Plenum boxes are employed in small systems as an alternative to distribution and/or sucking conduits, both for economical as well as overall dimensions reasons.

Plenum boxes, in fact, are directly insalled in the throwing and/or pickup salvages. A circular collare is installed in holes made in the boxes, and a flexable hose may be fastened to the collar by means of hose clampings.

Plenum boxes are realized in the following materials:

- galvanized steel (with or without insulation)

- stainless stell (with or without insulation)

- sandwich pannel