Construction in fully galvanized corrugated steel plate, assembled by means of galvanized bolting and reinforced by outside stiffeners (depending of the height).
128 models :
- 20 diameters from 1.78m àto 15.10m
- 16 highs from 0.90m to 13.44m
Ventilation netwoks :
- by perforated ducts
- by ventilation channels in concrete base (flat or conical)
- by vented steel cone
- by 'venticloche'