Mechanical Safety

All the structures brought on CERN sites must be designed and verified in such a way as to be able to withstand, without putting human life in danger and without suffering damage, the loading conditions they must be subjected to.

The demonstration of the structural soundness of a structure depends in part on its classification, but it is most often based on a set of documents which must be provided to the Safety officer a few weeks in advance of the equipment’s arrival on the CERN premises.

Examples of structures used at CERN fall in one of the following categories:

  1. a. Lifting tools – used to handle objects by attaching to a crane
  2. b. Moving equipment – while loaded, can adjust the position of the supported objected
  3. c. Pressure vessels – subjected to high pressure
  4. d. Piping systems
  5. e. Regular structures – typically fixed, supports its own weight and additional loads that do not fall in the other categories
  6. f. Others

The documents to be provided must include at a minimum the Calculation Note, which in its turn must contain at least:

  • – General description of the structural system
  • – Details of the materials of the structural components and the relevant properties (strength, elastic moduli etc.)
  • – Geometry and mass details (drawings)
  • – Applicable codes used for the structural verifications and the relevant load and resistance partial safety factors
  • – Relevant project requirements that impact the design (maximum deformations, imposed masses, temperatures etc.)
  • – List of expected load cases during transport, handling commissioning, operation, and decommissioning (with description and justification)
  • – Structural analysis strategy and details of the calculation models (modelling technique, FEA software, analysis type, element type and size, material modelling, nonlinearities, boundary conditions and contacts parameters, load application etc.)
  • – Relevant verifications for all the structural components and connections, including strength checks, stability analysis and deformations.
  • – A summary highlighting the parts with the lowest safety margins

Additional documents that might be required function of the structural classification of the equipment are:

  • – Certificate of conformance (CE certificate)
  • – Lifting test documentation (for lifting tools)
  • – Functional test (for moving equipment)
  • – Pressure and leak test documentation (for pressure vessels)