风险严重度指数法在毒气泄漏评价中的应用

Application of risk severity index in the assessment of toxic leakage accidents

为评价某区域或某设备潜在的毒气泄漏事故场景的风险水平,以对不同的风险等级进行风险控制和安全规划,详细介绍了工业事故风险评估方法ARAMIS所采用的风险严重度指数法。首先基于事故频率和后果的风险矩阵选取毒气泄漏事故场景;然后运用毒气当量浓度计算任意暴露时间下不同风险严重度等级所对应的特征距离,并根据同一风险等级内风险严重度指数与距离的线性关系计算任意点的风险严重度指数;最后应用1个实例分析了考虑所研究区域的风向概率后对风险严重度指数的真实影响,便于工厂或企业识别不同的风险等级,进行不同场景下风险水平的对比性研究,为其安全设计及风险分析提供了一种新的评估方法。

The paper is aimed to present a parameter developed in the context of methodology for identifying major accident hazards of European commission. The .suggested parameter, known as Risk Severity Index （S）, is expected to help to improve the evaluation of the risk level of the accident scenarios in a given plant. In doing so, first of all, the number of accident scenarios can be narrowed down to a set of reference scenarios by neglecting the scenarios that have no actual effect on the consequence on the basis of a risk matrix across the severity level of consequences of the leakage accidents and their frequency of appearance every year. Next, it is necessary to introduce the concept of equivalent concentration when searching for the five specific distances from do to d4. The value of S tends to be the linear function of the distance in each range, in which the level of severity can be calculated at any point from the installation for any kind of atmospheric conditions. And, finally, in order to take into account the wind rose （i. e., the probability of wind arising in each direction）, we have proposed a procedure that takes into account the probabilities of having wind in each direction, which allows the users to draw maps of severity around an establishment or in a given territory when joining those associated to all the establishments present in that territory. The application of the parameter to a given plant or to a project makes it possible to identify risk levels quickly and establish their comparative ranks.