Characterising the risk of the fire spread in informal settlements relies on the ability to understand compartment fires with boundary conditions that are significantly different to normal residential compartments. Informal settlement dwellings frequently have thermally thin and leaky boundaries. Due to the unique design of these compartments, detailed experimental studies were conducted to understand their fire dynamics. This paper presents the ability of FDS to model these under-ventilated steel sheeted fire tests. Four compartment fire tests were modelled with different wall boundary conditions, namely sealed walls (no leakage), non-sealed walls (leaky), leaky walls with cardboard lining, and highly insulated walls; with wood cribs as fuel and ISO-9705 room dimensions. FDS managed to capture the main fire dynamics and trends both qualitatively and quantitatively. However, using a cell size of 6 cm, the ability of FDS to accurately model the combustion at locations with high turbulent flows (using the infinitely fast chemistry mixing controlled combustion model), and the effect of leakage, was relatively poor and both factors should be further studied with finer LES filter width. Using the validated FDS models, new flashover criteria for thermally thin compartments were defined as a combination of critical hot gas layer and wall temperatures. Additionally, a parametric study was conducted to propose an empirical correlation to estimate the onset Heat Release Rate required for flashover, as current knowledge fails to account properly for large scale compartments with thermally thin boundaries. The empirical correlation is demonstrated to have an accuracy of ≈ ± 10% compared with the FDS models.

对非正式居住区火灾蔓延的风险进行表征的能力取决于了解边界条件与正常居民区明显不同的车厢火灾的能力。非正式的定居住宅经常具有热薄和漏水的边界。由于这些隔室的独特设计，进行了详细的实验研究以了解它们的燃烧动力学。本文介绍了FDS对这些通风不良的钢板防火测试进行建模的能力。用不同的墙边界条件模拟了四个隔室的火灾测试，即密封墙（无泄漏），非密​​封墙（泄漏），带纸板衬里的泄漏墙和高度绝缘的墙；配有木制婴儿床作为燃料和ISO-9705房间尺寸。FDS设法从定性和定量方面捕获了主要的火灾动态和趋势。但是，使用6 cm的像元大小，FDS能够准确模拟高湍流位置处的燃烧（使用无限快速化学混合控制的燃烧模型）的能力以及泄漏的影响相对较差，这两个因素都应进一步研究使用更细的LES滤波器宽度。使用经过验证的FDS模型，将热薄隔室的新闪络标准定义为临界热气层和壁温的组合。此外，进行了一项参数研究，提出了一种经验相关性，以估算闪络所需的开始放热速率，因为当前的知识未能正确解释具有热薄边界的大型隔室。