Arc Flash and NFPA 70E

Transcription

1 Arc Flash and NFPA 70E Presented by: J.D. Kyle Safe Work Practices Wearing Proper PPE? OSHA (a) (1) not to work hot or live except : 1. De energizing introduces additional or increased hazards Emerg systems, Life Support. 2. Infeasible due to equipment design or operational limitations - troubleshooting 1

2 35,000 F Electrical Arc Molten Metal Pressure Waves Sound Waves Copper Vapor: Solid to Vapor Expands by 67,000 times Shrapnel Hot Air-Rapid Expansion Intense Light 2012 NFPA 70 E Responsibility Responsibility: The employer shall provide the safety related work practices and shall train the employee, who shall implement them 2

3 110.2 (A) Safety Training For employees who face electrical risk that has not been de-energized. Employees shall be trained to: Understand specific hazards associated with electrical energy Trained in safety related work practices Procedural requirements Trained to identify & understand relationship between electrical hazards and possible injury (D)(1) Qualified Person Qualified Person- Shall be trained and knowledgeable of the construction & operation of equipment or specific work method and be trained to recognize and avoid the electrical hazards that might be present with respect to that equipment or work method. 3

4 110.2 (D)(1) Qualified Person. Continued (a) Such persons shall also be familiar with the proper use of special precautionary techniques -PPE including arc flash suit -insulating and shielding material -insulated tools -and test equipment A person can be qualified with respect to certain equipment and methods but still be unqualified for others (D)(1) Qualified Person. Continued (b)(4) Decision-making process necessary to determine the degree and extend of the hazard and the ppe and job planning necessary to perform the task safely Note: Re-training shall be performed at intervals not to exceed 3 years 4

5 ARC Flash 3 Main Factors Determining an Arc Flash Available Energy (Ka) Distance (inches) Time (sec) (cycles) =Incident Energy=CAL/CM2 11 Cal FR vs. Std Cotton non FR 5

6 25 cal/cm2 suit vs. std non FR plus non FR denim = ~5 cal ARC FLASH ANALYSIS An arc flash hazard analysis shall determine the arc flash boundary, the incident energy at the working distance and the ppe people within the arc flash boundary shall use. Exception: The requirements of 130.7(c)(15) and 130.7(c)(16) shall be permitted in lieu of determining the incident energy at the working distance 6

7 Table 130.7(c)(16) Protective Clothing and PPE Hazard Risk Category Clothing (HRC) 0 Nonmelting flammable (untreated cotton, wool, rayon etc with a fabric weight of at least 4.5 oz 1 Arc-rated FR shirt and FR pants or coveralls 2 Arc rated FR shirt and FR pants or coveralls 3 Arc rated FRsystem to meets required minimum 4 Arcrated system meets required minimum Cal/cm2 Nonmelting clothing at least 4.5 oz Minimum Arc Rating of 4 Minimum arc rating of 8 Minimum Arc Rating of 25 Minimum Arc Rating of 40 7

8 Work Scope Install and verify Phase rotation on line side of a 480 Volt 60 amp Disconnect. Using tables determine level of ppe required D.5 Calculation of Incident Energy for an Arc Flash Analysis 8

9 Work Scope: Install & verify phase rotation on line side of a 480V, 60amp disconnect 480V 600A 13kv 480 V 1200A 480V 2500Kva 480V Utility Main Main, Transformer 600A 3 sec 3500A fuses Determine level of PPE to perform work? 480V 60A Disconnect 480V 600A Various software that can help you conduct an Arc Flash Analysis -Duke Flux calculator -Easy Power Calculator -Arc Advisor 9

10 Work Scope: Install & verify phase rotation on line side of a 480V, 60amp disconnect 480V 600A Utility 13kv 1200A Main 480 V Transformer 480V Main, 1200A 480V 600A A B What point has higher arc flash potential? A or B 480V 600A Incident Energy 10

11 Incident Energy Incident Energy 11

12 Incident Energy! 24 inch Flash Hazard Boundary 3 cal/cm 2 Flash Hazard at 18 inches 1 PPE Level, 1 Layer 6 oz Nomex, Leather Gloves Faceshield 480 VAC Shock Hazard when Cover is removed 36 inch Limited Approach 12 inch Restricted Approach V Class 00 Gloves 1 inch Prohibited Approach V Class 00 Gloves Equipment Name: Slurry Pump Starter Date: Courtesy E.I. du Pont de Nemours & Co. WARNING Arc Flash and Shock Hazard Appropriate PPE Required P25 Review the labels every 5 years or when changes or upgrades occur 12

13 Biggest cause of Death and Burns Human Error 98% 22.6 KA Symmetrical Available Fault 480V, 3 Phase 6 cycle STD 640A OCPD 6 cycle opening Non Current Limiting with Short Time Delay Test No. 4 Fault Initiated on Line Side of 30A Fuse 30A RK-1 Current Limiting Fuse Size 1 Starter 13

14 Arc Flash Sound ft. T2 >225 C / 437 F T3 50 C / 122 F Results: Test No P1 >2160 lbs/sq.ft T1 > 225 C / 437 F > Indicates Meter Pegged 14

15 22.6 KA Symmetrical Available Fault 480V, 3 Phase 601A. Class L Current Limiting Fuse This type of OCPD has a let through of 11KA and clears in ½ cycle Fault Initiated on Line Side of 30A Fuse Test No. 3 30A RK-1 Current Limiting Fuse Size 1 Starter Arc Flash 15

16 Results: Test No.3 = Sound ft. T2 62 C / F T3 P1 504 lbs/sq.ft T1 > 175 C / 347 F (No Change From Ambient) > Indicates Meter Pegged Biggest cause of Death and Burns Human Error 98% 16

17 TURN THE POWER OFF Work out ways to de energize Not the dinosaur method to work on or around it energized NO POWER = NO ARC FLASH or NO SHOCK This is the easiest, quickest and safest Challenge owners or contractors that push to do it energized 17

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