1. Fire Standards & A1 Classification
What makes a material truly non-combustible? Understanding the classification system is essential for specifiers, architects, and fire engineers selecting a calcium silicate fire board.
EN 13501-1 Classification
The European standard classifies construction products by reaction to fire: A1 (no contribution to fire at any stage, including fully developed), A2 (negligible contribution), B through F (increasing contribution). GF-1100 achieves Class A1 inherently — no fire retardant additives, no halogenated compounds, no intumescent coatings. The material itself cannot burn. Testing confirms zero heat of combustion (PCS ≤2.0 MJ/kg per EN ISO 1716), zero flame spread, zero smoke production, and zero flaming droplets/particles.
GB 8624 Classification
Under Chinese national standard GB 8624, GF-1100 achieves Grade A1 (the highest classification), confirming it as a non-combustible material. This classification is mandatory for fire door core materials and structural fire protection in Chinese building codes. The board also meets GB 12955 requirements for Class A fire doors (120-minute rating with a 40mm core), tested and certified at accredited Chinese fire test laboratories including the Sichuan Fire Science Research Institute.
Endothermic Dehydration Mechanism
GF-1100's fire performance is not chemical trickery — it is physics. The board's xonotlite crystal structure (6CaO·6SiO&sub2;·H&sub2;O) contains chemically bound water within the crystal lattice. When heated above approximately 400–450°C, this water is released endothermically — absorbing approximately 2,260 kJ per kg of water released. This heat absorption delays temperature rise on the unexposed face, contributing directly to the board's fire resistance rating. After dehydration, the remaining calcium silicate skeleton remains dimensionally stable and structurally intact to 1100°C. Unlike gypsum (which loses all structural integrity when CaSO&sub4;·2H&sub2;O dehydrates at ~150°C), GF-1100 continues to provide a physical thermal barrier after its chemically bound water is released.
2. GF-1100 Product Specifications
The GF-1100 is a medium-density calcium silicate fire board (350–450 kg/m³) formulated specifically for passive fire protection. It balances thermal insulation, mechanical strength, and workability for fire door manufacturing, structural steel encasement, and fire compartmentation.
| Property | GF-1100 Value | Standard |
|---|---|---|
| Density (dry) | 350–450 kg/m³ | GB/T 10699 |
| Compressive Strength | ≥2 MPa | GB/T 5072 |
| Flexural Strength | ≥1.5 MPa | GB/T 10699 |
| Thermal Conductivity @ 200°C | ~0.09 W/m·K | GB/T 10294 |
| Thermal Conductivity @ 600°C | ~0.14 W/m·K | GB/T 10294 |
| Maximum Service Temperature | 1100°C | — |
| Moisture Content (as supplied) | <10% | GB/T 10699 |
| Fire Classification | A1 (EN 13501-1) / A1 (GB 8624) | EN 13501-1 / GB 8624 |
| Asbestos Content | 0% (asbestos-free) | ISO 22262-1 |
| Linear Shrinkage @ 1100°C | <2% | GB/T 10699 |
| Surface Finish | Sanded both faces, smooth | — |
| Color | Off-white to light grey | — |
Standard sizes: 1200×600mm and 1000×500mm. Thicknesses: 20, 25, 30, 35, 40, 45, 50, 60mm. Both faces are sanded smooth for direct application of decorative finishes, laminates, or steel face sheet bonding. CNC routing available for door core blanks cut to exact frame dimensions, column casing pieces for specific steel sections, and complex shapes for penetration seals.
3. Fireproof Door Core Application
The largest-volume application for GF-1100 fireproof board is as the core material in steel fire doors. A 40mm GF-1100 core achieves a 120-minute fire integrity and insulation rating when tested to GB 12955 (China) or EN 1634-1 (Europe).
Lighter Than Vermiculite
GF-1100 (350–450 kg/m³) is approximately 20–30% lighter than vermiculite board cores (500–700 kg/m³) at equivalent fire rating. This reduces total door weight, which means lower hinge wear, easier manual operation (important for accessibility/Building Regulations Part M compliance), and the ability to use standard-duty hinges and closers rather than heavy-duty hardware. A typical 2100×900mm fire door with GF-1100 core weighs 55–65 kg versus 70–85 kg with vermiculite core.
Better Screw Retention
A 5mm diameter wood screw in GF-1100 board has a pull-out strength of approximately 200–300 N, versus 50–100 N in gypsum board core. This matters for hardware mounting: hinges, closers, locks, and panic bars must remain securely fixed throughout the door's service life. Loose hardware can compromise fire performance by creating gaps or allowing the door leaf to warp. GF-1100 maintains screw retention even after fire exposure — gypsum crumbles once dehydrated.
Zero Smoke Production
GF-1100 produces zero smoke when heated to any temperature. The only emission is water vapor (steam) from the endothermic dehydration reaction. There are no organic binders, no resins, no halogenated compounds — the board is 100% inorganic after the cellulose processing fibers burn out during manufacture. For fire doors in escape routes, stairwells, and corridors, zero smoke contribution is a critical life-safety requirement. Smoke inhalation, not burns, is the primary cause of fire fatalities.
Precise Thickness Tolerance
GF-1100 board is sanded to ±1mm thickness tolerance. This consistency is essential for reliable fire door fabrication: the steel face sheets must bond to the core across the entire surface, and any thickness variation creates bonding voids that compromise fire performance. CNC-cut door core blanks are supplied to the exact dimensions required for the door manufacturer's frame size, eliminating trimming waste at the door factory.
Tested door configurations: 40mm GF-1100 core in a standard 1.5mm steel-faced door achieves EI 120 (120-minute integrity + insulation) per GB 12955 Class A. 50mm core achieves EI 180 in some configurations. For 60-minute rated doors (EI 60), 30mm core is sufficient. Door sizes: standard blanks supplied for common door sizes; custom blanks for oversized and non-standard doors. Certification: GB 12955 fire test reports available upon request.
4. Structural Steel Fire Protection
Structural steel loses approximately 50% of its yield strength at 550°C. Building codes mandate that structural steel in multi-story buildings maintain load-bearing capacity for 60, 90, or 120 minutes in a fire. GF-1100 fireproof board encasement provides this protection with a dry, mechanical fixing system.
Board Encasement Method
GF-1100 boards are fixed around the steel column or beam to form a box enclosure. The air gap between the board and steel (typically 25–50mm) provides additional insulation. Boards are fixed with steel angles or channels at corners, secured with screws at maximum 250mm centers. Joints sealed with high-temperature inorganic adhesive (sodium silicate based).
Tested Thickness Ratings
For typical H-section columns with section factor ≤150 m&sup-1;, tested to ASTM E119 / EN 13381-4: 30mm GF-1100 board → 60-minute fire rating. 50mm GF-1100 board → 120-minute fire rating. Heavier sections with lower section factors may achieve longer ratings at the same thickness. Project-specific assessment available from our technical team — provide section size and required fire rating.
Advantages Over Alternatives
vs. Intumescent paint: No re-coating schedule, weather-independent installation, visible protection thickness. vs. Sprayed cementitious: No mixing/pumping/spraying equipment, no overspray waste, no curing time, consistent factory-controlled thickness. vs. Vermiculite board: Lighter (~20–30%), better screw retention, lower thermal conductivity at equivalent density. GF-1100 also provides physical impact protection to the steel from minor construction traffic.
5. Fire Compartmentation Systems
Beyond doors and structural steel, GF-1100 calcium silicate fire board is used in a range of passive fire protection systems that divide buildings into fire compartments.
Cable Tray Fire Barriers
In industrial buildings, data centers, and power stations, cable trays carry electrical cables through fire compartment walls and floors. GF-1100 board is cut to size on site and assembled into box enclosures around cable trays and busbar trunking. Joints sealed with inorganic adhesive. A 40mm board enclosure provides 120-minute fire integrity (tested to EN 1366-5) for the cables inside, preventing fire spread along the cable route through compartment boundaries.
Ventilation Duct Protection
Ventilation ducts in fire-rated shafts and smoke extraction ducts in car parks and atria require fire-rated encasement (EN 1366-8). 50mm GF-1100 board encasement around a galvanized steel duct achieves 120-minute fire rating (integrity + insulation). The smooth board surface minimizes additional duct pressure drop — important for fan sizing and system balance. Boards are fixed with steel angles, screws at 250mm centers, and joints sealed.
Penetration Seals & Partition Walls
Penetration seals: Where pipes, ducts, or cables pass through fire-rated walls/floors, GF-1100 board is cut to fit tightly around the penetrating service, with remaining gaps filled with intumescent sealant or firestop mortar. Partition walls: Two layers of 25mm board each side of 75mm steel studs with mineral wool in the cavity achieve EI 120. Unlike gypsum, GF-1100 is not degraded by water exposure — important in basements, plant rooms, and areas where pipe bursts are possible.
Project References
St. Maurice fireproof system — European fire door manufacturer using GF-1100 cores. Jinan Weidong residential complex — 2,400 apartment entrance doors across 12 towers, 50mm GF-1100 core, GB 12955 Class A. Zibo bus depot — cable tray fire barriers in an electric bus charging depot, 40mm GF-1100 enclosures, 120-minute rating. Multiple data center projects — cable penetration seals and fire-rated duct enclosures.
6. Installation Guide
GF-1100 calcium silicate fire board installs with standard tools and techniques. Following these guidelines ensures the designed fire rating is achieved in the completed installation.
Cutting
Cut with carbide-tipped circular saw (40-tooth blade), jigsaw with carbide blade, or score-and-snap for boards ≤25mm. Always use dust extraction and wear P2/N95 respiratory protection. Wet cutting suppresses dust. Cut edges that will be exposed should be sealed with a light brush coat of sodium silicate solution or specified edge sealant to prevent moisture absorption.
Fixing with Screws/Studs
For vertical installations (walls, column faces): stainless steel (304 or 316 grade) screws with 40mm diameter washers at 250mm centers, minimum edge distance 25mm. For overhead installations (ceilings, soffits): same spacing, ensure screws are driven into steel framing or studs with adequate pull-out capacity. Screw length: board thickness + 25mm minimum embedment into the substrate. Predrill screw holes slightly oversize to prevent local spalling.
Joint Sealing & Edge Treatment
Joint sealing: All board-to-board joints must be sealed with high-temperature inorganic adhesive (sodium silicate based) to prevent flame and hot gas penetration through gaps. For applications above 400°C service temperature, specify a phosphate-bonded sealant. Edge treatment: Exposed cut edges should be sealed as described above. Board edges at floor level should be protected from standing water. Multi-layer installations: Stagger joints between layers by at least 150mm to prevent aligned joint paths.
7. Certification Documents Available
For project specification and regulatory compliance, Mingfa provides comprehensive fire test documentation for the GF-1100 fireproof board.
EN 13501-1 Classification Report
A1 classification confirmed by accredited European fire test laboratory. Includes test data for heat of combustion (EN ISO 1716), non-combustibility furnace test (EN ISO 1182), and single burning item test (EN 13823).
GB 12955 / EN 1634-1 Door Test Reports
Full-scale fire door test reports for 40mm and 50mm GF-1100 core configurations. 120-minute and 180-minute ratings documented. Door construction details, hardware specifications, and installation requirements included.
Structural Steel Protection (EN 13381-4 / ASTM E119)
Fire resistance test reports for GF-1100 encased steel columns and beams. Temperature-time curves, steel temperature data, and assessed thickness/rating tables for different steel section factors.
How to request certificates: Specify which test standards and ratings are relevant to your project. Certificates are provided as PDF documents. A non-disclosure agreement may be required for proprietary test reports. Also available: Material Safety Data Sheet (MSDS), Declaration of Performance (DoP per EU 305/2011 CPR), ISO 9001 certificate, and third-party asbestos-free verification (ISO 22262-1).