Specify the Pressure Gauge Basis

Gauge pressure is the pressure relative to the atmospheric pressure. We use the Pressure Gauge Basis value in a units of measure (UOM) Slate to convert absolute pressure units (such as kPa and psia) to gauge pressure units (such as kPa (gauge) and psig). Typically, we assume atmospheric pressure to be 1 atm. Therefore, the default value for Pressure Gauge Basis is 1 atm (or 101.325 kPa).

However, you may want to change the atmospheric pressure to match the process conditions of the actual process plant that you want to simulate. For example, your process plant may reside at an elevation much higher than sea level, which decreases the atmospheric pressure.

We highly recommend that you update the description for your UOM Slates to indicate any change from the default Pressure Gauge Basis.

Specify the Pressure Gauge Basis

1. Open the UOM Manager.

2. Select the Slate dropdown arrow.

3. On the Open Slate submenu, select the UOM Slate that you want to change.

4. Select the Pressure Gauge Basis dropdown arrow, and then select the unit of measure (UOM) that you want to use for the atmospheric pressure.

   

5. In the Pressure Gauge Basis box, enter the value for the atmospheric pressure.

6. (Optional) Update the Description to indicate the new value for the atmospheric pressure.

   Changes to the Pressure Gauge Basis affect gauge pressure calculations throughout the entire simulation. We highly recommend that you update the Description to indicate the change so that future users are aware of the change.