Units

The Units command will bring up the Unit System dialog in which the units of each Properties can be specified. To change the individual units, click on the arrow to the right of the current unit setting. A drop down list of possible units appears. Click on the desired unit. The changes made in this dialog only affect subsequent calculations. The data in existing tables are not affected by the changes.

Multiple buttons are available for selecting default sets of unit; for example, standard SI or English units. Other sets include standard SI units with Celsius for temperature, a mixed set of SI and English units (with pressure in psia, but other units in SI), and an option to use unitless dimensions for some variables, including temperature divided by the critical temperature, pressure divided by the critical pressure, and so on.

Specific (mass) or molar properties can be selected under the ‘Properties’ section. When calculating properties of mixtures, the composition can be entered on either a molar or a mass basis, depending on the selection in the ‘Composition’ section.

Pressures can be expressed as gage pressures by selecting the ‘Use Gage Pressure’ option. The atmospheric pressure or elevation at the location of interest is required to use this option.

The units are saved with other Preferences when the Save Current Options command is issued. They are restored to a previously saved option with the Retrieve Options command, or Open command.