prEN 1776

Scope

This document 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 document 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 document is applicable for gases of the 2nd gas family as classified in EN 437 and for hydrogen and its blends with gases of the 2nd gas family. This document 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 document is not applicable for: - raw or sour gases. - gas measurement in CNG and hydrogen fuelling stations. This document gives guidelines when installing and operating gas meters with additional functionalities (smart meters). Unless otherwise specified all pressures used in this document 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 document, EN 15001, EN 12186, EN 12279 and/or EN 1775 apply additionally, where relevant. This document 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 can 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 parts 1 and 2. CEN/TR 13737 (all parts) gives:  clarification of all legislation/regulations applicable in a member state;  if appropriate, more restrictive national requirements;  a national contact point for the latest information.