(144a) Evaluation of Dispersion Models for LNG Siting Applications

The federal safety standards for LNG facilities under 49 CFR Part 193 approves the use of specific dispersion models for performing vapor-gas dispersion exclusion zones.  In addition, provisions allow for the use of alternative models if approved by PHMSA.

In 2010, PHMSA, in consultation with FERC, issued Advisory Bulletin ADB-10-07 to provide guidance on obtaining approval of alternative models under Part 193.  The guidance is based on the Model Evaluation Protocol (MEP) described in the Fire Protection Research Foundation Reports, Evaluating Vapor Dispersion Models for Safety Analysis of LNG Facilities (2007) and Guide to the LNG Model Validation Database (2009, 2010).  This method has been applied to several dispersion models to establish limitations and safety margins, which would allow it to be used in Part 193 exclusion zone calculations.

This presentation examines the results of the reviews conducted by PHMSA and FERC, including the basis for the limitations and safety margins.