The 30,5 mm thickness of the foam and the 200 ?m of the external aluminium impart to this panel special resistance to atmospheric agents and to shocks. This, together with the internal smooth aluminium coating and the antimicrobial treatment make this panel suitable for the construction of ducts to be fitted outdoors at the service of rooms where a high level of hygiene is required. It should be used in conjunction with the waterproofing sheath Gum Skin.