Pre-insulated double wall spiral ducts and fittings are used for external applications and in places where it is impossible to insulate spiral ducts with an aluminium jacket. All inner duct fittings are equipped with an EPDM gasket providing the ventilation system with the airtightness class D.
The inner and outer duct is made of sheet metal and the spiral duct diameters – between which a mineral wool is placed. Duct insulation has thickness from 25 to 100mm, for marine applications there is available pre insulated ventilation system with non-combustible insulation in 10 and 16mm thickness.
Pre-insulated spiral ductwork is availabe in diamter ranging from 080 mm to 1250 mm made of a galvanized, aluminium or stainless steel sheet. See special access doors for pre insulated spiral ducting - IPR-RRD-I. See also double wall spiral ducts for marine and offshore appliacations.