Risk analysis based LNG facility siting standard in NFPA 59A

In the United States, liquefied natural gas (LNG) has the unique distinction of being the only flammable or hazardous material whose storage terminal (siting), handling and terminal operations are regulated by the federal government. Regulations are promulgated by the Pipeline and Hazardous Materials Administration (PHMSA) of the U.S. Department of Transportation (DOT). Storage and handling of all other flammable and hazardous materials are regulated by state laws. Current DOT regulations on LNG (49 CFR, part 193) are based on NFPA 59A, “Standard for the Production, Storage, and Handling of Liquefied Natural Gas,” 2001 edition. These regulations are very prescriptive and inflexible in that they do not allow alternative safety mitigation considerations for LNG facility siting without applying for a special permit. The types and sizes of accidental releases to be evaluated are prescribed and no deviation is allowed. Without considering a spectrum of events, their likelihood of occurrence and the resultant consequences it is impossible to design proper mitigation actions or emergency response procedures. The benefit of knowing and preparing for a properly evaluated “most likely event” scenario is the resultant correct application of economics, and personnel resources of emergency responders.The 2009 edition of NFPA 59A includes, in a mandatory annex, an alternative, risk-based requirements to evaluate the safety of land-based LNG facilities. DOT, in its regulations on the transportation of natural gas in interstate pipelines, requires the conduct of a “Pipeline Integrity Management” procedure to ensure public safety from accidental gas releases from interstate pipelines. The regulations refer to this procedure as “risk-based” even though frequencies of accidents or equipment failures are not considered. The National Association of Regulatory Utility Commissioners (NARUC) and the National Association of States Fire Marshals (NASFM) have recently passed resolutions calling on DOT (PHMSA) to initiate steps towards the development of risk-based LNG facility siting regulations.This paper discusses the risk evaluation approach incorporated into a mandatory annex in the 2009 edition of NFPA 59A and possible other methods of performing a LNG facility risk assessment. Also discussed are the parameters that society has to agree to establish an ‘acceptable’ level of risk. The paper indicates the risk process used in other countries, particularly in Europe. The results from the application of a risk analysis procedure to a specific case are presented. A comparison of the risk-based results with those obtained from the application of the current prescriptive requirements in NFPA 59A (or 49 CFR, part 193) is indicated. Recommendations are provided for future actions.