Only three dimensions: RD 18, RD 21, RD 32.
The reason why the NBR gasket is not offered for all the access door sizes has to do with the necessary pressure needed to make the connection door / airduct oil-tight. Indeed, the knobs of the larger access doors do not provide enough pressure on the NBR gasket along the entire circumference of the opening. As a result the NBR gasket is not sufficiently compressed and an oil-leakage may occur.
Only suitable for ducts with a clean and smooth surface without seams.
Properly installed access doors withstand positive or negative pressures up to at least ≈ 5000 Pa. (≈ 500 mm w.g.). Since the conditions on the construction site are never ideal, and because the quality of the ducts does vary, no definitive guarantees can be given regarding the tightness, especially in the long term.
Max. operating temperature: ≈ + 80°C.