Typical air lines
Typical air ducts designed two sections. The first type, having a size of 300X400 mm, used in air volume up to 8500 m31ch, the second tin, having a size of 400X600 mm  with the volume of air supplied over 8500 m3 / h.
Loss of air at the design depend on the length of the duct, the thoroughness of its implementation and the number served by cranes. Minimal loss to the air ducts of less than 100 m is 100% of the volume of air entering the cabin. The total amount of air supplied fresh air system for ventilation of the crane cab L can be determined by the approximate empirical formula L = l, 15LI (n + 70 / [m3 / h], (77)
where L,:  the volume of air supplied to the crane cab, the Martyrs, n  number of cranes, serviced by the system; /  the length of the duct in m calculate the required amount of fresh air for ventilation cabins of three cranes, serviced by one system. When the volume of air to the cabin, LK = 2000 m3 / h and the length of duct = 150 m
L = 1,1520003 + 70150 = 17400 Martyrs.
In this case, the losses amount to 11 400 m3 / h, ie,. about 190% of the volume of air entering the cabin (6000 Martyrs). With two taps and the length of duct = 60 m we
L = 1,1520002 + 7060 = 8800 m31ch,
ie, the losses amount to 120% of the usable volume of air.
Used primarily duct with hydraulic valve and air inlet in the form of a curved pipe is now recognized as irrational. Its significant shortcomings, the complexity of installation and cost. Can not exclude the danger of water freezing and the occasional splashing her, able in some cases lead to an accident.
