OHS026
Safe Work Procedure
Faculty/Division: Medicine
Document number
STGCL.SWP.11.1
School/ Divisional Unit: St George Clinical School
Initial Issue date
15/09/09
Current version
1.0
Current Version
Issue date
15/09/09
Next review date
September 2010
The Writing Safe Work Procedures Guideline (OHS027) should be consulted to assist in the completion of this form.
Safe Work Procedure Title and basic description
Title: Safe Work Procedure for decanting Liquid Nitrogen from Dewar
Description: This Safe Work Procedure describes how to safely decant Liquid Nitrogen from 10L Liquid Nitrogen dewar. Liquid
nitrogen is commonly used for storing material at extremely low temperature (-196°C). The objective of this procedure is to ensure
that decanting liquid nitrogen is performed as safely as possible.
Associated risk assessment title and location: STGCL.RA.11.1
Describe the activity or process
Introduction for Decanting Liquid Nitrogen: Liquid Nitrogen is classed as a Dangerous Good (Class 2.2) with the main
hazards being asphyxiation (suffocation) and Cold Burns (temperature -196°C). Before carrying out this procedure, you must be
familiar with the MSDS at a minimum. NOTE: Decanting Liquid Nitrogen is restricted to Monday – Friday 08.00 – 18.00
because of the risk of asphyxiation.
Decanting liquid nitrogen from Liquid Nitrogen Dewar
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Bring approved container/ vessel for collecting Liquid Nitrogen to the Liquid Nitrogen Lab.
Check that the Oxygen Meter is working correctly ie the oxygen meter should display a reading of ≥ 19.5%
DO NOT ENTER THE LAB IF OXYGEN METER IS ALARMING.
Do not enter the Liquid Nitrogen Lab if the ventilation is not working – to check that the ventilation is working go to adjacent
labs and check that there is movement in the streamers placed on the vents in the ceiling.
Before opening any liquid nitrogen tank/dewar, dress appropriately and wear the required personal protective
equipment (PPE) as follows:
Clothes Long sleeved clothing and trousers must be worn. Trouser legs should be worn outside footwear and should not
have cuffs.
Shoes must be solid and closed to prevent the possibility of splashes entering shoes.
Laboratory Gown
Cryogenic Gloves are required to protect the hands from extreme temperature. Note: Although gloves are worn, the
wearer must not immerse gloved hands in Liquid Nitrogen.
Neoprene (impervious) apron is required to prevent spilled liquid nitrogen becoming trapped in clothing when the liquid is
being poured or racks retrieved
Polycarbonate Full Face Shield is required to prevent injury to face / eyes from potential splashes and to protect against
injury from exploding vials
Ensure the door to the room housing the Liquid Nitrogen storage tanks is open.
Remove the lid from the empty container (NB This container / vessel must be approved for holding Liquid Nitrogen)
The 10L Dewar which contains Liquid Nitrogen but no cell lines is the only dewar to be used for the purposes of decanting
Liquid Nitrogen. All other dewars are too large.
Remove the lid from the 10L Liquid Nitrogen Dewar and place to the side on the lid of an unopened adjacent Liquid
Nitrogen Tank.
Slowly and steadily pour the required volume of Liquid Nitrogen from the 10L Dewar containing the Liquid Nitrogen into the
empty vessel to minimize boiling and spluttering and being careful to avoid any spillage.
Replace the lid of the 10L Liquid Nitrogen Dewar ensuring that it fits securely and secure the lid on the vessel that the
Liquid Nitrogen has been added to.
Return the PPE to the coat hooks / basket provided in the Liquid Nitrogen Lab for the next user.
Carry the vessel containing the Liquid Nitrogen to the Lab where it is required.
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Page 1 of 2
Safe Work Procedure
Date Effective: 01/01/2007
Uncontrolled document when printed
Current Version: 1.2, 15/08/2007
List all resources required including plant,
chemicals, personal protective clothing and
equipment, etc
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Clothes Long sleeved clothing and trousers must be worn. Trouser legs should be worn outside footwear and should not
have cuffs.
Shoes must be solid and closed to prevent the possibility of splashes entering shoes.
Laboratory Gown
Cryogenic Gloves are required to protect the hands from extreme temperature. Note: Although gloves are worn, the
wearer must not immerse gloved hands in Liquid Nitrogen.
Neoprene (impervious) apron is required to prevent spilled liquid nitrogen becoming trapped in clothing when the liquid is
being poured or racks retrieved
Polycarbonate Full Face Shield is required to prevent injury to face / eyes from potential splashes and to protect against
injury from exploding vials
A container / vessel for collecting the Liquid Nitrogen – this container must be approved & fit for this purpose.
Oxygen Meter
Mechanical Ventilation
List potential hazards and risk controls including
specific precautions required
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Hazard: Thermal Burns / frostbite due to low temperature (-196°C)
Risk Control: Long sleeved clothing and trousers must be worn. Trouser legs should be worn outside footwear and should
not have cuffs, Fully enclosed footwear. Use appropriate personal protective equipment (PPE) - lab gown, Latex gloves,
cryogenic gloves (Cuffs of Lab Gown must be outside the cryogenic gloves to prevent Liquid Nitrogen entering and coming
in contact with skin), neoprene (impervious) apron, solid enclosed shoes and a full-face shield
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Hazard: Asphyxiation( Suffocation): Nitrogen gas displaces oxygen
Risk Control: perform work with Liquid Nitrogen in well-ventilated area. Oxygen Meter monitors the level of oxygen in the
air and this meter will alarm if oxygen level decreases. Failure of the ventilation system or tank rupture can cause the
nitrogen gas concentration to rise so that symptoms of asphyxiation could occur to persons entering the room or in the
area around the room. If the oxygen meter alarm sounds you must leave the vicinity immediately and notify the
manager of this area or another senior Lab person of the issue. (See emergency procedure located under alarm
panel for further information).
List emergency shutdown instructions
If there is a failure of the ventilation system or if a tank/ valve ruptures, the concentration of nitrogen gas will rise and anyone in the
room or general area could suffer asphyxiation (suffocate). In such an instance the oxygen monitor will alarm. As the largest Tank
holds 230L of Liquid Nitrogen if there was an incident involving this tank, the gas generated would fill this volume:
230L x 682 = 156, 860L = 156 m³. As the volume of the Room is only 3.1m (L) x 2m (w) x 2.6m (h) = 16.12 m3 it is critical that:
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If the oxygen meter alarm sounds you must leave the vicinity immediately, close the door to this room (if
possible) and notify the manager of this area or another senior Lab person of the issue.
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If the alarm is caused by a tank/ valve rupture, everyone must evacuate Level 3 and remain at the assembly point
(BBQ Area) until instructed otherwise by emergency personnel. When Oxygen concentration has returned to
normal, the Oxygen alarm will cease.
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Dial 666 immediately to report the incident so that emergency services can be notified and respond.
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List clean up and waste disposal requirements
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If there is a spill of Liquid Nitrogen, the liquid will heat up to room temperature and will dissipate as Nitrogen Gas. If the
Oxygen Alarm is triggered, please leave the area immediately and notify the manager of the area or another senior Lab
person
List legislation, standards and codes of practice used
in the development of the SWP
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Liquid nitrogen MSDS from supplier
AS 1894 1997 – The storage and handling of non-flammable cryogenic and refrigerated liquids
OHS Regulation 2001
Supervisory approval, training, and review
Supervisor: Prof Michael Grimm
Signature:
Plant custodian: Prof Michael Grimm
Signature
List competency required – qualifications, certificates, licencing, training - eg course or instruction: All personnel who handle samples
in Liquid Nitrogen must be trained in this Safe Work Procedure and must be familiar with the MSDS for Liquid Nitrogen.
SWP review date: September 2010
Responsibility for SWP review: Sinead O’Reilly
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Page 2 of 2
Safe Work Procedure
Date Effective: 01/01/2007
Uncontrolled document when printed
Current Version: 1.2, 15/08/2007