtained by the temperature sensor 2. Further, the fire alarm 1 is provided with a changeover switch 5 used to change the determination condition depending on whether the fire alarm is installed in a kitchen or not. The determination condition setting unit 62 sets the threshold value of the CO concentration or the smoke concentration or the duration according to the setting of the changeover switch 5.
[0032]
Normally, a kitchen is provided with a ventilation fan, and during cooking, the ventilation fan is operated to exchange indoor air. For this reason, it is considered that even if the duration is increased in a state where the thresholds of the CO concentration and the smoke concentration are increased, the influence on the human body is small. Therefore, when the installation location is set to the kitchen by the changeover switch 5, the determination condition setting unit 62 sets the threshold values of the CO concentration and the smoke concentration to be high. Further, when the installation location is set to the kitchen, it is desirable to set the duration to be long. For example, when the installation location is set to the kitchen, the thresholds of the CO concentration and the smoke concentration are doubled and the duration of the CO concentration is five times that when the installation location is set to a living room or the like. And
[0033]
The kitchen is an environment where a lot of smoke and CO gas are generated by burning appliances (such as gas stoves), and it is not possible to install a smoke-type fire alarm. There is also concern that false reports may occur. However, according to the fire alarm according to the present embodiment, since the detection of smoke or the detection of CO is performed in combination with the detection of temperature, the possibility of occurrence of false alarm is reduced. Further, by providing the changeover switch 5 for setting the installation location of the fire alarm, the occurrence of false alarms can be further reduced even when the fire alarm is installed in the kitchen.
[0034]
The determination unit 63 determines whether a fire has occurred or an abnormal increase in the CO concentration or the smoke concentration based on the detection value obtained by the CO sensor 3 or the smoke sensor 4 in accordance with the determination condition set by the determination condition setting unit 62. judge.
[0035]
One specific example of such a determination will be described. The determination condition setting unit 62 sets a threshold value and a duration used in the determination unit 63 based on the detection value obtained by the temperature sensor 2. The determination unit 63 compares the detection value obtained by the CO sensor 3 or the smoke sensor 4 with a set threshold, and issues an alarm when a predetermined comparison result continues for a set duration. The alarm unit 7 is controlled to perform the operation. For example, when the detection value obtained by the CO sensor 3 or the smoke sensor 4 exceeds each threshold for each duration, the determination unit 63 causes the alarm unit 7 to generate an alarm. Here, when the amount of change in the temperature detected by the temperature sensor 2 exceeds the set value X, the determination condition setting unit 62 sets the threshold to be high and the duration to be short.
[0036]
Next, an example of a method of obtaining the amount of change in temperature in the present embodiment will be described.
In the present embodiment, in order to obtain the amount of change in temperature, 15 pieces of temperature data obtained by sampling every minute within the latest 15 minutes are used. First, in order to avoid the effects of temperature peaks and dips caused by the on / off control of the air conditioner, etc., the temperature data having the highest value and the temperature data having the lowest value are selected from the 15 temperature data. And exclude. Then, from the remaining 13 temperature data, the average value (high temperature) T of the top 4 temperature data is obtained. _max4 And the average value (low temperature) T of the lower four temperature data _min4 And ask. Furthermore, high temperature T _max4 And low temperature T _min4 Temperature difference ΔT ₄ Ask for. In the present embodiment, these high temperatures T _max4 , Low temperature T _min4 , Temperature difference ΔT ₄ Is used to change the determination condition as described below.
[0037]
As can be seen from FIG. 1, the rate of temperature rise is small in the case of a smoldering fire, and the rate of temperature rise is high when the combustion equipment is operating. Therefore, when the temperature is rising, the temperature difference ΔT ₄ Is small, it is expected that a smoldering fire occurs and the temperature difference ΔT ₄ If is large, it is expected that the combustion equipment is operating. Therefore, the determination condition setting unit 62 determines that the temperature is rising and determines that the temperature difference ΔT ₄ Is larger than the set value X, the threshold is set higher and the duration is set shorter. For example, the CO concentration threshold is raised from 75 ppm to 125 ppm, and the smoke concentration threshold is raised from 7.5% to 10%. Further, the duration of the CO concentration is reduced from 3 minutes to 1 minute, and the duration of the smoke concentration is also reduced from 1 minute to 0.5 minutes.
[0038]
As a result, the occurrence of a fire is prevented from being erroneously reported by the operation of the combustion appliance. However, when the detection value obtained by the CO sensor 3 or the smoke sensor 4 exceeds the changed threshold value for the changed duration, the CO concentration or the smoke concentration abnormally rises and is dangerous to the human body. In this case, an alarm is generated by the alarm unit 7.
[0039]
In the above determination, it is desirable that the set value X to be compared with the amount of change in temperature be changed depending on whether the temperature rise is due to a combustion appliance or an air conditioner. When the air conditioner is operating, the temperature in the room is controlled so as to become the set value, so it is considered that the room does not become too hot. Therefore, the set value X is changed to the high temperature T _max4 Change according to the value of.
[0040]
For example, high temperature T _max4 If the temperature exceeds 35 ° C., there is a high possibility that the combustion appliance is operating, so the determination condition setting unit 62 sets the set value X to a small value once. As a result, the temperature difference ΔT ₄ Exceeds 1 degree, if it is determined that the temperature is rising, the threshold is set high. On the other hand, high temperature T _max4 If the temperature is equal to or lower than 35 ° C., it is possible that the air conditioner is operating, so the determination condition setting unit 62 sets the set value X to a relatively large value of 2 degrees. As a result, even if it is determined that the temperature is rising, the temperature difference ΔT ₄ The threshold is not set high unless is greater than twice.
[0041]
Here, a method of determining whether or not the temperature is increasing will be described. Of the 15 temperature data obtained by detecting the temperature by the temperature sensor 2, the temperature data having the highest value and the temperature data having the lowest value are excluded from the first 5 temperature data. Average (initial average) T of the three temperature data obtained _P Ask for. Also, of the 15 temperature data, an average value of three temperature data excluding the temperature data having the highest value and the temperature data having the lowest value from the last five temperature data (final period) Average) T _R Ask for.
[0042]
Next, the initial average value T _P And the final average T _R And T _R > T _P In the case of, it is determined that the temperature is increasing within 15 minutes. In an environment where the combustion equipment is operating, the temperature always rises. _R > T _P It becomes. In other words, T _R ≤T _P If it is, it can be said that the burning appliance is not operating. In particular, T _R <T _P Is the case where the air conditioner is operating in the cooling mode. Therefore, T _R ≤T _P In the case of, there is no need to distinguish whether the combustion appliance is operating or the air conditioner is operating, so the set value X is set to a relatively large value to prevent malfunction.
[0043]
When a combustion device that causes incomplete combustion is operating, the temperature rise timing and the CO concentration or smoke concentration rise timing are almost the same, but the smoke is smoked in an environment where the air conditioner is operating. When a fire occurs, the temperature rise timing differs from the CO concentration or smoke concentration rise timing. Therefore, if the temperature rise timing and the CO concentration or smoke concentration rise timing are shifted by a predetermined interval (for example, 15 minutes) or more, the threshold and the duration are not changed, and the standard threshold and the duration are not changed. May be used.
[0044]
FIG. 4 is a flowchart showing the operation of the fire alarm of FIG. Here, a case where the temperature and the CO concentration are detected will be described.
First, in step S1, the temperature data per minute for the latest 15 minutes obtained by the temperature sensor 2 detecting the temperature is processed as described above to obtain the high temperature T. _max4 And the high temperature T _max4 Is 35 ° C. or less. High temperature T _max4 If the temperature is equal to or lower than 35 ° C., the process proceeds to step S2, _max4 If it exceeds 35 ° C., the process moves to step S3.
[0045]
In step S2, the temperature difference ΔT ₄ Is 2 ° C. or less. Temperature difference ΔT ₄ If is less than or equal to 2 ° C., it is determined that the combustion appliance is not operating, and the process proceeds to step S5. On the other hand, the temperature difference ΔT ₄ If the temperature exceeds 2 ° C., it is determined that there is a possibility that the combustion appliance is operating, and the process proceeds to step S4.
[0046]
In step S3, the temperature difference ΔT ₄ Is not more than 1 ° C. Temperature difference ΔT ₄ If is less than or equal to 1 ° C., it is determined that the combustion appliance is not operating, and the process proceeds to step S5. On the other hand, the temperature difference ΔT ₄ If the temperature exceeds 1 ° C., it is determined that there is a possibility that the combustion appliance is operating, and the process proceeds to step S4.
[0047]
In step S4, the initial average value T _P And the final average T _R Compare. T _R > T _P If not, it is determined that the combustion appliance is not operating, and the process proceeds to step S5. On the other hand, T _R > T _P If so, it is determined that the combustion appliance is operating, and the process proceeds to step S15.
[0048]
In step S5, it is determined whether or not the installation location of the fire alarm set by the changeover switch 5 shown in FIG. 3 is a kitchen. If the place where the fire alarm is installed is other than the kitchen (hereinafter referred to as a living room), the process proceeds to step S6, and if the place where the fire alarm is installed is the kitchen, the process proceeds to step S16.
[0049]
In step S6, the threshold value of the CO concentration is set to the reference threshold value for the living room (for example, 75 ppm), and the continuation time is set to the reference continuation time for the living room (for example, 3 minutes). In step S16, the threshold value of the CO concentration is set to the reference threshold value for kitchen (for example, 150 ppm), and the duration is set to the reference duration time for kitchen (for example, 15 minutes).
[0050]
Similarly, in step S15, it is determined whether or not the installation location of the fire alarm set by the changeover switch 5 is the kitchen. If the installation location of the fire alarm is a living room, the process proceeds to step S26, and if the installation location of the fire alarm is a kitchen, the process proceeds to step S36.
[0051]
In step S26, the threshold of the CO concentration is set to a high concentration (for example, 125 ppm) and the duration is set to a short time (for example, one minute) for the living room. In step S36, the threshold value of the CO concentration is set to a high concentration (for example, 250 ppm) and the duration is set to a short time (for example, 5 minutes) for kitchen use.
[0052]
Next, in step S7, it is determined whether or not the detected value of the CO concentration obtained by the CO sensor 3 has exceeded the threshold value set in step S6, S16, S26, or S36. If the detected value of the CO concentration exceeds the threshold, the process proceeds to step S8. If the detected value of the CO concentration does not exceed the threshold, the process returns to step S1.
[0053]
In step S8, it is determined whether or not the time during which the CO concentration is equal to or greater than the threshold is equal to or greater than the duration set in step S6, S16, S26, or S36. If the time during which the CO concentration is equal to or greater than the threshold is equal to or greater than the duration, it is determined that a fire has occurred, and an alarm is issued to the alarm unit 7 in step S9. On the other hand, if the time during which the CO concentration becomes equal to or higher than the threshold does not reach the duration, the process returns to step S1.
[0054]
Here, for example, when food is burned using a hot plate, which is one of the electric heat sources, or when smoking is continued to be smoked, CO or smoke is generated. However, in these cases, since the temperature does not rise so much, the process proceeds to step S6 or S16 in the flowchart shown in FIG. 4, and the threshold of the CO concentration is set to the reference threshold, and the duration is set to the reference duration.
[0055]
Next, a case where a plurality of alarms according to the present embodiment are installed in a plurality of rooms of one house will be described.
As shown in FIG. 3, the fire alarm 1 is provided with a transmission / reception unit 8 for transmitting / receiving a signal to / from another fire alarm installed in another room. The transmission / reception unit 8 transmits a weak RF (radio frequency band) signal to an AC line connected to an outlet of an AC power supply, for example, and transmits the signal from another fire alarm installed in another room. Signals are transmitted and received by receiving RF signals via the AC line. Alternatively, signals may be transmitted and received wirelessly without passing through an AC line.
[0056]
The determination condition setting unit 62 of the control unit 6 to which the transmission / reception unit 8 is connected is based on the detection value obtained by the temperature sensor 2 and the detection value obtained by detecting the temperature by another fire alarm. Then, at least one of the threshold and the duration is changed.
[0057]
In recent years, highly insulated and airtight houses have become widespread, so that a plurality of rooms in one house have a high correlation with temperature changes. Therefore, the determination is made using the temperature change amount obtained by detecting the temperature with the temperature sensors of the fire alarms installed in the rooms.
[0058]
For example, when the amount of temperature change in a plurality of rooms is within a certain range (for example, within 3 degrees), the temperature rises and the amount of temperature change (temperature difference ΔT ₄ ) Exceeds the set value X, it is determined that the heater (such as the air conditioner) is operating, and the threshold value and the continuation time are not changed. On the other hand, when the amount of temperature change in a plurality of rooms is not within a certain range, the temperature rises and the amount of temperature change (temperature difference ΔT ₄ ) Exceeds the set value X, at least one of the threshold value and the duration is changed.
[0059]
【The invention's effect】
As is clear from the above description, according to the present invention, regardless of the use mode of the room in which the fire alarm is installed (with or without a combustor, with or without an air conditioner, etc.), the occurrence of a fire or the CO concentration or smoke It is possible to provide a fire alarm improved so that an abnormal increase in concentration can be detected at an early stage and false alarms are reduced as much as possible. In particular, even in the case of a smoke-type fire alarm that was not conventionally permitted to be installed in a kitchen, a threshold value and a duration time used for determination of smoke concentration based on a detection value obtained by a temperature sensor that detects a temperature. By changing at least one of the settings, an improved smoke-type fire alarm can be installed in the kitchen.
[Brief description of the drawings]
FIG. 1 is a graph showing (A) temperature change, (B) CO concentration change, and (C) smoke concentration change under a smoldering fire and various conditions.
FIG. 2 is a graph showing (A) a change in temperature, (B) a change in CO concentration, and (C) a change in smoke concentration when a smoldering fire shifts to a full-scale fire.
FIG. 3 is a block diagram showing a configuration of a fire alarm according to one embodiment of the present invention.
FIG. 4 is a flowchart showing the operation of the fire alarm of FIG. 3;
[Explanation of symbols]
1 fire alarm
2 Temperature sensor
3 CO sensor
4 Smoke sensor
5 Changeover switch
6 control unit
7 Alarm section
8 Transceiver
61 AD converter
62 Judgment condition setting section
63 Judgment unit

Claims (17)

A fire alarm for notifying the occurrence of a fire or an abnormal increase in CO concentration or smoke concentration,
An alarm unit for generating an alarm,
A first sensor for detecting temperature;
A second sensor for detecting one of CO and smoke;
The detected value obtained by the second sensor is compared with a set threshold value, and the alarm unit is controlled so as to generate an alarm when a predetermined comparison result continues for a set duration. A determination unit to perform
A determination condition setting unit that changes at least one of the threshold value and the duration based on a detection value obtained by the first sensor;
A fire alarm. A third sensor for detecting the other of CO and smoke;
The determination unit compares the detection value obtained by the third sensor with a set threshold, and generates an alarm when a predetermined comparison result continues for a set duration. Controlling the alarm unit,
The determination condition setting unit changes at least one of the threshold value and the duration based on a detection value obtained by the first sensor,
The fire alarm according to claim 1. The determination unit controls the alarm unit to generate an alarm when a detection value obtained by the second or third sensor exceeds a respective threshold value over a respective duration. Item 3. The fire alarm according to item 1 or 2. The said determination condition setting part sets the said threshold value high, when the variation | change_quantity of the temperature detected by the said 1st sensor exceeds a set value, The threshold value is set high. The described fire alarm. 5. The fire alarm according to claim 4, wherein the determination condition setting unit sets the duration to be short when the amount of change in temperature detected by the first sensor exceeds a set value. 6. The determination condition setting unit may deviate a timing at which the temperature detected by the first sensor rises from a timing at which the detected value obtained by the second or third sensor rises by a predetermined interval or more. The fire alarm according to any one of claims 1 to 3, wherein the setting of the threshold and the duration is not changed in such a case. The determination condition setting unit obtains a temperature change amount based on a detection value selected from among detection values obtained by detecting temperatures at a plurality of time points included in a predetermined period, and calculates the temperature change amount. The fire alarm according to any one of claims 1 to 3, wherein when the amount exceeds a set value, at least one of the threshold and the duration is changed. The fire alarm performs N temperature detections at substantially equal time intervals during the predetermined period,
The determination condition setting unit may determine the average value T _maxj from the higher i-th to the (i + j) th of the detected values obtained by the temperature detection, and the lower i-th to the (i + j) -th. The absolute value ΔT _j = T _maxj −T _minj of the amount of change in the temperature is determined based on the average value T _{minj up to} and the set value is X, ΔT _j > X, and the temperature is increasing. The fire alarm according to claim 7, wherein the threshold is set higher when it is determined that there is a fire alarm. When the predetermined temperature is Y, the determination condition setting unit sets X = X ₁ when T _maxj ≦ Y, and X = X ₂ when T _maxj > Y, where X ₁ > X ₂ 9. The fire alarm according to claim 8, wherein: The judgment condition setting unit is, N times the average value T _P excluding the highest and lowest values of the initial detection value obtained by the M times of the temperature detection of the temperature detection of the last M times of the temperature detection based on the average value T _R excluding the highest and lowest values of the detected values obtained by claim temperature in the case of T _R> T _P, characterized in that the determination that the rising 8 Or the fire alarm according to 9. The apparatus further includes a changeover switch used to change a determination condition depending on whether or not the installation location of the fire alarm is a kitchen,
The determination condition setting unit sets the threshold value higher when the installation location of the fire alarm is set to the kitchen in the changeover switch than when the installation location is not so. 4. The fire alarm according to any one of 3. The said determination condition setting part sets the said continuation time longer than the case where the installation place of the said fire alarm is set to the kitchen by the said change switch, otherwise. The described fire alarm. It further comprises a transmitting and receiving unit for transmitting and receiving signals to and from other fire alarms installed in other rooms,
The determination condition setting unit is configured to determine the threshold value and the continuation time based on a detection value obtained by the first sensor and a detection value obtained by detecting the temperature by the other fire alarm device. The fire alarm according to any one of claims 1 to 3, wherein at least one of the settings is changed. The determination condition setting unit is configured to determine a temperature change amount obtained by the first sensor detecting the temperature and a temperature change amount based on a detection value obtained by the other fire alarm device detecting the temperature. 14. The method according to claim 13, wherein when a correlation within a predetermined range is obtained between the change amount and the change amount, the threshold value and the duration are not changed even when the change amount of the temperature exceeds a set value. Fire alarm. A method for determining the occurrence of a fire or an abnormal increase in CO concentration or smoke concentration in a fire alarm installed indoors,
(A) detecting the temperature using the first sensor and detecting one of CO and smoke using the second sensor;
(B) comparing a detection value obtained by the second sensor with a set threshold value and generating an alarm when a predetermined comparison result continues for a set duration time;
(C) changing at least one of the threshold and the duration based on a detection value obtained by the first sensor;
(D) comparing the detection value obtained by the second sensor with the changed threshold value and generating an alarm when a predetermined comparison result continues for the changed duration time;
A fire determination method comprising: Step (a) includes detecting the other of CO and smoke using a third sensor;
Step (b) compares the detection value obtained by the third sensor with a set threshold value, and generates an alarm when a predetermined comparison result continues for a set duration. Including
Step (c) includes changing at least one of the threshold value and the duration based on a detection value obtained by the first sensor;
Step (d) includes comparing the detection value obtained by the third sensor with the changed threshold value, and generating an alarm when the predetermined comparison result continues for the changed duration time. ,
The method for determining a fire according to claim 15. The step (b) or (d) includes generating an alert if the detected value obtained by the second or third sensor exceeds a respective threshold for a respective duration. 15. The fire determination method according to 15 or 16.

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