The present study, for the sensitivity of a smoke detector to the black smoke occurred by the characteristic of fire in UL 268, has used a combustion gas meter, an analogue photoelectric smoke detector, a fine dust meter, and an optical densitometer at the fire experiment center presented in UL 268;...
The present study, for the sensitivity of a smoke detector to the black smoke occurred by the characteristic of fire in UL 268, has used a combustion gas meter, an analogue photoelectric smoke detector, a fine dust meter, and an optical densitometer at the fire experiment center presented in UL 268; and confirmed the characteristics of the detection of black smoke. Regardless of enormous amount of smoke, it seems difficult for the smoke detector to reach the concentration of 15 %/m for fire detection through two types of experiment. Such phenomenon has actually confirmed a fire of poly-urethane foam that generates black smoke as the inner champer of the smoke detector has a black labyrinth structure and a lower possibility of scattering by the smoke at the fire of inflammable liquid. Therefore, as it is judged difficult to detect the fire only with the smoke detector at the fire of polyurethane foam and inflammable liquid, in order to check the amount of change in various combustion products that are generated at the fire and to raise the reliability of the fire detector, among the experiments in actual fire regulated by UL 268, the following results have been deduced through the experiment in the fire of Polyurethane foam and Flammable liquid.
1. As two experiments of Flammable liquid and Polyurethane foam are flaming combustion existed as soon as both experiments in fire begin, it is judged that CO was generated faster than CO2. However, in case of the experiment in the fire of Flammable liquid, as the combustible is a strong volatile liquid, substance is not burned directly but steam is ignited by the flame. It is therefore judged that combustion products may be generated faster if specimen is spread more widely.
2. Even though the measuring location of CO2 is a ceiling, the Flammable liquid shows about 1.6 times and the Polyurethane foam about 3.5 times higher value than 1,000ppm which is the standard for the control law of indoor air quality. In an actual situation of fire, there is a very high possibility to generate much CO2. It is presumed that the fire may be detected at the rapid change in the numerical value of CO2.
3. From the results of the experiments in the fire of Polyurethane and Flammable liquid, combustion products were generated or measured later than smoke. Such phenomena are judged to be the movement by the buoyancy of flame as they are heavier than the air. Yet, if these elements that are generated late are applied and utilized for the elements to judge possible malfunction after the fire detection, it is judged that it will be possible to secure the reliability of the detector by minimizing the malfunction.
4. It has been confirmed that gases measured by the combustion gas meter at the fire of Polyurethane foam and Flammable liquid were measured later than the flow time of smoke. Such phenomenon is judged difficult for measurement as a substance heavier than the air rises to the installation location of ceiling. If the characteristic of such elements detected later is identified and utilized for the elements to judge possible malfunction after the fire detection, the detector will become highly reliable by minimizing the malfunction.
In the future, based on the present study, not only using Polyurethane foam and Flammable liquid, but based on the average value of each combustible measured for each concentration, if various combustibles would be used to measure combustion products simultaneously through the experiment in fire with 7.5 %/m of operation concentration of the first class smoke detector; and if a study is conducted on a detector that can carry out faster and precise fire detection to be used easily for public places, household, and diverse commercial facilities, the capability of the detector will be maximized, which in turn will minimize the damage on the life, body, and property of citizens.
The present study, for the sensitivity of a smoke detector to the black smoke occurred by the characteristic of fire in UL 268, has used a combustion gas meter, an analogue photoelectric smoke detector, a fine dust meter, and an optical densitometer at the fire experiment center presented in UL 268; and confirmed the characteristics of the detection of black smoke. Regardless of enormous amount of smoke, it seems difficult for the smoke detector to reach the concentration of 15 %/m for fire detection through two types of experiment. Such phenomenon has actually confirmed a fire of poly-urethane foam that generates black smoke as the inner champer of the smoke detector has a black labyrinth structure and a lower possibility of scattering by the smoke at the fire of inflammable liquid. Therefore, as it is judged difficult to detect the fire only with the smoke detector at the fire of polyurethane foam and inflammable liquid, in order to check the amount of change in various combustion products that are generated at the fire and to raise the reliability of the fire detector, among the experiments in actual fire regulated by UL 268, the following results have been deduced through the experiment in the fire of Polyurethane foam and Flammable liquid.
1. As two experiments of Flammable liquid and Polyurethane foam are flaming combustion existed as soon as both experiments in fire begin, it is judged that CO was generated faster than CO2. However, in case of the experiment in the fire of Flammable liquid, as the combustible is a strong volatile liquid, substance is not burned directly but steam is ignited by the flame. It is therefore judged that combustion products may be generated faster if specimen is spread more widely.
2. Even though the measuring location of CO2 is a ceiling, the Flammable liquid shows about 1.6 times and the Polyurethane foam about 3.5 times higher value than 1,000ppm which is the standard for the control law of indoor air quality. In an actual situation of fire, there is a very high possibility to generate much CO2. It is presumed that the fire may be detected at the rapid change in the numerical value of CO2.
3. From the results of the experiments in the fire of Polyurethane and Flammable liquid, combustion products were generated or measured later than smoke. Such phenomena are judged to be the movement by the buoyancy of flame as they are heavier than the air. Yet, if these elements that are generated late are applied and utilized for the elements to judge possible malfunction after the fire detection, it is judged that it will be possible to secure the reliability of the detector by minimizing the malfunction.
4. It has been confirmed that gases measured by the combustion gas meter at the fire of Polyurethane foam and Flammable liquid were measured later than the flow time of smoke. Such phenomenon is judged difficult for measurement as a substance heavier than the air rises to the installation location of ceiling. If the characteristic of such elements detected later is identified and utilized for the elements to judge possible malfunction after the fire detection, the detector will become highly reliable by minimizing the malfunction.
In the future, based on the present study, not only using Polyurethane foam and Flammable liquid, but based on the average value of each combustible measured for each concentration, if various combustibles would be used to measure combustion products simultaneously through the experiment in fire with 7.5 %/m of operation concentration of the first class smoke detector; and if a study is conducted on a detector that can carry out faster and precise fire detection to be used easily for public places, household, and diverse commercial facilities, the capability of the detector will be maximized, which in turn will minimize the damage on the life, body, and property of citizens.
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