c ryogen s afety safe use of liquid nitrogen (ln2) by reece stockport departmental cryogenic safety...
TRANSCRIPT
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CRYOGEN SAFETYSafe Use of Liquid Nitrogen (LN2)
By Reece Stockport
Departmental Cryogenic Safety Advisor
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TRAINING OUTLINE
HazardsPersonal Protective EquipmentExposureSafety Procedures
General UseContainer Filling Procedure
Questions
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HAZARDS
Liquid Nitrogen (LN2) can cause severe frostbite or eye damage upon contact. Liquid nitrogen is liquefied by cooling nitrogen
gas down to (or below) its boiling point [-320ºF (-196ºC)].
Substances may become brittle upon contact with LN2 and shatter.
Expands by a factor of 700 upon vaporization
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HAZARDS (2)
May cause explosion of a sealed container
Can Cause Asphyxiation
LN2 should be used and stored in well ventilated areas!
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PPE- EYES
ANSI approved safety goggles must be worn when handling LN2. When filling your Dewar from the larger vessel a full face shield must be worn. Safety glasses do not provide adequate
protection from potential splash hazard of large quantities.
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PPE- HANDS
Cryogenic gloves are required when Dispensing from LN2 container. At any point whilst transporting and handling LN2
Limited resistance to direct exposure to liquid nitrogen (splash
resistant)
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PPE- BODY & FEET
When handling LN2 Fully enclosed shoes are required (no open-toe or canvas
shoes, sandals, or clogs) Long pants and long sleeve tops or a lab coat must be
worn (no shorts or short-sleeved shirts)
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EXPOSURE- SKIN CONTACT
Skin contact can cause severe cold burns and frostbite.
Flesh freezes very rapidly, flesh may be torn attempting to be withdrawn from object
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WHAT SHOULD I DO IF IT OCCURS? If frostbite or freezing occurs, the following steps
should be taken:
Call a first aider! Who will;
1. Flush area thoroughly with tepid water Do not apply direct heat Do not rub affected area
2. Protect area with bulky, dry, sterile dressings3. Seek medical attention4. Notify supervisor
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EXPOSURE- EYE CONTACT
Eye exposure can cause permanent irreversible damage
Delicate eye tissue can be damaged by exposure to the cold gas alone
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WHAT SHOULD I DO IF IT OCCURS? If liquid is splashed into eyes, do the following:
Call a first aider! Who will;
1. Flush with water for 15 minutes2. Seek medical attention if needed3. Notify supervisor
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EXPOSURE- ASPHYXIATION With asphyxiation, unconsciousness may happen
without warning If the person becomes dizzy, move them to a well-
ventilated area and seek a first aider Notify supervisor
Oxygen content (vol %)
Effects and symptoms (at atmospheric pressure)
11-16 Reduction of your physical and intellectual performance without the person being aware.
8-11 Possibility of fainting without prior warning.
6-8 Fainting within a few minutes, resuscitation possible if carried out immediately.
0-6 Fainting almost immediate. Fatality!
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GENERAL SAFE USE
All Activity must be Risk Assessed by a competent person!
Have a procedure when working with LN2;
procedure should include: Use only in well ventilated and low traffic areas Wear appropriate PPE LN2 should only be handled in approved containers
Avoid breathing LN2 vapors Carry containers away from body and face Do not leave open containers unattended Leave to ventilate in a corner on completion (do
not throw on floor or pour down sink)
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FILLING CONTAINERS
Double check your small Dewar has no cracks or any problems
Check the pressure relief valve is pointing away from people
Wear the appropriate PPE Take care when transporting your Dewar (DO
NOT OVER FILL)
I will now give a demonstration of the filling procedure.