(37a) VCE Potential Cascade Effects – Part 2

The LNG industry has historically maintained a high degree of safety in its operations. This has been built on a clear understanding of the hazards associated with LNG processes, storage and transportation. A vapor cloud explosion (VCE) occurs following the ignition of significant vapor clouds formed by accidental release of flammable fluids and can involve generating damaging overpressures. LNG, which in its vapor form is natural gas, is inherently safer in this respect compared to other fuels, but this does not remove the need to consider these events.

A key aspect of a VCE is that the resulting damaging overpressures can cause further failures in equipment and as a result, the initial incident escalates. These ‘Cascade Effects’ can significantly increase the severity and extent of a VCE event. Understanding the potential for Cascade Effects on LNG facilities can inherently improve safety, protecting both people and key energy infrastructure. The US DOT PHMSA commissioned a research project to evaluate the severity of potential explosions and the response of structures to exceptional loads. DNV and Thornton Tomasetti partnered to conduct the research project starting in Q3 2020.

DNV performed dispersion and explosion modeling with CFD to evaluate the potential extent of explosion loads from flammable materials present at LNG facilities. Finite Element Analysis (FEA) modeling was performed by Thornton Tomasetti to evaluate the structural response of representative equipment to overpressure loads.

At the 2022 conference, intermediate results and the research to date were presented. The conference paper in 2023 will summarize the outcomes of the research and the resulting overall findings and conclusions based on the research. The research is meant to provide guidance on assessing the potential for Cascade Effects and potential mitigation options.

This work was funded in part, under the Department of Transportation, Pipeline and Hazardous Materials Safety Administration. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Pipeline and Hazardous Materials Safety Administration, the Department of Transportation, or the U.S. Government.