... 3.Fine performance 4.Good price 5.Satisfactory service Ventilation fan BTXS-36'' --- 56'' ModelDiameterBlades (mm)Air Flow (m3/h)Noise ... strict inspection process: noise inspection, vibration test, concentric performance test, fan blade rotation test, wind capacity test and the efficiency test7 ... ,breeding room,workshop,super market and other spaces for air cooling and ventilation system. Cooling Fan