在两个典型建筑结构的小样本复合墙体上进行了实验室规模的实验，以确定因水蒸汽压差而停止或显著减少水蒸汽传输所需的近似反向空气压差。实验使用了两个受控大气室之间的壁面样品。其中一个房间的温度和湿度接近典型夏季的温度和湿度条件，而另一个房间的温度和湿度控制在典型的室内条件下。在一系列蒸汽压差和反向空气压差下，获得了通过壁样品的蒸汽传输数据。 结果表明，如预期的那样，增加反向空气压差会降低水蒸气的透过率，对于小蒸汽渗透性和大空气渗透性的墙体材料，需要相对较小的反向空气压差。通过实验确定了阻止或显著减少水蒸气通过壁样品流动的反向空气压力，并将其与分析模型预测的空气压力进行了比较。单位:双引证:阿什雷交易，1998年，第104卷，第2部分，多伦多

Laboratory scale experiments were performed on two small sample composite walls of typical building construction to determine the approximate opposing air pressure difference required to stop or significantly reduce the transmission of water vapor due to a water vapor pressure difference. The experiments used wall section samples between two controlled atmosphere chambers. One chamber was held at a temperature and humidity condition approximating that of a typical summer day, while the other chamber was controlled at a condition typical of indoor conditioned space. Vapor transmission data through the wall samples were obtained over a range of vapor pressure differentials and opposing air pressure differentials. The results show that increasing opposing air pressure differences decrease water vapor transmission, as expected, and relatively small opposing air pressure differentials are required for wall materials of small vapor permeability and large air permeability. The opposing air pressure that stopped or significantly reduced the flow of water vapor through the wall sample was determined experimentally and also compared to air pressures as predicted by an analytical model.Units: Dual