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Transcript
Safety Concepts and Practices
By: Laura Glantzberg
Georgia CTAE Resource Network
Some slides courtesy of Occupational Safety and Health Administration
(www.osha.gov)
Part 1: General Safety
General Safety-Fall Protection
• In subpart M of section
1926, OSHA (Occupational
Safety and Health
Administration) outlines fall
protection.
Guardrail System
Safety Net System
Personal Fall Arrest
System
• It states that, “Each
employee on a
walking/working surface
(horizontal and vertical
surface) with an
unprotected side or edge
which is 6 feet or more
above a lower level shall be
protected from falling by the
use of guardrail systems,
safety net systems, or
personal fall arrest
systems.”
General Safety-Confined Spaces
• OSHA’s definition of a
confined space is a
space large enough
for an employee to
enter and perform
work in, but has
limited
entrances/exits and is
not designed for
continuous
occupation by
employees
Confined Spaces Regulations
• Permits are required for workers to work in
confined spaces
• The space must be designated with a Warning
or Danger-Confined Space sign
• Proper ventilation is required
• More regulations for confined spaces are
outlined in OSHA’s 1910.146
Electricity - The Dangers
• About 5 workers are
electrocuted every
week
• Causes 12% of young
worker workplace
deaths
• Takes very little
electricity to cause
harm
• Significant risk of
causing fires
OSHA Office of Training & Education
Electrical Injuries
There are four main types of electrical
injuries:
• Direct:
Electrocution or death due to electrical
shock
Electrical shock
Burns
• Indirect
Falls
OSHA Office of Training & Education
Electrical Shock
• An electrical shock is received
when electrical current passes
through the body.
• One will get an electrical
shock if a part of the body
completes an electrical circuit
by…
– Coming in contact with both
wires of a circuit
– Coming in contact with one
hot wire and the ground
– Coming in contact with an
energized part while in
contact with the ground
OSHA Office of Training & Education
Severity of Shock
• Severity of the shock
depends on:
– Path of current through the
body
– Amount of current flowing
through the body (amps)
– Duration of the shocking
current through the body
• LOW VOLTAGE DOES
NOT MEAN LOW
HAZARD
– Low voltage is defined as
600 volts or less while High
Voltage is anything more
than 600 volts
OSHA Office of Training & Education
Electrical Shock Deaths
• There are around 700
deaths each year in
the United States that
are related to
electricity
• The main cause of
death from electrical
shock is fibrillation
– This is very rapid,
irregular contractions
of muscle fibers of the
heart
Defibrillator being used.
Burns
• Most common shockrelated injury
• Occurs when you
touch electrical wiring
or equipment that is
improperly used or
maintained
• Typically occurs on
hands
• Very serious injury that
needs immediate
attention
OSHA Office of Training & Education
Electrical Burns
• All electrical burns are
caused by heat
generated by the flow
of electricity
• Arc blasts are caused
by vaporizing metal
• If objects are thrown
during an arc blast, it
causes thermal
contact burns
Arc Blast between 2 nails
Part 2: Limiting Exposure to
Shock
Electrical Hazards and How to
Control Them
Electrical accidents
are caused by a
combination of three
factors:
– Unsafe equipment
and/or installation,
– Workplaces made
unsafe by the
environment, and
– Unsafe work practices.
OSHA Office of Training & Education
Hazard – Exposed Electrical Parts
Cover removed from wiring or breaker box
OSHA Office of Training & Education
Control – Isolate Electrical Parts
* Use guards or
barriers
- Section 2 requires
live parts be guarded
when they are
exposed for servicing
or repair
* Replace covers
Guard live parts of electric
equipment operating at 50
volts or more against
accidental contact
OSHA Office of Training & Education
Control – Isolate Electrical Parts Cabinets, Boxes & Fittings
Conductors going into them must be protected, and
unused openings must be closed
OSHA Office of Training & Education
Control – Close Openings
• Junction boxes,
pull boxes and
fittings must have
approved covers
• Unused openings
in cabinets, boxes
and fittings must be
closed (no missing
knockouts)
Photo shows violations
of these two requirements
OSHA Office of Training & Education
Hazard - Overhead Power
Lines
Control - Overhead Power
Lines
• Usually not insulated
* Examples of equipment that can contact
power lines:
– Crane
– Ladder
– Scaffold
– Backhoe
– Scissors lift
– Raised dump truck bed
– Aluminum paint roller
•
•
•
•
•
Stay at least 10 feet away
Post warning signs
Assume that lines are energized
Use wood or fiberglass ladders,
not metal
Power line workers need special
training & PPE
Hazard - Inadequate Wiring
Wire Gauge
WIRE
Wire gauge measures wires ranging in size
from number 36 to 0 American wire gauge
(AWG).
• Hazard - wire too small for the
current
• Example - portable tool with
an extension cord that has a
wire too small for the tool
– The tool will draw more
current than the cord can
handle, causing
overheating and a possible
fire without tripping the
circuit breaker
– The circuit breaker could
be the right size for the
circuit but not for the
smaller-wire extension cord
OSHA Office of Training & Education
Control – Use the Correct
Wire
Must be 3-wire type and designed for hard or extra-hard use
• Wire used depends on operation, building
materials, electrical load, and
environmental factors
• Use fixed cords rather than flexible cords
• Use the correct extension cord
OSHA Office of Training & Education
Hazard – Defective Cords & Wires
* Cords can be damaged by:
- Aging
- Door or window edges
- Staples or fastenings
- Abrasion from adjacent materials
- Activity in the area
* Improper use can cause shocks, burns or fire
* Plastic or rubber covering is missing
* Damaged extension cords & tools
OSHA Office of Training & Education
Control – Cords & Wires
* Insulate live wires
* Check before use
* Use only cords that are 3-wire type
* Use only cords marked for hard or
extra-hard usage
* Use only cords, connection
devices, and fittings equipped with
strain relief
* Remove cords by pulling on the
plugs, not the cords
* Cords not marked for hard or extrahard use, or which have been
modified, must be taken out of
service immediately
OSHA Office of Training & Education
Personal Safety Precautions
• Always know the voltage rating of the
equipment you are working with.
• If equipment is in the 300-750 volt rang,
stay at least a foot away from the
energized equipment.
OSHA Office of Training & Education
Personal Protective Equipment
(PPE)
• Includes:
– Gloves
– Eye Protection
– Insulating
Blankets
– Certain Types of
Clothing
Eye Protection
OSHA Office of Training & Education
When Must Eye Protection be
Provided?
*According to article CFR 1910.335 section 1, it is required to
“wear protective equipment for the eyes or face wherever
there is danger of injury to the eyes or face from electric arcs
or flashes or from flying objects resulting from electrical
explosion.”
* Especially when any of these hazards are present:
• Dust and other flying particles, such as metal shavings or
sawdust
• Corrosive gases, vapors, and liquids
• Molten metal that may splash
• Potentially infectious materials such as blood or hazardous
liquid chemicals that may splash
• Intense light from welding and lasers
Working Near Exposed Live Parts
• When working near exposed
live parts, OSHA requirements
state: “Protective shields,
protective barriers, or insulating
materials shall be used to protect
each employee from shock, burns,
or other electrically related injuries
while that employee is working near
exposed energized parts which
might be accidentally contacted or
where dangerous electric heating or
arcing might occur. When normally
enclosed live parts are exposed for
maintenance or repair, they shall be
guarded to protect unqualified
persons from contact with the live
parts.”
Rubber Gloves and Insulating
Blankets
• Rubber Gloves and blankets should be matched
to the voltage rating of the equipment or
electrical circuit.
– Class Zero rubber protective equipment is acceptable
for low voltage work.
• Any damage at all reduces the insulating ability.
– Type 1 rubber protective equipment can be damaged
by corona cutting and ultraviolet rays.
Gloves
• Wearing leather
protectors over rubber
gloves prevents
cuts/punctures.
• Clean gloves with
warm water. After
they have been
tested, store in a cool,
dry, dark place.
Testing Gloves
• Inspect gloves before
each use.
• An air test is
completed by trapping
air in a glove to check
for leaks.
– Do NOT use
compressed air, it
could damage the
glove.
What Should You Do…
• If there is ANY damage at all or the
protective equipment doesn’t pass
inspection, the equipment should be
DISCARDED!
The Award for Best Clothing Goes
To…
• COTTON!
– Why? Because
Cotton is less likely
to burn. Also, it is
best for non-static
clothes.
Protective Apparel
• Other types of
protective apparel
include: rubber
sleeves, fire suits
and face shields.
Face Shields
• Face Shields
should be worn
during switching
operations.
• Face shields do
not protect from
impact so safety
glasses or goggles
must also be worn
Part 3: Specialty Tools and
System De-Energizing
Insulating Blankets
• Insulating blankets
are used to protect
workers from
accidental contact
with a power-source.
• They are only used to
cover equipment.
Hot Sticks
• Hot Sticks are an
insulated tool used
for manually
disconnecting
switches.
• When storing hot
sticks, they should
hang vertically.
Fuse Pullers
• Fuse pullers make it
easier to install or
remove fuses
• They should be
made of nonconductive material
• Spread guards can
be used with fuse
pullers to prevent
them from spreading
during use
Capacitors
• Capacitors are
components that
store electricity even
when power is turned
off.
• When working with
equipment that has a
capacitor, discharge
the capacitor to
protect yourself
Shorting Probe
• Shorting probes are used to discharge
capacitors
• While working, shorting probes should
remain attached as an extra safety
precaution.
Working Around Energized Circuits
• To ensure safety, OSHA and NFPA
(National Fire Protection Association) both
have requirements for wearing safety
glasses when around energized circuits.
• NFPA 70-E requires that eye and face
protection are worn whenever there is a
danger of injury from electric arcs, flash, or
explosion.
How Do I Verify a Circuit is
De-Energized?
• ALWAYS
– 1. Ensure lockout tag-out
2. Verify test equipment
3. Check the circuit with test group
4. Verify test equipment again
Jewelry Reminder
• Never wear jewelry when working around
electricity because it is a good conductor
of electricity!
Always be Alert
• It is critical that you stay alert about
what is going on around you because
safety situations are constantly
changing.
Part 4: OSHA and Electricity
What is OSHA?
• OSHA stands for Occupational Safety and
Health Administration
• According to OSHA, employees have a
duty to follow the safety rules and
regulations of their employer
• It is important to follow safety rules and
regulations not only to be free of
accidents, but also because if you don’t it
could reduce your benefits or cost you
your job.
1910 vs. 1926
• OSHA has two sets of regulations dealing
with the construction industry: 1910 and 1926
• The standards set forth in 1926 take
precedence over 1910 unless more stringent
standards exist in 1910.
Important OSHA Standards
• Section 1910.302 through1910.308
contain design safety regulations for all
electrical equipment and installations used
to provide workplace power and lighting
• Section 402 only applies to the scope of
the standard
• Section 403 covers equipment installation
clearances, identification and examination
OSHA Standards (cont.)
• Section 404 discusses grounded, outside
and service conductors, grounding
requirements, and over-current protection
• Section 405 addresses wiring methods,
components and equipment for general
use
• Section 406 covers special purpose
equipment and installations
More OSHA Standards
• Section 407 covers hazardous locations that
contain (a) flammable gases or materials (b)
there is a combustible concentration present
• Section 408 covers special systems not
covered in other articles
• Section 1926.416 is special because it
provides an overview
Even More OSHA Standards
• 1910.332 applies to training requirements
for employees who face the risk of
electrical shock
• Section 416-417 covers safety practices
necessary to prevent electric shock and
related injuries
• Section 431 was added to reinforce
regulations covering portable electrical
equipment, electrical test equipment and
load break switches
The List Goes On…
• Section 416 covers Personal Protective
Equipment (PPE) requirements for
persons in vicinity of electrical hazards
• Section 1926 Subpart K addresses safety
requirements necessary for electrical
safety in the construction industry
The Standards Say…
• If you work on electrical equipment, the
work should be done with circuits deenergized and cleared/grounded
• All conductors, buses, and connections
should be considered energized (or hot)
until proven otherwise
• Breakers must be locked out and tagged
• Before replacing a fuse, remove power
from the circuit.
Part 5: Assured Grounding
and Lockout/Tag-Out
Electrical Codes
• All electrical
work shall be in
compliance with:
– OSHA
– National
Electrical Code
(NEC)
Power Tools
• Grounded tools must have 3rd grounding
wire
• Double insulated tools have all electrical
components isolated from the operator and
require no external grounding
Extension Cords
• Only 3 wire extension cords are allowed for use
on construction sites
• Never run an extension cord through a doorway
or window
• Ground Fault Circuit Interrupters (GFCIs) must
be used if you’re using an extension cord with a
permanent receptacle
• Flexible cords must be continuous. This means
there can be no splices
Basics of Lockouts and Tag-Outs
• The purpose of the OSHA
lockout/tag-out rule is to
ensure equipment is
isolated from all potentially
hazardous energy and
tagged before any servicing
or work
• The lockout/tag-out
procedure does not apply to
troubleshooting procedures
when the equipment must
be on to perform the
procedures
The Basics Continued
• You must notify all affected employees
– An affected employee is anyone working on or near
equipment that has been locked/tagged-out
• Training is to include recognition of hazardous
energy sources, types and magnitude of energy
sources, and the procedure for energy isolation
and control
• Danger tags must be used in conjunction with
locks
Lockout/Tag-Out Steps
1. Notify all affected and
authorized personnel
2. Shut down the
equipment or system
3. Lockout the energy
source and test
disconnects to be sure
they can’t be turned on
4. Lockout and tag-out the
required switching
5. Attach equipment or
system to the ground
6. Verify the test
equipment is
functioning properly
7. Confirm all switches
are open and verify the
equipment/system is
de-energized using
proper test equipment
8. Retest equipment or
system if you have to
leave even for a short
period
Reminders
• Avoid wearing loose fitting or torn clothing
• Before beginning any work, you should test the
voltage
• You should ALWAYS use appropriate test
equipment to check for power
• You must also notify all affected employees that
the lockout/tag-out has ended and power is being
restored