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14 pages, 9034 KiB

Open AccessArticle

Experimental Study on Combustion Behavior of U-Shaped Cables with Different Bending Forms and Angles

by Changkun Chen, Wuhao Du and Tong Xu

Fire 2023, 6(9), 348; https://doi.org/10.3390/fire6090348 - 6 Sep 2023

Cited by 1 | Viewed by 1442

Abstract

Cables are usually bent into a U-shape to cross obstacles during installation: this includes the upward-bending mode (UBM) and the downward-bending mode (DBM). An experimental study was conducted to investigate the combustion behavior of U-shaped cables with the above bending forms and different [...] Read more.

Cables are usually bent into a U-shape to cross obstacles during installation: this includes the upward-bending mode (UBM) and the downward-bending mode (DBM). An experimental study was conducted to investigate the combustion behavior of U-shaped cables with the above bending forms and different angles. The ignition point was set in the middle of the U-shaped cables and the temperature distribution, flame spread rate (FSR), mass loss rate (MLR), flame dimensional characteristics, etc. were measured and analyzed. The results showed that FSR and MLR are positively related to the bending angles, and the FSR is the highest in UBM 90°, close to 6.51 cm/min, which is four times higher than that in the bending angle 0° condition. In the UBM, the heat radiation and convection from the cable flame to the unburned region were more intense and the “eruptive fire phenomenon” occurred during the combustion process, leading to a sharp increase in the FSR in a short time. However, the thermal convection and radiation from the burning region to the unburned region were weakened in the DBM. Meanwhile, the molten outer sheath (PE) would flow along the cables, heating and igniting the unburned region in the DBM. In addition, the FSR, MLR, and peak temperature increased in the UBM compared to the DBM. The highest flame temperature occurred in UBD 90°, approximately 1023 °C. Full article

(This article belongs to the Special Issue Fire Detection and Public Safety)

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20 pages, 9771 KiB

Open AccessArticle

Indoor Air Quality Sensor Utilization for Unwanted Fire Alarm Improvement in Studio-Type Apartments

by Han-bit Choi, Euy-hong Hwang and Don-mook Choi

Fire 2023, 6(7), 255; https://doi.org/10.3390/fire6070255 - 29 Jun 2023

Cited by 3 | Viewed by 1798

Abstract

Smoke detectors play a vital role in evacuation and safety during fire incidents, as they directly contribute to the reliability and accuracy of firefighting systems. However, if not installed properly, smoke detectors can trigger unwanted fire alarms (UWFAs), particularly in studio-type apartments. Therefore, [...] Read more.

Smoke detectors play a vital role in evacuation and safety during fire incidents, as they directly contribute to the reliability and accuracy of firefighting systems. However, if not installed properly, smoke detectors can trigger unwanted fire alarms (UWFAs), particularly in studio-type apartments. Therefore, this study aimed to develop a method for reducing UWFAs by addressing the challenges posed by cooking by-products in such environments. The proposed algorithm was validated through tests, considering relevant literature and standards, and utilizing indoor air quality sensors. Verification tests were conducted to enhance the accuracy of the algorithm. Based on the experimental results, cutoff values of 5 ppm for CO and 7000 μg/m³ for PM10.0 were proposed as criteria for identifying UWFAs caused by cooking by-products. Full article

(This article belongs to the Special Issue Fire Detection and Public Safety)

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14 pages, 2061 KiB

Open AccessArticle

Study on Location of Fire Stations in Chemical Industry Parks from a Public Safety Perspective: Considering the Domino Effect and the Identification of Major Hazard Installations for Hazardous Chemicals

by Junhao Jiang, Xiaochun Zhang, Ruichao Wei, Shenshi Huang and Xiaolei Zhang

Fire 2023, 6(6), 218; https://doi.org/10.3390/fire6060218 - 27 May 2023

Cited by 3 | Viewed by 2084

Abstract

In order to select the location of fire stations more scientifically and improve the efficiency of emergency management in chemical industry parks (CIPs), an improved risk calculation model for hazardous chemicals has been proposed by taking the domino effect and the identification of [...] Read more.

In order to select the location of fire stations more scientifically and improve the efficiency of emergency management in chemical industry parks (CIPs), an improved risk calculation model for hazardous chemicals has been proposed by taking the domino effect and the identification of major hazardous installations for hazardous chemicals into account. In the analysis of the domino effect, the Monte Carlo simulation was used. Then, a location model of the fire stations was established with the optimization objectives of minimizing total cost and maximizing total risk coverage. The solving procedure of the location model is based on the augmented

ε

-constraint method combined with the TOPSIS method. Finally, a green chemical industry park was used as a case study for the validation and analysis of the location model. The results showed that the improved model could protect the high-risk areas, which is beneficial for the location decisions of fire stations. Full article

(This article belongs to the Special Issue Fire Detection and Public Safety)

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13 pages, 5860 KiB

Open AccessArticle

Improved Particle Swarm Path Planning Algorithm with Multi-Factor Coupling in Forest Fire Spread Scenarios

by Kaiyi Lin, Lifan Zhang, Lida Huang, Zhili Feng and Tao Chen

Fire 2023, 6(5), 202; https://doi.org/10.3390/fire6050202 - 13 May 2023

Cited by 2 | Viewed by 1787

Abstract

In this paper, a solution based on an improved particle swarm algorithm is proposed for the path planning problem without a road network in forest fire rescue scenarios. The algorithm adopts an adaptive inertia weight and a dynamically updated learning factor strategy to [...] Read more.

In this paper, a solution based on an improved particle swarm algorithm is proposed for the path planning problem without a road network in forest fire rescue scenarios. The algorithm adopts an adaptive inertia weight and a dynamically updated learning factor strategy to enhance the global and local search capabilities of the algorithm. In terms of cost function design, the article considers three factors: path length, terrain slope, and obstacle avoidance ability to ensure the safety and effectiveness of the path. The experimental results show that: (1) the path planning algorithm based on improved particle swarm optimization can effectively avoid spreading wildfire and reach the designated target point with a good “detour” effect; (2) the path planned by the improved PSO algorithm performs better than the original PSO algorithm in terms of fitness evaluation and average slope; and (3) changes in the particle population, dimensions, and learning factors in the particle swarm optimization algorithm can affect the convergence of the final path. Increasing the particle dimensions can bring more reasonable and specific paths; decreasing the learning factor increases the convergence iterations, but also obtains a better path planning solution and higher fitness. Full article

(This article belongs to the Special Issue Fire Detection and Public Safety)

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18 pages, 7896 KiB

Open AccessArticle

Dual-Wavelength Smoke Detector Measuring Both Light Scattering and Extinction to Reduce False Alarms

by Kaiyuan Li, Gang Liu, Hongyong Yuan, Yang Chen, Yunzhi Dai, Xiangrui Meng, Yuxin Kang and Lida Huang

Fire 2023, 6(4), 140; https://doi.org/10.3390/fire6040140 - 1 Apr 2023

Cited by 6 | Viewed by 4478

Abstract

Existing fire smoke detectors use the intensity of scattering light or the light extinction coefficient as the indicator of fire smoke to trigger fire alarms. However, false fire alarms could be triggered by dust and water fog. Achieving reliable early fire detection with [...] Read more.

Existing fire smoke detectors use the intensity of scattering light or the light extinction coefficient as the indicator of fire smoke to trigger fire alarms. However, false fire alarms could be triggered by dust and water fog. Achieving reliable early fire detection with minimal false alarms is a challenge. Based on the Mie scattering theory of spherical particles, it is derived that the ratio of scattering intensity and the ratio of optical extinction of two incident lights with different wavelengths only depends on the intrinsic properties of the aerosol (the average particle size and refractive index). This paper then presents an improved dual-wavelength smoke detection by measuring scattering light and extinction simultaneously to reduce false alarms. Simulations and verification with test fires of European Standard EN 54 were performed, demonstrating that fires can be distinguished from nuisance sources without complicated calculations. These results indicate that the improved detection system can be applied for smoke monitoring and fire protection. Full article

(This article belongs to the Special Issue Fire Detection and Public Safety)

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23 pages, 8467 KiB

Open AccessArticle

Optimization of Smoke-Detector Installation Location Based on Effect of Fan Equipment inside Distribution Panel on Fire Detection Performance

by In-Mo Gu, Yeong-Mo Yeon, Dong-Seok Ryu and Seung-Hee Kim

Fire 2023, 6(2), 49; https://doi.org/10.3390/fire6020049 - 28 Jan 2023

Cited by 2 | Viewed by 3832

Abstract

Inhalation and exhaust fans are installed inside a distribution panel for cooling. However, in the event of fire inside the panel, these fans change the flow of smoke, which interferes with quick detection by fire sensors installed on the panel ceiling, thereby increasing [...] Read more.

Inhalation and exhaust fans are installed inside a distribution panel for cooling. However, in the event of fire inside the panel, these fans change the flow of smoke, which interferes with quick detection by fire sensors installed on the panel ceiling, thereby increasing fire damage. The purpose of this study is to develop a smoke detector that can be installed inside distribution panels and to propose an optimal smoke detector position based on the influence of the position on detection performance. To this end, an experimental distribution panel was fabricated and four smoke detector samples were installed near the fans. The smoke detection performance experiment was repeated on ignition source positions corresponding to widths of 15, 30, 45, and 50 cm, a depth of 55 cm, and heights of 0, 30, and 60 cm. The results indicated that the smoke detection performance and CO absorption concentration were higher when the smoke detector was positioned closer to the left or right side of the exhaust fan. In particular, compared with current designs in which smoke detectors are installed on distribution panel ceilings, the elapsed time until smoke detection decreased by 75%, whereas the CO absorption concentration increased by more than 100%. This study presents a theoretical ground for the installation of built-in smoke detectors near exhaust fans for closed power industry equipment that includes airflow-changing devices. Additionally, this study raises awareness on the importance of fire sensors and the need to improve policies and standards for fire prevention. Full article

(This article belongs to the Special Issue Fire Detection and Public Safety)

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Other

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21 pages, 6553 KiB

Open AccessTechnical Note

A Prediction Model for Smoke Spread Path in High Rise Building Fires Based on Graph Theory

by Haoyou Zhao, Zhaoyang Yu and Jinpeng Zhu

Fire 2023, 6(7), 258; https://doi.org/10.3390/fire6070258 - 30 Jun 2023

Cited by 3 | Viewed by 2001

Abstract

To satisfy the demand for rapid prediction of smoke transmission paths in high-rise building fires, a graph-based model was developed. The model represents a high-rise building as a Directed Acyclic Graph (DAG) grid model and employs computer simulation to determine the smoke transmission [...] Read more.

To satisfy the demand for rapid prediction of smoke transmission paths in high-rise building fires, a graph-based model was developed. The model represents a high-rise building as a Directed Acyclic Graph (DAG) grid model and employs computer simulation to determine the smoke transmission path and generate prediction results. The results were compared with those from similar simulations and were found to be consistent, indicating the feasibility and objective nature of the prediction results. Compared to other methods, this model has a shorter modeling time and can quickly provide prediction results. Furthermore, it can be applied to buildings of any structure, thus serving as a reference for smoke control design in high-rise building fire protection systems, particularly in cases involving complex internal structures. Full article

(This article belongs to the Special Issue Fire Detection and Public Safety)

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15 pages, 6328 KiB

Open AccessTechnical Note

Development and Experimental Study of Mobile Fire Smoke Decontamination System

by Hongyong Yuan, Yang Zhou, Fan Zhou, Lida Huang and Tao Chen

Fire 2023, 6(2), 55; https://doi.org/10.3390/fire6020055 - 3 Feb 2023

Viewed by 1680

Abstract

Fire smoke decontamination equipment, such as fire-fighting robots and smoke exhaust robots, is mainly used in long and narrow spaces such as underground garages. In several recent decades, the study of fire smoke spread in narrow spaces and fire smoke decontamination equipment stimulated [...] Read more.

Fire smoke decontamination equipment, such as fire-fighting robots and smoke exhaust robots, is mainly used in long and narrow spaces such as underground garages. In several recent decades, the study of fire smoke spread in narrow spaces and fire smoke decontamination equipment stimulated the interests of many researchers. However, present equipment cannot eliminate insoluble toxic gases such as CO and may decrease the height of the smoke layer, causing great difficulty to rescue. In this study, a novel mobile fire smoke decontamination process and system are proposed. The experimental study and theoretical prediction of the system are conducted. The results show that the developed equipment is able to eliminate fire smoke particles and CO, cool the space, and improve the visibility of the fire site. The developed equipment can reduce the space temperature to below 60 °C, reduce the CO concentration to below 145 ppm, and enhance the visibility to more than 50 m in the rectangular tunnel after operating for 30 min under 4 MW fire condition. Full article

(This article belongs to the Special Issue Fire Detection and Public Safety)

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