Concepts and translations

What is a multinetwork gallery ?

The Clé de Sol guidebook, published by TechniCités, means by the term « multinetwork gallery» a set of networks grouped together in the same physical space. This space is, as a rule, accessible, so that the networks that it contains may be more easily observed, managed and maintained.

A set of networks devised in this manner often necessitates the building of a housing. This leads to frequent confusion of terminology, the word "gallery" being used for the housing alone. Clé de Sol recommends that users avoid this ambiguity by complying with the following definitions

•"gallery", the structure as a whole, networks included, in other words the totality "container plus contents",
•"housing", the casing inside which the networks are contained, in other words the "container".
It should also be noted that the building of a complete housing is not always necessary, when it is possible to make use of pre-existing spaces or of spaces created for other purposes (constructions over flagstones, car parks, empty spaces beneath buildings, subways etc.).

Two complementary concepts

The two concepts, which make up the multinetwork gallery, are thus:
The group of networks (more and more often called the "colocation") which allows economies of space in an area that is increasingly sought after, the urban underground, and the sharing of numerous expenses
The physically existing shared space which makes it possible to see, observe and quickly reach the networks and, therefore, to check and maintain them in the best possible technical, legal and financial conditions.

Vocabulary and translations

In France, thirty years ago, only the term « galerie technique » was used. Although still in use, this expression seems to be losing ground to « galerie multiréseaux », which is more precise.
Belgians often use the term « caniveau technique » to mean « galerie multiréseaux ». Care must be taken because, in France, this expression means something different: the embedding of the networks in accessible space beneath the pavement/sidewalk made possible by detachable flagstones. Although this system possesses some of the advantages of the gallery as the French understand it, there is nonetheless the drawback of not being able to see and maintain the networks directly without the intervention of a roadworks team. As well as this, wiring connections and crossing over of networks, which require space, are difficult in these conditions.
In the French-speaking areas of Switzerland, the expression « galerie technique » is still preferred.
In the English-speaking countries, various expressions are used: « multipurpose tunnel(s) », « multipurpose gallery(ies) », « utility tunnel(s) », « common utility duct », « common duct » or even more simply « gallery(ies) ». A new word seems to be having some success : « utilidor(s) », a contraction of « utility corridor(s) ».
Spanish speakers use the term « galeria(s) de servicios », and German speakers that of « Infrastrukturkanal(äle) » or « Leistungkanal(äle) ». This latter expression seems however somewhat ambiguous in German as it brings to mind electricity rather than other fluids.