This document provides an overview of arc flash hazards and safety. It discusses what an arc flash is, common injuries caused, and important temperature thresholds. The document reviews revisions to NFPA 70E standards regarding arc flash safety. It explains key terms like flash protection boundaries and limits of approach. The document outlines procedures for performing arc flash calculations and determining appropriate personal protective equipment.
Practical Electrical Substation Safety for Engineers and TechniciansLiving Online
Electrical substation safety is an important issue in utility networks as well as large industrial installations and requires adequate attention in the stages of system planning, design, installation, operation and maintenance. A number of serious accidents including fatalities occur every year in industrial establishments due to accidents involving electricity, resulting in huge financial losses and wasted man-hours. Electrical safety is a well-legislated subject and the various Acts and Regulations lay a lot of stress on the responsibility of both employers and employees in ensuring safe working conditions.
In this workshop, we will take a look at the theoretical aspects of safety as well as the practical and statutory issues. Safety is not simply a matter of taking precautions in the workplace. It has to start at the stage of equipment design. Safety should be built into the design of electrical equipment and it is the responsibility of every manufacturer of electrical equipment to remove every possible hazard that can arise from its normal use. Correct selection and application of electrical machinery is also important for ensuring safety. A thorough inspection during initial erection and commissioning as well as on a periodic basis thereafter is also very essential to ensure safety. Batteries used in substations need particular attention since they contain toxic materials such as lead, corrosive chemicals such as acid or alkali.
Electrical safety is not just a technical issue. Accidents can only be prevented if appropriate safety procedures are evolved and enforced. This includes appropriate knowledge of equipment and systems imparted through systematic training to each and every person who operates or maintains the equipment. We will cover all these aspects in detail.
MORE INFORMATION: http://www.idc-online.com/content/practical-electrical-substation-safety-engineers-and-technicians-28
Arc flash incidents can be costly in terms of personnel injury and equipment repair/replacement. This presentation provides an overview of the NFPA 70E 2012 Standard for Electrical Safety in the Workplace and the requirements of the standards, which are intended to better protect electrical workers from injury when they work on energized electrical equipment. This includes all aspects of facility and employer responsibilities for compliance to the NFPA 70E standards, as well as the current status of OSHA enforcement of these standards. Copyright AIST Reprinted with Permission.
How to work safely while working with electricity or electrical equipment. what are the safety rules to be followed? what is the safe system of work while working on electrical equipment. what kind of safety components to be used in place?
Regards, Mr. SYED HAIDER ABBAS
MOB. +92-300-2893683 MBA in progress,NEBOSH IGC, IOSH, HSRLI, NBCS,GI,FST,FOHSW,ISO 9001, 14001,
'BS OHSAS 18001, SAI 8000, Qualified .
Practical Electrical Substation Safety for Engineers and TechniciansLiving Online
Electrical substation safety is an important issue in utility networks as well as large industrial installations and requires adequate attention in the stages of system planning, design, installation, operation and maintenance. A number of serious accidents including fatalities occur every year in industrial establishments due to accidents involving electricity, resulting in huge financial losses and wasted man-hours. Electrical safety is a well-legislated subject and the various Acts and Regulations lay a lot of stress on the responsibility of both employers and employees in ensuring safe working conditions.
In this workshop, we will take a look at the theoretical aspects of safety as well as the practical and statutory issues. Safety is not simply a matter of taking precautions in the workplace. It has to start at the stage of equipment design. Safety should be built into the design of electrical equipment and it is the responsibility of every manufacturer of electrical equipment to remove every possible hazard that can arise from its normal use. Correct selection and application of electrical machinery is also important for ensuring safety. A thorough inspection during initial erection and commissioning as well as on a periodic basis thereafter is also very essential to ensure safety. Batteries used in substations need particular attention since they contain toxic materials such as lead, corrosive chemicals such as acid or alkali.
Electrical safety is not just a technical issue. Accidents can only be prevented if appropriate safety procedures are evolved and enforced. This includes appropriate knowledge of equipment and systems imparted through systematic training to each and every person who operates or maintains the equipment. We will cover all these aspects in detail.
MORE INFORMATION: http://www.idc-online.com/content/practical-electrical-substation-safety-engineers-and-technicians-28
Arc flash incidents can be costly in terms of personnel injury and equipment repair/replacement. This presentation provides an overview of the NFPA 70E 2012 Standard for Electrical Safety in the Workplace and the requirements of the standards, which are intended to better protect electrical workers from injury when they work on energized electrical equipment. This includes all aspects of facility and employer responsibilities for compliance to the NFPA 70E standards, as well as the current status of OSHA enforcement of these standards. Copyright AIST Reprinted with Permission.
How to work safely while working with electricity or electrical equipment. what are the safety rules to be followed? what is the safe system of work while working on electrical equipment. what kind of safety components to be used in place?
Regards, Mr. SYED HAIDER ABBAS
MOB. +92-300-2893683 MBA in progress,NEBOSH IGC, IOSH, HSRLI, NBCS,GI,FST,FOHSW,ISO 9001, 14001,
'BS OHSAS 18001, SAI 8000, Qualified .
Electrical Commissioning and Arc-Flash Safety presentationMichael Luffred
Electrical Commissioning and Arc Flash Safety training presentation given November 21, 2013. Mike Luffred presented this information as a technical seminar for the National Capital Chapter region (PA/NJ/DE/VA/MD/DC) of the Building Commissioning Association. The presentation was given at the Eaton Experience Center in Warrendale, PA to help commissioning engineers understand the importance of arc flash safety in the industry.
The electrical arc creates a pressure wave. The incident energy is the energy of this arc-flash coming into contact with a surface. Essentially an electric arc creates a radiation burn which accounts for the internal burns a person can receive when exposed to an electrical arc flash.
The presentation is based on the discussions about the safety in Power Plants and substations. The presentation is a part of the seminar on Electrical safety and reliability. The reporting of accidents was also discussed at length in the seminar
Practical HV and LV Switching Operations and Safety RulesLiving Online
In this workshop, we will take a look at the theoretical aspects of safety as well as the practical and statutory issues. One of the main causes of electrical accidents is said to be incorrect isolation of the circuits where work is to be done. To ensure safety of operators and maintenance personnel, proper switching procedures are necessary and more so when the circuits have multiple feeds and are complex. The possibility of voltage being fed back from secondary circuits needs to be considered as well. This workshop emphasises on the isolation procedures to ensure proper and safe isolation of HV, LV and secondary circuits.
Electrical safety is not just a technical issue. Accidents can only be prevented if appropriate safety procedures are evolved and enforced. This includes appropriate knowledge of equipment and systems imparted through systematic training to each and every person who operates or maintains the equipment. We will cover all these aspects in detail.
MORE INFORMATION: http://www.idc-online.com/content/practical-hv-and-lv-switching-operations-and-safety-rules-25
Be familiar with the fundamental concepts of electricity.
Be familiar with the effects of electricity on the human body.
Be able to recognize common electrical hazards.
This training presentation covers the basic on arc flash and other electrical hazards, including the effects of an arc flash incident and how to determine shock and flash protection boundaries for a safe workplace
Electrical Commissioning and Arc-Flash Safety presentationMichael Luffred
Electrical Commissioning and Arc Flash Safety training presentation given November 21, 2013. Mike Luffred presented this information as a technical seminar for the National Capital Chapter region (PA/NJ/DE/VA/MD/DC) of the Building Commissioning Association. The presentation was given at the Eaton Experience Center in Warrendale, PA to help commissioning engineers understand the importance of arc flash safety in the industry.
The electrical arc creates a pressure wave. The incident energy is the energy of this arc-flash coming into contact with a surface. Essentially an electric arc creates a radiation burn which accounts for the internal burns a person can receive when exposed to an electrical arc flash.
The presentation is based on the discussions about the safety in Power Plants and substations. The presentation is a part of the seminar on Electrical safety and reliability. The reporting of accidents was also discussed at length in the seminar
Practical HV and LV Switching Operations and Safety RulesLiving Online
In this workshop, we will take a look at the theoretical aspects of safety as well as the practical and statutory issues. One of the main causes of electrical accidents is said to be incorrect isolation of the circuits where work is to be done. To ensure safety of operators and maintenance personnel, proper switching procedures are necessary and more so when the circuits have multiple feeds and are complex. The possibility of voltage being fed back from secondary circuits needs to be considered as well. This workshop emphasises on the isolation procedures to ensure proper and safe isolation of HV, LV and secondary circuits.
Electrical safety is not just a technical issue. Accidents can only be prevented if appropriate safety procedures are evolved and enforced. This includes appropriate knowledge of equipment and systems imparted through systematic training to each and every person who operates or maintains the equipment. We will cover all these aspects in detail.
MORE INFORMATION: http://www.idc-online.com/content/practical-hv-and-lv-switching-operations-and-safety-rules-25
Be familiar with the fundamental concepts of electricity.
Be familiar with the effects of electricity on the human body.
Be able to recognize common electrical hazards.
This training presentation covers the basic on arc flash and other electrical hazards, including the effects of an arc flash incident and how to determine shock and flash protection boundaries for a safe workplace
Many workers working on energised equipment are injured and/or killed each year. Several of these casualties are a result of arc flash.
Arc Flash is considered as one of the most destructive and dangerous instances when dealing with electrical wirings. A single occurrence can destroy metals and it has the ability to kill a person if not protected by Arc Flash Clothing. An arc flash can create an arc blast that can shatter anything because it is as hot as the as surface of the sun. This kind of heat can destroy metals instantly and completely burn a body beyond recognition.
Arc Flash ProtectionSerious injuries are caused by the arc flash:
Burns
Respiratory system damage
Hearing damage
Skin penetration from flying debris
Eye and face injuries
An arc flash may happen instantly and if the worker does not have the correct protection, they will already be dead when the arc flash hits them.
The use of Arc Flash Protective Equipment will lessen the damages caused by an arc flash because all of these equipments are solely made to withstand the heat.
Typical Arc Flash Clothing Applications
Working on electrical systems and switchrooms at 500 volts, live testing and proving dead on electrical systems, fitting and removal of LV-HV earths on electrical systems, working on panels/control circuits with exposed energised conductors, removal of bolted covers from energised electrical equipment, racking in/out of switchgear, racking in/out of starters and control gear, live testing and proving dead on electrical systems 11-33kV - T&D UK stock a broad range of Arc Flash Clothing and PPE.
The technicians at Caddell Electric (http://dallaselectricrepair.com/) provide the best and most comprehensive commercial electrical services in the DFW Metroplex.
Five to 10 arc flash explosions occur in electric equipment every day in the United States. This number does not include cases in which the victim is sent to an ordinary hospital. Instead, these incidents are so severe the victims require treatment from a special burn center.
Few engineering or administrative controls are used to protect workers in India's coal mines. Workers are exposed to coal dust which contains respirable crystalline silica and heavy metals. Workers suffer from silicosis and other pulmonary diseases from their workplace exposures in the mines. There is no health insurance and workers have a limited life expectancy.
The Health Safety Executive (HSE) published information on occupational lung disease statistics in Great Britain in 2023. The results underscore exposure to occupational illness in various industries in the UK.
Individual work tasks and business operations vary from industry to industry as well as within each industry. OSHA has collected a wealth of industrial hygiene sample data prior to the change in collection methods. We looked at the OSHA data to determine where the risks occurred within each industry. The results were surprising and the level of effort to inform workers was limited at the same time. Since our investigation, the occupational exposure limits have also changed so we compared the past data sets to the new exposure limits. There were even more surprised in our analysis.
While some stress is good to help drive business excellence, too much stress can have the opposite effect. There are individual variabilities of performance based on experience, education, training, and other psychosocial issues. Understanding stress and how to cope is very important tool. We explore the concerns of workplace stress and stress withing interpersonal relationships.
Migrant children are being exploited as they enter into a new country in order to support their family. These children work in agriculture, construction, and maritime industries. Some are sold as slaves while others are held in bondage or contract labor. No controls are used to protect their health or wellbeing.
After the earthquake in Turkey, workers, public and private citizens were exposed to asbestos, respirable crystalline silica and heavy metals from the debris and cleanup operations. This slide deck helps to illustrate the health hazards created by this disaster. Controls should have been used to reduce the risk of exposure.
Workers, volunteers, and the public are exposed to respirable crystalline silica, asbestos, and heavy metals from both natural and manmade disasters. This presentation looks at the potential occupational health exposures and the controls that could be used to reduce risk.
Workplaces in China have few controls yet they display updated industrial operations showing the hierarchy of controls. In many industries, workers are exposed to very dusty operations from coal mining to construction. This presentation aims to highlight those operations and work tasks where improvements can be made. There are consultants and organizations that could provide support to reduce the risk of exposure and prevent occupational illness and disease.
Business and industry in Bangladesh are different from the remainder of the world. Occupational health and industrial hygiene are poorly represented in the country. Health hazards and risk of occupational illness and disease are prevalent. A hierarchy of controls should be developed by the government and rules of engagement enforced. Tax credits should be given to employers to improve their workplaces and business culture. Investments in human capital should be made to evaluate conditions and provide sustainable improvements to reduce the liability and risk of illness and promote prosperity.
The industrial hygiene profession is expanding far beyond protecting worker health. IHs are looking into climate change, environmental and public health concerns, sustainability, mental health and so much more.
Many questions have been raised regarding the protection of workers and the public during the pandemic. This presentation offers insight into the precautions necessary of preventing exposure and the controls needed to reduce risk.
Industrial hygiene is a science to protect workers from harm due to chemicals, biological and physical agents, radiological and ergonomic exposures. Our professions spans other concerns related to workplace health including drugs and alcohol, mental health and so much more.
What we see does not always relate to the occupational health and safety hazards in the workplace. While doing surveys, our brain only sees 10% of what's actually going on. Learn more how to be more aware of your surroundings.
The business world is changing and the need to keep workers and leaders informed is ever more important. However, the time constraints to deliver the message must be provided in short sound bites so that it can be managed with the myriad of other daily responsibilities. The answer is to provide training when workers and leaders can attend online. Lessons need to be short and deliver meaningful information. The lessons need to build upon each other so the entire message is complete at the end of the training. By reimaging how we can deliver information in a timely fashion will improve our capacity to protect workers, public and the environment in the future.
Occupational and environmental health and safety have taken center stage in all market segments across the globe. The cost benefit of protecting workers, public, and the environment outweighs the cost of negligence and avoidance by limiting liability and risk while improving human performance, productivity, profitability and prosperity.
Mental health and psychosocial disorders are pervasive throughout the business world. Leadership needs to understand the cost benefits of incorporating these issues into existing safety and health management systems to improve the livelihoods of bot workers and their families. By improving policy, programs and procedures, everyone benefits from a better working environment, climate and culture.
Heat stress is a concern for baseball and softball officials doing multiple games over a tournament weekend. Some officials can officiate 9-11 games over a three day period with little rest in between. With elevated air temperatures and relative humidity during mid-day, officials are affected by the environmental conditions. This affects not only their cognitive skills but their physical ability to call plays. Wearing the protective gear places an additional heat strain on the officials behind the plate. This presentation discusses these issues and offers a basic model to judge the relative risk of heat stress for officials and assigners who are in good physical condition.
Industrial hygienists and occupational health professionals have been evaluating work environments and providing solutions to business for decades. With the advancement in technology and expansion of the profession into neighboring disciplines, they can provide total work health to more vulnerable populations across the globe.
The SARS CoV-2 virus has had a different effect on construction as opposed to other industries. These essential workers find themselves in various indoor and outdoor environments either working alone or along side with multiple trades. So the exposures vary with job work tasks and locations. This brief examines when it is necessary to employ more engineering or administrative controls to protect worker health.
Whenever a business is going to make a capital improvement to protect workers from harm, a cost benefit analysis should be done to determine if it is a sound decision. There are several ways to make the determination, which is explored in this brief.
More from The Windsdor Consulting Group, Inc. (20)
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
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Ethnobotany and Ethnopharmacology:
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Introduction to Arc Flash/Blast Electrical Hazards
1. Introduction to Arc FlashIntroduction to Arc Flash
Compliance with OSHA, NFPA
70E and IEEE Standards
2. 22
Worker Training of Electrical Hazards Including
Arc Flash SH-16614-07
This material was produced under grant number
SH-16614-07 from the Occupational Safety and
Health Administration, U.S. Department of
Labor. It does not necessarily reflect the views
or policies of the U.S. Department of Labor, nor
does mention of trade names, commercial
products, or organizations imply endorsement by
the U.S. Government.
3. 33
OverviewOverview
• Introduction
• Revisions to the NFPA 70E
• Electrically Safe Work Conditions
• Energized Electrical Work Permit
• Flash Protection Boundary and Limits of
Approach
• NFPA 70E Boundaries and Spaces
• Flash Protection Calculations
• Choosing Correct PPE
• Reducing the Arc Flash Hazard
4. 44
IntroductionIntroduction
• What is Arc Flash?
– Arc flash results from an arcing fault, where
the electric arcs and resulting radiation and
shrapnel cause severe skin burns, hearing
damage, and eye injuries.
5. 55
IntroductionIntroduction
Why are we so interested in Arc Flash now?
– Numerous workers are injured and/or killed
each year while working on energized
equipment. Many of these casualties are a
result of arc flash.
– Working on energized equipment has become
commonplace in many industries.
6. 66
IntroductionIntroduction
Injuries that can result from an arc flash:
– Burns
– Respiratory system damage
– Hearing damage
– Skin penetration from flying debris
– Eye and face injuries
8. 88
IntroductionIntroduction
• A First Degree Burn is red and sensitive to
touch. There is minimal skin damage and
only the skin surface is involved.
Example: Sunburn
9. 99
IntroductionIntroduction
• A Second Degree Burn involves the first
and second layers of skin. The skin
reddens intensely and blisters develop.
Severe pain and swelling occur and
chance for infection is present.
10. 1010
IntroductionIntroduction
• A Third Degree Burn causes charring of
skin and coagulation of blood vessels just
below the skin surface. All three layers of
skin are affected. Extensive scarring
usually results.
11. 1111
IntroductionIntroduction
• Skin damage will occur based on the intensity of
the heat generated by an electrical arc accident.
The heat reaching the skin of the worker is
dependant on the following three factors:
– Power of the arc at the arc location
– Distance of the worker to the arc
– Time duration of the arc exposure
13. 1313
IntroductionIntroduction
Inhalation Injuries
In addition to burns, an arc flash can
cause inhalation injuries. More than a
hundred known toxic substances are
present in fire smoke. When inhalation
injuries are combined with external burns
the chance of death can increase
significantly.
14. 1414
IntroductionIntroduction
• The pressure of an arc blast is caused by
the expansion of the metal as it vaporizes
and the heating of the air by the arc
energy. This accounts for the expulsion of
molten metal up to 10 feet away.
• In addition, the sudden expansion of an arc
blast creates loud sounds that can cause
hearing damage.
15. 1515
Revisions To The NFPA 70ERevisions To The NFPA 70E
As a result of the injuries
and deaths related to arc
flash, changes/additions
have been incorporated
into the National Fire
Protection Association
publication number 70E,
the most recent version
being NFPA 70E-2004.
19. 1919
Arc Flash AwarenessArc Flash Awareness
• NIOSH DVD:
Arc Flash Awareness
– Information and
discussion about arc
flash and comments
from workers injured
by an arc flash
20. 2020
Electrically Safe Work ConditionsElectrically Safe Work Conditions
• The equipment is not and cannot be energized:
To ensure an electrically safe work condition:
– Identify all power sources,
– Interrupt the load and disconnect power,
– Visually verify that a disconnect has opened the circuit,
– Locking out and tagging the circuit,
– Test for absence of voltage, and
– Ground all power conductors, if necessary.
21. 2121
Electrically Safe Work ConditionsElectrically Safe Work Conditions
• Lockout/Tagout
– A single qualified person de-energizing one
set of conductors.
– An unqualified person may never perform a
lockout/tagout, work on energized equipment,
or enter high risk areas.
22. 2222
Energized Electrical Work PermitEnergized Electrical Work Permit
• When live parts over 50 volts are not
placed in an electrically safe work
condition it is considered energized
electrical work and must be down under a
written permit.
• Permit gives conditions and work practices
needed to protect employee from arc flash
or contact with live parts.
23. 2323
Energized Electrical Work PermitEnergized Electrical Work Permit
An Energized Electrical Work Permit will include:
– Circuit, equipment and location
– Why working while energized.
– Shock and arc flash hazard analysis
– Safe work practices
– Approach boundaries
– Required PPE and tools
– Access control
– Proof of job briefing
24. 2424
Flash Protection Boundary andFlash Protection Boundary and
Limits of ApproachLimits of Approach
• Definitions of Boundaries and Spaces
The closer you approach an exposed,
energized conductor or circuit part, the
greater the chance of an inadvertent
contact and the greater the injury that an
arc flash will cause. NFPA 70E-2004,
Annex C defines approach boundaries
and work spaces. The diagram on the next
slide illustrates these.
25. 2525
Flash Protection Boundary andFlash Protection Boundary and
Limits of ApproachLimits of Approach
Approach/Flash Protection Boundaries
26. 2626
Flash Protection Boundary andFlash Protection Boundary and
Limits of ApproachLimits of Approach
• Flash Protection Boundary
When an energized conductor is exposed,
you may not approach closer than the
flash boundary without wearing
appropriate personal protective clothing
and personal protective equipment.
27. 2727
Flash Protection Boundary andFlash Protection Boundary and
Limits of ApproachLimits of Approach
• Flash Protection Boundary
IEEE defines “Flash Protection Boundary”
as: An approach limit at a distance from
live parts operating at 50 V or more that
are un-insulated or exposed within which a
person could receive a second degree
burn.
28. 2828
Flash Protection Boundary andFlash Protection Boundary and
Limits of ApproachLimits of Approach
How Does Flash Protection Boundary Relate to
Working On Or Near Exposed Energized Parts?
• The radiant energy and molten material that is
released by an electric arc is capable of seriously
injuring or killing a human being at distances of up
to twenty feet.
The flash protection boundary is the closest
approach allowed by qualified or unqualified
persons without the use of arc flash PPE.
31. 3131
Flash Protection Boundary andFlash Protection Boundary and
Limits of ApproachLimits of Approach
Typical Detailed Label
32. 3232
NFPA 70E Boundaries and SpacesNFPA 70E Boundaries and Spaces
Good safety practices minimize risk:
• Switch remotely if possible.
• Standing aside and away as much as
possible during switching.
• Avoid leaning on or touching switchgear
and metallic surfaces.
• Use proper tools and PPE.
33. 3333
NFPA 70E Boundaries and SpacesNFPA 70E Boundaries and Spaces
• NFPA 70E, Section 130.3(B) states:
• If work will be performed within the flash
protection boundary, the flash hazard
analysis shall determine, and the
employer shall document, the incident
energy exposure of the worker in
(cal/cm2).
34. 3434
NFPA 70E Boundaries and SpacesNFPA 70E Boundaries and Spaces
NFPA 70E, Section 130.3 (B) states:
• The incident energy exposure
level shall be based on the
working distance of the worker’s
face and chest areas from a
prospective arc source for the
specific task to be performed.
35. 3535
NFPA 70E Boundaries and SpacesNFPA 70E Boundaries and Spaces
• NFPA 70E, Section 130.3(B) states:
Flame Resistant (FR) Clothing and Personal
Protective Equipment (PPE) shall be used by
the employee based upon the incident energy
exposure associated with the specific task.
36. 3636
Flash Protection CalculationsFlash Protection Calculations
• The Incident Energy and Flash Protection
Boundary can be calculated in an Arc
Flash Hazard Analysis.
• There are two methods:
– NFPA 70E-2004, Annex D
– IEEE Std 1584TM
37. 3737
Flash Protection CalculationsFlash Protection Calculations
Step 1
• Collect the System Installation Equipment
Data
Step 2
• Determine the Power System’s Modes of
Operation
– Normal operation, tie switched closed, dual
feeds
– Perform analysis for worst case condition
38. 3838
Flash Protection CalculationsFlash Protection Calculations
• Theoretically worst case fault magnitude
• Determines equipment interrupting ratings
• Impedance at fault location is considered
to be zero ohms
Step 3
• Determine the Bolted Fault Currents
– Find symmetrical RMS current and X/R ratio at each point of
concern.
39. 3939
Flash Protection CalculationsFlash Protection Calculations
Step 4
• Determine the Arc Fault Currents
– The arc fault current for each location where
an arc flash hazard exists and the portion of
the current that flows through the closest
upstream device that will clear this fault must
be determined
40. 4040
Flash Protection CalculationsFlash Protection Calculations
• Faults which are not bolted
• Poor electrical connection
between conductors can cause
arcing
• Arcing results in tremendous
heat (35,000)
Arcing Fault Current is fault current flowing through
an electrical arc plasma.
41. 4141
Flash Protection CalculationsFlash Protection Calculations
Step 5
• From the Protective Device Characteristics,
Find the Arcing Duration
– The total clearing time of the fault will
determine the “time” factor in the incident
energy equation.
42. 4242
Flash Protection CalculationsFlash Protection Calculations
The fault clearing time is
determined from the
Coordination Study’s
Time Current Curves.
The total clearing time of
the primary fuse for a
secondary side fault is 1
second.
TX Inrush
T4
T4
T4 Main Phase
T4 - T5 Phase
M2
T4
100 hp O/L
HMCP 250 A
MCC Fdr Phase
0.5 1 10 100 1K 10K
0.01
0.10
1
10
100
1000
CURRENT IN AMPERES
T4 arc flash.tcc Ref. Voltage: 480 Current Scale x10^2 T4 arc flash.drw
TIMEINSECONDS
1 sec
43. 4343
Flash Protection CalculationsFlash Protection Calculations
Step 6
• Record the System Voltages and
Equipment Classes
– For each bus or arc hazard location
Step 7
• Determine Working Distances
– Arc flash protection is always based on the
incident energy to a person’s face and body at
the working distance
44. 4444
Flash Protection CalculationsFlash Protection Calculations
Step 8
• Determine Incident Energy
– This is best done using a software package.
• Calculating incident energy requires the
following parameters:
– Max. bolted 3-ph fault current available at the
equipment
– Total protective upstream device clearing time max
fault current
– Distance of worker from the arc
45. 4545
Flash Protection CalculationsFlash Protection Calculations
Step 9
• Determine the Flash Protection Boundary
for All Equipment
– The incident energy for the flash-protection
boundary must be set at the minimum energy
beyond which a second degree burn could
occur - 1.2 cal/cm2
47. 4747
Flash Protection CalculationsFlash Protection Calculations
The estimated incident energy for an arc in
open air is:
EMA = 5271DA-1.9593 tA[0.0016F 2-0.0076F+0.8938]
EMA=maximum open arc incident energy (cal/cm2
)
DA=distance from arc electrodes (inches)
tA=arc duration (seconds)
F=bolted fault current in kA (16kA-50kA)
48. 4848
Flash Protection CalculationsFlash Protection Calculations
The estimated incident energy for an arc in
a box is:
EMB = 1038.7DB-1.4738 tA[0.0093F2-0.3453F+5.9675]
EMB=max 20 in. cubic box incident energy (cal/cm2
)
DB=distance from arc electrodes (inches) for 18 in.
and greater
tA=arc duration (seconds)
F=bolted fault current in kA (16kA-50kA)
49. 4949
Flash Protection CalculationsFlash Protection Calculations
• Test results have shown that the incident
energy for an open air arc is
approximately inversely proportional to the
distance squared.
• Enclosing a 3-ph arc in a box can increase
the incident energy from 1.5 to 3 times
depending upon the arc parameters and
box dimensions when compared to an
open air arc with the same parameters.
50. 5050
Flash Protection CalculationsFlash Protection Calculations
There are resources on the
internet to assist in calculations:
• http://www.littelfuse.com/arccalc/calc.ht
ml
• http://www.pnl.gov/contracts/esh-
procedures/forms/sp00e230.xls
• http://www.bussmann.com/arcflash/inde
x.aspx
52. 5252
Choosing Correct PPEChoosing Correct PPE
Section 130.7(A) states that employees
working in areas where there are electric
hazards shall be provided with, and shall
use, protective equipment that is designed
and constructed for the specific part of the
body to be protected and for the work to
be performed.
53. 5353
Choosing Correct PPEChoosing Correct PPE
• Personal Protective Equipment, PPE, for
the arc flash is the last line of defense.
• It is not intended to prevent all injuries, but
is intended to mitigate the impact of an arc
flash, should one occur.
54. 5454
Choosing Correct PPEChoosing Correct PPE
• After the Arc-Flash Hazard Analysis has
been performed, PPE is selected as
follows:
Clothing’s ATPV or EBT (in cal/cm2)
>
Calculated Hazard Level (in cal/cm2)
*ATPV can be obtained from clothing manufacturer
55. 5555
Choosing Correct PPEChoosing Correct PPE
ATPV - Arc Thermal Performance
Exposure Value
EBT - Breakopen Threshold Energy
Rating
Calculated Hazard Level - Incident
Energy in cal/cm2
59. 5959
Choosing Correct PPEChoosing Correct PPE
• Specialized Arc-Flash
Protection Equipment:
Face Shield -- Attaches to
Hard Hat
• Use: Hazard/Risk
Category 2
60. 6060
Choosing Correct PPEChoosing Correct PPE
• Specialized Arc-Flash
Protection Equipment:
Gloves and Leather
Protectors,
(ATPV Values not
Established for Rubber)
• Use: Hazard/Risk
Category 2, 3, and 4
for the Leather
Protectors
61. 6161
Choosing Correct PPEChoosing Correct PPE
• NFPA 70E, Section 130.7(C)(9)(a) states:
– When selected in lieu of the flash hazard
analysis of 130.3(A), Table 130.7(C)(9)(a)
shall be used to determine the hazard/risk
category for each task.
• NFPA 70E, Section 130.7(C)(10) states:
– Once the Hazard/Risk Category has been
identified, Table 130.7(C)(10) shall be used to
determine the required personal protective
equipment (PPE) for the task.
62. 6262
Choosing Correct PPEChoosing Correct PPE
The tables in NFPA 70E-2004 provide the
simplest methods for determining PPE
requirements. They provide instant
answers with almost no field data. The
tables provide limited application and are
conservative for most applications.
*These tables are not intended as a substitution for an arc hazard
analysis, but only as a guide.
67. 6767
Choosing Correct PPEChoosing Correct PPE
• NFPA 70E-2004, Section 130.7(C), Table
130.7(C)(9)(a) lists common work tasks
with respective Hazard/Risk category of
each task.
• After the Hazard Risk Category has been
determined from Table 130.7(C)(9)(a),
then Table 130.7(C)(10) is used to
determine the Protective Clothing and
Personal Protective Equipment required
for the task.
68. 6868
Choosing Correct PPEChoosing Correct PPE
Task (Assumes Equipment Is Energized, and Work Is Done
Within the Flash Protection Boundary)
Hazard/
Risk
Category
V-rated
Gloves
V-rated
Tools
CB or fused switch operation with enclosure doors closed 0 N N
Reading a panel meter while operating a meter switch 0 N N
CB or fused switch operation with enclosure doors open 1 N N
Work on energized parts, including voltage testing 2* Y Y
69. 6969
Choosing Correct PPEChoosing Correct PPE
• NFPA 70E, Table 130.7(C)(11) lists the
characteristics and degrees of protection
for various Flame Resistant (FR) clothing
systems.
70. 7070
Choosing Correct PPEChoosing Correct PPE
NFPA 70E Table 130.7(C)(11) Typical Protective Clothing Systems
Hazard
Risk
Category
Clothing Description (Number of
clothing layers is given in
parenthesis)
Total
Weight
Minimum Arc Thermal
Performance Exposure
Value (ATPV)* or
Breakdown Threshold
Energy (EBT)* Rating of
PPE
oz/yd
2
cal/cm
2
0 Untreated Cotton (1) 4.5 - 7 N/A
1 FR shirt and FR pants (1) 4.5 - 8 5
2
Cotton underwear plus FR shirt and
FR pants (2)
9 - 12 8
3
Cotton underwear plus FR shirt and
FR pants plus FR coverall (3)
16 - 20 25
4
Cotton underwear plus FR shirt and
FR pants plus double layer switching
coat and pants (4)
24-30 40
* ATPV is defined as the incident energy that would just cause the onset of a second
degree burn.
* EBT is defined as the highest incident energy which did not cause FR fabric breakopen
and did not exceed the second degree burn criteria. EBT is reported when ATPV cannot
be measured due to fabric breakopen.
71. 7171
Choosing Correct PPEChoosing Correct PPE
The equations in NFPA 70E-2004 provide
more accurate methods than tables for
determining PPE requirements. System
data and studies are required. The
equations are based upon limited fuse and
circuit breaker data.
72. 7272
Choosing Correct PPEChoosing Correct PPE
• Remember: PPE is the last line of
defense. PPE cannot prevent all
injuries and will only lessen the
impact of an arc flash. In many cases
the use of PPE has saved lives or
prevented serious injury.
73. 7373
Reducing The Arc Flash HazardReducing The Arc Flash Hazard
OSHA 1910.333 severely limits the
situations in which work is performed
on or near equipment or circuits that
are or may be energized.
74. 7474
Reducing The Arc Flash HazardReducing The Arc Flash Hazard
EQUIPMENT ALTERNATIVES
• Metal-Clad Switchgear
Structural design reduces the
possibility of arcing faults within the
enclosure.
75. 7575
Reducing The Arc Flash HazardReducing The Arc Flash Hazard
EQUIPMENT ALTERNATIVES
• Arc Resistant Switchgear
EEMAC Standard G14-1 defines the
requirements for arc resistant
switchgear. Includes robust design
and pressure relief vents.
76. 7676
Reducing The Arc Flash HazardReducing The Arc Flash Hazard
EQUIPMENT ALTERNATIVES
• Current-Limiter Power Circuit Breakers
Reduces the clearing time which
reduces the incident energy.
77. 7777
Reducing The Arc Flash HazardReducing The Arc Flash Hazard
EQUIPMENT ALTERNATIVES
• Current-Limiting Reactors
Reduces the magnitude of fault
current which reduces the incident
energy.
78. 7878
Reducing The Arc Flash HazardReducing The Arc Flash Hazard
EQUIPMENT ALTERNATIVES
• Zone Selective Interlocking of Circuit
Breakers
Deactivates the preset delay on the
circuit breaker closest to the fault,
which then trips with no intentional
delay.
79. 7979
Reducing The Arc Flash HazardReducing The Arc Flash Hazard
Whatever the analysis method or
proposed method of solution, each
work task must be analyzed assuming
worst case conditions.
80. 8080
Reference MaterialsReference Materials
• Standard for Electrical Safety in the Workplace, NFPA 70E 2004 Edition
• Controlling Electrical Hazards. OSHA Publication 3075, (2002). Also available as a 350 KB PDF,
71 pages. Provides a basic overview of electrical safety on the job, including information on how
electricity works, how to protect against electricity, and how OSHA can help.
• Electrical Safety: Safety and Health for Electrical Trades Student Manual. US Department of
Health and Human Services (DHHS), National Institute for Occupational Safety and Health
(NIOSH), Publication No. 2002-123, (2002, January), 1.7 MB PDF, 88 pages. This student
manual is part of a safety and health curriculum for secondary and post-secondary electrical
trades courses. It is designed to engage the learner in recognizing, evaluating, and controlling
hazards associated with electrical work. http://www.cdc.gov/niosh/pdfs/02-123.pdf
• Electrocutions Fatality Investigation Reports. National Institute for Occupational Safety and
Health (NIOSH) Safety and Health Topic. Provides information regarding hundreds of fatal
incidents involving electrocutions investigated by NIOSH and state investigators
• Working Safely with Electricity. OSHA Fact Sheet, 353 KB PDF, 2 pages. Provides safety
information on working with generators, power lines, extension cords, and electrical equipment.
http://www.osha.gov/OshDoc/data_Hurricane_Facts/elect_safety.pdf
• Lockout/Tagout. OSHA Fact Sheet, (2002), 212 KB PDF, 2 pages. A 92 KB PDF (Spanish
version) is also available. http://www.cdc.gov/nasd/docs/d001501-
d001600/d001514/d001514.html
• Lockout-Tagout Interactive Training Program. OSHA. Includes selected references for training
and interactive case studies. http://www.osha.gov/dts/osta/lototraining/index.htm
• NIOSH Arc Flash Awareness, NIOSH Publication No. 2007-116D
NIOSH Suggested Discussion Questions:
If one of the incidents in the video had happened to you, how would it have changed your life or the life of your family?
Have you ever experienced an arc flash? What happened? Did you change any safety practices in your work after the incident? What were they?
What are some behaviors that you can change to help prevent an arc flash incident to yourself and/or to your fellow electricians?
What PPE is recommended for your task? What are some of the excuses electricians use for not wearing appropriate PPE?
In, general, as electricians become more experienced, do you think their safety habits change? How?
After viewing this video, which, if any, of your safety work habits would you like to change?
Do you have any suggestions for your supervisor that you feel could help prevent an arc flash incident from happening to you or any of your co-workers?
What suggestions do you have for your company to help prevent arc flash incidents?
Arc Flash Awareness: DHHS(NIOSH) Publication No. 2007-116D
Ordering Information: Copies of NIOSH documents are available from:
NIOSH-Publications Dissemination
4676 Columbia Parkway
Cincinnati, OH 45226-1998
Fax: 513-533-8573, Phone: 1-800-35-NIOSH
Email: pubstaft@cdc.gov, website: www.cdc.gov/niosh
The NEC warning label should remind a qualified worker who intends to open the equipment for analysis or work that a serious hazard exists and that the worker should follow appropriate work practices and wear appropriate PPE for the specific hazard (a non qualified worker must not be opening the equipment).
The NEC 2002, section 110.16 requirement for labeling does not call for any quantification of the incident energy, however, some companies are choosing to provide more information on the arc flash label as shown above.
The manufacturer of the equipment is normally not aware of the site specific configuration of the power system at the point where the equipment will be connected or aware of the site specific tasks that will be evaluated.
The installer or the owner of the equipment must label the equipment.
Arc-flash protection is always based on the incident energy level on the person’s face and body at the working distance, not the incident energy on the hands or arms. The degree of injury in a burn depends on the percentage of a person’s skin that is burned. The head and body are a large percentage of total skin surface area and injury to these areas is much more life threatening than burns on the extremities.
Data required for this study is similar to data collected for typical short-circuit and protective device coordination studies, however it also requires information on low-voltage distribution and control equipment plus its feeders and large branch circuits. This information is used to determine the time of arc duration from the protective device time current curves.
Find the symmetrical root-mean-square (RMS) bolted fault current and X/R ratio at each point of concern for the 1.5 to 4 cycle case. This includes all locations where people could be working. It is important to include all cables. Conservatively high fault levels do not necessarily increase safety, they may reduce it. Don’t add a safety factor. Higher current can give shorter arc fault duration and the wrong energy value.
Lower fault currents often persist longer than higher currents because of the characteristic shape of most protective-device time-current curves.
Common causes of bolted faults:
1. Re-energizing without removing temporary grounding.
2. Incorrect connection of a parallel run of cables to a motor terminal box. Instead of connecting a-a, b-b, c-c; connections are a-b, a-b, c-c.
The arc fault current for each location where an arc flash hazard exists and the portion of that current that flows through the closest upstream protective device that will clear this fault must be determined.
The arc fault current depends primarily on the bolted fault current. The bolted fault current in the protective device can be found from the short-circuit study by looking at the detailed bus fault printout or looking at the fault levels that are “one-bus-away”. It is important to separate fault contributions from all other sources that will not flow through the protective device that will clear the fault. This includes alternate feeder and downstream motor fault contributions. The arc fault currents can then be calculated. The calculated arc fault current will be lower than the bolted fault current due to arc impedance, especially for applications less than 1000 V.
There are two types of protective devices in power distribution systems. These are fuses or circuit breakers. For fuses, the manufacturer’s time-current curves may include both melting and clearing time. If so, use the clearing time. If they show only the average melt time, add to that time 15% for times up to 0.03 seconds, and 10% above 0.03 seconds to determine total clearing time. For Current Limiting Fuses (CLF), use the maximum clearing time from the fuse time current curve if fault current is not in the current limiting range. The current limit point is at the 0.01 sec point on the fuse curve. For one to two times the limit point in amps, use 0.008 seconds (1/2 cycle). For over two times the limit point, use 0.004 seconds (1/4 cycle).
For circuit breakers with integral trip units, the manufacturer’s time-current curves include both the tripping time and the clearing time. The total clearing time as shown by the top band of the curve is the time value that should be used.
For relay operated circuit breakers, the relay curves show only the relay operating time in the time-delay region. For relays operating in their instantaneous region, allow 16 milliseconds on 60 Hz systems for operation. The circuit breaker opening time must be added to the relay time to give a total clearing time.
Equation 1 provides smaller values of the flash boundary because actual transformer ratings and power system impedances are used.
Equation must not be applied without an accurate up-to-date short circuit analysis at the point of exposure.
For transformers rated below .75 MVA, multiply transformer MVA by 1.25.
For each bus, document the system voltage and the class of equipment. For example, record whether the equipment is metal-enclosed switchgear or metal-clad switchgear.
IEEE 1584, Table - Classes of equipment and typical bus gaps
Arc-flash protection is always based on the incident energy level on the person’s face and body at the working distance, not the incident energy on the hands or arms. The degree of injury in a burn depends on the percentage of a person’s skin that is burned. The head and body are a large percentage of total skin surface area and injury to these areas is much more life threatening than burns on the extremities.
The equations in IEEE 1584-2002 are available in spreadsheet format. These equations have been incorporated into the packages of power system software vendors.
lg is the log10
Ia is arcing current in kA
K is -0.153 for open configurations, and
is -0.097 for box configurations
Ibf is bolted fault current for 3-ph symmetrical RMS in kA
V is system voltage in kV
G is the gap between conductors in mm
NFPA equations for “Open Air” and “Arc in a Box” are valid for 600 V or below.
NFPA equations for “Open Air” and “Arc in a Box” are valid for 600 V or below.
A simplified two-category approach is found in NFPA 70E-2000, Table F-1 of Part II, Appendix F NFPA. This table assures adequate PPE for electrical workers within facilities with large and diverse electrical systems. The clothing listed in Table F-1 fulfills the minimum FR clothing requirements of NFPA 70E-2000, Tables 3-3.9.1 and 3-3.9.2 NFPA and should be used with the other PPE appropriate for the Hazard/ Risk Category that is found in of NFPA 70E-2000, Table 3-3.9.2 NFPA.
A simplified two-category approach is found in NFPA 70E-2000, Table F-1 of Part II, Appendix F NFPA. This table assures adequate PPE for electrical workers within facilities with large and diverse electrical systems. The clothing listed in Table F-1 fulfills the minimum FR clothing requirements of NFPA 70E-2000, Tables 3-3.9.1 and 3-3.9.2 NFPA and should be used with the other PPE appropriate for the Hazard/ Risk Category that is found in of NFPA 70E-2000, Table 3-3.9.2 NFPA.
A simplified two-category approach is found in NFPA 70E-2000, Table F-1 of Part II, Appendix F NFPA. This table assures adequate PPE for electrical workers within facilities with large and diverse electrical systems. The clothing listed in Table F-1 fulfills the minimum FR clothing requirements of NFPA 70E-2000, Tables 3-3.9.1 and 3-3.9.2 NFPA and should be used with the other PPE appropriate for the Hazard/ Risk Category that is found in of NFPA 70E-2000, Table 3-3.9.2 NFPA.
A simplified two-category approach is found in NFPA 70E-2000, Table F-1 of Part II, Appendix F NFPA. This table assures adequate PPE for electrical workers within facilities with large and diverse electrical systems. The clothing listed in Table F-1 fulfills the minimum FR clothing requirements of NFPA 70E-2000, Tables 3-3.9.1 and 3-3.9.2 NFPA and should be used with the other PPE appropriate for the Hazard/ Risk Category that is found in of NFPA 70E-2000, Table 3-3.9.2 NFPA.
1910.333(a)(1)
"Deenergized parts." Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. Live parts that operate at less than 50 volts to ground need not be deenergized if there will be no increased exposure to electrical burns or to explosion due to electric arcs.
Note 1: Examples of increased or additional hazards include interruption of life support equipment, deactivation of emergency alarm systems, shutdown of hazardous location ventilation equipment, or removal of illumination for an area.
Note 2: Examples of work that may be performed on or near energized circuit parts because of infeasibility due to equipment design or operational limitations include testing of electric circuits that can only be performed with the circuit energized and work on circuits that form an integral part of a continuous industrial process in a chemical plant that would otherwise need to be completely shut down in order to permit work on one circuit or piece of equipment.