IRRD-DW2 Insulated Access Door Solution

Solution for double-wall round ducts with very thick insulation. 

For this solution two independent RRD access doors are combined (one for the inner duct and the second one, preferably larger, for the outer duct) depending on the circular double-skin duct characteristics and the insulation thicknesses.

Excellent insulating properties, since there are no thermal bridges.

Please observe the minimum insulation thicknesses below.

Availability and price upon request.

Minimum required insulation thicknesses:

IRRD-DW2 18: ≈ 42 mm
IRRD-DW2 21: ≈ 42 mm
IRRD-DW2 32: ≈ 55 mm
IRRD-DW2 43: ≈ 60 mm
IRRD-DW2 54: not feasible.


Using metal knobs in order to install the IRRD-DW2 access doors on a round ducts having thinner insulation thicknesses as the ones indicated above does not work, as the bolt lengths remain the same.


  1. Inner duct wall
  2. Outside duct wall or hard aluminum outer skin.
  3. Insulation thickness (please observe the minimum required insulation thicknesses)
  4. RRD access door
  5. Second RRD access door (can normally be made of the same material as the outer duct, liken in aluminum when the duct is covered with a hard aluminum skin).
  6. The air pocket trapped between the two access doors offers excellent insulating properties. To avoid any convection currents insulation chunks can be stuffed into the hollow spaces between the access doors.

Please refer to the RRD prices

RRD opening dimensions according to the duct-Ø


To be taken into consideration when fitting stainless steel parts


Made by METU in Germany