(32al) Evaluating Safety of Atmospheric Venting for Low-Pressure Tanks: A Semi-Quantitative Screening Approach

Pressure relief vents for low-pressure tanks are typically designed to discharge into the atmosphere rather than a closed disposal system due to factors such as cost, physical limitations, etc. However, this practice can lead to the release of flammable and/or toxic materials, creating potential hazards for personnel and the public. Conducting detailed dispersion modeling for every relief case to assess whether the vent discharging to atmosphere is safe can be both time-consuming and labor-intensive. To address this, this paper proposes a semi-quantitative screening method for evaluating the safety of tank venting to atmosphere. The author conducted a series of case studies to analyze the influence of various factors on atmospheric venting, including the concentration of flammable and/or toxic substances in the tank's vapor space, discharge piping configuration, exit velocity, wind speed, etc.