The upcoming Revisions of the European Safety Standard for “Tunnel Boring Machines” EN 16191 and for “Tunnel Boring Machines – Airlocks” EN 12110 as well as recent technical developments in the field of small diameter tunnelling will have a major impact on future possibilities or project design for mechanized excavation in small diameter tunnelling.

Inner diameters below 3,8m are considered small diameter tunnels. All currently existing TBM types and tunnelling methods of TBMs are used in this diameter range either in man accessible or remote operated (Microtunnelling) versions.

The purpose of the new AG  is to provide guidance for owners and designers about technical feasibilities and limitations of the different TBM / tunnelling options in light of recent developments as well as future normative requirements and restrictions.