Impact of Arc Flash Test Exposure Conditions on PPE Arc Rating:

Update for ASTM F18.65San Antonio, Texas

October 13, 2008Mike Lang Tom Neal

2008 IEEE IAS Electrical Safety Workshop

2

WHAT DO I MEAN BYDIFFERENT TEST CONFIGURATIONS?

ASTM F1959 and F2178 Single Phase Arc Test Methods for Fabrics and Face ProtectionDoughty/Neal IEEE Arc-In-a-Box 3-Phase Vertical Conductor Test ConfigurationFerraz Shawmut Arc-In-a-Box 3-Phase Test Configuration with Vertical Conductors Terminated into an Insulating BarrierFerraz Shawmut Arc-In-a-Box 3-Phase Test Configuration with Horizontal Electrodes

3

Open Arc Configuration, i.e. No Enclosure8 kA, 3 kV, Phase to Ground5 to 130 Cycles DurationVertical Stainless Steel Electrodes with 12” GapHigher Radiant Energy than Convective EnergyIncident Energy from 1 to 120 cal/cm²

ASTM F1958, F1959 & F2178 Test Methods

4

ASTM Arc Test Method Configuration

All Arc Test Methods Use the Same Arc Geometry

F1959 Fabric Arc RatingF1958 Clothing Ignition F2178 Face Protection

5

Arc Test MethodFor Determining the Arc Rating of Face Protective Products

Utilizes Eye, Mouth & Chin Sensors

>100 cal/cm² Arc Rated Hood

ASTM F2178ASTM F2178

6

Doughty/Neal IEEE Arc-In-a-Box Test Configuration

600V 3-Phase 25 to 50kA1.25 inch GapVertical Electrodes w/o Barrier Copper Electrodes, 0.75” Diameter 7 cycles Arc DurationNo fabric or face shield arc rating tests

7

IEEE ARC-IN-A-BOX TEST SETUP

8

9

IEEE/Ferraz ShawmutArc-In-a-Box Test Configurations

480V 3-Phase25 to 50kA 1.25 inches GapVertical Electrodes Terminated with Barrier or Horizontal Electrodes Copper Electrodes, 0.75” Diameter 2 to 20 cycles Arc DurationFabric and Face Shield Testing

Ferraz Shawmut Horizontal ConfigurationFerraz Shawmut Horizontal Configuration

44.6kA, 6 cycle, 600V

11

12

13

14

Arc-in-a-box Testing ConditionsParameter Test Set-Up #1 Test Set-Up #2A Test Set-Up #3

Electrode Geometry Vertical Terminated Vertical Non-Terminated Horizontal with smaller box

Electrode Material 0.75” Copper Rod 0.75” Copper Rod 0.75” Copper Rod

Electrode Spacing 1.25” OD to OD 1.25” OD to OD 1.25” OD to OD 4” from back of box 1.5” from back of box 4” from back of box

System Voltage 480V 480V 480V

Arc Current 25 to 50KA 30KA 25 to 50KA

Arc Duration 1 to 20 cycles 1 to20 cycles 1 to20 cycles

Box Dimensions 20” x 20” x 20” 14” x 12” x 7.5” 20” x 20” x 20”

Number of Sensors 2 to 9 4 2 to 9

Distance from Arc to Sensors 10 to 18 12 & 18 10 to 18

16

Material TypeWeight oz/yd2

Air Permeabilityft3/min (cfm)

Arc RatingASTM

F1959-05b Test Method

SS Electrodescal/cm2

Est. Arc RatingIEEE

Box MethodVertical

Cu Electrodescal/cm2

Est. Arc RatingIEEE

Box MethodVertical

Cu Electrodescal/cm2

Est. Arc RatingBox MethodHorizontal

Cu Electrodescal/cm2

Standard Box20” x 20” x 20”

New Small Box14” x 12” x 7.5”

Standard Box20” x 20” x 20”

Standard Box20” x 20” x 20”

HRC4, 2 layersFRT cotton/nylon19 oz/yd2, 5 cfm

41(20 Specimens)

28(2 test panel)

13(1 test panels)

21(3 test panels)

HRC4, Aramid/ Modacrylic fabric 2 layer, 16 oz/yd2

10 to 20 cfm

42(20 Specimens)

29(2 test panels

NA NA

HRC4, 3 layersAramid 12 oz/yd2, 84 cfm

49(20 Specimens)

23(3 test panels)

17(5 test panels)

18(3 test panels

HRC4+ aramid5 layers15 oz/yd2, 59 cfm

70(20 Specimens)

32(3 test panels)

Exceeds Max Exposure for Test Equipment

35(1 test panel)

IEEE Arc-In-a-Box Configuration vs. Ferraz Shawmut Configurations

17

Material TypeWeight oz/yd2

Air PermeabilityIn ft3/min (cfm)

Arc RatingASTM

F1959-05b Test Method

SS Electrodescal/cm2

Est. Arc RatingIEEE

Box MethodVertical

Cu Electrodescal/cm2

Est. Arc RatingBox MethodTerminated

Vertical Cu Electrodes

cal/cm2

Est. Arc RatingBox MethodHorizontal

Cu Electrodescal/cm2

HRC4 over HRC2, Aramid4 layers19 oz/yd2, 16 cfm

65 est. Exceeds Max Exposure for Test

Equipment

20(1 test panel)

22(3 test panel)

HRC4+ aramid5 layers15 oz/yd2, 59 cfm

70 Exceeds Max Exposure for Test

Equipment

27(3 test panels)

35(1 test panel)

HRC4++ aramid 7 layers18 oz/yd2, 49 cfm

106(20 Specimens)

Exceeds Max Exposure for Test

Equipment

60(3 test panels)

45(6 test panels)

HRC4++ aramid 20 oz/yd2, 0 cfm

109 est.(6 Specimens)

Exceeds Max Exposure for Test

Equipment

>60(3 test panels)

50(1 test panel)

HRC4++ aramid 5 layers31 oz/yd2, 4 cfm

140 est.(6 Specimens)

Exceeds Max Exposure for Test

Equipment

NA >50(1 test panel)

IEEE Arc-In-a-Box Configuration vs. Ferraz Shawmut Configurations

18

Preliminary Conclusions

Arc flash heat exposures consist of radiant and convective energy—plasma jets are unique type of convective energy The ratio of radiant and convective heat varies with the equipment configurationASTM test methods have a higher radiant component than convective componentArc-In-a-Box test configurations with horizontal electrodes or vertical electrodes with or without a terminating barrier have a higher convective component than radiant component

19

Recommendations

Expand testing research based on high convective energy arc exposures to additional laboratories

PG&E Testing ProgramKinetrics if funds are available

Create an F18.65 Work Item and draft a proposed test method for balloting