scholarly journals NUMERICAL STUDIES ON SMOKE SPREAD IN THE CAVITY OF A DOUBLE-SKIN FAÇADE / SKAITINIS DŪMŲ SKLIDIMO DVIGUBO FASADO ERTMĖJE TYRIMAS

2011 ◽  
Vol 17 (3) ◽  
pp. 371-392 ◽  
Author(s):  
Cheuk Lun Chow
Keyword(s):  
Fire Hazard ◽  
Vertical Channel ◽  
Fire Dynamics ◽  
Cavity Depth ◽  
Air Cavity ◽  
Numerical Studies ◽  
Architectural Feature ◽  
Smoke Spread ◽  
Double Skin ◽  
Level Model

Double-skin façade (DSF) is an environmental friendly architectural feature. However, fire hazard is a concern. A scenario of having a flashover room fire adjacent to the façade was identified. Heat and mass would be trapped in the façade cavity. This paper examines air flow driven out of a flashover room fire to the cavity of a DSF by Computational Fluid Dynamics. The software Fire Dynamics Simulator developed at the Building and Fire Research laboratory, National Institute of Standards and Technology, USA was selected as the simulation tool. Three DSF features labeled as DSF1, DSF2 and DSF3 were considered. Detailed simulations were carried out to understand the fire-induced aerodynamics in a 5-level model DSF1 with a fire room at the third level. Hot gas spreading out to the façade cavity was simulated under two heat release rates of 1 MW and 5 MW. Air cavity depths of 0.5 m, 1 m, 1.5 m and 2 m were considered. Three stages of flame spreading out to a DSF with a wide air cavity depth were identified. Results suggested that wider air cavity depths would be more dangerous, with higher risk of the upper interior glass pane's breaking. To study spreading of heat and mass up the façade cavity as vertical channel flow, two taller DSF façade features DSF2 and DSF3 with differing air cavity depths were simulated. Both features were of height 24 m but of differing fire room height. Vertical temperature profiles with and without the DSF feature were compared. Santrauka Dvigubas fasadas yra ekologiškas architektūrinis sprendimas. Tačiau dvigubas fasadas yra problemiškas gaisrinės saugos požiūriu. Nagrinėjamas scenarijus, kai greta dvigubo fasado esančioje patalpoje įvyksta gaisro pliūpsnis. Dvigubo fasado ertmėje gali būti uždaryti karštis ir masė. Taikomi skaitmeninės skysčių dinamikos metodai nustatyti, kaip iš patalpos, kurįoje įvyksta gaisro pliūpsnis, oras ir degimo produktai išstumiami ī dvigubo fasado ertmę. Modeliuoti naudojama kompiuterinė programa, parengta JAV Nacionaliniame standartų ir technologijos institute. Nagrinėjami trys dvigubų fasadų sprendimai. Atliekamas detalus pirmojo sprendimo fasado modeliavimas siekiant suprasti gaisro lemiamą aerodinamiką penkių aukštų fasade, kai gaisras kyla trečiame aukšte. Modeliuojamas karštu dujų sklidimas iš fasado ertmės viršaus teigiant, kad gaisro išskiriama Siluma yra 1 MW ir 5 MW. Ertmės plotis imamas lygiu 0,5 m, 1,5 m ir 2 m. Nustatomi trys liepsnos sklidimo iš dvigubo fasado etapai. Gauti rezultatai leidžia daryti išvadą, kad platesni fasadai yra pavojingesni, nes didina viršutinių stiklo diskų dužimo tikimybę. Aukštesni antro ir trečio sprendimo fasadai naudoti tirti, kaip karštis ir masė juda vertikalia fasado ertme. Skyrėsi šių fasadų ertmės plotis. Abu fasadai buvo 24 m aukščio, tačiau skyrėsi gaisro patalpos aukštis. Buvo palygintas vertikalusis temperatūros pasiskirstymas dvigubo fasado ertmėje.

scholarly journals Spread of smoke and heat along narrow air cavity in double-skin façade fires

2014 ◽  
Vol 18 (suppl.2) ◽  
pp. 405-416 ◽  
Author(s):  
Lun Chow
Keyword(s):  
Air Temperature ◽  
Vertical Channel ◽  
Cavity Depth ◽  
Glass Pane ◽  
Air Cavity ◽  
One Dimensional ◽  
Hot Gas ◽  
Heat Transfer Theory ◽  
Smoke Spread ◽  
Double Skin

A scenario on double-skin fa?ade fire was identified earlier for hazard assessment. A flashover room fire occurred next to the fa?ade, broke the interior glass pane and spread to the fa?ade cavity. As observed in experiments, hot gas moved up as a vertical channel flow for narrow fa?ade cavity. Heat and smoke spread along the narrow air cavity of a double-skin fa?ade will be studied in this paper. A simple mathematical model is developed from basic heat transfer theory for studying the vertical air temperature profiles of the hot gas flowing along the cavity. Assuming one-dimensional flow for hot gas moving up the fa?ade cavity, conservation equations on mass and enthalpy were solved. Experimental results on two double-skin fa?ade rigs of height 6 m and 15 m with narrow cavity depth were used to justify the results. A total of 11 tests were carried out. Correlation expressions between cavity air temperature and the height above ceiling of the fire room were derived.

scholarly journals The impact of sustainability on fire safety

2021 ◽  
Author(s):  
◽  
Mohammad Musa Al-Janabi
Keyword(s):  
Fire Safety ◽  
Sensitivity Study ◽  
Mitigation Measures ◽  
Fire Dynamics ◽  
Fire Event ◽  
Use Of Resources ◽  
Smoke Spread ◽  
Double Skin ◽  
The Impact ◽  
Small Models

<p>There is a growing demand for building green buildings that are perceived to have benefits environmentally through promoting recycling, energy efficiency and efficient use of resources. The green movement has also led to innovative technologies that are focused on reducing cost. However, the fire safety industry has concerns with the use of certain technologies that create passages for smoke and fire to spread such as passive ventilation or materials that can burn severely and release large amount of toxins. The benefit of this research is to determine which features are high risk and are commonly used. The aim of this research is to investigate whether sustainable or green features have an influence on fire safety in commercial buildings and determine which feature or features would have the most significant implications for building safety in regards to tenability. A detailed investigation was done on passive ventilation such as double skin facade and the thesis also briefly discusses other green features and their implications. There were two methods used to collect data. The first was a qualitative study done through sending out surveys to fire engineers to rate and rank the most significant features that have negative implications for fire safety in reference to the New Zealand Building Code Fire Safety Section criteria and objectives. Then, a one hour interview was carried out to determine the reason behind the engineers’ choice and their perceptions. The results from the surveys and the interviews were that double skin facade and atrium were ranked the most significant. The surveys established double skin facade has the highest ranking in terms of the worst feature, and the fire engineers reinforced that double skin facade needs to be studied as there is not enough research that have gone into this feature. While atrium issues are known and mitigation measures are well developed. A subsequent analysis for only double skin facade is conducted using Fire Dynamics Simulator (FDS) because little literature is found in regards to fire safety and double skin facade. FDS was used to simulate 14 small models and 2 large models for the best and worst scenarios of DSF. Each of the 14 models, one to three parameters are changed as part of the sensitivity study to determine which parameter have the most and least effect on fire safety in term of Carbon Monoxide (CO) and visibility. The issues the engineers raised and the mitigation measures were modelled, because the engineers had stated their opinions not facts. The output results from FDS illustrated that it is essential that the system shuts off in a fire event to prevent smoke spread to upper floors, which is the same mitigation measure that were emphasised at the interviews.</p>

Numerical Simulations on Airflow to the Double-Skin Fac¸ade Cavity by an Adjacent Room Fire

2010 ◽  
Author(s):  
C. L. Chow
Keyword(s):  
Fire Hazard ◽  
Flame Spreading ◽  
Building Model ◽  
Architectural Feature ◽  
Adjacent Room ◽  
Double Skin ◽  
Computational Fluid Dynamics Cfd ◽  
Three Stages ◽  
In Fire ◽  
Level Building

The architectural feature of double-skin fac¸ades has been proposed in green or sustainable buildings. However, there are potential fire risks and so the design was normally not accepted by the authorities having jurisdictions. The scenario of trapping heat and smoke in the fac¸ade cavity is identified as hazardous and should be better understood. Hot smoke flowing out of openings driven by an adjacent room fire to the double-skin fac¸ade cavity was simulated using computational fluid dynamics (CFD). A five-level building model was taken as an example. A fire occurred in a room at the third level under two different heat release rates of 1 MW and 5 MW, and cavity depths of 0.5 m, 1 m and 2 m were considered. Based on the simulation results, three stages of flame spreading from the room fire to the adjacent fac¸ade cavity were proposed in fire hazard assessment for this architectural feature. Results suggested that wider cavity depths would be more dangerous, having a greater chance to break the adjacent upper interior glass panes. Smoke or even flames can then spread to the upper levels.

scholarly journals Numerical Studies on Effects of Cavity Width on Smoke Spread in Double-skin Facade

2012 ◽  
Vol 45 ◽  
pp. 695-699 ◽  
Author(s):  
Junmei Li ◽  
Xuefei Xing ◽  
Cheng Hu ◽  
Yanfeng Li ◽  
Chenchen Yin ◽  
...  
Keyword(s):  
Numerical Studies ◽  
Smoke Spread ◽  
Double Skin ◽  
Cavity Width

scholarly journals NUMERICAL STUDIES ON SMOKE SPREAD IN THE CAVITY OF A DOUBLE-SKIN FAÇADE

2015 ◽  
Vol 22 (4) ◽  
pp. 470-479 ◽  
Author(s):  
Jie JI ◽  
Yi Fan LI ◽  
Wen Xi SHI ◽  
Jin Hua SUN
Keyword(s):  
Heat Release ◽  
Tilt Angle ◽  
Key Factors ◽  
Release Rates ◽  
Turbulent Vortex ◽  
High Rise ◽  
High Rise Building ◽  
Numerical Studies ◽  
Smoke Spread ◽  
Double Skin

In this paper, influence of two key factors, fire room height and outer pane tilt angle, on smoke spread in the cavity of a double-skin façade (DSF) was studied numerically. The fire room was located adjacent to the DSF on the 2nd, 4th and 6th floors, respectively. The outer pane tilt angle varied at 80°, 90° and 100°. All cases were under two fire heat release rates of 1 MW and 5 MW. Results suggested that fire room height and outer pane tilt angle had significant effects on smoke spread in the cavity. For different fire room heights, there were two markedly different scenarios of smoke spread in the cavity between two vertical panes in a high-rise building. For outer pane tilt angle, the DSF with an inward tilted or vertical outer pane was dangerous for the upper floors due to hot smoke adhering to the upper inner pane. However, the turbulent vortex in the DSF with an outward tilted outer pane prevented hot smoke flowing out from the fire room.

scholarly journals The impact of sustainability on fire safety

2021 ◽  
Author(s):  
◽  
Mohammad Musa Al-Janabi
Keyword(s):  
Fire Safety ◽  
Sensitivity Study ◽  
Mitigation Measures ◽  
Fire Dynamics ◽  
Fire Event ◽  
Use Of Resources ◽  
Smoke Spread ◽  
Double Skin ◽  
The Impact ◽  
Small Models

<p>There is a growing demand for building green buildings that are perceived to have benefits environmentally through promoting recycling, energy efficiency and efficient use of resources. The green movement has also led to innovative technologies that are focused on reducing cost. However, the fire safety industry has concerns with the use of certain technologies that create passages for smoke and fire to spread such as passive ventilation or materials that can burn severely and release large amount of toxins. The benefit of this research is to determine which features are high risk and are commonly used. The aim of this research is to investigate whether sustainable or green features have an influence on fire safety in commercial buildings and determine which feature or features would have the most significant implications for building safety in regards to tenability. A detailed investigation was done on passive ventilation such as double skin facade and the thesis also briefly discusses other green features and their implications. There were two methods used to collect data. The first was a qualitative study done through sending out surveys to fire engineers to rate and rank the most significant features that have negative implications for fire safety in reference to the New Zealand Building Code Fire Safety Section criteria and objectives. Then, a one hour interview was carried out to determine the reason behind the engineers’ choice and their perceptions. The results from the surveys and the interviews were that double skin facade and atrium were ranked the most significant. The surveys established double skin facade has the highest ranking in terms of the worst feature, and the fire engineers reinforced that double skin facade needs to be studied as there is not enough research that have gone into this feature. While atrium issues are known and mitigation measures are well developed. A subsequent analysis for only double skin facade is conducted using Fire Dynamics Simulator (FDS) because little literature is found in regards to fire safety and double skin facade. FDS was used to simulate 14 small models and 2 large models for the best and worst scenarios of DSF. Each of the 14 models, one to three parameters are changed as part of the sensitivity study to determine which parameter have the most and least effect on fire safety in term of Carbon Monoxide (CO) and visibility. The issues the engineers raised and the mitigation measures were modelled, because the engineers had stated their opinions not facts. The output results from FDS illustrated that it is essential that the system shuts off in a fire event to prevent smoke spread to upper floors, which is the same mitigation measure that were emphasised at the interviews.</p>

scholarly journals Computational modeling of fire safety in metro-stations

2021 ◽  
Author(s):  
Philip McKeen
Keyword(s):  
Fire Safety ◽  
Performance Based Design ◽  
Cfd Model ◽  
Fire Dynamics ◽  
Evacuation Modeling ◽  
Fire Dynamics Simulator ◽  
Cfd Models ◽  
Smoke Spread ◽  
Modeling Software ◽  
Computational Fluid Dynamics Cfd

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).

scholarly journals MODELING OF PROCESSES OF OCCURRENCE AND SPREAD OF FIRES IN GRASS ECOSYSTEMS

Fire Safety ◽  
2020 ◽  
Vol 36 ◽  
pp. 44-48
Author(s):  
A. Kuzyk ◽  
V. Tovaryanskyi ◽  
K. Drach
Keyword(s):  
Wind Speed ◽  
Forest Fires ◽  
Fire Hazard ◽  
Human Life ◽  
Grass Cover ◽  
Combustible Material ◽  
Fire Dynamics ◽  
Widespread Species ◽  
Entire Area ◽  
Fire Front

Formulation of the problem. Fires in natural ecosystems are emergency that leads to a violation of the balance of the environment and human life. Along with forest fires, the consequences of which are significant material damage and a detrimental effect on the atmosphere, grass fires occur, which entail the destruction of phytocenoses and representatives of the animal world. Prevention of grass fires is an urgent task that requires research in this direction. The purpose of the work is to assess the fire hazard in areas dominated by creeping pyrium (Elytrigia repens) as a representative of the widespread species of grass vegetation in meadows, pastures, agricultural areas that are not exploited, etc., under meteorological conditions favorable for the spread of fires, and the humidity of combustible material, as well as the geometric parameters of plants. Description of the material. A study of the fire hazard of areas covered by grassy vegetation from the average grass height and wind speed using computer simulation of a grass fire in the environment of the Wildland-Urban Fire Dynamics Simulator (WFDS) physical model was carried out. The fire hazard was estimated for creeping wheatgrass with an average plant height of 20, 40, 60, 80 and 100 cm from the propagation speed of the fire front, taking into account wind speeds of 0, 1, 2, 3, 4, 6, 8 m/s. Cases are noted in which, under the influence of weather conditions, ignition did not occur, but only ignition of combustible material was observed without further spread of fire, as well as cases of occurrence and spread of burning over the entire area of grass cover. Results. Based on the simulation results, the values of the propagation rates of the fire front in grassy areas were obtained. The fire speed is greatest at a height of grass cover of 40 cm and a wind speed of 3 m/s, and the lowest at a height of grass cover of 60 cm and a wind speed of 0 m/s. A relationship is established that describes the dynamics of a fire along the height of the grass cover as a combustible material. Scientific novelty. It has been established that in terms of the speed of propagation of the fire front, the greatest fire hazard of the grassland of creeping grass is observed at an average grass height of 40 cm and a wind speed of 3 m/s, which is more than 5 times this figure compared to a grass height of 60 cm in the absence of wind.

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