In order to make sure that a gas detector instrument will detect gases in the air accurately, a calibration gas of a known concentration must be used to ensure that the gas detector is responding accurately to the amount of gas it is measuring. Although a gas detector may have been calibrated in the past, many outside factors can affect the calibration over time and therefore the detector needs to be re-calibrated often.
What is Calibration Gas
Calibration gas, also known as span gas, is a certified gas or mixtures of gases used with a gas detector. The use of a calibration gas allows for calibration of a gas detector that is used to detect the presence of toxic and combustible gases or potentially hazardous amounts of other gases.
The response of the gas detector to the calibration gas serves as the reference point to use when measuring the gas in the air. Calibration gas is available in a variety of types of gases and is available as a single gas or a multiple gas mixture. Multiple gas mixtures are most often four gas mixtures.
Selecting a Calibration Gas
When selecting a calibration gas, it’s important that the type and concentration of the gas matches the requirements of the detector being used. In addition, any accessories such as tubing, regulators or adapters must also be compatible with the device. It’s also important to ensure that the calibration gas is not expired.
It is best to choose a calibration gas that is closest to the gas or gases that is being detected. Calibration gases use should be traceable to NIST (National Institute of Standards and Technology) standards.
Gas detection equipment can include a number of devices including gas detector tubes and pump kits. A single calibration gas or pure gas, should be used with a single gas detector and a multi-gas mixture must be used with a multiple gas detector.
Why is the Use of Calibration Gas Important?
The number one reason to use calibration gas is for worker safety. Use of non-calibrated gas detectors can cause inaccurate testing and gas detection readings which can lead to unsafe work environments. The use of calibration gas ensures that the gas detection technology is working correctly and is able to detect when gases may be creating hazardous conditions.