the “other” hazard of electricity · an arc flash study labeling of electrical equipment that...

The “Other” Hazard of Electricity

Larren Elliott Ph.D. Lindsay Polic, CSP, REHS

Larren Elliott Ph.D.

EORM Electrical Safety Service Partner

45 years practical and hands-on industrial experience

Electrician

Trainer

Electrical Inspector’s Exam certified by the International Association of Electrical Inspectors (IAEI)

Lindsay Polic, CSP, REHS

Principal Consultant with EORM

12 years of EH&S experience, both consulting and industry

Comprehensive EH&S audits

Program development and training

Process Safety Management (PSM) and environmental Risk Management Plan (RMP) gap assessments

2

Presenters

© 2013 Environmental and Occupational Risk Management, Inc.

About EORM

3 © 2013 Environmental and Occupational Risk Management, Inc. EORM Confidential -- Not for Distribution

History • Founded in 1990 by Environmental,

Health and Safety (EHS) managers to offer comprehensive EHS management and technical consulting services to the high tech industry

• In late 90s, successfully diversified our client base into multiple regional and vertical markets across the US and beyond

Today • 100 employees supporting 350 customers from 5

regional offices in US; HQ in San Jose, CA • Multidisciplinary EHS and Sustainability consulting

team • Well-established partners allow for cost-effective

and highly responsive international support • ISO 14001 and OHSAS 18001 Certified

Key Service Areas

4 © 2013 Environmental and Occupational Risk Management, Inc. EORM Confidential -- Not for Distribution

Industrial Hygiene Safety

EHS and Sustainability Outsourcing/

Shared Services

Ergonomics Process Safety

EHS Auditing and Management

Systems

Environmental Compliance

Business Continuity Planning

Corporate Sustainability

What We’ll Uncover Today

Hazards and Risk Identification What We’ll Uncover Today What is an arc flash? What are the dangers of an arc flash? How can the hazards be calculated? How can the hazards be reduced? What are the typical PPE requirements? Questions and answers

© 2013 Environmental and Occupational Risk Management, Inc. 5

The Hazards of Electricity

The first hazard of electricity that most people think about is:

SHOCK


Typical Effects of Electricity on Adults

Current Results

<1 mA None

1 mA Perception threshold

1-3 mA Mild sensation

3-10 mA Painful sensation

10 mA Paralysis threshold of arms. Cannot release handgrip.

30 mA Respiratory paralysis (stoppage of breathing)

75 mA Fibrillation threshold. May produce a .5% uncoordinated heart action.

250 mA Fibrillation threshold. May produce a 99.5% uncoordinated heart action.

4 A Heart paralysis threshold. Heart stops for duration of current passage. For short shocks may restart on interruption of current.

>5 A Tissue burning. Usually not fatal unless vital organs are burned.

mA = 1/1,000 of an ampere


The Physiological Effects of Electric Shock


Body Resistance

500 Ω 500 Ω

500 Ω 500 Ω 100 Ω

I E

I R

ER

ER

PI

PI

EI

I R

P

RI

E P R

2

2

2

EP

2PE

PR

E = I R

E = 50 mA x 1100 Ω

E ≈ 50 Volts

9 © 2013 Environmental and Occupational Risk Management, Inc.

The Hazards of Electricity

The other hazard of electricity is

ARC


Arc Flash Defined

“A dangerous condition associated with the release of energy caused by an electric arc”

An arc is produced by the flow of electrical current through ionized air after an initial flashover or short circuit

Arc Flash can result from inserting a tool in the wrong place or dropping a tool into a circuit breaker or service area

Arc Flash can also result from an equipment failure Any of these conditions may cause a phase-to-ground and/or a

phase-to-phase electrical short circuit fault


Arcing Fault Events

The temperature of an arc is approximately 20,000oC (35,500oF)

That’s four times the temperature of the surface of our Sun!

If the temperature of your skin gets greater than 99oC (210oF) for more than a 1/10th of a second you will receive a severe burn – onset of a second degree burn

If your skin receives more than 5 joules/cm2 (1.2 cal/cm2) you will receive a severe burn

A candle flame produces around 4.2 joules/cm2 (1 cal/cm2)


Arc Flash Effects

Burns from intense heat

Trauma from blast pressure

Toxic gases from vaporized metal

Sprayed molten metal droplets

Hearing damage from sound pressure wave

Eye damage


Residential 120 Volt Breaker Failure

This is why you want to always wear a leather glove when opening or closing a breaker!

First degree burns © 2013 Environmental and Occupational Risk Management, Inc. 14

The result of plugging in a knowingly “bad” 220 Volt clothes dryer.

All fingers and thumbs of both hands had to be removed.


Hierarchy of Effective Hazard Control


Arc Flash Standards

Arc flash hazard studies have emerged as an engineering service centered around two primary national standards:

– NFPA 70E-12 “Standard for electrical Safety in the Workplace” and CSA Z462 -12 “Workplace Electrical Safety” recognize many different calculation methods to determine the hazards associated with an arc flash

– The primary method that is used by a majority of software vendors is IEEE 1584, “Guide for Performing Arc Flash Hazard Calculations,”

Once the arc hazard has been quantified then NFPA 70E and CSA Z462 can be used to determine the PPE requirements

International Council Directive 89/686/EEC in Article 100a requires that when related to Personal Protective Equipment, the measured value of hazard must match a measured value of protection. The IEC has yet to provide technical direction on arc hazard quantification


NFPA 70E – 2012 (9TH Edition)

First edition – 1979

Three chapters – Safety-Related Work

Practices – Safety-Related

Maintenance Requirements

– Safety Requirements for Special Equipment

16 Annexes


Elements of Arc Flash Safety

Defined responsibilities

Arc Flash Hazard Analysis – Calculation of the amount of arc flash hazard

Warning labels on equipment

Training

Personal protective equipment

Tools for safe work


“A workplace free from known and recognized hazards that could cause death or severe injury.”

Employer will provide: – PPE – Training – Labeling – Insulated tools – Lock out/tag out devices

Employee will: – Follow safe work practices – Use appropriate voltage rated

(insulated) tools – Wear PPE when required

Responsibilities


Elements of Arc Flash Safety

Determine the flash protection boundary – onset of a second degree burn (5 joules/cm2 or 1.2 cal/cm2)

Arc flash hazard and flash protection boundary varies with: – Type of equipment and configuration – Available short circuit fault current – Voltage – Predicted fault duration – protective devices upstream of the arcing fault and their settings

DC = (2.65 x MVAbf x t)½ Distance in feet for onset of a second

degree burn

Available fault current in amperes Time in seconds

fault current flows Applied nominal voltage


The hazards associated with arc flash must be predictable and when possible reduced through:

Engineering & Maintenance

Performance testing of breakers down to the point in the electrical system where there is no longer a hazard

A selective coordination study to determine proper over current protection device reaction time

An Arc Flash study

Labeling of electrical equipment that has the capacity to produce an arc (e.g., switchboards, panel boards, motor control centers) with appropriate arc flash labels that communicate the presence of a shock or arc flash hazard and that personal protective equipment is required to work within the documented flash protection boundary


Engineering Controls


Flash Protection Boundary

Linear distance from exposed live parts within which a person could receive second degree burns resulting from an arc flash


Administrative Controls – Relationships with Contractors

Host Employer must: – Inform contract employer of known hazards – Report observed contract employer-related violations

Contract Employer Responsibilities: – Ensure that each employee is instructed in the hazards and follows the standards

and work rules required by the host employer – Advise host employer of unique or unanticipated hazards not reported by host

employer – Measures the contractor took to correct any violations reported by host employer

This meeting must be documented


Administrative Controls – Training Requirements

Document that Qualified Persons have demonstrated that they are qualified to work on the specific equipment

Employees exposed to shock hazards and first responders must be trained in: – Methods of release – First aid including annual certification in CPR and AED use

Document conformance assessment that each employee is complying with safety-related work practices required by NFPA 70E


Administrative Controls – LOTO and other Job Requirements

Individual Control has been eliminated from NFPA 70E.

Verification of deenergization by phase-to-ground and phase to phase

Employer must provide up-to-date drawings, diagrams, or identification tags

Documented pre-job briefings

Documented risk assessment procedure that includes hazard analysis, risk estimation, and risk evaluation procedures

An Energized Electrical Repair Work procedure and permit


Labeling

Switchboards, panel boards, industrial controls, etc. that require examination, adjustment, or maintenance while energized shall be labeled.

Labels shall be designed to warn of potential arc flash hazards


Arc/Flash Protection

Arc/Flash Suits

Arc/Flash Hood

Hard Hat Liners Face Shield

Balaclava Beard Cover & Hair Net


Typical Protective Clothing

Hazard/Risk Category Clothing Description

Required Minimum Clothing Arc Rating

[J/cm2 (cal/cm2)]

0 Non-melting, flammable material with fabric weight of at least 4.5 oz/yd2

Not applicable

1 Arc-rated shirt + pants or Arc-rated coveralls 16.74 (4)

2 Arc-rated shirt + pants or Arc-rated coveralls 33.47 (8)

3 Arc-rated flash suit and hood or a tested layered system meeting the required minimum rating.

104.6 (25)

4 Arc-rated flash suit and hood 167.36 (40)


Typical PPE Requirements

Hazard/Risk Category

Eye protection, ear canal inserts, long sleeve shirt and

pants

Arc rated clothing

Face & Head Protection

Flash Suit Hood

0 1 2 3 4


HRC-1 HRC-2

HRC-3 HRC-4

Hands must have more AR protection

≥10 cal/cm2


Cleanroom AR Clothing

As well as Cintas and Oberon


ISO 14644-1 cleanroom standards

Class

maximum particles/m³ FED STD 209E equivalent ≥0.1 µm ≥0.2 µm ≥0.3 µm ≥0.5 µm ≥1 µm ≥5 µm

ISO 1 10 2.37 1.02 0.35 0.083 0.0029 ISO 2 100 23.7 10.2 3.5 0.83 0.029 ISO 3 1,000 237 102 35 8.3 0.29 Class 1

ISO 4 10,000 2,370 1,020 352 83 2.9 Class 10

ISO 5 100,000 23,700 10,200 3,520 832 29 Class 100

ISO 6 1.0×106 237,000 102,000 35,200 8,320 293 Class 1,000

ISO 7 1.0×107 2.37×106 1,020,000 352,000 83,200 2,930 Class 10,000

ISO 8 1.0×108 2.37×107 1.02×107 3,520,000 832,000 29,300 Class 100,000

ISO 9 1.0×109 2.37×108 1.02×108 35,200,000 8,320,000 293,000 Room air


Layering of arc-rated clothing can increase rating only when tested as a multilayer test sample


Voltage Rated Insulated Tools

When repair work must be done on energized equipment, tools must meet the ASTM F 1505 standard


Thank you!


Contact Lindsay Polic with any questions – Lindsay Polic

Principal Consultant 949.420.0670 [email protected]

View the recorded webinar at www.eorm.com/download/arcflash/

See www.eorm.com for more information

mailto:[email protected]

http://www.eorm.com/download/arcflash/

http://www.eorm.com/

the “other” hazard of electricity · an arc flash study labeling of electrical equipment that...

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