2.2.4. Thermal conductivity
Thermal conductivity coefficient is found with Hot Wire Method given in ASTM C 1113- 90 [30].
The most widely used nonsteady method is the transient hot-wire method.
A thin wire is embedded in the test material which is at room temperature before the experiment starts. The test is conducted by heating the wire electrically. Heat is released in the radial direction into the surroundings and the wire temperature climbs with a transient which is more or less steep depending on the thermal conductivity of the test medium. According to Turkish Standard TS EN 415 [31], if the thermal conductivity coefficient of a material is under the value of 0.060 kcal/m h^°C, that material is called as “thermal insulator”. If its conductivity coefficient is higher than the critical value, 0.060 kcal/m h^°C, then it is classified as “construction material”. Materials used in buildings have different thermal conductivity values. This test was performed at the temperature of 22◦C. The thermal conductivity test device and the testing process is shown in Fig. 4.