The conditions under which auto-extinction of timber can occur are of particular importance for mass timber structures where elements of structural timber are exposed, or become exposed, during a fire. Using experiments on 95 mm cubes of timber, the sensitivity of auto-extinction to sample orientation, and an imposed flow across the surface of the sample was investigated. It was found that the variation in burning rate between the vertical and horizontal orientation was 8% but that, for samples in a vertical orientation, auto-extinction occurred at a higher value of mass loss. It was found that while the critical mass loss rate for extinction was relatively consistent in a given orientation (coefficient of variation, 16%), the variability in the time to extinction, and thus the total mass of timber consumed, was significant (coefficient of variation, 40%). Critical mass loss for extinction was linked to the square of the flow velocity at the surface of the sample.

中文翻译：

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自动灭绝时临界质量损失率的变化

木材自动熄灭的条件对于大型木结构特别重要，其中结构木材的元素在火灾期间暴露或暴露。使用 95 毫米立方体木材的实验，研究了自动消光对样品方向的敏感性，以及样品表面的强加流动。发现垂直方向和水平方向之间燃烧速率的变化为 8%，但对于垂直方向的样品，自消光发生在较高的质量损失值。研究发现，虽然灭绝的临界质量损失率在给定方向上相对一致（变异系数，16%），但灭绝时间的可变性以及消耗的木材总质量，显着（变异系数，40%）。消光的临界质量损失与样品表面流速的平方有关。