(55a) Fire on All Cylinders: Pool Fire Modeling for LNG Plants

LNG facilities must comply with 49 CFR 193 regulations. 49 CFR 193.2057 specifies that LNG facilities must have a thermal exclusion zone in accordance with section 2.2.3.2 of NFPA-59A-2001 and specify that the only computer program approved for calculating thermal radiation exclusion zones is LNGFIRE3, which uses a simple point source model and can only model LNG pool fires. However, the use of other alternate models which take into account the same physical factors and have been validated by experimental test data may be permitted subject to the Administrator's approval. The computational fluid dynamics (CFD) modeling tool FLACS, already approved by DOT-PHMSA for vapor-gas dispersion exclusion zone calculations, has extended its capabilities to include fire modeling. The ability of the FLACS software to handle detailed 3D geometry provides for the evaluation of thermal radiation mitigation measures, as well as tracking exposure to equipment and buildings located within the facility. Thermal radiation from pool fires can damage equipment and lead to escalation. Efficient and detailed modeling of pool fires is critical to improving safety at LNG plants and can be helpful for evaluating mitigation options. Pool fire scenarios typical of LNG plants will be presented, with a focus on protecting pressure vessels.