Ventiflex Tunnelcalc is a simple tool, to determine the recommended duct-diameter, with additional information of approximately fan-size and working air pressure. This calculator is based on SIA recommendations, and the latest European norms, for tunnel ventilation.
Basically are there three key-figures necessary to operate this calculator: (To be entered into the light blue fields)
Other figures will automatically appear, based on these three figures, and indicate recommended duct diameter.