On the Results of the Risk Assessment Study for Personnel of a Jacket-type Offshore Stationary Platform

Abstract

The study is dedicated to professional risk assessment for personnel of Jacket-type offshore stationary platforms. The study provides an analysis and classification of typical accident scenarios specific to such facilities and includes a forecast assessment of the consequences for 140 employees. Six groups of scenarios have been considered: environmental impacts, fires and explosions, collisions with ships, helicopter crush, cargo drops, and destruction of substructure. Specific attention is paid to a disastrous scenario that involves substructure destruction, which may cause up to 140 fatalities. Individual and social risks have been calculated using two approaches: the quantitative assessment based on statistical data and the semi-quantitative index method (matrix approach). Calculation formulas and computation examples for the two most hazardous scenarios are provided: gas cloud explosion and destruction of the substructure. According to the quantitative calculation, the individual risk for personnel is 1.014·10–4 year, which is at the upper boundary of the ALARP (As Low As Reasonably Practicable) zone, whereas the scenario of substructure destruction makes the dominant contribution (9.5·10–5). Based on the comparative characteristics of the obtained results, the advantages and limitations of each method have been determined. The quantitative method ensures high accuracy and comparison with standards, but is labor-intensive, whereas the semi-quantitative method allows rapid risk ranking. The authors suggest a combined approach: the index method for hazard identification at the first stage and a detailed quantitative analysis of critical scenarios at the second stage, which enables efficient safety and platform structure integrity management.