>Trade Name: Astro Linear Joint Seal
Intumescent Expansion Joint Seal
> Quick Overview
- To reinstate fire resistance through rigid floors and walls.
- Linear construction joints.
- Tested to EN1366-4 : 2021 Fire resistance tests for service installations - Part 4: Linear joint seals.
- Available in five different widths to cover gap sizes from 10mm to 100mm in rigid walls and floors.
- Fire resistance period for rigid walls of up to EI120 dependent upon width.
- Fire resistance period for rigid floors of up to EI120 dependent upon width.
- Friction fit.
TO ORDER & SPECIFY
01329 844 500
sales@astroflame.com
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For in-stock items orders received before 2pm (Monday-Friday) are generally dispatched for delivery on the following working day (Monday-Friday).
> Product Description
The Astro Linear Joint Seal is an advanced intumescent thermoplastic designed to provide exceptional fire protection. It is formulated with flame retardants and binders that enable high-performance volume expansion and pressure sealing. Encased in an elastomeric, acoustically rated foam, the system allows for significant movement while maintaining its sealing properties.
This system is specifically designed to reinstate the fire resistance of wall and floor constructions in linear gap seals. It has been rigorously tested to EN 1366-4: 2021, the standard for fire resistance tests on service installations, specifically for linear joint seals.
The Astro Linear Joint Seals are available in five different widths, making it suitable for gap sizes ranging from 10mm to 100mm in rigid walls and floors. It offers a fire resistance period of up to EI120 for both rigid walls and floors, depending on the width of the seal.
Installation is simple and efficient, as the system is designed for a friction-fit application, ensuring a secure and reliable seal without the need for additional adhesives or fixings. This makes it an ideal solution for maintaining fire safety in buildings while allowing for structural movement and acoustic performance.
> Properties details
| Material | Intumescent thermoplastic filled with flame retardants and binders |
| Finish /Colour | Black |
| Chemical properties | See SDS latest version |
| Size/dimensions (product & installation spacial requirement) | 1000mm x 33.6mm x 50mm (LJS25) 1000mm x 55.4mm x 50mm (LJS35) 1000mm x 60.4mm x 50mm (LJS50) 1000mm x 92.2mm x 50mm (LJS75) 1000mm x 129mm x 100mm (LJS100) |
| Shelf life | 18 months if stored in accordance with storage conditions |
| Chemical Resistance / Limitations | Not to be used where joints are to be constantly immersed in water. Do not use on substrates that are likely to release solvents, oils or plasticizers. Not resistant to water, strong acids, strong bases, oxidizing agents (i.e. hydrogen peroxide), alcohols, hydrocar-bon solvents. |
> Testing / Classification
| Standard | Description | Result |
| EN1366-4 : 2021 | Fire resistance tests for service installations - Part 4: Linear joint seals | Please contact Technical : sales@astroflame.com |
> Fire Resistance Classifications
| Product Code | Product Description | Joint Width (mm) | Rigid Walls (Vertical Linear Joint) | Rigid Floors |
| AFLJS25 | Astro Linear Joint Seal 10-25mm | 10 - 25mm | E 240, EI 120 | EI 120 |
| AFLJS35 | Astro Linear Joint Seal 26-35mm | 26 - 35mm | E 240, EI 120 | EI 120 |
| AFLJS50 | Astro Linear Joint Seal 36-50mm | 36 - 50mm | E 240, EI 120 | EI 120 |
| AFLJS75 | Astro Linear Joint Seal 51-75mm | 51 - 75mm | EI 90 | E 90, EI 60 |
| AFLJS100 | Astro Linear Joint Seal 76-100mm | 76 - 100mm | EI 120 | E 120, EI 90 |
> Product Availability
Supplied in metre lengths. When ordering please state product code and number of metre lengths required.
| Product Code | Product Description | Size |
| AFLJS25 | Astro Linear Joint Seal 10-25mm | 1000mm x 33.6mm x 50mm |
| AFLJS35 | Astro Linear Joint Seal 26-35mm | 1000mm x 55.4mm x 50mm |
| AFLJS50 | Astro Linear Joint Seal 36-50mm | 1000mm x 60.4mm x 50mm |
| AFLJS75 | Astro Linear Joint Seal 51-75mm | 1000mm x 92.2mm x 50mm |
| AFLJS100 | Astro Linear Joint Seal 76-100mm | 1000mm x 129mm x 100mm |
> To Order & Specify
Please contact us and quote the following information - Please quote- Quantity / Product Code / Product Description / Size
Typical wording:- 10 / AFLJS25 / Astro Linear Joint Seal 10-25mm / 1000mm x 33.6mm x 50mm
>> Tel: 01329 844 500 or >> Email: sales@astroflame.com
> Installation
We have technical representatives who provide assistance in the selection and specification of the products on this site and should be consulted for exact installation and product suitability. Ensure an early engagement with ourselves, designers, main contractor and specialist installers before any installation. Other trades and/or manufacturers may need to be consulted. For in-depth information, specification and technical advice please call our Head Office on tel 01329 844 500 or email sales@astroflame.com
> Maintenance
All interested parties, designer, specifier, main contractor and specialist installers should provide access to allow the fire stopping seals to be regularly inspected and maintained, as well as records kept of such maintenance at minimum periods of 12 months, as required by the Regulatory Reform Order, and repaired if necessary. Reference should be made to ASFP TGD 17 – Code of Practice for the Installation and Inspection of Fire Stopping.
> Competency
It is vital that those entrusted to design or install a fire stopping product have the necessary levels of competence to undertake the task professionally and thoroughly. The level of competency required will be commensurate with the expected complexity of the building. All designers must eliminate, reduce or control foreseeable risks that may arise during installation, construction or maintenance when preparing or modifying designs. Clients should ensure that the principal designer and principal contractor carry out their duties under CDM regulations. The ASFP foundation course in passive fire protection provides essential knowledge as part of demonstrating competency and understanding in this key fire protection specialism.
> Additional Notes
For further information on installation requirements please refer to the wall/floor specification to ensure the compatibility of this product, if in doubt please contact the technical team with the wall/floor specification on: tel 01329 844 500 or email sales@astroflame.com
> Health and Safety
The product does not present any known health hazards during or after installation. Normal good industrial and personal hygiene practices should be observed. For further information on health and safety requirements please contact the technical team on: tel 01329 844 500 or email sales@astroflame.com
> Document Downloads
> Delivery/Returns
For in-stock items orders received before 2pm (Monday-Friday) are generally dispatched for delivery on the following working day (Monday-Friday). All dates quoted for despatch are estimates only and are not guaranteed. We will endeavour to meet these dates but shall have no liability for any delay in despatch or delivery or any damage or loss occasioned thereby. We may deliver products pursuant to any order by instalments. If we are unable to deliver the goods for any reason,you will be contacted and you will not be obliged to pay for the goods which have not been delivered, you also have the option to cancel the goods that have been delivered, however we shall not be liable for any loss of income or profit which may have been caused by the delay or non delivery of goods.
For information about our returns policy please click here.
> Ask a Question
If you've got a question about this product or need some technical help get in touch with the Astroflame sales or technical team to discuss your requirements today. We are open Monday to Friday 8:00am to 5:30pm. You can always contact us on the following:
Web Page Last Modified: 17th March 2026