Layer of Protection Analysis (LOPA) has an important place in Safety Integrity Level (SIL) analysis as a key risk assessment tool. However, the inherent limitations of LOPA, especially the over-reliance on conservative assumptions, may lead to unrealistic results, especially in cases where there are issues of independence between initial events and protection layers. These assumptions are not always applicable, especially when there are shared components in the system, and traditional LOPA approaches may not accurately reflect the risk. Therefore, this paper proposes a new method that combines Fault Tree Analysis (FTA) with LOPA, aiming to deal with shared components more rationally and improve the accuracy of risk assessment. Through a case study of batch filling of butane spherical tanks, this paper demonstrates a scenario in which the use of a single piece of equipment to perform multiple tasks in LOPA analysis may lead to inaccurate results, and demonstrates how the accuracy of risk calculation can be improved through FTA analysis. It is shown that the combination of FTA and LOPA can effectively address the limitations of the traditional LOPA method, provide more accurate risk assessment results, and offer a more reliable basis for safety decision-making in complex systems.

保护层分析（LOPA）作为一种重要的风险评估工具，在安全完整性等级（SIL）分析中具有重要地位。然而，LOPA的固有局限性，尤其是对保守假设的过度依赖，可能导致其产生不切实际的结果，特别是在涉及初始事件和保护层之间的独立性问题时。但假设并不总是合理的，尤其是在系统中存在共享组件时，传统LOPA方法可能无法准确反映风险。为此，提出了将故障树分析（FTA）与LOPA相结合的新方法，旨在更合理地处理共享组件，提升风险评估的准确性。通过丁烷球罐批量充装的案例研究，展示了在LOPA分析中使用单一设备执行多项任务可能导致不准确结果的情形，并通过FTA分析演示了如何改进风险计算的准确性。研究表明，FTA与LOPA的结合能够有效解决传统LOPA方法的局限性，提供更精确的风险评估结果，为复杂系统的安全决策提供更为可靠的依据。