2_什么是火灾风险评估.pptx

Chapter2 What is Fire Risk Assessment,Chapter2 火灾风险评估的基本概念,本章引入火灾风险评估的基本概念火灾风险评估－fire risk assessment　指对火灾－人们所不希望发生的这类事故的后果，带给人员和财产的风险的评估2.1 综述,Basic concepts of fire risk assessment will be introduced in this chapter.The term fire risk assessment refers to assessing risks to both people and property as a consequence of unwanted fires.,2.1 overview,In a simple risk assessment the probability of a certain unwanted fire scenario is considered and the consequence of that scenario are explored. In a comprehensive risk assessment all probable unwanted fire scenarios and their consequences are considered.,在简单的火灾风险评估过程中，仅对某些或某类火灾场景发生的可能性和结果进行分析和评估；在全面或综合的火灾风险评估过程中，对所有的可能火灾场景发生的可能性或结果进行分析和评估。

一个火灾场景(fire scenario )由一系列的火灾中的事件组成，这些火灾事件是推测可能在火灾过程中发生的事件，将某些防、灭火技术或管理措施的成功或失效/失败的过程连缀起来，就能够形成一个火灾场景因此一个火灾场景发生的可能性(probability)决定于这一系列事件中每一个防、灭火技术或管理措施的成功或失效/失败的可能性A fire scenario involves the projection of a set of fire events, all of which are linked together by whether the fire protection measures succeed or fail. The probability of a fire scenario is dependent on the individual probabilities of success or failure of fire protection measures.,对人员的风险(risk)既决定于能够对人员产生损害(harm)的火灾场景发生的可能性，又决定于火灾场景或者说火灾场景产生的后果(consequence )对人员造成损害的程度或水平(level of harm )。

通常应用火势增长、烟气传播、人员疏散、建筑结构响应和消防人员灭火效能等模型来对火灾场景的结果进行计算和模拟这部分内容不是本课程的授课内容，将在《建筑防火性能化设计》课程中讲述；而在了解火灾各个过程和阶段基本特征的基础上，建立相应火灾场景，分析火灾场景发生的可能性，是本课程的主要内容The risk to the occupants depends not only on the probability of the fire scenario that can lead to harm to the occupants, but also the level of harm to the occupants as a result of the consequence of that scenario. The consequence of a fire scenario can be assessed by using time-dependent modeling of fire and smoke spread, occupant evacuation and fire department response.,2.2 What is Fire Risk Assessment?前面讲过，火灾风险评估是指对火灾－人们所不希望发生的这类事故的后果，带给人员和财产的风险(risk)的评估。

它所应用到的基本原理与其他领域风险评估的原理是一致的2.2 火灾风险评估(Fire Risk Assessment)的基本概念Fire risk assessment is the assessment of the risks to the people and property as a result of unwanted fires. It employs the same basic principles of risk assessment that are used in many other fields. A simple risk assessment considers the probability of the occurrence of a certain unwanted fire scenario and the consequence of that scenario.,A comprehensive risk assessment considers all probable unwanted fire scenarios and their consequences. The definition of fire scenario will be discussed in the next section. It involves the linking of anticipated fire events by the success or failure of certain fire protection measures.,例如，评估建筑中的某一个火灾场景的后果对人生命造成的风险，这个预计的生命风险可由(2.1)式来表达：式中P是这个特定的火灾场景发生的可能性(频次或概率，rate或probability );C 是这个特定火灾场景造成后果预计导致的死亡人数。

2.1),Consider, as an example, the assessment of the expected risk to life to the occupants in a building as a result of one single fire scenario. The expected risk to life can be expressed by the following equation:where P is the probability of a certain fire scenario and C is the expected number of deaths as a consequence of that fire scenario.,(2.1),If the probability of a certain fire scenario occurring in a building is once every 20 years, then P = 0.05 fires per year. If the consequence of that fire scenario is two deaths, then C = 2 deaths per fire. From Equation 2.1, the expected risk to life as a result of that fire scenario is equal to 0.1 deaths per year, or 1 death every 10 years.,比如建筑中某一火灾场景发生的可能是２０年一次，则：P = 0.05 fires per year如果这个火灾场景的后果是死亡２人，则C = 2 deaths per fire从式(2.1)可知，这个火灾场景的预计生命风险为the expected risk to life ＝0.1 deaths per year或都 1 death every 10 years.每年0.1人死亡或每10年死亡１人。

当然在建筑中发生火灾的方式不止一种，那么对人员的风险通常要基于所有可能的火灾场景来进行评估那么一个全面的（comprehensive fire risk assessment ）风险可由(2.2)式来表达：式中的∑代表了对所有可能的火灾场景进行求和Pi 是某一个火灾场景 i 发生的可能性;Ci火灾场景 i 的后果造成的预计死亡人数 2.2),Because fires can occur in a building in more ways than one, the risk to the occupants is usually assessed based on all probable fire scenarios.A comprehensive fire risk assessment can be expressed by the following equation:,(2.2),要注意的是，火灾风险评估不仅包括对人员生命风险的评估，还可能包括对财产损失、对经营或生产的影响等造成损失的评估此时方程(2.1)和方程(2.2)中的后果也相应地更换为财产损失的后果It should be noted that fire risk assessments involve more than the assessment of the risk to life. It involves also the assessment of the loss of property, loss of business and so on, as a result of fires. Equations similar to Equation 2.1 and 2.2 can also be expressed for the other losses.,2.2.1 Fire ScenariosA fire scenario is a sequential set of fire events that are linked together by the success or failure of certain fire protection measures. A fire event is an occurrence that is related to fire initiation, or fire growth, or smoke spread, or occupant evacuation, or fire department response.,2.2.1 火灾场景-Fire Scenarios一个火灾场景由一系列火灾中连续发生的事件组成，通过把某些特定的防、灭火技术或管理措施成功或失败/失效的结果连缀起来而得到。

火灾中的一个事件－A fire event 　是火灾中发生的，与起火、火灾增长、烟气传播、建筑物结构响应、人员疏散或消防人员响应相关的事件，如果不是在火灾中发生的，或与火灾的上述过程无关的事件，则不视为火灾中的一个事件比如，火灾中发生的声、光报警是一个火灾事件；火灾中发生的断电或停水也是火灾不同的两个事件；而没有发生火灾时的停水，就不是一个火灾事件了。