In the future hydrogen-based economy, H2 transportation and storage needs to be safe and cost effective. Transportation and storage in the form of pressurized gas is gaining consideration since it takes advantage of existing pipeline infrastructure; according to a recent study by the major European Transmission System Operators (TSOs), there will be a gradual evolution from retrofitting of existing pipelines to construction of new ones which will result by 2040 in a total length of 22,900 km of H2 pipeline in EU, consisting of approximately 75% retrofitted existing infrastructure and 25% of new hydrogen pipelines.But hydrogen properties imply an ad hoc pipeline material selection and qualification process according to the transportation conditions. Hydrogen may embrittle pipeline materials, and can seriously affect the pipeline integrity, particularly in the presence of stress concentrators (defects).There is a lack of consistency and guidelines regarding qualification and approval of pipeline materials for H2 and H2-Natural Gas (H2NG) service; existing standards may be over-conservative, so preventing the exploitation of the full potential of both new and existing assets.Aim of the project is to develop guidelines for material selection and qualification process for safe transportation of H2 and H2NG for both new and existing pipelines. By means of state-of-the-art engineering studies and testing and adopting a Fitness for Service approach, the present project will provide info and data and guidelines for safe use of future new H2 pipelines as well as retrofitting of existing ones.Interaction with external certification bodies and international research organizations will also provide proper feedback and results dissemination.The project will deliver results in an 'operational ready' format, and in particular the Final Report will contain specific addenda designed to be suitable for direct incorporation into existing standards.