INTRODUCTION ARC FLASH PROTECTION AND SAFETY MEASURES. September 2010

Transcription

1 ARC FLASH PROTECTION AND SAFETY MEASURES September 2010 Introduction Hazards of Electrical Energy Electrical Safety Program Safety-Related Work Practices Electrical Safety Procedures Presented By: Ken Schmerber, MS, CIH, CSP Principal EHS Consultant Hellman & Associates, Inc INTRODUCTION OSHA s 29 CFR (a) - Requires training when employees face a risk of electric shock that is not reduced to a safe level by the electrical installation requirements of through OSHA s (a)(1) - No employer shall permit an employee to work in such proximity to any part of an electric power circuit that the employee could contact the electric power circuit in the course of work, unless the employee is protected against electric shock by de-energizing the circuit and grounding it or by guarding it effectively by insulation or other means. 1

2 INTRODUCTION To be Considered a Qualified Person: Safety-related work practices that pertain to their job assignments. The skills and knowledge necessary to: Distinguish exposed live parts from other parts of electric equipment; and Determine the nominal voltage of exposed live parts. Appropriate clearance distances for the corresponding voltages to which they will be exposed. Construction and operation of the equipment and the hazards involved. Specific hazards associated with electrical energy. Relationship between electrical hazards and possible injury. Applicable emergency procedures. INTRODUCTION Regulations/Standards ( 50 Volts): OSHA 29 CFR 1910, Subpart S, Electrical , Scope , Training , Selection and Use of Work Practices , Use of Equipment , Safeguards for Personal Protection National Fire Protection Association (NFPA) 70E, Standard for Electrical Safety in the Workplace, 2009 Edition Chapter 1 - Safety-Related Work Practices Chapter 2 - Safety-Related Maintenance Requirements Chapter 3 - Safety Requirements for Special Equipment Annexes A - O 2

3 INTRODUCTION NFPA Chapter 1, Safety-Related Work Practices Article Definitions Article General Requirements for Electrical Safety- Related Work Practices Article Establishing an Electrically Safe Work Condition Article Work Involving Electrical Hazards INTRODUCTION Reference Working on Live Parts Qualified Person/Training Approach Boundaries ALL Work Personal Protective Equipment Electrical Safety Program Energized Electrical Work Permit OSHA Subpart S Refers to Subpart I NFPA NFPA 70E Chapter 1 Hazard/Risk Category 3

4 INTRODUCTION HAZARDS OF ELECTRICAL ENERGY Hazards include: Shock; Electrocution; Arc Flash/Blast; and Burns. 4

5 HAZARDS OF ELECTRICAL ENERGY Why is arc flash dangerous? An arc is a source of intense heat, light, sound, and pressure! Colorado in July/August: 100 F Surface of the Sun: 8,540 F Arc at arc terminals: 35,540 F HAZARDS OF ELECTRICAL ENERGY Physical Effects of Arc Blast Metal vapor and air expand very rapidly due to arc heating. Pressure wave (~740 mph; 2,000 psi; ~ 165 db) knocks worker away from arc: Good: removes personnel from heat source Bad: removes personnel from ladder Eardrum rupture Blindness Lung damage Death! Molten metal droplets: Can ignite clothing Cause burns 5

6 HAZARDS OF ELECTRICAL ENERGY How hazardous can it be? HAZARDS OF ELECTRICAL ENERGY Annual Preventative Maintenance Incident 6

7 HAZARDS OF ELECTRICAL ENERGY Live Breaker Replacement Incident HAZARDS OF ELECTRICAL ENERGY Breaker Racking 7

8 ELECTRICAL SAFETY PROGRAM General Implement overall program that is appropriate to manage the degree of hazard Electrical safety procedures are one component LO/TO also plays a critical role Safe Work Procedures Hazard Analysis Coordination Study Shock and Arc-Flash Analysis Job Briefing Personal Protective Equipment Training Auditing ELECTRICAL SAFETY PROGRAM OSHA 29 CFR Safety related work practices shall be employed to prevent electric shock or other injuries resulting from either direct or indirect electrical contact. Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible. Verification that equipment is deenergized can be hazardous. 8

9 ELECTRICAL SAFETY PROGRAM When is it acceptable to work on energized equipment? When it involves: Interruption of life support systems; Deactivation of emergency alarm systems; Shutdown of hazardous location ventilation; and Removal of illumination. Or is infeasible: Diagnostics and testing (e.g., start-up and troubleshooting); and Part of continuous process segment. ELECTRICAL SAFETY PROGRAM Hazard Analysis Coordination Study Electrical Hazard Analysis Shock Hazard Process described in NFPA 70E 130.2, Approach Boundaries to Energized Electrical Conductors or Circuit Parts Arc Flash Hazard Process described in NFPA 70E 130.3, Arc Flash Hazard Analysis Alternative is to use the PPE requirements in NFPA 70E 130.7(C)(9). The table can be used if system meets the limitations in the Note section at the end of the table. 9

10 ELECTRICAL SAFETY PROGRAM Hazard/Risk Evaluation Procedure ELECTRICAL SAFETY PROGRAM Table 130.7(C)(9), Hazard/Risk Classification 10

11 ELECTRICAL SAFETY PROGRAM Table 130.7(C)(9), Notes ELECTRICAL SAFETY PROGRAM Table 130.7(C)(10), PPE 11

12 ELECTRICAL SAFETY PROGRAM Table 130.7(C)(10), Notes ELECTRICAL SAFETY PROGRAM Table 130.7(C)(11), Protective Clothing Characteristics 12

13 ELECTRICAL SAFETY PROGRAM Annex D, Incident Energy and Flash Protection Boundary Calculation Methods ELECTRICAL SAFETY PROGRAM 13

14 ELECTRICAL SAFETY PROGRAM Equipment shall be field marked with a label containing the available incident energy or required level of PPE. ELECTRICAL SAFETY PROGRAM Procedures (Routine) Purpose of task Qualifications and number of employees involved Hazardous nature and extent of task Limits of approach Safe work practices to be utilized Required PPE including insulating materials and tools Electrical diagrams Equipment details Reference data 14

15 ELECTRICAL SAFETY PROGRAM Job Briefing Form (Non-Routine) ELECTRICAL SAFETY PROGRAM Energized Electrical Work Permit (Non-Routine) Used when an electrical system cannot be placed in an electrically safe work condition. 15

16 SAFETY RELATED WORK PRACTICES LOTO Approach boundaries PPE and inspection Others SAFETY RELATED WORK PRACTICES Approach Boundaries and PPE Shock Protection Limited; Restricted; and Prohibited. Flash Protection Distance at which the incident energy is 1.2 cal/cm 2 (i.e., point at which second degree burns may occur). 16

17 SAFETY RELATED WORK PRACTICES Limits of Approach (Figure C-1-2.4) SAFETY RELATED WORK PRACTICES 17

18 SAFETY RELATED WORK PRACTICES Personal Protective Equipment SAFETY RELATED WORK PRACTICES Use the left hand rule Open cabinets from hinged side Ensure there is adequate illumination No blind reaching Do not use over current protection devices as switches Use shielding for enclosed spaces No use of conductive materials or equipment such as metal ladders and apparel Housekeeping 18

19 ELECTRICAL SAFETY PROCEDURES ELECTRICAL SAFETY PROCEDURES Required PPE 19

20 ELECTRICAL SAFETY PROCEDURES Procedure SUMMARY OSHA and NFPA 70E 50 V Qualified Worker Hazards of Electrical Energy Shock Arc Flash Electrical Hazard Analysis Determines PPE level Safety-Related Work Practices Work deenergized LOTO PPE if working energized Electrical Safety Program ESPs Energized Work Permit 20