arc hazard & fr clothing policy review. 2 today’s agenda premise for the arc hazard assessment...
TRANSCRIPT
ARC HAZARD &
FR CLOTHING POLICY REVIEW
2
Today’s Agenda•Premise for the ARC hazard assessment
•Fire Resistant vs. 100% natural fiber clothing
•ARC Hazard evaluation criteria
•ARC Hazard review & Incident ARC energy
•Final Determination
3
RegulationsFederal/OSHA 29 – CFR 1910.269Electric Power Generation, Transmission, and Distribution. -
CAL/OSHA Title - 8§2320.2. Energized Equipment or Systems.
4
The employer shall ensure that each employee who is exposed to the hazards of flames or electric arcs does not wear clothing that, when exposed to flames or electric arcs, could increase the extent of injury that would be sustained by the employee.
Fed OSHA 1910.269(l)(6)(iii)
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Note: Clothing made from the following types of fabrics, either alone or in blends, is prohibited by this paragraph, unless the employer can demonstrate that the fabric has been treated to withstand the conditions that may be encountered or that the clothing is worn in such a manner as to eliminate the hazard involved: acetate, nylon, polyester, rayon.
Fed OSHA 1910.269(l)(6)(iii)
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CAL/OSHA §2320.2. (8) Each employee who is exposed to the hazards of flames or electric arcs wears apparel that, when exposed to flames or electric arcs, does not increase the extent of injury that would be sustained by the employee. This subsection prohibits clothing made from the following types of fabrics, either alone or in blends, unless the employee can demonstrate that the fabric has been treated with flame retardant: acetate, nylon, polyester, and rayon.
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July 28, 1995
Mr. Charles H. WilliamsDirector, Codes and StandardsNational ElectricalContractors Association3 Bethesda Metro Center, Suite 1100Bethesda, MD 20814
Dear Mr. Williams: This is in further response to your letter of April 17, requesting clarification of the electric power generation, transmission, and distribution standard, 29 CFR 1910.269.
Question 1: What types of clothing are acceptable under the 1910.269 Standard?
“The Apparel Standard does not serve to protect workers from direct injury due to electric arc or flame exposure, as would PPE; it simply prohibits clothing that would make even worse any injuries caused by that exposure. Under this rule, flame resistant and flame-retardant-treated clothing is acceptable under all conditions…”
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To protect the employees we will.
1. Engineer the hazard out of the system if possible
2. Put in place - Administrative controls where applicable(Ex. – Shall not perform said work energized)
3. Provide Personal Protective Equipment (PPE) as a last resort
11
Fire Resistant vs.
100% Natural Fiber
12
DefinitionsArc Thermal Performance Value (ATPV)“n – in arc testing, the incident energy on a fabric or material that results in sufficient heat transfer through the fabric or material to cause the onset of a second-degree burn based on the Stoll curve.” Note: ATPV is measured in cal/cm2.
Basically, it is the measure of how much heat that can be exposed to a flame resistant garment before a second degree burn injury is expected to occur to the wearer.
13
Definitions cont.
Breakopen Threshold Energy (EBT)“n – the average of the five highest incident energy exposure values below the Stoll curve where specimens do not exhibit breakopen.” Note: Breakopen Threshold Energy is similar to ATPV,
Heat Attenuation Factor (HAF)“n – in electric arc testing, the percent of the incident energy which is blocked by a material at an incident energy level equal to ATPV.”
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FR Clothing
Cal/cm2 Value for Fire Resistant Clothing
Garment Material & Weight in Ounces per Square Yard of
Fabric Cal/cm2 Value Comments
6.3oz FR Firewear Tee Knit 5.1
7.0oz FR Cotton/Nylon Utility Shirt Twill Weave 6.6
4.5oz FR Cotton/Rayon Utility Shirt Plain Weave 4.54.5oz Nomex Utility Shirt Plain Weave 4.84.5oz FR Henley or Polo Shirt Plain Weave 6.8
14.0oz FR Cotton Jean Denim 16.0
9.0oz FR Duck Pant 12.7
16
Cal/cm2 for Non Fire Resistant Clothing 10% Probability of Ignition
Garment Material & Weight in Ounces per Square Yard of Fabric Cal/cm2 Comments
4.6oz White Jersey Knit Shirt 7.0
5.2oz Blue Twill Shirt 5.5
6.2oz Western White Fleece 10.7
6.9oz Blue Denim Twill Wrangler Shirt 6.9
Calorie capacity goes to 7.9 after washing the garment
8.0oz Black Twill Shirt or Pant 7.4
8.3oz White Sateen Shirt or Pant 14.5
11.9oz Tan Duck Carhart Shirt or Pant 15.0
12.8oz Blue Denim Lee Jeans (Pant) 17.6
13.3oz Blue Denim Wrangler Jeans (Pant) 18.0
Non-FR Clothing
17
FR vs. Non-FR
Fire Resitant ClothingNon-Fire Resistant Clothing
Garment Material & Weight in Ounces per Square Yard of Fabric Cal/cm2
Garment Material & Weight in Ounces per Square Yard of Fabric Cal/cm2
4.5oz FR Cotton/Rayon Utility Shirt 4.5 4.6oz White Jersey Knit Shirt 7
4.5oz Nomex Utility Shirt 4.8 5.2oz Blue Twill Shirt 5.5
6.3oz Firewear Tee 5.1 6.2oz Western White Fleece 10.7
7.0oz FR Cotton/Nylon Utility Shirt 6.6
6.9oz Blue Denim Twill Wrangler Shirt 6.9
9.0oz Duck Pant 12.711.9oz Tan Duck Carhart Shirt or Pant 15
14.0oz FR Cotton Jean 1613.3oz Blue Denim Wrangler Jeans (Pant) 18
Cal/cm2 for Non Fire Resistant Clothing 10% Probability
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ARC Hazard Evaluation Criteria
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•Minimum approach distance used is 12” for 600 volts or less
•For all primary voltages, the required Cal/OSHA minimum approach distances are used
•Work procedures are recognized as a suitable exposure control measure and employees are expected to follow them
•Minimum voltage to consider is 200 volts and above
•Minimum fault at Maximum clearing time (or 600 cycles) used to determine maximum ARC exposure (worst case scenario)
•Used Box-Factor
ARC HAZARD EVALUATION CRITERIA
20
•FR Clothing only required when working on or near exposed energized electrical equipment
•Equipment that can be safely de-energized and worked cold does not require the use of FR clothing
•cal/cm2 < 5.0 does not require FR pants
•Working outside the ARC flash boundary with hot-sticks eliminates the need for FR pants
ARC HAZARD STUDY EVALUATION CRITERIA cont.
21
ARC Hazard Assessment
&
Incident ARC Energy levels
22
Modifications to ARC Hazard Data & Chart• 230Kv, 115Kv & 69Kv reworked with appropriate
clearance distances
• < 5.0 cal/cm2 removed
• Identified Incident ARC energy levels above FR Clothing capabilities (Light Blue)
• Identified Incident ARC energy levels at which a FR Shirt is recommended (Yellow)
23
Revised 12” ARC Hazard DataARC GAP 12" 12" 12" 12"
SYSTEM VOLTAGE 21
kV
21kV
12kV
4160
V
SYSTEM EQUIPMENT B
USS
FEE
DE
R
BU
SS
BU
SS
FUSE
RE
LA
Y
RE
LA
Y
200E
80E
/50E
I (Fault Min) 8,43
7
2,06
9 I (Fault Min) 1,
915
5,35
0
CLEAR (Cycles) 16
8
56
CLEAR (Cycles) 49 10
8
Cal/cm2 @
28" 31.0 1.6Cal/cm
2 @
25" 1.5 14.2
Cal/cm2 @
28" w/B.F. 62.0 3.2Cal/cm
2 @
25" w/B.F. 3.0 28.4
I (Fault Max) 20
,000
20,0
00 I (Fault Max) 7,
500
8,70
0
CLEAR (Cycles) 37
.8
12
CLEAR (Cycles) 10
2
108
Cal/cm2 @
28" 19.4 6.2Cal/cm
2 @
25" 20.4 25.8
Cal/cm2 @
28" w/B.F. 38.8 8.3Cal/cm
2 @
25" w/B.F. 40.8 51.6Meter Techs X
Elec Techs X X X XLineworkers 1,2,3,4,5 X X
Cable Splicers X X XTree Trimmers X 6.2
Substation Electricians X X X X
MINIMUM FAULT AT MAXIMUM CLEARING TIME OR 600 Cycles
MAXIMUM INSTANTANEOUS FAULT
24
4" 4" 4" 4" 4" 4" 1" 1" 1" 1" 1"
4kV
-277
/480
V
4kV
-277
/480
V
4kV
-277
/480
V
4kV
-277
/480
V
4kV
-277
/480
V
4kV
-277
/480
V
4kV
-120
/208
V
4kV
-120
/208
V
4kV
-120
/208
V
4kV
-120
/208
V
4kV
-120
/208
V
750k
VA
PM
500k
VA
PM
300k
VA
PM
225k
VA
PM
150k
VA
PM
112.
5kV
A P
M
500k
VA
PM
300k
VA
PM
225k
VA
PM
150k
VA
PM
112.
5kV
A P
M
140K
100T
65T
50K
30K
25K
100T
65T
50K
30K
25K
I (Fault Min)
12,0
51
7,67
5
4,44
5
3,59
9
2,76
4
2,18
8
13,1
09
7,91
8
5,40
0
3,19
0
2,65
5
CLEAR (Cycles) 66 204
234
59 35 41 522
600
348
600
360
Cal/cm2 @ 12" 45.5 78.9 45.6 8.9 3.8 3.2 148.0 80.4 27.0 22.5 10.3
Cal/cm2 @ 12" w/B.F. 91.0 157.8 91.2 17.8 7.6 6.4 296.0 160.8 54.0 45.0 20.6
AMPS14
,237
10,3
30
6,66
6
5,14
5
3,91
7
2,98
7
19,7
32
13,5
20
10,7
14
8,32
1
6,44
9
CYCLES 54.6
96 56.8
27 16.2
19.2
150
96 34.2
19.8
22.2
Cal/cm2 @ 12" 47 54.1 18.4 6.3 2.7 2.3 81.0 28.5 7.1 2.9 2.2
Cal/cm2 @ 12" w/B.F. 94.0 108.2 36.8 12.6 5.4 4.6 162.0 57.0 14.2 5.8 4.4
Meter Technicians at 12" Approach X X X X X X X X X X XElectric Technicians at 12" Approach
Troubleshooters at 12" Approach X X X X X X X X X X XLineworker 1,2,3,4,5 at 12" Approach X X X X X X X X X X X
Cable Splicers / Network at 12" ApproachTree Trimmers at 12" Approach
Power Quality Technicians at 12" Approach X X X X X X X X X X XSubstation Electricians at 12" Approach
MINIMUM FAULT AT MAXIMUM CLEARING TIME OR 600 Cycles
MAXIMUM INSTANTANEOUS FAULT
ARC GAP
SYSTEM VOLTAGE
Tables 2,4,and 5 SYSTEM
FUSE
25
4" 4" 4" 4" 4" 4" 4" 4" 1" 1" 1"
12kV
-277
/480V
12kV
-277
/480V
12kV
-277
/480V
12kV
-277
/480V
12kV
-277
/480V
12kV
-277
/480V
12kV
-277
/480V
12kV
-277
/480V
12kV
-120
/208V
12kV
-120
/208V
12kV
-120
/208V
1500
kVA
PM
1000
kVA
PM
750k
VA
PM
500k
VA
PM
300k
VA
PM
225k
VA
PM
150k
VA
PM
45kV
A P
M
500k
VA
PM
300k
VA
PM
225k
VA
PM
100T
80K
50K
40K
25K
15K
12K
2.5X
40K
25K
15K
I (Fault Min)
22,5
75
16,1
51
11,8
52
9,08
6
5,52
9
5,69
6
4,60
6
2,28
3
12,9
33
8,21
0
6,04
3
CLEAR (Cycles) 180
72 43 52 50 17 15 31 318
246
114
Cal/cm2 @ 12" 293.0 73.4 29.0 24.9 12.8 4.5 3.1 2.6 88.6 34.7 10.4
Cal/cm2 @ 12" w/B.F. 586.0 146.8 58.0 49.8 25.6 9.0 6.2 5.2 177.2 69.4 20.8
AMPS25
,021
17,8
88
13,9
40
13,0
83
9,13
5
10,9
24
9,25
1
3,19
5
20,0
85
16,2
22
13,9
31
CYCLES 51 49.2
28.8
21 16.2
4.68
3.84
16.8
50.4
25.8
14.4
Cal/cm2 @ 12" 96.0 58.0 24.1 16.1 7.8 2.8 1.9 2.2 28.0 10.2 4.2
Cal/cm2 @ 12" w/B.F. 192.0 116.0 48.2 32.2 15.6 5.6 3.8 4.4 56.0 20.4 8.4
Meter Technicians at 12" Approach X X X X X X X X X X XElectric Technicians at 12" Approach X X X X
Troubleshooters at 12" Approach X X X X X X X X X X XLineworker 1,2,3,4,5 at 12" Approach X X X X X X X X X X X
Cable Splicers / Network at 12" ApproachTree Trimmers at 12" Approach
Power Quality Technicians at 12" Approach X X X X X X X X X X XSubstation Electricians at 12" Approach X X X X
MINIMUM FAULT AT MAXIMUM CLEARING TIME OR 600 Cycles
MAXIMUM INSTANTANEOUS FAULT
ARC GAP
SYSTEM VOLTAGE
Tables 2,4,and 5 SYSTEM
FUSE
26
1" 1" 1" 1" 4" 4" 4" 4" 4" 4" 1"
12kV
-120
/208V
12kV
-120
/208V
12kV
-120
/208V
12kV
-120
/208V
21kV
-277
/480V
21kV
-277
/480V
21kV
-277
/480V
21kV
-277
/480V
21kV
-277
/480V
21kV
-277
/480V
21kV
-120
/208V
225k
VA
PM
150k
VA
PM
112.
5kV
A P
M
45kV
A P
M
2500
kVA
PM
2000
kVA
PM
1500
kVA
PM
1000
kVA
PM
750k
VA
PM
500k
VA
PM
500k
VA
PM
15K
12K
10K
2.5X
100T
80K
65T
40K
30K
20K
20K
I (Fault Min)
6,04
3
3,35
0
3,35
9
2,20
5
36,9
13
28,9
30
23,7
97
16,7
70
11,0
44
9,27
6
13,1
01
CLEAR (Cycles) 114
600
150
222
59 17 53 12 17 10 28
Cal/cm2 @ 12" 10.4 24.1 6.0 4.8 199.0 39.6 92.9 12.9 10.5 4.9 7.9
Cal/cm2 @ 12" w/B.F. 20.8 48.2 12.0 9.6 398.0 79.2 185.8 25.8 21.0 9.8 15.8
AMPS13
,931
11,9
52
13,1
36
6,00
8
41,8
15
34,8
58
27,2
94
19,0
21
14,5
91
13,6
70
20,7
54
CYCLES 14.4
11.4
7.2
23.4
48 12.6
39 9.2
11.4
4.62
10.2
Cal/cm2 @ 12" 4.2 2.8 2.0 2.1 196.0 39.0 83.0 11.7 10.1 3.8 6.0
Cal/cm2 @ 12" w/B.F. 8.4 5.6 4.0 4.2 392.0 78.0 166.0 23.4 20.2 7.6 12.0
Meter Technicians at 12" Approach X X X X X X X X X X XElectric Technicians at 12" Approach
Troubleshooters at 12" Approach X X X X X X X X X X XLineworker 1,2,3,4,5 at 12" Approach X X X X X X X X X X X
Cable Splicers / Network at 12" Approach X X X X X X XTree Trimmers at 12" Approach
Power Quality Technicians at 12" Approach X X X X X X X X X X XSubstation Electricians at 12" Approach
MINIMUM FAULT AT MAXIMUM CLEARING TIME OR 600 Cycles
MAXIMUM INSTANTANEOUS FAULT
ARC GAP
SYSTEM VOLTAGE
Tables 2,4,and 5 SYSTEM
FUSE
27
1" 1" 1" 1" 1" 4" 4"
21kV
-120
/208V
21kV
-120
/208V
21kV
-120
/208V
21kV
-120
/240V
12kV
-120
/208V
12kV
-277
/480V
21kV
-277
/480V
300k
VA
PM
225k
VA
PM
75kV
A P
M
167k
VA
OH
NE
TW
OR
K
SPO
T
NE
TW
OR
K
SPO
T
NE
TW
OR
K
12K
10K
2.5X
20K
I (Fault Min)
8,27
7
6,07
8
2,56
5
9,77
3
N/A
N/A
13,3
44
CLEAR (Cycles) 25 29 144
40 * * 600
Cal/cm2 @ 12" 3.6 2.7 3.9 7.3 * * 480
Cal/cm2 @ 12" w/B.F. 7.2 5.4 7.8 14.6 * * 960
AMPS
16,6
52
14,2
44
9,80
0
35,4
35
175,
000
156,
041
52,3
00
CYCLES 6.6
4.98 9
2.82 54 54 54
Cal/cm2 @ 12" 2.7 1.6 1.6 4.2 480 953 316
Cal/cm2 @ 12" w/B.F. 5.4 3.2 3.2 * 960 1906 632
Meter Technicians at 12" Approach X X X X X X XElectric Technicians at 12" Approach
Troubleshooters at 12" Approach X X X XLineworker 1,2,3,4,5 at 12" Approach X X X X
Cable Splicers / Network at 12" Approach X X X X X X XTree Trimmers at 12" Approach X
Power Quality Technicians at 12" Approach X X X XSubstation Electricians at 12" Approach
MINIMUM FAULT AT MAXIMUM CLEARING TIME OR 600 Cycles
MAXIMUM INSTANTANEOUS FAULT
ARC GAP
SYSTEM VOLTAGE
Tables 2,4,and 5 SYSTEM
FUSE
28
Job Classification Type of Work
Proximity to Work
System Voltage Comments
Meter Technicians (Mike Paulson) Setting/Pulling Meters
12" Upper Body Exposure 4, 12 & 21kV
Lower body exposure minimal 100% nat. fiber pants OK
Electric Technicians (Gil Canady)
Testing for proper operation
12" Upper Body Exposure 4, 12 & 21kV
All equip made cold by electricians or in few s ituations made cold by elec tech w/hot-s ticks . Testing equipment 10kV operated by switches
Troubleshooters (Jim Baird)
Diagnosis /minor repair on equipment
12" Upper Body Exposure
4, 12, 21,& 69kV
Voltages Equal to and less than 4kV is hands on type work; including meters . All else is hotline application.
Line worker 1,2,3,4,5 (Max Fuentes)
Installing/removing lines , equipment, and devices . Maintenance and troubleshooting the aforementioned.
12" Upper Body Exposure with 24" lower body exposure
4Kv - 230kV
The line divis ion works on all of the conductors , equipment, devices and s tructures related to the transmiss ion and dis tribution network infras tructure outs ide of the other electrical divis ions and sometimes in conjunction with them.
Cable Splices / Network (Chris Trinidad)
Splice cable service network protectors and the network outages ins tall services
12" Upper Body Exposure
4Kv - 230kV glove 480kV and lower
All large voltage conductors and equipment are insulated to protect employee from electrical contact. Will not work any voltage above 480 energized
Tree Trimmers (Mark Frizzell)
Tree trimming to maintain required clearances
No closer than 25" to 4 & 12 kV. No closer than 28" to 21 kV. No closer than 36" to 69 kV. 4,12,21kV
Apply spreader on secondary voltage (rubber gloved) only when conducter is not covered to prevent tree branches from forcing conducters togther
Power Quality Technicians
Install/Remove voltage recorders for res /comm
Within 6" of forearm; 24" from chest 4Kv - 21kV
480v equipment and below worked hot all else worked cold remove/ins tall meters inspect customer breakers
Substation Electricians (Gil Canady)
Maintaining Substation equipment
Full body exposure on some, 12" upper body on most
All equip made cold by electricians w/hot-s ticks . Testing equipment 10kV operated by switches
29
Strictly enforce the clearance distances mandated by Cal/OSHA. This would greatly reduce the extent of the injury from an ARC.Additionally, strict enforcement of the clearance distances will reduce the potential for electrical contact.
Continue working equipment cold whenever possible
Ground it
Always position body to the side of any electrical source or exposure when possible
30
International Social Security Association (ISSA)
31
Final Requirements for FR Clothing• All employees who work on or near exposed
energized electrical conductors will wear 100% natural fiber pants at or above 11oz/yard and a Fire Resistant garment from the waist up.
• At no time will the employee wear garments made with polyester, nylon, rayon or acetate alone or in blends unless it is FR rated.
• Note: these fabrics shall not be worn under FR garments as either.
32
QUESTIONS?