OIML R 144-1 • Metrological and technical requirements

A.1 General requirements

A.1.1

The CGM shall be supplied either from a gas cylinder under pressure or from a gas mixture generator.

  1. Each gas cylinder shall be identified with the following information (included as a mark, label, and/or certificate):

    • manufacturer of the gas cylinder and serial number;

    • composition of the gas mixture;

    • amount of substance of each component and the corresponding measurement uncertainty ();

    • statement about the traceability of the measurement results to accepted (inter)national gaseous measurement standards;

    • temperature limits for use and storage;

    • date of certification and expiry date;

    • name of the authority that carried out the certification;

    • the marking “calibration gas mixture”; and

    • the method of preparation: gravimetric according to ISO 6142:20013) and ISO 6143:2001.

  2. The gases obtained from the gas mixture generator using the dynamic method shall meet the requirements of ISO 6145-1:20034) and in addition the requirements of B.1.2, B.2 and B.1.1.a) concerning amount of substance, measurement uncertainty and accepted (inter)national traceability to gaseous measurement standards.

A.1.2

The composition of the CGM used for type approval and verification shall be certified as complying with the requirements of B.2 by a competent authority. The unit of volume fraction for the components to be determined shall be traceable to national, regional or international standards.

A.1.3

For all other purposes the CGMs (except those indicated in B.1.2) shall be certified by the supplier of the gases and shall be traceable to the appropriate measurement standards.

A.1.4

For testing with the purpose of determining errors, three binary gas mixtures with a volume fraction of the components to be determined, corresponding to the range points of (5 + 5) %, (50 + 5) % and (95 — 5) %, are used.

For cross sensitivity testing, the gas mixtures with the maximum content of influencing components, other than the measurand are used.

A.1.5

The material of gas cylinders shall be inert to the gases contained therein.

A.1.6

The appropriate safety regulations shall be followed when handling the gases.