The bow tie method in assessing occupational risks

Abstract

The Ministry of Labor recommendations for assessing occupational risks suggest 13 methods, among which is the bow tie technique. The employer chooses a method for assessing occupational risks, taking into account a large number of parameters, including the degree of danger of works performed and possible consequences of risks. The bow tie method specifies the risks of high-risk production operations and analyzes the effectiveness of safety barriers. The purpose of the study is to apply the "bow tie" method in assessing the occupational risks and to develop ways to minimize them. The method is analyzed on the example of works performed during oil production. We used the statistical data of the Federal Service for Ecological, Technological and Nuclear Supervision to identify the most common causes of accidental hydrocarbon leaks. We modelled incident trees and event trees to assemble bow tie models and analyze security barriers. This method was used to assess the risk of accidental releases of hydrocarbons. The incident tree was developed for the emergency release of hydrocarbons caused by the leakage of hydrocarbons from apparatuses, violations of the integrity of pipelines and tanks, depressurization of flanged and welded joints. Trees of events take into account equipment characteristics, possibilities of the method for assessing probabilities of both hazards and consequences. Security barriers were developed. They can be used in developing ways to minimize and assess risks. For the emergency release of hydrocarbons, the bow tie models show that a whole set of modern safety systems is required to ensure safety during oil and gas treatment operations.