Transcript Laboratory Electricity Safety

Learning Objectives
• Identification of electrical
hazards in laboratories.
• Applying safe work
practices to minimize risks.
Basic Laboratory Electrical Hazards
• Two main areas of concern
– Electrical shock or burns
– Fires and explosions
Electric Shock Injuries
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Severe burns
Indirect accidents
Cardiac arrest
Damage to muscles,
the heart or other
internal organs, or the
brain
Factors Impacting Electrical Shock
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Moisture
Type and/or amount of voltage
Grounding
Path of current through body
Area of body contact
Pressure & duration of contact
Physical size/condition/age of person
Personal protective equipment used
Factors Impacting Electrical Shock
Shock Hazards
• Improper use of
electrical equipment.
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extension cords
multi-plug strips
ungrounded equipment
operating equipment
without safety guards
Shock Hazards
• Damaged electrical
equipment could be a shock
hazard.
– extension cords
– power cords
– electrophoresis unit
• Always inspect electrical
equipment for damage
before use.
• Do not use damaged
equipment.
Shock Hazards
• Replace flexible cords-QEW
Shock Hazards
• Condensation and Spills
– May cause equipment to overheat,
smoke, or catch fire.
– Risk of electric shock.
– Condensation is more likely on
equipment located in cold rooms.
• Precautions
– Locate electrical equipment to minimize
the possibility of spills.
– If liquids are spilled onto electrical
equipment, shut off the power
immediately at the circuit breaker and
unplug the apparatus.
Shock Hazards
• Repairing Electrical Equipment
– Only “qualified persons” should perform
repairs on electrical equipment.
– Qualified Person “A person familiar with
the construction and operation of the
equipment and the hazards involved.” 29
CFR 1910.399
• Safety Precautions for Qualified Persons
– Turn off and unplug equipment before
attempting repairs.
– Energized components may exist within a
device even if it is turned-off and
disconnected from its power source.
– Use appropriate PPE.
Laboratory Accident:
Worker shocked by electrophoresis unit
• A laboratory worker received a potentially fatal
electrical shock when he accidentally touched an
exposed high voltage electrical connector on an
electrophoresis device. The contact points were on
the right elbow and right knee. Had one of the
contacts been on the opposite side of the body, the
shock could have been fatal.
Laboratory Accident:
Worker shocked by electrophoresis unit
• What could be done to prevent this from
happening again?
– Fix the machine so there are no more exposed
conductors.
– Perform regular safety inspections on the
electrophoresis unit to identify hazards.
– Train employees to use the machine safely.
Laboratory Accident:
Worker Shocked by Laser Power Supply
• A laboratory worker noticed condensation on the high voltage
power supply for a high powered laser. The worker decided he
would wipe the moisture with a tissue. The interlocks had been
defeated and guard removed from the power supply. With the
power on, the worker wiped the moisture with a tissue making
contact with an exposed anode terminal at approximately
17,000 volts DC to ground.
• He received a severe electrical shock and second degree burns
to his right thumb and abdomen. He had no pulse and was not
breathing. Public Safety officers were nearby and immediately
started CPR. The ambulance crew arrived and was able to
restore his heartbeat using a defibrillator.
Laboratory Accident:
Worker Shocked by Laser Power Supply
• How could the laboratory worker have
avoided this near-fatal accident?
– The interlocks should not have been defeated.
– The guard should not have been removed.
– Shut off power to laser before cleaning or
performing maintenance to avoid working
around energized exposed conductors.
Electrical Ignition Sources
• The Fire Triangle
– Fuel
– Heat (spark)
– Oxygen
• If one of the three
components of the fire
triangle is not present
you will not have a
fire.
Electrical Ignition Sources
• Electrical devices can
serve as ignition sources
in the presence of
flammable vapors.
• Flammable vapors must
be isolated from all
potential ignition sources.
Isolating Ignition Sources
• Follow flammable liquid storage guidelines
to prevent the release of vapors.
• Work with flammable liquids in fume hoods
or areas isolated from electrical devices.
• Avoiding using flammable liquids where a
spill could reach an ignition source.
• Do not use spark creating electrical
equipment with flammable liquids.
Electrical Ignition Sources
• What electrical devices are unsafe to use
around flammable liquids?
• Electrical equipment may have induction
motors or series-wound motors.
– Series-wound motors produce sparks.
– Induction motors do not create sparks.
Electrical Ignition Sources
• Non-Laboratory designed
equipment with series-wound
motors.
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Blenders
Power drills
Mixers
Vacuums
• Do not use around
flammable liquids.
Electrical Ignition Sources
• Laboratory equipment that may
have series-wound motors.
– Stirring and mixing devices
– Hot plates
– Heat guns
– Refrigerators and freezers
• Is your equipment explosion
proof?
• If equipment is not explosion
proof do not use around
flammable liquids.
Summary
Laboratory Electrical Safety
• Equipment Inspections.
• Where are your circuit breakers?
• Minimizing condensation and
spills.
• Repairing electrical equipment
• Working with flammable vapors.
• Ignition Sources