Definition : a cooling tower is a hot water network cooling system used, among others, in the air-conditioning installations.
It is not necessary to possess devices approved by the DGS ( General Direction of Health Services ) to operate the treatment of the cooling towers. Indeed, the water that circulates in this type of installation is considered as“used” water unfit for consummation and is thus submitted to norms that are much less strict. Besides, the use of the copper-silver ionization thanks to its biocide and anti-algae effects allows to reduce, perhaps to totally suppress the use of some chemical products difficult to manipulate, and that have negative effects on the installations.

The cooling towers are very common equipments and they have a high contamination rate risk; they must be supervised with the greatest care. It is needless to underline the fact that most mortal accidents stated in the media were provoked by contaminated cooling tower (the Axa building Tower in 1998, the one of the Montparnasse Tower in 1999, the one of a Mall in Rennes in 2000 and the one of the France Television building in 2001).                                   

It is important to notice that the responsibility of the owners of the these installations has recently been emphasized by the authorities.
It is necessary to possess the guide of good practice and the maintenance book of the cooling towers emitted by the ministry :
Guide des bonnes pratiques - Legionella et tours aéroréfrigérantes (juin 2001)
Le guide des bonnes pratiques (texte intégral)
Carnet de suivi du système de refroidissement

• See concerned Cooling-twers