Transcript Document

Facility Management:
Maintenance Best
Practices
Steven Shapiro P.E. ATD
Mission Critical Practice Lead
Morrison Hershfield Mission Critical
Session Number: DCM 15.1
Session Title: Introduction to NFPA 70E and its Impact
on Your Facility
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Introduction to
®
NFPA 70E and its Impact on
Your Facility
This session will address NFPA 70E and its requirements for Arc
Flash labeling and calculations. It will also explain how mission
critical facility operations and reliability are affected.
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NFPA 70E® Standard for Electrical Safety in the
Workplace
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Introduction
History
Arc Flash
Mission Critical Environment
Summary
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Introduction
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NFPA 70E® - Introduction
Why NFPA 70E®
• A consensus standard that addresses employee
safety issues associated with installation of electrical
systems; to support the NFPA 70® National Electric
Code (NEC) and OSHA’s electrical safety standards
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NFPA 70E® - History 1979
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First published in 1979 70E® originally consisted only of Part I
Installation Safety Requirements
Development of the “complete” standard has been a process
(and remains so).
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NFPA 70E® - History 1995
The standard was expanded in subsequent editions to
include:
• Limits of Approach and establishment of an “arc” in 1995
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NFPA 70E® - History 2000
The standard was expanded in subsequent editions to include:
6th Edition in 2000 a new Part IV was finally added.
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Part I Installation Safety Requirements
Part II Safety-Related Work Practices
Part III Safety-Related Maintenance Requirements
Part IV Safety Requirements for Special Equipment
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NFPA 70E® - History 2004
7th Edition in 2004
• The Standard name was changed to the current name
• Parts were renamed as Chapters
• Major changes emphasized safe work practices
− Reorganized with Safety Related Work Practices up front
− New emphasis on live work as last alternative
− Added an energized electrical work permit and associated requirements
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NFPA 70E® - History 2004
7th Edition in 2004
• Usability of the standard was improved
− Added and modified definitions
• Part 4 was updated to correlate with NFPA 70 NEC 2002
• 70E® was reformatted to comply with NFPA 70 Style Manual
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NFPA 70E® - History 2009
2009 edition again yielded significant changes throughout
• Chapter 4 was deleted because it duplicated parts of NEC
• 70E now consisted of:
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Chapter 1 Safety-Related Work Practices
Chapter 2 Safety-Related Maintenance Requirements
Chapter 3 Safety Requirements for Special Equipment
Annexes A – O
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NFPA 70E® - History 2009
Other significant changes included:
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Protective clothing and equipment changes
Revisions to Annexes D, F and J
Addition of Annexes M, N and O
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NFPA 70E® - Today
NFPA 70E® 2012
• Currently consists of 3 chapters:
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Chapter 1 Safety-Related Work Practices
Chapter 2 Safety-Related Maintenance Requirements
Chapter 3 Safety Requirements for Special Equipment
Annexes A – P
• Significant changes have been made in Chapter 1
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NFPA 70E® - Today
NFPA 70E® 2012
• Other revisions expand or clarify NFPA 70E ® 2009
─ add new technical material
─ remove requirements related to safe installation
─ expand coverage of the concepts of hazard identification and risk
assessment
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NFPA 70E® - Today
NFPA Annexes
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Annex A Referenced Publications
Annex B Informational References
Annex C Limits of Approach
Annex D Incident Energy and Arc Flash Boundary Calculation Methods
Annex E Electrical Safety Program
Annex F Hazard Analysis, Risk Estimation and Risk Evaluation Procedure
Annex G Sample Lockout/Tagout Procedure
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NFPA 70E® - Today
NFPA Annexes (cont)
− Annex H Guidance on Selection of Protective Clothing and Other Personal
Protective Equipment
− Annex I Job Briefing and Planning Checklist
− Annex J Energized Electrical Work Permit
− Annex K General Categories of Electrical Hazards
− Annex L Typical Application of Safeguards in the Cell Line Work Zone
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NFPA 70E® - Today
NFPA Annexes (cont)
• Annex M Layering of Protective Clothing and Total System Arc Rating
• Annex N Example Industrial Procedures and Policies for Working Near
Overhead Electrical Lines and Equipment
• Annex O Safety Related Design Requirements
• Annex P Aligning Implementation of This Standard with Occupational Health &
Safety Management Standards
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NFPA 70E® - Electrical Safety Program
Summary of Article 110.3
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Documented (written) program based on electrical hazards
The electrical safety principles on which the program is based
Controls to measure and monitor the program
Electrical safety procedures for working within the limited approach boundary
(shock protection) and for working within the arc flash boundary
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NFPA 70E® - Electrical Safety Program
Summary of Article 110.3
− Hazard identification and a risk assessment procedure to be used prior to
working within limited approach boundary or within the arc flash boundary.
Identify process to be used by employees before work is started to identify hazards and assess
risks including mitigation strategies.
− A job briefing prior to starting each shift or each job that poses significantly
different hazards or if changes occur that might affect employee safety.
− A more detailed briefing for complicated or particularly hazardous jobs.
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NFPA 70E® - Electrical Safety Program
NFPA 70E ® and NEC state that facilities must provide:
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Safety program with defined responsibilities
Analysis for arc flash hazard degree
Training for workers
Personal protective equipment (clothing) for workers
Tools for safe work
Warning labels on equipment.
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Arc Flash Hazard Analysis
Arc Flash, What is it?
An arc flash results from an arcing fault, where the electric arcs and resulting radiation
and shrapnel can cause severe skin burns, hearing damage and eye injuries.
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Arc Flash Hazard Analysis
Why Now?
• Workers are injured and killed while working on energized equipment
• Working on energizes equipment is a necessity in
MISSON CRITICAL FACILITIES
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Arc Flash Hazard Analysis - Risk
Injuries
• Burns
• Respiratory system damage
• Hearing loss
• Skin Penetration injuries
• Eye and facial injuries
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Arc Flash Hazard Analysis - Risk
What Happens in an arc flash?
• The pressure of an arc blast is caused by the expansion of the metal as it vaporizes
and the heating of the air by the arc energy. This accounts for the expulsion of
molten metal up to 10 feet away.
• In addition, the sudden expansion of an arc blast creates loud sounds that can cause
hearing damage
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Arc Flash Hazard Analysis - Risk
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35,000 °F
Molten Metal
Pressure Waves
Sound Waves
Copper Vapor:
Solid to Vapor
Expands by
67,000 times
Shrapnel
Ionized Air-Rapid Expansion
Intense Radiation
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Arc Flash Hazard Analysis
Only qualified persons shall be permitted to work on energized equipment.
Qualified Person. One who has skills and knowledge related to the construction and operation of the
electrical equipment and installations and has received safety training to recognize and avoid the
hazards involved. NFPA 70E® .100)
Energized Electrical Conductors and Circuit Parts — Unsafe Work Condition. Only qualified
persons shall be permitted to work on electrical conductors or circuit parts that have not been put into an
electrically safe work condition. (NFPA 70AE ® 130.4)
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Arc Flash Hazard Analysis
A Flash Hazard Analysis shall be done to protect personnel from the possibility
of being injured by an arc flash
An arc flash hazard analysis shall determine:
− arc flash boundary
− incident energy at the working distance
− personal protective equipment that people within the arc flash boundary shall use.
(NFPA 70E® 130.5)
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Arc Flash Hazard Analysis
To calculate incident energy, technical data is collected such as equipment type,
voltage, ratings, impedance and other information to prepare an up to date electrical one
line diagram.
To provide accurate results, state-of- the-art software should be utilized to perform
the arc flash analysis to evaluate alternatives quickly and easily to establish an optimal
system design.
The arc flash hazard analysis shall be updated
• When a major modification or renovation takes place
• Periodically, not to exceed 5 years
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Arc Flash Hazard Analysis – Boundary Terms
Limited Approach - entered only by qualified
persons or unqualified persons that have been
advised and are escorted by a qualified person
Restricted Approach - entered only by qualified
persons required to use shock protection techniques
and PPE
Prohibited Approach - entered only by qualified
persons requiring same protection as if direct contact
with live part
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Arc Flash Hazard Analysis – Boundary Terms
Flash Protection Boundary -linear
distance to prevent any more than 2nd
degree burns from a potential arc-flash
(Typically 4 feet)
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Arc Flash Hazard Analysis
The arc flash hazard analysis shall take into consideration the design of the overcurrent
protective device and its opening time, including its condition of maintenance. (NFPA
70E 130.5)
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Arc Flash Hazard Analysis
There are two ways to complete an Arc Flash Hazard
Analysis
• Calculation
− Annex D NFPA 70E®
− IEEE 1584
• NFPA 70E® Tables
− 130.7(C)(15)(a),(b),(c)
− Per exception in 130.5
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Arc Flash Protection Calculations
• Collect the System Equipment Information
• Determine Power System Modes of Operations
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Normal Operation
Emergency Operation
Tie Switch Arrangements
Dual feeds
Open Transition, Closed Transition
Generators
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Arc Flash Protection Calculations
• Perform SC analysis to determine the Bolted Fault Currents
• Determine Arc Fault Currents
− Arcing Fault Current is a fault current flowing through an electrical
plasma arc.
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Arc Flash Protection Calculations
• Determine Arcing Duration
− Complete a Coordination Study
− From this study determine the arcing
duration
− Total clearing time of the fault will determine
the time factor in the incident energy
equation
− The fault clearing time is determined from
the Coordination Study’s Time Current
Curves.
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Arc Flash Protection Calculations
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Arc Flash Protection Calculations
• Determine Arcing Duration
− Determine Working Distances
− Determine Incident Energy
− Determine the Flash Protection Boundary
The incident energy for the flash-protection boundary must be set
at the minimum energy beyond which a second degree burn could
occur 1.2 cal/cm2
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Arc Flash Hazard Labeling
Electrical equipment such as switchboards, panelboards,… and are likely to
require examination, adjustment, servicing, or maintenance while energized,
shall be field marked with a label containing all the following information:
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Available incident energy and the corresponding working distance
Minimum arc rating of clothing
Required level of PPE
Highest Hazard/Risk Category (HRC) for the equipment
Nominal system voltage
Arc flash boundary
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WARNING
Arc Flash and Shock Hazard
Appropriate PPE Required
1 ft
Flash Hazard Boundary
0.60 cal/cm^2
Flash Hazard at 1 ft 6 in
Level 0
208 VAC
Nonmelting, Flammable Materials with
Weight >= 4.5 oz/sq yd
Shock Hazard when cover is removed
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Glove Class
3 ft 6 in
Limited Approach
Avoid Contact Restricted Approach
Avoid Contact Prohibited Approach
Bus: AHU-1-1 Prot: FBR AHU-1-1
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Mission Critical Environment
Preventive Maintenance Is a Must!
Maintaining all of your mission critical electrical
equipment is critical to:
• Ensuring worker safety
• Preventing unplanned downtime.
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Mission Critical Environment
Preventive Maintenance Is a Must!
NFPA 70E ® requires certain equipment and overcurrent protection
devices be maintained.
Such equipment would include:
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Substations and switchgear
assemblies,
Panelboards
Motor control centers,
Disconnect switches
Insulated conductors, grounds and
bus duct
PPE Equipment including electrical
gloves, hot sticks and flash suit
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Transfer switches and control equipment
Fuses and circuit breakers
Motors and generators
Equipment in hazardous locations
Batteries and battery rooms
Portable electric tools and equipment
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Mission Critical Environment
Single-Line Diagrams
NFPA 70E® requirements mandate accurate, up-to-date and legible single-line
diagrams. These documents are essential for documenting, troubleshooting,
and communicating information about your power systems. A comprehensive
site survey is essential to develop or update existing single-line diagrams or
complete electrical system drawings.
You can’t have an accurate Short Circuit, Coordination or Arc
Flash study without an updated One Line.
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Mission Critical Environment
Short Circuit, Coordination, Arc Flash Studies
Arc Flash calculations should be completed in conjunction with the
system short circuit study and coordination study
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Calculate momentary, interrupting and arcing current values
Compare available fault currents protective device ratings
Establish trip settings for all types of protective devices
This will minimize downtime for your entire power distribution system
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Summary
NFPA 70E®
Safety Standard that supports the NEC and OSHA
• Covers Safety Related Work Practices and Maintenance
Requirements.
• Electrical Safety Program
• Hazard Analysis
• Lock Out Tag Out – LOTO
• Energized work
• Arc Flash issues and PPE
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Questions?
Steven Shapiro, PE, ATD
Morrison Hershfield Mission Critical
[email protected]
914.420.3213
http://www.linkedin.com/in/stevenshapirope
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