Liquid nitrogen is one of the cryogenic liquids commonly used in research labs. As 'cryogenic' means related to very low temperature, it is an extremely cold material. It is liquefied under high pressure condition and can expand to a very large volume of gas. This generic chemical safety guidance describes basic prudent safety practice for handling this chemical in research labs. The principal investigator (PI) or the lab manager is responsible for developing and implementing standard operating procedures (SOPs) for the purchase, storage, and safe handling of this chemical that are specific to the PI's research.
For more information, please visit double wall cryogenic storage tank.
Contact information and areas of expertise can be found on the Contact Us page.
The vapor of liquid nitrogen can rapidly freeze skin tissue and eye fluid, resulting in cold burns, frostbite, and permanent eye damage even by brief exposure.
Liquid nitrogen expands 695 times in volume when it vaporizes and has no warning properties such as odor or color. Hence, if sufficient liquid nitrogen is vaporized so as to reduce the oxygen percentage to below 19.5%, there is a risk of oxygen deficiency which may cause unconsciousness. Death may result if oxygen deficiency is extreme. To prevent asphyxiation hazards, handlers have to make sure that the room is well ventilated when using cryogens indoors.
When transferring liquid nitrogen, oxygen in the air surrounding a cryogen containment system can dissolve and create an oxygen-enriched environment as the system returns to ambient temperatures. Since the boiling point of nitrogen is lower than oxygen's, liquid oxygen evaporates slower than nitrogen and may build up to levels which can increase the flammability of materials such as clothing near the system. Equipment containing cryogenic fluids must be kept clear of combustible materials in order to minimize the fire hazard potential. Condensed oxygen in a cold trap may combine with organic material in the trap to create an explosive mixture.
Without adequate venting or pressure-relief devices on the containers, enormous pressures can build upon cryogen evaporation. Users must make sure that cryogenic liquids are never contained in a closed system. Use a pressure relief vessel or a venting lid to protect against pressure build-up.
A full face shield over safety glasses or chemical splash goggles are recommended during transfer and handling of cryogenic liquids to minimize injuries associated with splash or explosion.
Loose-fitting thermal insulated or leather gloves, long sleeve shirts, and trousers without cuffs should be worn while handling liquid nitrogen. Safety shoes are also recommended while handling containers.
A special note on insulated gloves: Gloves should be loose-fitting so they are able to be quickly removed if cryogenic liquid is spilled on them. Insulated gloves are not made to permit the hands to be put into a cryogenic liquid. They will only provide short-term protection from accidental contact with the liquid.
The PI is responsible for SOPs specific to use of this chemical in their lab. The PI/Lab Manger is responsible for the site specific and hands-on training for the use of this chemical in their lab. Training should be directly documented in the researcher's lab notebook. On each day of training, both trainer and trainee should sign the lab notebook.
Initially, researchers should perform the procedures with the PI or senior researcher present to observe the safe handling of this chemical. Review the reagent-specific safety data sheets (SDSs). Evaluate the hazards associated with the chemical procedure and experimental setup.
If you are looking for more details, kindly visit argon dewar.
National Research Council. . Prudent Practices in the Laboratory: Handling and Management of Chemical Hazards, Updated Version. (Book)
Liquid oxygen, liquid nitrogen and liquid argon are cryogenic liquids. Their boiling temperatures are:
The sublimation point of Liquid CO2 is -109.3°F | -78.5°C.
To minimize heat transfer and sustain very low temperatures, the storage vessel must be specially designed. Storage vessels for liquid oxygen, liquid nitrogen and liquid argon are commercially available in various capacities from 350 to 13,000 U.S. gallons (1,325 to 49,210 liters) water capacity. The storage vessels may be either vertical, spherical, or horizontal depending on the site and consumption requirements for Cryogenic Bulk Tanks.
The inner vessel of the storage tank is typically designed to sustain a maximum allowable working pressure of 250 psig ( kPa). Vessels may be fabricated for higher or lower working pressures and special applications. The service pressure of the vessel is adjustable.
Only authorized and trained personnel should maintain and operate the liquid oxygen, liquid nitrogen or liquid argon storage facility and its components. Safety concerns should be reported immediately.
The following are general safe handling rules for liquid oxygen, liquid nitrogen and liquid argon:
If you want to learn more, please visit our website Lng Low Temperature Storage Tank.