ISL Therm-A-Flex Glazing Seal – 2100mm is a flexible, self-adhesive graphite intumescent strip suitable for approved fire-sealing and fire-glazing applications where a rigid strip would be impractical.
The material remains flexible during normal conditions, allowing it to follow glazing beads, aperture edges and other closely controlled construction details. When exposed to fire conditions, the graphite-based material expands with firm pressure to help close the available gap and restrict the passage of flames and hot gases.
The stocked range is available in:
Every profile is supplied in a fixed 2100mm length with a self-adhesive backing.
Therm-A-Flex is manufactured from an intercalated graphite-based intumescent material.
Its flexibility makes it particularly useful where a rigid intumescent strip would be difficult to position accurately. The material can accommodate corners, curved surfaces and tightly controlled construction details while remaining resistant during normal building use.
Potential supported uses include:
This product listing is intended for the supplied glazing-seal profiles. The exact application must still be supported by evidence for the complete construction.
When Therm-A-Flex is specified within a fire-glazing system, it may be positioned around the glazed aperture or associated glazing components to provide intumescent protection around the glass.
A complete fire-resistant glazing system may also require:
Therm-A-Flex is not a complete glazing system and does not structurally retain the glass.
The manufacturer describes Therm-A-Flex as a high-expansion graphite product that develops firm pressure when activated by heat.
This expansion can help:
The expansion pressure means the selected width, position and available expansion space must match the tested or assessed construction.
Do not add extra layers or substitute a wider profile on the assumption that more material will improve fire performance.
Each stocked Therm-A-Flex strip has a self-adhesive backing for surface mounting.
The adhesive helps retain the strip while the remaining glazing or construction components are assembled.
The adhesive does not replace:
The receiving surface must be clean, dry and free from dust, grease and loose finishes.
The supplied 10mm profile is described as Black in the supplier price list, while technical product literature describes Therm-A-Flex as Dark Grey.
Both descriptions refer to the natural dark graphite appearance of the intumescent material. Colour should therefore be treated as a fixed product characteristic rather than a selectable variation.
The three widths are not automatically interchangeable. Use the exact dimensions stated by the glazing-system, doorset or fire-assessment evidence.
Each product is supplied as one 2100mm strip.
The number of lengths required depends on:
Measure the complete required sealing perimeter before calculating the quantity.
The manufacturer’s Therm-A-Flex technical data references fire resistance in accordance with BS 476: Part 22 and Certifire CF387.
This does not provide every 2mm strip with a universal standalone fire rating. The permitted performance depends on the complete tested or assessed assembly and the product dimensions, cross-sectional area and installation position stated within that evidence.
Before ordering, confirm:
| Product Name | ISL Therm-A-Flex Glazing Seal – 2100mm |
| Manufacturer | Intumescent Seals, a division of Dixon International Group Ltd |
| Product Range | Therm-A-Flex |
| Product Type | Flexible self-adhesive graphite intumescent strip |
| Stocked Widths | 10mm, 15mm and 20mm |
| Thickness | 2mm |
| Length | 2100mm |
| Colour | Black / Dark Grey Graphite |
| Material | Intercalated or exfoliating graphite-based intumescent material |
| Fixing | Self-adhesive backing |
| Expansion Characteristic | High-expansion material developing firm pressure |
| Published Fire-Test Reference | Fire resistance in accordance with BS 476: Part 22 |
| Manufacturer Certification Reference | Certifire CF387; applicability must be checked against the complete assembly and selected dimensions |
| Standalone Fire Rating? | No — performance depends on the complete tested or assessed construction |
| Standalone Smoke Rating? | No separate cold-smoke classification should be assumed for these plain strips |
| Standalone Acoustic Rating? | No |
| Profile Size | Length | Finish | Product Code |
|---|---|---|---|
| 10 × 2mm | 2100mm | Black / Dark Grey Graphite | THFLEX/10X2/SA |
| 15 × 2mm | 2100mm | Black / Dark Grey Graphite | THFLEX/15X2/SA |
| 20 × 2mm | 2100mm | Black / Dark Grey Graphite | THFLEX/20X2/SA |
| Width Options | Thickness | Length | Total Variations |
|---|---|---|---|
| 10mm, 15mm and 20mm | 2mm | 2100mm | 3 |
The stocked Product Codes use the following format:
THFLEX / Width × Thickness / SA
Where used within a glazed fire door or screen, performance depends on:
Store Therm-A-Flex:
Do not install material that is:
Therm-A-Flex must be installed in the dimensions and position required by the applicable fire-test, doorset or glazing-system evidence.
The manufacturer does not provide one universal glazing arrangement for every Therm-A-Flex application. Confirm the complete specification before applying the strip.
Confirm:
Do not modify a certified fire door unless the proposed glazed aperture and sealing arrangement are supported by suitable evidence.
Check that the prepared opening is:
The surface receiving the self-adhesive strip must be:
Remove all cutting and machining debris before installation.
Establish the exact location specified by the approved construction.
Depending on the system, Therm-A-Flex may be applied to:
Do not assume that the same position applies to every doorset or glazing system.
Measure the first required section and transfer the measurement without stretching the Therm-A-Flex.
Cut the strip cleanly using a suitable sharp hand tool.
The cut should be:
Peel back a short section of the release liner.
Align the Therm-A-Flex with the specified position and press the adhesive surface firmly against the prepared substrate.
Remove the liner progressively while applying the remainder of the strip.
Do not:
Measure, cut and install the remaining sections.
At each joint:
Check the installed strip for:
Replace defective sections before installing the glass.
Install the specified setting blocks, fire-resistant glass and glazing beads in accordance with the complete approved detail.
Ensure that:
The self-adhesive backing must not be relied upon to retain the glass or replace mechanical bead fixings.
Confirm that:
Inspect the glazed aperture or protected construction as part of the relevant fire-safety maintenance programme.
Check for:
Therm-A-Flex does not independently provide a universal fire-resistance period.
Final performance depends on the complete tested or assessed construction, including the selected strip dimensions, its position, the glass, the glazing beads, the door or screen construction and the quality of installation.
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