The evaluation of natural ventilation pressure in Korean long road tunnels with vertical shafts

Abstract

NVP analysis was carried out by the thermodynamic method, which is more accurate than the hydrostatic method. Based on this technique, it was found that the greater the differences are as the height of ventilation shaft, temperature, the larger the natural ventilation pressure generated. It was also found that the NVP with a vertical ventilation shaft was much greater than that without a shaft. The NVP with a vertical ventilation shaft may have benefited from passive ventilation by a cost-efficient contaminant elimination method and even minor emergency control method in a long road tunnel using the longitudinal ventilation system. The airflow caused by the NVP was large enough (up to 29.26 % of mechanical ventilation) to increase the efficiency of the ventilation system. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.