Laboratory safety (Cryogenic safety and Chemical safety)

1. Laboratory Safety
Prepared By:-
Mr. Jay Patel

2. is responsible for quality and safety
EVERYONE

3. Why does it matter?
Safe working protects:
 You
 Other lab workers
 Cleaners
 Visitors
 Your work

4. Effects of a laboratory accident
Negligence
of laboratory safety is costly!
loss of staff confidence
loss of reputation
loss of customers
increased costs : litigation, insurance

5.  LABORATORY SAFETY
Machine Safety
Cryogenics Safety
Fire Safety
Laser Safety
Radiation Safety
Gas Cylinder Safety
Chemical Safety
Bio Safety

6. Cryogenics Safety

7. What is a cryogen?
For our purposes, a cryogenic liquid is defined as any liquid
with a normal boiling point below ‐150°C (123K).
Cryogenics is the science of ultra low temperatures.
Low temperatures are achieved by the liquefaction of gases.
The gases which are most widely used in industry and
research are helium, hydrogen, nitrogen, fluorine, argon,
oxygen and methane.
 Introduction:

8. Properties of cryogenic fluids:
Extreme low temperatures.
Large ratio of expansion in volume from liquid to gas.
Most cryogenic liquids are odourless and colourless when vaporized to
gas.
Boiling points of cryogens :
•Helium -269.9 0C
•Hydrogen -252.7 0C
•Neon -245.9 0C
•Nitrogen -195.8 0C
•Oxygen -183.0 0C
Liquid to gas expansion ratios of cryogens:
•Helium 1 to 757
•Hydrogen 1 to 851
•Neon 1 to 1438
•Nitrogen 1 to 696
•Oxygen 1 to 860

9. Potential hazards:
Potential hazards in handling cryogens are
They displace oxygen in non ventilated confined spaces causing oxygen
deficient atmosphere.
On contact with skin, they can cause frost burns due to extreme cold.
Pressure build up in the container can cause explosion.
Affects properties of materials.
A work space is considered unsafe for entry if the oxygen level falls below
19.5%.
Contact with cryogens (liquid and vapour) can cause burns similar to that
caused by high temperature thermal burns.
Cryogens can cause embrittlement of the exposed body surface because of high
water content of the human body.
Splashing of cryogens can result in permanent eye damage.

10. Cryogenics Safety
Control Measures to Mitigate Hazards Associated with Cryogens
Engineering Controls:
 Pressure Relief Valves
 Insulation
 Ventilation
Administrative Controls:
Training
 PPE (safety glasses, closed‐toe shoes)
Note on PPE…
Insulated gloves are optional, but it is highly recommended that you have them
within easy grabbing distance. When you do discover that you need gloves, you
need them NOW.

11. Warning signs of a damaged dewar or cryostat:
Continuous venting from a vent valve is not normal. It could mean there is dirt
in the vent valve or it is damaged.
Sweat or Frost at the bottom or sides of a dewar or cryostat is an indication of a
faulty or damaged vacuum jacket. If you discover a dewar or cryostat in this
state, contact sample environment.
Your responsibility:
Be Knowledgeable
 Be sure that you have all the necessary training to work with a specific piece of
equipment
 If you are unsure, DO NOT assume that you know what you are doing! Do
NOT use the equipment!
Be Aware
Be aware of when cryogens are being transferred
 Be aware of where potential locations/objects/body parts are with which the
cryogenic liquid may come in contact.

12. Storage:
Cryogenic fluids are stored in well insulated containers to minimize loss due
to boil off.
The most commonly used container for handling cryogenic fluids is the
Dewar flask.
Dewar flasks are non pressurized, vacuum jacketed vessels.
Containers for storing cryogens

13. First Aid:
In case of splash, flush the affected part
continuously under running water for at
least 15 minutes.
In case of splash in the eyes flush continuously for at least
15 minutes. Seek medical help.

14. Precautions during handling:
Keep safe distance from boiling and splashing liquid and
its issuing cold gas.
Boiling and splashing occur when charging a warm
container or when inserting objects into the liquid.
These operations must be performed slowly to minimize
boiling and splashing.
Any unprotected part of the body must never be allowed to
touch uninsulated pipes or vessels containing liquefied
gases.
The extremely cold metal can stick fast and tear the flesh,
if an attempt is made to withdraw from it.

15. Liquefied gases must be transported only in suitably
insulated containers that provide means for the escape of
gas as liquid evaporates. Never plug the outlet of such
containers.
When pouring liquefied gases from one container to
another, the receiving container must be cooled gradually
to prevent thermal shock.
The liquid must be poured slowly to avoid spattering.
A discharge tube must be used when it is not safe or
convenient to tilt the container or to remove liquid from
large 50-or 100-litre containers.

16. Cryo flask for handling liquid nitrogen

17. Portable trolleys must be used for moving large
containers of cryogens.

18. Cryogenic containers must not be dropped or tipped on their sides.
Frost spots may appear in case of loss of insulating vacuum. A vessel in
this condition must be removed from service. Repairs must be handled by
the manufacturer.
Prevent the entry of liquid cryogen inside the glass vials while inserting
the same inside the container. As later the liquid can expand causing the
explosion of the vial.
Tongs must be used to withdraw objects immersed in liquid.

19. Personal Protective equipment

20. Chemical Safety

21. Chemicals are a hazard
Hazard: Potential to cause harm
Risk: Likelihood that harm will arise
 Perception of risk is critical
Risk depends on exposure
Minimise EXPOSURE & reduce the RISK!

22. Hazardous Substances
Physico-chemical Hazards
 include flammable, explosive and oxidising
Toxicological Hazards
 include toxic, carcinogenic, mutagenic, harmful, irritant,
corrosive and sensitising
Environmental Hazards

23. Flash-Point
 The flammability of Liquids defined by its flash-point
The lowest temperature at which a fuel-air
mixture present above the surface of a liquid will
ignite if an ignition source is introduced
 21-55 0C ~ Flammable
 <21 0C ~ Highly flammable
 < 0 0C ~ Extremely flammable

24. Safety precautions
Do not work alone in the
laboratories particularly when
performing hazardous
procedures.
Do not perform unauthorized
experiments.
Plan appropriate procedures
and the positioning of all
equipment before beginning
any experiment.

25.  Avoid storing any chemical above eye level
 Don’t store incompatible chemicals together
 Don’t store chemicals near sources of heat or sunlight
 Don’t store chemicals in the hoods or acids on metal shelves
 Avoid storing anything on the floor, especially glass bottles
The “Don’ts” of Chemical Storage!

26.  Read Chemical Labels
Every container of chemicals is labeled by the
manufacturer.
The label will tell you
 Name of chemical
 Name, address and emergency phone number of
manufacturer
 Physical and health hazards
 Precautionary measures
 First-aid instructions
 Proper handling/storage instructions

27. Typical Precautionary Measures
on a Label
 Do not breathe vapors
 Use in well-ventilated areas
 Keep container closed when not in use
 Avoid contact with skin
 Wash thoroughly with soap and water after handling
 Keep away from sparks, heat, and flame
 Do not store near combustible materials
 Store in tightly closed container
 Remove and wash contaminated clothing promptly
 Keep from contact with clothing and other
combustible materials

30. Wear appropriate personal protective equipment, a laboratory apron or
coat, safety glasses and toe covered footwear at all times in the laboratory.
Wear suitable gloves when handling chemicals. Inspect all gloves for
defects before usage.

31. Know the location of
emergency equipment.
Be aware of the hazards posed
by the work of others in the
laboratory.
Make others in the laboratory
aware of any specific hazards
associated with your work.

32. Laboratory equipment must be regularly inspected and serviced
as per manufacturer’s recommendations

33. When heating a test tube or other apparatus, never point it towards
yourself or others.
Be sure that glassware has cooled before touching it.
Dilute concentrated acids and bases by slowly pouring the acid or
base into the water while stirring.
Keep work area clean and uncluttered. Maintaining good
housekeeping helps to prevent accidents.
Store coats, bags and other personal items in a designated area, not
on bench tops.
Keep drawers and cabinets closed when not in use.
Never heat flammable substances with an open flame. Use a water
bath.

34. Thank you