Department of Physiology
Procedure No:
PHY/SOP/RE05
Revision No:
001
Title:
Effective Date :
16/6/2010
Cryogenic Liquids
(Adopted from OSHE/SOP/GL/09)
Page:
Page 1 of 4
Safety & Health
Laboratory (Location):
Cytokine biology Lab, MD9
Prepared/Review By
Approved By
Next Review Date
Oh Chu Yun
Dr. Leung Pui Lam Bernard
16/6/2013
* Review Date = Future date for the next revision (every 3yrs)
1.0 OBJECTIVE
The objective of this SOP is to provide guidance on the safe handling of cryogenic
liquids so as to protect employees from the risk of injury and property damage.
2.0 SCOPE
This SOP is applicable to all labs under the management of Department of
Physiology.
3.0 RESPONSIBILITIES
3.1 Principal Investigators
PIs have the primary responsibility for the implementation of this SOP in their
work area. This involves:
a. Preparation, and proper storage, transfer and use of cryogenic liquids.
b. Providing appropriate PPE to employees and students where applicable.
c. Training of employees/users.
3.2 Users
Users of cryogenic liquids must:
a. Adhere to safe handling procedures
b. Wear appropriate PPE when handling cryogenic liquids
c. Attending required training sessions.
4.0 DEFINITION
Cryogenic materials: Materials that are characterized by their extremely low
temperature (-60°C to -270°C).
Department of Physiology
Procedure No:
PHY/SOP/RE05
Revision No:
001
Title:
Effective Date :
16/6/2010
Cryogenic Liquids
(Adopted from OSHE/SOP/GL/09)
Page:
Page 2 of 4
Safety & Health
Laboratory (Location):
Cytokine biology Lab, MD9
5.0 PROCEDURES
5.1 Handling
a. Appropriate personal protective equipment should be worn when handling
cryogenic liquids. This includes special cryogen thermal gloves, safety
goggles, full face shield, impervious apron or coat, long pants, and high
topped shoes. Gloves should be impervious and sufficiently large to be
readily removed should a cryogen be spilled. Watches, rings, and other
jewelry should NOT be worn.
b. Unprotected body parts should not come in contact with vessels or pipes that
contain cryogenic liquids because extremely cold material may bond firmly to
the skin and tear flesh if separation is attempted.
c. Objects that are in contact with cryogenic liquid should be handled with
tongs or proper gloves.
d. All precautions should be taken to keep liquid oxygen from organic materials;
spills on oxidizable surfaces can be hazardous.
e. All equipment should be kept clean, especially when working with liquid or
gaseous oxygen.
f. Work areas should be well ventilated.
g. Transfers or pouring of cryogenic liquid should be done very slowly to
minimize boiling and splashing. Transfer of liquid nitrogen should be done in
a well ventilated area.
h. Cryogenic liquids and dry ice used as refrigerant baths should be open to the
atmosphere. They should never be in a closed system where they may
develop uncontrolled or dangerously high pressure.
i. Liquid hydrogen should not be transferred in an air atmosphere because
oxygen from the air can condense in the liquid hydrogen presenting a
possible explosion risk.
5.2 Storage
a. Cryogenic liquids should be handled and stored in containers that are
designed for the pressure and temperature to which they may be subjected.
The most common container for cryogenic liquids is a double-walled,
evacuated container known as a Dewar flask.
b. Containers and systems containing cryogenic liquids should have pressure
relief mechanisms.
Department of Physiology
Procedure No:
PHY/SOP/RE05
Revision No:
001
Title:
Effective Date :
16/6/2010
Cryogenic Liquids
(Adopted from OSHE/SOP/GL/09)
Page:
Page 3 of 4
Safety & Health
Laboratory (Location):
Cytokine biology Lab, MD9
c. Cylinders and other pressure vessels such as Dewar flasks used for the
storage of cryogenic liquids should not be filled more than 80% of capacity,
to protect against possible thermal expansion of the contents and bursting of
the vessel by hydrostatic pressure. If the possibility exists that the
temperature of the cylinder may increase to above 30oC (86oF), a lower
percentage (i.e., 60 percent capacity) should be the fill limit.
d. Dewar flasks should be shielded with tape or wire mesh to minimize flying
glass and fragments should an implosion occur.
e. Dewar flasks should be labeled with the full cryogenic liquid name and hazard
warning information.
f. Transportation of cryogenic liquids via elevators should be accomplished by
human intervention at each floor level and while elevator is unmanned.
g. Liquid nitrogen containing equipment or containers should be stored in a
well-ventilated area with tiled flooring instead of vinyl flooring to prevent
damage to the floor.
5.3 Training
All staff using or handling cryogenic liquids must receive training which includes
hazards associated with its use, care, selection and use of protective equipment and
emergency procedures. New users of liquid nitrogen should receive instruction in its
use from experienced members of the academic or technical staff.
5.4 Personal Protective Equipment
a. Protective clothing suitable for handling these liquids shall be provided with
particular attention given to gloves and eye/face protection.
b. Dry asbestos (substitute) or dry leather gloves (when handling equipment
that has been in contact with the liquid). If gloves are worn they should be
loose fitting and easily removed.
c. Lab coat or overalls are advisable to minimize skin contact, also, wear
trousers over shoe/boot tops to prevent shoes filling in the event of a spillage.
5.5 First aid
a. Warm the affected area of the body rapidly by immersion in water not to
exceed 40oC, with body heat, or by exposure to warm air. In the event of
massive exposure, the emergency shower should be used to warm the body.
All clothing must be removed prior to showering. Maintain the affected area
of the victim at normal body temperature until medical help arrives.
Department of Physiology
Procedure No:
PHY/SOP/RE05
Revision No:
001
Title:
Effective Date :
16/6/2010
Cryogenic Liquids
(Adopted from OSHE/SOP/GL/09)
Page:
Page 4 of 4
Safety & Health
Laboratory (Location):
Cytokine biology Lab, MD9
b. Calm the victim and prevent aggravation of the injury. People with frostbitten
feet should not walk on them. Do not rub or massage the affected parts of
the body.
a. Prevent infection – use a mild soap to clean the affected area. Dressings
need to be applied if the skin is intact.
c. Flush eyes, if affected, with warm water for 15 minutes.
6.0 RECORDS
Nil
7.0 REFERENCES
Nil