OSHA Arc Flash Standards

OSHA 1910.132(d) requires employers to assess the workplace for all hazards, including arc flash, and if they exist, they are required to select the proper Personal Protective Equipment that will protect employees.

OSHA has been referring to NFPA 70E requirements that describe how to assess the workplace for shock and arc flash hazards and how to select proper Personal Protective Equipment to protect workers exposed to the hazards.

If an arc flash occurs and injures or kills a worker, the cost of not performing the assessment, can far exceed the cost of the assessment.

It has been about 6 years since I was involved with training people on arc blast awareness and protection. At that time, safety glasses, cotton shirts, and insulated shoes were required for any work in electrical cabinets. All cabinets had to be kept securely closed at all times, unless an electrician was actively engaged in working in a cabinet. If a cabinet is not required to be energized (for testing, measuring voltages, etc.) then all circuits in an open cabinet must be deenergized and the breakers locked out. No metal jewelry can be worn, and some facilities require insulated gloves to be used if equipment must be energized while working on it (for diagnosis, for example.) Only qualified personnel can have access to electric cabinets, which means that a machine operator cannot reset circuit breakers, unless he is specially trained to do so safely, and does so with appropriate protective equipment. Generally, defeating interlocks on cabinets (for example to allow doors to open without turning of the CB) is frowned upon. All of these are pretty reasonable, and typical in many settings.

Are there new, additional protections being proposed by OSHA or your Safety Director?

The short answer is that the OSHA standard particularly parts §1910.335(a)(1)(v) and §1910.335(a)(2)(ii) state that electrical arc flash is definable as a hazard is, "where dangerous electric heating or arcing might occur," and that in such places the employer "must fully protect the employee from all residual hazardous energy" either through guarding by itself or with guarding supplemented with PPE (personal protective equipment).

The word "might" in the first quote is interpreted to mean that an accidental cutting of wire which produces an arc is justification to apply the standard. Arcing that could cause a burn might occur with any live circuit over 50 volts if a wire is accidentally shorted to ground.

To "fully protect" someone from "all residual hazardous energy" would mean that the person must be protected from potential electric shock, burns, and shrapnel from an arc resulting in an explosion. To do this gaurding would have to totally enclose the arc or be supplemented with PPE which includes head and face protection, fire resistant clothing with condutive paths to carry current away from the person's body, insulated gloves, tools insulated for use with live voltage, and insulated footwear when working on live circuits

The following section is an excerpt from an article from http://www.OSHA.gov/ :

Question 2: Is flame-resistant clothing required for employees working on electrical installations covered by Subpart S?

Reply: OSHA's present requirements in Subpart S, Safety-Related Work Practices, are based on NFPA 70E-1983, which did not at that time include specific provisions for flame-resistant (FR) clothing [protective equipment]. Although more recent versions of NFPA 70E have included such body protection provisions, OSHA has not conducted rulemaking proceedings to update Subpart S by adopting comparable provisions specifically related to the use of FR clothing to protect against arc-flash hazards. OSHA's existing Subpart S, therefore, does not include a specific requirement for the use of FR clothing.

However, arc-flash hazards are addressed in the OSHA electrical safety-related work practices standards. For example, with respect to arc-flash burn hazard prevention, the general provisions for the Selection and use of work practices contained in §1910.333(a)(1) generally require deenergization of live parts before an employee works on or near them — i.e., employees must first render electric equipment safe by completely deenergizing it by means of lockout and tagging procedures. This single safe work practice significantly reduces the likelihood of arc-flash burn injury by reducing employee exposure to electrical hazards — i.e., exposure is limited to when the equipment is shut down and when the qualified employee verifies, by use of a test instrument, a deenergized state.

When employees perform work on energized circuits, as permitted by §1910.333(a)(1), tools and handling equipment that might make contact with exposed energized parts must be insulated in accordance with §1910.335(a)(2)(i). This work practice also reduces the likelihood of employee injury caused by an arc blast.

Arc-flash hazards are also addressed in §1910.335(a)(1)(v), Safeguards for personnel protection, which requires that personal protective Equipment (PPE) for the eyes and face be worn whenever there is danger of injury to the eyes or face from electric arcs or flashes or from flying objects resulting from an electrical explosion. In addition, paragraph (a)(2)(ii) of §1910.335 requires, in pertinent part, the use of protective shields, barriers, or insulating equipment "to protect each employee from shocks, burns, or other electrically related injuries while that employee is working . . . where dangerous electric heating or arcing might occur" (emphasis added). The §1910.335(a)(2)(ii) safeguard selected — shield, barrier, or insulating material — must fully protect employees from electric shock, the blast, and arc-flash burn hazards associated with the incident energy exposure for the specific task to be performed. However, in situations where a fully protective safeguard could be used as an alternative, OSHA will, under its policy for de minimis violations, allow employers to use, instead, safeguards that are not fully protective, provided that the employer implement additional measures.² The supplemental measures, which could include the use of arc-rated FR clothing appropriate to the specific task, must fully protect the employee from all residual hazardous energy (e.g., the resultant thermal effects³ from the electric arc) that passes the initial safeguard.

Where there is no §1910.335(a)(2)(ii) safeguard that would fully protect against the hazards, an employer is still obligated under the Occupational Safety and Health Act of 1970 to take reasonable steps that will protect the employee to the degree possible.⁴ As noted in the previous paragraph, the protection provided by a safeguard that is not fully effective can be augmented through use of other safety measures such as FR clothing and other appropriate PPE.

OSHA recommends that employers consult consensus standards such as NFPA 70E-2004 to identify safety measures that can be used to comply with or supplement the requirements of OSHA's standards for preventing or protecting against arc-flash hazards. For example, Section 130.3 of the NFPA standard establishes its own mandatory provisions for flash-hazard-analysis⁵ , which sets forth the criteria to define a flash-protection boundary and the personal protective equipment for use by employees within the flash-protection boundary. The goal of this provision is to reduce the possibility of being injured by an arc-flash. The analysis is task specific and determines the worker's incident-energy exposure (in calories per square centimeter). Where it has been determined that work will be performed within the flash-protection boundary, NFPA 70E specifies that flame-resistant clothing and PPE use either be based on the pre-determined incident-energy exposure data or be in accordance with the Hazard/Risk Category Classifications and Protective Clothing and Personal Protective equipment (PPE) Matrix tables contained in Sections 130.7(C)(9) and (C)(10), respectively.

Other NFPA 70E, Article 130 provisions, such as the justification for work through the use of an energized electrical work authorization permit, and the completion of a job briefing with employees before they start each job, additionally decrease the likelihood that exposure to electrical hazards would occur.

For the rest of the article follow this link:

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=25557

We just went through the NFPE 70 E requirements at the mill I work in. I am sure we spent allot of money to do this but it is required so we did it. We have different levels of required PPE according to how many amps a system has that one is around. It is really complicated and I would suggest you get a person that has experience in this area before going forward. One thing I would like to ask are you talking about arc flash from throwing breakers and/or working on electrical equipment or arc flash from welding? These are two very different things when it comes to deciding the proper PPE and what OSHA might require.

My entry above applies to persons working on energized electrical panels, so it would not apply directly to arc welding. I don't know the specific requirements for arc welding, but the following site may be helpful: www.arcadvisor.com or you can purchase a copy of the NFPA 70E standard at http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70E

The OSHA standard's objective is to create an environment "free of electrical hazards." The website http://www.labsafety.com/refinfo/ezfacts/ezf263.htm does a good job of summing up when OSHA would suggest using PPE for protection from electrical hazards:

NFPA 70E covers the full range of electrical safety issues, including safety related work practices, maintenance, special equipment requirements, and installation. It focuses on protecting people and identifies requirements that are considered necessary to provide a workplace that is free of electrical hazards... OSHA bases its electrical safety mandates, found in Subpart S part 1910 and Subpart K part 1926, on the comprehensive information found in NFPA 70E. NFPA 70E is recognized as the tool that illustrates how an employer might comply with these OSHA standards. The relationship between the OSHA regulations and NFPA 70E can be described as OSHA is the "shall" and NFPA 70E the "how."

OSHA mandates that all services to electrical equipment be done in a de-energized state. Working live can only be under special circumstances. If it is necessary to work live (>50 volts to ground), the regulations outlined in NFPA 70E, Article 130 should be used as a tool to comply with OSHA mandates Subpart S part 1910.333(a).

*NOTE: The "special circumstances" are - continuity of work is required or de-energizing the work would create additional hazards.

Arc-welding certainly produces a lot of heat and light energy. However, because of its low voltage, it does not generally produce a sudden Arc-flash that produces intense heat and light in a very short period time that can ignite clothing and burn unprotected skin, or explode, as when high voltage cables or equipment fail, or someone accidentally bridges two live wires, or a live wire and ground.

Arc-flash incident energy depends on the available fault current and clearing time of the upstream overcurrent protector. If the fault current is high or the opening time is long, the arc-flash incident energy can cause severe burns or worse.

Low voltage does not necessarily imply low hazard. Most arc-flash accidents occur at 480V and less.

Can any of the electrical type people tell me if 70E has anything to do with the arc flash that is associated with welding. I was under the impression that it only applied to the arc flash that can occur when flipping breakers and other electrical devises. I don't remember anything being mentioned when we had the yearly 70E training as pertains to lock out and tag out for electrical devises in the paper mill I work in.

Go to this website: http://www.electricityforum.com/arc-flash/nfpa-70e-regulations.html

It states that Chapter 3 of NFPA 70E "...specifically includes such things as electric arc welding equipment..."