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FSi Products

FSi is a trusted manufacturer of passive fire protection systems, supplying a wide array of high-performance products that help contain fire, smoke, and harmful gases within buildings. Their solutions include fire stopping sealants, fire stopping coatings, fire rated cavity barriers, and other essential materials – all rigorously tested to meet UK building regulations and third-party approvals. Whether you’re involved in new builds, renovations, or retrofit works, FSi products are engineered for safety, compliance, and ease of installation.

At Rawlins Paints, we offer a handpicked selection of FSi systems tailored to the needs of contractors, facilities managers, and specifiers. From sealing service penetrations to protecting cavities and voids, the FSi range supports comprehensive compartmentation, acoustic insulation, and smoke control. With solutions suitable for a variety of substrates and designed to accommodate structural movement, our FSi category makes it simple to find products that work effectively across diverse project requirements.

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FSi Pyrocoustic Fire Resistant Sealant

FSi Pyrocoustic Fire Resistant Sealant

Water-based acrylic sealant used to reinstate the fire resistance of wall and floor constructions in linear joints and where apertures are penetrated by multiple services. Developed utilizing specialist polymer technologies allowing it to be tested and Certified to internationally recognised standards, including Certifire, CE marking and UL...

Price £52.85 (incl. VAT)
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FSi Stopseal 50/60 Fire Batt | Ablative-Coated Stonewool Boards

FSi Stopseal 50/60 Fire Batt

An ablative-coated stonewool board used to reinstate the fire resistance performance of internal wall and floor constructions where apertures are penetrated by single or multiple services. Prevention of air leakage and provides smoke seal Maintains Acoustic performance Assumed working life 30 years Highly flexible, high performance...

Price £21.23 (incl. VAT)
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FSi PenoPatch 60 Minute Fire Resistance For Cable Penetration In Walls

FSi PenoPatch

Putty based penetration sealing device for small cables and conduits in flexible and rigid walls. Easy installation Up to EI60 fire resistance 2 different size combinations, covering most small openings Note: 60mm size is now discontinued Ideal for Historical Building Upgrades or new build Fire resistance testing to EN 1366-3 60...

Price £58.37 (incl. VAT)
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FSi Pyrolastic Fire Resistant Silicone Sealant | 240Mins Anti-Fire Protection

FSi Pyrolastic Fire Resistant Silicone Sealant

One-part, neutral curing silicone for construction joints. Pyrolastic cures at room temperature under the action of atmospheric moisture to give a permanently flexible silicone rubber. Prevention of air leakage - Maintains acoustic performance, Assumed working life of 25 years Highly flexible - Cold smoke seal - Wide range of backing...

Price £168.22 (incl. VAT)
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FSi PipeBloc PCP Intumescent Pipe Collars | Passive Fire Stopping

FSi PipeBloc PCP Intumescent Pipe Collars

Designed and tested to seal service penetration apertures containing plastic and metallic pipes with insulation or cables. They are developed to provide a high volume expansion and pressure seal during a fire. The ultra thin design of the collars means the collar shell can give a depth of 30mm and 40mm ensuring that they can be installed into...

Price £11.74 (incl. VAT)
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FSi Putty Pads For Electrical Sockets In Rigid & Flexible Walls

FSi Non-Setting Putty Pads

Pre-cut system designed for easy application with single and double electrical sockets back boxes where fire resistance must be upheld in the event of a fire, installed within both flexible and rigid wall systems. The putty is also available in 1KG pails. To reinstate fire resistance through walls Where single and/or double plastic socket...

Price £89.81 (incl. VAT)
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FSi Silverseal HS Fire Stopping Mortar Compound

FSi Silverseal HS Compound

Gypsum based mortar material used to reinstate the fire resistance performance of floor and wall constructions where apertures exist for the penetrations of multiple services. Silverseal HS Compound, once cured has excellent load bearing capabilities and can be installed in large span openings. Large unsupported spans No shrinkage Easy to...

Price £25.82 (incl. VAT)
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FSi Stopseal Ablative Coating For Firestopping Batts & Slabs

FSi Stopseal Ablative Coating

Highly advanced flexible coating for use when installing the Stopseal Batt System. The Stopseal Ablative Coated is used to seal in the Stopseal Batt to reinstate the fire resistance performance of wall and floor constructions where apertures are penetrated by single or multiple services. Simple to install, through spray or brush application...

Price £26.64 (incl. VAT)
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FSi PyroPro HPE Intumescent Graphite Sealant | Fire Stopping

FSi PyroPro HPE Intumescent Graphite Sealant

Water based acrylic sealant used to reinstate the fire resistance of wall and floor constructions in apertures when penetrated by multiple services. Developed utilizing specialist intumescent technologies which result in the sealant expanding in the presence of heat or fire. Tested with a wide range of services, including plastic pipes,...

Price £161.78 (incl. VAT)
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FSi S-Line Fire Pillows | Temporary & Permanent Fire Barriers

FSi S-Line Fire Pillows

Creates a temporary or permanent fire barrier around all types of services to prevent the passage of fire through a compartment wall or floor, especially suitable where services are continuously being changed or replaced. Assumed working life 25 years For internal use Fire Resistance EN 1366-3 EI 120 and BS 476 - 240mins Fire...

Price £119.39 (incl. VAT)
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FSi PipeBloc PWP Intumescent Pipe Wrap

FSi PipeBloc PWP Intumescent Pipe Wrap

Designed and tested to seal service penetrations in apertures containing combustible plastic pipes. Developed utilizing specialist intumescent technologies which result in the wrap expanding in the presence of heat or fire, this expansion is fast acting and up to 25 times. To reinstate fire resistance through walls and floors To seal...

Price £36.59 (incl. VAT)
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FSi Paraflam SEB Cavity Barrier | Curtain Walling Fire Protection

FSi Paraflam SEB Cavity Barrier

A perimeter barrier designed for curtain walling, a non-combustible stone wool based product with a foil facing which prevents fibre migration and provides an excellent seal. Dry fit (no cure time required) Easy friction fit system High speed installation Lightweight Testing in voids up to 590mm Provides smoke seal Minimal waste...

Price £44.44 (incl. VAT)
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FSi PS Coating

FSi PS Coating

Ablative, highly advanced flexible coating used to apply to uncoated stonewool boards to reinstate the fire resistance performance of wall and floor constructions where apertures are penetrated by single or multiple services. Can be installed onto uncoated stone wool of a minimum thickness of 50mm and a minimum density of 140kg/m³...

Price £31.85 (incl. VAT)
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FSi Pass-it Transit System | Fire Stopping For Services

FSi Pass-it Transit System

Pre-assembled, multi layered intumescent device encased in a 2 part steel shell. It is designed to prevent the passage of fire between compartment floors and walls, offering smoke and acoustic isolation whilst still allowing for the easy installation/ removal of services. There are different sizes available depending on the number and size of...

Price £59.76 (incl. VAT)
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FSi Silverseal STD Fire Stopping Mortar Compound

FSi Silverseal STD Compound

Gypsum based mortar material used to reinstate the fire resistance performance of floor constructions where apertures exist for the penetrations of multiple services. No shrinkage. Excellent yield. Easy to mix. Versatile workability range. Provides smoke seal. Manufactured and tested alongside the entire FSi Fire Stopping range in the...

Price £25.51 (incl. VAT)
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FSi Flexi Coat Flexible Ablative Coating | Fire Sealing System

FSi Flexi Coat Flexible Ablative Coating

Highly advanced flexible penetration and aperture sealing system, supplied in the form of both completed pre-coated Flexi-Coat Fingers and as a coating to be applied to stone/mineral wool backing material. Tested in accordance with EN1364-4 and is third party certified. To reinstate fire resistance through walls and floors Movement seals...

Price £125.80 (incl. VAT)
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FSi PyroPro LST Fire Resistant Sealant | London Underground-Approved

FSi PyroPro LST Fire Resistant Sealant

FSi PyroPro LST Fire Resistant Sealant is a water based acrylic sealant which has been developed utilizing specialist materials which significantly reduce smoke and toxic fumes in the event of a fire, therefore is authorised for use on the London Underground network, and other underground/ tunnel networks. Flexible, for use in gaps up to...

Price £120.20 (incl. VAT)
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FSi Green Wipes | Tool & Equipment Cleaning

FSi Green Wipes

Due to supply issues from the manufacturer, this product is temporarily unavailable. Specially formulated to provide a heavy-duty cleaning solution, removing: sealants, paints and coatings, adhesives, oil, foams, grease and other stains from hands, tools and general surfaces. Fully compliant with EU cosmetic legislation, with strong...

Price £64.42 (incl. VAT)
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FSi Ancillaries

FSi Ancillaries

A range of accessiores for use with FSi fire protection products. FSi Angle Fixings - For use with FSi fire protection products FSi Backing Rods - Used to ensure sealants are installed to their required depths FSi Fixings - Fixings for use with FSi fire protection products during application FSi Sealant Applicator Guns - For use with...

Price £13.48 (incl. VAT)
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Silverliner Open State Cavity Barrier

Silverliner Open State Cavity Barrier

Developed to protect the voids between the outer façade and the inner construction element of the building. Designed for use in a ventilated façade, the Silverliner OSCB allows for 25mm or 50mm linear air gap to ensure movement of air and drain any moisture within the facade. The aluminium foil restricts fibre migration and offers a class ‘0’...

Price £0.00 (incl. VAT)
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FSi Thermal Defense Wrap

FSi Thermal Defense Wrap

Thermal Defense Wrap has been developed to prevent the passage of fire and smoke between fire resisting compartments where there is a service penetration. Designed to allow the movement services in use, maintain necessary insulation on services and prevent temperature rise of service on the cold face At normal temperatures, remains...

Price £16.68 (incl. VAT)
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FSi RW4 Stonewool Acoustic Board

FSi RW4 Stonewool Acoustic Board

Versatile building slabs for a wide range of general building applications, for thermal, acoustic and fire resistant insulation in general building applications. Excellent thermal, acoustic and fire insulation Non-combustible – Euroclass A1 More Information Delivery Info

Price £1010.26 (incl. VAT)
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Fire-Resistant Linear Joint Sealing System

FSi Stopseal LJS Linear Joint Seal

Intumescent thermoplastic sealing system for fire resistance. Suitable for use on rigid walls, rigid floors, and linear construction joints. Certified to ISO 9001 and Emicode EC 1+ standards for quality and low emissions. Offers up to 240 minutes of fire resistance (E 240, EI 120) in rigid walls and floors. Restricted to professional...

Price £301.80 (incl. VAT)
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FSi Passive Fire Protection Systems: Innovation, Performance, Compliance


FSi specialises in passive fire protection systems that help prevent fire and smoke from travelling through voids, service penetrations, and cavities within a building’s construction. From construction joints and gaps between floors to cable trays, ducting, and pipework, these critical weak points are common vectors for fire to spread – and FSi products are expertly engineered to seal, insulate, and contain these vulnerabilities.

Their extensive product suite fire stopping intumescent sealants that expand when exposed to heat, creating a robust char barrier, alongside fire collars, wraps, and pillows that maintain the fire resistance of walls and floors. FSi’s barrier systems are particularly well-regarded in the industry, with options for vertical and horizontal applications and compatibility with both rigid and flexible wall constructions. Acoustic insulation and air permeability performance often come built-in, delivering added functionality beyond fire protection alone.

Each solution undergoes rigorous third-party testing and certification, offering peace of mind and verifiable compliance. Importantly, FSi continues to innovate in alignment with evolving legislation and practical on-site requirements. Their products not only make specifying easier but reduce the risk of installation error thanks to clear labelling, simple handling, and compatibility with other materials. As part of a larger passive fire strategy, these products form an essential barrier network designed to protect life and property by preventing fire escalation and allowing more time for safe evacuation.

Frequently Asked Questions


What are the main uses of FSi firestop sealants and intumescent products?

FSi sealants and intumescent products are primarily used to maintain fire resistance where services such as cables, pipes, or ducts pass through walls or floors. They help restore the compartmentation integrity of the building, which is critical for containing fire and smoke within a designated area. Common applications include sealing cable trays, conduits, HVAC ductwork, pipework penetrations, and linear joints in walls and floors. Some products are also effective for maintaining acoustic separation and preventing drafts.

How do fire collars and wraps work in passive fire protection?

Fire collars and wraps are designed to protect plastic pipes that pass through fire-rated walls and floors. When exposed to high temperatures, the intumescent material within the collar or wrap expands rapidly, crushing and sealing the softening plastic pipe to prevent the passage of fire and smoke. Fire collars are typically installed around pipes and fixed to the surface, while wraps are flexible solutions that can be fitted into smaller or awkward spaces prior to being sealed in place with mortar or compound.

Do FSi products need to be used with specific substrates?

Many FSi products are designed for use across multiple common building substrates, including concrete, masonry, gypsum, and plasterboard. Some items, such as certain fire sealants, are formulated to maintain strong adhesion and fire performance on porous and non-porous surfaces alike. Always refer to the individual product datasheet and certification documents to confirm suitability with your specific materials and to ensure full compliance with test standards and fire resistance classifications.

What certification standards do FSi fire protection products typically meet?

FSi products are often tested to EN standards such as EN 1366 for fire resistance and EN 13501 for classification of reaction to fire. In addition, they may carry third-party approvals through internationally recognised schemes such as Certifire or ETA (European Technical Assessment). These standards provide assurance that the products have been independently tested under rigorous conditions to demonstrate their performance in real-life scenarios. Be sure to check each product's certification for its intended application and limits of use.

Can FSi products be used in combination for complete compartmentation systems?

Yes, FSi systems are often designed to work in conjunction with one another as part of a broader firestopping and compartmentation approach. For example, a project might require a fire barrier for a cavity wall, sealants for linear gaps, collars for pipe penetrations, and ablative-coated batt for larger service clusters. These systems can be specified together to create a continuous fire-resistant envelope, provided all elements are used within their tested configuration and installation guidelines.