Arming your crew with the appropriate FR gear is a feat in itself. Navigating the ever-changing sea of standards? Now that’s another beast entirely. Bulwark is here to help you choose the right FR program by ensuring you have a thorough grasp on the standards and what they mean for you—and your crew.
When the National Fire Protection Association (NFPA) introduced the term “Arc-Rated” or “AR” in its 2012 revision to NFPA 70E, it was a bit of a head-scratcher. The question on every safety manager’s mind was: what’s the difference between FR and AR? According to Bulwark’s Technical Training Manager, Derek Sang, the most basic and important thing to know when it comes to FR and AR is that all arc-rated clothing is flame resistant, but not all flame resistant clothing is arc-rated.
For a piece of clothing to be considered flame resistant, the fabric used to make the garment must withstand ignition and/or rapidly self-extinguish in order to protect the wearer from the dangers of flash fire, arc flash, molten metals and other hazards. In the event of a flash fire or arc flash, the FR PPE worn must resist catching fire, melting, and continuing to burn after the initial flash to act as a barrier between the wearer and the hazard.
The fabric used to create arc-rated clothing is subject to additional tests, above and beyond fabric labeled simply “FR.” Primarily, it is exposed to a series of arc flashes to determine how much energy the fabric is able to block before it would likely cause the wearer to obtain a 2nd degree burn, 50% of the time. The result of this test, expressed in calories, is known as the Arc Thermal Performance Value (ATPV).
Current standards for arc flash protection, detailed by NFPA 70E, state that all PPE clothing must also be flame resistant to qualify for an arc rating. In other words: all AR clothing is FR, but not all FR clothing is AR. This is because, based on the results of the series of tests outlined above, equipment rated FR may not always provide the adequate level of protection for workers who are at risk of encountering arc flashes. These employees—general industry electricians (70E)— must wear the appropriate level of AR clothing for the hazard, in order to reduce their risk of serious injury or death caused by an arc flash.
What is ATPV, and how is it used in your hazard assessment?
Put simply, ATPV—Arc Thermal Performance Value—is the most commonly reported test result of the effectiveness of FR clothing. It measures the amount of incident energy that your FR garment can protect you from before the onset of a 2nd degree burn. And the FR garments in your safety program must meet or exceed the Incident Energy required based on your hazard assessment. But it’s a bit more complicated than that.
To better understand ATPV, let’s start with an overview of two main concepts: The Stoll Curve and Arc Ratings.
The Stoll Curve
The Stoll Curve is the predictive model used to measure the probability of burn injury. It quantifies the heat levels and exposure times that result in a second-degree burn, including high temperature exposure for a short time and low temperature exposure for a much longer duration.
An arc rating is the protection level afforded by an FR fabric when exposed to an electric arc. The arc rating of a fabric is determined by exposing the fabric to a staged electrical arc. In real life, arc behavior can be unpredictable, so the testing requires samples be exposed to a “controlled” arc utilizing the ASTM 1959 standard.
That brings us to ATPV (Arc Thermal Performance Value), which is a type of arc rating. The ATPV of an FR garment indicates that you have a 50% chance of the onset of a 2nd degree burn if exposed to an electric arc with the same calories of incident energy. The fabric will usually not break open unless exposed to incident energy levels higher than the arc rating.
So why is ATPV important? Think about it this way:
Let’s go back to what ATPV measures:
The amount of incident energy that your FR garment can protect you from before the onset of a 2nd degree burn.
Why is that important?
• By definition, second-degree burns cause a blistering, blisters can break the skin (that’s why the test is designed around 2nd degree burns).
•One of the pathways to infection is broken skin.
• One of the causes of death in burn victims is infection.
When you think about it that way, matching the ATPV of the FR garments in your safety program to the value required by your hazard assessment is not just a matter of meeting the standards. For your guys, it can be the only thing that stands between them and a potentially life-threatening burn hazard.
To learn more about ATPV and Arc Ratings, download our whitepaper: Understanding Arc Ratings
You know you need to be wearing FR. And you know your FR clothing has to meet—or better yet, exceed—your required ATPV. A layered FR system is one great way to ensure you’re protected and keep you comfortable.
But FR layering can get tricky. It’s not as simple as adding up the arc ratings of each layer. For instance, the Bulwark Long Sleeve FR Two-Tone Base Layer- EXCEL FR® on its own carries an ATPV of 6.4 calories/cm². And the Deluxe Coverall – CoolTouch® 2 – 7 oz. carries an ATPV of 9.0 calories/cm² (KH). However, when combined as a layered FR system, the two garments have a layered arc rating of 21 calories/cm2 and a layered CAT rating of 2. As you can see, that’s significantly higher than the total ATPV if you simply combined the two garments’ arc ratings. This is the result of a number of factors, one of which is the additional layer of air between the layers that creates added insulation.
That brings us to another crucial aspect of FR layering, and one that causes a lot of confusion among safety professionals. Do the standards permit you to layer non-FR undergarments beneath your FR garments?
The answer, in short, is yes, if it is beneath the outer FR layer:
According to NFPA® 70E section 130.7 (C) (12) (a), non-melting flammable garments (i.e., non-FR) are permitted to be worn under FR garments for added protection.
In fact, as we demonstrated above, putting an extra layer of fabric between your skin and your outer FR layers can provide an added level of protection—even if the garment is not FR. It has the further benefit of absorbing perspiration to keep you drier and more comfortable in warmer months, while insulating you against the elements in cold weather. However, that layer—and the added protection it affords the wearer—will not count toward achieving the required arc rating of the complete FR layered system. Any protection it provides is considered above and beyond the ATPV already met by the FR garments.
It is also important to note that meltable fibers such as acetate, nylon, polyester, polypropylene, and spandex cannot be used in the layer closest to your skin. Because in the event of a flash fire or electric arc, some heat will inevitably pass through the outer layer of FR and cause a T-shirt to melt if it is made from synthetic materials like those fabrics mentioned above. The melting of these materials can significantly increase the burn injury. Undergarments made with natural fibers are permitted, as they will not add to the injury. However, that is assuming there is no break open of the outer layer and the outer layer is worn correctly (tucked-in), both of these scenarios could allow for the base layer made with natural fibers to ignite.
As such, when it comes to layering your FR, the best solution to maximize both safety and comfort is to opt for an FR base layer, like those offered by Bulwark. Our FR base layers are designed to wick moisture and keep you comfortable, while increasing your overall protection by eliminating the threat of ignition. And, since these FR base layers are arc rated, they can contribute to your overall layered system arc rating. Meaning you can achieve or even exceed your required protection level, often with a combination of lighter weight FR fabric.
To simplify the FR layering process, we worked with our very own FR experts to design the Bulwark Arc Rating Calculator—an online tool that allows you to quickly and simply determine the total system arc rating for over 400 combinations of Bulwark FR garments.
AR, FR, ATPV, OSHA. The list goes on and on. If there’s one thing that’s true about FR safety, it’s that there are a lot of terms to memorize. It’s not always easy to keep the various words and acronyms straight, but when it comes to building and implementing an effective safety program, knowing your FR vocabulary is important. Here, our FR experts have compiled the most important of those terms in a handy alphabetized glossary so you can create a culture of compliance.
An arc flash is a type of electrical explosion where temperatures can reach or exceed 35,000 °F. The Arc Flash hazard affects all who work in and around energized electrical equipment. This can include general industry electricians, maintenance workers and operators, as well as our electric utilities, including transmission, distribution, generation and metering.
Arc-Rated (AR) Protective Clothing
Arc-rated protective clothing protects from arc flash and electric arc hazards. AR garments are measured in cal/cm². The total AR clothing system must meet or exceed required arc protection levels. Remember, all AR is FR, but not all FR is AR.
Breakopen is the formation of holes in the fabric during arc rating testing. This is the point of failure of FR protective garments.
Energy Break-Open Threshold is an alternative measure to ATPV when that measure cannot be used due to breakopen.
A rapid moving flame front that can be caused by a diffuse fuel, such as dust, gas, or the vapors of an ignitable liquid, without the production of damaging pressure. Flash fire is the primary hazard in the Oil & Gas industry, which includes exploration, drilling, field services and refining.
Hazard Risk Assessment
The first step in the creation of any PPE program is the Hazard Assessment. Federal regulations require employers to assess the workplace to determine if hazards that require the use of personal protective equipment are present or are likely to be present. These include impacts, combustible dust, fire/heat, and chemical hazards, among others.
HRC (Hazard Risk Category)
Hazard risk categories are defined by NFPA® 70E and assigned based on risk associated with electrical safety and arc flash. HRC levels determine the appropriate ATPV of flame-resistant clothing for a given task.
Replaces HRC in 2015 edition of NFPA 70E, the “0” category was eliminated in NFPA 70E 2015. The minimum ATPV’s for PPE Category 1 through 4 are the same as they were for HRC, and the new PPE table only specifies PPE for work within the arc flash boundary.
HRC 2 rated garments have an arc rating between 8 cal/cm² and 25 cal/cm² and are often referred to as “daily wear.”
HRC 3 rated garments have an arc rating between 25 cal/cm² and 40 cal/cm².
HRC 4 rated garments have an arc rating equal or greater than 40 cal/cm². These high ratings are achieved with a layered FR system. Download our FR Layering Fact Sheet to learn the do’s and don’ts of layering for FR.
Inherently Flame Resistant
Inherently flame resistant fabrics are engineered to be flame-resistant at the fiber level, and do not require any additional finishing.
The National Fire Protection Association is an agency whose task it is to promote and improve fire protection and prevention. They publish National Fire Codes.
Refers to NFPA’s “Standard on Flame Resistant Garments for Protection of Industrial Personnel Against Flash Fire.” NFPA® 2112 is the “go-to” industry consensus standard that addresses flash fire. It defines the testing methods and performance requirements for flame-resistant fabrics for this hazard.
The “Standard for Electrical Safety in the Workplace,” NFPA® 70E is meant to protect those working around potential arc flash hazards. Note that NFPA® 70E applies only to general industry electrical safety, not to electric utility workers.
Founded by the Occupational Safety & Health Act of 1970, The Occupational Safety and Health Administration’s (OSHA) mission is to “assure safe and healthful working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education and assistance.” Their general duty clause ensures a safe workplace for all employees and is the basis for all industry consensus standards. OSHA determines regulations and standards related to personal protective equipment.
The regulation states that power utilities make reasonable estimates of the incident heat energy to which their employee would be exposed, and that employees exposed to hazards from electric arcs wear AR clothing and other protective equipment with an arc rating greater than or equal to the estimated heat energy.
Founded in 1918, The American National Standards Institute coordinates and develops voluntary standards for products, services, and systems. The organization’s goals include performance consistency and product safety. It is the U.S. member body to ISO and IEC.
PPE (Personal Protective Equipment)
Personal protective equipment is specialized safety gear worn by an employee for protection against a hazard. Flame resistant/arc rated garments are a form of personal protective clothing worn against thermal hazards.
Moisture wicking fabrics pull moisture (sweat) away from the body and dry quickly, keeping the wearer cooler, dryer, and more comfortable. Bulwark iQ Series® FR Comfort Knits and Wovens are among the best moisture wicking FR garments available.
Breathability refers to how well a fabric allows air to be transmitted through the material. The more air that passes through, the cooler the wearer stays. Bulwark iQ Series® Endurance Collection is the first of its kind to offer high level FR protection in a material that is extremely breathable and durable.
Arc flash is a dangerous reality for those who work in the electrical industries. Since arc flash incidents cannot be predicted, it’s important that workers wear personal protective equipment (PPE) at all times. This whitepaper discusses how a layered system can protect workers while providing comfort and safety.
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Our free FR Home Wash magnet is packed with FR laundering quick tips. Request your free magnet to learn more, and keep it handy wherever you launder your garments.
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The best defense for you and your team is to stay educated on how you can reduce injury in the case of an arc flash. The Bulwark Protection PPE experts provide a wide range of tools and resources on how to select the right FR and tips on how to properly implement a safety program.
Cold stress may not be as well-known as heat stress, but when the temperature drops, it can pose a significant danger. Employers have many options for helping workers manage their exposure to cold while protecting them from flash fire and arc flash. This whitepaper discusses how you can layer FR/AR garments, how to implement a PPE program and the warnings signs of cold stress.
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Proud Members. Shared Mission.
With our commitment to relentless protection comes a commitment to doing our part to help ensure worker safety by pushing for standards and oversight. Nowhere is this obligation more essential than the world of NFPA® 70E, and in the lives of those Americans working near energized equipment. It is our pleasure to announce Bulwark Protection is now a proud member of the Partnership for Electrical Safety.
To learn more, please visit the Partnership for Electrical Safety website.
For industries operating in an inherently dangerous environment, the importance of selecting the right Personal Protective Equipment (PPE) can’t be understated. Our FR Handbook is a guide for safety managers, or whoever is tasked with ensuring the safety of their workers, through the process of selection, implementation, care, and maintenance and to outline the various FR (Flame-Resistant) and AR (Arc-Rated) clothing options that are available and compliant with the many regulations, responsibilities, and requirements.
As if industry safety regulations weren’t complex enough, for safety managers whose businesses operate in both the United States and Canada, PPE standards can vary. While standards are often similar, they are not identical. Understanding those most important differences can help inform purchasing decisions and help you protect employee safety. Download this whitepaper from our PPE experts for all the details you need to create a culture of compliance here in the U.S.A. and Canada.
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