Liquid nitrogen

Liquid nitrogen is available as a self-serve item outside Science Stores. Please let us know if you are unsure how to dispense liquid nitrogen or if the dewar is empty. If empty, the dewar will make a high pitched noise.

Safety

• It’s very cold (-196 °C) and can cause severe frostbite.
• It can cause asphyxiation as nitrogen gas displaces oxygen in air (expansion rate is 1:694 so a small amount of liquid generates a lot of gas). Nitrogen is odourless, colourless and tasteless, so asphyxia can occur without any sensation or prior warning.

Liquid N2 SDS

Cryogens (liquid nitrogen) Safety Presentation

Avoid frostbite by wearing gloves and a face shield during dispensing. These are available next to all Science Stores dewars. Closed-toed shoes are also necessary, but we don’t provide those.

To avoid asphyxiation, dewars should never be filled in enclosed spaces. Always leave the door to the room open when dispensing and never enter a room if the oxygen sensor alarm is flashing. If you need to move a dewar between floors, never travel with it in an elevator – take the stairs.

Dispensing instructions

Before dispensing, make sure you’re wearing gloves and a face shield. Place your dewar on the floor and place the delivery hose into it to minimize splashing. Stand back from the receiving dewar and slowly open the lever valve. Once the dewar is full, close the lever valve and record how much liquid nitrogen was dispensed, based on the size of your dewar.

It is normal for dewars to vent gas from time to time, but let us know immediately if it seems to be venting abnormally.