大型游乐设施风险评估与分级方法研究

大型游乐设施的运行是一个动态管理过程,不仅涉及设备本身,而且与人、环境等因素密切相关。针对这个特点,提出大型游乐设施风险矩阵(RMM)的风险分级方法。提出了将事故树与模糊数学相结合的模糊事故树法(FFTA);采用3σ模糊表征法计算大型游乐设施各类风险事故的概率;再采用信息熵法来评价大型游乐设施的风险后果;最后利用风险矩阵法来确定大型游乐设施的风险等级,并通过实例验证了该分级模型有效。     

风险严重度指数法在毒气泄漏评价中的应用

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.     

山岭隧道施工中塌方风险评估模型研究及应用

为评估隧道施工中塌方风险,以确定其可能性及严重程度作为2条主线。由文献调研并结合待评估隧道风险特征、施工现状、工程概况等建立塌方可能性评估指标体系,运用层次分析法(AHP)与多层次模糊综合决策确定塌方风险事件可能性等级,定性指标由专家评判确定对各可能性等级的隶属度,定量指标的隶属度以正态分布作为隶属函数求出;综合考虑多种事故后果类型,选用当量估计法确定塌方风险事件严重程度;最后基于风险矩阵法确定隧道塌方风险等级。将本模型应用于兴隆隧道1号斜井,经评估该斜井塌方风险等级为Ⅲ级,即较大风险,后续施工中须采取有效措施降低风险,减少风险可能导致的损失。     

基于模糊Bow-tie模型的深水海底管道定量风险评价研究

为有效评价深水海底管道风险,提出一种新的模糊Bow-tie模型定量风险评价方法。综合运用Bow-tie图、模糊集以及德尔菲法,定量分析油气泄漏概率。进一步利用层次分析法(AHP)研究油气泄漏后果的严重程度,给出泄漏后果因素的权重系数选择方案。同时,结合风险矩阵,实现对高风险深水海底管道的定量风险评价。将上述方法用到具体海底管道工程中,得出目标海底管道泄漏概率属于A级,泄漏后果属于Ⅲ级,泄漏风险为高风险,这一结果与实际情况较为符合。     

油气输送管线失效后果模糊事件树分析

油气管线失效后果发生概率是管线风险评价的重要参数,可以通过事件树定量分析来确定管线失效概率和各后续事件发生概率,但这些数据往往因缺乏完整的事故统计资料而难以确定,为此提出采用模糊集合理论与专家语言判断相结合的方法来量化各后续事件发生的可能性。基于构建的油气长输管线失效后果通用事件树,利用模糊事件树分析法替代传统事件树分析法来确定失效后果发生概率,并基于模糊重要度指数和模糊不确定性指数对后续事件进行重要性分析。结果表明,利用该方法可得到管线失效后果发生概率的量化结果,能辨识重要的后续事件。     

铁路隧道TBM施工风险评估

采用基于熵权的模糊综合评估模型对西秦岭特长铁路隧道TBM施工风险进行分析,识别关键风险因素并提出施工应对策略。首先结合西秦岭隧道项目工程特点,参照《铁路隧道风险评估与管理暂行规定》进行TBM施工风险识别,将其归结为设备风险、掘进风险、辅助工序风险三大方面,对每个方面细分出4项一级风险因素。接着确定各层次风险因素权重:借助专家调查确定一级风险发生的概率等级,运用熵权法确定底层风险权重;运用层次分析法确定三大方面风险权重。最后建立二级模糊综合评判模型,评估西秦岭铁路隧道右线的施工风险等级。通过现场专家调查得到的一级风险因素后果损失等级表建立一级评判隶属度矩阵,进行一级模糊评判;并将结果作为二级评判因素的评价集,进行第二级综合评判,评定该项目为2级风险。同时借助熵权反映底层各风险因素的重要程度,确定关键风险因素并判断其风险等级,提出施工应对措施。     

基于模糊数学的石油化工装置HAZOP风险分析技术研究

对传统的HAZOP分析中偏差原因发生可能性进行量化。对于有统计数据的,根据行业数据、公司经验及企业事故建立HAZOP风险分析统计数据库;对于没有统计数据的HAZOP分析偏差原因发生概率,通过专家主观评判,用模糊数理论将专家自然语言转换为模糊数,采用左右模糊排序法将模糊数转换为模糊失效概率值。研究了偏差后果严重程度的划分标准,并根据偏差原因概率和偏差后果严重程度确定风险等级,利用风险矩阵得出偏差风险的大小。从而把HAZOP分析方法从定性改进为半定量的分析方法。据此对石油化工装置进行了HAZOP风险分析。     

钢铁企业动力管道物理爆炸事故风险模糊综合评判

以风险评价理论为基础,根据事故风险率由事故发生可能性和严重性共同确定的原则,应用模糊关系合成原理将影响事故发生可能性和严重性的风险因素进行定量描述,同时应用层次分析法确定各因素权重,建立了钢铁企业动力管道物理爆炸事故风险模糊综合评判模型,最终应用风险矩阵法直观显示出该事故的风险等级。以某钢铁企业为例说明完整的动力管道物理爆炸事故的风险模糊综合评判过程,模型计算结果基本反映该钢铁企业动力管道物理爆炸事故的风险实际水平。     

油气行业风险矩阵货币形式量化制定与应用分析

为解决现有风险矩阵应用过程中存在的定性分析结果简单、应用性差等问题,提出一种全新的定量风险矩阵制定流程。参考相应的法律法规和地方行业标准,从人员、环境、财产3方面划分事故后果严重等级。并以货币形式量化后果严重程度,用权重赋值法计算各事故后果等级对应的货币损失值并分级,然后按风险等级系数对事故场景危险性进行排序。以某大型燃气公司的企业风险矩阵制定为案例,对比传统风险矩阵和改进后的事故矩阵。结果表明,改进后的风险矩阵分析结果更加清晰明了,有助于更合理地分配安全资源并计算成本,从各事故场景风险等级排序中找出最危险场景。     

定量风险评价技术在海底管道中的应用

根据风险工程理论,综述了多种海底管道定量风险评价技术.着重研究了模糊综合评分和蝴蝶结模型在海底管道油气泄漏概率计算及后果分析中的综合运用,建立了基于泄漏物危害及影响系数的泄漏后果严重度模型,结合风险矩阵实现定量风险评价.同时,该评价方法对工程实践具有一定的指导意义.     

Fuzzy logic for piping risk assessment (pfLOPA)

This paper explores the application of the fuzzy logic for risk assessment of major hazards connected with transportation of flammable substances in long pipelines. As a basis for risk assessment, the framework of the fuzzy Layer of Protection Analysis (fLOPA) was used. fLOPA presents a new approach to risk assessment based on two assumptions: 1. different effects of the layer of protection functions on particular elements of the risks (frequency and severity of consequence), and 2. the application of fuzzy logic system (FLS) composed of three elements: fuzzification, inference process and defuzzification. A further calculation follows LOPA methodology with the use of fuzzy logic system where fuzzy risk matrix is used for risk assessment. A typical case study comprising section of a long pipeline failure is performed and a comparison between the classical LOPA approach and fuzzy approach is made.     

Uncertainty aspects in process safety analysis

Uncertainties of input data as well as of simulation models used in process safety analysis (PSA) are key issues in the application of risk analysis results. Mostly, it is connected with an incomplete and uncertain identification of representative accident scenario (RAS) and other vague and ambiguous information required for the assessment of particular elements of risk, especially for determination of frequency as well as severity of the consequences of RAS. The authors discuss and present the sources and types of uncertainties encountered in PSA and also methods to deal with them. There are different approaches to improve such analysis including sensitivity analysis, expert method, statistics and fuzzy logic. Statistical approach uses probability distribution of the input data and fuzzy logic approach uses fuzzy sets. This paper undertakes the fuzzy approach and presents a proposal for fuzzy risk assessment. It consists of a combination of traditional part, where methods within the process hazard analysis (PHA) are used, and “fuzzy part”, applied quantitatively, where fuzzy logic system (FLS) is involved. It concerns frequency, severity of the consequences of RAS and risk evaluation. In addition, a new element called risk correction index (RCI) is introduced to take into account uncertainty concerned with the identification of RAS. The preliminary tests confirmed that the final results on risk index are more precisely and realistically determined.     

基于风险的城市埋地燃气管道安全评价模型及应用

城市埋地燃气管道一旦失效会产生泄漏,甚至引发火灾爆炸等事故,造成人员伤亡和财产损失等严重后果,影响社会稳定,因此其安全运行十分重要。由于城市地下环境的复杂性,使得埋地燃气管道失效的因素多种多样,且具有模糊性;由于城市地面状况各异,所以构成失效后果的因素也具有不确定性。文章以某市在役燃气管道为例,使用模糊数学语言表达了埋地燃气管道的失效可能性和失效后果,采用模糊综合评价模型对燃气管道的失效可能性和失效后果进行了评价,并以美国石油协会(API)风险矩阵表征了埋地燃气管道的风险等级,得到不同管道单元的风险级别和管道单元数,根据不同的风险等级采取不同的策略或措施,完善管道的完整性管理,降低管道的使用风险,确保城市燃气管网的正常安全运行。     

SPA–fuzzy method based real-time risk assessment for major hazard installations storing flammable gas

For monitoring and control of major hazard installations storing flammable gas, the risk based warning/early-warning is very important. A set-pair analysis (SPA) based fuzzy assessment method (SPA–fuzzy) is proposed for the real-time risk assessment in this paper. Based on principle of SPA and fuzzy logic theory, the likelihood of accident occurrence and the consequence of the accident can be assessed, and the risk value or risk degree can be evaluated. The method takes advantage of the data acquired from the real-time safety monitoring system, so that the varying of the risk can be revealed during an accident developing. The risk assessment simulation of VCE accident caused by gas leaked from LPG tank is performed. It is shown that SPA–fuzzy method has the same risk value as that assessed by normal fuzzy method.     

Application of fuzzy logic to explosion risk assessment

Safety and health of workers potentially being at risk from explosive atmospheres are regulated by separate regulations (ANSI/AIHA in USA and ATEX in the European Union). The ANSI/AIHA does not require risk assessment whereas it is compulsory for ATEX. There is no standard method to do that assessment. For that purpose we have applied the explosion Layer of Protection Analysis (ExLOPA), which enables semi-quantitative risk assessment for process plants where explosive atmospheres occur. The ExLOPA is based on the original work of CCPS for LOPA taking into account an explosion accident scenario at workplace. That includes typical variables appropriate for workplace explosion like occurrence of the explosive atmosphere, the presence of effective ignition sources, activity of the explosion prevention and mitigation independent protection layers as well as the severity of consequences. All those variables are expressed in the form of qualitative linguistic categories and relations between them are presented using expert based engineering knowledge, expressed in the form of appropriate set of rules. In this way the category of explosion risk may be estimated by the semi-quantitative analysis. However, this simplified method is connected with essential uncertainties providing over or under estimation of the explosion risk and may not provide real output data.In order to overcome this problem and receive more detailed quantitative results, the fuzzy logic system was applied. In the first stage called fuzzification, all linguistic categories of the variables are mapped by fuzzy sets. In the second stage, the number of relation between all variables of analysis are determined by the enumerative combinatorics and the set of the 810 fuzzy rules “IF-THEN” is received. Each rule enables determination of the fuzzy risk level for a particular accident scenario. In the last stage, called defuzzification, the crisp value of final risk is obtained using a centroid method. The final result of the risk presents a contribution of each risk category represented by the fuzzy sets (A, TA, TNA and NA) and is therefore more precise and readable than the traditional approach producing one category of risk only. Fuzzy logic gives a possibility of better insights into hazards and safety phenomena for each explosion risk scenario. It is not possible to receive such conclusions from the traditional ExLOPA calculation results. However it requires the application of computer-aided analyses which may be partially in conflict with a simplicity of ExLOPA.The practical example provides a comparison between the traditional results obtained by ExLOPA and by fuzzy ExLOPA methods.     

基于模糊层次分析法的编队内碰撞风险评价模型研究

编队内碰撞是编队飞行最大的安全威胁。为解决编队飞行灵活性与编队飞行安全的矛盾,建立了编队内各机碰撞风险评价模型指标体系,使用模糊互补判断矩阵确定了各指标的碰撞权重,实现了编队内各机碰撞的风险评估。以空军航空兵某部一架机型G与一架机型H混合双机编队为例进行了实证研究,结果表明,该模型简便易操作,可提高编队飞行训练效率。     

Real-time risk assessment of explosion on offshore platform using Bayesian network and CFD

Combustion or explosion accident resulting from accidental hydrocarbon release poses a severe threat to the offshore platform's operational safety. Much attention has been paid to the risk of an accident occurring over a long period, while the real-time risk that escalates from a primary accident to a serious one was ignored. In this study, a real-time risk assessment model is presented for risk analysis of release accidents, which may escalate into a combustion or explosion. The proposed model takes advantage of Fault Tree-Event Tree (FT-ET) to describe the accident scenario, and Bayesian network (BN) to obtain the initial probability of each consequence and describe the dependencies among safety barriers. Besides, Computational Fluid Dynamics (CFD) is applied to handle the relationship between gas dispersion and time-dependent risk. Ignition probability model that considering potential ignition sources, gas cloud, and time series are also integrated into this framework to explain the likelihood of accident evolution. A case of release accidents on a production platform is used to test the availability and effectiveness of the proposed methodology, which can be adopted for facilities layout optimization and ignition sources control.