Passive Fire Joints

Key Takeaways: 

  • Passive fire sealing helps contain the spread of fire, smoke, and toxic gases through joints, gaps, and penetrations.
  • Effective compartmentation gives occupants more time to evacuate and supports safer emergency response.
  • Soudal Firecryl Acrylic Sealant is an intumescent sealant, meaning it swells and expands when exposed to high heat, forming an insulating char layer that helps slow the spread of fire, which provides flexible, paintable fire and smoke protection for general sealing applications.
  • Soudaseal FR delivers up to 4 hours of fire resistance, with superior UV, heat, and moisture durability for internal and external joints. 

What is Passive Fire Sealing? 

Passive fire sealing is an essential part of modern fire protection systems. It prevents fire, smoke, and toxic gases from spreading through joints, gaps, and service penetrations in walls, floors, and ceilings, maintaining the integrity of a building’s fire-rated compartments. This barrier effect helps slow down the spread of flames, giving people more time to evacuate safely and allowing emergency responders to act before the fire spreads. 

To achieve proper fire compartmentation, Soudal offers a range of high-performance sealant solutions. 

Soudal Firecryl Acrylic Sealant is a fire-resistant, smoke-tight, plasto-elastic sealant based on acrylic dispersion. It expands (intumesces) when exposed to temperatures above 120°C, swelling to form an insulating char layer that seals gaps and helps slow the spread of fire and smoke. It’s waterproof after curing, paintable, and offers excellent adhesion on porous surfaces, making it ideal for use around walls, ceilings, and service penetrations in both residential and commercial settings. 

For higher performance or exposed applications, Soudaseal FR is a fire-rated SMX hybrid polymer sealant that provides up to 4 hours of fire resistance, tested to AS 1530.4 standards. It’s built to withstand UV exposure, high humidity, and coastal conditions, making it suitable for both internal and external use. With strong adhesion to concrete, AAC, brick, block, and plasterboard, it delivers long-term flexibility and reliability. Low in VOCs and paintable with water-based paints, Soudaseal FR ensures a durable, neutral-cure finish without damaging surrounding materials. 

Shop the full range of fire-rated solutions, or if you need further assistance or technical support, contact our team on 0800 70 10 80. 

FAQs

What is the difference between Firecryl and Soudaseal FR?

Firecryl is an acrylic-based, intumescent, paintable fire and smoke sealant suitable for standard joints, while Soudaseal FR is an SMX hybrid polymer sealant providing up to 4 hours of fire resistance for more demanding or exposed applications.

Can these sealants be painted?

Yes, both Firecryl Acrylic Sealant and Soudaseal FR can be painted with water-based paints after curing.

Are they suitable for external use?

Soudaseal FR is designed for both internal and external applications and withstands UV, moisture, and coastal conditions. Firecryl is best for internal use or sheltered locations.

Do these products prevent smoke as well as fire?

Yes, both products are smoke-tight and intumesce under heat, effectively blocking fire, smoke, and toxic gases from spreading through joints.