CFD-based consequence assessment of fires following rupture of natural gas transmission pipelines

Gas transmission pipeline ruptures are low-frequency and high-consequence events which cause fire impingement and extreme thermal radiation. These intense external fires substantially impact people, structures, and the environment. Existing consequence assessment of these types of fires is mainly based on simplified fire hazard models, such as the Potential Impact Radius (PIR) equation. The PIR equation is derived from a single-point source jet fire model under idealized release conditions and vertical jet flame behavior, representing the consequence area as a symmetric radial footprint. Such assumptions may not accurately reflect the elongated and highly directional nature of jet fires. To perform an accurate consequence assessment, detailed modeling of flame propagation, momentum, and thermal radiation distribution is required. For this reason, this study employed Computational Fluid Dynamics (CFD) modeling. An actual fire resulting from a pipeline rupture incident was simulated using the Fire Dynamics Simulator (FDS) to evaluate the spatial distribution of heat flux and hazard zones for a laterally oriented jet flame. The FDS model replicated the consequence area similar to the actual damage observed in the incident. This study contributes to establishing a direct link between fire dynamics (jet fire and radiation) and the consequences resulting from pipeline rupture. This enables scenario-based consequence assessment of human and building (both existing and new construction) vulnerability under these extreme fire conditions. The findings enable more rigorous risk quantification by refining current methodologies for estimating thermal hazard zones in high-pressure gas transmission failures. In addition, it suggests scenario-based consequence zones for pipeline-adjacent communities, reducing the likelihood that future ruptures translate into catastrophic building damage.