实际设计工作中遇到的防排烟问题的探讨

本文结合工作实际,对建筑防排烟设计中的一些问题进行了分析,包括封闭楼梯间和防烟楼梯间的设置;防烟楼梯间不设防烟设施的条件;防烟楼梯间、前室及合用前室的余压值;内走道排烟及其排烟面积的计算;机械排烟系统的补风;排烟口和排烟防火阀的形式等。同时依据各规范和手册的设计理论及其内涵,给出了相应的处理办法。     

加压送风系统设计中的几点问题

本文针对高层民用建筑加压送风系统设计中剪刀楼梯间共用加压送风竖井问题、加压送风系统中防火阀的设置问题、建筑的地上部分与地下部分共用防烟楼梯间的加压送风系统设计问题及只有一层地下室的防烟楼梯间等的加压送风量的确定问题,提出了几种具体的设计方案,供设计人员参考.     

防烟楼梯间及其前室正压送风系统的探讨

结合具体工程,探讨不具备自然排烟条件的防烟楼梯间、消防电梯间前室或合用前室采取机械加压送风的防烟措施,并探讨地上和地下部分在同一位置的防烟楼梯间、消防电梯间前室或合用前室设置机械加压送风时加压送风系统风道的设置及正压送风机的选择,指出地下和地上部分防烟楼梯间位于同一位置且合用同一送风道时采用常闭型送风口的优缺点。     

齐齐哈尔市新世纪广场工程消防设计难点分析

齐齐哈尔市新世纪广场采取商业营业厅部分与住宅部分核心筒以耐火极限大于3 h的实体墙进行分隔、设防火挑檐等防火措施,商业营业厅按裙房考虑防火分区面积,疏散宽度指标按《建筑设计防火规范》要求确定。高度不超过24 m的建筑空间内独立使用的楼梯间,因垂直疏散距离较短,可以采用封闭楼梯间;但若封闭楼梯间无可开启外窗,不能做到自然排烟和通风,则应按防烟楼梯间设计。     

防烟楼梯间加压送风的数值模拟

本文以某大楼防烟楼梯间及其前室作为计算实例,对防烟楼梯间的加压送风进行了数值模拟,结果显示楼梯间加压送风的均匀性不是非常重要,《高层民用建筑设计防火规范》的送风量能够满足楼梯间和前室的正压要求,同时为加压送风机的选型提供依据。     

机械加压送风系统中两种余压调节方式的讨论

随着现代建筑功能越来越复杂,高度越来越高,火灾危险性也越来越大,防火要求也越来越高,建筑防火最重要的任务是保证人员安全。而疏散楼梯间是保证人员安全撤离的最重要通道,《建筑设计防火规范》(2018年版) GB50016-2014中8.5. 1条规定"防烟楼梯间及其前室应设置防烟设施",《建筑防烟排烟系统技术标准》GB51251-2017中提出防烟楼梯间及其前室防烟设施可采用自然通风或机械加压送风系统。其中自然通风是利用设置在外墙的可开启自然通风窗快速的排出防烟楼梯间及前室内存在的烟气,以保证楼梯间及前室的疏散安全;而机械加压送风系统是通过向楼梯间及前室送入空气,使楼梯间及前室的压力大于走道,以防止其他区域的烟气进入楼梯间及前室。     

防烟楼梯间及前室和合用前室的防烟设计

对建筑内防烟楼梯间、消防电梯前室及合用前室防烟系统设计中遇到的一些问题进行了论述,依据相关规范,提出了对应的处理方法,并对高层建筑中防烟楼梯间及其前室(合用前室)的加压送风系统设计进行分析,以供参考。     

浅析楼梯设计要素

本文以建筑高度和建筑设计层数为主要线索展开,探索住宅建筑的封闭楼梯间、防烟楼梯间、电梯及楼梯构造设计。     

33F／34F住宅防烟系统设计若干问题的探讨

针对当前33F/34F住宅建筑防烟系统设计中的若干常见问题,阐述了自己的看法,认为地下室防烟楼梯间和地上防烟楼梯问加压送风系统应分别设置、分别控制.对于不同的建筑形式的防烟楼梯间进行了分析,提出了33F/34F住宅防烟系统分段设计的具体做法及注意事项.     

正压送风防烟系统在防烟楼梯间中风压与风量变化研究

研究了正压送风系统的送风量和风压在防烟楼梯间及前室门开启和关闭的变化,以及在实际应用中的主要问题,并提出相应的解决办法,以更好的发挥机械正压送风系统在防烟楼梯间内的防烟作用。     

The modelling of stairwell flows

This paper extends an earlier investigation of scale effects on buoyancy-driven recirculating flows in stairwells of the kind adopted in domestic accomodation. Further consideration is given to the role Reynolds number, which proves to have unexpected features, possibly because stairwell flows fall into the range of incipient instability. A technique is developed to introduce explicitly the fraction defining the way in which the energy loss from the system is divided between the regions above and below the stairway. Finally, it is shown that a single empirical constant suffices to complete relationships among key of the processes of heat and mass transfer. The resulting formulae are suitable for incorporation within computer models of energy balances for complete buildings.     

Buoyancy-driven flow through a stairwell

The present work concerns the measurement and the computational fluid dynamics (CFD) modeling of buoyancy-driven air flow through a stairwell that connects the two individual floors of a residential building. A series of experiments was performed in order to study the mass and heat transfer between the two floors. Air flow rates through this stairwell were measured using a single tracer gas decay technique. The analysis of results provided relations which can predict the mass and heat flow rate as a function of the interzone average temperature difference. These results were compared with values estimated by using validated CFD algorithms and showed very good agreement.     

Numerical simulation of fire-induced flow through a stairwell

Smoke movement and ambient airflow in a stairwell under fire scenarios are studied numerically using large eddy simulation. Numerical investigation is performed on a typical two-storey confined stairwell, with an open door on the top floor and a fire source on the ground floor. Results show the existence of fairly distinct layers of hot smoke and ambient air under different fire scenarios. It is found that heat release rate has a remarkable effect on distributions of smoke temperature, velocity and oxygen concentration. This paper indicates that detailed patterns of velocity, temperature and species concentration and their evolutions can be predicted by numerical simulation of a stairwell during a fire.     

住宅楼梯间供暖温差修正系数测试分析

认为新修订的暖通规范中采用对楼梯间各层按相同的温差修正系数的计算方法会造成计算误差。通过对居住建筑楼梯间温度场的实测，分析研究了这一问题，为设计计算提供了实测数据和推荐的计算方法。     

高层建筑楼梯间烟囱效应实测分析

以西安地区一实际高层建筑为例,研究了在热压和风压共同作用下自然通风对高层建筑楼梯间空气流动状况的影响,以及在热压单独作用下楼梯间的烟囱效应。通过对不同天气情况下楼梯间门洞风速和温度的实测,测出了烟囱效应现象并了解到了天气状况对楼梯间中和面的位置和楼梯间内空气流动方向的影响比较大。     

带消能楼梯间框架结构抗震性能分析

带消能楼梯间属于一种较为新颖的楼梯结构,其通过减震楼梯及阻尼墙的设置,可有效消除楼梯板的支撑效应,提高对结构的约束效应,进而控制楼梯间抗震性,面对自然灾害,使楼梯成为人们逃生的重要通道。故对带消能楼梯间建模,便于分析,以有限元模型为基础,模拟地震影响下的楼梯结构变化。最终分析发现,消能楼梯间可以对地震产生的能量间接消耗,进一步增加阻尼比,以此提高框架结构抗震性能,控制构件受到损坏的程度,具有推广意义。     

On stairwell and elevator shaft pressurization for smoke control in tall buildings

Elevator shaft and stairwell shaft-pressurization systems are studied as means of smoke migration prevention through the stack effect in tall buildings using the CONTAM simulation software. A thirty story building model is considered with exterior leakages calibrated to experimental data for both a residential and a commercial building. Stairwell pressurization is found to be completely feasible in the absence of elevator shaft pressurization. In contrast, coupled elevator shaft-pressurization systems are found to produce prohibitively large pressure differences across both the elevator and stairwell doors if (1) minimum pressure differences must be maintained at both open and closed elevator doors and (2) if the system must function properly when the ground floor exterior building doors are closed. Even in these cases situations arise in which smoke may enter the shaft and be actively distributed throughout the building by the fan system. These differences between stairwell and elevator shaft pressurization are directly attributable to the much larger leakage areas associated with elevator doors. Relatively large flow rates through the open elevator doors act to pressurize the ground floor of the building, indirectly causing large pressure differences across upper floor elevator doors. Furthermore, the results show that there is a strong coupling between the fan speed requirements of the stairwell and elevator shaft-pressurization systems. Fan requirements are also found to be sensitive to the ambient temperature. Effects of the fan location, louvers, vents, the building height, and the number of elevator cars and/or shafts are also addressed.     

敞开楼梯间消防安全措施的探讨

针对近几年来国内商场、市场火灾时因烟气通过敞开楼梯间蔓延，造成大量人员伤亡的问题，对不同情况进行分析，提出了三种解决火灾烟气通过敞开楼梯问向上部楼层蔓延的方法，并分析了各自的优缺点。     

加压送风时楼梯间内压力与空气流速的数值模拟

采用数值模拟的方法对不同火源位置和不同加压送风量下高层建筑楼梯间内加压送风的效果开展研究。结果表明,当加压送风机位于底部时,楼梯间内的正压值在着火楼层以下随高度的增加而降低,在着火楼层处达到最低,在着火楼层以上随高度的增加而增加并最终趋于一稳定值,该稳定值与加压送风量近似呈线性增长的关系。着火楼层开门处的空气流速较快,其他楼层的门缝流速相对较小。门缝隙处的空气流速随加压送风量的增大而增大,通过着火层开门流出空气的流速增加明显。     

Improvement of Positive Pressure Ventilation by optimizing stairwell door opening area

This technical note presents a strategy to increase the effectiveness of Positive Pressure Ventilation (PPV) tactics in firefighting. It is shown that deployment of a Door Open Area Reducer (DOAR) in an appropriate position, which increases the resistance to the air escaping the stairwell, can significantly improve effectiveness of PPV performance. The simulation results demonstrate that an optimal placement of the fan combined with an optimized DOAR height can increase the pressure significantly yielding higher PPV effectiveness.