Selection of Fire Detector in Atrium

The fuction and structure of the atrium are very complexity. If fire occurs,it will bring great loss. Forms of atrium and the characters of gas flow are analyzed, fire detectors are classified. Performance, applicability and the cause of wrong alarm of fire detector are compared comprehensively. According to the performance of detector, the shape of atrium and the character and possible danger of fire,a method of selecting fire detector to be applied to atrium is given. The validity of the method is explained clearly with an given example.     

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.     

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.     

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.     

The Core in Performance -Based Building Fire Protection Study and Its Development

The core of performance-based building fire protection design consists of the establishment of fire scenario,the enactment of fire and the simulation of fire and smoke-flow development.These are most important for performance-based building fire protection design.An unreasonable enactment or pre-digestion could result in a biggish error between the simulation outcome and the actual condition.In this paper,several emphases and some issues worth much attention are introduced and analyzed.In addition,a few important issues in simulating the fire and smoke-flow development related to Field Model are analyzed in detail.     

Setting of fire scenarios in performance based characteristic coefficient on the optimal quantity of concrete walls

China has no fire protection regualtion about the ancient buildings, and the research on this issue is limited in China.This paper proposes some very important issues in the setting of fire scenarios for ancient buildings, especially the spread of fire. It discusses the criterion and process of fire scenario setting. The integrity procedure of fire scenario setting includes the fire position set, the fire development curve set and the fire spread analysis. Two ways of the fire spread are proposed.     

Response Analysis of Speed Increase Gearbox System in Dynamic Excitation

Fire protection of steel construction is the main safety problem of steel structure buildings. Based on the theory on fire protection of steel structures, the measures for fire protection of steel construction in two ways were discussed-by construction design and by architectural technology.     

A SKETCH DISCUSSION ON SCIENTIFIC DICISION OF STRATGIC IMPORTANCE IN SAFBTY INVESTMBNT OF FIRE PROTECTION

This paper presents a problem of scientific decision of strategic importance insafety in vestment of fire protection and discusses the scientific con notation,far-sightnese,two-wayability,sychronism and effectiveness of the problem.On the basis of similar action principle of deter-minable multifactors,the main point,strentth and the suggestions of scientific manage system insatfety investiment of fire protection are advanced.     

Critical Temperature of Axially Restrained Steel Columns withPartial Fire Retardant Coating Damage

In order to investigate the fire resistance of steel columns with partial fire retardant coating damage in fire, based on the differential equation of equilibrium on each portion of steel column, the deflection of steel column after the fire retardant coating damage was derived, with the pined ends and rigid ends of the columns at elevated temperatures. The critical temperature calculation method was proposed for partial fire protection damage and axial restrained steel columns by taking the edge yielding criteria. The deflection and axial displacement were verified by finite element method at elevated temperature. With a case study, the critical temperature and relationship of axial force and temperature were obtained for pined column with axial restraint. It was shown that the axial force of the steel column at elevated temperatures was increased and the critical temperature was decreased by the axial restraint. The longer the fire retardant coating damage was and the higher the axial restraint was, the lower the critical temperature was.     

高温下钢管约束型钢混凝土柱的受力性能

火灾下无防火保护的结构构件温度会迅速上升,从而造成钢材和混凝土的强度明显下降。为了研究火灾下钢管约束型钢混凝土柱的受力性能,考虑火灾下钢管约束型钢混凝土柱的不均匀温度分布及温度对材料力学性能的影响,提出了火灾下受轴心荷载作用的钢管约束型钢混凝土柱承载力的计算方法。利用有限元软件ABAQUS对提出的计算方法进行了验证,结果吻合较好。进而采用该计算方法对影响高温下承载力的参数进行了分析,研究表明：随着构件截面尺寸的增加以及混凝土强度和钢材强度的提高,构件的承载力逐渐增加,而钢管壁厚的改变对承载力并无太大影响。利用有限元软件ABAQUS分析了荷载比、构件尺寸、钢管壁厚等因素对构件耐火极限的影响,发现耐火极限随着荷载比和钢管壁厚的增加而减小,随着构件尺寸的增加而增大。     

Current Situation and Prospects of Atrium Smoke Management Research

This paper surveys the current situation of atrium smoke management research at home and abroad. Recent research such as the types and configurations of atrium buildings, atrium smoke management system, smoke exhaust system modes and smoke exhaust effectiveness, atrium smoke filling process and its time constant, pre_stratification and detection, air flow for smoke control between the atrium and adjoining space, sprinkler effect are discussed. Regulations of atrium design and some problems in current national code (Code for Fire Protection Design of Tall Buildings GB50045-95) are also discussed and areas of further research are specified.     

Repression of the Interference in the Wigner Distribution and the Algorithm

Because the present Architecture Fireproofing Technique Criterion for Auto-Detection and Alarm Systems in Atria is one with faults, it can't satisfy the needs of practical use. According to the forms of atrium and the characters of gas flow, an Auto-Detection and Alarm System suitable for the atria is investigated. The aim of this paper is to discuss the perfect design method for the Auto-Detection and Alarm Systems in Atria.     

Computational Model and Influencing Factor Analysis of Reinforced Concrete Walls under Fire

The finite element software ABAQUS is used to calculate the deformation of reinforced concrete walls under fire. The calculated results agree well with previous experimental results. Based on the finite element model, the influences of such parameters as axial load level, lateral load level, height-to-thickness ratio, wall thickness, concrete compressive strength, steel reinforcement yield strength, steel reinforcement ratio and concrete protection thickness on deformation and fire resistance of walls are analyzed systematically. It is found that, under the conditions of big axial load level or wall thickness without lateral load and small height-to-thickness ratio, the reverse deflection of reinforced concrete walls in fire is apt to occur. Within the work range of parameters in common use, the fire resistance of walls decreases with the increase of axial load level, lateral load level, height-to-thickness ratio, steel reinforcement yield strength or steel reinforcement ratio, and increases with the increase of wall thickness or concrete compressive strength.     

PLANNING AND IMPLEMENTATION OF FIRE PROTECTION FOR HOSPITALS

This paper discusses the risk and features of conflagration in hospitals,the spec-ification and implementation of fire protection system,the measurement and test of fire-fightingsystem and evacuation against ernergency.     

Axial Force in Restrained RC Columns during Heating and Cooling Phases

Using the computer program of SAFIR, the influences of some parameters (i.e., axial/rotational restraint ratio, sectional dimension, load ratio, load eccentricity ratio, reinforcement ratio, and heating time, etc.) were analyzed on axial forces in restrained concrete columns exposed to ISO834 standard fire with cooling phase, compared with those in the standard fire without cooling phase.Based on the simulation results of 2880 cases, a practical calculation method for axial force in column was proposed.It was shown that: (a) for axially and rotationally restrained columns in fire with or without cooling phase, the enhancement coefficient of axial force increased gradually first, and then reduced gently or kept constant, and finally decreased quickly.However, in the late stage, the enhancement coefficient corresponding to fire without cooling phase dropped more significant than that with cooling phase; and (b) the influences of the rotational restraint ratio, column length and thickness of concrete cover on the enhancement coefficient of axial force in axially and rotationally restrained columns were limited subjected to fire with cooling phase, while the peak value of the enhancement coefficient increased with the increase of the axial restraint ratio, load eccentricity ratio and reinforcement ratio or with the decrease of the load ratio and sectional dimension.     

Study on the Energy Consumption of Atrium Buildings

This paper reviews the evolvement of the atrium. In this paper the function of atria in buildings and the thermal performance and climatic factors of atria were described. The factors influencing the energy consumption of atrium buildings were analyzed and some measures for energy saving were presented. By using a computer simulation, the impact of the atrium's physical parameters including atrium proportion, top-glazing area and atrium wall mass on its energy costs was studied.     

生物质气化供热在烟叶烘烤中的应用

摘要：为了实现烟叶烘烤的环保节能,进行了生物质气化设备的开发和试验.。结果表明：研制的生物质气化炉能确保烟叶烘烤的热量需求且能连续供热,烘烤的烟叶质量正常,热能利用率较高,能耗较低,中部烟叶公斤干烟耗燃料量为2.21-3.15kg,上部烟叶公斤干烟耗燃料量为1.76-1.93kg,与普通烤房的煤耗基本一致。生物质气化设备解决了秸秆气化炉连续大量供气、加料不熄火、电动出灰及火力大小控制等问题,但仍有不自动落料、焦油处理等问题尚待解决。     

Calculation of Constant Pressure Values for Relief Valves in the Fire Suppression Systems of High-Rise Buildings

The calculation of constant pressure values for relief valves in the fire suppression systems of high-rise buildings usually is based on the working pressure of pipe systems by experience.However,this method only is applied in the condition that the relief valves are installed on the effluent pipes of pumps.In order to confirm the proper constant pressure values of relief valves in fire suppression systems,a formula is deduced using hydraulics theory.The applications of the formula in fire suppression systems are also discussed.The constant pressure values for relief valves are directly related to three factors,namely,the flux and pressure of the fire pump,the located height of the relief valves,and the head loss of flux from the pump exit to the inlets of the relief valves.It is necessary to analyze the working condition of fire suppression systems and to be certain of the permissive pressure range for overpressure.     

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.