A firestop sealant for construction joints that promises up to four hours of fire resistance, Bostik Fireseal Silicone FP402. Contractors and installers gain confidence from a formulation that resists smoke ingress while standing up to weather and UV exposure. Is the formulation and application performance suitable for demanding, safety-critical projects?
⚡ At a Glance
- • Fire Performance: Tested for up to four hours in linear joints under EN 1366-4
- • Best for: Sealing linear joints up to 50mm where certified fire stopping is required
- • Not ideal for: Applications with joint widths exceeding 50mm
Certified to EN 1366-4 and assigned fire class B-s1,d0 under EN 13501-1. Weather and UV resistance combine with a MEKO-free silicone formulation for robust external performance.
Reliable fire containment – thanks to EN 1366-4 tested formulation
Performance has been evaluated under EN 1366-4 for linear joints and is covered by ETA 20/1249, with fire class B-s1,d0 according to EN 13501-1 and smoke leakage Sa / S200 per EN 1634-3. The testing demonstrates behaviour under standardised fire exposure for joint systems.
Confidence in meeting regulatory test expectations when sealing compartmentation joints, helping maintain fire separation and reduce smoke spread risk.
Neat, dependable application – with non-slump silicone for up to 50mm joints
Formulation allows application into joints up to 50mm wide and is described as having excellent application with no slump, suitable for vertical and horizontal sealing tasks. Cartridge-friendly rheology supports controlled tooling and finish.
Faster, cleaner installation on site with reduced need for corrective work, giving consistently neat joints in typical construction scenarios.
Weatherproof performance – with UV, water and weather resistance and MEKO-free formulation
The sealant resists UV exposure, moisture and general weathering, and its MEKO-free composition avoids the use of that specific solvent class. Durability factors have been considered for external exposures.
Suitable for exposed joints without rapid degradation and safer handling related to MEKO absence during installation.
✨ The 4 Key Reasons for Bostik Fireseal Silicone FP402
- EN 1366-4 tested – Provides verified performance for linear joint fire-stopping compliance
- B-s1,d0 classification – Limits flame spread and keeps smoke production low during fire
- Non-slump silicone – Smooth application in vertical joints up to 50mm wide
- UV, water and weather resistant – Remains stable outdoors without premature degradation or breakdown
📋 Technical Details at a Glance
- Category: Firestop silicone sealant
- Fire Resistance: Up to 4 hours in linear joints
- Standards / Approvals: EN 1366-4, EN 13501-1 (B-s1,d0), EN 1634-3 (Sa / S200), ETA 20/1249
- Joint Width: Suitable for joints up to 50mm
- Application Properties: Non-slump, excellent application
❓ Frequently Asked Questions
Q: How long does the sealant resist fire?
A: Rated for up to four hours in linear joints, based on testing to EN 1366-4 and supported by ETA 20/1249.
Q: Can the sealant be used outdoors?
A: Yes, UV, water and weather resistance are specified, making it suitable for exposed locations.
Q: What maximum joint width can be filled?
A: Suitable for application in joints up to 50mm wide, with a non-slump formulation for neat finishes.
🏆 Our Verdict
Suitable for contractors and installers who need certified fire-stopping for linear joints, particularly where exposure to weather is a factor. The combination of EN 1366-4 testing, B-s1,d0 classification and a non-slump, MEKO-free silicone formulation is the key selling point. Without price details here, the tested performance and durability suggest strong long-term value for safety-critical installations.
