ARC FLASH HAZARDS Construction Safety Association of Ontario

ARC FLASH HAZARDS Construction Safety Association of Ontario 1 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 2 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 3 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Topic 1 – Introduction to Arc Flash 4 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. ” 5 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

What is an Electric Arc? 6 An electric arc is a short circuit through the air. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Characteristics of an Electric Arc 7 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. Arc Flash Hazards -- 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 8 Over-voltages across narrow gaps Failure of insulating materials Equipment failure Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

What is Arc Blast? 1. The flash causes an explosive expansion of air and metal. – For example: When copper vapourizes it expands by a factor of 67, 000. 2. The blast produces dangerous: – Pressure waves – Sound waves – Molten steel and shrapnel. 9 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Video Clip 1 – Arc Flash Demo 10 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Arc Flash Events Electric arc Arc flash Arc blast Compliments of Salisbury Electrical Safety L. L. C. 11 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Forms of Arc Flash Energy 12 Noise Expansion Vaporization Thermal radiation Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Topic 2 – Arc Flash Injuries 13 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 14 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Severity Factors 1. Power – amount of energy at the arc 2. Distance – of the worker to the arc 3. Time – duration of the arc exposure 15 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Video Clip 2 – “Not Safe at 18 inches” 16 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Video Clip 3 – “Not Safe Working Near” 17 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Electric Shock Injury – Burn 18 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Severe Burns from Arc Flash Arc flash Sun 19 up to 35, 000°F 9, 900°F Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

% Survival Probability of Surviving Burns Age Range, Years 20 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Blindness Flash of light is so intense it can damage vision. 21 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Shrapnel Wounds Material and molten metal can hit the body at over 700 miles per hour. 22 Arc Flash Hazards -- Construction Safety Association of Ontario 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. BLI + Burns = Greater chance of death 23 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Hearing Damage 24 Arc blast at 2 feet 145 decibels Jet engine at 200 feet 132 decibels Pain threshold 130 decibels Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Pressure Wave Injuries Arc blast can throw a worker: – Off a ladder – Into nearby walls or equipment. 2000 lbs/ft 2 pressure on the body can cause: – Concussion – Collapsed lungs – Other internal injuries 25 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Topic 3 – Codes and Standards 26 PB/RH -- March 3, 2009

Standards US National Fire Protection Association -Standard NFPA 70 E Canadian Standards Association -Standard Z-462 Canadian Electrical Code -Rule 2 -306 US Occupational Safety & Health Administration 27 Institute of Electrical & Electronics Engineers -Standard 1584 Occupational Health & Safety Act -Applicable regulations Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

What is NFPA 70 E? National Fire Protection Association “Standard for Electrical Safety in the Workplace” • Standard for electrical safety in United Sates • “Harmonized” with CSA Z 462 28 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

What is CSA Standard Z 462? 29 The standard for workplace electrical safety in Canada. “Harmonized” with NFPA 70 E. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

CSA Standard Z 462 addresses: Electrical Safety Program Arc Flash Hazard Analysis – Flash Protection Boundary – Fault Current Calculations – Arc Fault Clearing Time – Incident Energy Exposure 30 Required PPE Arc Flash Hazards -- Construction Safety Association of Ontario 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. 31 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

What is CEC Rule 2 -306? Canadian Electrical Code “Rule 2 -306 Shock and Flash Protection” 32 A requirement for field-marking electrical equipment to warn persons of potential electric shock and arc flash hazards. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Required Warning Label 33 Sample label that complies with CEC Rule 2 -306. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Optional Warning Label 34 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Topic 4 – Protective Clothing and Equipment 35 PB/RH -- March 3, 2009

Flame-Resistant (FR) Clothing 36 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. Arc Flash Hazards -- 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. 1. 2 calories/cm² = Holding your finger in the blue part of the flame for one second. 37 Arc Flash Hazards -- Construction Safety Association of Ontario 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 F 1506) – Arc rating of the garment. All materials in the garment should be FR Rated: – Thread – Buttons – Insulation – Zippers, etc. 38 Photo compliments of Salisbury Electrical Safety L. L. C. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Typical PPE Requirements Hazard/Ri sk Category Eye protection, ear canal inserts, long sleeve shirt and pants 0 1 2 3 4 39 Arc rated clothing Face & Head Protection Arc Flash Hazards -- Construction Safety Association of Ontario Flash Suit Hood PB/RH -- March 3, 2009

Typical Protective Clothing 40 Hazard/Ri sk Category Clothing Description Required Minimum Clothing Arc Rating 0 Non-melting, flammable material with fabric weight of at least 4. 5 oz/yd 2 Not applicable 1 Arc-rated FR shirt + FR pants or FR coveralls 4 calories/cm² 2 Arc-rated FR shirt + FR pants or FR coveralls 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. Arc Flash Hazards -- Construction Safety Association of Ontario Arc-rated FR shirt + FR pants or FR 25 calories/cm² PB/RH -- March 3, 2009 40 calories/cm²

Synthetic Clothing Synthetic clothing that melts shall not be worn, such as: – Acetate – Nylon – Polyester – Polypropylene – Spandex. 41 Arc Flash Hazards -- Construction Safety Association of Ontario 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. Photo compliments of Salisbury Electrical Safety L. L. C. 42 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Video Clip 4 – 100% Cotton Clothing 43 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Video Clip 5 – Polyester/Cotton Clothing 44 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Video Clip 6 – FR Clothing 45 Arc Flash Hazards -- Construction Safety Association of Ontario 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. Photo compliments of Salisbury Electrical Safety L. L. C. 46 Arc Flash Hazards -- Construction Safety Association of Ontario 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 Photo compliments of Salisbury Electrical Safety L. L. C. trusted supplier. Not all FR clothing is tested to ASTM F 1506 47 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Topic 5 – Prevention 48 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 In each task: Worker is interacting with energized equipment. 49 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Arc Flash Hazard Analysis If work must be done on or near energized electrical equipment, identify the potential for arc flash. 50 Conduct a Flash Hazard Analysis to determine the Ø Flash Protection Boundary Ø Incident Energy exposure Ø Type and arc rating of PPE Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

CONTROLLING ARC FLASH HAZARDS At the Source 51 Reduce the fault clearing time. Reduce the short-circuit current. Improve equipment maintenance. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

CONTROLLING ARC FLASH HAZARDS At the Source Use flash-resistant equipment. These disconnect switch-plugs have been designed with built-in flash-protection. Photos courtesy of Meltric Corporation 52 Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

CONTROLLING ARC FLASH HAZARDS Along the Path Increase Reduce the working distance. the energy exposure. Use hinged doors instead of bolted doors to eliminate the risk of bolts falling into the panel. Work 53 de-energized. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

CONTROLLING ARC FLASH HAZARDS At the Worker Energized electrical work permit Barriers Training Job and skills briefings PPE Tools 54 Photo compliments of Salisbury Electrical Safety L. L. C. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

Prevention Summary 55 1. Include Electrical Safety in your Occupational Health and Safety Management Program. 2. Use an electrical work permit system. 3. Conduct regular equipment maintenance and label equipment that poses a flash hazard. 4. Confirm single-line diagrams for accuracy and available fault current. 5. Maintain documentation process. 6. Provide training and job briefings. 7. Conduct periodic safety audits. Arc Flash Hazards -- Construction Safety Association of Ontario PB/RH -- March 3, 2009

It is ALWAYS ARC FLASH HAZARDS preferable to work on de-energized equipment. 56 PB/RH -- March 3, 2009