Development of validated test methods and requirements for measuring devices intended for measuring NG/H2 mixtures Building on existing results from previous and ongoing projects such as, for example, NewGasMet[[https://newgasmet.eu/]] or Decarb[[https://www.euramet.org/research-innovation/search-research-projects/details/project/metrology-for-decarbonising-the-gas-grid/?tx_eurametctcp_project%5Baction%5D=show&tx_eurametctcp_project%5Bcontroller%5D=Project&L=0&cHash=68727f268894f4b2afd6c2cd62e69051]], or the technical documents by EURAMET, experimental data from lab tests is necessary to validate technical and metrological requirements for measuring devices.Proposals should develop validated test methods and requirements on existing measuring devices used in the gas distribution and transmission networks, that will result, among others, in the definition of hydrogen limits and tolerances for currently used measuring devices. The measuring devices to be considered should include, at least, but not limited to gas meters, volume conversion devices, pressure transmitters and transducers, and quality analysers.Proposals should:Define the test condition range for the measuring devices that will be tested: temperature, pressure, total gas mixture flowrate, etc. based on the expected in-field conditions (transportation and/or distribution networks). Hydrogen percentages should cover the range between 0% to 100% vol;Select the characteristics of the tested measuring devices. Particularly, the project should define specific criteria for the selection of: Flow measuring devices that will be tested such as the type of gas meters and related size (maximum flowrate);Quality analysers, including but not limiting to gas chromatographs;Pressure transmitters and transducers;Any other measuring devices included in the project. The requirements for accuracy and metrological traceability of reference measuring equipment should be identified to test the measuring devices addressed in the project;Define a coherent methodology and proper tests programs (i.e. protocols) with the aim of identifying hydrogen limits and tolerances for the measuring devices indicated in the project. Particularly, the tests should consider different hydrogen percentages in the Natural Gas mixture in both stationary (fixed hydrogen concentration) and dynamics (variable in time hydrogen concentration) conditions;Perform testing activities based on the protocols designed. Testing of measuring devices should be performed in at least two laboratories and/or test centres to ensure the requirements of the developed procedures;Evaluate the impacts on the measuring devices in order to provide indication for further technical requirement, for example, but not limited to, the evaluation of the impact of hydrogen on the current recognised algorithms used for calculation of compressibility factor Z (EN ISO 12213, part 1 to 3) and their suitability for metrological purposes;Provide recommendations and dissemination for updating and/or development of new standards at international level. Recommendations should be provided on the following points, at least to European and National gases and metrology associations: Development and validation of technical and metrological requirements: In consideration of test results from the previous activities, development, validation and conformity assessment of technical and metrological requirements for measuring devices is needed to assure compliance of the currently used systems according to the requirements defined by standards or law for safety and process control in hydrogen technologies (as MID, OIML and other applicable metrological rules). Definition of limits and tolerances for measuring devices: Experimental definition of hydrogen limits and tolerances for currently used measuring devices both in terms of components’ failure and degradation (i.e. safety) and metrological performances.The project should identify and target the relevant standard(s) at the scope and activities should envisage links and synergies with current research projects concerning the measure of NG/H2 mixtures, such as those of the European Metrology Programme for Innovation and Research (EMPIR[[https://www.euramet.org/research-innovation/research-empir/about-empir/]]) and European Partnership on Metrology of EURAMET. Collaboration with the activities of the Selected Research Topics SRT-v09 “Metrology for the hydrogen supply chain (Met4H2)” [[https://msu.euramet.org/current_calls/greendeal_2021/index.html]] which is expected to start in 2022, should also be foreseen. Proposals are encouraged to include a formal standardisation body within the consortium.Proposals are expected to contribute towards the activities of Mission Innovation 2.0 - Clean Hydrogen Mission. Cooperation with entities from Clean Hydrogen Mission member countries, which are neither EU Member States nor Horizon Europe Associated countries, is encouraged (see section 220.127.116.11 International Cooperation).Activities are expected to achieve TRL 4 by the end of the project. TRL of 4 is to be meant as readiness level of the test methods and requirements rather than technologyThe conditions related to this topic are provided in the chapter 18.104.22.168 of the Clean Hydrogen JU 2022 Annual Work Plan and in the General Annexes to the Horizon Europe Work Programme 2021–2022 which apply mutatis mutandis.