Verification regulation of thermal conductivity meter using protective hot plate method

Verification regulation for thermal conductivity tester using protective hot plate method
 
 
1. Applicability: This regulation is applicable to single specimen protective hot plate thermal conductivity meter
2. Reference materials used for verification: Reference material 1450e recognized by NIST in the United States, or reference material GSB02-3062 recognized by the National Building Materials Institute. We recommend using the former because it provides a rigorous functional relationship between thermal conductivity and temperature, while the latter only provides the thermal conductivity value at a single temperature point of 25 ℃.
3. Follow the specimen installation and software setup process in the instrument manual to operate the instrument.
4. When using the reference substance 1450e recognized by NIST for verification, one should first understand and master the usage method and precautions of the reference substance, as detailed in the attached technical data of NIST 1450e.
The following steps must be followed for the calibration of different temperature points. The inspection temperature points include mandatory temperature points and optional temperature points: mandatory temperature points include two temperature points with an average temperature of 25 ℃ and 70 ℃, while optional temperature points are determined by the user, but comply with the operating temperature range of the instrument itself and the applicable temperature range of the reference substance.
4.1 Required point 1: Measure the thermal conductivity values with an average temperature of 25 ℃ and temperature differences of 20 ℃ and 40 ℃, respectively. That is, set the corresponding hot plate temperature to 35 ℃ and cold plate temperature to 15 ℃ for a temperature difference of 20 ℃; When the temperature difference is 40 ℃, the corresponding hot plate temperature is 45 ℃ and the cold plate temperature is set to 5 ℃. Measure three times under two different conditions and take the average. According to the national standard GB/T 10294-2008 "Determination of steady-state thermal resistance and related characteristics of insulation materials - Protective hot plate method", the average test results under both conditions should be within ± 2.5% of the theoretical value of the reference substance at 25 ℃, i.e. ≤ 0.03288 ± 2.5%. When the measurement result exceeds this range, it is necessary to follow the requirements of the instrument operation manual and recalibrate before calibration.
4.2 Required point 2: Measure the thermal conductivity values with an average temperature of 70 ℃ and temperature differences of 20 ℃ and 40 ℃, respectively. That is, set the corresponding hot plate temperature to 80 ℃ and cold plate temperature to 60 ℃ for a temperature difference of 20 ℃; When the temperature difference is 40 ℃, the corresponding hot plate temperature is 90 ℃ and the cold plate temperature is set to 50 ℃. Measure three times under two different conditions and take the average. According to the national standard GB/T 10294-2008 "Determination of Steady State Thermal Resistance and Related Characteristics of Thermal Insulation Materials - Protective Hot Plate Method", the average test results under both conditions should be within ± 2.5% of the theoretical value of the reference substance at 25 ℃, i.e. ≤ 0.03774 ± 2.5%. When the measurement result exceeds this range, it is necessary to follow the requirements of the instrument operation manual and recalibrate before calibration.
When it is necessary to calibrate other temperature points, refer to the steps in 4.1 and 4.2. For the thermal conductivity values of other temperature points, please refer to the attached technical data of NIST 1450e.
5. When using the reference substance GSB 02-3062 recognized by the National Building Materials Institute for calibration, one should first understand and master the usage method and precautions of the reference substance, as detailed in its technical data.
When using this reference substance for calibration, only a single temperature point with an average temperature of 25 ℃ needs to be calibrated. Please follow the following instructions.
Measure the thermal conductivity values with an average temperature of 25 ℃ and temperature differences of 20 ℃ and 40 ℃, respectively. The corresponding hot plate temperature is set to 35 ℃ and cold plate temperature is set to 15 ℃ for a temperature difference of 20 ℃; When the temperature difference is 40 ℃, the corresponding hot plate temperature is 45 ℃ and the cold plate temperature is set to 5 ℃. Measure three times under two different conditions and take the average. According to the national standard GB/T 10294-2008 "Determination of Steady State Thermal Resistance and Related Characteristics of Thermal Insulation Materials - Protective Hot Plate Method", the average test results under both conditions should be within ± 2.5% of the theoretical value of the reference substance GSB 02-3062 at 25 ℃, that is, ≤ 0.03328 ± 2.5%. When the measurement result exceeds this range, it is necessary to follow the requirements of the instrument operation manual and recalibrate before calibration.