Arc Flash Hazards & Protection

  • View
    41

  • Download
    9

Embed Size (px)

DESCRIPTION

Arc Flash Hazards & Protection

Transcript

  • Arc Flash Hazards and

    Protection

    2013 Heath and Safety Conference

  • Arc Flash Hazards and Protection

    Presentation Summary Arc Flash Hazards Standards and Regulations Arc Flash Calculations Arc Flash Protection Arc-Rated PPE NB Power Update

  • Arc Flash Hazards

    What is an Arc Flash Hazard A dangerous condition associated with the possible release of

    energy caused by an electric arc. (CSA Z462-12)

  • Arc Flash Hazards

    What is an Electric Arc An electric arc is a short circuit through air

  • Arc Flash Hazards

    How can an Electric Arc occur? Dust, impurities, corrosion,

    condensation, animals Over-voltages across narrow gaps Failure of insulating materials Equipment failure Spark discharge from accidental

    touching, dropping tools with human interaction

  • Arc Flash Hazards

    What are some of the hazards associated with an arc flash incident? High Temperatures Molten Metal Pressure Waves Sound Waves Shrapnel Intense Light

    Pressure Waves

    Copper Vapor:Solid to VaporExpands by67,000 times

    Molten Metal

    Intense Light

    Hot Air-Rapid Expansion

    35,000 F20,000 C

    Shrapnel

    Sound Waves

  • Arc Flash Hazards

    What are some of the injuries that may result due to an arc flash incident? Burns Blindness Blast Injuries Shock Hearing Loss

  • Arc Flash Hazards

    What are the factors that contribute to the intensity of the energy released by an electric arc? What is the Available Fault Current? Is the electric arc occurring in an enclosure or in open air? How long will the worker be exposed to the flash? In other

    words, what is the time to trip? How far will the worker be from the electric arc?

    These are the major factors, but there are others such as arc length, voltage, number of phases, arc motion, grounded fault, etc

  • Arc Flash Hazards

    What is the term that describes the intensity of the energy released by an electric arc?

    INCIDENT ENERGY the amount of energy, impressed on a surface a certain distance from

    the source, generated during an electrical arc event. (CSA Z462-12)

    The unit of measure is sometimes in cal/cm2

  • Arc Flash Hazards

    Why now? Electricity has been around since the late 1800s why is this

    topic been so popular over the past few years?

  • Arc Flash Hazards

    Why now?INVENTION OF THE CAR - SEATBELT 1769 first self-propelled car which could attain speeds of up to 6 km/hr 1771 another steam-driven engine which ran so fast that it rammed into a wall, recording the

    worlds first accident 1807 design of the first internal combustion engine 1860 the first successful two-stroke gas driven engine 1885 the four stroke engine was devised 1908 The Ford Motor Company launched the Model T Ford 1955 Ford offered for the first time lap belts as an option 1956 Seat Belts offered in a safety package 1964 Most cars were sold with standard front seat belts 1968 Rear seat belts were made standard 1970 the state of Victoria, Australia, passed the first law worldwide making seat belt wearing

    compulsory for drivers and front-seat passengers but not rear. 1983 Seat Belts regulated in New Brunswick with exceptionsabout 200 years after the first car

  • Arc Flash Hazards

    Why now?Comparing the car to the invention of electricity and the seatbelt .to arc flash protectionSimilar to the regulations of the seat belt protecting against car accidents, it has taken us a few years to establish proper PPE against arc flash hazards

    1881 The first public electricity was delivered in 1881. 1882 New York first large scale distribution 1882 1884 The first turbine was in 1884. 1884 Electricity distributed in Saint John in 1884 1886 Electricity distributed in Moncton 1886 1887 Electricity distributed in Fredericton 1887 1920 NB Power formed in 1920it wasnt until 1984 when the hazards of arc flash was first documented.

  • Standard and Regulations

    History Summary 1969 research was conducted on burn victims and determine the level of heat

    energy (later to be termed IE) the onset of a second-degree burn (1.2 cal/cm2)

    1976 NFPA formed a committee at the request of OSHA to develop a electrical safety standard. The NFPA-70E was first published in 1979.

    1982 The first documented paper on arc flash hazards was published by Ralph Lee. The Other Electrical Hazards, Electric Arc Blast Burns

    1991 OSHA included the term Arc Flash as an additional hazard to the shock hazard of electricity.

    1992 At the request of ASTM F18 Committee Task Force on Electric Arc Test Method Development, Duke Power developed software to predict arc incident energy.

  • Standard and Regulations

    History Summary 1992 OSHA added the statement that the clothes worn by the worker must not

    increase the extent of the injury should the worker be exposed to arc flash on the job

    1995 Arc Flash Hazard was included in the 1995 edition of the NFPA 70E. This was the beginning of standards formally attempting to address this electrical hazard.

    1997-2000 Research and testing performed on protective clothing 2000 NFPA-70E updated based on this research and the HRC were introduced 2002 IEEE 1584 was published providing methods to complete calculations for

    predicting Incident Energy.

    2002 NEC acknowledges the arc flash hazard and introduced 110.16 Flash Protection. This article requires marking of certain electrical equipment to provide warning.

  • Standard and Regulations

    History Summary 2006 CEC was update to include awareness of Arc Flash Hazards. Rule 2-306

    requires a sticker to warn personnel of hazard of shock and now arc flash.

    2009 The 2009 edition of the National Electrical Safety Code (NESC) requires that, effective Jan. 1, 2009, electric utility systems that fall under this standard must perform an arc flash assessment.

    2009 CSA joins forces with NFPA-70E. CSA publishes Z462 Workplace Electrical Safety in January 2009 to establish the first electrcial safety program standard in Canada. (newest update in 2012)

    2010 - Since both the NFPA-70E and CSA Z472 exclude all installations under the exclusive control of an electric utility, CEA (Canadian Electrical Association) brought together utilities across Canada to develop and approve CN/ULC S801-10 Standard on Electric Utility Workplace Electrical Safety for Generation, Transmission, and Distribution.

  • Standard and Regulations

    Summary National Standards NFPA-70E is an American standard providing best practices

    for a safe electrical program for the industrial sector CSA Z462 is the Canadian version of the NFPA-70E ULC S801 is a Canadian standard providing best practices

    for a safe electrical program for utilities

    All of these standards outlines safe practices when working around electricity.

    All of these standards have a section that provides information about protecting workers against electrical arc hazards.

  • Standard and Regulations

    Regulations - United StatesUtilities - NESC: Effective January 1, 2009, the employer shall ensure that an assessment is performed to determine potential exposure to an electric arc for employees who work on or near energized parts or equipment. If the assessment determines a potential employee exposure greater than 2 cal/cm2 exists, the employer shall require employees to wear clothing or a clothing system that has an effective arc rating at least equal to the anticipated level of arc energy.Industry - OSHA: The employer shall ensure that each employee who is exposed to hazards from electric arcs wears clothing with an arc rating greater than or equal to the heat energy estimated under paragraph (l)(11)(ii) of this section.

  • Standard and Regulations

    Regulations New Brunswick

    OHSA Regulation 91-191 - 287.4(1) Where it is not practicable to de-energize electrical equipment before working on or near energized exposed parts of the equipment, an employee shall use rubber gloves, mats, shields and other protective equipment to ensure protection from electrical shocks and burns while performing the work.

  • Standard and Regulations

    In summary

    OHSA Regulation 91-191 states that an employer shall protect employees against electrical burns.

    and There are national standards that now provide direction and

    methods to protect workers against arc flash hazards

    QUESTION: Where do we start?

  • Arc Flash Calculations

    Arc Flash AssessmentsCSA Z462 - If energized electrical conductors or circuit parts operating at 50 V or more are not placed in an electrically safe work condition, other safety-related work practices shall be used to protect workers who might be exposed to the electrical hazards involved. Such work practices shall protect each worker from arc flash. Appropriate safety-related work practices shall be determined before any person is exposed to the electrical hazards involved by using both shock hazardanalysis and arc flash hazard analysis.

    ULC S801 - When workers are required to work on or near energized equipment above 240 V a.c. and sources greater than 125 kVA, an arc flash assessment should be performed in order to determine the potential incident energy of an arc flash for the specific equipment.

  • Arc Flash Calculations

    Arc Flash Assessments will determine:

    INCIDENT ENERGY The PPE that is required when working within the

    boundary. The distance a worker is required to be with no additional

    PPE if exposed to energized equipment (in regard to an arc flash)

  • Arc Flash Calculations