Abstract
Recent accidents with a catastrophic impact on Safety and Environment in the Oil & Gas (O&G) and Oil Refining industries has prompted the Regulators and the Process industry to move an important step forward to ensure to the Communities and the industry stakeholders that the risk of these accidents will be as lowest as reasonably practicable. As model for the approach between Regulators, Industry and Trade Unions in UK after the Buncefield accident the Process Safety Leadership Group (PSLG) issued in 2009 the "Safety and environmental standards for fuel storage sites" Final Report. The PSLG Final Report followed the pathway of Buncefield Standards Task Group (BSTG) by providing safety recommendations focused on improving safety in the design and operation of fuel storage sites. The PSLG Final Report safety recommendations are suitable to turn the safety investment into effective incident prevention. In this paper the PSLG Final Report safety recommendations related to the functional safety issues (reference is made to PSLG Final Report Part 1 "Systematic assessment of safety integrity level requirements" with specific reference to Appendix 2 and Part 2 "Protecting against loss of primary containment using high integrity systems"with specific reference to Appendix 4) are examined in detail aimed to conceive a safety instrumented system to enhance the Safety and Environment protection in fuel storage sites in full compliance both with the PSLG and International Standard IEC 61511 (2003) requirements. The overfill protection system for flammable fuel storage tanks of bulk hazardous liquids such as specifically gasoline and other materials such as naphtha, reformate, light crude oil, others likely to form a large vapour cloud, is examined in detail with a specific focus on safety integrity level assessment by LOPA (layers of protection analysis) method in compliance with the PSLG Final Report guidelines and IEC 61511 (2003) requirements.
