GB/T 19687-2005 in English

《GB/T 19687-2005闭孔塑料长期热阻变化的测定 实验室加速测试方法》由TC191（全国绝热材料标准化技术委员会）归口，主管部门为中国建筑材料联合会
本标准根据切片和尺寸因子规定了两种方法来测定含填充气体的闭孔塑料（一般90%）因为扩散而引起的随时间而变化的热阻。用标准方法来测试热阻值，方法A是对放置在受控温度环境下的薄片时间进行定期测试热阻的方法。此试验方法结合数值处理可以退出大厚度材料热阻随时间变化而变化的函数关系。方法B提供了一个无贴面闭孔塑料的设计寿命（25年或更长）期内热阻的测试方法。这个方法目前只适用于无贴面的均质材料。对于这个方法，如果材料的核心和表面所取得的试件在初始厚度方向上的热阻以及热阻随时间的变化小于10%就可以认为样品材料是均匀的。通常有自然表皮或密度有正常变化的样品可以被认为是均匀材料。

Scope

This standard specifies two methods to determine the time-dependent thermal resistance of gas-filled closed-cell plastics (typically 90%) based on slices and size factors. Standard methods are used to test the thermal resistance value. Method A is a method for periodically testing the thermal resistance of a sheet specimen placed in a controlled temperature environment. This test method combined with numerical processing can deduce the functional relationship of the thermal resistance of large thickness materials as a function of time. Method B provides a test method for the thermal resistance of unfaced closed-cell plastics over the design life (25 years or more). This method is currently only applicable to homogeneous materials without veneers. For this method, a sample material can be considered homogeneous if the thermal resistance of the specimen in the initial thickness direction and the change in thermal resistance with time are less than 10% for the core and surface of the material. Typically samples with a natural skin or normal variation in density can be considered homogeneous materials.