A case study on using the FDS tool for on-site fire investigation

When investigating a fire type event, one has to have in mind that maybe the most important aspect is the identification of the source of ignition. Nowadays, commercial and open-source software are available and can be used during such investigations. The fire field model - Fire Dynamics Simulator (FDS) is one of the most popular numerical model used for fire investigation. The purpose of this paper is to demonstrate the importance of computer simulations when two hypotheses, Arson effect with multiple fireplaces and electric short circuit are taken into consideration as the cause of the fire. To virtually simulate the findings at the fire site, the FDS tool (Computational Fluid Dynamics) was used. Computational simulations for the two scenarios revealed that the multiple fireplaces scenario, the initial ignition at both the warehouse and the roof of the annex, illustrates the effects of the fire in a similar way to those found at the site, while the scenario with the initial source on the wall of the room with the electrical panel produces a fire located at the level of the construction and is not transmitted to the annex. Consequently, the results obtained validate the multiple outbreak (Arson effect) scenario.

Влияние алгоритма взаимодействия автоматических установок пожаротушения и противодымной вентиляции на время блокирования эвакуационных путей и эффективность локализации пожара в помещениях высокостеллажного хранения

Цель. На основе численного моделирования пожара в помещении склада с высотным стеллажным хранением определить оптимальный алгоритм взаимодействия автоматических установок пожаротушения (АУПТ) и противодымной вентиляции (ПДВ) по времени блокирования эвакуационных путей и эффективности локализации пожара. Методы. В работе применены теоретические методы исследования (анализ, синтез, сравнение), а также выполнено численное моделирование в расчетном программном комплексе Fire Dynamics Simulator. Результаты. В результате численного моделирования пожара в помещении склада с высотным стеллажным хранением резинотехнических изделий размерами 60×50×14 м и высотой складирования пожарной нагрузки 12,5 м определен оптимальный алгоритм взаимодействия АУПТ и ПДВ по времени блокирования эвакуационных путей и эффективности локализации пожара, а именно: оросители АУПТ размещаются только во внутристеллажном пространстве, при этом запуск противодымной вентиляции производится от АУПТ. Данная схема защиты позволяет локализовать очаг пожара без распространения на соседние стеллажи и удерживать его мощность на минимальном уровне, а также увеличить время блокирования продуктами горения и термического разложения путей эвакуации в горизонтальной плоскости помещения на высоте 1,7 м в среднем в 1,3 раза и эвакуационного выхода в той же плоскости в 1,7–2,9 раза по сравнению с иными вариантами взаимодействия АУПТ и ПДВ. Область применения исследований. Полученные результаты могут быть использованы для определения алгоритмов взаимодействия составных элементов систем пожарной автоматики при защите складов с высотным хранением материалов.

Experimental and Modeling Uncertainty Considerations for Determining the First Item Ignited in a Compartment Using a Bayesian Method

Fire scene reconstruction and determining the fire evolution (i.e. item-to-item ignition events) using the post-fire compartment is an extremely difficult task because of the time-integrated nature of the observed damages. Bayesian methods are ideal for making inferences amongst hypotheses given observations and are able to naturally incorporate uncertainties. A Bayesian methodology for determining probabilities to items that may have initiated the fire in a compartment from damage signatures is developed. Exercise of this methodology requires uncertainty quantification of these damage signatures. A simple compartment configuration was used to quantify the uncertainty in damage predictions by Fire Dynamics Simulator (FDS), and a compartment evolution program, JT-risk as compared to experimentally derived damage signatures. Surrogate sensors spaced within the compartment use heat flux data collected over the course of the simulations to inform damage models. Experimental repeatability showed up to 4% uncertainty in damage signatures between replicates . Uncertainties for FDS and JT-risk ranged from 12% up to 32% when compared to experimental damages. Separately, the evolution physics of a simple three fuel package problem with surrogate damage sensors were characterized in a compartment using experimental data, FDS, and JT-risk predictions. An simple ignition model was used for each of the fuel packages. The Bayesian methodology was exercised using the damage signatures collected, cycling through each of the three fuel packages, and combined with the previously quantified uncertainties. Only reconstruction using experimental data was able to confidently predict the true hypothesis from the three scenarios.

Assessment Of LNG Bunkering Accidents

The maritime safety is of great concern for the entire maritime community. Ships using LNG for propulsion are already sailing the seas, but the majority of the ports are not yet prepared for this kind of supply. As the process of LNG bunkering is only seemingly similar to traditional oil bunkering or liquid loading, dealing with the technical and safety challenges is much more subject of investigation. In this paper, the dispersion part of the consequences of LNG release, pooling, evaporation and dispersion during the future bunkering operation in the port of Koper, Slovenia, where the populated area (city) is located in close proximity are examined. We follow the comparison of three different tools, namely the Unified Dispersion Model (UDM) implemented by the software PHAST from DNV-GL® and two CFD (FDS – Fire Dynamics Simulator from NIST and Ansys Fluent®) in the same case scenario. Geometry, initial and boundary conditions are assumed to be the same as far as possible, according to the limitations of the respective software tools.

Computational modeling of fire safety in metro-stations

This research investigates and attempts to quantify the hazards associated with fire in metrostations. The use of numerical simulations for the analysis of fire safety within metro-stations allows for the prediction and analysis of hazards within the built environment. Such approaches form the growing basis of performance based design (PBD), which can optimize design solutions. The simulations utilize Fire Dynamics Simulator (FDS), a Computational Fluid Dynamics (CFD) model and Pathfinder, an evacuation modeling software. The safety of underground metro-stations is analyzed through the simulation of smoke spread and egress modelling. CFD models of TTC’s Union Station and TransLink’s Yaletown Station are developed to allow for simulations of smoke spread scenarios. These models are evaluated in regards to the preservation of tenability and influence on the Available Safe Egress Time (ASET). The egress of metro-stations is modelled and analyzed to determine the Required Safe Egress Time (RSET).

Computational modeling of fire safety in metro-stations

This research investigates and attempts to quantify the hazards associated with fire in metrostations. The use of numerical simulations for the analysis of fire safety within metro-stations allows for the prediction and analysis of hazards within the built environment. Such approaches form the growing basis of performance based design (PBD), which can optimize design solutions. The simulations utilize Fire Dynamics Simulator (FDS), a Computational Fluid Dynamics (CFD) model and Pathfinder, an evacuation modeling software. The safety of underground metro-stations is analyzed through the simulation of smoke spread and egress modelling. CFD models of TTC’s Union Station and TransLink’s Yaletown Station are developed to allow for simulations of smoke spread scenarios. These models are evaluated in regards to the preservation of tenability and influence on the Available Safe Egress Time (ASET). The egress of metro-stations is modelled and analyzed to determine the Required Safe Egress Time (RSET).

Examination on Effects of Spray Characteristics of Water Mist on Thermal Radiation Attenuation Using Fire Dynamics Simulator

In this study, numerical simulations to investigate the effects of the spray characteristics of water mist on thermal radiation attenuation were performed using fire dynamics simulator (FDS). The droplet size, flow rate, and spray angle of the water mist were 100-300 µm, 1-3 L/min, and 60-180°, respectively. As the droplet size decreased and flow rate increased, the thermal radiation attenuation increased. When the spray angles decreased and increased behind the near nozzle center and behind a certain remote distance from the nozzle center, respectively, the thermal radiation attenuation increased. The peak thermal radiation attenuation increased with decreases in droplet size and spray angle and an increase in flow rate, whereas the average thermal radiation attenuation increased with a decrease in droplet size and increases in flow rate and spray angle. Under the numerical simulation conditions of this study, the peak and average thermal radiation attenuations were significantly altered by the ratios of droplet size and flow rate and by that of flow rate, respectively. However, their variations with the ratio of spray angle were the smallest.

Control method of mechanical smoke emission in high-rise building corridor

The traditional method has a large control error in the corridor mechanical smoke control method. Therefore, a multi-task convolutional neural network-based high-rise building corridor mechanical smoke control method is proposed. Through the mechanical smoke exhaust principle of high-rise building corridors, the threshold of mechanical smoke exhaust is set to predict the mechanical smoke exhaust volume of high-rise building corridors. The movement of mechanical smoke in high-rise building corridors is simulated according to fire dynamics simulator to determine the turbulence state of mechanical smoke in high-rise building corridors. Input the mechanical smoke exhaust data of high-rise building corridors into the multi-task convolutional neural network to complete the mechanical smoke exhaust control of high-rise building corridors. Experimental results show that the maximum accuracy of this method is about 98%, and the control time is always less than 1 second.