Train tunnels and subways are an interesting field of ventilation. Trains move air through tunnels at rates of 600 m³/s (over 2 x 10^6 m³ per hour) which is much more than flow rates in buildings. Air pressures can vary up to some 3000 Pa leading to air velocities in the range of 10 to 50 m/s. This can lead to unsafe situations and thermal discomfort. The development of high speed trains causes more concern for better tunnel design. Modern stations often house small shops and restaurants, that require lower air velocities for thermal comfort.
Login