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Csao Arc Flash Hazards

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  • POWERFUL stuff that 'old school' electricians etc REALLY need to read
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  • Arc Flash Hazards This presentation was prepared by the Construction Safety Association of Ontario (CSAO) for use by the Ontario construction community. The examples and definitions are taken from the U.S. National Fire Protection Association’s “ NFPA 70E Standard for Electrical Safety in the Workplace.” 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 standard, “ CSA-Z462 Standard on Workplace Electrical Safety ” that will be harmonized with the NFPA 70E which should be completed in 2009. You can purchase a of copy of NFPA 70E from the National Fire Protection Agency in the United States at www.nfpa.org or 1-800-344-3555.
  • Transcript

    • 1. ARC FLASH HAZARDS Construction Safety Association of Ontario
    • 2. Purpose of this Presentation
      • Introduction to:
        • Hazard of arc flash
        • New CSA Standard on electrical safety
        • Arc flash prevention and protection
    • 3. Five Main Topics
      • 1. Introduction to arc flash
      • 2. Arc flash injuries
      • 3. Codes and standards
      • 4. Protective clothing and equipment
      • 5. Prevention
    • 4. Topic 1 – Introduction to Arc Flash
    • 5. What is an Arc Flash Hazard?
      • “ . . . a dangerous condition associated with the release of energy caused by an electric arc.”
    • 6. What is an Electric Arc?
      • An electric arc is a short circuit through the air.
    • 7. 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.
    • 8. Video Clip 1 – Arc Flash Demo
    • 9.
      • Electric arc Arc flash Arc blast
      Arc Flash Events Compliments of Salisbury Electrical Safety L.L.C.
    • 10. 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
    • 11.
      • 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
    • 12. Arc Energy
      • Noise
      • Expansion
      • Vaporization
      • Thermal radiation
    • 13. Topic 2 – Arc Flash Injuries
    • 14. Arc Flash Injuries
      • Electric shock
      • Severe burns
      • Blindness
      • Blast injuries
        • Shrapnel wounds
        • Lung blast injuries
        • Ruptured eardrums
        • Pressure wave injuries
    • 15.
      • Power – amount of energy at the arc
      • Distance – of the worker to the arc
      • Time – duration of the arc exposure
      Severity Factors
    • 16. Video Clip 2 – “Not Safe at 18 inches”
    • 17. Video Clip 3 – “Not Safe Working Near”
    • 18. Electric Shock Injury – Burn
    • 19. Severe Burns from Arc Flash 9,900 °F Sun up to 35,000 °F Arc flash
    • 20. Probability of Surviving Burns % Survival Age Range, Years
    • 21. Blindness
      • Flash of light is so intense it can damage vision.
    • 22. Shrapnel Wounds Material and molten metal can hit the body at over 700 miles per hour.
    • 23. 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
    • 24. Hearing Damage 130 decibels Pain threshold 132 decibels Jet engine at 200 feet 145 decibels Arc blast at 2 feet
    • 25. 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
    • 26. Topic 3 – Codes and Standards
    • 27. Standards US Occupational Safety & Health Administration US National Fire Protection Association -Standard NFPA 70E Institute of Electrical & Electronics Engineers -Standard 1584 Canadian Standards Association -Standard Z-462 (in 2009) Occupational Health & Safety Act -Applicable regulations Canadian Electrical Code -Rule 2-306
    • 28. What is NFPA 70E? N ational F ire P rotection A ssociation “ Standard for Electrical Safety in the Workplace”
    • 29. What is CSA Standard Z462?
      • C anadian S tandards A ssociation
      • Standard for electrical safety in Canadian workplaces.
      • Will be “harmonized” with NFPA 70E.
      • To be completed in 2009.
    • 30.
      • 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 will address:
    • 31.
      • I nstitute of E lectrical and E lectronics E ngineers
      • A guide for performing arc flash hazard calculations.
      What is IEEE Standard 1584?
    • 32. What is CEC Rule 2-306?
      • C anadian E lectrical C ode
      • “ Rule 2-306 Shock and Flash Protection”
      • A requirement for field-marking electrical equipment to warn persons of potential electric shock and arc flash hazards.
    • 33.
      • Sample label that complies with CEC Rule 2-306.
      Required Warning Label
    • 34. Optional Warning Label
    • 35. Topic 4 – Protective Clothing and Equipment
    • 36. 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.
      • Must be worn to limit the ‘Incident Energy’ level of the arc flash to 1.2 cal/cm ² against the worker’s chest.
    • 37. 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/cm ².
      1.2 calories/cm ² = Holding your finger in the blue part of the flame for one second.
    • 38.
      • 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 Photo compliments of Salisbury Electrical Safety L.L.C.
    • 39. Synthetic Clothing
      • Synthetic clothing that melts shall not be worn, such as:
        • Acetate
        • Nylon
        • Polyester
        • Polypropylene
        • Spandex.
    • 40. Video Clip 4 – 100% Cotton Clothing
    • 41. Video Clip 5 – Polyester/Cotton Clothing
    • 42. Arc Flash Rated PPE
      • Required minimum clothing:
        • Non-melting, untreated, natural fibre with a 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.
    • 43.
      • 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 Photo compliments of Salisbury Electrical Safety L.L.C.
    • 44. Video Clip 6 – FR Clothing
    • 45.
      • 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 Not all FR clothing is tested to ASTM F1506 Photo compliments of Salisbury Electrical Safety L.L.C.
    • 46. Topic 5 – Prevention
    • 47. 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.
    • 48.
      • Reduce the fault clearing time.
      • Reduce the short-circuit current.
      • Improve equipment maintenance.
      • Use flash resistant equipment.
      CONTROLLING ARC FLASH HAZARDS At the Source
    • 49.
      • 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
    • 50.
      • Energized electrical work permit
      • Barriers
      • Training and skills
      • Job briefings
      • PPE
      • Tools
      CONTROLLING ARC FLASH HAZARDS At the Worker Photo compliments of Salisbury Electrical Safety L.L.C.
    • 51.
      • Conduct a Flash Hazard Analysis to
        • determine the
          • Flash Protection Boundary
          • Incident Energy exposure
          • Type and arc rating of PPE
      Arc Flash Hazard Analysis If work must be done on or near energized electrical equipment, identify the potential for arc flash.
    • 52. Typical Protective Clothing Based on the 2004 edition of NFPA 70E 40 calories/cm ² Cotton underwear + FR shirt + FR pants + multi-layer flash suit 4 25 calories/cm ² Cotton underwear + FR shirt/pants/coveralls or Cotton underwear + 2 FR coveralls 3 8 calories/cm ² Cotton underwear + FR shirt + FR pants 2 4 calories/cm ² FR shirt + FR pants or FR coveralls 1 Not applicable Non-melting, flammable material with fabric weight of at least 4.5 oz/yd 0 Required Minimum Clothing Arc Rating Clothing Description Hazard/Risk Category
    • 53. Typical PPE Requirements Based on the 2004 edition of NFPA 70E    Ear Canal Inserts    Double-layer Switching Hood Face & Head Protection   Flash Suit Hood  Arc-rated Face Shield  4  3  2  1  0 Eye Protection Hazard/Risk Category
    • 54. 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.
    • 55. ARC FLASH HAZARDS It is ALWAYS preferable to work on de-energized equipment.