Layers of Protection Analysis (LOPA) method and application of risk analysis

The CNPC has advanced the Hazard and Operability Analysis (HAZOP) method on several refinery enterprises in recent years. The Layers of Protection Analysis (LOPA) method is integrated into the HAZOP on the basis of that there is still existing insufficient on HAZOP. The LOPA can realize semi-quantitative evaluation of risk by means of HAZOP results. This article introduces the concept of LOPA, occasion of using LOPA, what are the layers of protection and the Independent of Protection Layers (IPLs), the procedure of LOPA, the advantage and limitation of LOPA, and so on. Through an example of carrying on the LOPA on the results of HAZOP, the work is listed in details step by step according to the procedure of LOPA.