Personal Protective Equipment For Electrical Hazards

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Personal Protective Equipment For Electrical Hazards

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In February 1972, OSHA incorporated the 1971 edition of the National Fire Protection Association's (NFPA) National Electrical Code (NEC), NFPA 70-1971

On January 16, 1981, OSHA revised its Electrical standard with Part I of National Fire Protection Association's (NFPA) 70E - 1979

On August 13, 2007, OSHA revised its Electrical standard to reference National Fire Protection Association's (NFPA) 70E - 2000

What’s New

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Arc Flash Event

A dangerous release of energy created by an electrical fault

 Release will contain:

 Thermal energy

 Acoustical energy

 Pressure wave

 Debris

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Arc Flash Intensity

Variables that effect the size and energy of an electric arc flash:

 Amperage

 Voltage

 Arc Gap

 Closure time

 Distance away from arc

 3 phase v single phase

 Confined space

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Arc Energy Basics

 Exposure energy expressed in cal/cm2

 ½ to 1 cal/cm² = hottest part of lighter in 1 sec

 1-2 calorie exposure will cause second degree burn on human skin

 Typical non-FR workwear can ignite @4-5cals

 Arcs typically release 5-30 cals - energies of 30-60 cals are not uncommon

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Arc Flash Events

 Can reach 35,000 F

 Fatal burns >10 feet

 Majority of hospital

admissions are arc flash burns, not shock

 30,000 arcs and 7000 burn injuries per year

 Over 2000 people admitted to burn centers yearly with severe arc flash burns

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Why is FR Needed?

• Most severe burn energies and fatalities are caused by non-

flame resistant clothing igniting and continuing to burn

• Flame resistant clothing will self- extinguish, thus limiting the

injury

• Body area under non-FR

clothing is often burned more severely than exposed skin

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What Is a Burn?

A chemical process which progressively injures skin; severity relates to depth

 1^st : redness, pain – not permanent

 2^nd: blistering – skin will regenerate

 3^rd: total skin depth destroyed. Will not regenerate – requires grafting

 4^th : Underlying muscle damaged

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Burn Survival

 Burn percentage, more than severity, predicts survival because skin is infection barrier

 2^nd and 3^rd degree break skin, providing an infection pathway

 Most hospital deaths 2-4 weeks post-exposure are infection

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Flash Protection Boundary (outer boundary): The flash boundary is the farthest established boundary from the energy source. If an arc flash occurred, this boundary is

where an employee would be exposed to a curable second degree burn (1.2 calories/cm²)

Flash Protection Boundary

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Prohibited Approach (inner boundary): A distance from an

exposed part which is considered the same as making contact with the live part.

Prohibited Approach Boundary

“Working On Live Parts”

Occurs when coming in contact with live parts, including test equipment, body, PPE, tools etc. . .

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Arc Energy vs Distance

Energy goes up dramatically as distance from arc drops:

EXAMPLE: 22,000A, 480V, 6 cycles:

24” 18” 15” 12” 10”

2.7 cal. 3.2 cal. 7.5 cal. 12.2 cal. 18 cal.

How close are you to the arc?

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Employer must develop and enforce safety-related work practices to prevent electric shock or other injuries resulting from either direct or indirect electrical contacts.

These safety related work practices could include:

• Energized Electrical Work Permit

• Pre-work Job Briefing

• Personal Protective Equipment

• Insulated Tools

• Written Safety Program

• Qualified Person Training

• Flash Hazard Labeling

Hot Work Requirements

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Flash Protection Labeling

Arc Flash Hazard labeling must be posted which identifies:

• Approach boundaries

• PPE required

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NFPA Tables: Refer to NFPA 70E – 2000 Table 3-3.9.1 or Table 130.7(C)99)(a) NFPA 70E – 2004.

Pro: Easiest and quickest method

Con: Provides the least amount of accuracy. Limited tasks are covered in tables

How to Determine Boundaries

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Formula Method: NFPA 70 E and IEEE Standard 1584 provides formulas that can be used to accurately determine the

approach boundaries.

Pro: More accurate and all inclusive than NFPA tables

Con: Is time consuming, requires an engineer level of expertise and is subject to human error.

How to Determine Boundaries

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Approach Calculator: IEEE and others have provided a

spreadsheet based calculator to assist in determining approach boundaries.

Pro: Quicker than formula method

Con: Still requires detailed information about the equipment and circuit often requiring the use of an electrical engineer.

How to Determine Boundaries

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Software:There exists on the market various software products that can simplify and expedite the approach boundary calculations.

Pro: Creates one-line diagrams and arc flash labels based on data entered

Con: Cost and equipment / circuit knowledge is still required often requiring an engineer.

How to Determine Boundaries

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What is Flame Resistant Clothing?

• Clothing made from fabrics that self-extinguish

• Fabrics may be natural or synthetic

• Designed to limit (not eliminate) burn injury

• Survival, extent of injury, recovery time and quality of life are all dependent on FRC performance

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Engineered Flame Resistant Fabrics

• Natural fibers

• Synthetic fibers

• Natural / synthetic blends

NOTE: Flame resistance must be durable to launderings, wear, the environment, etc. for the service life of the

garment

Look for proven products!

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New World of FRC

• FRC used to be perceived as ugly, uncomfortable, expensive, scratchy, hot and not breathable

• Major shift last 3-5 years to lighter, softer more

breathable fabrics and to styles virtually identical to

“street clothing”

• Examples include Nomex/Rayon blends, Indura &

UltraSoft® knits, fleeces, denims.

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Confused by the selection process?

National trend is single layer HRC 2 daily wear and HRC 4 flash gear

Don’t let confusion delay your PPE selection!

The 70E Solution

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Proper Use

• FRC should be appropriate to hazard

• Always the outermost layer

• Worn correctly; zipped, buttoned, etc

• All natural, non-melting undergarments

• Clean, no flammable contaminants

• Repaired correctly and removed from service when needed