What Fire Rating Can GRC Curtain Walls Achieve? Analysis of Material Properties and Structural Optimization

The fire rating of a GRC curtain wall primarily depends on the flame-retardant properties of the material itself and the curtain wall's structural design. Conventional GRC curtain walls can achieve the Class A non-combustible standard. Through structural optimization (such as fire barriers and sealing treatment), fire integrity and thermal insulation can meet 1.0–2.0 h requirements, fully complying with the fire protection requirements for curtain walls in the Code for Fire Protection Design of Buildings (GB 50016-2014). Qinglong, as an enterprise that participated in formulating the GRC industry standard, has had its GRC curtain wall products tested by authoritative institutions, all achieving Class A fire ratings and passing fire inspection acceptance in multiple public building projects.

Flame-retardant properties of the material itself: naturally Class A non-combustible, with no flame spread or toxic smoke. The main components of GRC material are low-alkali cement, alkali-resistant glass fiber, and quartz sand, all of which are inorganic non-combustible materials. According to the Classification for Burning Behaviour of Building Materials and Products (GB 8624-2012), they naturally possess Class A non-combustible performance without the need for added flame retardants. Tested, Qinglong's GRC curtain wall panels achieve A1 class burning performance (non-combustible, with no burning droplets and no toxic smoke) and an oxygen index ≥60%, far exceeding the 32% required by the Class A standard; under high temperatures (≤600°C), although the strength of GRC material decreases, there is no collapse or falling, and structural integrity can be maintained. The GRC curtain wall of the Wuhan Han Show Theatre, in a fire simulation test, withstood 1 hour of burning at 1000°C without open flames or large-scale detachment, verifying its excellent flame-retardant performance. The non-combustible nature of the material itself is the foundation of the GRC curtain wall's fire rating, superior to organic decorative materials (such as plastic and wood).

Fire-resistant structural optimization: enhancing fire integrity and thermal insulation to meet duration requirements. The fire rating of a GRC curtain wall depends not only on the material, but also requires structural design to achieve fire integrity (preventing flame penetration) and thermal insulation (preventing heat transfer): fire barriers are installed at the horizontal and vertical divisions of the curtain wall, filled with fire-rated rock wool (thickness ≥100 mm, density ≥120 kg/m³) with a height ≥800 mm, blocking vertical flame spread; gaps between GRC components and the main structure are sealed with fire-resistant sealant with a fire resistance limit ≥1.5 h, preventing flames from penetrating through gaps; for high-rise and super high-rise buildings, fire boards (such as calcium silicate boards) are added on the inner side of the GRC curtain wall to further enhance insulation. The GRC curtain wall of the Shenzhen Pingshan High-tech Zone Comprehensive Service Center (a Luban Award project), through the triple structure of "fire-rated rock wool + fire-resistant sealant + fire board", achieves 2.0 h in both fire integrity and thermal insulation, meeting the fire protection requirements of super high-rise buildings. Improper structural design can lead to a lower fire rating; for example, without fire barriers, flames can easily spread rapidly through the gap between the curtain wall and the wall.

Key factors affecting the fire rating: component thickness, fiber type, and installation method. The thickness of GRC curtain wall panels affects fire insulation; when the thickness is ≥15 mm, the insulation effect improves significantly. Qinglong's standard curtain wall panels are ≥18 mm thick, with fire insulation performance superior to ultra-thin panels; alkali-resistant glass fiber is selected as the fiber type, whose high-temperature resistance (continuous service temperature ≤250°C) is superior to ordinary glass fiber, maintaining component strength in the early stage of a fire; when the dry-hanging installation method is used, the gaps between components and the wall must be properly fire-sealed to avoid the "chimney effect". Qinglong's dry-hanging GRC curtain wall has 100% sealant coverage, effectively blocking smoke spread. In one project, ultra-thin GRC panels (12 mm thick) were used without sealed gaps, achieving fire integrity of only 0.5 h; after optimization by Qinglong (increasing thickness to 18 mm + sealing gaps), fire integrity was improved to 1.5 h.

Testing and certification of fire ratings: verification by authoritative institutions to ensure compliance. Qinglong's GRC curtain wall products are all sent to the National Fire Product Quality Supervision and Inspection Center for testing, covering items such as burning performance, fire integrity, thermal insulation, and smoke toxicity. All indicators meet the Class A standard and fire duration requirements, and each batch of products comes with a test report. In the Hainan Changying Universal 100 Fantasy Park project, the GRC components were tested at fire rating A1, with fire integrity and thermal insulation reaching 1.5 h, and successfully passed fire inspection acceptance. For projects with high fire protection requirements, such as public buildings and high-rise buildings, the manufacturer's testing certification and past experience in fire inspection acceptance are crucial.

The fire rating of GRC curtain walls naturally possesses the Class A non-combustible advantage, and structural optimization can further enhance fire integrity and thermal insulation to meet the fire protection requirements of different projects. Qinglong, based on the flame-retardant properties of the material itself and combined with scientific structural design and rigorous testing and certification, ensures that the fire performance of GRC curtain walls meets standards. For owners and designers, the fire rating is a key indicator in curtain wall material selection; choosing a manufacturer with fire design and testing capabilities is the core guarantee for project fire compliance, and Qinglong safeguards building fire safety with professional technology.