This European Standard describes specific functional requirements for the renovation of pipework in existing gas infrastructures. This European Standard is intended to be applied with the requirements of EN 12007-1. This European Standard does not apply to pipework in above ground installations. This European Standard covers the various renovation technologies for gas piping in the range of sizes covering gas mains and gas service lines and is intended to be applied in association with EN 12007-1. Certain pipe networks originally for other purposes can be considered for renovation technologies to make them suitable for gas infrastructure. 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 code 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, the national legislation/regulation shall take precedence as illustrated in CEN/TR 13737. CEN/TR 13737 gives: clarification of all legislations/regulations applicable in a member state; if appropriate, more restrictive national requirements; a national contact point for the latest information.