CN106935005B - Test device and method for evaluating dust transient interference resistance of smoke detector - Google Patents

Abstract

The invention provides a test device for evaluating the anti-dust transient interference performance of a smoke detector, which is composed of a test box, a dust generating device and a test parameter monitoring device. Two detectors can be fixed on a fixed plate in the test box. The side wall of the box is provided with a dust filling port to connect with the dust generating device, and the test parameter monitoring device includes an optical smoke density meter, a temperature and humidity meter and an anemometer. The invention also provides a test method for evaluating the anti-dust transient interference performance of the above-mentioned test device: setting test conditions; placing two detector samples in a test box to make them in a normal monitoring state and run stably for 15 minutes; Introduce dust at a certain rate to test the response of the smoke detector, and determine the anti-dust ability of the detector according to the parameter standards of different anti-dust interference ability levels, which provides a basis for the research and application of the detector.

Description

Test device and method for evaluating the anti-dust transient interference performance of smoke detectors

Technical field:

The invention relates to performance detection of smoke detectors, in particular to a test device and a test method for evaluating the anti-dust transient interference performance of smoke detectors.

Background technique:

Because smoke detectors mostly use the principle of light scattering, under the action of airflow, dust entering the detection cavity of the detector will generate light scattering signals, which will cause the analog value of the detector to rise in a short time and generate false alarms. Dust suspended in the air is the main cause of false alarms of smoke detectors. An assessment by the International Association for Fire Safety Sciences (IAFSS), the National Institute of Standards and Technology (NIST), and the Society of Fire and Fire Engineers (SFPE) found that the reliability of smoke detection systems in homes, commercial buildings, and public institutions Between 67% and 86%, there is a lot of room for improvement.

Different brands of detectors have different resistance to short-term transient interference from dust due to their different identification algorithms and detection cavity structures. In practical engineering applications, the dust concentration in different places is quite different. For example, the content of particulate matter in the air of ordinary residential buildings is relatively low, and the content of particulate matter in semi-enclosed venues, tunnels and other places is relatively high. Places with more severe interference may have higher dust concentrations. Therefore, smoke detectors should be used in specific environmental places according to their ability to resist dust transient interference. But at present, there is still a lack of test devices and methods that can quantitatively evaluate the anti-dust transient interference performance of smoke detectors at home and abroad.

GB/T2423.37-2006/IEC60068-2-68:1994 "Environmental Test of Electrical and Electronic Products" stipulates different "sand and dust test" methods for electrical and electronic products, mainly to evaluate the general impact of sand and dust on electrical and electronic products, Examples include sand and dust causing contact failures, seizure of kinematic bearings, surface wear, and blockage of vents or filters. These test methods are not suitable for testing the false alarm or working point drift of fire detectors due to dust interference, so these test methods have not been used to test fire detectors in the field of fire detection and alarm. In addition, the dust test chamber specified in GB/T2423.37-2006/IEC60068-2-68:1994 "Environmental Testing of Electrical and Electronic Products" cannot control the stability of dust concentration, so it cannot be used for quantitative smoke detector dust Contamination test.

The American UL standard UL268-2006 "Smoke detectors for fire alarm signaling system" (smoke detectors) and UL217-2015 "Standard for safety smoke alarms" (smoke alarm safety standard) stipulates the fire detector dust test method, The purpose of this method is to test whether the fire detector can still work normally after a large concentration of dust pollution. However, in this experiment, the test device could not realize the quantitative control of the internal dust concentration, and could not carry out the quantitative evaluation of the anti-dust transient interference performance of the smoke detector.

Invention content:

In view of the problems existing in the prior art, the purpose of the present invention is to provide a test device and a test method for evaluating the anti-dust transient interference performance of the smoke detector, so as to correctly evaluate the anti-dust transient interference performance of the smoke detector. Provide scientific evidence.

In order to achieve the above purpose, the test device for evaluating the anti-dust transient interference performance of the smoke detector provided by the present invention includes a test box, a dust generating device and a test parameter monitoring device, and the inner top wall of the test box is provided with a detector. The detector fixing plate, the test parameter monitoring device includes an anemometer, a temperature and humidity meter, and an optical smoke densitometer arranged on the detector fixing plate. Two detector bases are arranged symmetrically about its axis; the test box includes an upper dust mixing area and a lower dust settling area, the side wall of the test box corresponding to the upper dust mixing area is provided with a dust filling port, and the lower part is provided with a dust filling port. There is a heater in the dust settlement area, a circulating pump is connected to the bottom of the test box, and the circulating pump is respectively connected with a dust conveying channel and a dust discharge channel, and the dust blowing port of the dust conveying channel is located in the upper part of the dust mixing In the area, the dust discharge channel is connected with the dust discharge port of the test box, and an electric valve is provided on it; the dust generating device includes an air compressor, a dust generator connected with the air compressor, and the dust The generator is connected to the dust supply port through a pipeline.

The test box also includes a control cabinet, which controls the activation and closing of the circulation pump, the heater, the oscillator and the electric valve, and the anemometer and the temperature and humidity The control panel of the control cabinet is linked through a serial port.

The dust generator is provided with a knob for controlling the dust feeding rate, and the dust feeding rate of the dust generator ranges from 0.3 to 50 mg/s.

The vertical distance from the dust blowing port to the side wall of the test box where the dust replenishing port is located is equal to the vertical distance from the dust blowing port to the top wall of the test box.

The straight line where the two detector bases are located is perpendicular to the airflow direction of the dust blowing port.

The measurement range of the dust optical concentration m value of the optical smoke densitometer is at least 0-2 dB/m, and the measurement accuracy is 0.01 dB/m.

The dust concentration range in the test box is (1 mg/m ³ -500 mg/m ³ )±10%.

The present invention also provides a test method for evaluating the anti-dust transient interference performance using the above-mentioned test device for evaluating the anti-dust transient interference performance of the smoke detector, comprising the following steps:

Step 1. Set the test conditions: the initial dust concentration in the test box is lower than 0.01dB/m; the temperature is 23±5℃; the relative humidity is less than 25%; the airflow velocity around the smoke detector is 0.5±0.1m/ s;

Step 2. Select two smoke detectors of the same type. For the smoke detector with variable response threshold, the setting of the response threshold is the same, and then installed on the detector fixing plate in the test box to make it in the same position. Normal monitoring state and stable operation for 15min;

Step 3. Start the heater and the circulating pump to make the temperature, relative humidity and airflow around the smoke detector meet the test conditions; The growth of the m value of the dust optical concentration in the test box collected by the smoke densitometer is within a certain range, and the state of the smoke detector is observed at the same time. Specifically, the test is divided into four levels according to the different dust concentrations, which are simulated environment. Level I for places with more serious interference: the environmental parameter dust optical concentration m value is 0.5dB/m, the light reduction rate is 10.9%/m, and the second level simulates general places: the environmental parameter dust optical concentration m value is 0.088dB/m, light reduction rate of 2%/m, class III simulated clean place: its environmental parameter dust optical density m value is 0.035dB/m, light reduction rate of 0.8%/m, and simulated dust-free place Class IV: the environmental parameter dust optical concentration m value is less than 0.035dB/m, and the light reduction rate is less than 0.8%/m; when two smoke detectors are tested for Class I and II, the dust The speed of the test chamber should meet the requirements of 0.19dBm ^-1 min ^-1 ≤△m/△t≤0.418dBm ^-1 min ^-1 , the growth range of the m value of the dust optical concentration in the test box is 0～1dB/m, when m=1dB/ The test ends when m or one of the smoke detectors sends an alarm signal. When the two smoke detectors are tested for the third and fourth grades, the rate of dust penetration should meet the requirements of 0.015dBm ^-1 min ^-1 ≤△m /△t≤0.1dBm ^-1 min ^-1 , the growth range of the m value of the dust optical concentration in the test chamber is 0～0.088dB/m, when m=0.088dB/m or one of the smoke detectors sends out an alarm signal when the test ends;

Step 4. Judging according to the test results: when the dust concentration in the test box reaches the dust concentration corresponding to the m value of the dust optical concentration under each test level, the two smoke detectors do not alarm, indicating that the type of smoke detector passes the test. Level test, the highest level passed by this type of smoke detector is regarded as its anti-dust transient interference level.

As can be seen from the above technical solutions, the beneficial effects of the present invention:

The test device and the test method of the present invention can precisely control the dust concentration to increase at a certain rate at a relatively small concentration, simulate the change of space dust similar to fire smoke, test the response of the smoke detector, and evaluate the smoke detector's performance. The ability to resist dust transient interference provides a basis for determining the suitable environment for smoke detectors.

Description of drawings:

1 is a schematic structural diagram of a test device for evaluating the anti-dust transient interference performance of a smoke detector according to an embodiment of the present invention;

Fig. 2 is the structural representation of the detector fixing plate in Fig. 1;

In this embodiment: 1- test box, 2- detector fixing plate, 3- optical smoke density meter, 4- temperature and humidity meter, 5- anemometer, 6- dust blowing port, 7- dust filling port, 8- Dust generator, 9-air compressor, 10-circulation pump, 11-heater, 12-electric valve, 13-dust outlet, 14-control cabinet, 15-detector base, 16-control and display equipment connection , 17- Airflow direction, 18- Dust conveying channel, 19- Dust discharge channel.

Detailed ways:

The present invention will be described in further detail below with reference to the accompanying drawings and embodiments. The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

As shown in Figure 1, the present invention provides a test device for evaluating the anti-dust transient interference performance of a smoke detector, including a test box 1, a dust generating device and a test parameter monitoring device. The test box 1 includes upper and lower parts, the upper part is a cube shape of 1000mm×1000mm×1000mm, the inner space is the upper dust mixing area, and the lower part is a regular quadrangular pyramid shape with a bottom side length of 1000mm and a height of 1000mm, Its inner space is the lower dust deposition area. The left side wall of the test box 1 corresponding to the upper dust mixing area is provided with a dust filling port 7, and the vertical distance between the dust filling port 7 and the bottom surface of the upper dust mixing area is 100 mm. The front side of the test box is a door that can be opened manually.

There is a heater 11 in the lower dust settlement area, which can heat the interior of the test box 1 up to 50°C, and play a role in drying, so that the temperature and humidity in the test box 1 are within a certain range; The bottom of the test box 1 is connected with a circulating pump 10, and the circulating pump 10 is respectively connected with a dust conveying channel 18 and a dust discharging channel 19, and the dust blowing port 6 of the dust conveying channel 18 is located in the upper dust mixing area, The dust discharge channel 19 is connected to the dust discharge port 13 of the test box 1, and an electric valve 12 is arranged thereon; the sample box 1 further includes a control cabinet 14, and the control cabinet 14 controls the circulation Start and stop of the pump 10 , the heater 11 and the electric valve 12 .

The dust generating device includes an air compressor 9 and a dust generator 8 , and the dust generated by the dust generator 8 enters the test box 1 through the dust supply port 7 . The dust generator 8 is connected with the computer through a serial port, and the startup and shutdown of the dust generator 8 can be controlled by the program in the computer, and the dust adding rate of the dust generator can be controlled. The dust adding rate of the dust generator ranges from: 0.3～50mg/s.

The test parameter monitoring device includes an optical smoke density meter 3, an anemometer 5, and a temperature and humidity meter 4. The inner side of the top wall of the test box 1 is provided with a detector fixing plate 2 with a diameter of 240 mm, as shown in Figure 2, The anemometer 5 and the temperature and humidity meter 4 are both installed on the detector fixing plate 2, and the optical smoke density meter 3 is fixed in the test box 1 and located in the upper dust mixing area. On the detector fixing plate 2, two detector bases 15 are symmetrically arranged front and rear about its axis for fixing the smoke detector. The dust blowing port 6 is to the left of the test box 1 where the dust filling port 7 is located. The vertical distance of the side wall is equal to the vertical distance from the dust blowing port 6 to the top wall of the test box 1, which is 200mm; and the straight line where the two detector bases 15 are located is perpendicular to the airflow of the dust blowing port 6 Therefore, the airflow received by the two smoke detectors is uniform, and the dust concentration is basically the same. The anemometer 5 and the temperature and humidity meter 4 are linked with the control panel of the control cabinet 14 through a serial port, so the temperature, humidity and wind speed in the test box 1 can be displayed on the control panel in real time; The densitometer 3 is connected to the computer through a serial port, and is used to collect the dust optical density data near the detector fixed plate 2 in the test box 1, and display it in real time through the computer. The dust optical density m of the optical smoke density meter 3 is displayed. The measurement range of the value is at least 0~2dB/m, and the accuracy is 0.01dB/m. The computer adjusts the dust adding rate of the dust generator 8 according to the data fed back by the optical smoke density meter 3, and then adjusts and controls the test box 1. dust concentration.

During the test, the compressed air generated by the air compressor 9 flows through the dust generator 8, and the dust enters the test box 1 through the dust filling port 7, and the circulating pump 10 can control the test box 1 A stable circulating air flow is formed inside, with reference to FIG. 1 , part of the dust settled in the lower dust settlement area can be blown out from the dust blowing port 6 again, so that the dust forms a circulation path, and further, on the dust generator 8 There is a knob for controlling the dusting rate. Adjusting the knob can make a small amount of dust during the dust cycle. This closed-loop control can realize the dust concentration in the test box 1 (1mg/m ³ -500mg/m ^{3 )} . ) ±10% controllable. The power of the circulating pump 10 can be adjusted, and its power range should make the airflow velocity near the detector fixed plate 2 adjustable within the range of 0 to 2 m/s, and the adjustable accuracy should reach 0.05 m/s. The standard atmospheric pressure is always maintained in the test box 1 .

When the above-mentioned test device is used to evaluate the anti-dust transient interference performance of the smoke detector, in order to make the smoke detector apply to a specific environment according to its anti-dust transient interference ability, it is now given as shown in Table 1. The level standard of anti-dust transient interference ability of smoke detectors, according to Table 1, to judge the anti-dust interference ability of smoke detectors and the places suitable for use.

Table 1 Point-type smoke detection ability classification against dust transient interference

The key parameters involved in Table 1 are set based on:

The dust optical concentration m value and light reduction rate data of the same level can be converted to each other and correspond one by one.

The m value of 0.5dB/m refers to the first-level sensitivity requirements of the sensitivity division in the national standard GB4715-1993 "Technical requirements and test methods for point-type smoke and fire detectors" which have been cancelled. The dust concentration of the transient interference that the detectors used in general places are set at the highest sensitivity (the worst anti-dust transient interference ability) is the classification basis for general places and places with more serious environmental interference, that is, the dust concentration reaches When this parameter is used, the detector does not alarm, and the detector has the strongest anti-dust interference ability and meets the requirements of Class I. The detector can be used in places with severe environmental interference.

The dimming rate of 2%/m is a sensitive and common classification parameter in the aspirating response threshold classification method in the national standard GB15631-2008 "Special Fire Detectors", and the detector type with a response threshold greater than 2%/m is common. That is, during the transient interference test, if the detector does not alarm when the dust concentration reaches this parameter, the detector has a certain anti-dust interference ability, meets the requirements of Class II, and can be used in general places.

Sensitive and highly sensitive classification parameters in the aspirating response threshold classification method in the national standard GB15631-2008 "Special Fire Detectors": the response threshold is greater than 0.8%/m and less than or equal to 2%/m is sensitive, then the transient interference test When the dust concentration reaches 0.8%/m, the detector does not alarm, the detector has poor anti-dust interference ability, meets the requirements of class III, and can be used in clean places; the response threshold is less than 0.8%/m, which is highly sensitive, and the detector is in During the transient interference test, the alarm will be issued before the dust concentration reaches 0.8%/m. The detector does not have the ability to resist dust interference, which meets the requirements of Class IV and is suitable for use in dust-free places.

Example 1:

A certain type of smoke detector will be installed in the tunnel, and this type of detector needs to be tested for transient disturbance of Class I and II dust. Using the above-mentioned test device for evaluating the anti-dust transient interference performance of the smoke detector, according to the test method of the present invention, the anti-dust interference ability of this type of smoke detector is tested and evaluated:

(1) Set the test conditions: the initial dust concentration in the test box is less than 0.01dB/m; the temperature is 23±5℃; the relative humidity is less than 25%; the airflow velocity around the smoke detector is 0.5±0.1m/m s;

(2) Select 2 smoke detectors of this type, whose response thresholds are set the same; install the 2 smoke detectors of this type on the detector fixing plate in the test box, and connect to the fire alarm through the bus Controller, make it in normal monitoring state and run stably for 15min;

(3) Start the heater and circulating pump to make the temperature, relative humidity and airflow around the smoke detector meet the requirements of the test conditions; start the air compressor and dust generator, and the rate of entering dust meets the requirements of 0.19dBm ^-1 min ^-1 ≤△m/△t≤0.418dBm ^-1 min ^-1 (refer to the national standard GB4715-2005 "Point Type Smoke Detector" Appendix H Test Fire SH2-Cotton Rope Smoldering Fire Diagram H.3), When the m value reaches 0.5dB/m, the two smoke detectors of this type do not send out a fire alarm signal;

(4) Judgment conclusion: This type of detector meets the requirements of Class I, has strong anti-dust interference ability, and is suitable for use in places with severe environmental interference (including tunnel sites).

Example 2:

A certain type of smoke detector will be installed in the evacuation corridor, elevator front room and room of a hotel. This type of detector needs to be tested for transient interference of grades I and II. Using the above-mentioned test device for evaluating the anti-dust transient interference performance of the smoke detector, according to the test method of the present invention, the anti-dust interference ability of this type of smoke detector is tested and evaluated:

(1) Set the test conditions: the initial dust concentration in the test box is less than 0.01dB/m; the temperature is 23±5℃; the relative humidity is less than 25%; the airflow velocity around the smoke detector is 0.5±0.1m/m s;

(2) Select 2 smoke detectors of this type, whose response thresholds are set the same; install the 2 smoke detectors of this type on the detector fixing plate in the test box, and connect to the fire alarm through the bus Controller, make it in normal monitoring state and run stably for 15min;

(3) Start the heater and the circulating pump to make the temperature, relative humidity and airflow around the smoke detector meet the requirements of the test conditions; start the air compressor and dust generator, and the rate of entering dust meets 0.19dBm ^-1 min ^-1 ≤△m/△t≤0.418dBm ^-1 min ^-1 (refer to the national standard GB4715-2005 "Point Type Smoke Detector" Appendix H Test Fire SH2-Cotton Rope Smoldering Fire Diagram H.3), When the m value reaches 0.088dB/m, one of the smoke detectors of this type sends out a fire alarm signal, and the other smoke detector of this type does not send out a fire alarm signal;

(4) Judgment conclusion: This type of detector does not meet the requirements of Class II, and has poor dust resistance, so it is not suitable for use in general places (including hotel evacuation corridors, elevator front rooms, rooms, etc.).

Example 3:

A certain type of aspirating smoke detector will be installed in a large computer room, and this type of detector needs to be tested for transient interference of grades III and IV of dust. Using the above-mentioned test device for evaluating the anti-dust transient interference performance of the smoke detector, according to the test method of the present invention, the anti-dust interference ability of this type of smoke detector is tested and evaluated:

(1) Set the test conditions: the initial dust concentration in the test box is less than 0.01dB/m; the temperature is 23±5℃; the relative humidity is less than 25%; the airflow velocity around the smoke detector is 0.5±0.1m/m s;

(2) Select 2 smoke detectors of this type, whose response thresholds are set the same; install the 2 smoke detectors of this type on the detector fixing plate in the test box, and connect to the fire alarm through the bus Controller, make it in normal monitoring state and run stably for 15min;

(3) Start the heater and the circulating pump to make the temperature, relative humidity and airflow rate around the smoke detector meet the test conditions; start the air compressor and dust generator, and the rate of dust inflow satisfies: 0.015dBm ^{- 1} min ^-1 ≤△m/△t≤0.1dBm ^-1 min ^-1 (refer to the national standard GB4715-2005 "Point Type Smoke Detector" Section 4.1.5 Response Threshold Measurement), when the m value reaches 0.035dB /m, the two smoke detectors of this type have not issued a fire alarm signal;

(4) Judgment conclusion: This type of detector meets the requirements of Class III and can be installed in clean places (including large computer rooms).

The smoke detectors selected by default in the above three embodiments will not fail, because the method of the present invention is to evaluate the anti-dust interference ability of the smoke detectors, and the smoke detectors need to be tested under normal operation. evaluation.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope defined by the claims of the present invention .

Claims (7)

1. The utility model provides a test device of evaluating smoke detector anti dust transient state interference performance which characterized in that includes: the device comprises a test box body, a dust generating device and a test parameter monitoring device, wherein a detector fixing disc is arranged on the inner side of the top wall of the test box body, the test parameter monitoring device comprises an anemometer, a hygrothermograph and an optical smoke densitometer, the anemometer and the hygrothermograph are arranged on the detector fixing disc, and two detector bases are symmetrically arranged on the detector fixing disc around the axis of the detector fixing disc; the test box body comprises an upper dust mixing area and a lower dust settling area, the side wall of the test box body corresponding to the upper dust mixing area is provided with a dust supplementing port, the lower dust settling area is internally provided with a heater, the bottom of the test box body is connected with a circulating pump, the circulating pump is respectively connected with a dust conveying channel and a dust discharging channel, a dust blowing port of the dust conveying channel is positioned in the upper dust mixing area, the dust discharging channel is connected with a dust discharging port of the test box body, and an electric valve is arranged on the dust discharging channel; the dust generating device comprises an air compressor and a dust generator connected with the air compressor, and the dust generator is connected with the dust supplementing port through a pipeline; and the vertical distance from the dust blowing port to the side wall of the test box body where the dust supplementing port is positioned is equal to the vertical distance from the dust blowing port to the top wall of the test box body.

2. The test apparatus for evaluating the dust transient interference resistance of a smoke detector as claimed in claim 1, wherein: the test box body further comprises a control cabinet, the control cabinet controls the circulating pump, the heater, the oscillator and the electric valve to be started and closed, and the anemometer and the hygrothermograph are connected with a control panel of the control cabinet through serial ports.

3. The test apparatus for evaluating the dust transient interference resistance of a smoke detector as claimed in claim 1, wherein: the dust generator is provided with a knob for controlling the dust adding speed, and the dust adding speed range of the dust generator is 0.3-50 mg/s.

4. The test apparatus for evaluating the dust transient interference resistance of a smoke detector as claimed in claim 1, wherein: the straight line where the two detector bases are located is perpendicular to the airflow direction of the dust blowing port.

5. The test apparatus for evaluating the dust transient interference resistance of a smoke detector as claimed in claim 1, wherein: the measurement range of the dust optical concentration m value of the optical smoke density meter is at least 0-2dB/m, and the measurement precision is 0.01 dB/m.

6. The test apparatus for evaluating the dust transient interference resistance of a smoke detector as claimed in claim 1, wherein: the dust concentration range in the test box body is (1 mg/m) ³-500mg/m³)±10％。

7. The test method for evaluating the dust transient interference resistance of the smoke detector according to claim 1 is characterized by comprising the following steps:

step 1, setting test conditions: the initial dust concentration in the test box body is lower than 0.01 dB/m; the temperature is 23 +/-5 ℃; the relative humidity is less than 25%; the flow velocity of the airflow around the smoke detector is 0.5 +/-0.1 m/s;

step 2, selecting two smoke detectors of the same type, wherein the smoke detectors with variable response thresholds are selected, the response thresholds are set identically, and then the smoke detectors are installed on a detector fixing disc in a test box body and are in a normal monitoring state and stably run for 15 min;

step 3, starting the heater and the circulating pump to enable the temperature and the relative humidity in the test chamber and the flow velocity of the airflow around the smoke detector to reach a testTesting the condition requirement; start air compressor and dust generator, let in the dust with certain speed, the increase of the dust optical concentration m value in the proof box that makes the optics smoke density meter gather is in the certain limit, observes smoke detector's state simultaneously, and is concrete, divide into four grades to the experiment according to the difference of dust concentration, is the I level in the more serious place of simulation environmental disturbance respectively: the environmental parameters of the dust optical concentration m value is 0.5dB/m, the light reduction rate is 10.9%/m, and the simulation of the second level of a common place is as follows: the environmental parameters of the dust optical concentration m value is 0.088dB/m, the light reduction rate is 2%/m, and the third grade of a simulated clean place is as follows: the environmental parameters of the dust optical concentration m value is 0.035dB/m, the dimming ratio is 0.8%/m, and the fourth grade of the simulated dust-free place: the optical concentration m value of the dust of the environmental parameters is less than 0.035dB/m, and the light-reducing rate is less than 0.8%/m; when two smoke detectors are subjected to level I and level II tests, the dust feeding rate is 0.19dBm ^-1min^-1≤△m/△t≤0.418dBm^-1min^-1The increase range of the dust optical concentration m value in the test box body is 0-1 dB/m, when m is 1dB/m or one smoke detector sends an alarm signal, the test is finished, and when two smoke detectors carry out III and IV grade tests, the dust feeding speed can meet 0.015dBm^-1min^-1≤△m/△t≤0.1dBm^-1min^-1The increasing range of the optical dust concentration m value in the test box body is 0-0.088 dB/m, and the test is finished when m is 0.088dB/m or one smoke detector sends out an alarm signal;

and 4, judging according to the test result: when the dust concentration in the test box body reaches the dust concentration corresponding to the optical dust concentration m value under each test grade, the two smoke detectors do not give an alarm, the fact that the smoke detectors of the type pass the grade test is shown, and the highest grade passed by the smoke detectors of the type is used as the grade of the dust transient interference resistance of the smoke detectors.

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