This part of ISO 22007 specifies a modulated temperature method realizing the measurement of thermal conductivity. An input of temperature deviation is less than 1 K, and a double lock-in method is applied to amplify the small temperature modulation. ISO 22007-3 specifies one of the modulated temperature methods where the phase shift is measured in the thermally thick condition, kd >> 1 [k = (ω/2α)1/2, ω: angular frequency of temperature wave, α: thermal diffusivity, and d: thickness of the specimen]. In this condition, the backing material does not affect on the phase shift results on the sensor, on which temperature wave decays exponentially. On the other hand, if kd