Abstract: Large container calibration operations involve capacity measurement of various storage tanks. In petrochemical enterprises, metal storage tanks are widely used in large quantities with varying types and conditions, and most store hazardous chemicals, resulting in high safety risks that must be controlled. An integrated Bow-tie-JSA (Job Safety Analysis) model is established to provide a systematic, streamlined processes, and quantitative safety risk assessment mindset. This study integrates Bow-tie and JSA analytical approaches to analyze root causes of hazardous events from the perspective of energy or hazardous/toxic material release, and identify hazard factors triggering source release as well as potential hazardous incidents. Based on Bow-tie analysis, a risk control model is developed. JSA is conducted for the entire operation process, and referring to the Sinopec risk matrix, the risk value (RI) is quantified to ensure acceptable residual risks. A complete set of standardized operating procedures is thus established to reduce accident probability and ensure safe and efficient large container calibration operations.

Key words: large container calibration, bow-tie analysis, JSA, risk matrix, restricted space operation, risk control