ASHRAE手册中关于空域热阻的表格指出，这些数值仅适用于由平面、光滑、平行且无空气泄漏的表面限定的均匀厚度的空域。其他文本声明强调，在实际、非理想情况下使用计算阻力时需要谨慎，并建议对多个反射空域结构进行测试。本文介绍了这些试验的结果。数据是在一个大型垂直校准热箱中小心安装在框架构件之间的商用反射隔热材料上获得的，因此模拟了墙壁应用。通过平行路径计算，根据测量数据得出绝缘腔的热阻。结果发现，与测量数据相比，使用ASHRAE手册数据计算的电阻平均夸大了热阻146%（几乎是2 1/2倍）。因此，在使用计算数据时应继续谨慎。 引文:ASHRAE Transactions，1983年，第89卷，pt。新泽西州大西洋城1B号

The ASHRAE Handbook table on thermal resistances of airspaces notes that the values apply only to spaces of uniform thickness bounded by plane, smooth, parallel surfaces without air leakage. Additional text statements emphasize the need for caution when applying, calculated resistances to practical, nonideal situations and recommend that tests be conducted for multiple reflective airspace constructions.This paper presents results of such tests. Data were obtained on commercially available reflective insulations carefully installed between framing members in a large vertical calibrated hot box, thus simulating a wall application. The thermal resistance of the insulated cavity was derived from measured data using a parallel path calculation. It was found that resistances calculated using ASHRAE Handbook data overstated the thermal resistance an average of 146% (almost 2 1/2 times) compared to the data obtained from the measurements. Thus, continuing caution in the use of calculated data is indicated.