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Safety Bulletin 2017-4

In May, a gas leak was reported in a CERN installation - The causes of the accident have been identified


What happened: In May, a gas leak was reported in a CERN installation. Just over one tonne of gas was released, with potentially harmful consequences for people (danger of suffocation and circulatory problems in particular) and for the environment.


The following have been identified as causes of the accident:

  • no double ferrule in the compression fitting (1)
  • no sign that crimping has taken place
  • no tube insert
  • no compression nut (2)
  • tube poorly connected (3)

What you must do:

  • Ensure that gas installations are assembled in compliance with CERN's regulations, in particular General Safety Instruction GSI‑M‑2, “Standard Pressure Equipment”, and ensure that similar installations contain all the necessary components assembled in the correct order.
  • Select the equipment (pressure regulators, hoses, etc.) most appropriate for the intended use.
  • Remember that each connector has a specific assembly, so beware of the potential for incompatibility between the gas and the material. Refer to the catalogues of manufacturers of industrial gas equipment if you have any doubts.

Remember: Gas installations must be assembled by skilled personnel. If you have any doubts about the assembly of pressure equipment, please contact the HSE-SEE group.