Study on the damage threshold of PVC and wooden blinds under vegetation fire: PVC is more prone to deformation under low heat flux

Research background and experimental methods: The performance of building facade components in wildfires or vegetation fires has increasingly become a safety issue of concern in the field of building and home decoration materials. A study published in Fire and Materials specifically examined the fire behavior of wooden, PVC, and aluminum louvers exposed to vegetation fires. The research adopts a combination of laboratory and large-scale field experiments: the laboratory uses a cone calorimeter to evaluate the ignitability of PVC and wooden blinds, with a focus on critical ignition heat flux, ignition time, and critical flux time product (FTP); On site experiments were conducted on the EXPLORII platform to evaluate the damage suffered by three types of louvers under exposure to bushfire. The study analyzed key indicators such as heat flux, received energy, heat dose, and FTP to determine the damage threshold.

Key finding: Material sorting reverses with exposure conditions

Experimental results reveal differences in damage thresholds for louvers made of different materials.

. Aluminum louvers exhibit the strongest fire resistance, and no damage occurs when the peak total heat flux reaches 177 kW/m ². PVC louvers deform under low-intensity fire exposure, i.e. when there is no flame contact and the peak total heat flux is below 50 kW/m ². At this exposure level, the fire resistance performance of wooden louvers is better than that of PVC louvers, and no damage occurs when the total heat flux is lower than this value. However, when the flame directly contacts the louvers and forms the highest fire exposure (total heat flux above 50 kW/m ²), the previously observed trend reverses: under the same total heat flux, the damage to wooden louvers is more severe than that to PVC louvers. Blackening and burning phenomena were observed in both types of blinds. The study also evaluated the reliability of FTP as a criterion for ignition of wooden and PVC blinds.

Significance for the polymer additive industry

From the perspective of building and home decoration materials, this study provides quantifiable experimental evidence for the performance boundary of PVC profiles under fire exposure.

. PVC louvers deform when there is no flame contact and the total heat flux is below 50 kW/m ², indicating that the heat resistance and dimensional stability of PVC profiles are design parameters that need to be focused on in building facade applications. For PVC profile formulations, the design of weather resistant and stable systems is not only related to the selection of antioxidants and light stabilizers for long-term outdoor use, but also involves the behavior of materials under heat exposure conditions. The critical ignition heat flux, ignition time, and FTP used in the study can provide reference for the detection and evaluation of fire resistance performance of building materials. It should be pointed out that this study focuses on the damage threshold of louvers in vegetation fire scenarios, and does not involve the specific design of polymer additive formulations or weather resistant stabilization systems. Therefore, it cannot directly derive conclusions about the role of antioxidants or light stabilizers in them. However, research suggests that the performance of PVC building materials in actual fire exposure is closely related to the level of heat flux, and formula design needs to be evaluated in conjunction with the thermal environment of specific application scenarios.

Research boundaries and areas to be clarified

This study did not disclose the specific formula, additive system, or aging state of PVC louvers, nor did it discuss the influence of weather resistant stable components on fire behavior.

. The reliability evaluation conclusion of FTP as a ignition criterion is not provided in the abstract with specific results. The lack of the above information means that more targeted work is still needed from this research to the practice of the polymer additive industry, including the study of the formula performance relationship of PVC profiles under heat exposure, as well as the systematic evaluation method of building facade components in fire scenarios.

Information source:Study of Damage to Shutters Exposed to a Vegetation Fire: Definition of Vulnerability Thresholds， Organized by Herun Chemical.