2. Why is it a Hazard ?
It is a Hazard because it by
itself or by interacting with
other variables can result in
Death, Injury, Property
damage and any other loss.
Safety Control Department
3. Classification of Electrical Hazards
Electrical Hazards
Secondary Hazard
( Involuntary Reflex
Action )
Electrical
Shock
Burns Fire &
Explosion
Static Electricity Spark
Dropping of
Tools
& Objets
Pearson
Falling
From
Height
Safety Coordination Department
Flash
Over Burn
Joules Burn
Primary Hazards
4. HEALTH HAZARD
WELDING OF STAINLESS STEEL AND ALUMINIUM MAY
GENERATE UNACCEPTABLE LEVELS OF OZONE
OZONE IS GENERATED BY THE EFFECT OF ULTRA VIOLET RADIATION
ON THE AIR IMMEDIATELY SURROUNDING THE GAS SHIELD
5.
6.
7.
8.
9. What is Electric Shock ?
Electric Shock is a sudden and
accidental stimulation of body’s
nervous system by electric
current.
Current will flow due to voltage
difference through a low
resistance i.e. the human body in
this case.
Safety Control Department
10. Severity of shock is not determined
by Voltage alone but….
depends on:
1. Quantity of current flowing through the body
2. The path of the current flowing through the
body.
3. The length of time, current flowing through the
body.
Safety Control Department
11. Effect of Current flowing through the body.
• 1 to 8 mA - Tingling sensations, Not painful
• 8 to 15 mA - Painful shock, Individual Can let go at
will as muscular control is not lost
• 15 to 20 mA - Painful shock, Muscular control of
adjacent muscles lost, cannot let go
• 20 to 50 mA - Severe muscular contraction, breathing
difficulty
• 50 to 200 mA - ( Possible) Ventricular fibrillation, a
heart condition that results in instant
death
• 200 - 500 mA - Severe burns, muscular contraction so
severe that chest muscles clamp down the
heart and stop it.
Note: Reaction will vary with frequency and time of exposure
12.
13. Human resistance to electric current
Dry skin resistance - 100,000 to 500,000 Ohms
Wet skin resistance - 1000 Ohms or Less
Internal body resistance - Hand to feet 400 Ohms
Ear to ear 100 Ohms
3 Times DC is equal to AC in effect.
Frequencies 20 to 100 Hz are very dangerous.
Danger Limit : 24 Volts AC for children
60 Volts AC for Adults
14. What is Flash Over?
-If an earthed conductor is brought close
to another conductor at a high voltage.
-The insulation of the air between them
may break down giving rise to a spark.
-This ionises the air considerably lowering
its resistance,
- Which in turn allows the current to
increase so that an electric arc is set-up.
Safety Control Department
15. What is Flash Burn ?
If the earthed conductor is human being ,
he will be burned by the arc rather than
directly coming in contact with the
conductor.
Since air resistance is lowered large
current flows and victim is subjected to
double event…
a) burn by arc
b) shock by passage of current
Safety Control Department
16. What is Joules burn ?
The passage of an electric current along-with
any conductor is accompanied by the dissipation
of heat according to Joules Law…
Heat Produced = I2 ×
R ×
t
where
I Current in Amps.
R Resistance in Ohms
t Time in seconds.
As the skin is the site of highest resistance in
the body it is here that burning is most likely
to occur .
Safety Control Department
17. Do you think electric shock
discriminates on Gender basis ?
Yes, it does so.
Provided all the physical conditions
are same, women get shock more
severe
than men
Safety Control Department
18. Other factors affecting the degree of
shock
- Frequency of the current
- Phase of the heart cycle at the time of
current.
- Physical and psychological
condition of the person
Safety Control Department
19. # Isolation
# Marking danger signs
# Routine insulation of common parts
e.g.( knobs, dials, handles, etc.)
# Rubber mats at places from where
electrical panels are to be operated.
# Use of (PPE) rubber gloves and
non- conductive shoes.
Safety Control Department
What are the shock Protection Methods ?
20. About a quarter of all
reportable electrical
accidents involve
portable electric
apparatus
Safety Control Department
21. 1) Use double insulated tools ( make sure the
casing is not broken )
2) Use properly earthed tools
3) Use good condition cable
4) Always use a plug top ( three pin plug )
5) Use tool at rated voltage
6) Routing of cables must be proper
7) Never mis-use a portable tool
8) Get the tool properly checked periodically
9) If possible use portable tool with low voltage
system
Safety Control Department
Ways of safely using portable electric tools
22.
23.
24. Work Permit System
Why Permit System needed ?
• Prior communication to all concerned about work,
associated hazards etc.
• Hazards involved and preventive steps to be taken
can easily be implemented
• Easy to handle the emergency preparedness
• Legal liability
• Effective control of work
• Helps in work planning
25. The “Fatal Five” Main Causes of
Lockout/Tagout Injuries
Failure to stop equipment
Failure to disconnect from power
source
Failure to dissipate (bleed,
neutralize) residual energy
Accidental restarting of
equipment
Failure to clear work areas
before restarting
26. Hazardous Energy Sources
Found in the Workplace
Electrical
Generated
Static
Mechanical
Transitional
Rotational
Thermal
Machines or
Equipment
Chemical
Reactions
Potential
Pressure
Hydraulic
Pneumatic
Vacuum
Springs
Gravity
27. Types of Lockout Devices
Plug Locks
Ball Valve
Lockout
Gate Valve
Lockout
Group
Lockout
Electrical
Hydraulic,
pneumatic, and
other
pressurized
systems
28. Lockout Procedure
Alert the operator (s) that power is being disconnected.
Preparation for Shutdown
Equipment Shutdown
Equipment Isolation
Application of Lockout Devices
Control of Stored Energy
Equipment Isolation-Verification
29. Removal of Lockout
Ensure equipment is safe to
operate
Safeguard all employees
Remove lockout/tagout devices.
Except in emergencies, each
device must be removed by the
person who put it on.
Last person to take off lock
Follow checklist
30. Special Situations
Servicing lasts
longer than one
shift.
Contractors are
performing
service or
maintenance at
your workplace
Worker who
applied lock is
not available
31. Remember
Never attempt lockout/tagout procedures
unless you have been trained and certified
by your employer
Never loan or share your lock,
combination, or key with anybody else.
Always be sure all lockout/tagout devices
are compatible with the environment in
which they will be used i.e. corrosive,
humid, etc.
32.
33.
34.
35.
36. Can earthing fail ?
Yes, earthing can fail due to
following reasons :
* Loose contacts in earthing
electrode.
* Earthing pit not maintained
properly.
* Continuity broken in earthing plate.
Safety Control Department
37. What should be done to maintain
proper earthing ?
The following points should be taken care
of:
- All contacts in earthing wiring should
be tight
- Resistance of earthing pit should be
checked regularly
- Continuity should be checked regularly
Safety Control Department
38. Safety Control Department
Static electricity is:
- The electrical charging of materials
- Through physical contact and separation
- The effects that result from the positive and
negative electrical charges formed by various
process.
- Transfer of electrons between bodies
When an electrical charge is present on the surface of
a non conducting body, where it is trapped or
prevented from escaping, it is called static electricity
Static
Electricity
39. Safety Control Department
(a) Pulverized materials passing through
chutes or pneumatic conveyors
(b) Steam, air, or gas flowing from any
opening in a pipe or hose, when the
steam is wet or the air or gas stream
contains particulate matter
(c) Nonconductive power or conveyor belts
in motion
(d) Moving vehicles
Common sources of Static
Electricity
Cont...
40. Safety Control Department
(e) Nonconductive liquids flowing through pipes
or splashing, pouring, or falling
(f) Movement of clothing layers against each
other or contact of footwear with floors
and floor coverings while walking
(g) Thunderstorms that produce violent air
currents and temperature differences that
move water, dust, and ice crystals creating
lightning
(h) Motions of all sorts that involve changes in
relative position of contacting surfaces,
usually of dissimilar liquids or solids
Common sources of Static Electricity
41. Safety Control Department
- The discharge of static electricity can cause
shock or a fire or explosion.
- Electrical charges may not in itself be a
potential fire or explosion hazard.
- For there to be an ignition there must be a
discharge or sudden recombination of the
separated positive and negative charges in
the form of an electric arc in an ignitable
atmosphere.
Static electricity Hazards