Posts Tagged

flame resistant clothing

Arc Flash Training ArticlesBurn Up the MythBurning Questions

Question: Can we use metal snaps on shirts for NFPA 70E?  Our traditional shirts have snaps and we are wearing arc rated t-shirts for daily wear then putting on arc rated long sleeved shirts for energized work.  Answer:  Good question! This opens up how standards work and are often misinterpreted.  NFPA 70E

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Arc Flash/Shock SafetyElectric Utility IncidentsOverhead line incidents

According to the article this was probably an arc flash and they WERE wearing flame resistant (arc-rated) clothing.  Most likely these folks will live will little long terms effects.  When clothing doesn’t ignite workers are typically not hurt badly.  The NESC and OSHA 1910.269 apply here so they should be

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Arc Flash Training Articles

Perhaps the most significant change to the 2009 NFPA 70E is a redefinition of PPE hazard risk categories (HRCs). The principles determining a PPE system for each hazard risk level are now based on developing a clothing system meeting a specific tested cal/cm2 level and comprised completely of arc-rated materials.

The key to this approach is wearing the correct amount of arc-rated protection, not necessarily the exact pieces of clothing listed in the 70E tables. For example, if eight cal/cm2 of protection are required, you can wear an eight cal/cm² arc-rated shirt and pants, or a four cal/cm² arc-rated shirt and pants and a four cal/cm² arc-rated coverall; or an eight cal/cm² arc-rated coverall over cotton shirt and pants. See what we mean? It is the total level of arc-rated protection that matters – that and the absence of synthetic materials. You can wear one level of eight calories or two layers of four calories, or any combination equaling the total cal/cm2 necessary to protect you from severe burns if an arc flash occurs. This method applies to all hazard risk categories. The 25 cal/cm2 required for HRC 3 protection can be achieved by wearing a shirt and pants, coveralls, arc flash suit, or any combination of clothing that meets the required protection level. This change gives employers more leeway in developing a protective clothing system that meets the specific needs of their companies.

If you look at the requirements for HRC 2 in Table 130.7(C) (10), you see the following under clothing requirements:

FR Clothing, Minimum Arc Rating of 8

Arc-rated long-sleeve shirt

Arc-rated pants

Arc-rated coverall

Arc-rated face shield or arc flash suit hood

Arc-rated jacket, parka, or rainwear (as needed) *

Previously the standard required HRC 2 to include an eight cal/cm² shirt or an eight cal/cm² coverall or a 4 cal/cm² with a cotton t-shirt. The cotton t-shirt was mandated. Now, you choose any eight cal/cm² system be it one layer or more but the cotton t-shirt is no longer mandatory and unrated layers do not add to the protection levels in the HRC´s. Natural fiber clothing like cotton, wool and silk are still allowed but cannot add to the protection level because of the risk of ignition. If a company wants to use cotton for protection, they must rate the system with the cotton underneath and control the cotton layer to assure no ignition. This can be done using the ASTM F1959 arc test method.

While this new approach offers more options in choosing PPE clothing, a company cannot randomly choose, for example, a four cal/cm² arc-rated shirt and a four cal/cm² arc-rated t-shirt, deem it an eight cal/cm² system and issue the clothing to electrical workers. When layers are used, the total system must be tested to get the total arc rating. Why? Because the sum does not always equal the whole. Most often, testing proves the system provides greater protection than the sum of its individual parts. However, the opposite may hold true. Some systems protect better than others. Some are barely additive (i.e. 4 cal/cm² + 4 cal/cm² = 8 cal/cm² ) but other systems such as using a heavy layer over a light layer might allow second degree burns at little more than the outer layer´s protective level (i.e. 4 cal/cm² + 8 cal/cm² = 8.1 cal/cm²) but most systems multiply the protection (i.e. 4 cal/cm² + 4 cal/cm² = 20 cal/cm²) See NFPA 70E Standard for Electrical Safety in the Workplace, 2009 Edition, M.3-3.1.

If you want to use an HRC system of layers, you will find many of the larger clothing manufacturers have already tested their arc-rated clothing as a system. Some mixed systems have been tested by utilities and this data is available free of charge from at

*Additional PPE equipment is also required, such as hard hat and safety glasses, but left out of this list since we are only focusing on clothing.

By Vickie Frost, Hugh Hoagland & Bill Shinn

Vickie, Hugh and Bill are Sr. Partners in eHazard the leading electrical safety and arc flash training company.

Vickie Frost is a technical writer and has been involved in electrical safety for over 20 years.

Hugh Hoagland & Bill Shinn, are members of ASTM F18 and Hugh is taskforce chair of many arc test methods. Bill has over 40 years electrical safety experience and is a Professional Electrical Engineer, retired from Alcoa.

Hugh does most of the world´s electric arc flash testing on clothing and PPE and does regular research at the Kinectrics lab in Toronto. Hugh is owner of his testing company

They may be contacted at:

13113 Eastpoint Park Blvd.


Louisville, KY 40223

Office: 502-716-7073

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Arc Flash Training ArticlesOSHA Electrical Safety Interpretations

OSHA actually addressed logos for flame resistant clothing (arc rated clothing) related to arc flash in an interpretation letter.  This is interesting. They didn’t give specific guidance but indicated the employer is responsible. ASTM F1506 does not require logos to be flame resistant but in a non-mandatory Appendix X1.2.5 it

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OSHA Electrical Safety InterpretationsOSHA Issues

“OSHA’s policy for citing the general industry standard for personal protective equipment (PPE), 29 CFR 1910.132(a), for the failure to provide and use flame-resistant clothing (FRC) in oil and gas well drilling, servicing, and production-related operations. For the purpose of this memo, FRC includes both flame-resistant and fire retardant treated clothing. Clarification of the need to provide and use FRC during certain drilling, servicing, and production-related operations is necessary to resolve its inconsistent use among drilling contractors, well servicing contractors, and oil and gas companies that employ thousands of workers in these operations. OSHA inspection history and current information, including consensus standards, scientific evidence, and accident and injury data, indicate a potential for flash fires during certain well drilling, servicing, and production-related operations….

Citation Guidance for 29 CFR 1910.132(a)

Where appropriate, CSHOs shall cite 29 CFR 1910.132(a) for the failure to provide and ensure the use of FRC in oil and gas drilling, well servicing, or production-related operations when there is a potential for flash fire hazards as discussed below.

Drilling Operations
FRC is usually not needed during initial rig up and normal drilling operations prior to reaching active hydrocarbon zones, unless other activities warrant their use; e.g., fracing a previously drilled well while rigging a well in close proximity.

A potential for flash fire exists once active gas or hydrocarbon zones are reached. Appropriate FRC shall be worn by exposed employees working on the well site prior to drilling into identified gas or hydrocarbon zones. CSHOs should verify that employees are wearing FRC in advance of reaching such zones.

Appropriate FRC should also be worn when there is a history of fluid or gas kicks from underground producing zones.

Once FRC is identified for use as provided above, employees should wear appropriate FRC until the final casing is cemented and the well is effectively closed.

Well Servicing Operations
CSHOs shall determine whether FRC is provided and worn during well servicing or workover operations, such as:

Pulling wet string tubing
Snubbing tubing
Swabbing operations
Fracturing or perforating the well
Using bridge plugs or packers
Open hole work
Flow testing, blowing down or venting the well
Plugging an abandoned well
Flowback operations
Wireline operations
Any operation working with wellhead or wellbore under pressure

Production-Related Operations
In OSHA’s experience, the potential for flash fire also exists in production-related operations that fall outside of drilling and well servicing. CSHOs shall determine whether FRC is provided and worn during production-related operations, such as:

Equipment openings (e.g., line breaking or valve changes)
Transfer of hydrocarbons
Maintenance operations on production equipment
Hot work operations
Tank heating
Using open flame
Start-up operations”

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Arc Flash Training ArticlesInternational Arc Flash StandardsNew Safety Products

My new article on choosing arc flash PPE is unbiased and real helpful on getting the right things without all the industry hype.  We don’t sell the PPE but we do most of the arc flash testing at so you can count on our info to assist in need.

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Arc Flash Training ArticlesArc Flash/Shock Safety

This paper is feared by some because Tom is calling us to really understand the arc.  What the real outcome of the paper is that faceshields and arc rated rainwear may be better protection than we realized and textiles might not be quite as good as we thought BUT ignitable

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Arc Flash FinesOSHA Fines for Arc Flash IncidentOSHA Issues

This is an older story but a good one to see when OSHA started working to enforce more on electrical safety surrounding arc flash.  Up until 2000, OSHA really only addressed arc flash in electric utilities.  The 1994 law 29 CFR 1910.269 came out then and OSHA really started focusing

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Combustible Dust ExplosionsPublic Electrical Safety

In this excellent article interviewing Scott Margolin Imperial Sugar tells of their plan to use “FR” uniforms. They chose excellent uniforms by the way, BUT the photo on the cover has the female worker in a melting hairnet. Sad this one still hasn’t got out. The guys in the famous

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Arc Flash Training Articles

Hugh Hoagland’s new article on common PPE mistakes covers like melting rainwear that says it is flame resistant when it isn’t, failing to train workers and the issues that come up because of this. When following NFPA 70E companies must think things through to give the best PPE program that

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