Henric Wilkens July 2025

EP Department
Flammable Gas Safety Office

Guidelines for the declaration of a flammable gas zone

  1. EXSO (GLIMOS) refers to GSI-C2 and Guidelines C-2-0-1 and C-2-0-2 and and advice from FGSO and HSE unit (Flammable gas safety).
  2. Complete ISIEC Form at ISIEC Form on EP Safety site
  3. Based on advice from FGSO and HSE unit (Flammable gas safety) and at an early stage:
    • If gas detection needs to be installed - contact Nicolas Broca GS/ASE for quote, installation, etc. All new gas detection installations must pass an Acceptance test, organized by GS/ASE, report issued by HSE Unit;
    • Procedures and flow diagram to be drawn up by EXSO (GLIMOS).
  4. Prior to the operation with flammable gas:
    • FGSO Completes Form C-2-0-1 (Explosion Risk Assessment - checks made of the existence of procedures, gas detection etc.). Signed by FGSO and HSE Unit (Flammable gas safety);
    • FGSO Completes Form C-2-0-2, Hazardous area classification (ATEX Zone) - Carried out by FGSO - in cooperation with HSE Unit (Flammable gas safety);
    • EXSO (GLIMOS) organizes check specification of electrical equipment in the Hazardous area (ATEX Zone). Contact HSE Unit, Electrical safety;
  5. Declaration of a Flammable Gas Zone (C-2-0-3 Form) EXSO (GLIMOS) completes with copies to relevant people as on form (Nicolas.Michel.Broca@cern.ch (GS/ASE), Fire.Brigade@cern.ch (GS/FB), David.Jaillet@cern.ch (EN/MEF), Jonathan.Gulley@cern.ch (HSE Unit))
  6. Experiment operates with Flammable Gas (David Jaillet (EN/MEF) switches on)
  7. Cancellation of a flammable Gas Zone (C-2-0-3 Form) EXSO (GLIMOS) completes with copies to relevant people
  8. All relevant documents for a flammable gas installation will be kept in EDMS in the Safety Folder for the Experiment by the EXSO (GLIMOS)