Smoke Control System Research Articles

Impact of Technical, Human, and Organizational Risks on Reliability of Fire Safety Systems in High-Rise Residential Buildings—Applications of an Integrated Probabilistic Risk Assessment Model

The current paper presents an application of an alternative probabilistic risk assessment methodology that incorporates technical, human, and organizational risks (T-H-O-Risk) using Bayesian network (BN) and system dynamics (SD) modelling. Seven case studies demonstrate the application of this holistic approach to the designs of high-rise residential buildings. An incremental risk approach allows for quantification of the impact of human and organizational errors (HOEs) on different fire safety systems. The active systems considered are sprinklers, building occupant warning systems, smoke detectors, and smoke control systems. The paper presents detailed results from T-H-O-Risk modelling for HOEs and risk variations over time utilizing the SD modelling to compare risk acceptance in the seven case studies located in Australia, New Zealand, Hong Kong, Singapore, and UK. Results indicate that HOEs impact risks in active systems up to ~33%. Large variations are observed in the reliability of active systems due to HOEs over time. SD results indicate that a small behavioral change in ’risk perception’ of a building management team can lead to a very large risk to life variations over time through the self-reinforcing feedback loops. The quantification of difference in expected risk to life due to technical, human, and organizational risks for seven buildings for each of 16 trial designs is a novel aspect of this study. The research is an important contribution to the development of the next generation building codes and risk assessment methods.

Visualization study on the effect of ambient wind on smoke layer height in chamber fires under natural smoke exhaust condition

Ambient wind often affects the smoke movement and natural smoke exhaust performance in enclosure fires. In this study, six wind speeds and twelve kinds of vent combinations are designed. 72 groups of experiments are conducted to investigate the coupling effects of vent combination and ambient wind speed during quasi-steady state of natural smoke extraction in chamber fires. Compared to the traditional Particle Image Velocimetry (PIV) method, a novel particle image flow field visualization (PIFFV) technique is proposed, and a smoke recognition algorithm for the determination of smoke layer height is developed based on two-dimensional OTSU method. Experimental results show that using the PIFFV method and the proposed algorithm, smoke layer height can be determined more accurately, in comparison to the N-percentage method. When the height of outlet is higher than that of inlet, the worst smoke control effect is found. When the air inlet is located on the windward side, the effect of natural smoke extraction is better under a reasonable wind speed than that in a windless condition. However, when the height of outlet is lower than that of the windward inlet, the optimal smoke control effect is achieved without ambient wind. In addition, when the inlet is arranged on the sideward side, ambient wind has a limited influence on smoke layer height with a lower outlet. Results of this study can provide references for the design of smoke control and ventilation system in room fires.

Proposal of Air Supply Smoke Control System about Stair-case Considering Stack Effect & Opening of the Outside Door

Most of the special escape staircase smoke control systems for high-rise buildings in accordance with the national fire safety code NFSC 501A are constructed with smoke control only vestibule, making it difficult to expect a proper role in an emergency. This standard, which was created by introducing the concept of air supply pressurized smoke control 25 years ago, created Korea´s smoke control only vestibule, which was not found in developed countries, and has been mainly applied to it to fit into the poor architectural environment of the time. However, there is a fundamental flaw there, so the performance test for completion without occupants is passed, but in the presence of occupants, the performance does not come out properly and it is being blamed for being useless. In this regard, the author proposes a method of air supply pressurized smoke control for stair-case that avoid the smoke control method only vestibule, reduces the stack effect with good cost-effectiveness, and considers opening the outside entrance door of the stair-case.

A Study on the Securing of Evacuation Stability of Complicated Accommodation Called Go-Si Won

This study investigates the process of securing the evacuation safety of the residents of Go-Si Won, which is known as the most dangerous commercial building structure. Thus, it aims to analyze the fire characteristics of the ignition room regarding effective fire escape means. To achieve the research objective, the fire simulation was conducted and analyzed under various conditions at the honeycomb-shaped Go-Si Won. Consequently, the simulation showed an increase in escape permit duration, which was 32 to 36 s longer when operating the smoke control and sprinkler systems than opening smoke windows. The evacuation time shortens as emergency exit stairs are added. The fire facilities are difficult to operate and maintain because of malfunction caused by the building’s deterioration. To enhance the evacuation safety of the honeycomb-shaped Go-Si Won, institutional improvements are needed to strengthen the issuance criteria for facility safety completion certificates, depending on the number of implemented evacuation steps.

High rise buildings stairwells pressure differential systems tests and improvement solutions

The task of fire pressure differential systems in a building is to prevent smoke from entering protected spaces such as stairwells and areas that should remain smoke-free in the event of fire. The required overpressure must consider leakage within the protected space. This article presents the results of testing to determine the impact of leakage of the protected space on the conditions for maintaining overpressure. The research was conducted in accordance with draft standard N161-prEN12101-6. The pressure distribution as a function of time was obtained for stairwells with different levels of leakage, using a constant flow aeration fan as well as systems with a variable airflow. Practical application: Designers of differential pressure smoke control systems are required to calculate aeration fan airflow volume. The leakage level of protected spaces should be taken into consideration given that European Standard EN12101-6 suggests that gap areas should be minimal. Consequently, modern building design and construction requires estimation of the leakage area in such protected spaces. The objective is to improve safety of buildings and reduce the system reaction time during a fire.

Numerical and experimental study on the effects of a ceiling beam on the critical velocity of a tunnel fire based on virtual fire source

Ceiling beams, such as smoke screens, supporting beams, and ceiling pipelines, exist in several types of tunnels. The ceiling structure of a tunnel has a significant influence on smoke propagation. This study determines the critical velocity required to control fire smoke in a tunnel with a ceiling beam. We conducted model experiments and numerical simulations to analyze the effects of a ceiling beam on air flow structure and smoke propagation. An air re-circulation length model was fitted to determine whether a fire source lies within the vortex swirling zone. Using a virtual fire source, we obtained the critical velocity prediction model for a tunnel with a ceiling beam. The results indicate that the re-circulation length of the vortex swirling zone is determined by the beam height and tunnel height, but is independent of the longitudinal airflow speed. The form of the critical velocity model for a tunnel with a ceiling beam is consistent with that of conventional models, wherein the dimensionless critical velocity is proportional to the dimensionless heat release rate raised to the power of one-third. This implies that a virtual fire source can be used to determine the critical velocity. The proposed prediction model of the critical velocity for a tunnel with a ceiling beam is an improvement on previous models and can be used in the design of smoke control systems in tunnels with beams.

CFD Analysis of Smoke and Temperature Control System of Car Park Area with Jet Fans

Basements of hospitals are generally used as indoor parking area. When underground car parks are examined physically, it is not possible to ventilate them by natural roads. Therefore, in order to keep the density of harmful gases below certain limits; ventilation systems must be used. In this study, for a parking lot with a closed area of 19438.59 m²; jet fan system is designed and the performance of the system is simulated with Computational Fluid Dynamics (CFD). The covered parking area examined is located in Isparta; It is located on the 2nd basement of Isparta City Hospital. The parking area is divided into 5 zones and CFD smoke analysis is made for the jet fan ventilation system designed for the parking area. The purpose of this study in Isparta City Hospital (basement-2) to examine the ventilation system is designed for parking areas using CFD. The CFD analysis made allowed us to see the correct placement of the jet fans and to decide the best placement. In case of a fire, various scenarios were prepared in accordance with international standards and the best results were obtained.

The Cfd Analysis of Ventilation and Smoke Control System with Jet Fan in a Parking Garage

Basements of buildings are generally used as parking garages and vehicles located in there release harmful gases. It is generally not possible to ventilate parking garages with natural ventilation methods. For this reason, ventilation systems should be used to keep the concentration of harmful gases below certain limits. One of these ventilation systems is jet fan system. It can also be used for smoke control and exhaust of harmful gases in case of fire. In this study, the jet fan system was designed for a parking garage and its performance has been observed by Computational Fluid Dynamics (CFD). Carbon monoxide concentration and air velocity parameters were investigated according to the different car occupancy rates with the CFD analyses for daily ventilation. In the results, when the number of cars increased, the air velocities decreased in the areas where the cars located and exhaust of the CO gas took longer time. In fire analyses, the same parameters were analyzed according to the different jet fan hanging heights. In the fire ventilation results, when the jet fan hanging height was increased, distribution of the air velocity profiles changed and it took longer time to exhaust the CO gas from the car park.

Simulation of Fire in Super High-Rise Hospitals Using Fire Dynamics Simulator (FDS)

Background: Among various types of disasters, fire constitutes a significant threat to life and property in urban and rural areas. Protection the hospitals against fire is very important due to presence of disable persons, lack of awareness and expensive devices and equipments in the hospitals. The present study was aimed to fire simulation in the super high-rise hospital. Methods: This cross-sectional descriptive study was conducted in a super high-rise hospital (17 floor) in 2018-2019. The project was divided into two steps: 1) Preparation of 3D model of the hospital using 3D CAD Modeling Software; 2) The computational fluid dynamics (CFD) technique is used to predict the fire dynamics (smoke propagation, temperature distribution, heat release rate and total energy) in the hospital using the Fire Dynamic Simulator (FDS). Results: The fire simulation results showed that after 10 seconds from the onset of fire in the third floor of the hospital with the intensity of 1620/79 kW, the temperature, total energy and heat release rate reaches 87 °C, 5640 kW and 937 kW, respectively. According to the simulation results, after 600 seconds, the temperature, total energy and heat release rate were 610 °C, 928 kW and 933 kW, respectively, which the fire had reached to an uncontrollable stage. Conclusion: By correction of staircases and elevator shaft, the spread of fire can be controlled effectively. To improve the level of fire risk and appropriate actions during emergency situation in super high-rise hospital, required measures especially in the area of containment and extinguishment including buildings design for smoke control, fire alarm and extinguisher systems.

Numerical Investigation of External Wind Effect on Smoke Characteristics in a Stairwell

Fire-induced smoke is the most lethal threat to the residents in high-rise buildings and it is necessary to understand the smoke rising characteristics for the engineering applications of smoke control system. Previous researches only focused on smoke movement driven by buoyancy and stack effect. It is common, however, that external wind can flow inside the building through broken windows and affect the smoke flow. This paper studies the influence of external wind on smoke characteristics in a stairwell. A series of simulations were conducted in a full-scale staircase with top window open. The ambient wind velocity ranged from 0 m/s to 6 m/s and the heat release rate varied from 500 kW to 1500 kW. Results show that the rise time for plume reaching a given height increases with the wind velocity. For a HRR, smoke cannot overcome the wind force when wind velocity exceeds a critical value. Thus a quantitative model is proposed to predict the rise time of plume front considering the hindrance of wind. Moreover, the mass flow rate at the bottom door decreases with wind velocity due to pressure attenuation. However, the CO concentration increases by about 15% with wind velocity, which is a great danger to trapped victims.

Influence of natural smoke vent opening in stairway of multistorey building

Stairway used as an escape as well as firefighter’s route during evacuation. In addition, stairway connecting different floors of a building and becomes a path for the smoke spread in fire event. In a building, every escape route should be installed with smoke control system to ensure the prevention of dangerous smoke accumulation at those areas. The fire perimeter in terms of heat output and smoke generation is highly depends on building occupancy and the efficacy of smoke confinement may have a great challenge. In this paper, numerical simulations were conducted to study the efficacy of natural smoke vent to confine fire-induced smoke transportation in the stairways of multi-storeys buildings. The simulation used Fire Dynamic Simulator (FDS) was conducted on a full-scale building where the influences of smoke vent opening at different fire size were discussed. When the value of heat release rate (HRR) were kept constant, the different vent’s size opening had a different influence on the efficacy of smoke vent and an appropriate opening size was obtained and proposed for further action. The finding of this study can assist the fire engineer to ensure that the smoke vent installation play a good role in confinement of smoke diffusion.

Experimental Investigation of Effect of External Side Wind on Fire Behaviors in a Corridor Connected to a Shaft

High-rise buildings are usually in a windy environment. The motion of fire-induced smoke and fire behaviors may be strongly affected by the external wind forces except by the stack effect. It turns out that wind with different directions and velocities can cause disparity in fire dynamics. Since most previous researches only focused on the cross wind conditions, this work investigated the effect of external side wind from 0 m/s to 1.21 m/s on the air flow behaviors, combustion characteristics of methanol pools and smoke temperature in a 1/6 scaled corridor connected to a 6-floor shaft. A remarkable observation is that the external side wind (parallel to top window, shown in Fig. 1) leads to pressure attenuation inside building and induces air to flow inside through bottom door. Therefore, the smoke spreads faster under the synergic effects of side wind and stack effect. At the steady stage, the supplement air flow velocity increases with wind velocity but remains proportional to 1/3 power of HRR. An equation incorporating the wind effect is proposed to predict the air flow velocity. Results also show that compared to cross wind conditions, the mass loss rates of methanol pools increase at high wind velocities. The wind effect on smoke temperature is obvious in cases with small pools. Here, the temperature first increases to a peak value and then decreases with increased wind velocity. However, the temperature remains the same in cases with large pools within our wind velocity range. The temperature in the shaft is also correlated with mass loss rate and wind velocity. This work shows that external side wind would increase the fire hazard of buildings by contributing to the combustion and spreading of smoke. Thus engineers should consider the effect of side wind carefully when designing smoke control system.

A Comparative Study on Domestic and Foreign Standards for Air Supply for the Improvement of a Smoke Control System for High-Rise Buildings

한국의 경우 í™”ìž¬ì•ˆì „ê¸°ì¤€ì¸ NFSC501와 NFSC 501A에 따라 ì œì—°ì„¤ë¹„ 설계를 ì‹¤ì‹œí•˜ê³ ìžˆë‹¤. 하지만 기준상에 기재된 누설틈새 ë©´ì  ì‚°ì •ê¸°ì¤€ìœ¼ë¡œ 설계 및 시공 이후 ì œì—°ì„¤ë¹„ì˜ 성능을 ì¸¡ì •í•œ ê²°ê³¼ 설계 값과 맞지 않는 ë¬¸ì œì ì´ ë°œìƒí•˜ê³ ìžˆë‹¤. 이에 따라 한국, 일본, 영국 각각의 ì œì—°ì„¤ë¹„ 기준을 ë¹„êµí•˜ê³ ì´ì— 대한 계산을 실시하였다. 국내의 경우 NFPA501A와 해설서에서 ê·œì •ëœ 내용을 통해 ì¼ë¥ ì ì¸ 설계를 ì‹¤ì‹œí•˜ê³ ìžˆë‹¤. 하지만 국외의 경우 연기층 온도, 화재층 급기량, 덕트 손실율을 ê³ ë ¤í•˜ì—¬ 급기량 값이 한국보다 더 크게 도출되었다. 따라서 국내 ì‹¤ì •ì— 맞는 데이터가 구축되어야 í• ê²ƒìœ¼ë¡œ 판단된다.

A Study on Design Improvement for Smoke-Control System Using the Pressurization of the Elevator Shaft

A Study on Design Improvement for Smoke-Control System Using the Pressurization of the Elevator Shaft

Computational fluid dynamics-assisted smoke control system design for solving fire uncertainty in buildings

For every fire prevention design, ensuring safe evacuation and preventing the fire from spreading are primary considerations. However, actual fire scenarios inevitably involve many uncertainties, such as the fire source location, the heat release rate, the fire growth coefficient and so on, which make it difficult for the traditional fire prevention system to achieve these primary considerations. In this paper, an optimum and intelligent system design was developed using the feedback of real-time fire characteristics based on precise control logic using computational fluid dynamics. The new system can make an intelligent adjustment to adapt the real-time fire and to obtain the best smoke exhaust condition by coupling the smoke control system and a physical boundary. The fire uncertainties were used to validate the system design, based on a conventional composite building containing room, corridor and atrium. The results show that the intelligent system is capable of providing different and reasonable reactions for various fire scenarios and of ensuring the safe evacuation of the building. Some limitations of the system have been improved by incorporating a constraint factor into activation procedures for solving extra-large and ultra-fast fires. In general, this intelligent design proved useful as a smoke control system which could be implemented in many similar buildings.

Structure and Simulation of Roadway Disaster Simulation Control System for High Temperature Smoke Drill

In view of the outstanding problems of the training environment in the high-temperature smoke environment, such as failing to meet the actual combat requirements, poor effect and low efficiency, an integrated simulation exercise system of high-temperature smoke for coal mine emergency rescue is established, which mainly includes the high-temperature smoke control system and the smoke control system. The high temperature drill control system adopts PLC control temperature algorithm and introduces PID fuzzy control rule. The simulation results show that high accuracy of temperature and flue gas concentration can be achieved through PLC fuzzy PID control. The system can simulate the hot smoke environment and achieve the purpose of the actual exercise.

Internet of Things Based Electronic Toll Gate and Smoke Control System

In our regular day to day existence, explorers pay a guaranteed measure of assessment all the route through toll court to the administration. The national expressways and spans have toll doors, where individuals pay the charges for utilizing the interstates by remaining in the line, prompting superfluous break of venture. Subsequently, so as to decline this issue, this proposed framework approach for robotizing the installments of toll court by utilizing a Radio Frequency Identifier (RFID). In the proposed work, the client has an RFID label which has one unique identification number that empowers the RFID reader to examine the vehicle and it naturally distinguish the cash from the connected RFID account. As the smoke from vehicle exhaust discharge toxic carbon particles and causes smoke inward breath. So the dark carbon particles are expelled utilizing enacted carbon channel cushion and innocuous gas is discharged through the fumes in the vehicle.

Optimization of an automated smoke control system in an industrial atrium

Pool fires are the most common hazard in many industrial applications. Therefore, automated fire control systems and occupational safety design codes and procedures are of major importance in industrial building systems design. Smoke is the main factor that causes deaths and casualties in fires. Thus, fire safety engineering (FSE) considers smoke management system as one of the most important factors. In this study, smoke generation during pool fire is numerically simulated to optimize the smoke management system. The smoke and temperature distributions inside a mechanically ventilated atrium are simulated using a computational fluid dynamic (CFD) transient model after initiating a diesel pool fire in the worst case scenario. Four numerical models are simulated and their results are compared to choose the model that optimizes smoke control. The models enable better approximations of the underlying physical phenomena in smoke transport for a single phase gas mixture. A velocity field approach is predicted using a turbulent standard k-ε model to study the domain with smoke plume. The ability to demonstrate and predict the flow field inside the atrium while the roof exhaust fans are operating is also investigated. The study aids in smoke management systems' design and helps to better understand of smoke plume behavior inside large spaces.

Review and Validation of the Current Smoke Plume Entrainment Models for Large-Volume Buildings

The design of smoke management systems in large-volume enclosures is of utter importance for life safety, property protection, and business continuity in case of fire. Despite the recent international trend in smoke control design towards the use of advanced fire models, simple plume entrainment correlations are the basis of the discipline and are still a common practice since they are often incorporated in technical documents for the design of smoke control systems. Different plume entrainment correlations have been developed over the years and are cited in different national codes and design guides. These correlations have been widely investigated for fires in small enclosures, but their applicability and accuracy in large enclosures is not clear. The present work studies the suitability and applicability of these approaches to properly predict the fire induced conditions within large volumes. The results obtained from the plume entrainment correlations have been compared with full scale experimental data in an 8.000 m3 enclosure. Based on the results obtained by this analysis performed in a large-volume enclosure, the current methods available of modelling fire and determining the smoke produced by the fire might not be suitable. It was observed that for the steady state, the McCaffrey correlation gave results closest to the experiments, and for the transient evolution of the smoke layer, the Zukoski correlation. On the contrary, the popular Thomas method underpredicted smoke production and entrainment, giving the highest smoke layer interface heights and leading to estimations that are not conservative (with errors between 36.5% and 101%). The authors analyze the reasons for the discrepancies and give some practical recommendations for the design of smoke control in large volume buildings, such as that the use of such models to predict the smoke production of a given fire shall be only a first approximation and not a design tool, especially when using those models that have not shown a good match to the experimental data.

Numerical study on the effect of elevator movement on pressure difference between vestibule and living room in high-rise buildings

In this study, we experimentally and numerically investigated the effect of elevator movement on the pressure difference between vestibule and living room regulated by the smoke control system in a high-rise building. The elevator and smoke control systems using supplied pressure dampers are considered one of the most important systems for safe evacuation. However, the pressure field and flow rate are strongly disrupted by elevator movement. Thus, they can affect the performance of smoke control systems and hinder evacuation. The experimental results of this study are used to validate the results of the numerical study when elevator is moving at low speed or is stationary. Then, the effect of elevator movement on the pressure difference between the vestibule and living room, which is controlled by the smoke control system, is investigated numerically using ANSYS CFX. The elevator speed is increased from 10 to 70 m/s, corresponding to the real elevator speed increase of 1.5 to 10 m/s based on Reynolds similarity. It is found that the higher the elevator speed, the greater the pressure difference between the vestibule and living room. This shows that the airflow rate should be actively changed by considering the location of the elevator and its speed. The empirical correlation between elevator movement and pressure difference is derived.