Gas analysers

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GAS ANALYZERS

The Laboratory of Gas Analyzers in the Amount of Substance and Electrochemistry Area of the National Metrology Laboratory is responsible for the calibration of several types of environmental and pollutant gas analyzers.

The Laboratory also performs the metrological control of exhaust gas analyzers, including the Type Approval, and Initial Verification.

The procedure for analyzers calibration is based on the comparison method by which the instrument reading is compared with the conventionally true value of the reference gas which had been subjected to analysis. The reference gas, known as Certified Reference Material (CRM) consists in binary gas mixtures in nitrogen and presents itself in different molar fractions, covering the measurement range of each type of analyzer. For each molar fraction repeatability tests are carried out, with determination of the standard deviation of the test, error and associated uncertainty. The CRM have traceability to the primary standard gas mixtures produced in IPQ.

AREAS OF EXPERTISE

The areas of expertise of the Gas Analyzer Laboratory are in the scope of calibration / metrological control of several types of gas analyzers, namely:

- Indoor air quality analyzers;
- Effluent gas analyzers;
- Exhaust gas analyzers;
- Flammable gas analyzers;
- Analyzers used in domestic gas inspection networks;
- Analyzers used in the food area.

TRACEABILITY

The mole, symbol mol, is the SI unit of amount of substance.

One mole contains exactly 6.022 140 76 x 1023 elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in the unit mol–1 and is called the “Avogadro number”.

The amount of substance, symbol n, of a system is a measure of the number of specified elementary entities. An elementary entity may be an atom, a molecule, an ion, an electron, any other particle or specified group of particles.

The calibration / metrological control traceability is done to national and international standards, guaranteed through the use of traceable equipment to the SI units and by the adoption of preparation and certification of gas mixtures methods in agreement with the applicable international standards.

The accuracy of the measurements made is proven through the participation in projects and in international comparisons, and it is demonstrated by the acceptance and inclusion in the Capacities of Measurement and Calibration (CMC) BIPM database and also with the international equivalence of measurements through the Mutual Recognition Arrangement (CIPM-MRA), for IPQ gas mixtures.

External document:

Mise en pratique for the definition of the mole in the SI