What Is the Safest Hazard Assessment Approach for Distances to Storage Tanks?

Safety in the liquified natural gas (LNG) industry is achieved by four elements: primary containment, secondary containment, safeguard systems, and separation distance from sensitive receptors. The first two elements can be accomplished by appropriate engineering design and robust maintenance programs to minimize the potential for an LNG release. Determining a safe separation distance from a potential release (including secondary containment location) to personnel in buildings is outlined in API RP 752 and 753. This recommended practice provides guidance for managing the hazards from fires, explosions, and toxic releases to personnel in buildings. In the recommended practice, three assessment approaches are utilized: 1) consequence-based approach based on maximum credible events, 2) risk-based approach combining consequences and their frequencies, and 3) spacing tables based on literature data. Each of these assessments vary in their methodology, resulting in different distances to the same hazard. Here, all three approaches are applied to an asset that all LNG facilities have, an LNG Storage Tank. LNG Storage tank failure data is not as prevalent as other plant assets failure data - such as pipeline failures. With a lack of LNG storage tank failure rates, what is the most appropriate method to assess the distances to hazards from an LNG storage tank?