• Journal of the Korean Society of Safety
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• v.37 no.5
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• pp.14-21
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• 2022

The purpose of this study was to apply the signal pattern recognition technique to the digital wireless fire-alarm system and to reduce unwanted fire alarms. In this study, the fire alarms of the K Institute, which operates the largest digital wireless fire-alarm system in Korea, were classified into normal operations and unwanted fire alarms, and these were analyzed and compared with actual fire signals. In addition, by designing a non-fire signal filter and applying it to the K Institute, we confirmed that the monthly unwanted fire alarm rate of all 5,713 detectors decreased sharply. In particular, the unwanted fire alarm rate for flame decreased from 1.09% to 0.11% and the unwanted fire alarm rate for smoke decreased from 0.65% to 0.035%.

• Journal of the Korean Society of Safety
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• v.37 no.2
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• pp.69-75
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• 2022

Fire-alarm systems are safety equipment that facilitate rapid evacuation and early suppression in case of fire. It is highly desirable that fire-alarm systems have low false-alarm rates and are thus reliable. Until now, researchers have attempted to improve detector performance by applying new technologies such as IoT. To this end, IoT-based fire-detection systems have been developed. However, due to scarcity of large-scale operational data, researchers have barely studied malfunctioning in fire-alarm systems or attempted to reduce false-alarm rates in these systems. In this study, we analyzed false-alarm rates of smoke/temperature detectors and unwanted fire-alarm signal patterns at K institution, where Korea's largest IoT-based fire-detection system operates. After analyzing the fire alarm occurrences at the institution for five years, we inferred that the IoT-based fire-detection system showed lower false-alarm rates compared to the automatic fire-detection equipment. We analyzed the detection pattern by dividing it into two parts: normal operation and unwanted fire alarms. When a specific signal pattern was filtered out, the false-alarm rate was reduced to 66.9% in the smoke detector and to 46.9% in the temperature detector.

• Fire Science and Engineering
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• v.34 no.2
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• pp.30-40
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• 2020

In the event of a fire and a disaster, prompt and accurate alarms inside and outside the building are directly related to the minimization of damage and the success of life evacuation. However, due to unwanted fire alarms in automated fire detection systems, the number of dispatches by misunderstanding in the 119 service is increasing. This causes the insensitivity to the safety of building managers and the waste of the fire-fighting power. Therefore, in this study, the statistical databases and literature on unwanted fire alarms in Korea and abroad (USA, UK) were identified and the management systems for unwanted fire alarms were compared and analyzed to identify problems of statistics in the management systems for unwanted fire alarms.

• Fire Science and Engineering
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• v.22 no.4
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• pp.42-49
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• 2008

This research is to provide a scheme for an automatic fire alarm system with higher reliability through solving problems of malfunctioning (false or missing fire alarm) and power interruption (result from frequently unwanted activation, etc) of an automatic fire alarm system. A digital control system with microprocessor-based is proposed to reduce the possibility of malfunctioning through a combinational use of heat, smoke and CO sensors. Higher reliability could be achieved by these multiple sensors based fire detection system and fire distinction algorithm. In this research, we implemented actual fire detection system and conducted fire test to verify improvement on reliability.

• Fire Science and Engineering
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• v.34 no.4
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• pp.107-114
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• 2020

With the development of the national industry, the importance of the elderly and children such as the elderly, disabled, and children is recognized. Similarly, the number of facilities for the elderly and children is increasing. Fires at facilities for the elderly and children cause heavy casualties. In response to these events, it is essential to activate fire alarms promptly and accurately and to secure evacuation routes. In this study, the laws and statistics related to facilities for elderly and children were reviewed, and problems with legal terms-such as elderly, children, others, unwanted alarm of fire alarm systems, blind spots of fire compartment standards, securing evacuation routes, and absence of standards for life safety rescue organizations-were identified. As an improvement measure, the legal definitions of similar terms-such as elderly, children, unwanted alarm checklist, and establishment of standards for fire prevention compartment-and introduction of other terms-evacuation elevators, the establishment of standards for life-safety rescue organizations, and provision of flame retardation objects for evacuees-were proposed.

• Fire Science and Engineering
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• v.30 no.6
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• pp.92-98
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• 2016

This study evaluated thermal image real-time estimation and fire alarm using by a CCD camera, which has been a seamless feature-point analysis method, according to the angle and position and image fusion by a vector coordinate point set-up of equal shape. The system has higher accuracy, fixing data value of temperature sensing and fire image of 0~255, and sensor output-value of 0~5,000. The operation time of a flame specimen within 500 m, 1000 m, and 1500 m from the test report specimen took 7 s, 26 s, and 62 s, respectively, and image creation was proven. A diagnosis of fire accident was designated to 3 steps: Caution/Alarm/Fire. Therefore, a series of process and the transmission of SNS were identified. A light bulb and fluorescent bulb were also tested for a false alarm test, but no false alarm occurred. The possibility that an unwanted alarm will be reduced was verified through a forecast of the fire progress or real-time estimation of a thermal image by the change in the image of a time-based flame and an analysis of the diffusion velocity.

• Fire Science and Engineering
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• v.24 no.4
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• pp.1-11
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• 2010

This paper describes a design and implementation of an analog detector and a fire alarm system with recent technology on information and communication. A hierarchical architecture design from the detector to the main system enables to accommodate medium to large size buildings located nearby or far-away. And a software design from communication protocol to application program handles large amount of events efficiently to show information on a large LCD. A PC-based alarm system provides higher speed and larger capacity in a large LCD screen compared with foreign microprocessor-based small screen systems. Thus, very large buildings with several thousands of analog detectors can be easily covered in a single system. When an alarm occurs, a staff alarm scenario specially attempted only in the system is considered to play a major role to distinguish a real fire from unwanted alarms.

• Journal of the Society of Disaster Information
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• v.17 no.2
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• pp.236-244
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• 2021

Purpose: The purpose of this study is to develop IoT multi-fire detectors combined smoke/carbon monoxide/heat and wireless IoT communication and to confirm the detect performance by smoke generator fire test and cotton wicks fire test. Method: The IoT multi-fire detector combined smoke and CO and combined smoke and heat were experimented the detect performance by smoke generator test and fire test of cotton wicks. And the case of fire alarm was checked. Result: The IoT multi-fire detector combined smoke and CO rung the alarm at the fire test of cotton wicks, did not ring the alarm at the smoke generator test. In comparison, the IoT multi-fire detector combined smoke and heat did not ring the alarm both at the smoke generator test and the fire test of cotton wicks. Conclusion: The IoT multi-fire detector combined smoke and CO detected the only smoke including the carbon monoxide and the IoT multi-fire detector combined smoke and heat did not ring the alarm for lack of heat. As a result, when the developed IoT multi-fire detector was detected the signal more than the set point, the fire alarm was sounded through cotton wicks fire test and smoke generator.

• Journal of the Korean Society of Safety
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• v.37 no.3
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• pp.16-23
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• 2022

This study aims to provide a fundamental material for identifying fire and no-fire signals using the detection signal characteristics of IoT-based fire-detection systems. Unlike analog automatic fire-detection equipment, IoT-based fire-detection systems employ wireless digital communication and are connected to a server. If a detection signal exceeds a threshold value, the measured values are saved to a server within seconds. This study was conducted with the detection data saved from seven fire accidents that took place in traditional markets from 2020 to 2021, in addition to 233 fire alarm data that have been saved in the K institute from 2016 to 2020. The saved values demonstrated variable and continuous VC-Signals. Additionally, we discovered that the detection signals of two fire accidents in the K institution had a VC-Signal. In the 233 fire alarms that took place over the span of 5 years, 31% of smoke alarms and 30% of temperature alarms demonstrated a VC-Signal. Therefore, if we selectively recognize VC-Signals as fire signals, we can reduce about 70% of false alarms.

• Fire Science and Engineering
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• v.31 no.1
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• pp.50-57
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• 2017

The present article discusses the response characteristics of smoke detector chamber due to dust and wind velocity. Although situations have improved in terms of early sensing of fires as the smoke detectors are applied indoors, studies tend to place insufficient focus on the side effects and malfunction that can be caused by diversified life dust produced indoors and environmental requirements, etc. Therefore, in the present study, 4 types of photoelectric smoke detectors with different forms and structures of smoke chamber were selected as the experimental objects, and dust test was conducted with fly ash, talcum powder and fiber dust as experiment samples to study indoor applicability of the smoke detectors in terms of their response to diversified dust and wind velocity. Also, to observe response characteristics due to pollution level inside the smoke chamber, wind velocity for dust test were set additionally at 0.25 m/s, 0.5 m/s, and 1.0 m/s. Based to the experimental results, fly ash, talcum powder, and fiber dust (black hair powder) were found to be suitable at the dust test reference wind velocity conditions of 0.25 m/s for both operation test and non-operation test after dust application. On the other hand, under the harsh wind velocity conditions of 0.5 m/s and 1.0 m/s, malfunction of unwanted alarm was observed in non-operation tests in the case of fly ash and talcum powder, and non-operation was confirmed to occur in the case of fiber dust as the alarm failed to operate normally in operation tests.