Calibration Gas, also called calibration gas mixture, is generally a compressed mixture of gases or gaseous components. Calibration gases are used as comparison standards within the standardization of the many instruments. They ensure that instruments such as gas analyzers or gas warning devices read correctly. The calibration gas must be traceable to a national or international standard to be considered accurate for calibration.
Calibration gases are divided into 2 categories: zero calibration and span calibration. A zero calibration gas is a mixture that does not contain any combustible gases. Zero calibration gases are used when calibrating gas detection or gas analyzers with an analyte gas structure to which the detector does not respond. A span calibration gas is more advanced in that it is a detectable concentration of gas that is precisely compounded and used for a gas detector or analyzer.