ASTM D4893 Standard Test Method for Determination of Pitch Volatility
9. Precision
9.1 Repeatability - Duplicate values by the same operator shall not be considered suspect unless they differ by more than 0.2 %.
9.2 Reproducibility - The values reported by each of two laboratories representing the arithmetic average of duplicate determinations shall not be considered suspect unless the values differ by more than 0.3 %.
10. Determination of Unit Heat-up Rate
10.1 The volatility test temperature should be maintained at the same level for the total duration of the test. Because this is not possible, the required temperature level should be reached within the shortest time after placing the sample into the preheated blocks. The heat-up rate is determined with a selected control pitch sample. The temperature of pitch is measured and recorded with the provided thermocouple and a separate temperature indicator (not provided). For that reason the thermocouple is introduced through the upper block after removing the closing screw and its immersion in the pitch sample is adjusted so that it is covered with pitch but does not touch the bottom of the aluminum weighing dish.
10.2 The procedure for preheating the blocks and introducing the pitch sample into the cavity of the volatility apparatus is identical to the actual volatility procedure.
10.3 The temperature of pitch should level off, that is, the temperature rise should become less than 1°C/min, within the interval not longer than 10 min after the start of the experiment. Plot time versus temperature, taking data every 2 min (Fig. 5).
11. Keywords
11.1 coaltar; pitch; volatility
