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General Safety Practices

Storage and Use

All cryogenic liquids must be stored and used in a well-ventilated area.

  • Dewars:  Dewars should be selected as non-pressurized, vacuum-walled containers. They should be equipped with a loose-fitting cap or open top and should store only small amounts of liquid.
  • Cryogenic Liquid Cylinders:  These are sealed, vacuum-walled containers, which do contain pressure up to 350 psig.  Cryogenic liquids can also be extracted from these containers.
  • Cryogenic Storage Tanks: These tanks range in size from 1900 to 4.5 x 105 L and are always pad mounted. Liquid and gas can be extracted from these containers.

 

Personal Safety

Note that eyes are the most sensitive part of body against extreme cold liquid or vapors.

To handle cryogens, it is recommended to use personal protective equipment (PPE) including full-face shield over safety glasses, loose-fitting thermal insulated or leather gloves, long sleeved shirts and trousers without cuffs. To allow quick removal in case of a spill, gloves should be in loose fit. Note that cryogenic gloves does not allow you to immerse your hand inside a cryogenic liquid, they are only designed for and provide a short-term protection, particularly for accidental contacts. While transferring cryogenic liquids, you should not wear jewellery rings watches etc.

Safety Practices

Cryogenic liquids must be handled, stored and used only in containers or systems designed in applicable standards, procedures or proven safe practices.

  • To withstand the extreme low temperatures, all the components including piping, valves etc. should be made up of appropriate materials that endure to low temperatures.
  • To prevent over-pressure, pressure relief systems should be used in piping.
  • Cryogenic containers or any part of these systems that could be valved off should be equipped with a pressure relief valve. These valves should be positioned to face forward.
  • During transfer operations including opening cryogenic containers all required PPE should be worn. People must move slowly during transfer. Note that extra care must be taken not to contact non-insulated pipes and other components.
  • Open transfers are allowed only in well-ventilated areas.
  • Never use a funnel while transferring cryogenic liquids.
  • Tongs or other similar devices should be used to immerse and remove objects from cryogenic liquids.
  • Hazard reviews are required on all newly purchased, built or modified tools using cryogenic materials. 

References and sources for information from the relevant websites and documentation of different universities, NGOs and government agencies used in the preparation of this website are provided at references.