Calibration gases are essential to ensuring gas-detecting instruments are working as they should. Calibration gas, sometimes referred to as specialty gas or calibration gas mixture, is a mixture of gases that are used to test instruments, like a hazardous gas detector, for accurate readings. Accurate readings are vital to ensure everyone's safety. The calibration mixture of gases can include carbon monoxide, carbon dioxide, nitrogen dioxide, hydrogen sulfide, methane, oxygen, sulfur dioxide, and ammonia.
Many industries utilize calibration gases to maintain safe working environments, like oil mining, manufacturing, and even first responders who test for potentially fatal gases in a rescue scenario. Since gas detection tools can test for a variety of gases, there are three categories that calibration gases fall under:
Zero Calibration Gases
Zero calibration gases are used for gas detectors that are calibrated with analyte gas structures and contain zero flammable gases. Unlike single calibration and span calibration gases, zero calibration gases do not contain the gas that the instrument detects. A common gas used in zero calibration gases is nitrogen because it is an inert gas, meaning it doesn’t react to other substances under normal circumstances.
Single Calibration Gases
Single calibration gases have a specified amount of one specific type of gas which is used to calibrate instruments that are meant to detect that particular substance. For example, a hazardous gas detector meant to detect levels of ammonia in an area would use a single calibration gas containing a known concentration of ammonia to test whether the instrument is accurate.
Span Calibration Gases
Similar to a single calibration gas, span calibration gases have known concentrations of specific gases and are used on instruments that can measure and detect those gases. For example, a gas detector that is used to measure and detect carbon monoxide, methane, and hydrogen sulfide would need to be calibrated with a span calibration gas mixture containing those three gases.
Hazardous levels of gas are dangerous and can be fatal. Regularly testing your gas-detecting instruments (see your manufacturer for specific details) ensures that your work environment stays safe.