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Cryogens

safety logoCold enough to freeze soft tissue (including eyeballs)
Can displace oxygen in room leading to asphyxiation
Can explode vials and packages if used improperly
ONLY people who have been cryogen trained may use. See list of people on wall of cryogen room.

 

First time users must complete the
CRYOGEN WORKSHEET
to be listed on the cryogen wall.
(Only Available at Hopkins)

 

LN2 (liquid nitrogen)/DRY ICE (the only cryogens at Hopkins):

  1. LN2 & Dry Ice FREEZE things QUICKLY. A few seconds is enough to induce frostbite. Prolonged exposure can lead to permanent damage.
  2. LN2 & Dry Ice moves from liquid/solid state to GAS displacing oxygen in the room. Without adequate ventilation this can lead to death by asphyxiation.
  3. LN2 & Dry Ice can EXPLODE a sealed container by virtue of #2 above. This can cause serious damage to you, your equipment and your experiment.

EMERGENCY - FIRST AID

Spill or rupture = EVACUATE and call 911. Tell others around the area too.

Contact area (skin/eyes) should be flushed with luke warm water and then SEEK IMMEDIATE MEDICAL ATTENTION.
> Do not massage area, underlying tissue is brittle and this will result in more damage.

Do remove clothing from affected area so underlying circulation is improved.

In the event of any injury or emergency, notify Judy so we can fix the situation to prevent a recurrance.

PROTECTIVE EQUIPMENT

Personal

  • Full Face Shield with safety glasses
  • Heavy, Loose Fitting leather or Cryogenic Gloves
  • Long Sleeve Shirt, or Arm Protection
  • Pants should be cuff-less
  • Do not tuck pants into shoes, boots

Transporting:

  • DO NOT use an elevator (confined space). Take the stairs.
  • When in a truck or car, keep to small quantities, windows open and circulation set to outside air .
  • Do use a container designed for transport, not just anything hanging around. A brittle container will break, spilling contents.

 

LN2

CHARACTERISTICS

  • Odorless.gas above -320 degrees Fahrenheit (-196 C) Gas is slightly lighter than air. Non-flammable.

  • WILL NOT SUPPORT LIFE. Victim will not be aware of lack of oxygen when displaced by nitrogen.

  • Liquid nitrogen expands to nearly 700 times the volume of the liquid. Severe explosive and asphyxiation hazard.

HANDLING LN2

  • Always wear safety equipment, including heavy loose fitting cryogenic gloves, and eye and face protection.
  • Metals in contact with LN2 will stick to skin inducing frostbite and may be brittle.
  • High concentrations of escaping gas should not be allowed to collect in an enclosed area.
  • Avoid prolonged breathing of cryogenic "liquid" vapors .(the 'fog')
  • Avoid rough handling of liquid containers. May be brittle.
  • A cold outside jacket indicates a loss of vacuum - Contact Barbara Compton or Chris Patton
  • You are  not authorized to move LN2 cylinders. DO NOT DO SO.
  • To carry LN2 use only containers specially designed to hold liquid nitrogen - those lab foam ice buckets and insulated glass dewars (with loose lids) work great. Ask if you need one.
  • Use ONLY cryogen sample tubes in the VAPOR PHASE, NEVER in the liquid phase. All others will pop or explode.
    NEVER USE GLASS VIALS! THEY WILL EXPLODE SENDING GLASS SHARDS INTO YOU!
  • Storing LN2 in cold rooms/refrigerators/freezers will not slow down the liquid to gas conversion.
    BUT
    Storage in cold rooms will create an oxygen deficient atmosphere.
    If there is a concern regarding oxygen deficiency in these areas, oxygen deficiency alarms should be installed in these areas.
  • Never plug, restrict, or remove any relief device. Never attempt to cap or seal a venting relief device in any way.
  • Ice or frost buildup on a pressure relief valve can be removed with a damp cloth. (Wear proper Personal Protective Equipment (PPE) when removing the frost.)
  • DO NOT USE AN ELEVATOR TO TRANSPORT - Asphyxiation hazard!

READING THE GAUGES

LN2 dewer without a back light
Without a back light this type of gauge can be hard to read
LN2 dewer with a back light
Using a flashlight behind the gauges makes it possible to read
The gauge can sometimes "stick" in a more full position than the tank actually is. Gently rock the tank back and forth a few times to help seat the gauge.

TROUBLE SHOOTING LN2 TANKS - DON'T TRY IT YOURSELF - Get Barbara, x56224 instead!

 

DRY ICE - frozen carbon dioxide

>>>>> See also Shipping Haz Mat for shipping with Dry Ice.

CHARACTERISTICS

  • Colorless, Odorless, Tasteless and Nontoxic. Sublimates at -108 degrees F (-78 C). Gas is slightly heavier than air. Non-Flammable.

  • WILL NOT SUPPORT LIFE. USE ONLY IN WELL VENTILATED ROOM or GO OUTSIDE.

  • Dry Ice expands to 790 times upon sublimation.

BREATHING EFFECTS v.s. CONCENTRATION

% Vol  Effects and Symptoms
1      Slight but un-noticeable increase in breathing rate. 
2      Breathing becomes deeper – rate increases to 50% above normal. Prolonged exposure (several hours) may cause headache and exhaustion. 
3      Breathing becomes labored. Hearing ability reduced, headache experienced with increase in blood pressure and pulse rate. 
4-5    As above. Signs of intoxication after 30 minutes exposure and slight choking sensation.  
5-10   Characteristic pungent odor noticeable. Breathing very labored leading to physical exhaustion. 
       Headache, visual disturbance, ringing in the ears, confusion probably leading to loss of consciousness within minutes. 
10+    Rapid loss of consciousness with risk of death from respiratory failure.

HANDLING DRY ICE

  • Do not handle with bare hands – use leather or cryogenic gloves.
  • Avoid carrying dry ice in the passenger compartment of a truck or car.
    If this is not possible, use as little dry ice as possible.
    Ensure that the container is well insulated (though not tightly sealed) and ensure that the passenger compartment is well ventilated
    (open car windows, ensure ventilation system is set to draw fresh air from outside).
    Unload the material as soon as possible at the end of a journey.
  • Store dry ice in well ventilated areas away from direct sunlight and sources of heat.
  • Use suitable storage containers (there are commercially available insulated containers with vented seals specifically designed for storing dry ice).
  • Secure to prevent any unauthorized access. Use appropriate warning signs where necessary.
  • When opening lids to storage containers, allow a few seconds for gas to dissipate and do not lean in for longer than necessary.
  • Do not store or use dry ice in any gas tight container. EXPLOSION HAZARD!
  • Do not store dry ice in a working refrigerator or freezer
    It will sublimate at a faster rate than in an insulated storage container
    The extremely cold temperature may cause the thermostat to cut out.
  • Do not play games with dry ice.
  • Dispose of unwanted dry ice by allowing it to evaporate in a well ventilated area – it will sublime leaving no residue.
  • All users of dry ice must be are familiar with the hazards and necessary precautions. (taking this course!)