Influence of Fire Source Elevation on Positive Pressure Ventilation Effectiveness in Multi-Story Building Stairwells

This fire and life safety analysis was performed on the Grant M. Brown Engineering Building in order to determine if the building meets the life safety goals set forth by a prescriptive and performance based analysis. This building was built to a strict set of codes and standards. For the prescriptive analysis the buildings egress design, fire detection and alarm systems, fire sprinkler system, occupancy classification, construction type, and structural fire protection are evaluated in terms of the life safety of the occupants. In the performance based design analysis four computer based programs were used to model egress and fire simulated conditions. These models produced outputs that could be compared to tenability limits for the occupants to determine if the Available Safe Egress Time (ASET) was longer than the Required Safe Egress Time (RSET). In the first design fire scenario a sofa located off the main exit corridor ignites. At 240 seconds the tenability limit for visibility is reached, setting the Available Safe Egress Time (ASET). Full evacuation of the building is accomplished by 191.5 seconds, leaving a margin of 48.5 seconds before conditions become untenable. This building passed the performance based design criteria for maintaining tenability of the occupants during the complete egress of the building. In the second design fire scenario a set of office storage cabinets located under the main exit stairs on the east side ignites. At 180 seconds the tenability limit for visibility is reached, setting the Available Safe Egress Time (ASET). Full evacuation of the building is accomplished by 252.3 seconds. This evacuation time is more than the first scenario because the stairs become unusable in terms of visual tenability 60 seconds after the start of the fire and thus forcing the second story occupants to have to use only the remaining stairs on the west side of the building. The Available Safe Egress Time does not exceed the Required Safe Egress Time. This building fails the performance based design criteria for maintaining tenability of the occupants during the complete egress of the building. The end of this analysis makes recommendations on how to improve the buildings fire safety from the results found in the study.

ASET-A computer program for calculating available safe egress time

A sensitivity matrix method to understand the building fire egress performance gap

Time-dependent fire risk assessment for occupant evacuation in public assembly buildings

Large railway interchange stations with complex geometry are common in contemporary integrated railway networks. Fire evacuation is commonly designed using the timeline analysis in comparing Available Safe Egress Time (ASET) and Required Safe Egress Time (RSET) with agreed scenarios. Smoke management systems are required to achieve longer ASET. Egress time analysis will be evaluated in this paper for a typical large railway interchange. The fire environment was simulated using fire dynamics simulator (FDS), a software based on computational fluid dynamics (CFD). Design fires of 2, 2.5, 5, 10, 25 and 50 MW were used in estimating ASET. Egress simulations by the software SIMULEX were conducted to predict the RSET under passenger loadings of 0.5, 1, 2 and 4 m2/person. The results show that the ASET in most of the cases with higher fire size and with higher passenger loading are less than the RSET. Consequently, the passengers are unsafe in the event of fire evacuation. Therefore, a larger safety margin, defined as the difference between ASET and RSET, should be provided. In the case of low safety margin in some existing stations, fire safety management and procedures on handling fire incidents have to be reformulated properly and carefully.

A probabilistic ASET (Available Safe Egress Time)/RSET (Required Safe Egress Time) timeline assessment approach is presented to make uncertainty analysis on number of fatalities in building fires. ASET and RSET are achieved as two dependent random variables with consideration of uncertainties of fire dynamics and human behaviors. When analyzing stochastic ASET, uncertainty of design fires is considered by coupling Monte Carlo simulation with two-zone fire model. When analyzing stochastic RSET, uncertainty of fire detection and alarm time is considered by coupling fire model and Monte Carlo simulation. Occupant pre-movement time is proposed as probability distribution. The interdependency between ASET and RSET is considered in the analysis process by lognormal fire growth rates. To demonstrate the approach, a case study is discussed.

The evaluation of the available safe egress time (ASET) is essential for organizing people evacuation in case of fire in buildings or generic enclosures. Especially, the evacuation on the building structure equipped the sprinkler systems are essential nowadays because sprinkler systems are widely used and impact directly on the fire characteristics. Therefore, we performed a numerical study for finding out the effect of sprinkler systems on the ASET by Fire dynamic simulators (FDS). In this article, we conducted a numerical study of fire in a cinema equipped with automatic sprinkler systems. The fire was made from a chair and spreading rapidly to the others in the cinema. The study tested various sprinkler pressure: 0.5 bar, 1 bar, and 1.3 bar and different fire locations. ASET was considered life safety criteria based on Korea regulation: temperature and visibility. As a result, ASET estimated at least 120s and effected slightly by the pressure of sprinkler.

ABSTRACTA green railway station adopting natural ventilation was built in Hong Kong to promote sustainable architectural design. Similar to many other green or sustainable projects, such design failed to comply with the local fire safety codes. There are potential fire hazards due to the adopted green features. Better ventilation provision would supply more air to burn the combustibles in case of fire. Performance‐based design was applied using the timeline analysis to determine the fire safety provisions. In this paper, fire simulations were carried out to predict the available safe egress time (ASET) under low design fires with smoke toxicity including only the carbon monoxide concentration. Evacuation simulations were conducted to predict the required safe egress time (RSET) under low passenger loadings. Studies on human behaviour under big fires and heavy passenger loadings were not included. Problems to be encountered in this green railway station using the timeline analysis will be pointed out in this paper. ASET was estimated by computational fluid dynamics with bigger fires resulted from the green features. RSET was estimated by evacuation software under local passenger loadings. The results indicated that ASET are less than RSET under big fires with heavy passenger loadings. Copyright © 2013 John Wiley & Sons, Ltd.

A concept for estimating available safe egress time in fires

Understanding fire combustion characteristics and available safe egress time in underground metro trains: A simulation approach

When fire occurs in a large multiplex building, the direction of smoke and flames is often similar to that of the evacuation of building occupants. This causes evacuation bottlenecks in a specific compartment, especially when the occupant density is very high, which unfortunately often leads to many fatalities and injuries. Thus, the development of an egress model that can ensure the safe evacuation of occupants is required to minimize the number of casualties. In this study, the correlations between fire temperature with visibility and toxic gas concentration were investigated through a fire simulation on a multiplex building, from which databases for training of artificial neural networks (ANN) were created. Based on this, an ANN model that can predict the available safe egress time was developed, and it estimated the available safe egress time (ASET) very accurately. In addition, an egress model that can guide rapid and safe evacuation routes for occupants was proposed, and the rationality of the proposed model was verified in detail through an application example. The proposed model provided the optimal evacuation route with the longest margin of safety in consideration of both ASET and the movement time of occupants under fire.

A mathematical Model for estimating the time available for safe egress from a fire is formulated. The model simulates the conditions which develop during the course of an enclosure fire. Since life safety considerations are primary, the simulation model which is adopted focuses attention only on phenomena which develop between the times of fire ignition and onset of hazardous conditions. This allows significant simplifications in modeling which may not be otherwise justified. Using computed variables of a simulated fire scenario of interest, times of fire detection and onset of hazard which are deduced from realistic detection and hazard criteria would be estimated. The Available Safe Egress Time (ASET) would be defined as the length of the time interval which separates these two events. Quantitative specifications for a variety of detection and hazard criteria are identified. Results of exercising the model are presented, and ASET estimates are obtained for a wide variety of realistic fire scenarios. A comparison between experimental results of a multi‐room fire test and prediction of the single‐room model suggest that the model has potential utility in providing practical simulations of multi‐room fire environments.

최근 실내 공간에서의 재난, 화재와 테러 등 대피상황을 재현하여 이를 가시화하기 위한 연구가 주목 받고 있으며, 실내 공간에 대한 모델을 설계하고 인명 안전 평가를 통한 신뢰성 있는 분석이 요구되고 있다. 이에 본 연구에서는 실제적인 건물 화재 위험 요인을 고려하여 피난 안전성 분석과 피난 경로 안내가 가능한 시뮬레이션 모델을 개발하고자 하였다. 이를 위해 인천터미널역 역사를 대상으로 3차원 화재 및 피난 모델을 설계하고, 실내 내장재의 재질을 바탕으로 열 매개변수와 화재 인지 장치를 이용하여 화재 위험 분석을 수행하였다. 둘째, 인명안전을 위한 평가에 있어 화재 시뮬레이션인 FDS(Fire Dynamics Simulator)와 피난 시뮬레이션을 통해 재실자가 인체에 손상 없이 견딜 수 있는 피난허용시간(ASET: Available Safe Egress Time)을 산출하였다. 또한 화재를 감지하고 안전한 장소까지 완전하게 피난하는데 소요되는 피난요구시간(RSET: Required Safe Egress Time)을 계산하고 이를 비교 분석하였다. 결과적으로 연구대상의 3차원 공간적인 정보를 기반으로 한 실내 공간 모델과, 고시된 안전기준을 반영한 열차 내 화재 및 피난 위험도 측정 시뮬레이션 분석을 통해 보다 실제적인 안전성 평가를 수행 할 수 있었다. Recently, the research to visualize and to reproduce evacuation situations such as terrorism, the disaster and fire indoor space has been come into the spotlight and designing a model for interior space and reliable analysis through safety evaluation of the life is required. Therefore, this paper aims to develop simulation model which is able to suggest evacuation route guidance and safety analysis by considering the major risk factor of fire in actual building. First of all, we designed 3D-based fire and evacuation model at a subway station building in Incheon and performed fire risk analysis through thermal parameters on the basis of interior materials supplied by Incheon Transit Corporation. In order to evaluate safety of a life, ASET (Available Safe Egress Time), which is the time for occupants to endure without damage, and RSET (Required Safe Egress Time) are calculated through evacuation simulation by Fire Dynamics Simulator. Finally, we can come to the conclusion that a more realistic safety assessment is carried out through indoor space model based on 3-dimension building information and simulation analysis applied by safety guideline for measurement of fire and evacuation risk.

Urban large-scale complexes, such as shopping malls, pose significant challenges for fire safety management due to their intricate spatial layouts, high population density, and diverse occupancy characteristics. Efficient fire evacuation strategies are critical for minimizing casualties and economic losses; however, existing approaches often overlook the dynamic interplay between fire propagation and human behavior, resulting in suboptimal safety assessments. This study proposes an integrated simulation framework to optimize evacuation strategies by coupling fire dynamics with pedestrian flow modeling, aiming to enhance both evacuation efficiency and personnel safety. The methodology comprises three key steps: (1) Fire scenario simulation: A Building Information Modeling (BIM)-based digital platform is constructed to simulate fire propagation. Critical fire parameters (e.g., heat release rate, combustion model) are calibrated to quantify temporal variations in smoke temperature, CO concentration, and visibility across different zones. (2) Evacuation dynamics modeling: A pedestrian evacuation model is developed by integrating demographic factors (age structure, movement speed, population density) and fire-induced regional risks, enabling realistic simulation of crowd movement under fire conditions. (3) Safety performance evaluation and strategy optimization: Safety margins at staircases are assessed by comparing Required Safe Egress Time (RSET) and Available Safe Egress Time (ASET), followed by a safety grading system to identify high-risk bottlenecks. Evacuation strategies are then optimized to mitigate these risks. A case study was conducted on a shopping mall in Chengdu to validate the framework. Simulation results indicate an initial evacuation time of 260.4 seconds. Safety performance analysis revealed critical risks at staircases A and C (1st floor) and D (2nd floor) due to insufficient safety margins. After strategy optimization, the total evacuation time was reduced to 245.5 seconds, with safety margins at the three high-risk staircases increased by 130.8 s, 115.2 s, and 72 s, respectively, fully meeting safety requirements. The overall evacuation efficiency was significantly improved. This study demonstrates the effectiveness of the proposed framework in quantifying fire risks and optimizing evacuation strategies for large-scale complexes. The integrated simulation approach provides a scientific basis for evidence-based safety management and evacuation planning, offering valuable insights for urban fire safety engineering and emergency response optimization.

Urban large-scale complexes, such as shopping malls, pose significant challenges for fire safety management due to their intricate spatial layouts, high population density, and diverse occupancy characteristics. Efficient fire evacuation strategies are critical for minimizing casualties and economic losses; however, existing approaches often overlook the dynamic interplay between fire propagation and human behavior, resulting in suboptimal safety assessments. This study proposes an integrated simulation framework to optimize evacuation strategies by coupling fire dynamics with pedestrian flow modeling, aiming to enhance both evacuation efficiency and personnel safety. The methodology comprises three key steps: (1) Fire scenario simulation: A Building Information Modeling (BIM)-based digital platform is constructed to simulate fire propagation. Critical fire parameters (e.g., heat release rate, combustion model) are calibrated to quantify temporal variations in smoke temperature, CO concentration, and visibility across different zones. (2) Evacuation dynamics modeling: A pedestrian evacuation model is developed by integrating demographic factors (age structure, movement speed, population density) and fire-induced regional risks, enabling realistic simulation of crowd movement under fire conditions. (3) Safety performance evaluation and strategy optimization: Safety margins at staircases are assessed by comparing Required Safe Egress Time (RSET) and Available Safe Egress Time (ASET), followed by a safety grading system to identify high-risk bottlenecks. Evacuation strategies are then optimized to mitigate these risks. A case study was conducted on a shopping mall in Chengdu to validate the framework. Simulation results indicate an initial evacuation time of 260.4 seconds. Safety performance analysis revealed critical risks at staircases A and C (1st floor) and D (2nd floor) due to insufficient safety margins. After strategy optimization, the total evacuation time was reduced to 245.5 seconds, with safety margins at the three high-risk staircases increased by 130.8 s, 115.2 s, and 72 s, respectively, fully meeting safety requirements. The overall evacuation efficiency was significantly improved. This study demonstrates the effectiveness of the proposed framework in quantifying fire risks and optimizing evacuation strategies for large-scale complexes. The integrated simulation approach provides a scientific basis for evidence-based safety management and evacuation planning, offering valuable insights for urban fire safety engineering and emergency response optimization.