scope:

NEN-EN 1776 specifies functional requirements for the design, construction, testing, commissioning/decommissioning, operation, maintenance and, where appropriate, calibration, together with suitable documented provisions for all new gas measuring systems and any major changes of existing systems. This European Standard also specifies accuracy classes of measuring systems and thresholds applicable to these classes. Demonstration of compliance is achieved through the selection, installation and operation of appropriate measurement instruments, together with suitable documented provisions for calculations. Examples of demonstration of compliance are provided for each accuracy class; however, they are not prescriptive solutions. This European Standard is applicable for gases of the 2nd family as classified in EN 437. It is also applicable for treated non-conventional combustible gases complying with EN 437 and for which a detailed technical evaluation of the functional requirements (such as injected biomethane) is performed ensuring there are no other constituents or properties of the gases that can affect the metrological and physical integrity of the measuring systems. This European Standard can also be used as a guideline for 1st and 3rd family gases as classified in EN 437; however additional considerations should be taken with regard to the different constituents and physical characteristics of the gas family. This European Standard is not applicable for raw or sour gases. This European Standard is not applicable for gas measurement in CNG filling station. This European Standard gives guidelines when designing, installing and operating gas meters with additional functionalities (smart gas meters). Communication protocols and interfaces for gas meters and remote reading of gas meters are outside the scope of this European Standard and are covered by the appropriate parts of EN 13757, which provide a number of protocols for meter communications. Supervisory control and data acquisition protocols (SCADA) are also not covered by this European Standard. Unless otherwise specified all pressures used in this European Standard are gauge pressures. For associated pressure regulating systems the requirements of EN 12186 and/or EN 12279 apply. For requirements on design, housing, lay-out, materials for components, construction, ventilation, venting and overall safety of gas measuring systems within the scope of this European Standard, EN 15001, EN 12186, EN 12279 and/or EN 1775 apply additionally, where relevant. This European Standard specifies common basic principles for gas infrastructure. Users of this European Standard should be aware that more detailed national standards and/or codes of practice may exist in the CEN member countries. This European Standard is intended to be applied in association with these national standards and/or codes of practice setting out the above mentioned basic principles. In the event of conflicts in terms of more restrictive requirements in national legislation/regulation with the requirements of this European Standard, national legislation/regulation takes precedence as illustrated in CEN/TR 13737-1 and CEN/TR 13737-2.