1.1 This test method covers the determination of the total vapor pressure of air-containing, volatile, petroleum products. This test method is suitable for testing samples with boiling points above 0°C (32°F) that exert a vapor pressure between 7 and 172 kPa (1 and 25 psi) at 37.8°C (100°F) at a vapor-to-liquid ratio of 4:1. This test method is