ASTM D1555M-22

1.1 This standard is for use in calculating the weight and volume of benzene, toluene, mixed xylenes, styrene, ortho-xylene, meta-xylene, para-xylene, cumene, ethylbenzene, 148.9 to 176.7 °C and 176.7 to 204.4 °C aromatic hydrocarbons, and cyclohexane. A method is given for calculating the volume at a given temperature from an observed volume at an observed temperature, t °C. Table 1 lists the density in Vacuo at 15 °F and 20 °C for chemicals used to develop the relationship. Densities (or weights) “in vacuo” represent the true density (or weight) if measured in a vacuum without the buoyancy effect of air acting on the liquid. It is representative of the actual amount of product present. Densities (or weights) “in air” represent what would be measured on a scale. The difference is on the order of 0.13 %. Modern densitometers measure density in vacuo and the ASTM recommends the use of in vacuo densities (or weights).