Smoke Management Systems for Large Volume Space

Atria and other large volume space do not have the compartmentation that has traditionally been a major contributor of fire protection.The effectiveness of sprinklers in these large volume spaces is limited. For these reasons, smoke management systems for large volume spaces is of particular importance. Their primary goal is to maintain an enviroment in which the impact of smoke and heat on occupants is not life threatening. This involves keeping the height of the smoke layer above the highest level of occupancy for a defined period of time, longer than the expected time to evacuate the building. Three approaches to these systems are smoke filling , gravity smoke venting ,and smoke exhaust .This paper describes the design approaches to smoke management to achieve fire safety in atrium.     

Classification of Atria and Measures for Their Fire Protection

Due to imperfection of the present architecture fireproofing technique criterion for the fire protection of atrium, it can't satisfy the needs of practical project. On the basis of practical experience, by the way of analysis and synthesis, the forms of atrium are classified and the suitable measures of fire protection and smoke management system for atrium are suggested. The aim of this paper is to provide a scientific and perfect method for their design and auditing.     

Smoke Control Method in Atrium Building

This paper presents several regular smoke control methods in atrium buildings and analyses the factors that determine the smoke production rate of fire in atrium and balcony.As a result,eight designs of smoke control system are developed.     

Simulation of Evacuating Buffer in High-rise Building Fires

Buffer zone set between aisle and anteroom is proposed to improve the traditional mode of pressurizes mechanic smoke extraction. Fire Dynamic Simulation is used to simulate the model of high-rise fire. Eight models are set and analyzed, in which the smoke temperature distribution and concentration distribution are compared, and the best parameters is worked out. The result shows, when exhaust smoke volume is constant, the velocity of air curtain is as low as possible; when the volume of air curtain is constant, the smoke volume is as low as better. Based on the comparison, it is found that the smoke removal efficiency of mode 4 is the best one, which is about 74.06%. The evacuating buffer not only can let smoke out timely, but also can guarantee safe personnel evacuation.     

Numerical Simulation for Fire Smoke Flow in a High-rise Building with Patio Space

Characteristics of smoke flow and fire spread in a patio space of a high-rise building were studied to investigate their influences on fire compartment and safety evacuation.Fire development model was established and fire scenarios were designed to simulate fire and smoke spread by CFD software numerically based on concepts of fire performance-based design in a high-rise building with double patio space,whose height are 74.65 m and 55.95 m,respectively.Simulation results show that in all fire scenarios,performance targets for safety evacuation for people in each floor was satisfied,if smoke was extracted naturally using the patio space.Hang walls mounted in corridors around the patio space prevent smoke flowing out smoothly,shorten the coming of the risk time and increase fire danger.Using chimney effect,it is preferred to adopt natural smoke exhaust method in a high-rise building with patio space.     

Discussion on the Characteristics of Smoke Movement and Smoke Control Methods in a Shaft of High-Rise Building

Characteristics of smoke movement and smoke control in a shaft is a serious issue that closely related to the fire safety of high-rise building. This paper talks about the studies on the characteristics of smoke movement in a shaft of high-rise building from three aspects: the factors which influence smoke movement in a shaft, the distribution of smoke parameters and the upward velocity of smoke flow. Smoke control methods which are commonly used and the problems in engineering practice are summarized. Some methods thoughts are given to improve the efficiency of smoke control.     

Analysis of Fire Smoke Movement with Different Air Velocity at the Stair head to the Hall of a Metro Station

When a fire happens at the subway platform, the downward ventilation at the staircase which connects the hall and platform can prevent smoke spreading into the hall and provides guiding air for evacuation people. To investigate the influence of the ventilation rate on the smoke movement, the air velocity at the staircase was measured under three ventilation modes. Numerical model was established to simulate the real fire scenario. It is shown that the downward air velocity under fire is greater than that without fire, and the traditional design procedure without considering complex factors interaction in real fire scenario should be improved; when fire is near the staircase, smoke easily spills from the smoke screen to the concourse. And smoke concentration of concourse is even higher than that of platform because the hall is under air supply mode; when the fire locates at the public area of the platform, turning on the tunnel fans can increase the downside flow at the staircase. However exceeding high flow can produce disturbance and destroy the smoke stratification, so more area will be filled with smoke. Therefore, reasonable smoke management scheme is as important as smoke exhausting system capability.     

Thermal Radiation Effects on Smoke-flow in Atrium Fires

The field models for smoke flow in atrium, takings into account strong buoyancy, turbulence, radiation exchange and wall heat losses are developed according to the characteristics of the atrium fire. Realistic combustion processes in the burning fuel have not been included. A six-flux radiation model is included in a general mathematical model for fires, which are taking as a volumetric heat source, It is applied to the predictions of fire smoke development in a small-scale atrium. In order to avoid complicated radiation exchange models, radiation heat loss effects are combined to the wall heat loss. A General-purpose compute program PHOENICS has been developed to meet this need. Results of numerical calculations based on the field model are compared with test data for a fire in the small-scale atrium test facility. The resullts indicate that radiation transfer has the minor effects, due to the relatively low temperatures encountered. The method that the effect of radiation is included in the calculation of wall heat transfer losses by using maximum heat transfer coefficient is feasible. The field model used in the present study is not good enough, which a turbulent combustion sub-model must be included.     

Three-dimensional Large Eddy Simulation of Smoke Flow during Indoor Fire

Indoor fires are quite dangerous,claiming many casualties and resulting in great property loss.Using Computational Fluid Dynamics(CFD),a three-dimensional large eddy simulation model of smoke flow is set up.Through the simulation of smoke flow,the theoretical basis is provided for controlling a fire in multiple rooms,thereby saving people.The results of simulation show that high temperatures and thick smoke exist near the fire,and the probability of combusting other tinder will increase.Moreover,there are close relationships between fire and ventilation.The latter can lower the average temperature and speed up the spread of smoke flow and toxic gases,providing conditions for the further development of indoor fire.Moreover,from both the simulated calculation and physical measurement,it is shown that indoor fires and their temperature distribution and smoke concentration are influenced by the fire power and the room size.The results from calculation and measurement are quite consistent.     

A Study on Application of Air Pollution Diagnosis and Predict Model to Chongqing Urban

This paper presents results of a research project "The prediction of the Fire Smoke Flow Properties in the Building", supported by the National Natural Science Fund. The numerical model of fire smoke flow in the building and its applied computer software are outlined. The experimental results obtained from full-scale fire test are compared with the results of numerical prediction using computer software.     

Numerical Model of Hot Smoke Flow in Residential Fire

Based on the characteristics of spatial structure of residential units, the law of indoor hot smoke flow was investigated by experimental research on a platform model with multiple floors and rooms in a residential building. Three factors exerting influence on hot smoke flow in residential construction were mainly analyzed, including the relationship between the height of space and the area of single room, the size of doorway opening, and the hub space. Based on basic concepts of thermodynamics and fluid mechanics, the geometric relational model of the height of space and the area of single room impacted on filling speed of hot smoke in room was presented by conservation of mass. Moreover, under the influence of hot smoke flow, the formula of doorway opening size was developed by conservation of momentum. The results show that the fire safety of residential building should take full account of the impact of spatial structural. The indoor temperature distribution and hot smoke flow path will be controlled effectively by the design of single room size and room connectivity.     

Opening Flow Coefficient and its Effect on Fire Smoke Flow

The flow coefficient of the typical doors and windows in different states between opening and closing was tested in a high rise experimental fire tower. It can be used for the prediction calculation of the fire smoke flow and the calculation of the positive air supply as well as for the ventilation. Using the prediction software of the fire smoke flow properties in the building, the effect of the flow coefficient on the fire smoke flow was also studied.     

Experimental Analysis of Building Space Constructions on Hot smoke Flow in Residential Fire

Based on the characteristics of spatial structure of residential units, the effect of building space construction on temperature raise and hot smoke flow in residential fire was analyzed on building model with simulating multiple floors and rooms. The raise and distribution of temperature indoors were mainly tested under varied location of fire sources. And, the rule of smoke flow was discussed by using the law of temperature raise, indirectly. The results indicate that the mode of smoke flows is influenced by three spatial factors which include the form of junction terminal room construction; the height of down stand above the door and the relative locations of each room. The diffusion of hot smoke is prevented effectively by the down stand of the room; the temperature difference between indoor and outdoor should be higher than that of the room without down stand. When the open direction of door in non fire room is opposite to that of the door in fire room, there is much more hot smoke.     

Assessment and Suggestion on Management System of Vehicle Exhaust

This paper analyzes the deep reasons why the benefits are always poor though China has controlled the vehicle exhaust for more than ten years, as well as a successful experience of the developed countries. Contrasting the deficiencies of the previous Air Pollution Control Law and advantages of the present Air Pollution Control Law , the paper indicates the organization structure and management system of the EPA are not entirely eligible for the tasks though the new law entitles environmental administrations to strengthening the exhaust control. It calls for that, according to principle that a structure results in a function, China must establish the management system of vehicle emission control in metropolises as soon as possible. So we can implement this law and improve urban air quality that has deteriorated due to vehicle exhaust. This paper puts forward organization form, functions, tasks and effect of this system.     

烟雾剂熏蒸处理对采后猕猴桃生理代谢及贮藏效果的影响

猕猴桃采后预冷期间,采用两种防腐烟雾剂进行熏蒸处理后进行冷藏,研究比较烟雾剂熏蒸处理对采后猕猴桃生理代谢及贮藏效果的影响。结果表明,烟雾剂Ⅰ、烟雾剂Ⅱ及CK处理的猕猴桃整个贮藏期间果肉硬度、果实乙烯释放速度无显著差异;在贮藏15d及28d测定果实呼吸强度时,使用两种烟雾剂的果实呼吸强度显著大于对照果实,说明使用防腐烟雾剂后的28d内,果实的呼吸强度受到了刺激;腐烟雾剂Ⅰ处理果实的可溶性固形物含量显著高于CK果实;采用烟雾剂Ⅱ处理的猕猴桃果实,软化率和腐烂率都极显著低于对照果实。     

卷烟主流烟气中烟碱测量不确定度的评定

根据JJF(烟草)1—2007卷烟主流烟气中烟碱、焦油和一氧化碳测量不确定度评定指南,对卷烟主流烟气中烟碱的测量过程进行了研究,系统分析了整个测量结果的不确定度来源,表述出了合成标准不确定和扩展不确定度,为测定主流烟气中烟碱量提供了有效的、可靠的测量数据。     

Analysis of Yangtze River Water as a Potential Source for Developing a Water Source Heat Pump in Chongqing

Characteristics of smoke flow and fire spread in a patio space of a high-rise building were studied to investigate their influences on fire compartment and safety evacuation. Fire development model was established and fire scenarios were designed to simulate fire and smoke spread by CFD software numerically based on concepts of fire performance-based design in a high-rise building with double patio space, whose height are 74. 65 m and 55. 95 m, respectively. Simulation results show that in all fire scenarios, performance targets for safety evacuation for people in each floor was satisfied, if smoke was extracted naturally using the patio space. Hang walls mounted in corridors around the patio space prevent smoke flowing out smoothly, shorten the coming of the risk time and increase fire danger. Using chimney effect, it is preferred to adopt natural smoke exhaust method in a high rise building with patio space.     

抽吸条件对卷烟主流烟气pH和化学成分的影响研究

为了考察抽吸方式对卷烟主流烟气pH和化学成分的影响,以市售卷烟为试验材料,利用吸烟机研究深度抽吸条件下,卷烟烟气粒相物pH变化以及TPM、烟碱和CO释放量的差异。研究结果表明：提高抽吸频率、减少烟蒂长度、增加抽吸容量均能引起pH以及其他有害物质释放量的增加,但并不呈线性。某一抽吸参数的变化,对主流烟气气粒相物pH影响较小,而对烟碱释放量的影响较大。     

绿萝对香烟烟雾的净化与生理响应

为了研究室内观赏植物绿萝(Epipremnum aureum)对香烟烟雾的净化能力及其生长生理响应，从而为香烟烟雾污染防控提供依据，本研究模拟人的吸烟方式，在长、宽、高均为60 cm，密闭或间隔通风的玻璃装置中注入2支香烟，放置绿萝。监测72 h内CO和PM2.5浓度变化，观察植物的表型变化，测定植物叶片生理指标变化。结果表明，绿萝可有效吸收或吸附香烟烟雾产生的CO和PM2.5，净化空气；香烟烟雾处理对植物生长产生了一定的影响，叶片出现水渍状斑块，随时间延长，整叶发黄；植物叶片活性氧（超氧阴离子和过氧化氢）水平显著增加，造成膜脂过氧化加剧，其产物丙二醛含量显著增加；植物启动抗氧化酶系统及时清除活性氧；随胁迫时间延长，抗性减弱。通风可有效加速空气流动，减轻香烟烟雾对植物的伤害。因此，建议在吸烟区摆放绿萝并时常通风，可有效降低香烟烟雾污染带来的风险。     

Hybrid field network simulation of temperature in a building fire

A connecting platform between the field model and network model has been constructed, based on a multi functional building model. The field model is used to simulate the fire smoke in certain special compartments (the fire room and specific large space rooms), while the network model is used to simulate the uniform compartments. When combining the simulation results of the field model and network model as the interface boundary conditions for the each other, a hybrid field and network model is presented. The hybrid field network model can provide more detailed physical information of the fire smoke properties under a specific fire scenario for the specially confined compartments. In addition, the hybrid model can predict the fire smoke flow properties in the building accurately.