Aluminium, being a light material (three times lighter than steel), is ideal for specific applications. In paper technologies, large amounts of extremely moist, steam-filled exhaust air is extracted through tightly welded, low-pressure duct systems. With regard to corrosion, AlMg3 is comparable to stainless steel for this type of application. However, being lighter it is less expensive and is a great advantage in respect to the supports and loads that the structure must already bear.