Electrical StandDown Review of BNL ArcFlash Incident

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Electrical Stand-DownReview of BNL Arc-Flash
Incident Discussion of Arc-Flash Hazards
RelatingTo Switch Circuit Breaker Operations
John DiNicola LESC Chair
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Agenda

• Discuss BNL arc-flash incident
• Discuss other DOE arc-flash incidents
• Arc-flash hazards and mitigation
• Skill-of-the-craft and work planning
• Answer your questions
• Survey

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Review of Friday, April 14, 2006 Incident

• C-A engineer was operating a 480 volt, 400 amp
  fusible disconnect switch located in a 1,200 amp
  panel when the switch failed and an arc-flash
  occurred.
• The switch cover was closed and remained
  closed.
• The panel bulged and hot gasses escaped.
• Arc-flash ignited some paper located adjacent
  to the panel.

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Review of Friday, April 14, 2006 Incident

• Engineer received 1st degree burns on
  forearms, hands and face. He also received a
  small patch of 2nd degree burn on one forearm.
• Engineer went to the hospital and was released
  that afternoon.
• There is concern over the irritation of one
  eye, which will receive further evaluation.
• Person was wearing cotton undergarments,
  short-sleeve cotton shirt , blue jeans, but no
  eye protection.
• Person had valid Electrical Safety I and C-A
  Electrical Training.

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Review of Friday, April 14, 2006 Incident
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Review of Friday, April 14, 2006 Incident
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ANL Arc-Flash In 277 Volt Switch 10/23/2005

• Scientist operated an outdoor 277Volt switch to
  turn on lights in gas yard.
• Switch failed, hot gasses escaped, caused 2nd
  degree burn on hand.

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SLAC Arc-Flash Incident
Worker received 3rd degree burns
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ORNL Arc-Flash Incident 3/26/2006

• Worker (contractor electrician) was installing
  ground connection to cable tray which has
  energized 480 Volt cable in it.
• Drill penetrated tray and cable insulation
  causing a short and resulting arc-flash.
• Breaker tripped to end the event
• Worker received mild burn on forearm and hand.

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Arc/Blast Caused Burns

• First Degree burns affect only the surface of the
  skin. The burned area is red and tender, much
  like a mild sunburn.Second Degree burns are
  characterized by blistering of the skin, either
  early or late. The complete thickness of the
  skin is not destroyed. This is the most painful
  type of burn.Third Degree burns are
  characterized by complete destruction of the skin
  with charring and cooking of the deeper tissues.
  These are the most serious types of burns as they
  produce deeper wounds. They are not as painful
  because the sensory nerve endings have been
  destroyed.
• Fourth Degree burns  goes through all the layers
  of the skin and down into the muscle and the
  bone. It looks like a third degree burn and does
  great harm to the body structure. Since the
  nerves are burnt there is little pain in this
  burn.

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What is Proper PPE Audience Questions

• What is the proper PPE for operating a 480 Volt
  switch with the cover closed?
• Would this have been adequate PPE? What does the
  code (NFPA 70E) say the PPE should do?

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Answers to Audience questions

• Operation of any switch or CB lt600Volts requires
• Cotton undergarments
• Long sleeve non-melting fiber or untreated
  natural-fiber shirt and pants (untreated cotton,
  wool, rayon, or silk)
• Eye protection (safety glasses or goggles)
• PPE is designed to limit the burn to onset of
  second degree burn (curable)
• A bad sun burn

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Skill of the Craft

• Is work planning required for skill of the craft
  work?

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Skill of the Craft Work Planning

• Is work planning required for skill of the craft
  work?
• STOP! Review the operation
• Determine the hazards
• Determine the hazard mitigation (PPE, techniques,
  etc.)

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Review the Operation Read the Signs
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Review the Operation Read the Signs
Note Specific Personal Protective Equipment and
approach boundaries are specified Example is
provided by a vendor. At BNL, dimensions and
Personal Protective Equipment requirements are
evaluated on a case-by-case basis.
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Review the Operation Read the Signs
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Determine the Hazards

• Exposed bus - shock hazard?
• Am I in the arc-flash boundary?
• What other hazards surround me?
• Trip
• Height
• Obstructions
• Sharp Edges

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Arc-Flash and Blast Hazard

• If equipment failure occurs, there is a potential
  for an arc flash.
• Under normal operation of circuit breakers and
  disconnect switches the risk of arc flash is
  extremely low. However, an arc flash with
  protective covers off is a serious,
  life-threatening occurrence.

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Arc-Flash and Blast Hazards

• An electric arc produces heat at 15,000oC
  (35,000oF), which results in extremely intense
  heat exposure to a persons body and clothing.

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Determine the Hazards/Risks
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Determine the Hazards/Risks
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Hazards of Switch/CB Operation

• 240 Volt and below Panelboards
• Operation of switch or circuit breaker w/covers
  ON Hazard/Risk Cat 0
• Operation of switch or circuit breaker w/covers
  OFF Hazard/Risk Cat 1
• gt 240V to 600 Volt Panelboards
• Operation of switch or circuit breaker w/covers
  ON Hazard/Risk Cat 0
• Operation of switch or circuit breaker w/covers
  OFF Hazard/Risk Cat 1

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Determine the Hazard Mitigation
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Clothing for the Hazard/Risk Mitigation

• Hazard/Risk Categories
• 0 Non-melting or untreated natural fiber
  clothing, long sleeves and pants
• 1 Fire Rated (FR) clothing (heavy duty jeans
  permissible)
• 2 Fire Rated (FR) clothing
• 2 Like 2 but with Flash hood
• 3 and up Flash suits, multiple layers FR

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Other PPE for the Hazard/Risk Mitigation

• Eye protection always required
• Maybe required depending on the task
• Hard hats
• Face shields
• Hearing protection
• Gloves leather and/or voltage rated
• These are items that should be reviewed during
  your work planning (formal or skill of the craft)

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Minimum Personal Protective Equipment

• The minimum PPE for operation of circuit breakers
  and disconnect switches (cover ON) operating at
  less than 600 Volts with covers on, is
• Safety Glasses
• Non-melting or untreated natural fiber clothing
  such as untreated cotton, wool, rayon, or silk.
• Long-sleeve shirt
• Pants
• Whats wrong in this picture?

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Safety Glasses Always Required!
Remember in all cases these operations still
require the use of safety glasses!
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Proper Operation to Reduce Risk

• When pulling the handle on a disconnect switch or
  operating a circuit breaker, always consider the
  possibility of an arc explosion. Stand to the
  side and turn your face away when throwing the
  switch, if possible.

WRONG Never stand in front of, or
directly face the switch
CORRECT Stand to the side of the
switch and face away.
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Who is Responsible for Safety?

• WE ARE!!!!!!!!!!!!!
• We look out for ourselves
• We look out for others
• We can STOP WORK!!! We are obligated to do so!

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Good Housekeeping

• Three recent electrical incidents resulted in the
  ignition of combustible materials located near
  the equipment.
• The material did not need to be there!

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Where to Find this Presentation?

• http//www.bnl.gov/esh/esc/
• Electrical Safety Committee
• Web Page

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Please Help Us

• A short anonymous survey is being handed out to
  help us evaluate the effectiveness of past
  training
• Side 1 For workers who have taken Electrical
  Safety I training. ( The longer survey)
• Side 2 All others
• Survey is simple Y or N with possibility for free
  form comments at the end. Please hand in as you
  leave!