ASTM C182-19 pdf download.Standard Test Method for Thermal Conductivity of Insulating Firebrick.
3. Significance and Use
3.1 The thermal conductivity of insulating firebrick (IFB) is a property required for the selection of IFB for a specific thermal performance. Users select brick to provide a specified heat-loss and cold-face temperature without exceeding the temperature limitation of the brick. This test method estab- lishes placement of thermocouples and the positioning of test samples in the calorimeter. This test method must be used with Test Method C201.
4. Apparatus 4.1 The apparatus shall consist of that described in the Apparatus section of Test Method C201 with the addition of thermocouples, drilling jig, and refractory fiber paper as described in Sections 6 and 7.
5. Test Sample
5.1 The test sample shall be selected and prepared as described in the Test Sample and Preparation section of Test Method C201.
6. Installation of Thermocouples in Test Specimen
6.1 Thermocouples—Calibrated 3 thermocouples shall be embedded in the test specimen at three points for measuring the temperature. Chromel-Alumel thermocouples shall be used for temperatures below 1400°F (760°C), and above that tempera- ture platinum-10 % rhodium/platinum thermocouples shall be used. The platinum thermocouples may also be used at the lower temperatures, but the electromotive force (emf) will not be as high as when using base-metal thermocouples. Wire of AWG 28 (0.320 mm) shall be used for making either type of thermocouple.
6.2 Installation of Thermocouples—Holes for the thermo- couple wires shall be drilled through the 4 1 ⁄ 2 -in. (114-mm) dimension of the test specimen by the use of a drilling jig so as to obtain accurate placement of the thermocouples. The three thermocouples shall be located so that the hot junction of the first couple is 0.20 in. (5.1 mm) below the hot face of the test specimen, the junction of the second at the midpoint, and the junction of the third 0.20 in. above the cold face. The thermocouple wires leading out from the hot junctions shall be located in planes parallel to the calorimeter surface. In order to have the hot junctions over the center of the calorimeter, they shall be located on an axis passing through the center of and at right angles to the 9 by 4 1 ⁄ 2 -in. (228 by 114-mm) area ofthe test specimen. N OTE 1—Insulating firebrick that cannot be prepared to this precision because of the structure of the product, should be prepared in accordance with the instructions for fireclay dense refractories.
7. Set-Up of Test Sample and Silicon Carbide Slab 7.1 Two strips of refractory fiber paper 13 1 ⁄ 2 by 1 ⁄ 2 by 0.02 in. (343 by 13 by 0.5 mm) shall be placed along the 13 1 ⁄ 2 -in. dimension of the inner guard at the outside edges, as shown in Fig. 1. Twelve strips of refractory fiber paper 2 by 1 ⁄ 2 by 0.02 in. (51 by 13 by 0.5 mm) shall be placed on the outer guard at intervals in the pattern shown in Fig. 1. These strips serve as spacers to prevent contact between the test material and the calorimeter assembly. The test specimen shall be placed centrally over the center of the calorimeter section on its 9 by 4 1 ⁄ 2 -in. (228 by 114-mm) face, the guard brick placed at the sides of the test specimen so as to completely cover the calorimeter and inner guard area, and the soap brick placed around the edge ofthe three brick so as to completely cover the calorimeter assembly. The small space between the furnace walls and the test brick assembly shall be filled with a granulated insulating firebrick.3ASTM C182 pdf download.