Evaluation of Accidental Atmospheric Releases of Chlorine and Butane from a Mobile Source Using ALOHA and MARPLOT

Noura Mohammad Al-Sarawi

doi:10.11648/j.ajep.20170606.12

Abstract

The purpose of this paper is to evaluate the extend of the threat zone of two mobile accidental atmospheric releases of chlorine and butane on the I-95 Highway by estimating the downwind dispersion of the chemical plumes using the numerical model ALOHA (Area Locations of Hazardous Atmospheres) and by graphing the boundaries of the threat zone using MARPLOT (Mapping Application for Response, Planning, and Local Operational Tasks). In addition, to assess the risk of exposure at two points of interest from the chlorine accident, and to measure the extent of the flammable zone; the area where a flash fire or a vapor cloud explosion could occur at some point after the release begins, resulting from the butane accident. Moreover, the aim is to study the stability class effect on indoor and outdoor concentrations and its effect on distance of the flammable zones. The paper conclude that the stability class has a significant effect on the prediction of the size of the toxic threat zone under different atmospheric dispersion conditions. In addition, the size of the area impacted after a chemical release depends on the characteristics of the chemical along with the meteorological and atmospheric conditions.

Highlights

Over one million hazardous material shipments are carried mostly by trucks, containing toxic and flammable liquids or gases daily in the United States [1]
Numerical dispersion models and the prediction of fate and transport of chemicals released into the atmosphere is a very crucial research area because of the threats on human health and the environment accompanied by accidental release of hazardous substances
The estimated maximum indoor concentration at this location is 0.267 ppm, which is below the 10-min AEGL-1 value for chlorine (0.5 ppm)

Summary

Introduction

Over one million hazardous material shipments are carried mostly by trucks, containing toxic and flammable liquids or gases daily in the United States [1]. According to the U.S Department of Transportation Pipeline and Hazardous Materials, 4,533 in transit accident, 289 in transit storage, 3,292 loading, and 8,361 unloading spills occurred only in. Numerical dispersion models and the prediction of fate and transport of chemicals released into the atmosphere is a very crucial research area because of the threats on human health and the environment accompanied by accidental release of hazardous substances. ALOHA was developed by the United States Environmental Protection Agency and the National Oceanic and Atmospheric Administration to assist chemical emergency planners and responders. It can simulate the dispersion for over 900 chemicals and is primarily used in the

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Conclusion