Fire hazard of extruded polystyrene (XPS) thermal insulation materials has aroused public concern. In order to develop flame spread theory and the guideline for fire risk assessment of XPS, an experimental study on upward flame spread behavior and heat transfer mechanism of XPS in a vertical channel with different frontal shielding rates was conducted. Maximum temperature at the place 2 cm from XPS surface and at the center of channel first increase and then decrease as the shielding rate rises. The former is higher than the latter. Experimental value of average flame height rises as the shielding rate increases. A model for predicting the flame height is built, and the predicted results are consistent with the experimental results. Moreover, the relation between flame height and pyrolysis height under different shielding rates is obtained. The flame spread rate rises as the shielding rate increases. A prediction model of flame spread rate is established, and its prediction results are more accurate compared with those from previous models. The model also predicts that radiative heat transfer is the dominant heat transfer mode, accounting for 93% of the total heat transfer. This work is beneficial for fire risk assessment and fire safety design of building façade.

中文翻译：

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屏蔽速率对垂直通道中挤出聚苯乙烯泡沫向上火焰蔓延的影响及传热机理

挤塑聚苯乙烯（XPS）隔热材料的火灾隐患引起了公众的关注。为了发展火焰蔓延理论和XPS火灾风险评估指南，对XPS在具有不同正面遮挡率的垂直通道中的向上火焰蔓延行为和传热机理进行了实验研究。距离XPS表面2 cm处和通道中心的最高温度会随着屏蔽率的增加而先升高然后降低。前者高于后者。平均火焰高度的实验值随着屏蔽率的增加而增加。建立了预测火焰高度的模型，预测结果与实验结果吻合。此外，获得了在不同屏蔽率下火焰高度与热解高度之间的关系。火焰扩散率随着屏蔽率的增加而增加。建立了火焰蔓延率的预测模型，与以往模型相比，预测结果更加准确。该模型还预测，辐射传热是主要的传热模式，占总传热的93％。这项工作有益于建筑立面的火灾风险评估和消防安全设计。