ARC Flash Protective Clothing

8/16/2019 ARC Flash Protective Clothing

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A R C - F L A S H P R O T E C T I V E C L O T H I N G F O R N F P A 7


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Arc-Flash Protective Clothing FOR NFPA 70E – 1

NFPA 70E is the national consensus

standard for electrical safety in theworkplace.

The scope of this standard is to address safety-related workpractices for the practical safeguarding of employees relativeto the hazards associated with working around electricalenergy. It specifically covers those electrical work practicesperformed by electricians and maintenance workers withina facility.

Nearly all industries fall under the practices outlined inNFPA 70E. Manufacturing industries using high-voltageelectrical equipment, such as aerospace, automotive,food processing, pulp and paper, industrial equipment,electronics, pharmaceuticals, and many others, are allcovered by NFPA 70E. However, NFPA 70E does not coverelectrical work performed outside of the facility that is underthe exclusive control of an electric utility. This industry iscovered by the National Electrical Safety Code (NESC).

Many state OSHA agencies use NFPA 70E as their guidelinefor evaluating the protection of electrical workers. Thosecompanies not protecting their employees from electricarc-flash hazards as described by this standard are at riskfor potential fines should a safety inspection take place oran accident occur. So compliance with NFPA 70E not onlyprotects workers but reduces the risk of OSHA fines.

This informational guide will give you a brief overview of theNFPA 70E sections related to arc- flash protective clothingand other personal protective equipment (PPE).


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2 – Workrite Uniform Company, Inc.

Article 130 – Work Involving Electrical Hazards

This is the section within NFPA 70E that addresses theconditions under which PPE is required and the type andlevel of protection needed for various work conditions.

It starts by stating, “Energized electrical conductors andcircuit parts…shall be put into an electrically safe workcondition before an employee performs work…”With thatsaid, the standard goes on to state that“ energized workshall be permitted where the employer can demonstrate thatde-energizing introduces additional hazards or increasedrisk.” It also states that “energized work shall be permittedwhere the employer can demonstrate that the task to beperformed is infeasible in a de-energized state due toequipment design or operational limitations.”

PLUS: Equipment operating at less than 50 volts is not

required to be de-energized.

Hazard Assessment

In order to determine the proper type and protection level ofPPE, a hazard assessment must be performed. In addition,federal OSHA requires employers to conduct hazardassessments in accordance with 29 CFR 1910.132(d). If anarc-flash hazard is present, OSHA deems the employer to bein compliance if NFPA 70E is the basis of determining the

arc-flash protection boundary and the necessary PPE.

Section 130.5 Arc-Flash Risk Assessment

A critical piece of the hazard assessment is performing anarc-flash hazard analysis. This analysis is required in orderto establish the arc-flash boundary, the incident energy at

the working distance and the PPE that people within thearc-flash boundary shall use.

This section allows for the selection of the protectiveclothing and other PPE to be established by eitherperforming an incident energy analysis or by using thePPE tables established in the standard. You can determinethe PPE category by comparing the desired job withcommon tasks found in NFPA 70E table 130.7 (C)(15) (A) (b).Once the task has been identified on the table, one of fivePPE category numbers will be identified as appropriatefor that task. Each of these categories requires garments

with the minimum associated arc rating and other PPEto be worn.

NFPA 70E

Energized Component

Flash Boundary

Within the flash boundary, a personcould receive at least a second-degree

burn from an arc flash.

Fig. 1

ARC FLASH BOUNDARY =The distance at which theincident energy equals 1.2cal/cm². This is the energy

level that will generate asecond-degree burn onexposed skin.


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EquipmentPPE

Category

Arc-Flash

Boundary

Panelboards or other equipment rated 240V or below. Maximum of 25kA

short-circuit current available; maximum of 0.03 sec (two cycles) fault clearing time;

working distance 455 mm (18 in.).

1485 mm

(19 in.)

Panelboards or other equipment rated > 240V and up to 600V.

Parameters: Maximum of 25kA short-circuit current available; maximum of 0.03 sec

(two cycles) fault clearing time; working distance of 455 mm (18 in.).

2900 mm

(3 ft.)

Other 600 V class (277 V through 600 V, nominal) equipment.

Parameters: Maximum of 65 kA short-circuit current available; maximum

of 0.03 sec (two cycle) fault clearing time; minimum 18 in. working distance.

21.5m

(5 ft.)

Metal-clad switchgear, 1kV through 15 kV. Parameters: Maximum if 35 kV shirt-circuit

current available; maximum of up to 0.24 sec (15 cycles) fault clearing time; working

distance 910 mm (36 in.).

412m

(40 ft.)

Once the HRC number has been identified from the task table, the PPE table 130.7 (C)(16) (see page 4) shall be used to

determine the requirements for the specific protective clothing and other PPE based on that HRC number. HRC 1 and 2 are

typically standard work clothes that have been arc rated from between a minimum of 4 cal/cm² for HRC 1, and a minimum

of 8 cal/cm² for HRC 2. When the incident energy potential reaches 25 cal/cm², HRC 3 is required; at 40 cal/cm² and greater

HRC 4 garments are required.

70E Arc-Flash Hazard PPE Categories for Alternating Current (ac) Systems

Table 130.7 (C)(15)(A)(b)


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PPE

CategoryClothing & PPE Description

Minimum

Arc Rating

1

Arc-Rated Clothing: Arc-rated long-sleeve shirt and pants or arc-rated coverall,

arc-rated face shield or arc-flash suit hood, arc-rated jacket, parka, rainwear or hard

hat liner as needed

Protective Equipment: Hard hat, safety glasses or goggles, hearing protection,

leather gloves, leather footwear

4 cal/cm²

2

Arc-Rated Clothing: Arc-rated long-sleeve shirt and pants or arc-rated coverall, arc-

rated face shield and arc-rated balaclava or arc-flash suit hood, arc-rated jacket, parka,

rainwear or hard hat liner as needed



8 cal/cm²

3

Arc-Rated Clothing: Arc-rated long-sleeve shirt, arc-rated pants, arc-rated coverall,

arc-rated flash suit jacket, arc-rated flash suit pants, arc-rated flash suit hood, arc-rated

gloves, arc-rated jacket, parka, rainwear or hard hat liner as needed



25 cal/cm²

4

Arc-Rated Clothing: Arc-rated long-sleeve shirt, arc-rated pants, arc-rated coverall,

arc-rated flash suit jacket, arc-rated flash suit pants, arc-rated flash suit hood, arc-rated

gloves, arc-rated jacket, parka, rainwear or hard hat liner as needed



40 cal/cm²

70E Hazard/Risk Category Classification Table (Cont.)

Table 130.7 (C)(16)


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Section 130.7 Personal and Other ProtectiveEquipment

This is the section that provides specific requirements forthose employees working in areas where electrical hazardsare present. Those employees are required to be providedwith and use protective equipment designed for the specificpart of the body to be protected at the incident energy level,as established in the arc hazard analysis or as specified inthe HRC tables.

The specific parts of the body required to be protectedinclude:

Head, Face, Neck and Chin (Head Area) ProtectionNon-conductive head protection whenever there is a dangerfrom shock, contact burns or flying objects from electricalexplosions. The face, neck and chin shall be protected fromexposure to electric arcs or flashes and flying objects. Ifhairnets or beardnets are used, they must be arc-rated.

Eye ProtectionEye protection when there is a danger from electric arcs,flashes or flying objects.

Hearing ProtectionHearing protection whenever working within the arc-flashboundary.

Body Protection Arc-rated clothing whenever there is a possibility ofexposure to an electric arc flash above an incident energylevel of 1.2 cal/cm².

Hand and Arm Protection Hand and arm protection as appropriate for either shockand/or arc flash as detailed in other sections.

Factors in SelectionThe specific factors in the selection of protective clothingare stated as: “If arc-rated clothing is required, it shallcover associated parts of the body as well as all flammableapparel.” It goes on to state that “garments that are notarc-rated shall not be permitted to be used to increase thearc rating of a garment or of a clothing system.”

Layering, Coverage and FitGeneral non-melting, flammable fiber garments arepermitted to be used as under layers in conjunction witharc-rated garments for added protection. The arc rating ofthe system must be sufficient to prevent break-open of theinnermost arc-rated layer.

Outer Layers The outermost layer, such as jackets or rainwear, must bemade of arc-rated material.

Under Layers Meltable fibers such as acetate, nylon, polyester,polypropylene and spandex are not permitted in fabric undelayers (underwear) next to the skin.

CoverageClothing must cover potentially exposed areas as completelyas possible. Shirts and coverall sleeves shall be fastenedat the wrist, shirts shall be tucked into pants, and shirts,coveralls and jackets should be closed at the neck.

Fit

Tight-fitting clothing should be avoided. Loose-fittingclothing provides additional insulation because of air spaces

InterferenceThe garment should have the least interference with thetask but still provide the necessary protection.


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Simplified Choices with Two Clothing Sets

Though different clothing is specified for each arc-rating minimum, many companies simplify their needs by choosing justtwo sets of clothing for their people to handle all electrical tasks:

(a) A garment set with an arc rating of atleast 8 cal/cm² for the more routine tasksof PFE category 1 and 2

(b) A garment set with an arc rating of atleast 40 cal/cm² for more specializedtasks of PFE category 3 and 4

Standards on Protective Equipment

Table 130.7(C)(14) lists the various performance standards, to which the protective clothing and PPE needs to conform.

PPE Type Document Number Document Title

Apparel – Arc-Rated ASTM F1506

Standard Performance for Flame-Resistant and Arc-Rated Textile

Materials for Wearing Apparel for Use by Electrical Workers

Exposed to Momentary Electric Arc and Related Thermal

Hazards

Eye and Face – General ANSI/ASSE Z87.1Practice for Occupational and Educational Eye and Face

Protection

Face – Arc-Rated ASTM F2178 Standard Test Method for Determining the Arc Rating andStandard Specification for Face Protective Products

Gloves – Leather Protectors ASTM F696Standard Specification for Leather Protectors for Rubber

Insulating Gloves and Mittens

Gloves – Rubber Insulating ASTM D120 Standard Specification for Rubber Insulating Gloves

Head Protection – Hard Hat ANSI/ISEA Z89.1Personal Protection – Protective Headwear for Industrial

Workers

Rainwear – Arc-Rated ASTM F1891 Standard Specification for Arc- and Flame-Resistant Rainwear


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So What Role Can Arc-Rated Clothing Play?

Arc-rated clothing:

• Does not ignite or continue to burn

• Provides a protective barrier against the arc flash

• Insulates the wearer from heat

Why is this important?

• Most severe burns are caused by ignited clothing ratherthan by the original hazard

• Clothed areas can be burned more severely than skin thatis exposed directly to the arc flash, because the initialexposure is of a short duration while the burning clothingcontinues to apply heat to the skin until it either goes outor is removed

• The long-term cost of a single burn injury can exceedthe cost of an entire FR clothing program

• Rehabilitation for burn injuries can be extremely longand painful

Arc-rated clothing is worn as insurance. In the unlikely event of an arc flash, these garments:

• Minimize or reduce burn injury

• Increase chances of survival

Summary

Each year, more than 2,000 employees are admitted to burn centers with severe burns resulting from arc-flash accidents.

Manufacturing facility workers within the arc-flash boundary are at risk of being exposed to an arc-flash event while

performing common electrical work on energized parts or equipment. Because of that, being in compliance with the NFPA

70E safety standard not only protects those workers but reduces the risk of fines to the company should an accident occur.

Surviving a Burn Injury

20-29

100

75

50

25

0

25% Body Burn

50% Body Burn

75% Body Burn

% Survival

Age Groups

Burn Survival Rate

30-39 40-49 50-59


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Documents

ARC Flash Protective Clothing