Cryogenics Standard

Introduction

Cryogenic liquids (argon, nitrogen, helium, hydrogen and oxygen) and certain other liquefied gases are at extremely low temperatures (-60/C to -266/C). Very small amounts of these liquids produce large amounts of gas. Consult the product's MSDS for specific guidelines regarding health and safety information, personal protective equipment and emergency recommendations.

Safety precautions that must be taken with compressed gases also apply to cryogenic liquids (see compressed gas standard). There are, however, additional precautions necessary when dealing with cryogenic materials.

Contact with cryogenic materials can rapidly freeze and destroy skin tissues. If exposed:

Contact a physician immediately.
Remove all clothing that may restrict circulation to the frozen area.
Flush affected area with warm, not hot, water. Water temperature should be between 40/C- 46/C. Do not use dry heat.
Do not rub frozen body parts, before or after warming.
Keep patient warm and resting.
Cover thawed body part with dry sterile gauze and large, bulky protective clothing.
Do not allow patient to drink alcohol or smoke.

Storage

Cryogenic liquid containers are specially designed to reduce heat loss. This design consists of an inner container and an outer casing, which are separated by a vacuum and special insulation. This construction makes cryogenic containers more fragile than other compressed gas cylinders. For this reason cryogenic containers must be handled with extreme care:

Use dollies for moving cryogenic containers. Avoid rolling containers by holding the neck as it is the main support for the inner portion of the container.
Keep containers clean. Avoid contaminating them with materials which may create hazardous conditions upon contact with the cryogenic fluid or gas.
Report all leaking or improperly set relief valves, as well as safety valves with broken seals or with any frost, ice formation, or excessive corrosion to the supplier.
Remove the container to a remote location and contact the supplier if plugs of ice or foreign material develop in container vents or opening. Do not attempt to remove the plug.
Vent containers with an approved safety device which permit excess gas to escape.
Label containers clearly.
Avoid heating or welding containers which contain a cryogen.
Do not store oxygen with any other gases except gaseous nitrogen or gaseous carbon dioxide.
Do not store liquid nitrogen with helium, hydrogen or oxygen.

Personal Protective Equipment

Use protective gloves when any material that comes in contact with cold liquids and their vapours is being handled. Gloves should be loose fitting, so that they can be removed quickly if liquids are spilled into them.
Wear chemical safety goggles and a face shield.
Cuffless trousers should cover the top of and remain outside of boots or leather work shoes.

General Safety Precautions

Use and store cryogenic materials only in well ventilated areas. Cryogenic gases are capable of displacing air necessary for respiration and causing asphyxiation.
Never allow any unprotected part of the body to touch uninsulated pipes or vessels that contain cryogenic fluids.
Use tongs to withdraw objects immersed in a cryogenic liquid.
Perform operations slowly to minimize boiling and splashing when charging a warm condenser or when inserting objects into a cryogenic liquid.
Remove all combustible materials from the area, especially oil or gasses when handling liquid oxygen. NO SMOKING signs should be posted.
Avoid wearing clothing or jewelry (watches, rings, etc.) which may trap a cryogenic fluid close to the skin.
Change and air all clothing that has been splashed with liquid oxygen immediately. Material may absorb pure oxygen and become highly flammable.
Immediately evacuate any area in which there is an uncontrolled release of cryogenic material.
Common materials such as carbon steel, plastic, and rubber may become brittle or fracture after contact with cryogenic liquids.