1.1 ,This test method covers the determination of the vapor pressure of pure liquids, the vapor pressure exerted by mixtures in a closed vessel at 40 ,% ±, 5 ,% ullage, and the initial thermal decomposition temperature of pure and mixed liquids. It is applicable to liquids that are compatible with borosilicate glass and that have a vapor pressure between 133 ,Pa (1.0 ,torr) and 101.3 ,kPa (760 ,torr) at the selected test temperatures. The test method is suitable for use over the range from ambient to 623 ,K. The temperature range may be extended to include temperatures below ambient provided a suitable constant-temperature bath for such temperatures is used.