Analysis of vapor barrier experiments to evaluate their effectiveness as a means to mitigate HF cloud concentrations

Abstract

Accidental release of Hydrogen Fluoride (HF) can result in initially dense, highly reactive and corrosive gas clouds. These clouds will typically contain a mixture of gases, aerosols and droplets which can be transported significant distances before lower hazard levels of HF concentration are reached. Previous related field and laboratory experiments have been analyzed to estimate the effectiveness of barrier devices. The experiments were examined to determine their relevance to Hydrogen Fluoride spill scenarios. Wind tunnel and field data were compared where possible to validate the laboratory experiments. Barrier influence on peak concentrations, cloud arrival time, peak concentration arrival time, and cloud departure time were determined. These data were used to develop entrainment models to incorporate into integral and depth averaged numerical models. The models were then run to examine barrier performance for a typical Hydrogen Fluoride spill for a wide range of vapor barrier heights, spill sizes, meteorological conditions and release configurations. Finally the results of the data analysis and numerical sensitivity study were interpreted and expressed in a form useful to evaluate the efficiency of vapor barrier mitigation devices.