1. Fire Resistance Mechanism
The core fire resistance of gypsum boards stems from their material composition and structural design. When exposed to high temperatures, gypsum (CaSO₄·2H₂O) undergoes a dehydration reaction, releasing water molecules and absorbing significant heat, thereby delaying temperature rise on the unexposed side. Additionally, reinforcing materials such as glass fibers or vermiculite embedded in the board maintain structural integrity after dehydration, preventing collapse.
2. Typical Fire-resistant Construction Designs
(1) Single-layer Construction
Uses 12-15mm thick fire-resistant gypsum boards directly mounted on light-gauge steel studs.
Suitable for low fire-risk areas (e.g., residential partition walls).
Fire resistance rating: Typically 30-60 minutes.
(2) Double-layer Composite Construction
Features staggered installation of two layers of fire-resistant gypsum boards with rock wool or other Class A fireproof insulation in between.
Enhances fire resistance to 90-120 minutes.
Commonly used in fire-rated partitions for commercial buildings.
(3) Steel Column/Beam Encasement
Combines fire-resistant gypsum boards with calcium silicate boards to form a multi-layer encasement system.
Testing shows that a 25mm thick multi-layer encasement can extend the fire resistance of steel structures to over 180 minutes, meeting the requirements of GB50016 (China's Code for Fire Protection Design of Buildings) for load-bearing structures.
3. Key Construction Techniques
Joint Treatment: A 3-5mm expansion gap between boards must be filled with fire-rated joint compound to prevent cracking under thermal stress.
Stud Fireproofing: Light-gauge steel studs should be coated with fire-resistant paint to prevent premature softening in a fire.
Penetration Sealing: Firestop putty or intumescent sealants must be used where cables or pipes pass through to prevent flame spread.
4. Performance Testing & Standards
Fire-resistant gypsum board assemblies must comply with GB/T 9978 fire resistance tests, ensuring:
Integrity: No sustained flames on the unexposed side.
Insulation: Average temperature rise ≤140°C (single point ≤180°C).
Load-bearing Capacity: No structural collapse (for load-bearing assemblies).
5. Future Trends
As fire safety regulations tighten, fire-resistant gypsum boards are evolving in the following directions:
High-performance Composites: Integration with aerogel insulation for ultra-thin systems with ≥240-minute fire ratings.
Smart Monitoring: Embedded thermal sensors for real-time fire risk detection.
Eco-friendly Improvements: Use of industrial byproducts (e.g., phosphogypsum) to reduce carbon emissions.
Conclusion: Optimized construction design and strict installation practices are critical for maximizing fire resistance. With material innovations and system enhancements, fire-resistant gypsum boards will see expanded use in high-risk buildings.
