Liquid Nitrogen Safety Training

8/2/2019 Liquid Nitrogen Safety Training

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Occupat ional Healt h ProgramOccupat ional Healt h ProgramSafet y Training Ser iesSafet y Training Ser ies

Safe Handling and Use ofSafe Handling and Use of

Liquid Nit rogenLiquid Nit rogen
http://en.wikipedia.org/wiki/Image:Solid_nitrogen.jpghttp://en.wikipedia.org/wiki/Image:Liquid_nitrogen_tank.JPG


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Characteristics of Liquid Nitrogen andCharacteristics of Liquid Nitrogen andassociated Hazardsassociated Hazards

Handling Liquid NitrogenHandling Liquid NitrogenLiquid CylindersLiquid CylindersStorageStoragePersonal Protective Equipment (PPE)Personal Protective Equipment (PPE)Transporting Liquid CylindersTransporting Liquid Cylinders

EmergenciesEmergencies

Safet y Training Out lineSafet y Training Out lineThis aw areness t raining is int ended for laboratory users of Liquid Nit rogen


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Nitrogen = 78% of AtmosphereNitrogen = 78% of Atmosphere

It is Colorless, Odorless, Tasteless, andIt is Colorless, Odorless, Tasteless, andNontoxicNontoxic

Boils atBoils at --320 degrees Fahrenheit (320 degrees Fahrenheit ( --196 C)196 C)

NonNon

--FlammableFlammable

WILL NOT SUPPORT LIFEWILL NOT SUPPORT LIFE

Gas is slightly lighter than airGas is slightly lighter than air

Charact er ist ics of Nit rogenCharact er ist ics of Nit rogen


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HazardsHazardsLiquid Nit rogen is ext remely cold: -320F

Can cause severe frost bi t e or eye damage upon

contactSubst ances may become brit t le upon cont act w it hliquid ni t rogen and shat t er , sending pieces f lying

On vapor izat ion, Liquid Nit rogen expands bya fact or of alm ost 700 (1 cu.ft . LN 2 = 700 cu.ft . N 2)May cause an explosion of a sealed cont ainer .Displaces oxygen and m ay cause asphyx iat ion .

Oxygen may condense on surface of LN 2Highly react ive w it h organic mat erials


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LN2 should be used and st ored in w ell-vent ilat ed areas.

High concent rat ions of n it rogen reduce t hebreat hable oxygen in t he air .

LN2 release can cause oxygen deficiency:When t ransferring betw een cont ainersFrom leaking valvesFrom liquid t ank vent ingFrom open cont ainers

Oxygen Def iciency Precaut ionsOxygen Def iciency Precaut ions


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Transporting LNTransporting LN 22 ContainersContainers

Containers must always be storedin the upright position

LN2 cylinders vary in weight andsize. They are all heavy andcumbersome

Do not roll, either vertically orhorizontally

Always use the specially designedcylinder cart when moving LN 2cylinders

If the container tips over, let it go


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Handling LNHandling LN 22 ::Transferr ing fr om Prim ary Cont ainerTransferr ing fr om Pr im ary Cont ainer

Always wear safety equipment including heavy loose Always wear safety equipment including heavy loose --fitting leather or cryogenic gloves, and eye and facefitting leather or cryogenic gloves, and eye and faceprotectionprotectionPrior to use, ensure the fittings on the regulatorPrior to use, ensure the fittings on the regulatormatch the fittings on the liquid containermatch the fittings on the liquid container

Never use unregulated adaptors on liquid containersNever use unregulated adaptors on liquid containers

Open valves slowly to minimize thermalOpen valves slowly to minimize thermal

effects and control gas escapeeffects and control gas escapeDo not fillDo not fill DewarsDewars or secondary containersor secondary containersto more than 80% of capacity; expansionto more than 80% of capacity; expansionof gases may cause pressure buildupof gases may cause pressure buildup


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Handling LNHandling LN 22 ::Bench t op Cont ainersBench t op Cont ainers

Bench top containers are utilized for small scale use in labsTransfer LN 2 only from Dewars or secondary containers,never from primary pressurized tank

Never dispense liquid into an unapproved container, suchas a Thermos bottle. It will shatter.

Transfer of LN 2 can cause splashingUtilize specialized withdrawal devices instead of pouring (LN 2 Pump)

Transfer liquid slowly to prevent thermal shock, pressurebuildup, and splashing.

Always where appropriate PPE.


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Liquid Wit hdraw al

Transfer of LNTransfer of LN 22 can cause splashingcan cause splashing

Use caution when inserting openUse caution when inserting open --ended pipes orended pipes ortubes. Cold liquid/gas may spurt through warm end.tubes. Cold liquid/gas may spurt through warm end.

Ensure that withdrawal hose is equippedEnsure that withdrawal hose is equippedwith awith a phase separatorphase separator to prevent splashingto prevent splashing

Transfer liquid slowly to prevent thermalTransfer liquid slowly to prevent thermalshock, pressure buildup, and splashingshock, pressure buildup, and splashing

Always where appropriate PPE Always where appropriate PPE


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Safe Use in LabsSafe Use in LabsWhen handling LN 2 in labs, ALWAYS REMEMBER

Only trained personnel should work with LNOnly trained personnel should work with LN 22

Have a planHave a planInform others in labInform others in labUse in well vented and low traffic areasUse in well vented and low traffic areas

Wear appropriate PPEWear appropriate PPEInstruments and withdrawal devices inInstruments and withdrawal devices incontact with LNcontact with LN 22 become extremely coldbecome extremely cold

LNLN22 should only be handled in approved containersshould only be handled in approved containersDo not transport in uncovered containersDo not transport in uncovered containers

Avoid breathing LN Avoid breathing LN 22 vaporsvapors

Carry transport containers away from body and faceCarry transport containers away from body and faceDo not leave open containers unattendedDo not leave open containers unattended


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Handling Cryot ubes

Cryot ubes used t o cont ain samples st oredunder liquid nit rogen m ay explode w it houtw arning w hen handling and t haw ing.

When thawing cryotubes,

take the following protective steps:Wear a face shield and safety goggles,whenever handling cryogenic liquid.Wear appropriate insulated gloves.Wear a buttoned lab coat and pants and closed toedshoes.

Place the cryotube in a heavy-walled container (e.g., adessicator) or behind a safety shield while thawing.


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What s w rong w it h t his pict ure?


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Different Types of LNDifferent Types of LN 22ContainersContainers

Use only cont ainers specially designed to hold liquid nit rogen

-Check w it h t he manufact urer


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Low Pressure LNLow Pressure LN 22

Container ComponentsContainer ComponentsLiquid Withdrawal ValveLiquid Withdrawal Valve

Pressure GaugePressure Gauge

-- Displays internalDisplays internal

pressure of the containerpressure of the container

Contents GaugeContents Gauge -- A float A float --type liquid leveltype liquid levelgaugegauge --indicates approximate level of liquid.indicates approximate level of liquid.

Vent Valve Vent Valve -- Primarily used in the fillPrimarily used in the fillprocess to vent the vapor space while filling.process to vent the vapor space while filling.Can be used to vent unwanted pressure duringCan be used to vent unwanted pressure during

storage and usestorage and usePressure Relief Devices (2)Pressure Relief Devices (2)Protect vessel from overProtect vessel from over --pressurizationpressurization

--ReRe--seating springseating spring --loaded relief valve releases at 22 psigloaded relief valve releases at 22 psig--Burst disk rated to protect the inner vesselBurst disk rated to protect the inner vessel


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Content Gauge on Liquid CylindersContent Gauge on Liquid Cylinders

The containerThe container contentscontents gauge is a floatgauge is a float --

type liquid level sensor that indicates thetype liquid level sensor that indicates thelevel of the liquid.level of the liquid.

The gauge is an indication of approximateThe gauge is an indication of approximatecontainer content, and should not be usedcontainer content, and should not be used

for judging thefor judging the weightweight of the container.of the container.

Cont ainers are alw ays f il led by Weight !Cont ainers are alw ays f il led by Weight !


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Pressure Relief DevicesPressure Relief Devices

The liquidThe liquid --toto --gas conversion rate is about 2.3% per day.gas conversion rate is about 2.3% per day.

Pressure will build until releasedPressure will build until releasedby the control valve.by the control valve.

Unless released, gas can build upUnless released, gas can build upto dangerous levelsto dangerous levels

Hearing a slight hiss from a LNHearing a slight hiss from a LN 22cylinder is the normal operationcylinder is the normal operation

of its pressure relief device.of its pressure relief device.LNLN22 cylinders should always be stored in well ventilatedcylinders should always be stored in well ventilatedareas.areas.Cont rary t o popular belief, st orage ofCont rary t o popular belief, st orage of LNLN22 in cold roomsin cold rooms wi l lwi l lnotnot slow dow n t he liquid t o gas conversion.slow dow n t he liquid t o gas conversion.


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Warning!Warning!Never plug, restrict, or remove any relief Never plug, restrict, or remove any relief

device.device.Never attempt to cap or seal a venting relief Never attempt to cap or seal a venting relief device in any way.device in any way.Ice or frost buildup on a pressure relief valveIce or frost buildup on a pressure relief valveshould be removed with a damp cloth.should be removed with a damp cloth.

(Wear proper Personal Protective(Wear proper Personal ProtectiveEquipment (PPE) when removingEquipment (PPE) when removingthe frost.)the frost.)


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When working with LNWhen working with LN 22 ,,

the recommended PPE includes:the recommended PPE includes:Eye ProtectionEye Protection

Full Face Shield with safety goggles is bestFull Face Shield with safety goggles is bestHeavy,Heavy, LooseLoose --FittingFitting leatherleatheror Cryogenic Glovesor Cryogenic GlovesLab CoatLab CoatLong PantsLong Pants -- cuff cuff --less to avoid spill collectionless to avoid spill collection

Closed toe shoesClosed toe shoesDo not tuck pants into shoes/bootsDo not tuck pants into shoes/boots

Personal Prot ect ive Equipm entPersonal Prot ect ive Equipm ent

(PPE)(PPE)


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EmergenciesEmergencies

If there is a large spill or rupture of a container,If there is a large spill or rupture of a container,call 911 and warn others in building.call 911 and warn others in building.

Evacuat e. There may be oxygen deficiency inEvacuat e. There may be oxygen deficiency int he area of t he spill.t he area of t he spill.

Cold burns should be immediately flushed withCold burns should be immediately flushed withtepid water or placed in a warm water bath.tepid water or placed in a warm water bath.

Notify SupervisorNotify SupervisorSeek medical evaluationSeek medical evaluation

UW Hospital and Clinics Emergency RoomUW Hospital and Clinics Emergency Room

DO NOT RUB SKINDO NOT RUB SKIN may damage tissuemay damage tissue


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Thank you for your participation.Thank you for your participation.

Your safet y is im port ant t o us.Your safet y is im port ant t o us.

FOR QUESTIONSFOR QUESTIONScontactcontact

Environment, Health and SafetyEnvironment, Health and Safety@@

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Liquid Nitrogen Safety Training