Low Concentration of Oxygen in External Environment - Modeling the Consequences of Accident

Abstract

The lack of oxygen (asphyxiation) usually occurs inside the device. However, literature describes several accidents that occurred in an outdoor environment. According to the information EIGA (European Industrial Gases Association) several tens of cases of asphyxiation per year in average occur in the chemical industry. [1] Although these accidents usually have only local effects, in a few cases the release of large quantities of chemicals to the external environment affects external workers. This article presents several examples of accidents that can affect the surroundings of technological equipment, discusses the possibility of modeling the accident and determines the extent of the consequences. This article also summarizes the information needed to calculate the severity of the reduction in oxygen concentration and describes the typical accident scenarios that can lead to a reduction in the concentration of oxygen in the environment. These three scenarios are modeled in ALOHA software. The results show that only one scenario, i.e. biphasic spillage of liquid nitrogen and subsequent evaporation from the reservoirs, can affect the population living in the vicinity of the equipment. Based on these results, preventative measures are proposed.