In building fires, curtain walls, as the building's external envelope, have a fire-resistant performance that directly impacts the speed of fire spread evacuation time. While aluminum veneer curtain walls, a widely used exterior wall material, possesses inherent flame retardancy, their performance in high-temperature environments requires rigorous testing. Fire performance testing is not only a core component of product safety ratings but also a crucial line of defense for building fire safety. Missing standards in any aspect can create fatal hazards.

Combustion performance is a fundamental component of fire testing for aluminum veneer curtain walls, primarily assessing the material's inherent combustion acteristics flame propagation capabilities. According to the national standard "Classification of Combustion Performance of Building Materials Products" (GB 8624), aluminum veneer curtain walls must meet a combustion performance rating of A2 higher, meaning they are non-combustible will not sustain combustion under specified test conditions. During testing, samples undergo a vertical combustion test: the aluminum veneer is fixed in a combustion device ignited with a specified flame for 10 minutes. Observation is performed to determine if the panel burns if any dripping ignites the filter paper below. Qualified aluminum veneer panels should only show localized discoloration at the direct impact of flames, with no open flames, no ignitable dripping. For composite aluminum veneer panels (such as honeycomb aluminum veneer panels), the core material's combustion performance also needs to be tested. If a paper plastic honeycomb core is used, it must be flame-retardant treated to ensure that the overall flammability rating is equivalent.

Fire resistance testing is more closely aligned with actual fire scenarios, assessing the ability of curtain wall aluminum veneer panels to maintain structural integrity thermal insulation under sustained high temperatures. According to the "Building Curtain Wall" standard (GB/T 21086), curtain wall aluminum veneer systems must have a fire resistance rating of at least one hour. This means that after exposure to temperatures of 800-1000°C, no penetrating cracks (structural integrity failure) should appear within one hour, the temperature rise on the back-of-fire side should not exceed 140°C (thermal insulation failure). During testing, aluminum panels, along with supporting keels, are placed in a fire test furnace to simulate a fire temperature rise curve (e.g., 700°C for the first 30 minutes 925°C for one hour). While the surface coating of high-quality aluminum panels may carbonize due to the high temperature during testing, the substrate must remain rigid, the connection between the keel the panel must not loosen. The temperature of the non-fired side must be monitored using thermocouples to ensure that heat transfer is effectively blocked, thus buying valuable evacuation time.

Fire sealing performance testing is often overlooked, yet it plays a critical role in preventing the spread of fire. Improper sealing between curtain wall aluminum panels at their connections to the main building structure can easily become pathways for flames smoke. Testing standards require that these areas be sealed with a fire-resistant sealant with a fire resistance rating compatible with the curtain wall system. During testing, a sealant sample is placed between two aluminum panel specimens. After high-temperature exposure, it must not fall off, exhibit cracks larger than 3mm, effectively block flame penetration. In ition, fire-resistant sealing components must be installed at the junction of aluminum veneer panels fire-compartment partition walls. Their fire resistance must meet the requirements of the designated fire compartment, typically no less than 3 hours.

Compared to other curtain wall materials, the fire resistance advantages of aluminum veneer panels must be demonstrated through test data. For example, while stone curtain walls are non-combustible, they are prone to cracking at high temperatures typically have a fire resistance of less than 30 minutes. Glass curtain walls quickly soften shatter at high temperatures, requiring a combination of fire-resistant glass fireproofing wool to enhance their performance. Qualified aluminum veneer panels, through the synergistic effect of the material coating, maintain structural stability slow heat transfer, but their performance requires rigorous testing. Currently, some low-priced aluminum veneer panels on the market suffer from issues such as insufficient flame retardant coatings the substitution of non-flame-retardant core materials. These issues are difficult to identify d on appearance alone require verification through reports from professional testing agencies. For construction professionals, when ing aluminum veneer panels for curtain walls, three key documents must be reviewed: first, a product combustion performance test report confirming it meets the A2 rating second, a system fire resistance test report to ensure it meets the required fire resistance duration third, a compatibility test report for fire-resistant sealing materials to prevent chemical reactions between different materials from compromising fire resistance. During construction, the edges of aluminum veneer panels after on-site cutting drilling must be fireproofed, such as by applying a fire-retardant coating, to prevent exposure of the material impacting overall performance.

Fire resistance testing of aluminum veneer panels for curtain walls is essentially a "firewall" built with scientific data to strengthen building safety. With fire safety increasingly important, no company should compromise testing standards for the sake of cost. Only when every aluminum veneer panel undergoes rigorous testing every fire-resistant joint meets regulatory requirements can a curtain wall truly serve as a building's safety barrier provide its full protection against fire.