JPH0554272A - Fire alarm system - Google Patents

Abstract

PURPOSE:To provide the fire alarm system which finds a fire in its early stage. CONSTITUTION:A receiver 2 is connected to an analog fire sensor 1. The receiver has a processing part 3, a likelihood determination part 4, a dangerousness calculation part 6, a storage time determination part 7, a fire judgement part 9, etc. The likelihood determination part 4 determines fire likelihood and non-fire likelihood according to the features of the time-series data of an analog sense output extracted by the processing part 3. The dangerousness calculation part 6 calculates degree of dangerousness such as the easiness of misalarming occurrence determined from the fire likelihood, non-fire likelihood, the frequency of misalarming occurrence generated after the system installation. In this case, a 1st and a 2nd storage time are set and the storage time determination part 7 determines the storage time according to the degree of dangerousness calculated by the dangerousness calculation part 6. The fire judgement part 9 counts the storage time determined by the storage time determination part 7 and outputs a signal for generating a fire alarm when the level of the analog sense output at the end of the counting is higher than an alarm level.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to fire alarm systems.

[0002]

2. Description of the Related Art Conventionally, an analog photoelectric smoke detector or an analog sensing output from an analog ion smoke detector is returned to a receiver (or a repeater) by using time division multiplex transmission, etc. In the repeater, the returned sensor output counts for a predetermined time (hereinafter referred to as “accumulation time”) from the time when it exceeds a preset level, and the sensor output exceeds a certain level at the end of that accumulation time. There is a fire alarm system that gives an alarm when it is on.

[0003]

By the way, in the conventional system, when the level of the analog detection output of the analog fire detector falls below the alarm level within the accumulation time, the accumulation is simply released at that point and the state returns to the initial state. It is like this. Therefore, when the analog sensing output level exceeds the alarm level again after it has dropped once, the same accumulation time as the first time is set.

However, in such a situation, it is considered that the risk of fire occurrence is increasing, and there is a problem that the timing of issuing an alarm will be delayed if the same storage time as the first time is waited for. The present invention has been made in view of the above problems, and it is an object of the present invention to provide a fire alarm system capable of early detection of a fire at the time of its purpose.

[0005]

In order to achieve the above object, the invention according to claim 1 counts the accumulation time when the level of the analog detection output of the analog fire detector reaches a preset alarm level. In the fire alarm system that determines whether to issue an alarm by the analog detection output at the end of the count, the first accumulation time is set when the level of the analog detection output first exceeds the alarm level. If the level of the analog sensing output falls below the alarm level within the first accumulation time and rises again within a certain period to exceed the alarm level, a second accumulation time shorter than the first accumulation time is set. is there.

The time obtained by subtracting the time from when the level of the analog sensing output first exceeds the alarm level to when it falls below the alarm level from the first accumulation time may be used as the second accumulation time, or the second accumulation time. The storage time may be the minimum storage time.

[0007]

According to the present invention, the analog sensing output level first exceeds the alarm level and counting of the accumulation time is started, and then the analog sensing output level falls below the alarm level within the accumulation time. After that, in a situation in which the alarm level starts to rise again within a certain time and the alarm level is exceeded again, that is, when there is a high-risk situation, the second accumulation time can be shortened to accelerate the detection of fire.

[0008]

EXAMPLES The present invention will be described below with reference to examples. FIG. 1 shows a schematic configuration diagram of the fire alarm system of the present invention.
It is composed of an analog fire detector 1 which is, for example, a photoelectric type or ion type smoke detector installed in a warning place, and a receiver 2 which receives analog detection output data of the analog fire detector 1. A well-known time division multiplex transmission or the like is used between the receiver 2 and the analog fire detector 1 to output analog detection output data from the analog fire detector 1 to the receiver 2
The receiver 2 is adapted to receive the analog sensing output by an appropriate method such as sending it back to.

The receiver 2 receives the data of the analog sensing output in time series, processes the time series data, and extracts the characteristic amount of the time series data. After the system is installed, the certainty factors determined by the certainty factor determination unit 4 that determines the certainty factor of fire and the certainty factor of non-fire based on the fired data and the non-fire determination rule described below, and the certainty factor determined by the certainty factor determination unit 4 The risk calculation unit 6 calculates the risk and the like based on the likelihood of false alarms determined from the frequency of occurrence of false prediction, and the accumulation time is calculated according to the risk calculated by the risk calculator 6. The pre-alarm level used for determining the accumulation time determining unit 7 and the certainty factor according to the above-mentioned fire determination rule and for starting counting of the accumulation time, and the alarm level are detected by the presence / absence sensor 10, the air conditioning equipment operation detection unit 11, etc. Set according to the detection status Level determination unit 8 and the accumulation time determined by the accumulation time determination unit 7 and outputs a signal for generating a fire alarm if the analog detection output level at the end of counting is equal to or higher than the alarm level. Part 9 and the above-mentioned false-prediction occurrence frequency, which is initially set based on the installation location of the analog fire detector 1, updates the false-prediction occurrence frequency for each time zone based on the collection of the false-prediction occurrence data after the installation. A fire notification unit for giving a fire notification based on a signal from a false prediction frequency update storage unit 5 that gives updated risk data to the risk calculation unit 6 as data on the likelihood of false alarms, and a signal from the fire determination unit 9. 12, and a microcomputer is actually used.

Next, the degree of risk used in the system of the present invention,
The judgment rules and the like will be described. First, the risk level is a scale that takes a value from 0 to 100 with 100 when the fire alarm is generated, and this risk level fluctuates through three stages. First, as shown in FIG. 2, the level of the analog sensing output to the alarm level L ₀ , that is, the stage until the sensed smoke density is reached is defined as the first stage, and in this first stage, false alarms are likely to occur (the analog fire detector 1 Depending on the installation situation, environment, time zone, season, frequency of past false forecasts), the risk is increased in proportion to the value of the detected smoke density according to the slope determined.

[0011] the warning level L ₀ to the sensing smoke stage concentration reaches the second stage, in the second Sureji, by the time series data sensed smoke density to reach a warning level L _0, a preselected decision rule Based on this judgment, it is judged whether it is a non-fire or not, and the risk is raised or lowered based on this judgment. Next, after the detected smoke density exceeds the alarm level L ₀ , the third stage is set. In this third stage, the accumulation time is set by the degree of danger determined by the second stage, and the counting of the accumulation time is completed. At this point, if the detected smoke density remains above the alarm level L ₀ , a warning is given with a danger level of 100.

Under the above conditions, the risk is calculated by the risk calculator 6. The determination rule is for determining the degree of risk in the second stage, and this determination rule is defined as follows. The rule for determining the certainty factor that water vapor is based on the time-series data of the detected smoke concentration is as follows.

First, there is a feature that the concentration of sensed smoke corresponding to water vapor sharply rises from 0%. Therefore, the pre-alarm level L set at about half the alarm level L ₀
Time T until the sensing smoke density to ₁ reaches from beyond the 1%
p is short as shown in FIG. 3, this time range is set to a range from 0 seconds to 9 seconds as shown in FIG. 4, 0 seconds is a confidence factor of 0, and 9 seconds or more is a confidence factor of 1, The first certainty factor X ₁ is determined according to the actual measurement time. And pre-alarm level L ₁
The time Tpa for reaching the alarm level L ₀ is also short, and this time range is set to a range from 0 seconds to 9 seconds as shown in FIG. 5, with 0 second being the confidence factor 0 and 9 seconds or more being the confidence factor. Then, the second certainty factor X ₂ is determined according to the actual measurement time. And the average value (X ₁ + X ₂ ) / of these two confidences X ₁ and X ₂
2 is defined as the water vapor certainty factor X.

Similarly, the rules for determining the certainty factor that the smoke is a smoke based on the time-series data of the sensed smoke density are as follows. As for the perceived smoke density corresponding to cigarette smoke, before the smoke density suddenly rises, as shown in FIG.
There is a feature that the state of 2% continues. Therefore, when the detected smoke density is sampled a certain number of times (20 times) in the past minute, the ratio a / 20 of the number a of data in the range of 0.5 to 2.5% is set as the first certainty factor Y ₁ , Concentration is about 2.5%
The time Ta required to reach the alarm level L ₀ is exceeded in FIG.
As shown in, the certainty factor is set to 0, and the certainty factor is set to 0 when the maximum permissible time of 9 seconds which is determined to be cigarette smoke is exceeded,
The second confidence factor Y ₂ is obtained from the actual measurement time until the detected smoke concentration exceeds approximately 2.5% and reaches the alarm level L _0, and the average value of these first and second confidence factors Y ₁ and Y ₂ ( Y ₁ + Y ₂ ) /
From 2, the cigarette confidence factor Y due to the cigarette smoke is determined.

The above-described water vapor certainty factor X and cigarette certainty factor Y are used as the non-fire certainty factor for determining the risk in the second stage. In this case, the decision rule to be adopted is selected depending on the place of installation, that is, a place where water vapor is likely to be generated, such as a kitchen, or a place where cigarettes are often smoked. The rules for determining the certainty factor of a fire are as follows. That is, the range up to a predetermined time (for example, 3 minutes before) before the time point of exceeding the pre-alarm level L ₁ shown in FIG. 8 is divided into two, and the detected smoke in the previous time range (3 minutes before to 1.5 minutes before). As shown in FIG. 9, the difference between the average density M ₁ and the average smoke density M _{2 in} the subsequent time range (from 1.5 minutes before to the arrival time) is large as shown in FIG. First confidence determined from the average value actually measured under this condition, with a certainty factor of 1 above the maximum value (3%) that can be judged as a fire, and a certainty factor of less than the minimum value (1.5%). Degree Z ₁
Then, as shown in FIG. 10, if the average value M from when the detected smoke density reaches 0% to the pre-alarm level L ₁ is equal to or higher than the maximum value (3%) that can be judged as a fire, the certainty factor is set to 1 and the minimum value ( 1.
(5%) or less, the certainty factor is set to 0, and the minimum value of the second certainty factor Z ₂ determined from the average value actually measured under this condition is determined as the fire certainty factor Z.

The erroneous forecast frequency update storage unit 5 updates the erroneous forecast frequency as follows. First, the determination of the occurrence of a false forecast is made, for example, by the occurrence of an analog sensing output exceeding the pre-warning level, and the false forecast frequency update storage unit 5 divides 24 hours a day into time zones of a certain time width as shown in FIG. Then, the number of false forecast occurrences is aggregated for each time zone, and the false forecast frequency for each time zone is updated once a month based on the data of the past three months, for example.

The risk calculating unit 6 is a false prediction frequency update storage unit 1.
As shown in FIG. 12, the degree of danger when the warning level L ₀ is reached is 40 to 8 based on the time zone false prediction frequency data of _0.
The slope of the increase in the degree of danger according to the detected smoke density in the stage 1 is determined so as to be 0. Next, the operation of the fire alarm system of the present invention will be described with reference to FIGS.

Now, the fire alarm system is activated, and the initial value of the frequency of occurrence of misprediction for each time zone is set in correspondence with the installation location of each analog fire detector 1,
Select and set the fire judgment rule to be applied according to the installation location. Now, when the alarm state is entered, the alarm level L ₀ and the pre-alarm level L ₁ are set to standard values by the level setting unit 8 when the air conditioning equipment is not in operation and a person is present.
Set slightly higher than the standard value when no person is present. Further, when the air conditioner is in operation and a person is present, it is set higher than the standard, and when the person is not present, it is set twice as high as when the person is present.

Now, when the smoke density detected by the analog fire detector 1 starts to rise, the danger level calculation section 6 determines the danger level for smoke density determined based on the false prediction frequency from the false prediction frequency update storage section 5. Calculate the risk based on the slope of the degree. When the detected smoke density reaches the warning level L ₀ , the second stage is entered, and at this time, the risk level calculation unit 6 determines whether or not to change the risk level based on the determination content of the confidence level determination unit 4.

The certainty factor determining unit 4 calculates the non-fire and fire certainty factors based on the time-series data of the detected smoke density in the first stage according to the selected determination rule. When the fire certainty factor determined by the certainty factor determining unit 4 is equal to or higher than a certain value, the risk degree calculating unit 6 increases the risk factor in the range of 80 to 90 according to the fire certainty factor. For example, if the fire certainty factor is 1, the risk factor is increased to 90.

When the fire certainty factor is less than a certain value, the risk factor is increased to a maximum of 80 according to the non-fire certainty factor (cigarette certainty factor, water vapor certainty factor). For example, the non-fire certainty factor is 1
In the case of, the risk level remains unchanged, and when the non-fire certainty factor is 0, the risk level is set to 80. In this way, the risk degree calculation unit 6 calculates the change amount of the risk degree based on the determination content of the certainty factor determination unit 4 in the second stage.

When the detected smoke density exceeds the alarm level L ₀ , the third stage is entered, and the accumulation time determination unit 7 determines the accumulation time based on the degree of danger in the second stage. In other words, if the risk level is 90, which is the highest in the second stage, the accumulation time is 10 seconds, if the risk level is 80, it is 20 seconds, if the risk level is about 60, it is 40 seconds, and if the minimum risk level is 40, 60
As the degree of danger increases, such as seconds, the accumulation time is shortened to accelerate the detection of fire, and conversely, if the degree of risk is low, the time is increased to prevent the occurrence of non-fire alarms.

When the accumulation time is determined, the fire judging section 9 counts the accumulation time, and the smoke density detected by the analog fire detector 1 at the end of the counting is the alarm level L.
If it exceeds ₀ , it is determined that the degree of danger has reached 100, and a signal is sent to the fire reporting unit 12 to cause a fire report. At the same time when the fire is judged, the level setting unit 8 is instructed to change the alarm level L ₀ .

[0024] Also consider the transition of sensing smoke density after determining the cumulative time, after falling sensed smoke density than the warning level L ₀ once the warning level L ₀ within a certain period of time (for example, within 3 minutes) again If it exceeds, there is a high possibility of fire, and the risk calculation unit 6 increases the risk at that point. Due to this rise, the accumulation time determination unit 7 shortens the accumulation time shorter than the initial accumulation time. Therefore, the fire can be found sooner.

If the degree of danger is set to a value such that the second accumulation time is a minimum time that can be set by the system, for example, 5 seconds, a fire alarm can be generated very quickly. Also, for example, the risk is set such that the time from the start of counting the first accumulation time to the time when the detected smoke concentration falls below the alarm level L ₀ is the second accumulation time, which is the time obtained by subtracting the time from the first accumulation time. You may.

[0026] Note that once sensed smoke density is lowered than the warning level L _0, if there be even after 3 minutes exceeds an alarm level L _0, the risk calculation in stage 2 of the next normal as Done. FIG. 13 shows a flow of operations of the above-mentioned respective parts of the alarm system of the present invention. Square boxes indicate input / output variables, and oval boxes indicate inference control parts.

[0027]

According to the present invention, when the level of the analog detection output of the analog type fire detector reaches a preset alarm level, the accumulation time is counted and an alarm is issued by the analog detection output at the end of the counting. In the fire alarm system that determines whether or not the level of the analog sensing output exceeds the warning level for the first time, the first accumulation time is set, and the level of the analog sensing output exceeds the warning level within the first accumulation time. If it falls, rises again within a certain period and exceeds the alarm level, the second time shorter than the first accumulation time is reached.
Since the analog sensing output level first exceeds the alarm level and counting of the accumulation time is started, the analog sensing output level drops below the alarm level within the accumulation time, and then within a fixed time. Even if a situation where the alarm level starts rising again and the alarm level is exceeded again, that is, a high-risk situation occurs, shorten the second accumulation time,
This has the effect of speeding fire detection and building a highly reliable system.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is an operation explanatory view showing the determination transition of the degree of danger and the accumulation time according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram of a water vapor determination rule according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a water vapor determination rule according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram of a water vapor determination rule according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram of a cigarette smoke determination rule according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram of a cigarette smoke determination rule according to an embodiment of the present invention.

FIG. 8 is an explanatory diagram of a fire determination rule according to an embodiment of the present invention.

FIG. 9 is an explanatory diagram of a fire determination rule according to the embodiment of this invention.

FIG. 10 is an explanatory diagram of a fire determination rule according to an embodiment of the present invention.

FIG. 11 is an explanatory diagram of counting false alarm frequency according to an embodiment of the present invention.

FIG. 12 is an explanatory diagram of the smoke density and the slope of the danger level of the stage 1 according to the embodiment of the present invention.

FIG. 13 is a flowchart for explaining the overall operation of the embodiment of the present invention.

[Explanation of symbols]

 1 Analog fire detector 2 Receiver 3 Processing unit 4 Confidence determination unit 6 Risk calculation unit 7 Accumulation time determination unit 9 Fire determination unit

Claims (3)

[Claims] 1. When the level of the analog detection output of the analog fire detector reaches a preset alarm level, the accumulation time is counted and it is determined whether or not an alarm is issued by the analog detection output at the end of the counting. In the fire alarm system, the first accumulation time is set when the level of the analog detection output exceeds the alarm level for the first time, and the level of the analog detection output falls below the alarm level within the first accumulation time for a certain period. A fire alarm system characterized by setting a second accumulation time shorter than the first accumulation time when the temperature rises again and exceeds the alarm level. 2. The second accumulation time is defined as the time obtained by subtracting the time from when the level of the analog sensing output first exceeds the alarm level to when it falls below the alarm level from the first accumulation time. The fire alarm system according to claim 1. 3. The fire alarm system according to claim 1, wherein the second accumulation time is a minimum accumulation time.