**2. Maintenance decision method based on risk level**

#### **2.1 Definition of evaluation indexes and scoring criteria of risk level**

Through the FMECA of the mechanical equipment in the petrochemical industry, from the four aspects of reliability, economics, monitorability, and maintainability, 10 influencing factors directly related to its risk level were analyzed, as shown in **Table 1** [10].

In order to ensure that the evaluation of the risk level of machinery and equipment is not too complicated, and that the accuracy of evaluation is balanced, and
