Protocol for handling liquid nitrogen tanks

Introduction

The following protocol describes how to safely transport and fill liquid nitrogen in 150- 250 L cryogenic containers on wheels.

Safety info

Protect hands with cryo gloves, long sleeve shirts, wear protection glasses and put on closed shoes (not boots where liquid can splash and trapped into) when filling liquid nitrogen from the basement. Liquid nitrogen is an extremely cold material, also in a gaseous state. 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. Cold objects may also stick to the skin and tear the flesh when you attempt to free yourself. Nitrogen gas is colorless, odorless and tasteless. It can therefore not be detected by the human senses and will be breathed as if it were air. Breathing an atmosphere that contains less than 19 percent oxygen can cause dizziness and quickly result in unconsciousness and death.

In the event of spillage of liquid nitrogen on a person

If exposed to liquid or cold gas, restore tissue to normal body temperature, 37°C, followed by protection of the injured tissue from further damage and infection. Remove or loosen clothing that may constrict blood circulation to the frozen area. Rapid warming of the affected part is best achieved by using water at 42°C. Water should under no circumstances be over 44°C, nor should the frozen part be rubbed either before or after rewarming. If a person seems to become dizzy or loses consciousness while working with liquid nitrogen, move the person to a well-ventilated area immediately. If breathing has stopped, apply artificial respiration. If breathing is difficult, give oxygen. If in doubt contact Legevakt (phone 116 117 or 113 for emergencies).

If someone get liquid nitrogen it in the eyes, call 113, wash the eyes with appropriate equipment immediately.

Ordering tanks

Filling is mainly performed by a trained person in the LN₂ container room in the Realfagsbygget building basement. Remember to fill out your name, project no, signature, liter of liquid nitrogen used in the red ”geovitenskap” binder. Full tanks should be taken to the gas storage room at the 5th floor as soon as possible after filling.

By exception order liquid nitrogen through the ordering system in BasWare PM by Anna Tran (Hildegunn Almelid, Lars Evje or Eivind Støren).

Transporting tanks

To take the tank to the basement and back up to the 5^th floor:

• Transport one tank at a time.
• Make sure someone is ready to receive the lift at the other floor. Put the tank into the lift with the sign that no-one should enter the lift towards the door, push the basement button and exit the lift. Make sure the sign is clearly visible from the door. The tank will leak over time, and there is a risk of suffocation if the lift get stuck and someone is inside with the tank.
• Someone must be at the stop floor at the same time as the lift.
• Place the metal bridge over the door step so the tank can be taken in and out of the LN₂ container room in the basement smoothly.
• When full tanks are sent in the elevator it is demanded to be two people, so one can wait at the end floor when the elevator comes. This is to prevent the elevator to move to another floor before the tank is taken out. No one must take the elevator with cryo tanks.
• Tanks that are not in use (full or not) are stored in the gas room, as this is well ventilated.