为揭示建筑装饰材料聚甲基丙烯酸甲酯(有机玻璃，PMMA)在不同放置角度下的火焰蔓延特性，通过自主搭建的小尺寸火焰蔓延实验平台，研究了宽3 cm、厚2 mm的PMMA试样在不同放置角度下的火焰蔓延特性. 结果表明，放置角度对PMMA火焰蔓延过程中热解区域及预热区长度影响很大，由15°到30°及由?60°到?75°时(顺流火焰蔓延时放置角度为正，逆流火焰蔓延时放置角度为负)，平均火焰倾角增加幅度最大. 顺流火焰蔓延的火焰长度随放置角度增加先略减小后逐渐增加，逆流火焰蔓延的火焰长度随放置角度的绝对值增加而略减小. 放置角度由0°到15°时，顺流火焰蔓延的平均速度呈跃变增长，逆流火焰蔓延的平均速度随放置角度绝对值增加而略降低.

In order to reveal the effect of placed angle on flame spread characteristics over polymethyl methacrylate (PMMA), a small-scale flame spread setup was established and then a series of flame spread experiments on PMMA samples with width 3 cm, thick 2 mm and different placed angles were carried out. The results showed that the pyrolysis zone and preheating zone length were largely influenced by placed angle through infrared image analysis. The average flame angle increased greatly when the placed angle changed from 15° to 30° and from ?60° to ?75° (for upward flame spread, the placed angle is positive, and for downward flame spread, the placed angle is negative). Meanwhile, for upward flame spread, the flame length decreased slowly and then increased with placed angle, however, for downward flame spread, the flame length decreased slightly with the absolute value of the placed angle. As for the upward flame spread, when the placed angle changed from 0° to 15°, the average flame spread speed will increase greatly. And for the downward flame spread, the average flame spread speed decreased slightly with the absolute value of the placed angle.