SASCO NFPA 70E Training

Why Electrical Safety Practices and Procedures? 1.An estimated 30,000 non-fatal electrical shock accidents occur each year 2.Over 600 people die from electrocution each year 3.Electrocution remains the fourth highest cause of industrial fatalities 4.Approximately 3000 reported flash burn incidents reported annually, along with approximately 350 deaths. SASCO Arc Flash Training

NFPA 70E—Standard for Electrical Safety in the Workplace –Title: Standard for Electrical Safety for Employee Workplaces –Began 1976 by NFPA. Guidance for OSHA

Electrical Hazards Addressed in NFPA 70E Shock Arc Flash & Arc Blast Fire Ignition

Heat: Fatal burns can occur when the victim is several feet from the arc. Serious burns are common at 10 feet. Tests show heat greater than 437ºF on the neck and hands for a person near an arc blast. Objects: Arcs spray droplets of molten metal at high pressure. Shrapnel can penetrate the body. Pressure: Blast pressure waves can throw workers across rooms or knock them off of ladders. Pressure can reach 2000lbs/sq.ft. Clothing can be ignited several feet away. Hearing loss. Sound pressure can reach 140dB at 2 feet from arc. Mechanisms of Injury

Shock

The Effects of Shock Immediate –Muscle contraction –Vital Organ Damage (Heart, Lungs, etc.) –Tingling –Pain –Breathing –Disorientation –Dizziness Long Term –Memory loss –Nervous disorders –Chemical imbalance –Damage to vital organs –Sometimes fatal

The Effects of Current on the Body

Burns

Two Types of Burns from Shock Surface Burns –Entrance and exit of a electrical currents through the body –Can be a very small amount of current –1 st to 3 rd degree

Two Types of Burns from Shock Internal Tissue burns –From current running through the organs of the body –Currents in excess of 1.5 amps –3 rd degree burns –Damage to internal organs –Often fatal

One Type of Burn From Arc Flash Surface Burns –From exposure to arc flash –Can cause more surface burns if the initial arc ignites other material, such as clothing –1st degree to third degree burns –Has caused death

Probability of Survival The probability of surviving burns decreases with age:

How to Prevent Shock? 1.Place circuits in an electrically safe working condition by locking out and tagging out all energy sources –NFPA 70E-2004: Chapter 1, Section (D) 2.Verify that no electrical energy is present –NFPA 70E-2004: Chapter 1, Section (D)

Fire Ignition from Arc Flash

Exposure to Danger The National Electric Code (NEC) was designed to protect individuals from shock hazards under normal conditions. It is not designed to protect employees under abnormal conditions. We need additional policies to protect us under abnormal conditions.

This is normal somewhere in the world

Notes From Practical Guide to Arc Flash Hazards, By Chet Davis, P.E.; Conrad St. Pierre; David Castor, P.E.; Robert Luo, PhD; and Satish Shrestha Electrical arcs produce the highest temperatures on earth—up to 35,000ºF. That’s 4 times the temperature of the sun. The intense heat from arc causes the sudden expansion of air that results in a blast with very strong air pressure. (Lightning is a natural arc.) All known materials vaporize at this temperature. –Copper expands 67,000 times; Water expands 1670 times. What NFPA 70E is designed to take into account:

Arc Flash Characteristics Arcs in enclosures, such as Motor Control Centers (MCCs) or switchgear, magnify blast and energy transmitted as the blast is forced to the open side of the enclosure. Arcs spray droplets of molten metal at velocity and pressure. Shrapnel can penetrate the body Blast pressure waves have thrown workers across rooms and knocked them off of ladders. Pressure to the chest can exceed 2,000 lbs/sq. ft. Notes From Practical Guide to Arc Flash Hazards

Arc Flash Characteristics Clothing can be ignited from several feet away. Clothed areas can burn more severely than exposed skin. Hearing loss from sound blast. The sound can have a magnitude as high as 140 dB at distance of 2 feet from the arc. Energy released is a function of: –System voltage –Fault current magnitude –Fault duration Notes From Practical Guide to Arc Flash Hazards

How to Protect Against Shock and Arc Flash/Blast? NFPA 70E-2004 –Chapter 1, Section Justification for Live Work 2.Work Permits Secured—If Applicable 3.Approach Boundaries Established Shock Protection Limited Boundary Note: De-energization is covered in Section 120

OSHA (a) (1) and NFPA 70E Qualified electrical workers shall not be asked to work on equipment that is “live” except for two demonstrable reasons: 1.Deenergizing introduces additional or increased hazards Example: Cutting ventilation to a hazardous location OR: 2. Infeasible because of equipment design or operational limits Example: Volt testing for diagnostics

Energized Electrical Work Permit NFPA (A) (1): –“If live parts are not placed in an electrically safe work condition (i.e., for the reasons of increased or additional hazards of infeasibility per 130.1), work to be performed shall be considered energized electrical work and shall be performed by written permit only.”

Elements of an Energized Electrical Work Permit

Results of Flash Hazard Analysis Results of Shock Hazard Analysis Justification for energized work Description of circuit/equipment Description of work location Shock Approach Boundaries PPE Required to do job The Flash Protection Boundary

Work Approvals Keeping unqualified employees away Safe Work Practices } Remember the 4 D’s: If you didn’t document it, you didn’t do it Keeping unqualified employees away Documented Job Briefing

Exemptions to Work Permit “Work performed on or near live parts by qualified persons related to tasks such as testing, troubleshooting, voltage measuring, etc., shall be permitted without energized electrical work permit, provided appropriate safe work practices and person protective equipment in accordance with Chapter 1 are provided and used.”

Approach Boundaries to Live Parts Picture From Practical Guide to Arc Flash Hazards

Approach Boundaries Flash Protection BoundaryFlash Protection Boundary –Linear distance at which no more than 2 nd degree burns possible from potential arc flash (typically 4 feet). See table (c) Limited Approach Boundary –Entered only by qualified persons or unqualified persons who have been advised and are escorted by a qualified person Restricted Approach Boundary –Entered only by qualified persons required to use shock protection techniques and P.P.E. Prohibited Approach Boundary –Enter only by qualified persons requiring same protection as if in direct contact with live part NFPA 70E-2004 Chapter 1, Sect

Shock Hazard Analysis NFPA 70E-2004 –Chapter 1, Section (A) Shock Hazard Analysis “Shock hazard analysis shall determine the voltage to which personnel will be exposed, boundary requirements, and the P.P.E. necessary in order to minimize the possibility of electric shock to personnel.” –What is Required? 1.Determine the Operating Voltage of the System 2.Determine Shock Protection Boundaries 3.Determine the Personal Protection Protective Equipment

Shock Hazard Analysis How to Comply with NFPA 70E: 1.Determine the Operating Voltage. 2.Determine the Three Shock Protection Boundaries by using Table (C) of NFPA 70E-2004 a.Limited Approach Boundary –10 ft for 480V for movable energized object –3 ft 6 in. for fixed energized object b.Restricted Approach Boundary 12 in. for 480V c.Prohibited Approach Boundary 1 in. for 480V

Shock Hazard Analysis How to Comply with NFPA 70E: Table (C)

Shock Hazard Analysis How to Comply with NFPA 70E –3. Determine Personal Protective Equipment a.Determine Risk Category from Table (C) (9) (a) on NFPA 70E-2004 b.Determine Specific PPE & Clothing from Table (C) (10) of NFPA 70E-2004

Shock Hazard Analysis Determining Risk Category from Table (C) (9) (a) on NFPA 70E-2004

Determining PPE from Table (C) (10) on NFPA 70E-2004

Table (C) (10) Notes

Flash Hazard Analysis NFPA, Ch 1, Sect : Flash Hazard Analysis. “A flash hazard analysis shall be done in order to protect personnel from the possibility of being injured by an arc flash. The analysis shall determine the Flash Protection Boundary and the personal protective equipment that people within the Flash Protection Boundary shall use.” How to comply with NFPA 70E for Flash Protection? 1.Determine the Flash Protection Boundary 2.Determine the incident energy exposure level 3.Determine the Protective Clothing and PPE

Flash Hazard How to Comply with NFPA 70E for Flash Protection: 1.Determine Flash Protection Boundary: Calculate using the I Short-Circuit Amperes & the clearing time for the overcurrent protection (See formula below and on page 25 of NFPA 70E-2004 OR default to four feet—600V or 300 kA cycles per (A) of NFPA 70E-2004) Flash Protection Boundary Formula (600 V or less) D C = [53 x MVA x t] 1/2 where Dc = Arc Flash Boundary (AFB) in feet MVA = Transformer capacity in MVA t = clearing time in seconds Second Degree Burn Threshold: 1.2 cal/cm 2

Defaulting to 4’ is easier than doing the Math… [Here the miracle happened...] At 600 V or less….

Flash Hazard Analysis 2. Determine the Incident Energy Level: Calculate incident energy exposure level for distance between worker’s face & chest from the potential arc source (18” typically) OR use 130.7(C)(9) & (10) Incident energy formula for arc in a cubic box: E MB = D A t A [0.0093F 2 – ] Where E MB = cal/cm 2 in 20 inch cubic box D A = distance from electrode in inches t A = clearing time F= I Short-Circuit Amperes

Flash Hazard Analysis 3. Determine the Proper PPE: Once the incident energy is determined, the PPE has to have a rating equal to or greater than the incident energy available. Determine Flash Protection Boundary using (A) Use Table (C) (9) (a) to determine the Hazard/Risk Category Select PPE from Table (C) (10) of NFPA 70E-2004.

Flash Hazard Analysis Example Task: An electrician is to remove the covers to measure the voltage on a panel board operating at 480 V. Solution: Table (C) (9): Hazard/Risk Category=2* (V-Rated Gloves & V-Rated Tools Required) Table (C) (10) Specifies the following: Untreated Natural Fiber T-Shirt & Undergarments FR (8 cal/cm 2 ) Long Sleeve Shirt and Pants Hard Hat Safety Glasses or Safety Goggles Arc-Rated Face Shield w/ Flash Hood Hearing Protection Leather Gloves Leather Work Shoes No Fabric Softener or Bleach

Common PPE Terms Incident Energy: Measurement of thermal energy at a specified distance for the arc (normally 18”). Energy is typically measured in cal/cm 2. Arc Thermal Performance Exposure Value (ATPV): The incident energy level (in cal/cm 2 ) that would cause the onset of a second-degree burn. V-rated: Tools and gloves tested for the line-to-line voltage at the area where the work is to be performed. Flame-Resistant or Flame-Retardant: A term referring to fabric and its ability to limit severity of burning. Break-open Threshold Energy (E BT ): The highest incident energy level which did not cause flame resistant (FR) fabric break-open and does not exceed second-degree burn criteria.

PPE Protection Ratings

Determining PPE by using NFPA 70E NFPA 70E Table 130.7(c)(9)(a) 1.Determine common work task from table that matches work to be performed. 2.Identify Hazard/Risk Category of task (0-4). 3.Refer to NFPA Table 130.7(c)(10): Protective Clothing and Personal Protective Equipment Matrix. 4.Read all applicable “Notes” that may apply. Note: Any task not covered in tables or exceed assumptions are required to have a Flash Hazard Analysis performed in accordance with NFPA 70E Review:

0 +

1 Or

+ 2

+ 2* Or +

+ 3 + OR: ++

+ 4 +

And now you know the rest of the story…

PPE Cautions Use only PPE with ratings equal to or higher than the incident energy level (cal/cm 2 Always properly clean and launder PPE prior to use (per manufacturer’s specifications) Inspect PPE and make necessary repairs to the manufacturer’s specifications prior to use Replace PPE after expected wear life Avoid fabric contamination from oils and other flammable materials It is recommended that PPE should not be used once it has been exposed to an arc condition.

Elimination/Substitution & Engineering Controls Substitute for hazardous materials/reduce energy or speed Machine guarding/sound enclosures/circuit breakers National Safety Council Hierarchy of Controls Warnings Signs/placards/alarms/back-up beepers/labels Training/Procedures Administrative Controls Lockout-Tagout/Job Hazard Analysis Rotation of workers P.P.E.

Other Protective Equipment: Insulated Tools 1. Insulated tools and equipment must be rated for the voltages on which they are used Insulated tools— designed and constructed for the environment and manner in which they are used.

Alerting Techniques 1. Physical barricades Signage Attendants –“If barricades and signage fail to provide sufficient warning and protection from electrical hazards, an attendant shall be stationed to warn and protect employees.”

NEC-Required Arc Flash Labeling

2002 NEC § Requires Arc Flash Labels

Regulations and Requirements for Working on Live equipment Federal OSHA, CAL-OSHA, NFPA

: Selection and use of work practices –(a) General. Safety-related work practices shall be employed to prevent electric shock or other injuries resulting from either direct or indirect contact, when work is performed near or on equipment or circuits which are or may be energized. The specific safety-related work practices shall be consistent with the nature and extent of the associated hazards

Safety-Related Work Practices Safeguards for personnel protection –(a) (2) (B) (ii): Protective shields, protective barriers, or insulating materials shall be used to protect each employee from shock, burns, or other electrically related injuries while that employee is working near exposed energized parts which might be accidentally contacted, or where dangerous electric heating or arcing might occur.

Proper Safety Procedures Save Lives

Response to an Electrical Accident Personnel who are trained to perform First-Aid/CPR should be identified and available when work near or on energized part is being performed

The first step must be to TURN OFF THE POWER Response to an Electrical Accident

Steps to Take if an Electrical Incident Occurs If power cannot be turned off, break victim’s contact with electricity

Steps to Take if an Electrical Incident Occurs Remove the immediate hazard: Turn off the power Remember speed is essential Extinguish flames Call for help (911) Begin First-Aid & CPR First Aid –Cool the burn with water –DO NOT attempt to remove burnt clothing –Elevate burned limbs –Handle the victim with care –Treat for shock Maintain body temperature Do not give anything by mouth

`

Any Questions?