Compressed-air is your best option to choose when it comes to cleaning round as well as rectangular shafts and air ducts. The compressed-air cleaning devices are available in different sets. Round and oval pipes can be effectively cleaned by the backward rotating helicopter nozzles. The air whips are being used in rectangular shafts and angular air ducts, where they loosen even firmly bond dust. The used compressor should be capable of a permanent output capacity of at least 5 bar at a minimum volume flow of 25 ³/h.