CRYOGENIC

Hazard description

Cryogenics is the science and technology of low temperatures (< -150^oC or 120K).

At room temperature, cryogens are in gaseous state. At extremely low temperatures, they are liquid.

The most commonly cryogenic fluids used at CERN are argon, helium and nitrogen. They are odourless, colourless and tasteless.

• Argon: heavier than air, boiling point 87 K (atm. pressure)
• Helium: lighter than air, boiling point 4K (atm. pressure)
• Nitrogen: heavier than air, boiling point 77K (atm.pressure)

The main hazards of these cryogens are:

• Physiological: cryogenic burns to skin and eyes, lung lesions, asphyxia
• Physical: explosion caused by over-pressurisation of a cryogenic device (malfunction of safety accessories), equipment damages due to low temperature, oxygen enrichment around cold surface
• Oxygen Deficiency Hazard (ODH)

Contact

HSE Unit expert

CERN Safety Rules and related documents

The CERN Safety documents concerning the cryogenic hazards are the following:

• General Safety Instruction GSI-M-4 : Cryogenic equipment
• Safety Guidelines SG-M-4-0-1: Cryogenic equipment

Other documents related to cryogenic hazards

• Activities in Sensitive Areas for Helium spill in Accelerators below 80K

Training courses

On the CERN’s Learning Hub

Cryogenic Safety – Awareness	Programme
Cryogenic Safety – Fundamentals (Covid-19)	Classroom
Cryogenic Safety – Helium Transfer (Covid-19)	Classroom
Portable ODH Detector/Détecteur ODH Portable	Programme
Self-Rescue Mask – Initial (Covid-19)	Classroom
Self-Rescue Mask – Refresher – Theory (Covid-19)	Programme
Self-Rescue Mask – Refresher – Practice (Covid-19)	Classroom
Self-Rescue Mask – Train the Trainer	Classroom
Self-Rescue Mask – Train the Trainer – Refresher	Classroom