Norseal NOR820 Drop Down Seal | Surface Mounted

Norseal Norsound 820 Acoustic Drop Seal

The Norseal NOR820 is a surface mounted automatic drop seal designed to be fitted at the bottom edge of timber or metal doors. It provides smoke and acoustic sealing without the need to remove material from the door, making it a practical seal for retrofitting.

Key Product Features:

• Norsound NOR820
• Surface mounted automatic drop seal
• Install on the bottom edge of acoustic timber or metal doorsets
• For single action doors
• Available in a range of sizes
• Screw fix to door face
• No need to remove timber from the door
• Aluminium body with PVC gasket
• Satin silver finish with grey gasket
• Gap coverage: Up to 12mm
• Meets the smoke requirements of BS 8214
• Acoustically tested in accordance with BS EN ISO 10140-2
• Certifire Approved CF629
• 35dB rating*
• 125mm cutback (130mm for 400mm length only)
• Body dimensions: 44mm x 13.5mm (select length)

*The decible rating that the NOR820 drop down seals can achieve depends on the door manufacturer's test evidence for each specific door.

Norseal 820 Surface Mounted Drop Seal

The NOR820 drop seal is suited to applications where morticing the door is not practical or may affect compliance. It is face fixed to the door, so there is no need to machine the door leaf or remove core material.

This makes it a practical option for existing and pre-finished doors where the original construction needs to be maintained. It allows threshold sealing to be added without altering the door, while still supporting acoustic and smoke performance.

Once installed, the Norsound NOR820 activates automatically as the door closes. The gasket lowers onto the threshold to seal the gap, then lifts clear when the door opens for smooth operation.

Norseal Acoustic Seal with Tested Performance

The Norseal NOR820 door seal has been tested for acoustic performance to BS EN ISO 10140-2 and meets smoke requirements in line with BS 8214. It is also Certifire Approved.

This supports its use on internal doors, where controlling sound transfer and limiting smoke leakage at the threshold are both important. It is commonly used on doors within offices, corridors, accommodation, healthcare, and education environments where consistent door performance is expected.

The ability to improve sealing without altering the door construction is a key advantage.

Getting The Right NOR820 for Your Door

The Norseal 820 is available in a range of lengths to suit different door widths and can be cut to size during installation. 

The maximum cutback depends on the selected seal length and can be up to 125mm, although the 400mm length can be cut up to 130mm. The datasheet and installation instructions provide further information and can be downloaded from the Product Document section.

The wider Norseal drop seal range gives you flexibility depending on the installation method. Where a concealed solution is preferred, the NOR810 provides a rebated option. 

You can also explore our wider range of acoustic door seals and fire door ironmongery to support door performance across your facility.