PresentationA Maritime Safety Zone is defined by the U.S. Coast Guard as a water area, shore area, or water and shore area combined to which, for safety or environmental purposes, access is limited to authorized persons, vehicles, or vessels. A Maritime Safety Zone is established to prevent interference with safe navigation and tug maneuvers, to exclude third party access in order to reduce ignition probability, to aid in emergency preparation, and to protect the public from being exposed to potential harm. USCG also defines a Maritime Security Zone for protection against intentional threats, and this is usually larger than the Safety Zone. The USCG requires that a Maritime Safety Zone be defined before a Letter of Recommendation is given. While the Canada Marine Act only suggests that a port authority may establish Traffic Control Zones, the USCG suggests using the Sandia study as guidance for determining Maritime Safety and Security Zones. Though there are guidance documents, no standard method is currently available for determining site specific Maritime Safety Zones applicable to accidental spills that could occur at the waterfront configuration of the terminal. A common methodology would enable Safety Zones to be more properly defined and create safer waterways. Two types of approaches have been proposed by DNV GL in this paper to determine the Safety Zones surrounding LNG terminals from accidental spills. A deterministic approach is based on a single maximum credible event among a set of representative scenarios that have been modeled. This approach may conservatively produce a very large hazard distance depending on the consequence of the maximum credible scenario. A probabilistic approach is a risk based approach which associates the consequence (the thermal radiation intensities and the flammable vapor dispersion distances) with the likelihood of having such a consequence. A probabilistic approach provides a more realistic basis for making informed decisions
