Arc Flash Analysis Oct 11 2010.pdf

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Attached to: Arc Flash Analysis Federal contract opportunity
Solicitation number: 12505B21R0014
Issued by: Department of Agriculture Agricultural Research Service Field Research Implementation and Information Delivery Midwest Area

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United States Department of Agriculture Agricultural Research Service

Final Submittal Task Order No. AG-5114-D-09-0098

AG-5114-D-09-0096

Contract No. AG-3K15-53-3K15-4-1500 Order Date. 9/26/09 BE Project No. 0413-08-19

0413-08-20

Arc Flash Analysis and Labeling:

480V & 120V NCAH Ames, IA

BY: ARCHITECT CONSULTANT

Bailey Edward architecture KJWW Engineers

116 N Pelham 2882 106th Street Rhinelander, WI 54501 Des Moines, IA 50322

715-362-3662 515-344-4302

DATE: October 11, 2010

Table of Contents

1. EXECUTIVE SUMMARY

A. INTRODUCTION

B. OBJECTIVES

C. RESULTS, DEFICIENCIES AND RECOMMENDATIONS

D. METHODOLOGY

E. IEEE 1584 CALCULATION METHODOLOGY

2. ARC FLASH HAZARD RESULTS

A. ARC FLASH HAZARD CATEGORY TABLE

B. ARC FLASH HAZARD LABELING

APPENDIX A: PTW ELECTRICAL COMPONENT INPUT DATA REPORTS

North Campus Input Data Report South Campus Input Data Report

APPENDIX B: PTW SHORT CIRCUIT ANALYSIS DATA REPORT

North Campus Short Circuit Analysis Report South Campus Short Circuit Analysis Report

APPENDIX C: ARC FLASH HAZARD TABLE

North Campus Arc Flash Hazard Table South Campus Arc Flash Hazard Table

APPENDIX D: PTW ONE-LINE DIAGRAMS

North Campus:

1-7_153 UTL&GEN

2-7_154T1&T2 3-7_154T3&T4

4-7_E-MCC-1&2

5-7_153T5&T6 6-7_154T7&T8 7-7_156T9&T10 9_E1.03A 9-E1.01-A

BLDG 5

BLDG 10

BLDG 530

NORTH LOOP 4160

South Campus:

11-46

BLDG A1-A9

BLDG C1-C5

EMCC

MDP-1

MDP-2

MDP-3

PANEL CDP

USDA SOUTH LOOP

APPENDIX E: Label Printing Spreadsheet

North Campus Danger Labels Spreadsheet North Campus Warning Labels Spreadsheet South Campus Danger Labels Spreadsheet South Campus Warning Labels Spreadsheet

APPENDIX F: Sample Labels

Arc Flash Hazard Analysis & Labeling: 4801V & 120V, Ames, IA

October 11, 2010

1. EXECUTIVE SUMMARY

A. INTRODUCTION

KJWW Engineering was contracted to provide an arc flash hazard analysis for the USDA

Campus located in Ames, Iowa. The analysis was done during the time period of

December 2009 – June 2010 and reflects the conditions of the electrical power system at the time of the report. Input data used in the analysis was acquired by KJWW

Engineering and provided by others. Data was obtained from existing drawings, shop drawings, site visits, manufacturer’s published information, and the electrical contractor.

B. OBJECTIVES

Provide an arc-flash hazard analysis to determine the incident energy levels at specified working distance from selected electrical equipment, which can be used to select appropriate Personal Protective Equipment (PPE) to be used when working within the flash protection boundary. The flash protection boundary is the area within which a worker without proper protection would expect to receive second degree burns at a minimum. The potential for harm increases as the arc flash incident level increases.

This report does not purport to provide short circuit analysis or protective device coordination.

C. RESULTS, DEFICIENCIES AND RECOMMENDATIONS

1) Arc-flash Hazard Analysis Results and Deficiencies:

The results of the arc-flash hazard analysis show that the electrical equipment evaluated have incident energy levels that do not exceed 40 cal/cm2 with the following exceptions:

North Campus:

a) ALLIENT SERVICE FEED DANGEROUS

b) E-MCC-15 DANGEROUS

c) E-MCC-16 DANGEROUS

d) E-MCC-3 DANGEROUS

e) E-MCC-4 DANGEROUS

f) E-SWGR-1(A) DANGEROUS

g) E-SWGR-1(B) DANGEROUS

h) E-SWGR-11 BUS A DANGEROUS

i) E-SWGR-11 BUS B DANGEROUS

j) FP-1 DANGEROUS

k) MDP DANGEROUS

l) XF2-154T3 SEC DANGEROUS

m) XF2-154T4 SEC DANGEROUS

n) XF2-154T5(E-MCC-3) SEC DANGEROUS

o) XF2-154T6(E-MCC-4) SEC DANGEROUS

p) XF2-154T7 SEC DANGEROUS

q) XF2-154T8 SEC DANGEROUS

r) XF2-156T10(E-MCC-16) SEC DANGEROUS

s) XF2-156T9 SEC DANGEROUS

South Campus:

a) ATS-1 DANGEROUS

b) EMCC DANGEROUS

c) MDP(C8) DANGEROUS

d) MDP-B1 DANGEROUS

e) MDP-B2 DANGEROUS

f) MDS-C2-A DANGEROUS

g) MDS-C3 DANGEROUS

h) MDS-C4 DANGEROUS

i) XF2-T1(B1,B2) SEC DANGEROUS

j) XF2-T10(C2) Sec DANGEROUS

k) XF2-T11(C3) Sec DANGEROUS

l) XF2-T12(C4) SEC DANGEROUS

m) XF2-T8(C8) SEC DANGEROUS

NFPA 70E does not explicitly prohibit work at locations with incident energy levels above

40 cal/cm2 (Class 4). The potential for non-burn injuries from the arc blast (internal injuries, hearing damage, etc.) are a significant hazard at high-energy locations. KJWW

Engineering does not recommend work on energized electrical equipment in locations with incident energy levels above 40 cal/cm2. KJWW Engineering recommends that work in these locations be done when the equipment is de-energized and placed in an electrically safe work condition.

Other noted electrical deficiencies:

During the power system study items were noted that may be code compliance issues, equipment is missing proper labels and potential maintenance issues. These items were beyond the scope of KJWW Engineers work but were mentioned to bring them to the attention of the facility staff.

The following items or deficiencies were noted:

a) 1 engraved label needed on the circuit breaker for the 75 KVAR capacitor bank in MDP1 in building 400.

b) 1 engraved label needed on the circuit breaker for the 75 KVAR capacitor bank in MDP2 in building 400.

c) 2 blank breaker filler plates needed in panel OP12C in building 400 (Type:

Square D, QO, Load Center).

d) 1 blank breaker filler plate needed in panel LP-3 in building 400 (Type:

Westinghouse, DM).

e) 2 blank breaker filler plates needed in panel MDP outside building A2 (Type:

Square D).

2) Recommendations:

The arc-flash hazard labels should be placed on the electrical equipment and the analysis should be incorporated into the facilities operating and maintenance procedures.

Assumptions:

The following assumptions were made in preparing the power system study, and result in worst-case conservative results:

a) The double-ended equipment was modeled with the tie-breaker open and the main breakers separately connected to their respective utility sources.

b) For fault calculations, system voltage was modeled at the no load value with transformer taps modeled.

c) All motors were assumed to be running.

d) Motors were modeled as shown on the Power Tools for Windows (PTW) study one line diagrams and in the PTW INPUT DATA REPORT.

e) Motors were modeled as standard PTW induction motor components.

D. METHODOLOGY

The PTW Arc Flash software module was used to calculate the arc flash incident energy and flash boundary at each device under study. The Arc Flash Hazard Analysis software module uses equations based on both NFPA 70E and IEEE 1584. The software calculates the arcing fault current at each bus in the model based on the available fault current determined during the short-circuit analysis and the equations in IEEE 1584. The arc duration is determined from the calculated arc fault current and the time-current characteristics of the upstream protective device. The arc fault current and fault duration are inputs into the IEEE 1584 equations to calculate the incident energy and flash-protection boundary. For low voltage (<1000 volts) buses, a second arcing fault current value is calculated to be 85% of the arcing fault value originally calculated and a second device operating time is determined, per IEEE 1584. The incident energy and protection boundary are calculated using both values and the worst case result is report in the summary.

The calculated incident energy levels are based on the “working distance”, defined as the distance from the fault to the worker’s head and torso. IEEE 1584 recommendations of

36 inches for medium voltage equipment, 24 inches for low-voltage switchgear and 18 inches for panelboards and motor control centers were assumed. The flash protection boundary distance is calculated as the distance from the equipment where the incident energy equals 1.2 cal/cm2. The 1.2 cal/cm2 is the accepted energy level that causes the onset of second degree burns on bare skin. PPE is required for working inside the flash protection boundary.

Induction motor contribution to the fault current was considered in the analysis.

Contribution from motors of 50 horsepower and above was assumed to be zero after 5 cycles, if the protective device had not already opened.

The values shown in the table for low-voltage switchboards, panelboards and motor control centers assumes that the fault is cleared by the upstream protective device. A fault on the incoming line terminals could propagate throughout the enclosure, since they do not have internal barriers or compartments. This assumption creates conservative calculation results.

The maximum trip delay time was set at 2 seconds in this study. That a worker exposed to an arcing fault will quickly move away from the source of the arc if physically possible, is recognized in IEEE 1584 Annex B.1.2 in the statement “… two seconds is a reasonable maximum time…”.

Buses with incident energy greater the 40 cal/cm2 are classified hazard risk category

“DANGEROUS” and NFPA 70E does not define protective clothing classes that excesses

Category 4. KJWW Engineering does not recommend energized work at any location where the arc-flash incident energy exceeds 40 cal/cm2 .

The results are based on the assumption that protective devices are in working order and will operate within their specified tolerances to clear faults from the system.

The results in this arc-flash hazard study are based solely on the IEEE 1584 calculation procedures.

E. IEEE 1584 CALCULATION METHODOLOGY

The IEEE Standard 1584-2002 IEEE Guide for Performing Arc-Flash Hazard Calculations presents a comprehensive methodology for arc-flash hazards. This standard based on extensive testing carried out on low-voltage and medium voltage systems (up to 15kV).

IEEE 1584 is applicable only to three-phase arcing faults and it does not consider the effects of arc blast or other by-products and arcing fault (sound level, ionized gases, molten metal, toxic vapors, etc.)

2. ARC FLASH HAZARD RESULTS

The arc-flash hazard analysis and recommended PPE levels are not substitutes for safe work practices. Protection from arc flash can be provided by working only on circuits or equipment that has been place in an electrically safe work condition, including lock-out/tag-out, voltage testing and grounding. NFPA 70E 130.7(A) fine print note No. 1 states that burn injuries can occur even when adequate PPE is employed, and recommended PPE may provide little or no protection against arc blast and its effects.

A. ARC FLASH HAZARD CATEGORY TABLE

TABLE HEADING DEFINITIONS

Hazard Risk Category – Category 0, 1, 2, 3, 4 or Dangerous!

Warning Label Text – Heading of WARNING or DANGER

Incident Energy (cal/cm2) – the amount of energy impressed on a surface, a certain distance from the source, generated during an electrical arc event.

Arc Flash Protection Boundary - distance from the equipment where the incident energy equals 1.2 cal/cm2. PPE is required for working inside the flash protection boundary

Shock Hazard - Voltage with covers and doors open.

Limited Approach Boundary - a boundary around exposed live parts that may not be crossed by an “unqualified” person unless accompanied by “qualified” persons.

Restricted Approach Boundary - is the area near the exposed live parts that may be crossed only by “qualified” persons using appropriate shock prevention techniques and equipment.

Prohibited Approach Boundary - is the area near exposed live parts that may be crossed only by “qualified” persons using the same protection as if direct contact with live parts is planned.

ARC FLASH HAZARD CATEGORY TABLE

Hazard

Risk