A calibration gas is a gas mixture or reference gas used as a comparison standard in the calibration of analytical instruments, such as gas analyzers or gas detectors. Therefore, the calibration gas must have a precisely defined nature or composition, such as a zero gas or span gas, for example 500 ppm carbon monoxide in nitrogen.
Calibration gas
A calibration gas is a mixture of gas components used as a comparison reference during the calibration of analytical equipment, such as a gas analyzer or gas detector.
Calibration is important for all test instruments, and calibration gases are the means to establish a known response to a certified chemical component concentration.
This article looks at the key aspects to keep in mind when purchasing and using calibration gases. We will review common terminology including measurement hierarchy, traceability, recognition, and units
Calibration gas should be known
Metrology is defined by the International Bureau of Weights and Measures (BIPM) as “the science of measurement, including both experimental and theoretical determinations of any degree of uncertainty in any field What science and technology?
Consumer assurance in purchasing goods and services (such as natural gas or LNG) depends on the reliability of the measurements taken during these processes. This confidence is achieved through three fundamental activities of measurement: the definition of internationally accepted units of measurement, the realization of these units of measurement in practice, and the application of traceability chains ( link measurements to reference standards).
Forming the foundation of the metrology hierarchy are Primary Standard Materials (PSMs) created to the highest metrological quality; are independent of any other and are the definition or realization of their unit of measurement. Historically, units of measurement were often defined in relation to unique artifacts that were the legal basis of the units of measurement.
For calibration gas mixtures produced by weight, the Master Standard Material is kilograms. The kilogram is the primary mass standard for the International System of Units (SI) and is organized by the International Bureau of Weights and Measures (BIPM) in Sèvres, France.
When it comes to calibration gas standards, there are usually three levels: Primary standard gas mixture, secondary standard gas mixture, and working gas standard.
Gas mixture
The primary reference gas mixture (PRGM) is at the beginning of the traceability chain. They are the highest quality standards available for use by commercial organizations. The PRGM is prepared by direct comparison with the Master Standard Document and provides the best (lowest) uncertainty available. PRGM is commonly used by calibration laboratories and specialty gas manufacturers to establish reference values of their own internal standards through analytical comparison with PRGM.
ISO17025 is an international standard that defines “general requirements for the competence of testing and calibration laboratories”.
It is important to note that it is the laboratory that is accredited and not the reference standards that are produced.
When using ISO17025 calibration gas standards, you can be sure that the mixture has been produced using different masses of components weighed in a container and that the composition is obtained from analytical methods validated by ISO17025. receive.
