Filling LN2 Tanks

Do not handle liquid nitrogen or anything in contact with liquid nitrogen without insulated gloves.

Purpose: Liquid nitrogen levels need to be carefully monitored so that cryopreserved samples are not lost.

Unlock each of the tanks with the key by the entry.
- Immediately return the key to the hook by the entry.
Put on insulated gloves. Remove the lid from the tank and set on the floor.
Use a meter stick place one end in the very bottom of the tank; hold in an upright position. Make sure the meter stick is in the bottommost part of the tank. You can check by trying to move the bottom of the meter stick in a circle, it should only be able to move in a small circle. Let it remain there for several seconds.
Remove the meter stick and gently swing in the air for several seconds. Frost will form on the end. Look at the level of the frost to determine the level of liquid nitrogen in the tank.
If the level in the tank is above 8 cm then the levels are ok, replace and lock the lid. If the level in the tank is at or below 8 cm, more liquid nitrogen is needed.
Place the hose from a large tank of liquid nitrogen well inside the small tank to be filled. Make sure it is secured well enough that it will stay in position while filling. Turn on the valve on the large liquid nitrogen tank all the way.
Wait a little while (this is a guessing game) for the liquid nitrogen to fill the tank. Turn off the valve on the big tank; wait a few seconds to make sure no liquid nitrogen is dripping from the hose. USE INSULATED GLOVES. Remove the hose from the small tank.
Check the level of liquid nitrogen in the take. Repeat this process until the level is 16 cm.