The article presents experimental studies of typical Finnish highly insulated (HI) envelopes with thermal resistance values (R value) for the wall and roof inside the ventilation cavity between 7.7 and 8.1 m²K/W and 13 m²K/W, respectively. The conditions in the ventilation cavities were studied by using typical and increased R values for the exterior part of the cavity, which were 0.18 m²K/W and 1.57 m²K/W in the walls, and 0.13 m²K/W and 2.13 m²K/W for the roof. With higher exterior R values of 1.57 m²K/W and 2.13 m²K/W, the cavity temperature increased only after closing the inlet gap of the cavities. If the cavity inlet was closed, the restriction of the outlet gap from 20–25 mm to 10 mm had no significant effect on the temperatures. A closed ventilation inlet resulted in increased absolute humidity in the cavity, which indicates that the restriction of cavity ventilation should be made with care to avoid impairing the drying-out ability. The computational analysis showed that the optimal air change rates in the wall and roof cavities of HI structures were 4–40 1/h and 20 1/h, respectively. The conventional 22-mm-thick wood cladding enables safe cavity conditions in HI walls if the vapor barrier is vapor tight and other moisture sources are low. A lower heat flux and additional heat loss caused by cloudless sky at night support the observation that HI roofs have a higher moisture risk. In HI roofs, a conventional exterior R value of 0.13 m²K/W should at least be increased to the range of 0.3–0.4 m²K/W, which is achieved, for example, by a 20-mm-thick mineral wool board under the roofing. The use of mold-resistant materials in the ventilation cavity is recommended to mitigate the possible ramifications of the moisture behavior of HI roofs.

本文介绍了典型的芬兰高度隔热（HI）信封的实验研究，该信封在通风腔内的墙壁和屋顶的热阻值（R值）分别在7.7和8.1 m ² K / W和13 m ² K / W之间。通过使用腔室外部的典型R值和增加的R值研究通风腔中的条件，R值分别为壁中的0.18 m ² K / W和1.57 m ² K / W，以及壁中的0.13 m ² K / W和屋顶为2.13 m ² K / W。具有较高的外部R值1.57 m ² K / W和2.13 m ²以K / W计，仅在关闭型腔的入口间隙之后，型腔温度才会升高。如果关闭腔体入口，则将出口间隙限制为20–25 mm至10 mm对温度没有明显影响。封闭的通风口会导致空腔中绝对湿度增加，这表明应谨慎限制空腔通风，以免削弱干燥能力。计算分析表明，HI结构的墙体和屋顶空腔中的最佳换气率分别为4–40 1 / h和20 1 / h。如果防潮层是不透蒸汽的，而其他湿气源很低，则传统的22毫米厚的木质砌面可在HI墙中提供安全的空腔条件。夜间无云的天空导致的较低的热通量和额外的热损失支持了HI屋顶具有较高湿气风险的观察。在HI屋顶中，常规外观R值0.13 m ² K / W至少应增加到0.3-0.4 m ² K / W的范围内，例如，可以通过在屋顶下使用20毫米厚的矿棉板来实现。建议在通风腔中使用防霉材料，以减轻HI屋顶防潮性能的可能影响。