Pyroplex Rigid Box Pile Fire and Smoke Seal
Pyroplex Rigid Box Pile Fire and Smoke Seal is a combined intumescent fire and smoke seal designed for installation around the edges and frames of fire-resisting timber doorsets.
The seal contains an intercalated graphite intumescent material within a rigid casing, together with an integral brush pile. Under normal conditions, the brush pile helps restrict the passage of cold smoke, draughts and sound through the gap between the door leaf and frame.
When exposed to fire, the intumescent material expands to help close the perimeter gap and support the fire-resisting performance of the complete doorset.
This product is supplied in a fixed 2100mm length and is available in:
- 10 × 4mm
- 15 × 4mm
- 20 × 4mm
Available casing colours are:
What is a fire and smoke seal?
A fire and smoke seal combines two complementary forms of door protection.
The intumescent section reacts when exposed to elevated temperatures. It expands to help fill the gap between the door leaf and frame, supporting the integrity of the fire-resisting doorset.
The projecting brush pile operates during normal conditions. It makes contact with the opposing door or frame surface to help restrict:
- Cold smoke
- Air movement
- Draughts
- Sound transmission through perimeter gaps
- Visible light around the closed door
The brush pile does not replace the intumescent material. Both components perform different functions within the complete door-sealing arrangement.
Where is the seal installed?
The Pyroplex Rigid Box Pile Seal is installed into a routed groove in either:
- The edges of a timber door leaf
- The head and jambs of a timber door frame
The precise position, size and quantity of seals must follow the specification or fire-test evidence for the complete doorset.
The seal is suitable for use with:
- Single-leaf doors
- Double-leaf doors
- Single-action doors
- Double-action doors
- Latched doors
- Unlatched doors
- New-build doorsets
- Suitable retrofit installations
Available fire-resistance options
The size required depends on the construction and certification of the fire doorset.
Within this product listing:
- 10 × 4mm — listed by Pyroplex for suitable 30-minute systems.
- 15 × 4mm — listed by Pyroplex for suitable 30-minute systems.
- 20 × 4mm — listed by Pyroplex for suitable 60-minute systems.
These designations do not mean that an individual strip independently provides 30 or 60 minutes of fire resistance.
The fire performance applies only when the specified seal is installed as part of an appropriate tested or assessed doorset construction.
Fire-test performance
The Pyroplex Rigid Box Pile range has been tested to recognised fire-resistance standards, including:
- BS 476: Part 20/22
- BS EN 1634-1
The product range is covered by Certifire Certificate CF355.
Before selecting a seal, always check the supporting evidence for the door. The required seal can vary according to:
- The door-leaf core
- The door thickness
- The frame construction
- The fire-resistance period
- The number and position of seal lines
- The door configuration
- The latch and ironmongery arrangement
Smoke-sealing performance
The integral brush pile helps restrict cold smoke leakage through the perimeter gap around a closed door.
The Pyroplex Pile range has smoke-test evidence to:
- BS 476: Part 31.1
- BS EN 1634-3
For effective smoke containment, the brush pile should make consistent contact around the head and jambs without preventing the door from closing or latching correctly.
The gap beneath the door may require a suitable smoke-rated automatic drop seal or threshold seal.
Acoustic sealing
The brush pile can also help reduce airborne sound passing through gaps between the door and frame.
The Pyroplex Pile range has been acoustically tested to BS EN ISO 10140-2.
The individual strip does not have a universal standalone decibel rating. Final sound reduction depends on the complete door assembly, including:
- The mass and construction of the door leaf
- The door frame
- The perimeter seals
- The gap beneath the door
- The threshold or automatic drop seal
- Glazing and ironmongery
- The frame-to-wall junction
- The quality of installation
Self-adhesive friction-fit installation
The seal is supplied with a self-adhesive backing and is installed as a friction fit within a correctly sized routed groove.
Once the groove has been prepared and cleaned, the protective liner is removed and the strip is pressed firmly into position.
The self-adhesive backing supports installation but should only be applied to a clean, dry and stable substrate.
Which size should I choose?
The correct size must be taken from the door manufacturer’s fire-test evidence, assessment or certification.
Do not select a seal solely because:
- The door is labelled FD30 or FD60
- The existing strip appears to be a similar width
- A wider seal appears to offer greater protection
- The seal physically fits the existing groove
Installing a different width, quantity or seal position may invalidate the fire performance of the doorset.
Available colours
This product listing is available in:
- Black — suitable for dark doors and frames.
- Brown — suitable for timber and brown finishes.
- Grey — suitable for grey or neutral doorsets.
- White — suitable for white-painted doors and frames.
The colour affects the visible appearance of the rigid casing. It does not change the required seal size or the fire-resistance specification.
Standard length
Each seal is supplied as one 2100mm length.
The strip can be cut on site to suit the door head, jambs or other approved positions.
Several lengths may be required to complete one doorset. The quantity will depend on:
- The dimensions of the door
- Whether the seal is installed in the leaf or frame
- Whether the door is single or double leaf
- Whether meeting-stile seals are required
- The number of seal lines specified
Typical applications
The Pyroplex Rigid Box Pile Fire and Smoke Seal can be used within suitable fire-resisting timber doorsets in:
- Apartment buildings
- Hotels and guest accommodation
- Schools and education buildings
- Hospitals and healthcare environments
- Offices and commercial buildings
- Care homes
- Public buildings
- Corridors and escape routes
- Compartment walls
- Acoustic door assemblies
Key benefits
- Combined fire and smoke protection — incorporates both intumescent material and an integral brush pile.
- Supports acoustic sealing — helps reduce sound transfer through perimeter gaps.
- 30- and 60-minute systems — available in sizes for different tested doorset arrangements.
- Self-adhesive backing — supports straightforward installation into a prepared groove.
- Rigid construction — protects the intumescent material and provides a neat visible finish.
- Intercalated graphite — expands when exposed to elevated temperatures.
- Integral brush pile — helps restrict cold smoke, draughts and sound.
- Four stocked colours — available in Black, Brown, Grey and White.
- Three stocked sizes — available in 10 × 4mm, 15 × 4mm and 20 × 4mm.
- 2100mm length — suitable for cutting to common door and frame dimensions.
- Single and double doors — suitable for multiple doorset configurations where supported by evidence.
- New-build and retrofit applications — suitable where the doorset construction permits installation.
- Certifire approved range — covered by Certifire Certificate CF355.
Important buying advice
Before ordering, confirm:
- The required seal size
- The required colour
- The number of 2100mm lengths needed
- The seal position within the door or frame
- The number of seal lines required
- The fire-resistance period
- The door-leaf and frame construction
- The smoke-control requirements
- The applicable door certificate or test evidence
Do not substitute a different size or type of intumescent seal without confirming that the change is permitted by the doorset evidence.
Pyroplex Rigid Box Pile Fire and Smoke Seal Technical Specifications
Pyroplex Rigid Box Pile Fire and Smoke Seal is a self-adhesive intumescent perimeter strip with an integral brush pile for suitable fire-resisting timber doorsets.
Product Specification
| Product Name |
Pyroplex Rigid Box Pile Fire and Smoke Seal |
| Manufacturer |
Pyroplex |
| Product Type |
Rigid-box intumescent fire and smoke seal with brush pile |
| Application |
Edges and frames of fire- and smoke-resisting timber doorsets |
| Functions |
Fire, cold-smoke and acoustic perimeter sealing |
| Intumescent Material |
Intercalated graphite |
| Smoke-Sealing Element |
Integral brush pile |
| Standard Length |
2100mm |
| Available Sizes in This Listing |
10 × 4mm, 15 × 4mm and 20 × 4mm |
| Available Colours in This Listing |
Black, Brown, Grey and White |
| Fixing Method |
Self-adhesive backing and friction fit within a routed groove |
| Installation Position |
Centrally located in the door-leaf edge or timber frame unless the doorset evidence states otherwise |
| Suitable Door Configurations |
Single and double action; single- and double-leaf doors |
| Latch Configurations |
Latched and unlatched doors, subject to supporting doorset evidence |
| Fire-Resistance Range |
30- and 60-minute systems within appropriate tested doorset constructions |
| Fire Test Standards |
BS 476: Part 20/22 and BS EN 1634-1 |
| Smoke Test Standards |
BS 476: Part 31.1 and BS EN 1634-3 |
| Acoustic Test Standard |
BS EN ISO 10140-2 |
| Certifire Certificate |
CF355 |
| Certifire Technical Schedules |
TS35 and TS21 |
| Standalone Fire Rating? |
No — fire performance depends on the complete tested or assessed doorset |
| Standalone Acoustic Rating? |
No — acoustic performance depends on the complete tested door and sealing system |
Available Size Options
| Size |
Standard Length |
Manufacturer’s Listed System |
Smoke Performance |
Acoustic Performance |
| 10 × 4mm |
2100mm |
Suitable 30-minute systems |
Yes |
Yes |
| 15 × 4mm |
2100mm |
Suitable 30-minute systems |
Yes |
Yes |
| 20 × 4mm |
2100mm |
Suitable 60-minute systems |
Yes |
Yes |
Variation SKUs
| Size |
Colour |
Variation SKU |
| 10 × 4mm |
Black |
104FS/2100/BLK |
| 10 × 4mm |
Brown |
104FS/2100/BRN |
| 10 × 4mm |
Grey |
104FS/2100/GRY |
| 10 × 4mm |
White |
104FS/2100/WHT |
| 15 × 4mm |
Black |
154FS/2100/BLK |
| 15 × 4mm |
Brown |
154FS/2100/BRN |
| 15 × 4mm |
Grey |
154FS/2100/GRY |
| 15 × 4mm |
White |
154FS/2100/WHT |
| 20 × 4mm |
Black |
204FS/2100/BLK |
| 20 × 4mm |
Brown |
204FS/2100/BRN |
| 20 × 4mm |
Grey |
204FS/2100/GRY |
| 20 × 4mm |
White |
204FS/2100/WHT |
Product Selection
The correct seal size must be confirmed using the test evidence or certification for the complete doorset.
Selection factors include:
- The required fire-resistance period
- The door-leaf core and thickness
- The frame material and density
- The permitted perimeter gap
- The required number of seal lines
- The position of the seals
- The door handing and action
- Whether the door is latched or unlatched
- The hinge, lock and latch specification
- The threshold-sealing arrangement
Fire Performance Note
The size-based 30- and 60-minute designations relate to tested doorset systems.
They must not be interpreted as universal standalone ratings.
A 10 × 4mm or 15 × 4mm strip does not automatically make every door an FD30 door. A 20 × 4mm strip does not automatically make every door an FD60 door.
Some doorsets may require:
- Two intumescent strips
- A particular position within the leaf or frame
- Additional intumescent protection around ironmongery
- A particular threshold-seal arrangement
- Specific door-leaf and frame materials
Smoke Performance Note
The integral pile is intended to restrict smoke leakage through the gap between the door and frame.
To operate correctly:
- The pile must face the opposing surface
- The door must close fully
- The brush must make consistent contact
- The perimeter gaps must remain within the doorset specification
- The threshold gap must be treated where required
Acoustic Performance Note
The product has acoustic test evidence as part of complete door systems, but no standalone decibel rating should be assigned to an individual length.
Final performance depends on the door leaf, perimeter gaps, threshold seal, glazing, ironmongery and installation quality.
Storage
Store the seals:
- Flat and fully supported
- In a clean and dry location
- Away from moisture and excessive heat
- With the brush pile protected from crushing
- With the adhesive release liner intact
- Protected from bending, twisting and impact damage
How to Install the Pyroplex Rigid Box Pile Fire and Smoke Seal
Pyroplex Rigid Box Pile Fire and Smoke Seal is installed into a correctly sized routed groove in either the edge of a timber door leaf or the timber door frame.
The size, quantity and position of the seal must match the test evidence, assessment or certification for the complete fire doorset.
What You’ll Need
- Pyroplex Rigid Box Pile Seal in the specified size and colour
- Applicable door-manufacturer or doorset evidence
- Tape measure
- Pencil or suitable marker
- Fine-tooth saw or suitable profile-cutting tool
- Router
- Router cutter matching the selected seal width
- Router guide or fence
- Sharp utility knife
- Brush or vacuum
- Clean, dry cloth
- Suitable door supports
- Safety glasses
- Hearing protection
- Suitable respiratory protection when routing timber
Before You Start
Check the fire-door specification before machining the door or frame.
Confirm:
- The required seal size
- The required seal position
- Whether the seal is fitted in the leaf or frame
- The number of seal lines required
- The required fire-resistance period
- The permitted perimeter gaps
- The door-leaf and frame construction
- Whether the door is single or double action
- Whether the door is latched or unlatched
- How the seal should be treated around hinges and other ironmongery
Do not assume that every FD30 or FD60 door uses the same intumescent-seal arrangement.
Step 1: Inspect the Doorset
Inspect the door leaf and frame before installation.
Check that:
- The door is not severely warped or damaged
- The frame is securely installed
- The door opens and closes correctly
- The latch engages correctly
- The perimeter gaps are suitable
- The proposed groove will not damage structural door components
- The installation position does not conflict with ironmongery
Significant defects should be corrected before the seal is installed.
Step 2: Mark the Seal Position
Unless the supporting evidence states otherwise, Pyroplex instructs that the seal should be located centrally in either the door leaf or frame.
Mark the centre line and complete groove position.
Where more than one line of seal is required, mark each groove using the spacing stated in the doorset specification.
Step 3: Measure the Required Lengths
Measure every section individually.
For a typical single-leaf doorset, this may include:
- The door head
- The hinge-side jamb
- The closing-side jamb
Double doors may also require seals at the meeting stiles.
Do not assume both jambs or leaves are identical in length.
Step 4: Cut the Seal
Transfer the measurements onto the 2100mm seal lengths.
Cut each rigid profile cleanly using a fine-tooth saw or suitable cutting tool.
Support the strip during cutting to avoid splitting or distorting the casing.
After cutting:
- Remove loose cutting debris
- Check that the rigid casing remains intact
- Check that the brush pile remains secure
- Trim loose pile fibres carefully where necessary
- Do not stretch the strip to make it fit
Step 5: Select the Router Cutter
Use a router cutter matching the nominal width of the selected profile:
- 10mm cutter for the 10 × 4mm seal
- 15mm cutter for the 15 × 4mm seal
- 20mm cutter for the 20 × 4mm seal
The groove depth should accommodate the nominal 4mm profile and match the requirements of the doorset evidence.
Test the router setting on a suitable offcut where practical.
Step 6: Route the Groove
Route a straight and continuous groove in the specified position.
Use a router guide or fence to maintain consistent alignment.
Machine the groove carefully to avoid:
- Creating an oversized rebate
- Splitting the timber
- Damaging the door edge
- Cutting into structural components
- Producing an uneven depth
The groove should hold the rigid profile firmly without crushing or distorting it.
Step 7: Treat Ironmongery Positions Correctly
The seal arrangement around hinges, locks, latches and other ironmongery must follow the supporting doorset evidence.
Do not cut away large sections simply to clear hardware.
The specification may require:
- The intumescent material to continue behind a hinge blade
- A controlled local interruption
- Intumescent hinge pads
- Lock or latch protection
- A different seal position around the hardware
Unauthorised interruptions can compromise the fire performance of the doorset.
Step 8: Clean the Groove
Remove all routing dust, timber fibres and loose debris.
The groove should be:
- Clean
- Dry
- Sound
- Free from grease and oil
- Free from loose paint or varnish
- Free from sanding and routing dust
Poor surface preparation may reduce the effectiveness of the self-adhesive backing.
Step 9: Check the Installation Temperature
Pyroplex states that the seals should be applied to clean, dry surfaces at temperatures between:
+5°C and +40°C
Do not install the product onto a wet, frozen or excessively hot substrate.
Step 10: Dry Fit the Seal
Place each cut section into the groove before removing the backing liner.
Check that:
- The profile fits the groove
- The strip sits straight
- The casing is not crushed
- The brush pile faces the opposing surface
- The cut length is correct
- The joints meet neatly
- The seal does not prevent the door from closing
Remove the dry-fitted strip carefully.
Step 11: Remove the Adhesive Liner
Peel the release liner from the 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 once.
Step 12: Push Fit the Seal
Align the strip with the routed groove and press it firmly into position.
Work progressively along the seal while maintaining alignment.
Press across the full length to create consistent contact between the adhesive and the base of the groove.
Do not:
- Stretch the strip
- Twist it into the groove
- Crush the brush pile
- Hammer it with a metal tool
- Leave sections projecting from the rebate
Step 13: Install the Remaining Sections
Repeat the process for each head, jamb or meeting-stile section required by the doorset specification.
At joints:
- Cut the profiles accurately
- Bring the ends together neatly
- Avoid large open gaps
- Do not overlap the rigid profiles
- Maintain brush-pile continuity where possible
Step 14: Check Brush Contact
Close the door and inspect the brush pile around the complete sealed perimeter.
The pile should make suitable contact with the opposing door or frame surface without creating excessive resistance.
Check the:
- Door head
- Hinge-side jamb
- Closing-side jamb
- Meeting stiles on double doors
A warped or incorrectly hung door should be repaired rather than relying on the brush pile to compensate for excessive variation.
Step 15: Check Door Operation
Open and close the door several times.
Confirm that:
- The door opens freely
- The door closes fully
- The latch engages correctly
- The self-closing device closes the door where fitted
- The seals remain firmly seated
- The brush pile remains continuous
- No profile projects from the groove
- The perimeter gaps remain within specification
Step 16: Check the Threshold Gap
The Rigid Box Pile Seal normally treats the head and jambs rather than the bottom of the door.
Where smoke or acoustic containment is required, inspect the threshold gap and install the specified:
- Automatic drop seal
- Door-bottom seal
- Threshold plate
- Alternative tested threshold arrangement
The selected threshold system must be compatible with the doorset evidence.
Installation Tips
- Check the doorset specification before selecting a size.
- Do not select a seal using the fire rating alone.
- Install centrally unless the evidence states otherwise.
- Use a router cutter matching the selected profile width.
- Maintain a consistent groove depth.
- Remove all routing dust before installation.
- Install only between +5°C and +40°C.
- Dry fit each length before removing the adhesive liner.
- Do not stretch or compress the profile.
- Keep joints neat and closely fitted.
- Do not obstruct the brush pile with paint or finishes.
- Do not alter the seal around ironmongery without supporting evidence.
- Check that the door continues to close and latch correctly.
- Treat the threshold gap where smoke or acoustic sealing is required.
Maintenance Advice
Inspect the seals regularly as part of the fire-door inspection and maintenance programme.
Check for:
- Missing sections
- Loose or raised profiles
- Cracked or damaged casing
- Crushed or missing brush pile
- Contamination affecting brush contact
- Paint covering the seal
- Open joints between lengths
- Damage around hinges and locks
- Changes in the door-to-frame gaps
- Failure of the door to close or latch
Replace damaged sections using the exact specified product, size and smoke-seal type.
Important Performance Note
The Pyroplex Rigid Box Pile Fire and Smoke Seal is one component within a complete fire-resisting doorset.
It does not independently create a 30-minute fire door, a 60-minute fire door, a smoke-control door or an acoustically rated door.
Final performance depends on:
- The tested door-leaf construction
- The frame
- The specified seal size and location
- The quantity of seals
- The associated ironmongery protection
- The threshold arrangement
- The surrounding construction
- The quality of installation and maintenance
Always follow the current doorset evidence, Pyroplex technical guidance and project fire-door specification.