Designing the ventilation system of tunnel No. 2 of the third section of the main road Pataveh-Dehdasht during utilization

Tunnel ventilation is essential in utilization. Because it provides safety and comfort for traffic in the tunnel, no tunnel or underground passage can be used safely and healthily without a proper and efficient ventilation system. In this research, the best ventilation system of tunnel number 2 of the main road from Pataweh to Dehdasht (third section) in the southwest of Kohgiluyeh and Boyer Ahmad province was designed during operation. First, by using different standards, the necessity of using mechanical ventilation in this tunnel was determined, and considering the advantages of using longitudinal ventilation, this ventilation method was selected for the tunnel. Using the classic techniques and the PIARC method, the required flow intensity for tunnel ventilation was calculated. Then, considering different pressure components, the necessary pressure drop was also obtained. Statistical analysis was used to obtain the final flow intensity, and finally, the value of 155 cubic meters per second was obtained as the necessary airflow intensity in the tunnel. The total pressure drop in this tunnel is equal to 47 Pa. According to the calculations, the specifications of several fans were checked, and finally, 9 fans' model 900/403-6 from Novenco company were selected..