Pyroplex Rigid Box Fire Only Intumescent Seal is a rigid-cased intumescent strip designed to support the fire resistance of suitable timber doorsets.
Installed into a routed groove around the edges of a timber door leaf or within the corresponding door frame, the seal remains inactive during normal use. When exposed to the elevated temperatures generated by a fire, its graphite-based intumescent material expands to help close the gap between the door and frame.
This helps maintain the integrity and insulation performance of the complete tested fire-resisting doorset.
Each strip is supplied in a fixed 2100mm length and is available from this product listing in:
Available colours are:
An intumescent seal is a passive fire-protection component fitted around the perimeter of a fire-resisting door.
Under everyday conditions, the Pyroplex strip sits discreetly within its routed rebate and does not need to be compressed against the opposing surface.
During a fire, the active graphite material reacts to heat and expands. This expansion helps fill the gap between the door leaf and frame, reducing the passage of flames and hot gases through the perimeter of the doorset.
The intumescent strip forms only one part of the complete fire-door assembly.
Fire performance also depends on:
This product is the fire-only version of the Pyroplex Rigid Box range.
It does not contain:
It is intended to provide intumescent fire protection within a suitable tested doorset.
Where cold-smoke or acoustic containment is also required, use a separately specified fire-and-smoke seal, such as an approved pile or flipper product covered by the relevant doorset evidence.
The active element contains expandable graphite held within a durable polymer.
When the surrounding temperature rises sufficiently, the graphite expands in multiple directions. The resulting intumescent material helps close the gap between the door leaf and frame.
This action supports the fire-resisting performance of the doorset by helping to:
The strip must be installed in the correct size, location and configuration to reproduce the tested arrangement.
The complete Pyroplex fire-only Rigid Box range includes products for 30-, 60-, 90- and 120-minute systems.
The sizes available from this particular product listing cover appropriate 30- and 60-minute timber doorset arrangements:
These classifications apply to complete tested or assessed door constructions.
A strip does not independently provide a 30- or 60-minute fire rating, and fitting a particular width will not automatically convert an ordinary door into a fire door.
Pyroplex lists primary evidence for the 15 × 4mm profile in both 30- and 60-minute systems.
Whether it is suitable for a particular door depends on the complete doorset construction, including:
The required profile must therefore be confirmed from the door manufacturer’s certificate, data sheet, assessment or installation instructions.
The intumescent material is contained within a rigid PVC-u outer casing.
The casing helps:
The rigid profile is approximately 4mm deep across the stocked size options.
The rear of the seal is supplied with a high-performance acrylic self-adhesive backing.
Once a correctly sized groove has been routed and cleaned, the release liner is removed and the strip is pushed firmly into position.
The seal is installed as a self-adhesive friction fit and does not normally require visible screws.
For optimum adhesion, the rebate must be:
Pyroplex specifies an application temperature between +5°C and +40°C.
The Pyroplex Rigid Box Fire Only Seal is designed for installation into rebates in:
It can be used within suitable:
The exact position and number of seals must match the tested or assessed doorset arrangement.
Typical applications can include suitable fire-resisting timber doorsets in:
This fire-only product does not include a brush pile, flexible fin or flipper for controlling cold smoke during normal temperatures.
Although the intumescent material expands during a fire, it should not be sold as a cold-smoke seal.
Where the fire-door specification requires smoke control, select a suitable fire-and-smoke product covered by the relevant doorset evidence.
The gap beneath the door may also require a tested automatic drop seal or another approved threshold-sealing arrangement.
No standalone acoustic performance is stated for the fire-only Rigid Box strip.
Because it does not include a pile or flexible gasket, it is not intended to close normal operating gaps for acoustic containment.
Where acoustic performance is required, the complete door assembly will normally need:
Select the seal using the evidence for the complete door rather than the nominal fire period alone.
Before ordering, confirm:
Do not assume that a wider strip necessarily provides greater fire resistance.
This product is available in four stocked casing colours:
Colour selection affects the appearance of the casing but does not change the required fire-door specification.
Each variation is supplied as one 2100mm length.
The length can be cut on site to suit the approved position around the door leaf or frame.
More than one length will normally be required to seal a complete doorset. The quantity depends on:
Before purchasing, check the fire-door certificate, assessment or manufacturer’s instructions.
Do not substitute:
Unauthorised substitutions may invalidate the tested fire performance of the complete doorset.
Pyroplex Rigid Box Fire Only Intumescent Seal is a self-adhesive, rigid-cased graphite intumescent strip for use within suitable fire-resisting timber doorsets.
| Product Name | Pyroplex Rigid Box Fire Only Intumescent Seal |
| Manufacturer | Pyroplex |
| Product Range | Rigid Box Fire Only |
| Product Type | Rigid-cased graphite intumescent fire-door strip |
| Application | Edges and frames of suitable fire-resisting timber doorsets |
| Primary Function | Intumescent fire sealing |
| Cold-Smoke Seal | No — this product does not contain an integral pile, fin or flipper |
| Acoustic Seal | No standalone acoustic sealing function is stated |
| Active Material | High-pressure-forming, multidirectionally expandable graphite contained within a durable polymer |
| Outer Casing | Approximately 0.5mm PVC-u rigid casing |
| Fixing | Acrylic self-adhesive backing and friction fit within a routed groove |
| Standard Length | 2100mm |
| Available Sizes | 10 × 4mm, 15 × 4mm and 20 × 4mm |
| Available Colours | Black, Brown, Grey and White |
| Installation Position | Centrally within the timber door-leaf edge or frame unless the doorset evidence specifies otherwise |
| Suitable Door Actions | Single and double action |
| Suitable Door Configurations | Single- and double-leaf doorsets |
| Latch Configurations | Latched and unlatched doors, subject to supporting evidence |
| Application Type | New-build and suitable retrofit applications |
| Fire-Resistance Systems Covered by Available Sizes | 30 and 60 minutes within appropriate tested or assessed doorsets |
| Fire Test Standards | BS 476: Part 20/22, BS EN 1634-1 and BS EN 1363-1 |
| Certifire Approval | Certificate CF355 |
| Certifire Technical Schedule | TS35; current Pyroplex product information also references TS21 |
| International Standard Referenced | UL10C |
| Recommended Application Temperature | +5°C to +40°C |
| Maximum Recommended Storage Temperature | +35°C |
| Published Life Cycle | 10 years when installed in accordance with Pyroplex guidance |
| Product Guarantee | 10 years when correctly installed in accordance with the manufacturer’s guidance |
| Traceability | Unique product identification is provided |
| Standalone Fire Rating? | No — performance depends on the complete tested or assessed doorset construction |
| Size | Length | 30-Minute Evidence | 60-Minute Evidence |
|---|---|---|---|
| 10 × 4mm | 2100mm | Yes | No primary evidence listed |
| 15 × 4mm | 2100mm | Yes | Yes |
| 20 × 4mm | 2100mm | No primary evidence listed | Yes |
| Size | Colour | Product Code |
|---|---|---|
| 10 × 4mm | Black | 104FO/2100/BLK |
| 10 × 4mm | Brown | 104FO/2100/BRN |
| 10 × 4mm | Grey | 104FO/2100/GRY |
| 10 × 4mm | White | 104FO/2100/WHT |
| 15 × 4mm | Black | 154FO/2100/BLK |
| 15 × 4mm | Brown | 154FO/2100/BRN |
| 15 × 4mm | Grey | 154FO/2100/GRY |
| 15 × 4mm | White | 154FO/2100/WHT |
| 20 × 4mm | Black | 204FO/2100/BLK |
| 20 × 4mm | Brown | 204FO/2100/BRN |
| 20 × 4mm | Grey | 204FO/2100/GRY |
| 20 × 4mm | White | 204FO/2100/WHT |
Pyroplex’s wider fire-only Rigid Box range also includes additional profiles for project-specific doorset arrangements.
These include:
These additional sizes are not included within the current stocked product range.
The appropriate profile must be selected from the evidence for the complete fire doorset.
Relevant factors include:
The stated 30- and 60-minute applications refer to complete tested doorset configurations.
They do not represent independent ratings for an individual strip.
In particular:
This product does not contain a brush pile, flexible fin or flipper.
It should not be described as:
Where these functions are required, use the specified Pyroplex fire-and-smoke product or another approved system covered by the door evidence.
Store the seals:
Inspect the installed seals regularly as part of the fire-door inspection programme.
Replace the correct specified component where the seal is:
Do not replace a damaged strip with a different profile or type without confirming compatibility with the doorset evidence.
Pyroplex Rigid Box Fire Only Intumescent Seal is installed into a correctly sized routed groove in either the edge of a timber door leaf or the timber door frame.
The selected size, number of seal lines and installation position must match the test evidence, assessment or certification for the complete fire-resisting doorset.
Confirm the complete fire-door specification before machining the door or frame.
Check:
Do not assume that every door with the same nominal fire rating uses the same seal size or arrangement.
Inspect the complete doorset before installation.
Confirm that:
Significant defects should be rectified before the seal is installed.
Pyroplex’s general installation guidance states that the seal should be located centrally within either the door-leaf edge or the frame.
Mark the centre line in the position required by the doorset evidence.
Where two lines of intumescent material are specified, mark both grooves accurately and maintain the required spacing.
Do not reposition the seal merely to avoid hinges or other hardware unless the alternative arrangement is supported by the applicable evidence.
Measure each section individually.
For a typical single-leaf doorset, this can include:
Double doors may require additional seals at the meeting stiles, depending on the tested arrangement.
Do not assume that both jambs or leaves are identical in length.
Transfer each measurement onto the relevant 2100mm length.
Keep the self-adhesive release liner attached while measuring and cutting.
Cut the rigid profile using a fine-tooth saw or another suitable cutting tool.
Support the strip during cutting to prevent:
After cutting:
Use a router cutter corresponding to the nominal width of the selected strip:
Set the groove depth to accommodate the nominal 4mm profile and the requirements of the doorset specification.
Where practical, test the router setting on a suitable timber offcut before machining the door or frame.
Route a straight and continuous groove in the specified position.
Use a router guide or fence to maintain consistent alignment.
Work carefully to avoid:
The finished groove should hold the rigid strip firmly without crushing or distorting the casing.
The treatment of intumescent seals around hinges, locks, latches, closers and other hardware must follow the doorset evidence.
Do not remove large sections of the seal simply to clear ironmongery.
The tested specification may require:
Unauthorised interruptions may compromise the fire resistance of the complete doorset.
Remove all timber dust, fibres and loose debris from the groove.
Use a brush, vacuum and clean dry cloth as required.
The rebate should be:
Dust or contamination can reduce the adhesion of the acrylic backing.
Pyroplex specifies an installation temperature between:
+5°C and +40°C
Do not apply the strip to a wet, frozen or excessively hot substrate.
Allow cold products, doors and frames to reach an appropriate installation temperature before removing the release liner.
Place the cut strip into the groove before exposing the adhesive.
Check that:
Remove the dry-fitted strip carefully.
Peel the protective liner from the acrylic self-adhesive backing.
Avoid touching or contaminating the exposed adhesive.
Remove the liner progressively as the strip is installed rather than exposing several full lengths at the same time.
Align the rigid profile with the routed groove and push it firmly into place.
Work progressively along the complete length while maintaining alignment.
Press the profile firmly against the base of the rebate to create consistent adhesive contact.
Do not:
Repeat the process for every head, jamb and meeting-stile section required by the doorset specification.
At joints:
Inspect the installed seal around the full perimeter.
Confirm that:
Open and close the door several times.
Confirm that:
Because the product does not include a pile or flipper, it does not need to compress against the opposing surface during normal door operation.
This product provides fire-only intumescent sealing.
Where the doorset must restrict cold smoke, confirm that a compatible smoke-sealing component has also been installed.
Depending on the tested arrangement, this may include:
Do not assume that the fire-only strip satisfies a smoke-control specification.
Inspect the intumescent seals regularly as part of the fire-door inspection and maintenance programme.
Check for:
Replace damaged components using the exact specified product, size and type.
Do not substitute a pile, flipper or differently sized strip without confirming that it is permitted by the doorset evidence.
Before installation, store the strips:
The Pyroplex Rigid Box Fire Only Intumescent Seal is one component within a complete fire-resisting doorset.
It does not independently create a 30- or 60-minute fire door.
Final performance depends on:
Always install the seal in accordance with the current doorset evidence, Pyroplex technical guidance and project fire-door specification.
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