What's New with Arc Flash Standards
One example: Employees will be required to be retrained at intervals not to exceed three years.
- By Mark Saner
- Aug 01, 2012
The National Fire Protection Association (NFPA) 70E Standard for Electrical Safety in the Workplace has been around since 1979. The sections related to electric arc flash were introduced back in 2000. NFPA 70E is an important standard for protecting industrial electrical workers from the very dangerous affects of electric shock and arc flash. There have been many revisions, additions, and improvements related to arc flash safety over the years, and the 2012 edition is no exception. It includes a number of changes both to better clarify the intent of various sections and to provide additional protection measures. However, even changes that are intended to help clarify can often cause initial confusion, simply because they are changes. This article will review some of the changes that have raised questions and may need explanation.
The first change of note, and potentially the most confusing, was the replacement of the terms "flame-resistant" and "FR" with the term "arc rated." The purpose of this change was to eliminate the use of flame-resistant garments that use a type of fabric labeled as flame-resistant/FR that has not been arc tested and therefore does not have an arc rating. These fabrics have been tested for flame resistance using standards that have nothing to do with arc flash protection, but because they use the term FR, they have occasionally found their way into the market.
An example of a 70E section where FR was changed to arc rated is in section 130.7(C)(6), which previously read, "Body Protection. Employees shall wear FR clothing wherever there is a possible exposure to an electric arc flash...." The revised section in the 2012 edition reads, "Employees shall wear arc-rated clothing wherever there is a possible exposure to an electric arc flash...." This change forces the fabric to have been arc tested and the garment to be labeled with an arc rating shown as either the Arc Thermal Performance Value (ATPV) or Energy of Breakopen Threshold (EBT). The confusion comes in when users do not see the term arc rated on the garment. In the end, an FR garment that has an established arc rating shown on its label meets the new requirement. The standard does not require the use of the term arc rated; it simply requires there be an arc rating for the product. This is a pretty straightforward change, but someone reading it for the first time could naturally look for the words arc rated on a label.
Another significant change was combining Hazard Risk Category (HRC) 2 and 2*. The deleted HRC 2* was a little-discussed category that had a subtle but major difference from HRC 2. That difference was the requirement to have full head protection by using either a flash suit hood or a combination of an arc-rated faceshield and arc-rated balaclava. By combining these two categories, all HRC 2 tasks will now require full head protection.
You can see in the tables below the difference between the 2009 edition and the 2012 edition.
Table 130.7(C)(16) (2009 Edition)
Hazard/Risk Category/Protective Clothing and PPE
Hazard/Risk Category 2
FR Clothing, Minimum Arc Rating of 8 (Note 1)/Arc-rated long-sleeve shirt (Note 5), Arc-rated pants (Note 5), Arc-rated coverall (Note 6), Arc-rated face shield or arc flash suit hood (Note 7), Arc-rated jacket, parka or rainwear (AN)
FR Protective Equipment/Hard hat, Safety glasses or safety goggles (SR), Hearing protection (ear canal inserts), Leather gloves (Note 2), Leather work shoes
Hazard/Risk Category 2*
FR Clothing, Minimum Arc Rating of 8 (Note 1)/Arc-rated long-sleeve shirt (Note 5), Arc-rated pants (Note 5), Arc-rated coverall (Note 6), Arc-rated arc flash suit hood (Note 7), Arc-rated jacket, parka or rainwear (AN)
FR Protective Equipment/Hard hat, Safety glasses or safety goggles (SR), Hearing protection (ear canal inserts), Leather gloves (Note 2), Leather work shoes
Table 130.7(C)(16) (2012 Edition)
Hazard/Risk Category/Protective Clothing and PPE
Hazard/Risk Category 2
Arc-Rated Clothing, Minimum Arc Rating of 8 (see note 3)/Arc-rated long-sleeve shirt and pants, or arc-rated coverall; Arc-rated flash suit hood or arc-rated face shield (see note 2) and arc-rated balaclava (Note 7); Arc-rated jacket, parka, rainwear or hard hat liner (AN)
Protective Equipment/Hard hat, Safety glasses or safety goggles (SR), Hearing protection (ear canal inserts), Heavy-duty leather gloves (see Note 1), Leather gloves (Note 2), Leather work shoes
A New Retraining Requirement
There also has been a change in the arc flash boundary distance requirements that will require more analysis to establish. Where previously the arc flash boundary for voltages between 50 and 600 volts was specified at 4 feet, now working at 50 volts or greater requires an analysis to determine at what distance the incident energy equals 1.2 cal/cm2. That calculated distance will establish the distance at which a worker could be exposed to that incident energy.
Other changes include requirements such as these:
1. Employees will be required to be retrained at intervals not to exceed three years.
2. Electrical safety program audits now have a minimum audit frequency of three years.
3. Equipment labeling has been expanded to include the option of labeling with the minimum arc rating of the clothing or the highest HRC category, as well as adding the need to include the nominal system voltage and the arc flash boundary information.
4. Clearly stating that "Garments that are not arc rated shall not be permitted to be used to increase the arc rating of a garment or clothing system."
5. The arc flash protective equipment section added a category for head protection.
6. The clothing material restriction from using flammable synthetic materials was expanded to specify fabrics, zipper tapes, and findings rather than just clothing materials. (In the garment manufacturing world, findings, which can also be referred to as trims, means components other than the fabric, such as buttons, snaps, draw strings, etc.)
The other major electric arc flash standard is ASTM F1506, Standard Performance Specification 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. This is the standard that NFPA 70E specifies for its arc-rated apparel requirements. This standard, like NFPA 70E, has been around a while and has gone through numerous changes in an attempt to improve and clarify its ability to quantify the performance of arc-rated textiles. The ASTM committee charged with maintaining this standard is comprised of end users (primarily from utilities), electrical experts, and manufacturers of PPE, including FR fabric and garment manufacturers. The last revision was in 2010; since then, at least one task group has been working on revisions to be submitted for approval.
One of the main subjects of change has to do with how arc-rated garments are labeled relative to the fabric from which they are made. The fabric information required in the current edition of the standard includes care instructions, fiber content, and arc rating (either ATPV or EBT).
A number of the users on the committee have expressed a desire to know more fabric information. They are looking for information about the fabric's country of origin and information about the fabric mill that produced it. This type of information will give users the ability to verify the garments received today, next week, or even next year are made from the same fabric they previously tested and approved. There has been testing that shows fabrics from different mills can have arc ratings that vary enough to be a concern, even though the fabric is made from the same fiber blend and weight. The feeling is that if the fabric is made by the same mill and is the same type, fiber blend, and weight, it is likely the arc rating will be reasonably close, day after day, and knowing the country of origin will help identify a specific mill when a company has multiple mills in several countries, letting the users decide whether an outsourced fabric from another country is acceptable to them.
In the end, the purpose for changing safety standards such as NFPA 70E and ASTM F1506 is an attempt to make them clear, understandable tools for end users to evaluate the many safety products available on the market today. Feedback from users and new technology in PPE, manufacturing, and testing all play a role in why standards change over time. But the end goal is always to improve worker safety.
This article originally appeared in the August 2012 issue of Occupational Health & Safety.