Norsound NOR810S Automatic Drop Seal – 12 × 20mm is a compact, mortised door-bottom seal designed for installation into the bottom edge of acoustic timber doorsets.
The slim aluminium profile is rebated into the door leaf and secured using two fixing screws. When the door closes, a single mechanical actuator lowers the grey TPE gasket onto the floor, sill or threshold plate.
As the door opens, the gasket retracts into the aluminium housing, helping maintain floor clearance and preventing the seal from dragging continuously across the finished surface.
The NOR810S is particularly suitable where the larger 14 × 35mm NOR810 profile cannot be accommodated within the door construction.
The NOR810S is designed to treat the otherwise open gap beneath a timber door.
An untreated threshold gap can allow:
The automatic gasket lowers only when the door closes, providing a practical alternative to a permanently exposed door-bottom seal.
The NOR810S contains a mechanically operated internal drop mechanism.
An adjustable actuator is positioned at the hinge side of the door. As the door reaches its closed position, the actuator contacts the frame and activates the mechanism.
The grey TPE gasket then lowers towards the floor or threshold.
When the door opens, pressure is released from the actuator and the gasket retracts into the aluminium housing.
The product requires:
The NOR810S has a nominal profile size of:
This smaller profile requires a significantly shallower mortise than the standard NOR810, which measures 14 × 35mm.
The reduced dimensions can make the NOR810S suitable for doors where:
The door must still have sufficient structural material to receive the 12 × 20mm routed groove.
The NOR810S can cover a threshold gap of up to 12mm.
The seal should be adjusted so that the gasket makes light and continuous contact with the finished floor or threshold when the door is fully closed.
The gasket should not be forced down further than necessary.
Excessive actuator travel can:
Where the threshold gap exceeds 12mm, a different drop seal or a revised threshold arrangement may be required.
Norseal specifies the NOR810S for the bottom edge of acoustic timber doorsets.
The gasket helps reduce sound leakage by closing the air path beneath the door when it is shut.
The individual drop seal does not have a universal standalone decibel rating.
Final sound reduction depends on the complete door assembly, including:
For effective acoustic performance, the entire perimeter of the doorset should be sealed rather than treating only the bottom edge.
Norseal states that the NOR810S meets the smoke requirements of BS 8214 within suitable doorset arrangements.
When correctly installed and adjusted, the TPE gasket helps restrict smoke passing through the gap beneath the closed door.
The drop seal must be used alongside the other smoke-control components required by the doorset, which may include:
The threshold surface must allow the gasket to make continuous contact across the complete width of the door.
Norseal states that the NOR810S is suitable for use on most fire doors.
This does not give the individual seal a standalone fire-resistance rating.
Before routing a fire-resisting door, confirm:
Machining an unverified fire door can invalidate the certification, assessment or warranty applying to the doorset.
The NOR810S is mortised into a routed groove along the bottom edge of the door.
Unlike the larger NOR810, which is retained primarily through its end components, the NOR810S is secured using two fixing screws.
The manufacturer’s fitting arrangement includes:
The end cap is fitted at the non-hinge side after the seal has been inserted and screw-fixed.
The NOR810S uses one adjustable actuator.
The actuator is positioned at the hinge side and operates as the door closes against the frame.
The amount of gasket travel can be altered using a screwdriver:
The mechanism can also be deactivated by removing the actuator, although this prevents the seal from lowering and therefore removes its threshold-sealing function.
The flexible gasket is manufactured from grey TPE.
TPE, or thermoplastic elastomer, combines flexible sealing behaviour with the processing characteristics of a thermoplastic material.
The gasket provides:
The gasket should be kept free from:
The internal mechanism is contained within a mill-finish aluminium profile.
The aluminium housing provides:
Once fitted, most of the aluminium housing is concealed within the bottom edge of the door.
The NOR810S can close against a suitable:
A threshold plate may be beneficial where the existing floor is:
The actuator should be adjusted only after the final floor or threshold surface has been completed.
The NOR810S is available in the following standard lengths:
The closest suitable length should be selected according to the measured width of the door and the permitted cut-back.
Most NOR810S lengths can be shortened by up to 150mm.
The shorter models have reduced cut-back allowances:
The exact limit shown on the individual product label must always be checked before cutting.
Cutting beyond the permitted limit can damage the internal mechanism and prevent the seal from operating.
The NOR810S has a profile size of 12 × 20mm and covers gaps of up to 12mm.
The NOR810S+ is a separate, deeper product with a nominal profile size of 12 × 30mm.
The two products should not be treated as interchangeable.
Select the correct version according to:
The standard NOR810 measures 14 × 35mm and can cover larger threshold gaps of up to 20mm.
The NOR810S is more compact at 12 × 20mm and covers gaps of up to 12mm.
Choose the version permitted by the doorset evidence and suitable for the door construction.
The NOR810S can be used within appropriate doorsets in:
Before ordering, confirm:
Do not machine a fire-rated, hollow-core, glazed or specialist door until the proposed installation has been checked against the applicable doorset documentation.
Norsound NOR810S Automatic Drop Seal is a compact, rebated and screw-fixed automatic door-bottom seal with a mill-finish aluminium housing, grey TPE gasket and single mechanical actuator.
| Product Name | Norsound NOR810S Automatic Drop Seal – 12 × 20mm |
| Brand | Norsound by Norseal |
| Product Reference | NOR810S |
| Product Type | Compact rebated automatic acoustic and smoke door-bottom seal |
| Application | Bottom edge of acoustic timber doorsets |
| Installation Method | Mortised into the bottom edge of the door and screw-fixed |
| Profile Width | 12mm |
| Profile Depth | 20mm |
| Maximum Gap Coverage | 12mm |
| Actuation | Single mechanical actuator |
| Actuator Position | Hinge side of the door |
| Actuator Adjustment | Adjustable using a screwdriver |
| Adjustment Direction | Clockwise reduces the drop distance; anti-clockwise increases the drop distance |
| Deactivation | The mechanism can be deactivated by removing the actuator |
| Power Requirement | None — mechanically operated |
| Housing Material | Aluminium |
| Housing Finish | Mill finish |
| Gasket Material | TPE |
| Gasket Colour | Grey |
| Smoke Performance | Meets the smoke requirements of BS 8214 within appropriate doorset arrangements |
| Fire-Door Application | Suitable for use on most fire doors, subject to the complete doorset evidence |
| Standard Lengths | 325, 425, 525, 625, 725, 825, 925, 1025, 1125 and 1225mm |
| Maximum Standard Length | 1225mm |
| General Cut-Back | Up to 150mm |
| 425mm Cut-Back | Maximum 140mm |
| 325mm Cut-Back | Maximum 40mm |
| Approximate Minimum Finished Length | 285mm when shortening the 325mm version by its maximum stated 40mm |
| Fixings Supplied | Two fixing screws |
| End Component | One push-fit end cap for the non-hinge side |
| Standalone Acoustic Rating? | No universal rating is stated for the individual seal; performance depends on the complete door assembly |
| Standalone Fire Rating? | No — fire performance depends on the complete tested or assessed doorset |
| Length | Profile Size | Finish | Maximum Cut-Back | Product Code |
|---|---|---|---|---|
| 325mm | 12 × 20mm | Mill finish / Grey gasket | 40mm | NOR810S/0325 |
| 425mm | 12 × 20mm | Mill finish / Grey gasket | 140mm | NOR810S/0425 |
| 525mm | 12 × 20mm | Mill finish / Grey gasket | 150mm | NOR810S/0525 |
| 625mm | 12 × 20mm | Mill finish / Grey gasket | 150mm | NOR810S/0625 |
| 725mm | 12 × 20mm | Mill finish / Grey gasket | 150mm | NOR810S/0725 |
| 825mm | 12 × 20mm | Mill finish / Grey gasket | 150mm | NOR810S/0825 |
| 925mm | 12 × 20mm | Mill finish / Grey gasket | 150mm | NOR810S/0925 |
| 1025mm | 12 × 20mm | Mill finish / Grey gasket | 150mm | NOR810S/1025 |
| 1125mm | 12 × 20mm | Mill finish / Grey gasket | 150mm | NOR810S/1125 |
| 1225mm | 12 × 20mm | Mill finish / Grey gasket | 150mm | NOR810S/1225 |
Norseal’s general manufacturer order-code format is:
NOR810S + supplied length
For example:
The slash-separated product codes in the table above are the codes used within the current supplied product range.
Choose a supplied seal that is longer than the required finished length but remains within its permitted cut-back.
| Supplied Length | Maximum Cut-Back | Approximate Minimum Finished Length |
|---|---|---|
| 325mm | 40mm | 285mm |
| 425mm | 140mm | 285mm |
| 525mm | 150mm | 375mm |
| 625mm | 150mm | 475mm |
| 725mm | 150mm | 575mm |
| 825mm | 150mm | 675mm |
| 925mm | 150mm | 775mm |
| 1025mm | 150mm | 875mm |
| 1125mm | 150mm | 975mm |
| 1225mm | 150mm | 1075mm |
The approximate minimum finished lengths are calculated from the manufacturer’s maximum cut-back figures. Always follow the cut-back value printed on the individual product label.
The NOR810S is designed for the bottom edge of acoustic timber doorsets.
No universal standalone decibel rating should be assigned to the individual seal.
Final sound reduction depends on:
The NOR810S meets the smoke requirements of BS 8214 within suitable complete doorset arrangements.
The grey TPE gasket must make continuous contact with the finished floor, sill or threshold when the door is closed.
A suitable smoke-sealing system will also normally be required around the door head and jambs.
Norseal states that the NOR810S is suitable for use on most fire doors.
This does not provide a standalone fire rating.
Before installation:
The NOR810S can close against a suitable floor, sill or threshold plate.
A threshold plate may improve sealing where the existing floor is:
The actuator should be adjusted after the final threshold surface has been completed.
Store the NOR810S:
Do not allow debris to enter the internal drop mechanism.
Norsound NOR810S Automatic Drop Seal is installed into a 12mm-wide × 20mm-deep routed groove along the full width of the bottom edge of a suitable timber door leaf.
The seal is cut to approximately 3mm less than the measured door width, inserted into the groove and secured using the two supplied fixing screws.
The actuator must be positioned at the hinge side, with the push-fit end cap installed at the non-hinge side.
Inspect the door, frame and threshold.
Confirm that:
Do not machine a fire-rated, hollow-core, glazed or specialist door without confirming that the installation is permitted.
Confirm that the package contains:
Identify:
Do not begin cutting until the permitted cut-back has been checked.
The maximum permitted cut-back depends on the supplied length:
The product label takes priority where it states a different or more restrictive limit.
Cutting beyond the permitted point may damage the internal mechanism.
Remove the door from its hinges where necessary.
Lay the door securely on its side and restrain it firmly.
Support the complete length of the door to avoid twisting or damage while routing.
Protect:
Measure the width of the door along its bottom edge.
Record this measurement as L.
Measure at the exact position where the drop seal will be installed rather than assuming the door is perfectly square.
Mark a straight groove along the complete width of the door bottom.
The required mortise is:
Check that sufficient door material will remain on both faces after the groove has been routed.
Use a router, 12mm cutter and suitable guide to machine the groove.
Remove the timber in controlled passes rather than attempting the full 20mm depth in one operation.
Maintain:
Avoid cutting into structural rails, glazing systems, fixings or other door components.
Remove all timber dust, chips and loose fibres.
Use a brush or vacuum to clear the mortise.
Check that:
The manufacturer’s fitting guide instructs the seal to be cut to:
L − 3mm
Measure from the actuator end and mark the aluminium housing at the calculated length.
For example:
Confirm that the required cut remains within the permitted cut-back limit.
The measurement is taken from the actuator end.
The excess material should therefore be removed from the opposite, non-actuator end.
Before cutting, reconfirm:
Do not shorten the actuator end.
Partially remove or slide the flexible gasket away from the cutting line.
Move enough gasket clear of the saw to prevent accidental damage.
Do not:
Support the seal securely and cut the aluminium housing squarely at the marked position.
Use a suitable fine-tooth saw.
After cutting:
Return the TPE gasket to its natural position within the housing.
Trim it cleanly to the finished length.
Do not stretch the gasket while measuring or cutting, as it may retract and finish too short.
Check that the gasket remains:
Place the NOR810S into the routed groove.
Position the actuator at the hinge side of the door.
Check that:
Mark and drill suitable pilot holes where required.
Secure the drop seal using the two fixing screws supplied.
Tighten the screws evenly.
Do not overtighten them, as this may:
Push the supplied end cap into place at the non-hinge side of the seal.
Check that the end cap is fully seated and does not interfere with the gasket or internal mechanism.
Return the door to its frame and secure it correctly to the hinges.
Check that:
Close the door slowly while observing the gasket.
The seal should:
Use a screwdriver to adjust the actuator.
Make small adjustments:
Close and open the door after every adjustment.
Continue until the gasket touches the floor or threshold without being compressed excessively.
Close the door and inspect the complete gasket.
Confirm that:
Where the floor is uneven or compressible, install a suitable threshold plate instead of over-adjusting the drop seal.
Operate the door several times.
Confirm that:
The manufacturer states that the NOR810S can be deactivated completely by removing the actuator.
When the actuator is removed, the gasket will not lower automatically.
Deactivation therefore removes the acoustic and smoke-sealing function at the threshold and should not be used where the operating seal is required by the doorset specification.
Where a threshold plate is required, fit and secure it before completing the final actuator adjustment.
The threshold plate should:
Readjust the NOR810S after the final threshold has been installed.
The NOR810S treats only the gap beneath the door.
Suitable perimeter seals will normally also be required around the:
Use the complete sealing arrangement specified by the applicable acoustic, smoke or fire doorset evidence.
Inspect and operate the NOR810S regularly as part of the door-maintenance programme.
Check for:
Clean the gasket and threshold using a soft cloth and a suitable mild cleaning product.
Do not apply unapproved oil, grease or lubricant to the internal mechanism.
Correct machining, cutting, fixing and actuator adjustment are essential to the operation of the NOR810S.
The product does not independently create an acoustically rated, smoke-control or fire-resisting door.
Final performance depends on:
For certified doorsets, install the NOR810S only in accordance with the applicable test evidence, assessment, certification and door-manufacturer instructions.
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