The guarded-hot-plate (GHP) method is a method used world-wide for the determination of the thermal conductivity of solid materials, especially low-conducting insulation materials, based on the direct application of Fourier’s law. It is an absolute method, which means that no reference material is needed, though regular performance checks using reference materials are highly encouraged. All measured quantities are traceable to SI-units. Applying the GHP method in accordance with existing standards, relative uncertainties in the determined values of the thermal conductivity below 2.5% are achievable. This work describes the basic theory of the measurement and is focused on difficulties and possible stumbling blocks in daily measuring practice and laboratory routine when applying the GHP method on specimens which are not or only partly covered by standards. The work explains in which cases the definition of a thermal conductivity value is not possible for a specimen and only system-related values as the thermal resistance can be attributed to a specimen. The aim of this work is to improve the measuring quality of GHP measurements for the determination of the thermal conductivity in daily laboratory operation.

防护热板 (GHP) 方法是一种基于直接应用傅里叶定律的全球范围内用于测定固体材料（尤其是低导热绝缘材料）导热系数的方法。这是一种绝对方法，这意味着不需要参考材料，但强烈鼓励使用参考材料进行定期性能检查。所有测量的数量均可追溯到 SI 单位。根据现有标准应用GHP方法，可以实现导热系数测定值的相对不确定度低于2.5%。这项工作描述了测量的基本理论，重点关注在标准未涵盖或仅部分涵盖的样本上应用 GHP 方法时，日常测量实践和实验室常规中的困难和可能的障碍。这项工作解释了在哪些情况下，不可能为样本定义热导率值，而只有系统相关的值，因为热阻可以归因于样本。这项工作的目的是提高 GHP 测量的测量质量，以测定日常实验室操作中的热导率。