Norsound's NOR720 is a small seal with an impressive dB reduction. Its placement in the door frame means it can easily be used in conjunction with the NOR710, achieving as high as a 48dB reduction in some configurations (please see the test evidence for further information).
This seal is only 5mm wide and once fitted only three thin 4.2mm long blades are visible, giving a discrete finish without compromising acoustic performance.
The NOR720 also has smoke seal capabilities in accordance with BS 476: Part 31: 1987 and its design is based on ‘dual air pocket technology‘ which acts in the same way as triple glazing. We have cycle tested the NOR 720 acoustic seal up to 100,000 opening and closing cycles.
The NOR 720 fits into a groove of 3mm wide by 4mm deep.
As this seal is so small and fits into a 3mm groove it can be positioned either side of most common ironmongery.
Since this seal is symmetrical it can be fitted to either the frame or the door leaf in either single or double rows.
No. Since the NOR 720 is a continuous acoustic seal it acts as a smoke seal, better in some ways than standard intumescent smoke seals.