基于LOPA的安全仪表功能SIL定级方法研究

Study on the Method for SIL Rating of Safety Instrumented Functions Based on LOPA

摘要: 研究了应用保护层分析法(LOPA)评定过程行业中安全仪表功能(SIF)安全完整性等级(SIL)的方法。以某液氨制冷企业冷凝器盘管泄漏风险点为例，说明了此方法的全流程应用过程。研究了LOPA场景识别与筛选、风险后果及严重性评估、初始事件描述及频率确认、独立保护层识别及要求时失效概率(PFD)的确认、场景导致预期后果的频率计算、SIF的SIL等级评定等关键步骤并表格化显示。通过此方法可评估SIF的可靠性，为过程行业企业进行风险评估及风险管理提供依据。

Abstract: This study explores the methodology for assessing the Safety Integrity Level (SIL) of Safety Instrumented Functions (SIF) in the process industry using Layer of Protection Analysis (LOPA). Taking the leakage risk point of condenser coils in a liquid ammonia refrigeration enterprise as an example, the full-process application of this methodology is demonstrated. Key steps, including LOPA scenario identification and screening, risk consequence and severity assessment, initial event description and frequency verification, independent protection layer identification and Probability of Failure on Demand (PFD) confirmation, frequency calculation of scenario-induced expected consequences, and SIL assessment for SIF, are investigated and presented in a tabular format. This methodology enables the assessment of SIF reliability, providing a basis for process industry enterprises to conduct risk assessment and risk management.