The safety standards for European Community, related to TBM, were developed by the CEN TC 151 Committee, Working Group WG4. In order to effectively choose the tunnelling machine and its auxiliary installations, technical information regarding the construction-design, together with the site constraints, is provided by the contractor. A good construction-design is fundamental for the correct choice of the tunnelling machine and thus for the entire safety of the construction site. The planning of phases and spaces is critical both for the correct work organization and for the safety of workers. A concrete segment has a weight of several tons; and the effects of a release from the erector at a considerable height inside the shield can be limited to substantial material damages only if the working positions and the safety procedures have been effectively organized. The main phases of the working cycle are contemporary even when located in different zones of the machine.