The most common and internationally known types of duct are the followings:
Sheet metal ducts
Usually available in variable sections and dimensions, normally manufactured in the factory and later assembled in the construction site. If the thermal insulation is needed, they are coated with glass wool or neoprene mattresses. Characterized by a strong but heavy structure, they represent the most common and historical system.
Ducts realized using sandwich panels made of an insulating layer coated on one or more sides; they are workable and can be assembled both in the factory and in the construction site. They present technical performances which vary according to the type of insulation and selected coating.
Polyurethane and aluminium pre-insulated ducts
Ducts realized using sandwich panels in aluminium and PUR expanded polyurethane or PIR polyiso foam, can be easily workable both in the factory and in the construction site, speeding up the exposure times. The foam with which they are made, already makes them perfectly insulated and water resistant, while the aluminium coating guarantees their steam resistance and an easy cleaning of the surfaces.