概率火灾安全分析方法研究

Study on Probabilistic Fire Safety Analysis Procedures

为分析和评估火灾对设备、建筑物等敏感目标结构安全的影响,结合化工定量风险评估方法和气体爆炸概率安全分析方法,提出概率火灾安全分析策略和实施流程。该方法包括火灾危害辨识、泄漏速率计算、火灾后果模拟、频率分析、绘制频率超越热载荷曲线、结构响应分析等关键步骤。以某柴油罐区为例,通过频率分析和火灾模拟,绘制出频率超越热载荷曲线,假定火灾风险可接受准则为10-4/a,求得对应的可信热载荷为21 kW/m2,并以此值作为结构热响应分析的输入参数。火灾概率安全分析方法侧重于描述火灾热辐射强度及其对应的发生可能性,判定敏感目标遭遇的可信火灾热载荷强度和结构热响应行为,评估消防减灾措施效果,确保结构完整性和可用性,不评价工艺系统潜在火灾风险的高低。

In order to analyze and evaluate fire impact on structural safety of equipment, building and other sensitive objects, strategies and implementation procedures of probabilistic fire safety analysis were proposed with reference to chemical process quantitative risk analysis approach and probabilistic gas explosion study approach. Such procedures included fire hazard identification of key components, leak calcula- tion, consequence simulation, frequency analysis, frequency of exceedance heat load curve establishment and structure response analysis. Probabilistic fire safety study of a diesel tank farm was exemplified, in which frequency analysis and fire scenario simulation with FDS software were completed and frequency of exceedance heat load curve was plotted. If the assumed Risk Acceptance Criteria was 10-4/yr, the corre- sponding fire thermal flux level should be 21 kW/m2, which could be as input value for further structural thermal response analysis. Probabilistic fire safety analysis emphasizes describing fire thermal load and associated likelihood of occurrence, rather than evaluating potential fire risk level of the process system. The objective of probabilistic fire safety analysis is to determine credible heat load and structure response analysis of the sensitive objects exposed to fire, evaluate effectiveness of fire mitigation measures and ensure the integrity and availability of structure.