Transcript electrical fires

Electrical hazards are present in all laboratories. Adherence to all
electrical safety standards is essential in preventing electrical
accidents
A COMPLETE CIRCUIT OR LOOP IS NECESSARY
FOR CURRENT TO FLOW
ELECTRICITY IN THE BODY

Muscles

Muscles control all the body movements

Including & importantly those that keep us alive - Breathing and Heart

The brain controls voluntary muscles using Current pulses along
nerves
ELECTRICITY IN THE BODY
External
current through the body causes

Loss of muscle control

Spasms & Involuntary movement
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Inability to let go

Burns - external & internal
The severity and effects of an electrical
shock depend on a number of factors,
such as

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The pathway through the body
The amount of current
The length of time of the exposure
Whether the skin is wet or dry.
PHYSIOLOGICAL EFFECTS OF ELECTRICITY
Current
Reaction
1-5 Milliampere
Slight shock felt; not painful but
disturbing
6-30 Milliamperes
Painful shock; "let-go" range
50-150
Milliampere
1,000-4,300
Milliamperes
10,000+
Milliamperes
Extreme pain, respiratory arrest,
severe muscular contraction
Ventricular fibrillation
Cardiac arrest, severe burns, and
probable death
ELECTRICAL HAZARDS
Major hazards associated with electricity are electrical shock and fire.
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Electrical shock occurs when the body becomes part of the electric
circuit , when:
An individual comes in contact with both wires of an electrical
circuit.
One wire of an energized circuit and the ground.
Or a metallic part that has become energized by contact with an
electrical conductor.
 In
addition to the electrical shock hazards,
sparks from electrical equipment can serve as an
ignition source for flammable or explosive
vapors.
Loss of electrical power can result in extremely
hazardous situations:
 Flammable or toxic vapors may be released as a
chemical warms when a refrigerator or freezer
fails.
 Fume hoods may cease to operate, allowing
vapors to be released into the laboratory.
COMMON ELECTRICAL PROBLEMS
Extension Cords and Power Strips
 Power Cords
 Solvents and Electricity
 Water and Electricity
 Laboratory Equipment
 Capacitors and Transformers

POWER STRIPS ARE APPROVED FOR USE ONLY WITH COMPUTERS AND
COMPUTERIZED EQUIPMENT. POWER STRIPS SHOULD BE USED
SPARINGLY. CARE MUST BE TAKEN NOT TO OVERLOAD POWER STRIPS.
EXTENSION CORDS ARE APPROVED FOR TEMPORARY USE ONLY. IF
EXTENDED USE IS REQUIRED, HARD WIRING SUCH AS A NEW OUTLET
SHOULD BE INSTALLED. EXTENSION CORDS ARE EASILY FRAYED, A
CONDITION WHICH MAY EXPOSE BARE WIRES.
Power cords are doubly insulated and should be replaced if the outer
layer of insulation becomes frayed exposing wires.
POWER CORDS
Avoid dangling cords
and cords at floor.
OVERLOADS OCCUR WHEN MORE CURRENT FLOWS THROUGH A CORD
THAN IT IS RATED TO HANDLE. POWER STRIPS CAN BE OVERLOADED IF
TOO MANY HIGH CURRENT DRAW DEVICES ARE PLUGGED IN AT ONE TIME
COMMON LABORATORY EQUIPMENT SUCH AS CENTRIFUGES AND
OVENS ARE HIGH CURRENT DRAW DEVICES. IF TWO OR MORE HIGH
CURRENT DRAW DEVICES ARE PLUGGED INTO THE SAME OUTLET OR
POWER STRIP AN OVERLOADED CIRCUIT MAY RESULT.
CARE MUST BE TAKEN TO INSURE THAT POWER CORDS DO NOT
COME IN CONTACT WITH HOT SURFACES SUCH AS THE TOP OF A
HOT PLATE WHERE THEY MAY MELT EXPOSING BARE WIRES.
POWER STRIPS MUST BE LOCATED OUTSIDE OF ANY
FUME HOOD WHERE FLAMMABLE VAPORS ARE PRESENT.
WATER AND ELECTRICITY
Eyewashes should be
located away from
electrical devices and
outlets. Outlets within
six feet of a sink or other
source of plumbing must
be protected in order to
minimize shock hazards.
An unprotected outlet is
illustrated in this picture
Safety showers must not be
located directly over switches,
outlets, equipment, or other
sources of electrical energy
such as those shown in the
picture to the left.
POWER SUPPLIES REPRESENT A POTENTIALLY LETHAL SOURCE OF
ELECTRICAL ENERGY. EXPOSED CONNECTORS SUCH AS BANANA
CLIPS (ALLIGATOR CLIPS) SHOULD NEVER BE ATTACHED TO A
POWER SUPPLY OR ANY OTHER HIGH VOLTAGE, HIGH CURRENT
PRODUCING DEVICE.
Electrophoresis equipment
containing high voltage
power supplies are found in
many laboratories.
 Care must be taken to use
only approved equipment.
 Leads should be checked
periodically for frays.
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Flammable storage
refrigerators are specially
designed for flammable
liquid storage. The interior
of these types of
refrigerators do not contain
any potential spark sources
such as lights and switches.
BASIC ELECTRICAL SAFETY GUIDELINES
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Learn the location of your electrical panels and shut-off switches
so you can quickly disconnect power in the event of an
emergency. Always leave at least a 3-foot clearance around
electrical panels for ready access.
Plan ahead for what steps will be taken in the event of a power
loss.
Conduct a periodic inspection of laboratory electrical equipment
to be sure it is in good condition.
Electrical outlets should have a grounding connection and accept
three-prong plugs. Multiple plug outlet adapters are not allowed.
ELECTRICAL FIRES
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Unplug equipment first.
Use dry chemical fire
extinguisher.
If fire is large, unplug
equipment and call fire
dept.
Never use water!!

Type A fire extinguishers use water to
put out fires. They are not approved
for use on electrical fires. Type A
extinguishers are denoted by a
pressure gauge at the top of the unit
that indicates whether or not the
extinguisher is fully charged