Preventing Arc Flash Injuries: Engineering is A Science, Safety is a Culture

Transcription

1 Preventing Arc Flash Injuries: Engineering is A Science, Safety is a Culture Presented by: Khadijah Latiff Date: July 25, 2013

2 Greeley and Hansen has met the standards and requirements of the Registered Continuing Education Program. Credit earned on completion of this program will be reported to RCEP at RCEP.net. A certificate of completion will be issued to each participant. As such, it does not include content that may be deemed or construed to be an approval or endorsement by RCEP. 2

3 Greeley and Hansen's Intellectual Property Please be aware that this presentation has been developed for the exclusive use of Greeley and Hansen personnel for training and other specific purposes. As such, it is considered to be the firm's intellectual property and is not to be shared with persons external to the firm or other organizations. For additional information, refer to Greeley and Hansen s Employee Policy 104 Non-Disclosure and Confidentiality 3

4 Topics 1. Introduction to Electrical Hazards 2. Organizational and Behavioral Aspects of Safety 3. Electrically Safe Environment 4. Arc Flash Study, PPE, Electrical Safety Program 4

5 Introduction

6 Definitions Terminology Live / Energized / De-energized Personal Protective Equipment (PPE) Electrical Equipment Short circuit Fault current Protective device 6

7 Resources NIOSH National Institute of Occupational Safety and Health 7

8 Shock Hazard vs Arc Flash Electrical Hazards Contact with current-carrying conductor Arc Flash Arc Blast Electric Shock Arc blast is a high pressure sound wave caused by an arc fault Electric arc high temperature discharge of current through air 8

9 Shock Hazard vs. Arc Flash 1. Shock Hazard: Current, I = V / R body Current path ~5mA pain/perception ~10mA let-go-threshold ~100mA (0.1A) heart fibrillation, skin burns 9

10 Shock Hazard vs. Arc Flash 1. Shock Hazard: VOLTAGE Higher the Voltage, Higher the Hazard Defines Limited Approach Boundary Restricted Approach Boundary Prohibited Approach Boundary 10

11 Shock Hazard vs. Arc Flash 1. Arc Flash Energy: Available fault current AND fault clearing time Available fault current (I sc ) Protective device fault clearing time (t = s) Higher exposure time, higher the hazard Defines Arc Flash Boundary 11

12 Arc Flash Hazard 12

13 Determining the Flash Protection Boundary 1. Distance within which second degree burn is possible 2. Based on arc flash incident energy (cal/ cm 2 ) cal/cm 2 is threshold for onset of second degree burn 13

14 Causes of Arc Flash Main Causes Improper equipment/ system design Negligent preventative maintenance Human error 14

15 Discrepancy in Approach Equipment Failure Human Error Engineering Human Behavior Design 15

16 Existing Approach to Arc Flash 1. Regulatory OSHA 29CFR 1910 NFPA 70E NEC article IEEE Technical Electrical and Arc Flash Hazard Analysis Personal Protective Equipment (PPE) Equipment marking (labels) 3. Arc Flash Mitigation Technologies Arc Flash resistant switchgear Optical or arc pressure sensors High resistance grounding equipment What are we missing? 16

17 Risk Assessment Model Safety Management Design Control Design Engineering Hazard Identification Arc rated equipment Protective Devices Information (study) Organization (administrative and behavioral controls) Communication System that increases awareness Training/Procedures Work organization & instruction Personal protective equipment Verification, validation, documentation 17

18 Organizational and Behavioral Aspects of Safety

19 Importance of Safety Mentality I have sat through safety meetings before, thinking the whole time that the only reason for the meeting was to meet some company insurance requirement or the company just trying to cover itself in case an accident happened." - experienced service electrician, trained What could possibly happen, as long as I am careful? I have done this a million times before. All that (PPE) gear is so hot and bulky. 19

20 NIOSH Study (Electrocution Deaths ) 90 Rate per 100,000 Workers or > 411 deaths by electrocution per year 20

21 NIOSH Study (Electrocution Deaths ) 1. Contributing Factors: Safe work procedures not implemented or followed PPE was not provided or worn LOTO procedures not implemented or followed Lack of compliance with OSHA, NEC, NESC Inadequate worker and supervisor training 21

22 Negative Habits 1. Hard mentalities: Complacency Arrogance Ignorance Incompetence Silence 22

23 Negative Habits 1. Complacency Putting comfort ahead of safety Underestimating risks in performing routine tasks Habit of relying on experience Neglect of housekeeping, maintenance, cleanliness of workplace 23

24 Negative Habits 1. Arrogance Knowingly violating safety rules and procedures Taking shortcuts to save time Performing work without approved energized work permit Treating job briefings and training as mere formality 24

25 Negative Habits 1. Ignorance Inability to recognize source of hazard Accidents involving unqualified persons in hazardous areas 25

26 Negative Habits 1. Incompetence Lack of specific training Lack of job preparation Fail to think through job Under pressure to the point of incompetence 26

27 Negative Habits 1. Silence Seeing unsafe work conditions and not speaking up Fear of blame or negative action from management 27

28 Investing in Values and Culture 1. A complicated safety implement is only as good as the operator operating it 2. An electrical hazard assessment report is only good if it is used and understood 3. An arc flash hazard label is only good if it is readable and understood 4. PPE is only good if it is WORN 5. Values and culture will outlast any technology 28

29 Creating Electrically Safe Environment

30 Fundamentals of Electrical Safety 1. De-energize and isolate 2. Test, to verify equipment de-energized 3. Having clearly defined justifications and required authorization for energized work permit 30

31 Energized Work Permit 1. Part I To be completed by requester Description of circuit, equipment, location Description of work 31

32 Energized Work Permit 1. Part II To be completed by person doing the work Must be an electrically qualified person Detailed description of procedures Description of safe work practices to be employed Documentation of hazard analysis and job briefing 32

33 Energized Work Permit 1. Part III Approval Maintenance/Engineering Manager Electrically Knowledgeable Person Safety Manager Operations Manager General Manager 33

34 Work Permit Flow Chart Is potential exposure to energized parts less than <50V? No Yes Yes Are there other sources of hazard, ie capacity of source, overcurrent protection between source and worker? No Follow safe work practice, wear appropriate PPE and complete the task Can an electrically safe work condition be established (ie Yes Coordinate shutdown. Follow LO/TO procedures No Refer to task table for guidelines on permit requirement. Is No Request denied Yes Obtain Energized Electrical Work Permit and begin assesment All levels of approval not Live work is not justified according to criteria (increased hazards when coordinating shutdown, infeasibility to de-energize due to equipment design or Live work is justified and all levels of approval obtained

35 Arc Flash Study, PPE & Equipment Labels

36 Power Systems Analysis 1. Short circuit study available fault current 2. Coordination study shows coordination of protective devices 3. Arc Flash study provides incident energy, hazard risk category, PPE 36

37 Hazard Risk Categories As determined by Arc Flash study Incident Energy Hazard Risk Category Less than 1.2 cal/cm cal/cm cal/cm cal/cm cal/cm 2 4 Above 40 cal/cm 2 Dangerous! 37

38 Simplified Two-Category Clothing System Clothing Everyday Work Clothing Arc-rated long-sleeve shirt with Arc-rated pants (minimum arc rating of 8) or Arc-rated coveralls (minimum arc rating of 8) Arc Flash Suit A total clothing system consisting of arc-rated shirt and pants and/or arc-rated coveralls and/or arc flash coat and pants (clothing system minimum arc rating of 40) Hazard/Risk Category 0, 1, 2 3, 4 Table H.2 Simplified, Two-Category, Arc-Rated Clothing System Head protection, hearing protection Insulated, arc-rated gloves Safety glasses/goggles Leather work shoes 38

39 Arc Flash Suit 1. Common cause of disregard: Discomfort Obstructed vision Interferes with task 39

40 Equipment Marking NEC Article NFPA 70E 130.5(C) To think about: Quality (information, readability) Context (general, specific, understandable?) Quantity (too many, too few) Placement (visibility) 40

41 Electrical Safety Program

42 Electrical Safety Program Electrical Safety Program (A) General. The employer shall implement and document an overall electrical safety program that directs activity appropriate for the electrical hazards, voltage, energy level, and circuit conditions. (B) Awareness and Self-Discipline. The electrical safety program shall be designed to provide an awareness of the potential electrical hazards to employees who work in an environment with the presence of electrical hazards. The program shall be developed to provide the required self-discipline for all employees who must perform work that may involve electrical hazards. The program shall instill safety principles and controls. NFPA 70E 42

43 Electrical Safety Program Electrical Safety Program should outline: 1. Principles Training, skills assessment, hazard identification, policies, maintenance, anticipate unexpected events 2. Controls Precautions and steps, methods, de-energizing safely, categorization of tasks and PPE level 3. Procedures Qualifications, job briefing, limitations, electrical diagrams, reference material, checklist, PPE, tools, limits of approach 43

44 Electrical Safety Program 1. Think about: Developing electrical safety program that is site specific, not cut-and-paste job Employees have different skill and experience levels Updated periodically with system upgrades Perform electrical safety auditing Document training and retraining 44

45 Challenges 1. Working with contractors and outside service personnel Host employer responsibilities Job briefings, site review, documentation Importance of having a qualified, trained, knowledgeable person to assist contractors 45

46 Summary 1. Safety is not merely compliance Human error is a variable factor Human behavior is complex Attitude towards hazard and danger largely depend on the understanding/awareness 2. Creating a safety culture Addressing behavioral component Creating awareness and self discipline Using knowledge and judgment 3. There is no one-size fits all solution 46

47 Thank you for your time! QUESTIONS? This concludes the educational content of this activity 47

48 SAVE THE DATE! May 23, 2013 at 12pm CST Sustainable Design Challenge By: John Lenti

49 Answers to Quiz 1. a) 2. a) 3. b) 4. b) 5. c) 6. d) 7. a) 8. b) 9. d) 10. a) 49