Arc Flash Hazards Construction Safety Association of Ontario

Arc Flash Hazards Construction Safety Association of Ontario
PB/RH -- March 3, 2009 ARC FLASH HAZARDS Construction Safety Association of Ontario Arc Flash Hazards This presentation was prepared by the Construction Safety Association of Ontario (CSAO) for use by the Ontario construction community. In 1979, the National Fire Protection Agency (NFPA) in the United States created NFPA 70E, which has evolved to become the North American standard for safe work practices for energized electrical work. In 2005, the Canadian Standards Association (CSA) began work to develop a new electrical safety standard, “CSA-Z462 Standard on Workplace Electrical Safety” that is to be harmonized with the NFPA 70E. Now the Canadian standard is complete and available from CSA. Order on-line at: or The examples and definitions in this slide presentation are taken from the CSA-Z462 Standard. You can purchase a of copy of NFPA 70E from the National Fire Protection Agency in the United States at or PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Purpose of this Presentation
Arc Flash Hazards PB/RH -- March 3, 2009 Purpose of this Presentation Introduction to: Hazard of arc flash New CSA Standard on electrical safety Arc flash prevention and protection Purpose of this Presentation The purpose of this presentation is to: Raise awareness about the specific electrical hazard of an arc flash, Introducing a new CSA Standard on workplace electrical safety, and Introduce some of the safe work practices related to arc flash hazards. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Arc Flash Hazards -- Construction Safety Association of Ontario
PB/RH -- March 3, 2009 Five Main Topics 1. Introduction to arc flash 2. Arc flash injuries 3. Codes and standards 4. Protective clothing and equipment 5. Prevention Main Topics The presentation covers 5 main topics: Introduction to arc flash Arc flash injuries Codes and standards Protective clothing and equipment Prevention. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Topic 1 – Introduction to Arc Flash
Arc Flash Hazards PB/RH -- March 3, 2009 Topic 1 – Introduction to Arc Flash Topic 1 – Introduction to Arc Flash PB/RH -- March 3, 2009 4 Construction Safety Association of Ontario

What is an Arc Flash Hazard?
Arc Flash Hazards PB/RH -- March 3, 2009 What is an Arc Flash Hazard? “. . . a dangerous condition associated with the release of energy caused by an electric arc.” What is an Arc Flash Hazard? Arc flash is defined by the CSA Z462 Standard on Workplace Electrical Safety as “a dangerous condition associated with the release of energy caused by an electric arc.” Arc flash is the explosive release of energy when electrical current jumps the distance from one conductor to another, or when it jumps from a conductor to ground. That jump is called an “arc”. “Flash” refers to the release of light and heat energy. Lightening is an example of an arc flash, when current jumps from sky to ground. The results are heat, light, and a pressure wave which you hear as thunder. In the workplace, arc flash can be deadly. It can happen anywhere you find energized electrical equipment or conductors. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

PB/RH -- March 3, 2009 What is an Electric Arc? An electric arc is a short circuit through the air. What is an Electric Arc? Simply put, an electric arc is a short circuit through the air. When insulation or isolation is breached or can no longer withstand the applied voltage between phase conductors or between a phase conductor and ground, the air between the conductors becomes ionized. Ionized air will conduct electricity and an arc fault occurs between those conductors. The power source will pump as much current into the arc fault as the supplying transformer, conductors, and arc impedance will allow until the fault is cleared by a protective device such as a fuse or circuit breaker or the fault burns itself out. The amount of energy released depends, in part, on the amount of energy in the circuit. The more energy, the more powerful the arc. Electric arcs produce some of the highest temperatures known to occur on earth. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Characteristics of an Electric Arc
Arc Flash Hazards PB/RH -- March 3, 2009 Characteristics of an Electric Arc An electric arc will oscillate and escalate if not constrained. A single-phase electric arc can engulf a second or third conductor in only two cycles. An electric arc’s current propels the arc away from the power source. Characteristics of an Electric Arc Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

PB/RH -- March 3, 2009 What Causes Arc Flash? Dust, impurities, corrosion, condensation, animals Spark discharge from: Accidental touching Dropping tools Over-voltages across narrow gaps Failure of insulating materials Equipment failure What Causes Arc Flash? Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

PB/RH -- March 3, 2009 What is Arc Blast? The flash causes an explosive expansion of air and metal. For example: When copper vapourizes it expands by a factor of 67,000. The blast produces dangerous: Pressure waves Sound waves Molten steel and shrapnel. What is Arc Blast? The intense heat from the arc causes the sudden expansion of air. The result is an explosive blast with very strong air pressure. Equipment and materials melt and are vapourized during an arc flash. When materials vapourize they expand in volume. For example, copper expands by a factor of 67,000 times* when it turns from a solid to a vapour. Water expands by a factor of 1670 times*. The dangers associated with this expansion are: High pressures, Sound, and Shrapnel in the form of molten steel and other fragments. *Source: Ralph Lee “Pressures Developed by Arcs”, IEEE Transactions on Industry Applications, Vol. 1A-23, No. 4. July/August 1987. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Video Clip 1 – Arc Flash Demo
Arc Flash Hazards PB/RH -- March 3, 2009 Video Clip 1 – Arc Flash Demo Video Clip 1 – Arc Flash Demo This is a video clip of a lab demonstration of the arc flash and blast resulting from a dead short across 3 phases, 480V. Click on the blue screen to play the video. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Arc Flash Events Electric arc Arc flash Arc blast
Arc Flash Hazards PB/RH -- March 3, 2009 Arc Flash Events Electric arc Arc flash Arc blast Arc Flash Events Compliments of Salisbury Electrical Safety L.L.C. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Forms of Arc Flash Energy
Arc Flash Hazards PB/RH -- March 3, 2009 Forms of Arc Flash Energy Noise Expansion Vaporization Thermal radiation Arc Energy Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Topic 2 – Arc Flash Injuries
Arc Flash Hazards PB/RH -- March 3, 2009 Topic 2 – Arc Flash Injuries Topic 2 – Arc Flash Injuries. Warning: some graphic pictures of injuries. PB/RH -- March 3, 2009 13 Construction Safety Association of Ontario

PB/RH -- March 3, 2009 Arc Flash Injuries Electric shock Severe burns Blindness Blast injuries Shrapnel wounds Lung blast injuries Ruptured eardrums Pressure wave injuries Arc Flash Injuries If an arc flash occurs near you, you can be: Electrocuted Burned Blinded Injured by the blast and suffer: Shrapnel wounds Lung blast injuries Ruptured eardrum Pressure wave injuries. Workers may never regain their quality of life and may even die from exposure to an arc flash event. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

PB/RH -- March 3, 2009 Severity Factors Power – amount of energy at the arc Distance – of the worker to the arc Time – duration of the arc exposure Severity Factors Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Video Clip 2 – “Not Safe at 18 inches”
Arc Flash Hazards PB/RH -- March 3, 2009 Video Clip 2 – “Not Safe at 18 inches” Video Clip 2 – “Not Safe at 18 inches” Westex Live Arc Flash Demonstration – click on the black screen to play the video. This is a 30 amp disconnect and the arc is going to be calculated to be well-below 4 calories, safe at 18 inches. You will see a violent arc that rockets out of the box and goes 6 or 7 feet away. You are clearly not safe in this incident at 18 inches from the arc gap because of the projection of the energy. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Video Clip 3 – “Not Safe Working Near”
Arc Flash Hazards PB/RH -- March 3, 2009 Video Clip 3 – “Not Safe Working Near” Video Clip 3 – “Not Safe Working Near” Westex Live Arc Flash Demonstration – click on the black screen to play the video. This is a 30 amp disconnect with Category 1 arc and it does something very surprising -- The hazard was not directly in front of the box. You will see that the arc leaves the box and travels down the bus bar at the bottom of the sled and blows a hole in the ultra-soft fabric wall at the back. This is a clear example of the hazards of working near energized electrical equipment – even 15 or 20 feet away. The arc did not come out of the box. It traveled down the bus bar and blew a hole in the rear wall. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Electric Shock Injury – Burn
Arc Flash Hazards PB/RH -- March 3, 2009 Electric Shock Injury – Burn Electric Shock Injury – Burn Arcing faults can release dangerous levels of radiant heat energy capable of causing severe burns and ignition of clothing. This can require painful skin grafting, lengthy rehabilitation, and can result in death. Recovery could take days, weeks, months of painful hospitalization. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Severe Burns from Arc Flash
Arc Flash Hazards PB/RH -- March 3, 2009 Severe Burns from Arc Flash Severe Burns from Arc Flash An electric arc is one of the hottest things on earth -- temperatures can reach 35,000° Fahrenheit (20,000° Celsius) This is four times the surface temperature of the sun. Exposure to these extreme temperatures both burns the skin directly and causes any flammable clothing (including underwear, etc.) and PPE to ignite, which significantly adds to the burn injury. Arc flash up to 35,000°F Sun 9,900°F Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Probability of Surviving Burns
Arc Flash Hazards PB/RH -- March 3, 2009 Probability of Surviving Burns Probability of Surviving Burns -- Burn Injury Statistics* According to statistics from the American Burn Association, the probability of survival decreases for older workers. As the age of the arc flash burn victim increases, the chance for survival decreases. In the United States, the majority of hospital admissions due to electrical accidents are from arc flash burns, not from shocks. Each year more than 2,000 people are admitted to burn centers with severe arc flash burns. Injuries due to arc flash are very severe. *Source: American Burn Association, Study; Revised March 2002. % Survival Age Range, Years Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

PB/RH -- March 3, 2009 Blindness Flash of light is so intense it can damage vision. Blindness Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Arc Flash Hazards PB/RH -- March 3, 2009 Shrapnel Wounds Shrapnel Wounds An arcing fault explosion can spray droplets of molten metal and shrapnel over a large area. Material and molten metal can hit the body at over 700 miles per hour. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Blast Lung Injury (BLI)
Arc Flash Hazards PB/RH -- March 3, 2009 Blast Lung Injury (BLI) Arc blast can cause inhalation injuries. For example: Inhaling high temperature copper vapour. More than 100 toxic substances can be found in the fumes. Blast Lung Injury (BLI) BLI + Burns = Greater chance of death Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

PB/RH -- March 3, 2009 Hearing Damage Arc blast at 2 feet 145 decibels Jet engine at 200 feet 132 decibels Pain threshold 130 decibels Hearing Damage Arcing faults can cause hearing loss from the sound blast. The sounds associated with the arc blast can exceed 160 dB. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Pressure Wave Injuries
Arc Flash Hazards PB/RH -- March 3, 2009 Pressure Wave Injuries Arc blast can throw a worker: Off a ladder Into nearby walls or equipment. 2000 lbs/ft2 pressure on the body can cause: Concussion Collapsed lungs Other internal injuries Pressure Wave Injuries Arcing faults can produce blast pressure waves that have thrown workers across the room or knocked them off ladders. Pressure on the chest can be higher than 2000 lbs/ sq. ft.* (pounds per square foot) *Source: Ralph Lee “Pressures Developed by Arcs”, IEEE Transactions on Industry Applications, Vol. 1A-23, No. 4. July/August 1987, page Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Topic 3 – Codes and Standards
Arc Flash Hazards PB/RH -- March 3, 2009 Topic 3 – Codes and Standards Topic 3 – Codes and Standards PB/RH -- March 3, 2009 26 Construction Safety Association of Ontario

PB/RH -- March 3, 2009 Standards US National Fire Protection Association -Standard NFPA 70E Canadian Standards Association -Standard Z-462 Institute of Electrical & Electronics Engineers -Standard 1584 Standards Canadian Electrical Code -Rule 2-306 Occupational Health & Safety Act -Applicable regulations US Occupational Safety & Health Administration Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

What is NFPA 70E? National Fire Protection Association
Arc Flash Hazards PB/RH -- March 3, 2009 What is NFPA 70E? National Fire Protection Association “Standard for Electrical Safety in the Workplace” Standard for electrical safety in United Sates “Harmonized” with CSA Z462 What is NFPA 70E? In the United States in 1979 the National Fire Protection Association (NFPA) created what is now called: “NFPA 70E Standard for Electrical Safety in the Workplace.” This US standard has evolved over the last 25 years to become the North American Standard for electrical safe work practices. The new 2009 edition is harmonized with the Canadian electrical safety Standard CSA Z462. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

PB/RH -- March 3, 2009 What is CSA Standard Z462? The standard for workplace electrical safety in Canada. “Harmonized” with NFPA 70E. What is CSA Standard Z462 A National Standard for workplace electrical safety titled CSA Z462 Standard on Workplace Electrical Safety is currently available. It was developed in parallel with the 2009 Edition of NFPA 70E and is harmonize with NFPA 70E as much as practicable for Canadian workplaces. CSA Z462 was developed by a voluntary Technical Committee with stakeholders (industry, labour, government) from around the country. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

CSA Standard Z462 addresses:
Arc Flash Hazards PB/RH -- March 3, 2009 CSA Standard Z462 addresses: Electrical Safety Program Arc Flash Hazard Analysis Flash Protection Boundary Fault Current Calculations Arc Fault Clearing Time Incident Energy Exposure Required PPE CSA Standard Z462 addresses: Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Arc Flash Hazards PB/RH -- March 3, 2009 What is IEEE Standard 1584? Institute of Electrical and Electronics Engineers Offers a method for performing arc flash hazard calculations. What is IEEE Standard 1584 The IEEE, a non-profit organization, is a leading professional association for the advancement of technology. The full name of the IEEE is the Institute of Electrical and Electronics Engineers, Inc., although the organization is referred to by the letters I-E-E-E and pronounced Eye-triple-E IEEE Standard 1584 “Guide to Performing Arc Flash Hazard Calculations” provides a method for determining the arc flash hazard distance and incident energy that workers may be exposed to from electrical equipment. The IEEE method is a different method (from NFPA 70E and CSAZ462) of conducting arc flash calculations. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

What is CEC Rule 2-306? Canadian Electrical Code
Arc Flash Hazards PB/RH -- March 3, 2009 What is CEC Rule 2-306? Canadian Electrical Code “Rule Shock and Flash Protection” A requirement for field-marking electrical equipment to warn persons of potential electric shock and arc flash hazards. What is CEC Rule 2-306? The Canadian Electrical Code (CEC) has a rule that improves safety for workers by requiring special field marking of electrical equipment in the workplace to warn about: Potential electric shock hazards, and Arc flash hazards. The CEC is an installation code, so the responsibility for marking is with the installer. The rule is as follows: Rule Shock and flash protection Electrical equipment such as switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centres that are installed in other than dwelling units and are likely to require examination, adjustment, servicing, or maintenance while energized shall be field marked to warn persons of potential electric shock and arc flash hazards. The marking referred to in Subrule (1) shall be located so that it is clearly visible to persons before examination, adjustment, servicing, or maintenance of the equipment. Generally, “field marked” means the equipment supplier does not have the responsibility to mark the equipment. The installer in the field would be required to provide the markings when the installation is done. This labeling is required for all new or modified installations after May 1, 2006. Labels only require providing a warning of the potential for shock and arc flash. The requirement to perform an analysis to determine energy incident levels does not come from this rule. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Required Warning Label
Arc Flash Hazards PB/RH -- March 3, 2009 Required Warning Label Sample label that complies with CEC Rule Required Warning Labels The labels shall be of a permanent-type design (ie. a lamicoid or self adhesive label or one supplied by the manufacturer) and shall be mounted in a visible position. More than one label may be required, depending on the size and design of the equipment, and as determined by the inspector. Suggested wording is: “Danger” or “Warning” at the top, then “Potential Electric Shock or Arc Flash Hazard Exists” below. A label provided by a manufacturer will be acceptable in most instances. The contractor is responsible to check with the inspection department prior to installing any labels if they have any questions as to whether it is acceptable. Should a contractor wish to have many labels made up by an outside company for their own personal supply (which is recommended for consistency and pre-approval) the design and wording of such labels should be reviewed by the inspection department first to ensure they are acceptable. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Optional Warning Label
Arc Flash Hazards PB/RH -- March 3, 2009 Optional Warning Label Optional Warning Label Workers can better protect themselves if labels contain additional information from the results of an arc flash calculation. If work must be done where an arc flash hazard exists, it only makes sense to keep the results of the analysis in maintenance records. Taking that one step further, the information can be summarized on the label to make it readily available to workers and supervisors. Adding a maintenance file record number and date to the warning label, gives workers the ability to check and verify if the label recommendations are still valid. It also assists in ensuring the electrical safety program remains up to date. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Topic 4 – Protective Clothing and Equipment
Arc Flash Hazards PB/RH -- March 3, 2009 Topic 4 – Protective Clothing and Equipment Topic 4 – Protective Clothing and Equipment Topic 4 discusses some of the protective clothing and equipment used to prevent and/or minimize arc flash injuries. PB/RH -- March 3, 2009 35 Construction Safety Association of Ontario

Flame-Resistant (FR) Clothing
Arc Flash Hazards PB/RH -- March 3, 2009 Flame-Resistant (FR) Clothing Protects a worker from receiving severe burns if the worker is exposed to a flame. Is self-extinguishing when the source of the flame is removed. Flame-Resistant (FR) Clothing Flame-resistant (or FR) clothing is the most common and industry-accepted PPE that protects the body from burns due to a flame. The beneficial characteristic of FR clothing is that it will not continue to burn on its own when a flame source is removed. This is achieved by treating the fibre of a cloth with flame-retardant chemicals, or by using fibres in the cloth that are inherently flame resistant. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

PB/RH -- March 3, 2009 What is a Calorie? A calorie is the amount of heat needed to raise the temperature of one gram of water by 1°C. Thermal energy is measured in calories/cm². What is a Calorie? A calorie is a unit of measurement for energy. It approximates the energy needed to raise the temperature of 1 gram of water by 1 °C at 1 atmosphere pressure. Second Degree Burn = 1.2 cal/cm² for more than 1 second. For example: By holding your finger in the blue part of the flame of a lighter for 1 second, a square centimetre of your finger will be exposed to about 1.2 calories/cm². . 1.2 calories/cm² = Holding your finger in the blue part of the flame for one second. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

FR Rated Clothing Limit the ‘Incident Energy’ level of the
Arc Flash Hazards PB/RH -- March 3, 2009 FR Rated Clothing Limit the ‘Incident Energy’ level of the arc flash to 1.2 cal/cm² against the worker’s chest. Look for a label that states: 1506 approval (ASTM F1506) Arc rating of the garment. All materials in the garment should be FR Rated: Thread Buttons Insulation Zippers, etc. FR Rated Clothing An arc flash analysis will identify the level of incident energy available and thereby the level of protection the worker requires. ASTM F1506* is a standard that was developed to give minimum performance specifications for protective clothing. CSA Z462 uses a hazard risk category system to identify the incident energy a worker would be exposed while performing a task. The category level (0 to 4) is used to identify a level of protection for the worker, which simplifies PPE choice. *ASTM F1506 = Standard Performance Specification for Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Arc and Related Thermal Hazards. Photo compliments of Salisbury Electrical Safety L.L.C. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Typical PPE Requirements
Arc Flash Hazards PB/RH -- March 3, 2009 Typical PPE Requirements Hazard/Risk Category Eye protection, ear canal inserts, long sleeve shirt and pants Arc rated clothing Face & Head Protection Flash Suit Hood  1 2 3 4 Typical PPE Requirements This information is based on the 2008 edition of CSA Z462 Standard, Workplace Electrical Safety, Table 5 Hazard/risk categorization of protective clothing and PPE. More information on PPE selection is available in the table and the accompanying notes. In most applications clothing and PPE must be either be FR rated or arc-flash rated. Note the arc rating associated with each hazard/risk category. Do not wear materials such as nylon and polyester that can melt. Non-FR-rated undergarments (and PPE) may catch fire even when arc-rated clothing worn overtop survives an arc flash. All categories 0 – 4 require: either safety glasses or safety goggles, ear canal inserts; and, long sleeve shirt and pants that are non-melting, arc-rated to ASTM F-1506 or untreated natural fibre. Category 1 requires clothing to be arc-rated to ASTM F Hard hat and arc rated face shield are also required as additional head and eye protection. Face shields must have wrap-around guarding to protect the forehead, ears, and neck. Some category 2 tasks require the use of a flash suit hood in place of an arc-rated face shield; however, there is also an option to substitute the flash suit hood for a combination of a face shield with a balaclava (sock hood). Both the face shield and balaclava must be arc rated. Categories 3 and 4 will require the use of a flash suit hood. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Typical Protective Clothing
ORAC Presentation on Arc Flash PB/RH -- March 3, 2009 Typical Protective Clothing Hazard/Risk Category Clothing Description Required Minimum Clothing Arc Rating Non-melting, flammable material with fabric weight of at least 4.5 oz/yd2 Not applicable 1 Arc-rated FR shirt + FR pants or FR coveralls 4 calories/cm² 2 8 calories/cm² 3 Arc-rated FR shirt + FR pants or FR coveralls, and Arc-rated flash suit, the layered system must meet the required minimum rating. 25 calories/cm² 4 40 calories/cm² Typical Protective Clothing This information is based on the 2008 edition of CSA Z462 Standard, Workplace Electrical Safety, Table 6 Protective Clothing Characteristics. Hazard/risk category 0: Non-melting flammable material with fabric weight of at least 4.5 oz/yd2. Hazard/risk category 1: Arc-rated FR shirt + FR pants or FR coveralls. Hazard risk category 2: Arc-rated FR shirt + FR pants or FR coveralls. Hazard/risk category 3: Arc-rated FR shirt + FR pants or FR coveralls, and Arc-rated flash suit, selected so the layered system meets the required minimum rating. Hazard/risk category 4: Arc-rated FR shirt + FR pants or FR coveralls, and Arc-rated flash suit, selected so the layered system meets the required minimum rating. Do not wear materials such as nylon and polyester that can melt. Non-FR-rated undergarments (and PPE) may catch fire even when arc-rated clothing worn overtop easily survives an arc flash. Important Note: FR clothing will not also be arc-rated unless it meets ASTM F1506. See Topic 4 – Protective Clothing and Equipment. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Presented by Ray Hokins, Project Coordinator Construction Safety Association of Ontario

PB/RH -- March 3, 2009 Synthetic Clothing Synthetic clothing that melts shall not be worn, such as: Acetate Nylon Polyester Polypropylene Spandex. Synthetic Clothing Non-rated clothing, and other PPE that can melt or catch fire, exposes the worker to serious burn injury. Even when arc rated clothing easily survives an arc flash, non FR-rated clothing, including undergarments and other PPE that can melt or catch fire, have caused workers to be severely injured when it either burned or melted on the workers skin. The result is extremely painful and lengthy hospitalization and rehabilitation, and permanent changes to their quality of life. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Arc Flash Rated PPE Required minimum clothing:
Arc Flash Hazards PB/RH -- March 3, 2009 Arc Flash Rated PPE Required minimum clothing: Non-melting, flammable material, Fabric weight of at least 4.5 oz/yd. PPE must also provide arc flash protection: Face shield Gloves, etc. Arc Flash PPE There is no CSA certification for arc flash resistant PPE. Instead, ASTM F1506 is the certification for arc flash resistant clothing. Face shields commonly used for grinding and cutting are not arc flash rated and may melt. Arc flash resistant face shields must meet ASTM F2178 specifications to comply with NFPA 70E (and CSA Z ) for arc flash protection. Hard hats, safety glasses, leather work boots, and leather gloves, for example, may either be inherently flame resistant or designed to another standard that provides some protection against flammability, ignition, and melting. The material used in manufacturing makes a difference. Generally, ear canal inserts made of PVC are more flame resistant than inserts made from polyurethane. Photo compliments of Salisbury Electrical Safety L.L.C. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Video Clip 4 – 100% Cotton Clothing
Arc Flash Hazards PB/RH -- March 3, 2009 Video Clip 4 – 100% Cotton Clothing Video Clip 4 – 100% Cotton Clothing Westex Live Arc Flash Demonstration – click on the black screen to play the video. The arc comes out of the box, hits the ground, and rolls out at least 10 feet. The clothing is instantly on fire – pants and shirt – from the shoes right on up. This is a very fierce fire. Clearly illustrates the fallacy of wearing non flame-resistant pants on the assumption that the arc will hit you on the chest. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Video Clip 5 – Polyester/Cotton Clothing
Arc Flash Hazards PB/RH -- March 3, 2009 Video Clip 5 – Polyester/Cotton Clothing Video Clip 5 – Polyester/Cotton Clothing Westex Live Arc Flash Demonstration – click on the black screen to play the video. You can see that the garments are basically instantly on fire, including the pants. Before the molten metal has entirely cleared the air, the garments are on fire. Look at the large amount of molten polyester that is falling away from the shirt. This kind of an incident would result in a minimum of probably 60-65% body burn. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Video Clip 6 – FR Clothing
Arc Flash Hazards PB/RH -- March 3, 2009 Video Clip 6 – FR Clothing Video Clip 6 – FR Clothing Westex Live Arc Flash Demonstration – click on the black screen to play the video. Clothing on manikin: Pant = INDURA™ Ultra Soft ™ Style 451 9oz; After 100 industrial launderings Shirt = INDURA™ Ultra Soft ™ Style 301 7oz; After 100 industrial launderings The arc completely envelopes the front and some of the back of the manikin. A massive amount of molten metal is thrown out. The arc is beyond the rating of the garments. The garments have had 100 industrial launderings and yet, no fire on the garments. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

FR Clothing Can Be Layered
ORAC Presentation on Arc Flash PB/RH -- March 3, 2009 FR Clothing Can Be Layered Increases level of protection. May be lighter than a single heavy garment. Manufacturer must provide the new combined arc rating afforded by layering. FR Clothing Can Be Layered Arc rated clothing may be layered to increase the level of protection. For example, wearing FR coveralls over FR shirt and FR pants. Layered clothing is more versatile and may result in garments that are lighter than if a single heavy garment were used. The manufacturer must provide information on the increased protection afforded by layering their clothing. The new arc flash rating of the layering must however be verified by the manufacturer through testing. Photo compliments of Salisbury Electrical Safety L.L.C. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Presented by Ray Hokins, Project Coordinator Construction Safety Association of Ontario

Arc Flash Hazards PB/RH -- March 3, 2009 When Purchasing PPE Tell the supplier that you need arc flash rated PPE and clothing. PPE must have some resistance to: Flame Ignition Melting. obtain PPE from a known and trusted supplier. When Purchasing PPE As mentioned, there is no CSA certification for arc flash resistant PPE. Instead, ASTM F1506 is the certification for arc flash resistant clothing. Table 5 in CSA Z462 Protective Clothing and Personal Protective Equipment (PPE) mentions protective equipment that must be FR rated, however it also identifies a number of the items have no FR requirement stated. Purchasers should obtain PPE from a known and trusted supplier. Photo compliments of Salisbury Electrical Safety L.L.C. Not all FR clothing is tested to ASTM F1506 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Topic 5 – Prevention 48 PB/RH -- March 3, 2009 Arc Flash Hazards
Construction Safety Association of Ontario

Tasks with Potential for Arc Flash
Arc Flash Hazards PB/RH -- March 3, 2009 Tasks with Potential for Arc Flash Operating a switch or circuit breaker Inserting or removing a circuit breaker Opening an enclosure door Removing a cover (bolted or hinged) Testing for voltage Tasks with Potential for Arc Flash Always de-energize equipment before working on it, whenever possible; however, workers should check if the task of operating the disconnect switch might require some arc flash protection. In each task: Worker is interacting with energized equipment. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

Arc Flash Hazard Analysis
ORAC Presentation on Arc Flash PB/RH -- March 3, 2009 Arc Flash Hazard Analysis Conduct a Flash Hazard Analysis to determine the Flash Protection Boundary Incident Energy exposure Type and arc rating of PPE If work must be done on or near energized electrical equipment, identify the potential for arc flash. Arc Flash Hazard Analysis Flash Protection Boundary is “an approach limit at a distance from exposed live parts within which a person could receive a second-degree burn if an electrical arc flash were to occur.”* Methods and sample calculations for Flash Protection Boundary can be found in CSA Z462 Workplace Electrical Safety and IEEE 1584 Guide for Performing Arc Flash Calculations. Incident Energy exposure is “the amount of energy impressed on a surface, a certain distance from the source, generated during an arc flash.”* Key variables are the available fault current, the expected arcing fault duration, and the worker’s distance from the arc. Methods and sample calculations for Incident Energy can be found in CSA Z462 and IEEE 1584. Protective Equipment Tables in CSA Z462 can be used to determine PPE. *Source: CSA Z462 Workplace Electrical Safety Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Presented by Ray Hokins, Project Coordinator Construction Safety Association of Ontario

CONTROLLING ARC FLASH HAZARDS At the Source
ORAC Presentation on Arc Flash PB/RH -- March 3, 2009 CONTROLLING ARC FLASH HAZARDS At the Source Reduce the fault clearing time. Reduce the short-circuit current. Improve equipment maintenance. Controlling Arc Flash Hazards – At the Source Reduce the fault clearing time: Any fault should be cleared quickly to reduce the duration and magnitude of the heat released by the short circuit currents. Engineering practices can obtain faster fault clearing times. Reduce the short-circuit current by using: Current limiting fuses/breakers Current limiting reactors, High resistance grounding. Ways of improving equipment maintenance and methods: Employ an equipment maintenance program accommodating manufacturers recommendations. Maintain equipment maintenance records. Conduct infrared scanning. Identify and label equipment that poses flash hazard. Confirm single-line diagrams for accuracy and available fault current. Reference: 2007 CSA/IAPA Workplace Electrical Safety Conference – Presentation: Methods of Arc Flash Calculation and Mitigation Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Presented by Ray Hokins, Project Coordinator Construction Safety Association of Ontario

CONTROLLING ARC FLASH HAZARDS At the Source
ORAC Presentation on Arc Flash PB/RH -- March 3, 2009 CONTROLLING ARC FLASH HAZARDS At the Source Use flash-resistant equipment. Controlling Arc Flash Hazards – At the Source These disconnect switch-plugs have been designed with built-in flash-protection. Photos courtesy of Meltric Corporation Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Presented by Ray Hokins, Project Coordinator Construction Safety Association of Ontario

CONTROLLING ARC FLASH HAZARDS Along the Path
PB/RH -- March 3, 2009 CONTROLLING ARC FLASH HAZARDS Along the Path Increase the working distance. Reduce the energy exposure. Use hinged doors instead of bolted doors to eliminate the risk of bolts falling into the panel. Work de-energized. Controlling Arc Flash Hazards – Along the Path Increasing the distance between electrical conductors and the worker greatly reduces the arc incident energy and the arc blast force. Remote racking of breakers/remote switching -- New high voltage equipment can be ordered with the breaker “open” and “close” switches remote from the breaker unit. These could be placed in a separate control panel or remote room. Older switchgears can be retrofitted with remote control switches. Use hot sticks to operate fuses and switches. These provide insulation from the high voltage parts. They also allow the worker to maintain increased working distance, so the incident energy is less. Placing distance between electrical conductors and the worker greatly reduces the arc incident energy and the arc blast force. See CSA Z462 Table 1 for distances associated with various system voltages. Reduce the energy exposure by using: Arc resistant switchgear, Arc shield when racking a circuit breaker. Use hinged doors instead of bolted doors. Hinged doors eliminate the risk of bolts falling into the panel. Reference: 2007 CSA/IAPA Workplace Electrical Safety Conference – Presentation: Methods of Arc Flash Calculation and Mitigation Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

CONTROLLING ARC FLASH HAZARDS At the Worker
PB/RH -- March 3, 2009 CONTROLLING ARC FLASH HAZARDS At the Worker Energized electrical work permit Barriers Training and skills Job briefings PPE Tools Controlling Arc Flash Hazards – At the Worker Energized electrical work permit: is used as part of an overall occupational health and safety management system, ensures all aspects of the job and the associated hazards are addressed for the protection of the worker and the plant facilities, before work begins, provides for documentation of due diligence on behalf of the supervisor and the employer. Barriers are intended to prevent contact with equipment or live parts or to prevent unauthorized access to a work area. Placing a barrier such as a closed door or a portable shield would also limit the arc flash exposure. Training and skills – keeping workers current about good work practices protects the worker from electrical hazards. Job briefings before each job should cover hazards, work procedures, special precautions, energy source controls, and PPE requirements. Personal Protective Equipment – PPE provides varying levels of protection from arc flash injury. The main purpose of arc flash rated clothing is to limit burn injury to a maximum level that will heal (second degree). It is important that workers understand the use, care, and limitations. Employers should ensure that workers have adequate understanding and training in the use of PPE. PPE must not be treated as a substitute for common sense and safe work practices. Use insulated tools and handling equipment to prevent incidental contact: Hand tools; Fuse or fuse holding equipment; Ropes and handlines; Fibreglass-reinforced plastic rods; Portable ladders; Protective shields; Rubber insulating equipment; Voltage rated plastic guard equipment; Physical or mechanical barriers. Remember that it is ALWAYS preferable to work on de-energized equipment. Photo compliments of Salisbury Electrical Safety L.L.C. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

PB/RH -- March 3, 2009 Prevention Summary Include Electrical Safety in your Occupational Health and Safety Management Program. Use an electrical work permit system. Conduct regular equipment maintenance and label equipment that poses a flash hazard. Confirm single-line diagrams for accuracy and available fault current. Maintain documentation process. Provide training and job briefings. Conduct periodic safety audits. Prevention Summary Occupational health and safety management system (OHSMS) is a living process that is continually revisited to address the changing workplace. It is improved as new work methods are discovered and experience is built upon. One method of ensuring the OHSMS is maintained and up to date is to provide for a periodic audit of the management system. For more detailed information about preventing arc flash hazards, refer to CSA Z462 Workplace Electrical Safety. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009 Construction Safety Association of Ontario

It is ALWAYS preferable to work on de-energized equipment.
Arc Flash Hazards PB/RH -- March 3, 2009 ARC FLASH HAZARDS It is ALWAYS preferable to work on de-energized equipment. Arc Flash Hazards It is ALWAYS preferable to work on de-energized equipment. PB/RH -- March 3, 2009 56 Construction Safety Association of Ontario

Arc Flash Hazards Construction Safety Association of Ontario

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