NFPA 70E Electrical Safety in the Workplace KTR Associates Joseph - - PowerPoint PPT Presentation

NFPA 70E

Electrical Safety in the Workplace KTR Associates

Engineering Solutions

Joseph Deane, PE

Goal for Today

Better understanding of NFPA 70E Raise the awareness of Electrical Hazards Why the sudden focus What one must do to become “70E”

compliant

Topics To Be Discussed

Define Electrical Hazards Safety Numbers Industry Standards/Government Regulations What is an Arc Flash? Sample Arc Flash Study PPE Requirements

Why do we need Electrical Safety?

Provide a safe work environment Reduce injuries Comply with regulations Reduce liability Reduce operating costs

What are the Electric Hazards?

Shock Arc Flash Arc Blast

Terms and Definitions

• Electric Shock (Contact):

Occurs when electricity (electric current) passes through the human body. Electric current passing through the chest area may result in death.

Terms and Definitions

Arc Flash: Short circuit through air; defined

as the rapid release of energy due to an arcing fault between two phase conductors (such as bus bar) or neutral or ground.

Arc Blast: Heating of the air and

vaporization of metal creates a pressure wave than can damage hearing and other injuries. Flying metal parts are a hazard.

Terms and Definitions

I ncident Energy: Energy dissipated during

an arc fault, or arc flash event. Measured in cal/cm2 .

Arc Thermal Performance Value (ATPV):

Minimum energy causing the predicted onset

• f second degree burns. A second degree

burn is 1.2 cal/cm2 .

Why the Recent Focus?

NFPA 70E standard now recognizes Arc Flash as a serious consequence and requires a Flash Hazard analysis be performed on facilities. OSHA has updated its Electrical Safety Procedures for the first time in 25 years. Effective date of OSHA’s updated regulations is August 13, 2007

Electrical Statistics

At least one person a day is electrocuted in the workplace everyday

Over half of the deaths are from working “live”

electrical circuits less than 600 volts.

Average of 4000 non-disabling and 3600 disabling electrical injuries occur in the US.

Electrocutions by Year

(Construction Safety Council)

474 440 480 486 395 544 664 100 200 300 400 500 600 700 1992 1994 1996 1998 # Electrocutions

Electrical Statistics

Five to 10 arc flash explosions occur in electrical equipment every day in the US. Fourth leading cause of occupational fatalities. Over 2000 workers are admitted to burn centers each year.

Burn Costs

Average burn case costs $12 to $20 Million Average hospital burn unit costs $400K per month Average hospital burn unit stay 3 months

Electrical Statistics

General Industry

One fatality per 300 recordable injuries.

Electrical Industry

One fatality per 10 recordable injuries.

Electrician Survey

97% had experienced an electrical shock. 26% had witnessed an injury. 58% were exposed to the possibility of an injury every day.

Facts on Electrical Incidents

80% of electrically related accidents and fatalities among Qualified Workers are caused by Arc Flash. 80% of electrically related accidents and fatalities among Unqualified Workers are caused by Electrocutions. Age 34 is the median age for someone killed working around electricity.

OSHA & NFPA 70E

OSHA was created in 1969. It incorporated the National Electric Code (NFPA 70 standard 1971) into its electrical standard. NFPA 70E Standard was created at the request of OSHA in 1979 to recognize the difference between design and workplace safety.

NFPA 70 (NEC) applies to installations (design). NFPA 70E addresses workplace safety.

OSHA Regulations

OSHA bases its electrical safety mandates on:

CFR 1910 Subpart S (General Industry) CFR 1926 Subpart K (Construction)

OSHA recognizes NEC and NFPA 70E as an industry standards.

OSHA Regulations

OSHA requires companies to follow its regulations and will cite companies for non-compliance under the General Duty Clause:

which states, “each employer shall furnish

to each of its employees a place of employment that is free from recognized hazards that are likely to cause death or serious physical harm.”

OSHA Regulations

OSHA is also citing companies for the following:

29 CFR 1910.335 (a)(1)(i): requires the

use of protective equipment when working where a potential electrical hazard exists.

29 CFR 1910.132 (d)(1): requires an

employer assessment of all workplace hazards and the use of personal protective equipment.

Who is the NFPA?

The National Fire Protection Association (NFPA) develops, publishes, and disseminates more than 300 consensus codes and standards intended to minimize the possibility and effects of fire and other risks. Virtually every building, process, service, design, and installation in society is affected by the NFPA documentation (Ex. the National Electric Code…NFPA 70).

National Electric Code (NFPA 70)

Utilized for design and installation of electric facilities

Wiring and Protection Wiring Methods and Material Equipment for General Use Special Equipment and Conditions

Intent of NFPA 70E

Objective is to minimize exposure to electrical hazards for personnel working around

• electricity. This includes:

Electricians Mechanics HVAC technicians Painters Plumbers Carpenters Production Workers

Intent of NFPA 70E

Define Safe Work Practices to avoid injury. Define the requirements for an Electrical Safety Program. Define the requirements for Training Define the requirements for PPE Applies to all types of employers and facilities, including employees, contractors, and construction workplaces.

NFPA 70E Electrical Safety Standard in the Workplace

Chapter 1 – Safety Related Work Practices Chapter 2 – Safety Related Maintenance Requirements Chapter 3 – Safety Requirements for Special Equipment Chapter 4 – NEC Related Installation Material

NFPA 70E covers…

Public and private buildings Carnivals Industrial Substations Any installation of electrical equipment to the supply of electricity

NFPA 70E does not cover…

Utilities Ships Mines Railways Communication equipment under control of communication utilities

NFPA 70E Chapter 1

Article 110 – Provides General Requirements

Responsibility Electrical Hazard Analysis Training Requirements Electrical Safety Program

Article 120 – Emphasizes Working De- energized & Describes the Work Practices Article 130 – Provides Requirements for Working On or Near Electrical Components

Chapter 1 Responsibility

Employers are responsible for providing work practices and procedures. Employees are responsible for implementing them.

Chapter 1 Multiemployer Relationship

Recognizes that more than one employer may be responsible for hazardous conditions on a worksite. Outside contractors are contractually

• bligated to the onsite employer.

Both employers must share their Electrical Safety Programs with each

• ther.

Chapter 1 Multiemployer Relationship

Onsite employers and outside contractors shall inform each other:

Of existing hazards PPE requirements Safe work practice procedures Emergency procedures

Coordination should include a meeting and documentation

Chapter 1 Electrical Safety Program

What needs to be in it? Scope Philosophy Principles Responsibilities Safety Procedures

Chapter 1 Electrical Safety Program

PPE Requirements Controls Training Requirements Auditing Other?

Chapter 1 Training Requirements

Trained to understand the specific risks associated with electric energy. Trained on safe work practices and procedures. Trained on emergency procedures. Training may be both classroom and on the job.

Training Session

• Misc. Real World Examples

Refeeding Panels (What needs to be

checked?)

Transformer Connections (Why they are

important)

Types of Grounding Systems Explain how voltage is a difference in

potential

Chapter 1 Electrical Hazard Analysis

Requires an electrical hazard analysis, which is a study of a worker’s potential exposure to:

Shock Arc Flash/Blast

It determines the appropriate levels of Personal Protective Equipment (PPE) and work practices.

Electric Shock

The original purpose of NFPA 70E Determine the voltage to which personnel will be exposed. Boundary Requirements PPE Requirements

Exposure to Shock

Requires exposure to a difference of potential The National Electric Code reduces this risk under normal conditions. NFPA 70E reduces the risk under abnormal conditions

NEC Protects - Normal Conditions

70E Protects - Abnormal Condition

Effects of Electric Current on the Human Body

Amps < 1 mA Barely perceptible 5 - 10 mA Tingling sensation (annoying) 10 - 20 mA “Let Go” threshold (discomfort) 20 – 50 mA Painful, cannot “Let Go” 50 - 100 mA Ventricular fibrillation Amps > 100 mA Cardiac arrest

Electric current greater than the “Let Go” threshold ( current > 20 mA) contracts the human body’s muscles. Individuals unable to “Let Go” an energized line face life threatening damage to their bodies. If this current level continues for an extended period of time, respiratory paralysis is

• possible. Ventricular fibrillation (uneven

pumping of the heart) causes death to lack of

• xygen to the brain.

Effects of Electric Current on the Human Body

Arc Flash/Blast

Electrical Arc between Conductors

Intense Light Molten Metal Pressure Wave Sound Wave Shrapnel Hot Air Rapid Expansion

Dangers of Arc Flash

Arcs in enclosures, such as MCCs and switchgear, magnify a blast outward as energy is transmitted to the open side of the enclosure. Fatal Burns (Molten metal at high speed pressure). Falls from ladders (Blast pressure waves). Hearing loss from sound blast.

Causes of Arc Flash

Contamination

Dust, Dirt or Vapor Corrosion Moisture Ingress

Dropping tools or equipment Insulation Breakdown/Aging Narrow Gaps

NFPA 70E Arc Flash Hazard Analysis

A flash hazard analysis shall be done for two purposes:

Determine the arc flash protection boundary. Determine the proper PPE (rating of flame

retardant clothing).

The Flash Protection Boundary is the approach limit from which a person could receive a second degree burn if an arc flash

• ccurs.

Sample Arc Flash Study

How do you do an Arc Flash Study? Results of an Arc Flash Study

IEEE 1584 Standard – Guide for Performing Arc Flash Hazard Calculations

Performing the Arc Flash Study

IEEE 1584 Standard – Guide for Performing Arc Flash Hazard Calculations

Nine Step Process

Collect system and installation data Determine system mode of operation Determine bolted fault currents Determine arc fault currents Find protective device characteristics and

arc duration

IEEE 1584 Standard – Guide for Performing Arc Flash Hazard Calculations

Nine Step Process (continued)

Document system voltages and equipment

class

Select working distances Calculate the incident energy Calculate the Flash Protection Boundary

From this info, select the proper PPE

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Purpose of Safety Related Work Practices (Article 120)

A set of rules that ensure an Electrically Safe Work Condition. De-energizing is safest work condition. Protect employees from:

Shock Arc Flash burns Arc Blast injuries

Steps to Create an Electrically Safe Work Condition (De-energized state)

Check drawings and identify all possible sources Interrupt load current and open disconnects Visually verify opening of contacts where possible Apply lockout/tagout devices according to policy Test voltage and verify operation of tester Apply grounds where necessary

Working on or near energized circuits (Article 130)

Why work on energized circuits?

Examples of working on energized equipment

Startup or troubleshooting Life Support systems Emergency systems Ventilation systems for hazardous locations

Examples of working on energized equipment

Infeasibility due to equipment design or

• perational limitations

Circuits that are part of integral process.

NFPA 70E Requirements for Working on or Near Live Parts

Complete Energized Electrical Work Permit Perform Hazard/Risk Analysis Select PPE Ensure task specific training Conduct a job briefing

Energized Electrical Work Permit

Requires written authorization Requires the worker to:

Identify and understand the hazards Be a qualified person Wear proper PPE Restrict access to unqualified persons Complete a job briefing

No Permit Required When…

Testing (voltage, current, phasing) Troubleshooting Circuit Identification

Approach Distances to Exposed Live Parts

PPE Requirements

Protect against shock and burns Designed to protect specific areas of the body:

Head, face, neck Ear protection Eye protection Body protection Hand and arm protection Foot and leg protection

Flash Protection Boundary & PPE

When working within the flash protection boundary, PPE must be worn. PPE is determined by the level of incident energy exposure.

Personal Protective Equipment (PPE)

Flash Hazard Risk Category Range of Calculated incident energy

• Min. PPE Rating

Clothing Required

0 to 1.2 cal/cm2 N/A Untreated cotton 1 1.2+ to 4 cal/cm2 4 cal/cm2 FR shirt and pants 2 4+ to 8 cal/cm2 8 cal/cm2 Cotton underwear plus FR shirt and pants 3 8+ to 25 cal/cm2 25 cal/cm2 Cotton underwear plus FR shirt and pants plus FR coveralls 4 25+ to 40 cal/cm2 40 cal/cm2 Cotton underwear plus FR shirt, pants, plus multilayer layer flash suit

Personal Protective Equipment (PPE)

Category 0 (Min. PPE Arc Rating N/A)

Untreated Cotton Safety Glasses

Category 1 (Min. PPE Arc Rating 4)

Long Sleeve FR Shirt & Pants Hard Hat Safety Glasses Leather Gloves & Shoes

Personal Protective Equipment (PPE)

Category 2 (Min. PPE Arc Rating 8)

Cotton Underwear FR Shirt & Pants Arc Rated Face Shield Safety Glasses Hearing Protection Leather Gloves & Shoes

Category 3 (Min. PPE Arc Rating 25)

Same as Cat 2 but include FR coveralls & Flash

Suit Hood

Personal Protective Equipment (PPE)

Category 4 (Min. PPE Arc Rating 40)

Cotton Underwear FR Shirt & Pants Full Flash Suit & Hood Hearing Protection Leather Gloves & Shoes

Labeling

NEC Article 110.16 requires arc flash labeling in electrical enclosures that might be maintained and accessed while energized.

Switchboards, panelboards, industrial control panels, MCCs, etc.

Arc Flash Labeling

Warning Label Examples

Recent Example of Arc Flash Incident

Electrician using multimeter shorted out resulting in three phase arc flash. Gloves and radiological PPE were melted and he suffered minor burns. Test equipment defective (CEN-TECH Digital Multimeter). No certification from a national testing laboratory.

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Sample Electrical Power Design

• Maintenance Mode

Switch (utilizing Microprocessor- based Protective Relays Alternate Settings)

• Control cabinet

containing switches to close breakers

What must I do to become NFPA 70E compliant?

Conduct an Arc Flash hazard analysis. Provide labeling on electrical equipment per NEC article 110.16 “Flash Protection”. Document your Electrical Safety Program. Provide training to your employees. Provide the proper tools and PPE for job tasks employee would be performing.

Other Issues to Think About

Determine Qualified vs Un-Qualified Who’s permitted to reset CBs? Anyone? Which methodology should I use for calculating incident energy?

NPFA 70E IEEE 1584

Energized Work Permit…when do I need this? Circuit Breaker Interrupting Ratings When do I apply OSHA 1910.269?

Don’t Learn Safety by Accident

KTR Associates

Don’t Learn Safety by Accident

Stop ! Think ! Then Act ! NFPA 70E is your guide for Electrical Safety in the Workplace

Questions

Thank-you for your interest!