Arc Flash FAQs

1Are there specific government regulations about the arc flash hazard and FR clothing?

OSHA 1910.269 – states “the employer shall ensure that each employee who is exposed to the hazards of flames or electric arc does not wear clothing that, when exposed to flames or electric arc, could increase the extent of the injury that would be sustained by the employee.” This law holds the employer responsible for ensuring that each employee exposed to electric arc flash is protected with the proper apparel, which has been interpreted by most utilities to mean FR clothing, although it is not specifically required in OSHA 1910.269.

2How can I be sure I’m in compliance with OSHA 1910.269?

For electric utility workers under 1910.269, compliance means meeting OSHA’s safety requirements for electrical work. From a practical standpoint, as long as a worker’s clothing does not melt, ignite or continue to burn during or after an arc or flame exposure, the worker is in compliance. Although OSHA does not specifically state the requirements to meet its safety standards, repeated rulings indicate that workers wearing flame resistant clothing – like the FR clothing available through Tyndale employee allowance programs – are in compliance.

3Does compliance with OSHA 1910.269 mean that I’m sufficiently protected?

Compliance doesn’t necessarily translate to protection. Protection is essentially protecting yourself from a burn. While OSHA states that clothing cannot contribute to a burn, it does not require workers to wear sufficient clothing to completely protect them from the arc itself. Therefore, you can be in compliance with the law, but still be severely injured from an arc flash.

4OSHA 1910.269 says that fabrics such as nylon, polyester, or rayon are not allowed. Aren’t there some FR fabrics that contain nylon and polyester? Are they still compliant?

Although the use of such fabrics as polyester, nylon, or rayon alone or in blends is prohibited by OSHA where there is an arc flash hazard, the use of these fibers in tested FR fabrics is permitted. (Many tested FR fabrics do contain these fibers, in fact.) In Paragraph 3b of OSHA’s guidelines for following CFR 1910.269, the following exclusions apply: “Clothing made from acetate, nylon, polyester, or rayon, alone or in blends, unless the employer demonstrates that the fabric has been treated to withstand the conditions that may be encountered, that is, made flame resistant or flame-retardant-treated, or that the clothing is worn in a manner that eliminates the hazard involved.”

Thus, FR fabrics that contain polyester or nylon are only permissible if they have been tested as flame resistant according to industry standards.

For the complete text of this interpretation, follow this link:

5What is NFPA 70E?

NFPA 70E 2009 Edition is the Standard for Electrical Safety in the Workplace. It’s published by the National Fire Protection Association. According to the document itself, NFPA 70E was created because “it became apparent that a need existed for a new standard tailored to fit OSHA’s responsibilities that would be fully consistent with the NEC [National Electrical Code].” It establishes thresholds for worker protective apparel based on exposure to arc hazard risk and is designed to protect workers that install, maintain or repair electrical systems.

Here are a few recent changes to NFPA 70E (contained in the 2009 Edition):

  • Arc Flash Hazard Analysis: Article 130.3 requires the arc flash hazard analysis be updated whenever a major modification or renovation takes place. In addition, the analysis shall be reviewed periodically, not to exceed five years.
  • Equipment Labeling: Article 130.3 (C) states equipment shall be field marked with a label containing the available incident energy or required level of PPE.Selection of Personal Protective Equipment: Article 130.7 contains several revisions with respect to arc flash PPE requirements. Additional categories of equipment, such as arc-resistant switchgear, have been added to the revised table.
6What work activities and which industries are impacted by NFPA 70E?

NFPA 70E covers “the installation of electric conductors, electric equipment, signaling and communications conductors and equipment, and raceways” in public and private premises, yards, lots and parking lots and equipment that connect to the supply of electricity and installations used by electric utilities that are not an integral part of a generating plant, substation or control center.

Specifically exempt from NFPA 70E are ships and watercraft, installations in mines, railway power used exclusively for operating rolling stock, communications equipment under exclusive control of communications utilities and transmission and distribution work performed by electric utilities.

7Why should I be concerned with NFPA 70E?

As a national consensus safety standard, NFPA 70E is not a law and it has not been incorporated into the Code of Federal Regulations. Therefore, compliance with it is not deemed mandatory. Even so, OSHA has cited it in cases where lack of compliance has resulted in a workplace accident. This has impacted a broad variety of work environments – from Fortune 500 companies to Federal Labs – and has resulted in increased standard awareness, improved worker safety and the recognition that compliance with NFPA 70E is of critical importance to companies and their employees.

8How can I be cited by OSHA if compliance is not required by law?

Typically, OSHA might cite non-compliance with 29CFR 1910.335(a)(1)(i) which requires the use of protective equipment when working where a potential electrical hazard exists or 29CFR 1910.132(d)(1), which requires employer assessment of workplace hazards and the use of personal protective equipment. These regulations, written in general terms, are supported by NFPA 70E. NFPA 70E helps employers by providing the requisite “how-to” for compliance. In addition, OSHA has used the “general duty clause” in the past when citing companies.

9What is the “general duty clause”?

The general duty clause is defined in the Occupational and Safety Health Act of 1970 –Section 5 (a)(1) and states “…each employer shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.” This clause has been cited in the past – and court precedent and the review commission have borne out the validity of the general duty clause given certain elements are present:

  • The employer failed to keep the workplace free of a hazard to which employees of that employer were exposed.
  • The hazard was causing or was likely to cause death or serious physical harm.
  • The hazard was recognized (i.e. safety, trade organization, industry customs).
  • There was a feasible and useful method to correct the hazard.

So, although NFPA 70E is not a standard or a law, the intent is clear: companies are expected to maintain a safe place of employment for their workers, including appropriate protection from electric arc flash. At Tyndale, we have years of experience in managing turnkey flame resistant apparel programs for companies and their employees. We offer flexibility and exceptional service, with the desire to develop and implement a program that’s right for your company.

10OK, I’m convinced that compliance with NFPA 70E is important to my company. What’s required of employers?

NFPA 70E requires that employers conduct a flash hazard analysis and provide clothing to workers designed to protect against the level of risk associated with each task. Recognize that the guidelines available in NFPA 70E are just that – guidelines. They are a good starting point, but are not a substitute for a complete flash hazard analysis.

11What is the NESC?

Published exclusively by the IEEE, the National Electrical Safety Code (NESC®) sets the ground rules for practical safeguarding of persons during the installation, operation, or maintenance of electric supply and communication lines and associated equipment. The NESC covers supply and communication lines, equipment, and associated work practices employed by a public or private electric supply, communications, railway, or similar utility in the exercise of its function as a utility. The NESC is usually adopted on a local or state level soon after its publication, though it is not a nationally enforceable law. It is typically updated every 3 years and can be purchased at Most states adopt the most recent edition within a few of years of its publication. The edition of the NESC was published in January 2010.

12What is a flash hazard analysis?

NFPA 70E describes a flash hazard analysis as “a study investigating a worker’s potential exposure to arc-flash energy, conducted for the purpose of injury prevention and the determination of safe work practices and the appropriate levels of PPE.” The analysis should also take into account the Flash Protection Boundary and the flame resistant clothing that employees within the Flash Protective Boundary should wear.”

13What is the flash protection boundary?

The flash protection boundary marks the distance of an approach limit from which a person could receive a second degree burn if an electrical arc flash were to occur. It is determined based on a series of variables including voltage and time of arc exposure (in seconds). Workers wearing clothing in the appropriate hazard risk category (HRC) will be protected against injury if exposed to electric arc flash.

14What are the guidelines wtihin NFPA 70E on how to assess the arc flash hazard and determine adequate protection for the worker?

NFPA 70E cites three methods for assessing a flash hazard: 1) conduct a flash hazard analysis. For companies with hundreds or even thousands of employees and a broad variety of work activities taking place around "momentary electric arc and...thermal hazards" every day, this could be an unwieldy task. 2) Use Table 130.7(C)(9)(a) from NFPA 70E to determine the hazard risk category for a specific task. This table includes a comprehensive list of the most commonly encountered tasks and the associated risk category--and the required protection--for each. Or, 3) Use Annex H from NFPA 70E. It provides a simplified, two category approach to flame resistant apparel. While the table and annex provide useful guidelines, remember that the approach recommended is to perform a flash hazard analysis.

15What do you recommend to help ensure sufficient protection?

The primary concept behind protection is that you should wear enough clothing to ensure that the arc's energy is absorbed by your clothing. There are five factors that determine the intensity of the arc. A typical scenario encountered might be:

  • 8 kA – Amperage • 6" arc gap
  • 8 kV – Voltage • 30 cycles
  • 12" distance from arc

Resulting in a 36 cal Arc.

Because of the variability in conditions leading to an electric arc, it is difficult to estimate a likely incident energy level for any particular job. In addition, it’s important to follow your company’s established safety procedures and follow the recommended care instructions for your clothing.

Typically, OSHA might cite non-compliance with 29CFR 1910.335(a)(1)(i) which requires the use of protective equipment when working where a potential electrical hazard exists or 29CFR 1910.132(d)(1), which requires employer assessment of workplace hazards and the use of personal protective equipment. These regulations, written in general terms, are supported by NFPA 70E. NFPA 70E helps employers by providing the requisite “how-to” for compliance. In addition, OSHA has used the “general duty clause” in the past when citing companies.