Fire Retardant (FR) Clothing NESC Compliance

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Fire Retardant (FR)Clothing NESC Compliance

• Brent McKinney, P.E.
• Manager Electric TD
• APPA Principal Member
• NESC Subcommittee 8

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Disclaimer

• Compliance with NESC, NEC, OSHA and / or all
  applicable codes and rules are the responsibility
  of each individual utility. This presentation
  merely provides background information so that
  each utility can make its own decision concerning
  compliance.
• Nothing contained in this presentation is
  intended to constitute legal advice. We
  recommend that you consult with qualified legal
  counsel regarding compliance with all codes,
  laws, and regulations.

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Outline

• Consensus Standard
• NESC, NEC Scope
• NESC Subcommittee Structure
• NESC Subcommittee 8 FR Clothing History
• NESC FR Clothing Compliance 2009
• NESC FR Clothing Compliance 2012
• Questions

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• Consensus Standard Standard which is generally
  agreed upon by all entities affected.
• NESC NEC are Consensus Standards
• NESC IEEE
• NEC NFPA

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• NEC is primarily for non-utility companies past
  the meter.
• NEC Utility Exemption See NFPA 70E 90.1.B.5

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• NFPA is proposing to remove utility exemption for
  NEC.

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• NESC is minimum safety consensus standard for
  electric utilities.
• States, cities may adopt.
• Accepted as national safety consensus standard.

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• NESC is governed by 7 subcommittees
• 1.Purpose, Scope, Application, Definitions and
  References
• 2. Grounding Methods
• 3. Electric Supply Stations
• 4. Overhead Lines - Clearances
• 5. Overhead Lines Strength and Loading
• 6. None
• 7. Underground Lines
• 8. Work Rules

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• NESC subcommittees made up of utility
  representatives, consultants, IBEW, NSPE, TelCom
  industry and others.
• No one group can have more than 33
  representation.
• NESC Subcommittee 8 responsible for worker safety
  rules.
• Responsible for FR clothing rules.

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FR Clothing History

• Change Proposal (CP) submitted to SC8 by IBEW in
  2005
• OSHA told committee it needed consensus standard
  for new 1910.269 Rule
• OSHA would use NEC 70-E if NESC did not pass FR
  clothing rule.

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FR Clothing History contd

• Nearly all SC8 members now under OSHA
• SC8 companies felt FR clothing rule must be
  passed
• Significant disagreement among committee
• Working group developed to write FR rule and
  bring back to subcommittee

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FR Clothing History contd

• EEI, NRECA, APPA, OSHA, IBEW representatives on
  committee 8-10 people
• Committee met three times

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Issues

• APPA and NRECA insisted tables be provided
  instead of requiring Arc hazard analysis.
• Little and poor data on Arc hazard incidents and
  tests.
• OSHA used ArcPro 2.0 to determine arcs.

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Issues contd

• What arc distance should be used?
• Would regular jeans be allowed?
• Would the heat stress of the clothes be more of a
  problem than the arc hazards?
• Who should pay for the clothes?
• When should the rule begin?

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Issues contd

• What do we do for arcs under 1,000V?
• OSHA must accept.

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• Finally consensus reached, no one completely
  happy.
• APPA votes to reject rule.

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Rules

• 1. Effective as of 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 (see Neal, Bingham, and Doughty
  B59), the employer shall require employees to
  wear clothing or a clothing system that has an
  effective arc rating not less than the
  anticipated level of arc energy

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Rules contd

• 2. When exposed to an electric arc or flame,
  clothing made from the following materials shall
  not be worn acetate, nylon, polyester, or
  polypropylene. The effective arc rating of
  clothing or a clothing system to be worn at
  voltages 1000 V and above shall be determined
  using Tables 410-1 and 410-2 or performing an arc
  hazard analysis. When an arc hazard analysis is
  performed, it shall include a calculation of the
  estimated arc energy based on the available fault
  current, the duration of the arc (cycles), and
  the distance from the arc to the employee.

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Rules contd

• 3. EXCEPTION 1 If the clothing required by this
  rule has the potential to create additional and
  greater hazards than the possible exposure to the
  heat energy of the electric arc, then clothing
  with an arc rating or arc thermal performance
  value (ATPV) less than that required by the rule
  can be worn.
• EXCEPTION 2 For secondary systems below 1000 V,
  applicable work rules required by this part and
  engineering controls shall be utilized to limit
  exposure. In lieu of performing an arc hazard
  analysis, clothing or a clothing system with a
  minimum effective arc rating of 4 cal/cm2 shall
  be required to limit the likelihood of ignition.

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Rules contd

• 4. NOTE 1 A clothing system (multiple layers)
  that includes an outer layer of flame resistant
  material and an inner layer of non-flame
  resistant material has been shown to block more
  heat than a single layer. The effect of the
  combination of these multiple layers can be
  referred to as the effective arc rating.
• NOTE 2 It is recognized that arc energy levels
  can be excessive with secondary systems.
  Applicable work rules required by this part and
  engineering controls should be utilized.

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Rules contd

• 5. Employers shall utilize positive procedures to
  secure compliance with these rules. Cases may
  arise, however, where the strict enforcement of
  some particular rule could seriously impede the
  safe progress of the work at hand in such cases
  the employee in charge of the work to be done
  should make such temporary modification of the
  rules as will accomplish the work without
  increasing the hazard.
• If a difference of opinion arises with respect
  to the application of these rules, the decision
  of the employer or the employer's authorized
  agent shall be final. This decision shall not
  result in any employee performing work in a
  manner that is unduly hazardous to the employee
  or to the employee's fellow workers.

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6.
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• NESC 2012 CPs initial meeting
• Low voltage working group developed update FR
  clothing rule including new table under 1000 Volts

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• Table 410- 23 Live-line tool work clothing and
  clothing systemsvoltage, fault current, and
  maximum clearing time for voltages 46.1 to 800 kV
  1 AC
• (See Rule 410A3)
• Supporting Comments
• Currently, Rule 410A3 requires the use of
  clothing or clothing systems with a minimum
  effective arc rating of 4 cal /cm2 for voltages
  less than 1000 V, in lieu of performing an arc
  hazard analysis.
• Subcommittee 8 established a Low Voltage Arc
  Flash Work Group (WG) to evaluate the necessary
  minimum clothing or clothing system requirements
  for employees working on energized lines and
  parts operating at voltages less than 1000V and
  to develop a Change Proposal, if needed, to
  revise Rule 410A3.

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• The WGs initial evaluations concluded that aside
  from anecdotal evidence no technically
  substantiated data based upon specific industry
  testing existed to justify the creation of a new
  table, similar to existing Tables 410-1 and
  410-2, for voltages less than 1000V. However,
  during the spring and summer of 2008, the Pacific
  Gas and Electric Company initiated and completed
  a series of scientific tests to determine the arc
  flash characteristics of 480V self-contained
  metering equipment by creating fault conditions
  at various kA levels (sans fault protection
  devices).
• Based on PGEs test results and the application
  of an accepted industry standard (IEEE
  1584-2002), the WG submitted a report to
  Subcommittee 8 which included revisions to Rule
  410A3 and a new Table (410-1).

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• The revisions to Rule 410A3 seek to clarify the
  difference between performing an assessment and
  an arc hazard analysis, the conditions under
  which an arc hazard analysis is to be performed,
  and the employers requirements for determining
  the necessary clothing or clothing systems.
• New Table 410-1 Clothing and Clothing Systems
  (per cm2) for voltages 50 to 1000 V (AC) and
  existing Tables (renumbered to 410-2 and 410-3)
  are cited in new text 410A3a to offer employers
  the option of using tabulated values for clothing
  and clothing systems in lieu of performing an arc
  hazard analysis.

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• The supplemental notes to new Table 410 -1
  identify certain parameters that vary from the
  pre-existing tables (new 410-2 and 410-3). One
  such difference is the use of an 18 in. worker
  separation distance. On this particular topic, it
  should be noted that the supporting test results
  are based on the application of IEEE Std. 1584
  test methodologies and typical working distances
  for low voltage motor control centers and panel
  boards (Table 3 p. 9). It seemed prudent to the
  workgroup to apply the 18 in. working distances
  to determine the cal/cm2 values for other listed
  equipment and for other voltage ranges, since
  Section 4.8 (IEEE 1584) states that arc flash
  protection is based on the incident energy level
  on the workers face and body, not the incident
  energy on the hands and arms.
• The supplemental notes to new Table 410-1 also
  include statements identical to those in
  pre-existing tables (renumbered 410-2 and 410-3)
  that allow the user to apply different methods of
  calculating arc exposure values.

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Revisions to Rule 410A3

• Effective as of January 1, 2009, tThe employer
  shall ensure that an assessment is performed to
  determine potential exposure to an electric arc
  for employees who work on or near energized
  lines, parts or equipment.
• If the assessment determines a potential
  employee exposure greater than 2 cal/cm2 exists
  (see Neal, Bingham, and Doughty B59), the
  employer shall
• a. Perform a detailed arc hazard analysis, or
  use Table 410-1, Table 410-2, or Table 410-3 to
  determine the effective arc rating of clothing or
  clothing system to be worn by employees working
  on or near energized lines, parts, or equipment
  at voltages 50 800,000 volts.
• When an The arc hazard analysis is performed, it
  shall include a calculation of the estimated arc
  energy based on the available fault current, the
  duration of the arc (cycles), and the distance
  from the arc to the employee.

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• b. Require employees to wear clothing or a
  clothing system that haswith an effective arc
  rating not less than the anticipated level of arc
  energy.
• When exposed to an electric arc or flame,
  clothing or a clothing system made from the
  following materials, unless flame resistant,
  shall not be worn acetate, nylon, polyester, or
  polypropylene.

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• EXCEPTION 1 If the clothing or clothing system
  required by this rule has the potential to create
  additional andor greater hazards than the
  possible exposure to the heat energy of the
  electric arc, then clothing with an arc rating or
  arc thermal performance value (ATPV) less than
  that required by theis rule canmay be worn.

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• NOTE 1 Assessments performed to determine
  potential exposure to an electric arc consider
  the affected employees assigned tasks and/or
  work activities.
• NOTE 12 A clothing system (multiple layers) that
  includes an outer layer of flame resistant
  material and an inner layer of non-flame
  resistant natural fiber material has been shown
  to block more heat than a single layer. The
  effect of the combination of these multiple
  layers canmay be referred to as the effective arc
  rating.
• NOTE 23 It is recognized that arc energy levels
  can be excessive with secondary systems.
  Applicable work rules required by this part and
  engineering controls should be utilized.
• Engineering controls can be utilized to reduce
  arc energy levels and work practices can be
  utilized to reduce exposure levels.

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New Table 410-1

• Table 410-1 Clothing and Clothing Systems (per
  cm2) for voltages 50 to 1000 V (AC)
• (See Rule 410A3.)
• Nominal Voltage Range and Calories/Cm 2
• Equipment Type 50 250V 251
  500V 501 1000 V
• Self-contained Metering
• Pad-mounted transformers/
• Panels cabinets 42 204
  308
• CT Meters and
• control wiring 42 45
  68
• Metal-clad Switchgear /
• Motor Control Centers 83 406
  608
• Subsurface/ Pedestal-
• mounted Equipment 42
  87 12 8
• Open Air (includes lines) 42
  42 68

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• Notes
• 1. This table is based on maximum fault current
  of 51kA.
• Calculations are based on an 18-in separation
  distance from the arc to the employee. See IEEE
  1584-2002.
• Other methods are available to estimate arc
  exposure values and may yield slightly different
  but equally acceptable results.
• The use of the table in the selection of
  clothing is intended to reduce the amount or
  degree of injury but may not prevent all burns.
• Industry testing by two separate major utilities
  has demonstrated that voltages 50 - 240V will not
  sustain arcs for more than 0.5 cycles thereby
  limiting exposure to less than 4 calories/cm2.
• Value based on industry test results and IEEE
  Std. 1584-2002 formula for Motor Control Centers.
  (Gap 1 in.) (Xd 1.641) (18 in. distance) 51kA
  (Based on a 208V, 1000kVA, 5.3 Z, served from a
  500mVA system) Maximum duration (from tests) is
  10 cycles 46.5 cal/s/cm2 0.167 sec 7.8
  cal/cm2
• 4. Industry testing on 480V equipment indicates
  exposures for self-contained meters do not exceed
  20 calories/cm2.

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• Industry testing on 480V equipment indicates
  exposures for CT meters and control wiring does
  not exceed 4 calories/cm2.
• Value based on industry test results and IEEE
  Std. 1584-2002 formula for Motor Control Centers.
  (Gap 1 and Xd 1.641, 18 inch distance)
  12.7kA at 480 V (worst case energy value from
  testing). Maximum duration from tests is 85
  cycles 26.2 cal/s/cm2 1.42 sec 37 cal/cm2
• Incident analysis on this equipment indicates
  exposures do not exceed 8 calories/cm2.
• 8. Incident analysis and industry testing
  indicates that applying a 150 multiplier to the
  480V exposure values provides a conservative
  value for equipment and open air lines operating
  at 501 1000V.

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Questions?Contact Information

• Brent McKinney
• Manager, Electric TD
• City Utilities of Springfield
• Phone [phone]
• Email brent.mckinney_at_cityutilities.net
• Nathan Mitchell
• Director of Engineering Services
• American Public Power Association
• Phone [phone]
• Email nmitchell_at_appanet.org

Mike Hyland VP of Engineering Services American
Public Power Association Phone
202/467-2986 Email mhyland_at_appanet.org
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Additional Information Available at

• EO Conference March 22-25, 2009 Austin, Texas
• The 14th Edition of the APPA Safety Manual
  Available Now at APPAnet.org