STP (Standard Temperature Pressure): User Guide

A correction factor is often required in scientific applications when a measurement involving a gas is influenced by changes in atmospheric pressure and temperature. This application was developed with the ionization chambers used in the calibration of radiation therapy beams in mind, but the default standard reference values are very easily changed for other commercial and scientific applications.

The red buttons adjust whichever field (temperature or pressure) is currently highlighted in red. Tap the labels of the input fields to change the button context. You can also enter values directly by tapping in the text field and using the virtual keyboard.

The Reset button at the lower right reinitializes the calculator to the default standard values.

1. The correction factor is automatically calculated as you change the input values. In the example above the standard temperature has been set to the European convention of 20°C. To set your standard reference pressure and temperature preferences see column 3 to the right.

2. As an added convenience, you can also simultaneously convert between temperature and pressure units by choosing a different system of units for the input fields (e.g. °F, mmHg) and results display (e.g. °C, kPa) at the top of the screen.

3. You can change the default standards to suit your application by simply entering them here in the "info" screen by using the virtual the keyboard. For pascal units of pressure you can choose between kilopascal (kPa) and hectopascals (hPa). The entire state of the calculator is automatically saved to preferences when exiting so any values you enter here will be retained until you decide to change them.