Abstract
The assessment of the uncertainty in realizing the freezing point of aluminum, which is one of the temperature fixed points defined in the ITS-90, is presented. The type A uncertainty was obtained from the repeated measurements and the type B uncertainty was estimated from various corrections such as those for self-heating of the thermometer, surroundings pressure, hydrostatic pressure effect, surroundings temperature, temperature distribution in the cell, and impurity effect of the metal. The combination of those two types of uncertainty gives a combined standard uncertainty of 0.44mK.
