EN ISO 6145-7:2010

Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 7: Thermal mass-flow controllers (ISO 6145-7:2009)

Publication date:   Sep 21, 2011

General information

99.60 Withdrawal effective   Dec 19, 2018


CEN/SS N21 Gaseous fuels and combustible gas

European Norm

71.040.40   Chemical analysis



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ISO 6145-7:2009 specifies a method for continuous production of calibration gas mixtures, containing two or more components, from pure gases or other gas mixtures by use of commercially available thermal mass-flow controllers.
If this method is employed for the preparation of calibration gas mixtures, the optimum performance is as follows: the relative expanded uncertainty of measurement, U, obtained by multiplying the combined standard uncertainty by a coverage factor k = 2, is not greater than 2 %.
If pre-mixed gases are used instead of pure gases, mole fractions below 10-6 can be obtained. The measurement of mass flow is not absolute and the flow controller requires independent calibration.
The merits of the method are that a large quantity of the gas mixture can be prepared on a continuous basis and that multicomponent mixtures can be prepared as readily as binary mixtures if the appropriate number of thermal mass-flow controllers is utilized.

Life cycle


EN ISO 6145-7:2010
99.60 Withdrawal effective
Dec 19, 2018


EN ISO 6145-7:2018


Adopted from ISO 6145-7:2009 IDENTICAL