When it comes to protecting buildings from the devastating effects of fire, passive fire protection plays a crucial role. An effective, flexible solution for sealing cable penetrations is the intumescent fire pillow. Often overlooked but highly effective, these cushion-like products help maintain fire compartmentation within buildings.
In this blog, we’ll explore what intumescent fire pillows are, how they work and where they can be installed.
What is an Intumescent Fire Pillow?
An intumescent fire pillow is designed to seal openings in fire-rated walls or floors, particularly where services such as metal cable trunking pass through. Shaped like a pillow, they contain a blend of intumescent material and organic fillers enclosed in a fire-resistant fabric casing.
Their primary purpose is to prevent the spread of fire by expanding and sealing gaps when exposed to high temperatures. Fire pillows are especially useful in electrical and mechanical service penetrations where cabling often leaves unsealed voids that could allow fire to spread.
How do Intumescent Fire Pillows work?
The term “intumescent” refers to the material’s ability to swell significantly when heated, typically at temperatures around 100–180°C. When exposed to fire, the heat triggers a chemical reaction, causing the material to expand many times its original size.
In a typical service penetration, such as cable trunking, the space around the cables isn’t always fully occupied. These gaps create a direct path for fire and smoke to move between compartments, unless adequately sealed.
As the intumescent material expands, it forms an insulating barrier that fills the gaps and prevents fire and smoke from passing through. This reaction helps to:
- Block fire, smoke and toxic gases
- Reinforce fire compartmentation for a specific period of time (commonly two or four hours)
- Maintain the integrity of fire-rated walls or floors
Because of their lightweight, removable structure, fire pillows are ideal for areas where services are likely to be updated or changed over time. Unlike rigid fire-stopping methods, pillows can be removed easily and reinstalled without damaging the surrounding structure.
Want to learn more about how intumescent materials react to heat? Visit our blog.
Where can Fire Pillows be installed?
Fire pillows can be installed in rigid walls and also within rigid floor constructions. During a fire, the pillow will expand to several times their original volume to form an effective seal.
Intumescent fire pillows are commonly used in:
- Electrical trunking and cable trays
- Service penetrations in walls and floors
- Data centres and communication rooms
- Riser cupboards
- Temporary fire-stopping solutions during construction
They are particularly valuable in locations where ongoing access to services is required, or where frequent changes to wiring or cabling occur.
Benefits of using Fire Pillows
- Easy to install - No specialist tools or sealants are required.
- Flexible and removable - They are removable and reusable, making them ideal for areas where access is needed for ongoing maintenance or changes to service layouts.
- Effective fire protection - Can provide up to 4 hours of fire resistance (depending on the manufacturer and application).
- Low maintenance - Once in place, they require little attention.
Compliance and fire-ratings
To ensure safety and compliance, intumescent fire pillows must be tested to relevant standards such as BS EN 1366-3 for penetration seals.
Always check that the fire pillow you’re using is CE marked and approved for your specific application.
Fire pillows are often used as part of a comprehensive fire-stopping system and should be installed in accordance with the manufacturer's guidance.
At FireSealsDirect, we offer a range of high-performance fire pillows in various sizes from trusted brands including Rockwool, FSi and Quelfire.
How we can help
We are a family-run business with 50 years of experience in fire safety, supplying a wide range of passive fire protection products to help keep buildings across the UK safe and compliant.
Our friendly and knowledgeable customer care team are here to assist you with product advice, installation queries, or any questions about your property’s fire protection needs. Get in touch using our live chat feature, email us at [email protected] or call us on 02920 857 959.
For more helpful information on fire legislation, installation guidance and more, visit our Advice Centre.
