Principally

Principally designed for our natural ventilation range, our plastic volume control dampers have a shut off level far surpassing that of regular volume control dampers and even some shut off dampers.
Independent tests show no leakage below 10Pa; the pressure most likely to be found in natural ventilation installations.
With even 10Pa rarely being exceeded in natural ventilation situations, it is clear how uPVC volume control dampers can enhance the efficiency of your new natural ventilation system.