With an improvement in the income levels of people in modern times, their interest in environment and health related issues has also increased. Therefore, the Korean government has endeavored to limit the amounts of contaminants generated and manage the indoor air quality in multiple use facilities and multi-unit dwellings in accordance with the “Indoor Air Quality Standard Administration law for Public Facilities”. However, there are no separate laws concerning such activity areas on ships and marine structures.
In this study, we predicted the diffusion characteristics of the contaminants released by a ship’s ventilation system, and a risk assessment was performed based on the assumptions that environmental contamination occurred and that the contaminants contained fatal nerve agents. In addition, this study used CONTAM 3.2, which is a multizone airflow and contaminant transport analysis software developed by the National Institute of Standards and Technology of the US (NIST), and is an internationally recognized program.
To evaluate the diffusion characteristics of the contaminants from the ship’s ventilation system, the contaminants, the location of occurrence of contamination, and input rate of outside-air flow were used as the prime variables.
The targeted contaminants were benzene and sarin gases, and the places at which these contaminants were found were: the high deck, the middle deck, and the lowest deck. The following five cases of input rate of outside-air flow were considered: 0%, 25%, 50%, 75% and 100%.
Scenarios A, B and C evaluated the characteristics of contaminants spreading on the entire deck, and scenarios D, E and F included the amounts and times of spread of contaminants along with their fatal amounts on each deck.
The time period within which the contaminants were removed was 20-70 minutes depending on the cabins where contamination occurred, and it was affected the most by the change in the input rate of outside-air flow in the Navi.&.Bri decks. The density of the contaminants was lower in the higher decks than in the lower decks by 3 times therefore, the higher decks were considered more dangerous.
The results of this study are expected to be used as base data for heating, ventilation, air conditioning, and improvement of air quality in ships. however, the number of contaminated decks and places was more by over 1.5 times. The contaminants in the higher decks spread faster than in the lower decks