Results from a cost-effective, decision-making model for building fire safety and protection

Presented in this paper are results obtained from the application of a cost-effective, decision-making system model that is used to appraise the level of fire safety and protection in office buildings. The effects of fire spread are calculated using two performance parameters; namely the fire-cost expectation and the expected risk to life. Designs in conformity with building code requirements and alternative building designs were considered.

Following consideration of various risk assessment procedures, it was decided to adopt a decision criterion which identifies alternative designs that are equivalent (in terms of expected risk to life) to code-specified designs, and which achieve such performance at a lower fire-cost expectation. On the basis of the decision criterion described herein, alternative designs were identified that are shown to be more cost-effective than designs in conformity with building codes. For the selected alternative designs, it was found that whilst both the fire-cost expectation and the capital cost of building construction are significantly lower, a similar level of life safety is maintained for occupants, compared with designs in conformity with building code requirements.

The system model can be used as a basis both to make immediate changes to current building code provisions, and for the introduction of a performance-based approach to design. In addition, the model can be used to identify those areas of research which have a major impact on the provision of cost-effective fire safety and protection provisions in buildings, and which accordingly are deserving of further investigation.     

Examining the Design of Escape Routes Using Performance-Based Criteria in a Case Study

Life safety in buildings is a primary concern of the society in all countries. Means of escape is one of the most important design aspects in building designs. Alternative means of escape is often required for any large room,where the maximum travel distance, the number of occupants, or the total floor area, exceeds the code prescribed limit. Whilst the definition of the alternative means of escape, and the purpose of providing alternative means of escape, are the same for all countries, the criterion to be satisfied as alternative means of escape varies from code to code. This paper examines the actual performance requirement for alternative means of escape, and proposes performance criteria to examine the alternative means of escape. Such an approach can be used in a performance-based fire safety design. This paper further examines situations where means of escape will exist only for a short time, after which the escape route will be affected by fire. A methodology is proposed,and examples are given to illustrate the use.     

Fire Hazard Assessment: Roadblock or Opportunity?

If a civil engineer designs a bridge, the basic requirement is that the bridge be safe. The designer must guarantee that the bridge will resist the traffic across it and weather conditions it will be exposed to. On the other hand, a fire protection engineer designing the interior of a building is not explicitly required to vouch for the building's fire safety. Though the authority having jurisdiction states that the interior finish materials, for example, must meet some requirements in terms of various fire properties, the authority leaves implicit a critical assumption: the expectation that using these materials will ensure fire safety—in other words, it will ensure that nobody would die should a fire break out in the building. This procedure for designing fire safe buildings has been in place for so long, it gives a significant level of comfort to all involved, and it implies minimum risk: the manufacturer knows exactly what is required and the authority having jurisdiction does not feel responsible for making any additional commitments of either time or money to make changes.Unfortunately, this practice has come to harm us over the years: new materials, products, or systems are being developed continually, some of which offer improvements, while others require compromises. Retaining the existing system can hurt the authority having jurisdiction in two ways: first, it may prevent the use of new designs, with overall better fire performance; and second, it may allow new designs to be assessed with inappropriate tools, so that they appear to be better than they are (examples of this type are too many to enumerate).Alternative designs may be approved today through a fire hazard assessment that may lead to a request for a code variance, called an equivalency. Regulations or specifications, including those by the authority having jurisdiction, may also require a fire hazard assessment to ensure fire safety in so-called fire performance-based code. Two other practical reasons why such fire hazard assessments might be undertaken are, first, if a manufacturer wants to develop an improved product and compare its fire performance with that of existing ones, and second, if a lawyer involved in product liability fire litigation requires a more technical basis to justify the use (or condemn the potential misuse) of a product involved in a fire incident where something went unfortunately wrong.There is understandable reluctance to follow the fire hazard assessment route because it may rock the boat. Manufacturers fear they may need to retest their materials or products, or that they may end up with increased product liability and, ultimately, lose market share. In addition, such assessments may call on the authorities having jurisdiction to develop technical reasons to accept or reject a design. However, proper fire hazard assessment should back up proven designs that have been shown, through long-term use, to be safe. Proper assessment should also ensure that adequate safety is maintained and business continues as usual. Finally, fire hazard assessment offers opportunities for entrepreneurship, innovation, and ingenuity, characteristics that drive our markets.     

哈尔滨西站东广场交通枢纽交通换乘厅消防设计研究

铁路站房交通枢纽汇集铁路、轨道交通、城市公共交通、社会交通等多种交通方式,为方便换乘,交通枢纽各空间需保持连通,其交通换乘空间防火分区面积及疏散距离一般超过规范要求,因此设计时往往会借助消防性能化的方法.本文以哈尔滨西站东广场交通枢纽交通换乘厅为研究对象,研究并阐述了其消防设计的流程及消防策略.     

Calculation of the heating rate of an unprotected steel member in a standard fire resistance test

ENV.1991-2-7 is the new ‘European standard code of practice for actions on structures exposed to fire’. The document recommends a standardized procedure for the calculation of the fire resistance of a structural member. For each member state of the EU, a national application document (NAD) is being drafted to provide values of those parameters used in the calculations described in the code of practice. The first part of this paper provides a justification o f the values recommended for test piece surface and furnace emissivities as well as the safety factors in the UK version of the NAD.

ENV.1991-2-7 is designed to have a working life of only three years, after which its contents will be reviewed in the light of the experience gained during its use, before being issued as a final EN standard. The second part of this paper attempts to identify the most important developments needed during this three year period. There is an urgent need to develop a reliable means of measuring and controlling the total heat flux incident on a specimen during a standard fire resistance test. The availability o f total heat flux control would allow modification of EN. 1363-1 (the standard fire resistance test) to achieve harmonization of fire test results across the whole EU.

A method has been developed by which existing fire resistance test data can be used to calculate the total heat flux incident on the specimen at any instant during the test. The method has been used to compare the total incident heat flux/time characteristics of beam testing. furnaces at the Warrington Fire Research Centre (WFRC) and TNO (Delft) as well as the column furnace at the Borehamwood laboratory of the Loss Prevention Council (LPC). These characteristics have then been compared with those implied in the draft UK-NAD for ENV.1991-2-7. The latter has been shown to use heat flux/time characteristics very similar to those derived from standard test data.     

COSMO—Software for designing smoke control systems in high-rise buildings

A differential computer model specifically designed to quantify smoke movement during a fire in a high-rise structure is described. The basic conservation equations are transformed into a computer code which can be used to determine the paths that smoke will take during a fire. The program is a tool for fire protection engineers to design a smoke management plan with the ultimate goal of improving occupant safety in the event of a fire. The computer code is based on a modified and improved differential smoke control model for the conditions in the floor spaces, stairwells and elevator shafts and it considers a complete set of variables that influence the motion of smoke throughout the building. Program output suggests ways to alter the pressure distribution within the building by using air handling equipment, so that occupants will have smoke-free areas on the floors and inside of the fire escape stairwells. Results for several example cases are provided, and the results are used to illustrate how smoke movement can be managed in order to mitigate dangerous conditions within the building.     

宾馆火灾逃生调查

通过对5起中小型宾馆火灾中的55名人员的逃生问卷调查，了解火灾现场及逃生人员的基本概况、火灾发生时人员所处的初始环境状态、火灾逃生行为反应及逃生途中的信息。研究表明，中小型宾馆类建筑在火灾时，服务人员和安全保卫人员能忠于职守，有效组织引导旅客疏散，是宾馆安全疏散的基本保障；疏散楼梯分隔使用，是造成火灾重大伤亡事故的主要原因；疏散标志失效，加重了火灾伤亡；疏散楼梯被封堵，加重了灾情。分析总结的火灾逃生经验，对于中小型宾馆类建筑逃生设计提供了可以借鉴的资料。     

A survey of the development of fire safety regulations for railways

After reviewing the historical background to fire safety on railways, the paper describes the reasons for a recent review of protective measures. Initially, the problem is outlined and some approaches to control briefly examined. Some basic factors aimed at improving the safety of passengers and operating staff are outlined. Methods of assessing hazards, and limitations of official regulations are considered in the light of a systems engineering analysis. Differences between types of passenger vehicle are mentioned, and the provision of escape methods considered. Freight trains are referred to briefly, as are locomotives and stations.     

Applying building information modeling to support fire safety management

Building information modeling (BIM) is useful in three-dimensional (3D) visualization and data/information storage for planning and maintaining building projects. Recently, researchers globally have been exploring the applications of BIM. In this work, a BIM-based model is designed to support fire safety management of buildings. The model comprises four modules — evacuation assessment, escape route planning, safety education, and equipment maintenance. The evacuation assessment module integrates BIM with a Fire Dynamics Simulator to calculate the required safety egress time and the available safety egress time to evaluate the ability to evacuate in case of fire. The escape route planning module utilizes BIM to determine whether the distance of an escape route is acceptable. The safety education module presents hazardous areas, videos of escape routes and directional maps, all in three dimensions, to educate the occupants of the building about fire safety. The equipment maintenance module is implemented in a web-based prototype to support maintenance tasks in a remote management manner. The results of applying BIM have demonstrated that BIM can effectively provide 3D geometric data to support the assessment and planning of fire safety (using the first three modules), and it can store information in support of safety management and property management in a web-based environment (using the equipment maintenance module).     

谈高层建筑消防安全疏散设计的优化

根据高层建筑消防安全疏散设计的原则,从延长危险来临时间、缩短疏散开始与逃生时间、建筑火灾疏散诱导系统设计等方面论述了高层建筑消防安全疏散设计的优化方案,以科学合理地设计高层建筑消防安全疏散设施。     

深圳前海地下道路人员逃生疏散研究

深圳市前海地下道路,具有地下立交、多点进出、变截面、长度特长等突出的结构特点,其火灾特性、疏散救援组织等更为复杂,因此需对地下道路逃生疏散结构设计的合理性进行研究。首先对地下道路疏散通道逃生出口通行能力、大型车辆人员疏散时间关键参数进行了现场实验研究,其次采用CFD软件模拟地下道路火灾烟气发展规律并确定可用安全疏散时间ASET,最后采用STEPS软件模拟地下道路人员疏散逃生所需安全疏散时间RSET。结果显示地下道路发生火灾时,人员基本8 min内可以疏散到无火灾隧道,但为保证人员均能在危险到来前安全疏散,应及时开启通风系统,以保证温度、CO浓度及可见度均在忍耐范围内。     

一种推拉式防火门

分析我国规范对推拉式防火门的限制,介绍其他国家的规范要求.介绍一种新型的推拉式防火门,能克服悬挂砝码、电动驱动方式的缺陷,采用机械方式驱动滑轮.钟摆式悬吊系统所需开启力较小,可防止受挤压时的滑轨变形,可靠性较高.减速制动装置可以避免失速造成夹伤人员.关闭时引拉装置将门扇推向边框,防烟性能强.该门占地少、避免门扇对楼梯内人员的二次伤害,适用于竖井分隔和有无障碍要求的场所.     

安全疏散性能化消防设计初探

对现行建筑有关防火规范要求进行分析，立足于保证人员安全，克服和解决当前执行中存在的问题。从建筑防火的基本原则出发，以探讨的方式提出性能化疏散设计的数学模型，并将有关建筑消防安全的各方面影响定义成该模型的函数，将建筑安全疏散设计的安全性评价从定性评价转化为定量评价。     

Dynamic modeling of fire spread in building

Modeling fire spread in a building is a key factor of a fire risk analysis used for fire safety designs of large buildings. In this paper, a dynamic model of fire spread considering fire spread in both horizontal and vertical directions is described. The algorithms for simulating the fire spread process in buildings and calculating dynamic probability of fire spread for each compartment at each time step of simulation are proposed. The formulae used in calculating the input data for the dynamic fire spread model are derived. The dynamic fire spread model can easily be applied for any building including high-rise buildings. A detailed example of calculation of fire spread in a two-storey office building is described.     

Fire safety aspects of PCM-enhanced gypsum plasterboards: An experimental and numerical investigation

New trends in building energy efficiency include thermal storage in building elements that can be achieved via the incorporation of Phase Change Materials (PCM). Gypsum plasterboards enhanced with micro-encapsulated paraffin-based PCM have recently become commercially available. This work aims to shed light on the fire safety aspects of using such innovative building materials, by means of an extensive experimental and numerical simulation study. The main thermo-physical properties and the fire behaviour of PCM-enhanced plasterboards are investigated, using a variety of methods (i.e. thermo-gravimetric analysis, differential scanning calorimetry, cone calorimeter, scanning electron microscopy). It is demonstrated that in the high temperature environment developing during a fire, the PCM paraffins evaporate and escape through the failed encapsulation shells and the gypsum plasterboard's porous structure, emerging in the fire region, where they ignite increasing the effective fire load. The experimental data are used to develop a numerical model that accurately describes the fire behaviour of PCM-enhanced gypsum plasterboards. The model is implemented in a Computational Fluid Dynamics (CFD) code and is validated against cone calorimeter test results. CFD simulations are used to demonstrate that the use of paraffin-based PCM-enhanced construction materials may, in case the micro-encapsulation shells fail, adversely affect the fire safety characteristics of a building.