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 Regulations Federal/OSHA 29 – CFR 1910.269 Electric 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)
5 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)
6 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.
7 May 27, 2003 The Honorable Frank Lautenberg United States Senate Washington, D.C 20510 Dear Senator Lautenberg: “…Because 1910.269 simply restricts the types of clothing employees may wear while working near electrical energy sources capable of producing electric arcs or flames, and does not include any affirmative requirements for fire-resistant or other types of clothing, the issue of who pays for the clothing does not arise. Sincerely, John L. Henshaw Assistant Secretary
8 July 28, 1995 Mr. Charles H. Williams Director, Codes and Standards National Electrical Contractors Association 3 Bethesda Metro Center, Suite 1100 Bethesda, 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…”
9 This means that if the employee is wearing fire resistant clothing; the EMPLOYER will be in compliance with the regulation. It does not mean the employee is protected from an ARC! Therefore, fire resistant clothing is not personal protective clothing it is “COMPLIANCE CLOTHING”
10 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
12 Definitions Arc Thermal Performance Value (ATPV) “ n – in arc testing, t he 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.”
14 Definitions cont. Stoll curve Characterizes the limit of the onset of 2nd degree burn injury to human skin. Incident energy Ei Incident energy in electric arc testing describes the total heat energy received at a surface as a direct result of an electric arc (kWs/m2, kJ/m2 or cal/cm2).
15 FR Clothing Cal/cm 2 Value for Fire Resistant Clothing Garment Material & Weight in Ounces per Square Yard of Fabric Cal/cm 2 Value Comments 6.3oz FR Firewear Tee Knit5.1 7.0oz FR Cotton/Nylon Utility Shirt Twill Weave6.6 4.5oz FR Cotton/Rayon Utility Shirt Plain Weave4.5 4.5oz Nomex Utility Shirt Plain Weave4.8 4.5oz FR Henley or Polo Shirt Plain Weave 6.8 14.0oz FR Cotton Jean Denim 16.0 9.0oz FR Duck Pant12.7
16 Cal/cm 2 for Non Fire Resistant Clothing 10% Probability of Ignition Garment Material & Weight in Ounces per Square Yard of Fabric Cal/cm 2 Comments 4.6oz White Jersey Knit Shirt7.0 5.2oz Blue Twill Shirt5.5 6.2oz Western White Fleece10.7 6.9oz Blue Denim Twill Wrangler Shirt6.9 Calorie capacity goes to 7.9 after washing the garment 8.0oz Black Twill Shirt or Pant7.4 8.3oz White Sateen Shirt or Pant14.5 11.9oz Tan Duck Carhart Shirt or Pant15.0 12.8oz Blue Denim Lee Jeans (Pant)17.6 13.3oz Blue Denim Wrangler Jeans (Pant)18.0 Non-FR Clothing
19 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/cm 2 < 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/cm 2 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)
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.
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