THE DEVELOPMENT OF A RISK ASSESSMENT MODEL TO COMPARE OIL SPILL RISK FOR SINGLE & DOUBLE HULLED FPSOS

Abstract

ABSTRACT In recent years, following a number of high profile oil spills internationally, there has been an increased focus on improving the safety of oil tankers to prevent the environmental damage caused by oil spills. Regulations developed focus on replacing single hulled trading tankers with a double hulled configuration. However, many of the risks associated with trading tankers do not apply to Floating Production, Storage and Offloading vessels (FPSOs). The risk assessment undertaken for this report compares single with double hull FPSOs, with respect to events causing serious environmental impact. The study considers external and on-board causes of events which may cause serious oil spills including fire, explosion, accidental discharge, grounding, collision and hull failure. The risk assessment comprises a limited quantitative analysis using data from the literature and observations from experience, which are consistently applied to each of the hazardous events identified as relevant. The report also looks at the wider environmental factors associated with single versus double hull FPSOs in order to inform policy makers. The findings indicate that risk profiles of oil tankers are markedly different from FPSOs, and that there is a strong argument that overall environmental risks from a single hull FPSOs are lower than those for a double hulled F?SO. A single sided hull has potentially better structural performance; no risk of inter-hull formation of volatile explosive mixtures; delivers environmental benefits; and has simpler operational requirements than a double sided FPSO. The main advantage for using a double sided hull is the higher collision impact energy it can withstand without releasing oil into the environment.