The "Legionary disease", a lung infection caused by "Legionella Pneumophila" has emphasized how much the quality of the air conditioned can be dangerous. This new pathological phenomenology has stressed not only the need of a constant control of the air conditioned quality but even the danger of new and/or dangerous lung infections cause by bacteria and fungi which find an easy habitat within the ducts and are blown out into the closed premises.

In the past years the traditional repair of old leaking drain pipes was involving major masonry works, installation of scaffolds, occupation of public pavements, production of noise and dust originating uneasiness for the inhabitants of the buildings and high costs of the repair operations.