Division 1.1.1 F1
A variable speed current of air shall be blown towards the vehicle. The set point of the linear velocity of the air at the blower outlet shall be equal to the corresponding roller speed above roller speeds of 5 km/h. The linear velocity of the air at the blower outlet shall be within ± 5 km/h or ± 10 per cent of the corresponding roller speed, whichever is greater.