Abstract: The module (2) comprises a tubular body (8) extending along a first axis (10) with at least one radial outlet (12). The module (2) has a female end-piece (16) at one extremity and a corresponding male end-piece (14) at the other. Bore holes (22, 28) extending along a plane which is substantially perpendicular to the first axis are provided on both sides of the module (2) at each of the ends thereof. When two modules (2) are fitted into each other, the bore holes (22) of one module are aligned with the bore holes (28) of the other module on both sides of the unit thus created. When the bore holes are parallel, adjacent modules are fixed by means of a U-shaped bracket whereby the branches thereof are placed in the aligned bore holes.