What you dont know can hurt you ARC

What you don’t know, can hurt you! ARC FLASH Arc Flash in Water and Wastewater Utilities Imagine the result

Overview • What is an Arc Flash? • Why are we concerned? • How will operations be impacted?

What is an Arc Flash?

What is an Arc Flash? • Definitions • Arc Flash: The result of a rapid release of energy due to an arcing fault between a phase bus bar and another phase bus bar or ground (line-to-line or line-to-ground). During an arc fault, air is the conductor. • Arc Flash Hazard: A dangerous condition associated with the possible release of energy caused by an electric arc. (NFPA 70 E)

Arc Flash Hazard • As much as 80% of all electrical injuries are burns resulting from an arc-flash and ignition of flammable clothing • Arc temperature can reach 35, 000°F - this is four times hotter than the surface of the sun • Serious injury can occur at distances over 10 ft. • Over 2000 people are admitted into burn centers each year with severe electrical burns Imagine the result

Products of an Arcing Fault 35, 000 °F Molten Metal Smoke Inhalation Pressure Waves Sound Waves Shrapnel Copper Vapor: Solid to Vapor Expands by 67, 000 times Hot Air-Rapid Expansion Intense Light

Arc Flash Study Purpose of Study: • Provide information needed so that workers can properly assess the risks of arc flash. • Comply with Arc Flash Safety standards. Function of Study: • Quantify the heat or incident energy (cal/cm 2) generated from an arcing fault current. • Identify heat at working distance • Identify the clearance distance from the arc in order to prevent 2 nd degree burns. Other factors, such as sound, pressure blasts, and shrapnel are also associated with arcing faults, but are not quantified in the study.

Arc Flash Study • Arc Flash Study Methodology: • Data collection on-site of all existing electrical components • Re-create one-line diagram in software • Establish available short circuit current • Quantify/ model Available Incident Energy produced from an Arc Flash at each node • Incident Energy is calculated based on available short circuit current and protective device settings • Create Arc Flash Labels • Rollout Meeting • Training

Why are we concerned?

Why are we concerned? • Personnel Safety • Arc Flash events have resulted in injuries to and/or death of workers • Effort to minimize arc flash events and related damage by increasing personnel awareness of potential hazards

Limitations of the Human Body • Second Degree Burn: • Third Degree Burn: • Eardrum Rupture: • Lung Collapse: 175 o. F 205 o. F (0. 1 second) 160 d. B (720 lbs/sq. ft. pressure) 1, 800 lbs/sq. ft. pressure

IEEE Test Case

Imagine the result

Results: Test Case Sound 141. 5 db @ 2 ft. T 2 P 1 >2160 lbs/sq. ft > 437 F T 1 >437 F T 3 122 F > Indicates Meter Pegged

Safety Regulations & Work Practices

Why are we concerned? • NFPA 70 E - Electrical Safety Requirements for Employee Workplaces • Formed to assist OSHA in preparing electrical safety standards that would serve OSHA’s needs • Article 130: Provide analysis and calculations for the degree of arc flash hazard for electrical systems • Incident Energy; Boundary Distances; Personal Protective Equipment (PPE) Requirements • OSHA Regulation • Mission: To assure safe and healthful working conditions for working men and women.

What will change?

What will change? • Safest option is to perform electrical work only on de-energized equipment… • However, this has not always been practical or economical. • Maintenance on Live Equipment • Procedures that Categorize the risk associated with working on energized electrical equipment.

Training Objectives • Be able to identify electrical safety hazards. • Recognize the steps needed to work safely on or near live parts. • Analyze work tasks and select appropriate PPE. • Understand the information provided on the arc flash labels.

Working Distance • The probable distance that a worker’s face and chest would need to be from a “live” part in order to work comfortably. • Note that this distance is from the live part, and not from the front of the cabinet.

Establishing Boundaries • Four boundaries must be established by the worker when working on live equipment: • Flash Protection Boundary • 1. 2 calories/ cm 2 (2 nd Degree Burn) • Limited Approach Boundary (shock) • Persons with Qualified escort only • Restricted Approach Boundary (shock) • Qualified Persons only • Prohibited Approach Boundary (shock) • Considered making contact with live equipment

Electrical Approach Boundaries

Arc Flash Labels • Each label provides information on. . . • Shock boundaries • Arc flash boundary • Working distance • Incident energy exposure at working distance • Hazard-Risk Category (HRC) • Appropriate PPE at working distance

Arc Flash Labels Color Coding: • RED: (DANGER) Incident Energy exceeds 40 cal/cm 2. No live work is permitted on this equipment. • ORANGE: (WARNING) Live work is permitted if live work is justified and the appropriate PPE is worn.

Hazard-Risk Categories (HRC) • The risk of injury from an arcing fault is directly related to the level of incident energy exposure produced from the arcing fault. • NFPA 70 E defines five Hazard-Risk Categories (HRC). PPE requirements are based on these five categories.

PPE Requirements • Based on available Incident Energy • Category 0: 1 to 1. 2 cal/cm 2 • Shirt of non-melting material • Category 1: 1. 2 to 4. 0 cal/cm 2 • Flame Retardant Shirt and Pants • Category 2: 4. 0 to 8. 0 cal/cm 2 • Category 1 gear plus cotton under wear • Category 3: 8. 0 to 25. 0 cal/cm 2 • Category 2 gear plus FR Coveralls • Category 4: 25. 0 to 40. 0 cal/cm 2 • Category 3 gear plus multi layer flash suit

Summary • What is an Arc Flash? • Dangerous explosive energy • Why are we concerned? • Personnel Safety • What will change? • Procedures for maintenance on live electrical equipment • Awareness, Labels, PPE

Arc Flash Experience • Detroit Water and Sewerage Department (DWSD) • 5 Water Treatment Plants and 17 Booster Stations • Wastewater Treatment Plant and 8 Pumping Stations • New York City Department of Environmental Protection (NYC DEP) • 14 Wastewater Treatment Plants and 6 Pumping Stations • Cleveland Water Division • 3 Water Treatment Plants and 11 Booster Stations • 2 Water Division Administrative Facilities • Others

Questions?

Thank You Imagine the result