• Fire Science and Engineering
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• v.23 no.5
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• pp.133-137
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• 2009

The Fire Dynamics Simulator (FDS), a computational fluid dynamics model for fire simulation, was applied to propylene vertical wall fires, to confirm its accuracy in simulation of vertical wall fires. The temperature profiles at the center of the burner obtained for mass loss rates per unit area in the range of $7.0{\sim}29.29g/m^2-s$ were compared with those of experiment. Comparisons of the heat flux distributions along the vertical centerline on the wall surface were made with the measurements. It was shown that the computed temperature profiles were in good agreement with the experiment. It was also noted that the peak temperature near the wall was underpredicted, the heat flux was too high compared with the measurements, and hence improvements are required for FDS in simulation of the vertical wall fires.

• Fire Science and Engineering
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• v.32 no.4
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• pp.75-85
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• 2018

The Grenpell tower fire in England in June of 2016 is a representative example of damage caused by a vertical fire spreading through external insulation. Organic insulation materials, which are widely used in external insulation, have the disadvantage that they have good insulation performance but are vulnerable to fire. Aluminum composite panels are used as exterior wall finishing materials, and plastics used in aluminum are regarded as the cause of vertical fire spread. Due to the steel frame used to secure the aluminum composite panel to the outer wall, a cavity is formed between the outer wall and outer wall finish. When a fire occurs on the outer wall, the flammable outer wall as well as the flame generated from the heat-insulating material spreads vertically through the cavity, resulting in damage to people and property. In Korea, material unit performance tests are carried out by the Ministry of Land, Infrastructure and Transport notice 2015 - 744. However, in the UK, the BS 8414 test is used to measure the vertical fire spreading time on the outer wall in real scale fire tests. In this study, the risk of external wall fire was evaluated in an actual fire by conducting a real scale wall fire test (BS 8414), which was carried out in Europe, using aluminum composite panels of semi-noncombustible materials suitable for current domestic standards. The purpose of this study was to confirm the limitations of material unit evaluation of finishing materials and to confirm the necessity of introducing a system to prevent the spread of outer wall fire through an actual scale fire test.

• Fire Science and Engineering
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• v.22 no.3
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• pp.188-193
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• 2008

Numerical simulation was carried out for a propane fire of mass transfer rate 3g/m^2-s$ on a 1m high vertical wall. The objectives of this study are to confirm the outcomes of evaluation of the simulator through simulation of natural convection, and to compare the results of the wall fire with those of previous studies. It was confirmed that the simulated boundary layer was laminar at C_s=0.2$ while it was turbulent at C_s=0.1$. The z direction velocity showed lack of turbulent mixing as seen in the natural convection case, and the profiles of temperature and velocities were in relatively good agreement with those of experiment and previous simulation. It was found that the air entrainment into the boundary layer was well predicted.

• Fire Science and Engineering
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• v.22 no.3
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• pp.181-187
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• 2008

Numerical simulation of natural convection along a vertical wall was carried out to evaluate the computational fluid dynamics simulator, which is to be utilized for study of vertical wall fires. The computed velocity and temperature profiles were compared with measurements over the turbulent boundary layer formed along the wall of 4m high and constant temperature. It fumed out that the simulator with default parameters failed to predict the turbulent natural convection showing the boundary layer flow laminar. The grid size $\Delta$x=5mm, ${\Delta}y={\Delta}z=10mm$ and Smagorinsky constant of the large eddy simulation $C_s$=0.1 were chosen through parametric investigations. Though turbulent mixing was not enough, the velocity distribution near wall, peak velocity, and temperature profile in the turbulent boundary layer agreed well with the measurements.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.3
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• pp.267-281
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• 1994

The Combustion gas behavior induced by fire in a building is numerically investigated. The typical building for this analysis is partially divided by a vertical baffle projecting from the ceiling. The solution procedure includes the low Reynolds number ${\kappa}-{\varepsilon}$ model for the turbulent flow and the discrete ordinates method is used for the calculation of radiative heat transfer equation. The effects of the location and size of fire source and baffle length on velocity and temperature distributions, species mass fraction and flame location are analyzed. As the results of this study, it is found that the case when the fire source is located at the vertical wall is more dangerous than at the bottom wall in view of the combustion products and flame location. It is also found that the radiation effect cannot be neglected in analyzing the building in fire.

• Journal of computational fluids engineering
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• v.21 no.4
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• pp.1-10
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• 2016

The analysis of characteristics of turbulent flow and thermal boundary layer for natural convection caused by fire along vertical wall is performed. The 4m-high vertical copper plate is heated and kept at a uniform surface temperature of $60^{\circ}C$ and the surrounding fluid (air) is kept at $16.5^{\circ}C$. The flow and temperature is solved by large eddy simulation(LES) of FDS code(Ver.6), in which the viscous-sublayer flow is calculated by Werner-Wengle wall function. The whole analyzed domain is assumed as turbulent region to apply wall function even through the laminar flow is transient to the turbulent flow between $10^9$<$Gr_z$<$10^{10}$ in experiments. The various grids from $7{\times}7{\times}128$ to $18{\times}18{\times}128$ are applied to investigate the sensitivity of wall function to $x^+$ value in LES simulation. The mean velocity and temperature profiles in the turbulent boundary layer are compared with experimental data by Tsuji & Nagano and the results from other LES simulation in which the viscous-sublayer flow is directly solved with many grids. The relationship between heat transfer rate($Nu_z$) and $Gr_zPr$ is investigated and calculated heat transfer rates are compared with theoretical equation and experimental data.

• Fire Science and Engineering
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• v.32 no.6
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• pp.69-73
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• 2018

This study examined the reduction effect of a hydrodynamic force acting on the vertical wall of a portable water storage tank with a convex bottom floor. For the numerical simulation, the linearized Peregrine's equation was used to analyze the lapping waves in the tank caused by water falling from a supplying nozzle. The hydrodynamic force could be calculated by measuring the maximum run-up wave height at the vertical wall. The initial conditions of the numerical experiments were set up by controlling the positions and heights of the water supplying nozzle. Finally, the hydrodynamic force acting on the vertical wall can be reduced by the convex bottom design of the portable water storage tank so it can be applied to improve the structural stability.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.15-18
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• 2008

A study on the fire and smoke behavior on experiments and analysis through STAR-CD in using about behavior analysis of the smoke. Kerosene of 3L in using on the experimental garden of 30cm in diameter same applies to heat release rate(HRR), buoyant force by Plume can be calculated at a rate of 1m/s. The result of experiment in average of velocity were 0.29m/s, and interpreted result were 0.28m/s. Besides, it is proved by interpreted that behavior of smoke movement can be not observed in the experiment. After smoke is Plume increased, ceiling-jet in formation being descend in smoke layer will be more thick smoke layer, and then vertical wall is collapsed in formation of wall-jet being descend. It is defined that smoke layer is more thick through descending course in wall-jet and ceiling-jet.

• Fire Science and Engineering
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• v.22 no.4
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• pp.1-10
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• 2008

In this study, the effects of vent location, outside temperature, wind velocity and fire size on the performance of natural venting of the vertical vent designed according to NFPA 204 standard and fire characteristics were numerically investigated using CFAST. In cases of the Vent located on most upper wall, lower outside temperature and lower wind velocity, vents met the performance criteria of venting. The larger fire size becomes, the more mass flow rate through a vent becomes, but the lower interface height of smoke layer becomes, so that vent didn't meet the performance criteria of venting. It should be noted that a natural vertical vent be designed considering maximum outside temperature and maximum wind velocity and developing a design fire accurately in order to meet the performance criteria of venting.

• Architectural research
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• v.24 no.2
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• pp.21-27
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• 2022

For the past decade, South Korea had experienced catastrophic building fires, which resulted in consider-ably high number of casualties. This motivated research to develop fire-safe wall assemblies. In this study Fire Risk Analysis (FRA) is conducted as part of the project designing phase to ensure fire safety of the final product. Traditional approach was to consider fire performance at the end of the designing stage, when PASS/FAIL fire test results are required to be submitted to the Authority Having Jurisdiction (AHJ). By applying a fire risk analysis to guide the designing phase, overall fire safety of a wall assembly can be achieved more systematically as conducting FRA allows designers to clearly identify elements that are more vulnerable to fire and simply replace them with other practical options. Severity of fire risk is determined by considering the fire hazards of a wall assembly such as the exterior layer, insulation, vertical connectivity, and external ignition sources (e.g., photovoltaic panels). Frequency of fire risk is assessed based on the factors affecting fire likelihood, which are air cavity and fire-stopping applied in the design, and random design changes occurring during on-site construction. Fire risk matrix is proposed based on these fire risk factors and efforts to reduce the fire risk level associated with the wall assembly are given by systematically assessing the fire risk factors identified from fire risk analysis. Current study demonstrates how fire risk analysis can be applied to develop fire-safe walls by reducing the relevant fire risks- both severity and frequency.