Analysis of the Method for Enhancing Safety by Predicting and Comparing Damage Ranges Due Owing to Chemical Leakages

To predict the extent of damage caused by leakages at a place where chemicals are wholesaled, four of the most commonly stored substances in the corresponding place were selected. Leakage volumes were increased by 50 ㎘, and methyl alcohol, ethyl acetate, and methyl ethyl ketone were confirmed by increasing the leakage volume to 100 ㎘ and to 160 ㎘ for toluene. A total of 92 scenarios were created by applying the region’s average temperature, wind speed, wind direction, and humidity over the last 10 years to confirm each substance’s diffusion distance. The prepared scenario was analyzed by applying ALOHA air dispersion models. Regarding toxicity, criteria were analyzed based on each substance’s PAC-1, PAC-2, and PAC-3 concentration, and a fire occurrence possibility range was used to maintain the concentration of the lower flammable limit. Under normal conditions, in the case of the same amount of leakage, the concentration of the lower flammable limit and PAC-1 was maintained farthest from toluene, but the danger distance of methyl alcohol was farther in PAC-2 and PAC-3. Results showed that the diffusion distance increases the log function with the amount of leakage. However, owing to the substances’ toxicity and physical characteristics, the PAC levels of some substances showed non-uniform results. In addition, diffusion widths differed for each substance. Therefore, to prescribe countermeasures for chemical leakages in storage locations, all substances being stored must be checked. Disaster prevention measures must also be established by considering not only diffusion distances of the substances but also their diffusion widths.