OSHA's job is to ensure safety in the workplace, but in many cases, the agency leaves the methods for achieving safety to other standard-setting bodies. An excellent example of this arc flash safety. OSHA requires safe work practices, but it is the National Fire Protection Association's standard NFPA 70E: Standard for Electrical Safety in the Workplace that specifies safe work practices when arc flash is a hazard.

The 2009 edition of NFPA 70E was approved and released on Sept. 5. It contains a number of important changes that require many companies to change the way they operate. These changes affect labels on equipment, arc flash hazard analyses, required personal protective equipment (PPE), calculation of the protection boundary and training requirements. No longer will it be possible to get away with postponing a full arc flash hazard analysis until some unspecified future date, nor to leave panels unlabeled under the assumption that no one will ever work on them while they're energized.

NEW ARC FLASH LABEL REQUIREMENTS

New NFPA 70E Article 130.3(C) requires arc flash warning labels to include, at a minimum, the arc flash incident energy or required level of PPE.

Up to this point, putting a generic label on equipment warning workers of potential arc flash hazards would fulfill the requirements of the 2004 NFPA 70E and the National Electrical Code, both of which say that all equipment that might be worked on while energized must have an arc flash warning label. According to NFPA 70E, if you work on live equipment operating at 50 volts or more, then you must perform an arc flash hazard assessment. Even if you always deenergize equipment before working on it, an arc flash hazard assessment should be performed to determine the type of PPE to use when verifying that power is off.

Because of these misunderstandings, some employers erroneously have avoided engineering requirements by applying generic warning labels. They may have written something into their safety programs to the effect that, before working on something energized, check out NFPA 70E and perform an arc flash study (usually using the so-called Table Method). While they might have it written into their safety program, they probably don't do it.

This approach now is outdated. The 2009 edition of NFPA 70E requires employers to determine the incident energy or required level of PPE and display that information on the warning label posted on each piece of electrical equipment that may be worked on while energized, or when verifying power is off.

Under the new edition of the standard, it no longer is possible to get away with postponing an arc flash hazard analysis until some unspecified future date, or to leave panels unlabeled under the assumption that no one will work on them while they're energized.

NFPA 70E Article 130.3 now says that the analysis must be reviewed at least every 5 years or whenever a major modification occurs. This means that the label should include a date and the date must be documented. The analysis must be reviewed when major changes occur or, at a minimum, every 5 years.

MAKE THE LABEL COMPLETE

Putting only the minimum required information — either incident energy or required level of PPE — on the label is short sighted, because it may leave workers without essential information. If the label on a panel says simply 18 cal/cm2, for example, the worker would be required to know that this level of incident energy corresponds to Hazard Risk Category 3, which, in turn, requires the appropriate PPE for that hazard risk category.

While some questions could be answered by placing a poster in the dressing room, it makes more sense to put all the information — incident energy, hazard risk category, required level of PPE and the particular items of PPE required — right on the label. This information usually is gathered during an arc flash hazard assessment, and although it's not specifically required, some engineering service firms provide labels that include the complete information.

It's a good practice to also include shock and flash protection boundaries, available fault current and voltage level on the label. Figure 1 shows a label that provides the minimum required information and more.

PERFORMING AN ARC FLASH HAZARD ANALYSIS

Since equipment must now be labeled with the incident energy and required level of PPE, someone must conduct an arc flash analysis before work is done on energized equipment. This is an important change.

There only is one exception to this requirement: the 2009 Edition of NFPA 70E states that an arc flash analysis is not required if the circuit is rated 240 volts or less and is supplied by a single transformer rated less than 125 kVA.

It is important to point out that, although an arc flash assessment is not required under this exception, shock hazards remain that must be guarded. A shock hazard analysis must be performed if workers could be exposed to energized circuit parts. The shock hazard analysis determines the voltage of the live parts, shock protection boundaries (limited, restricted and prohibited) and proper shock protection PPE to be used.

CHANGES TO REQUIRED PPE

OSHA, in 29 CFR 1910.132(d), says that the employer must assess the workplace for hazards. If hazards exist that require PPE, the employer must select the right PPE for the worker, must communicate that selection process to the worker and must select the type of PPE that properly fits the worker. In OSHA subpart S, which covers electrical workers in general industry, 1910.335(a)(1)(i) requires the employer to provide the electrical PPE and also requires the employee to use it.

Separately, NFPA 70E Section 130.7(A) — Personal and Other Protective Equipment — requires that employees working in areas where electrical hazards are present be provided and use protective equipment that is designed and constructed for the specific part of the body to be protected and for the work to be performed. It is worth noting that the PPE requirements of 130.7(A) consider only the thermal effects of arc flash, and do not necessarily provide protection from other physical trauma that might be caused by blast waves, high-speed projectiles, etc.

The table Protective Clothing and Personal Protective Equipment (click here for full-size PDF) summarizes the new requirements for all hazard risk categories.

CHANGES TO HAZARD RISK CATEGORY 1 PPE

Most of the changes in PPE requirements apply to Hazard Risk Category 1. In an average manufacturing facility, an estimated 80 percent of electrical work will be done in Hazard Risk Category 1 or lower.

One significant change is that standard blue jeans no longer are acceptable for use when Category 1 risks are involved. In the 2004 version of NFPA 70E, a worker was allowed to use a long-sleeved fire-resistant (FR) shirt rated for 4 calories and standard blue jeans if they had a certain weight per square yard. No one ever paid any attention to the fabric weight of the material, and fabric weight certainly wasn't marked on the blue jeans at the store.

Under the 2009 edition of the standard, for Category 1, workers must wear long pants that have a rating of 4 calories or more, and that are verified by ANSI as FR pants and labeled accordingly.

When it came to headgear, under the 2004 edition of NFPA 70E, a worker could walk up to a panel and open it as long as he or she was wearing a hard hat and a pair of safety glasses. Under the 2009 edition, the worker also must wear a face shield rated for 4 cal/cm2 or higher, which attaches to the hard hat and covers the face down to the chin, or an arc-rated flash suit hood.

In the 2004 edition of NFPA 70E, hearing protection and leather gloves were required for Hazard Risk Categories 2* and higher. The 2009 edition of NFPA 70E now requires hearing protection and leather gloves for all hazard risk categories.

For certain tasks — going into a 277/480 V panel to open it up and just test for voltage, for example — Table 130.7(C)(9) assigns Hazard Risk Category 2*.

The 2004 edition of NFPA 70E states that for PPE in a 2* situation, in addition to all the other requirements for Category 2, the worker had to wear a double-layered flash suit hood and hearing protection. The 2009 edition allows the flash suit hood to be replaced by a balaclava (sock hood) in combination with a face shield rated for 8 calories or more.

CALCULATING FLASH PROTECTION BOUNDARIES

The mathematical method of calculating the Flash Protection Boundary has become more conservative. The 2004 edition of NFPA 70E said that the Flash Protection Boundary was 4 feet (the default value) as long as the product of the number of cycles it took the upstream protective device (fuse or circuit breaker) to open and the available fault current did not exceed 300 kA cycles. For example, if the available fault current were 100,000 amperes, the maximum clearing time of the upstream protective device could not exceed 3 cycles (300 kA cycles). Most companies tended to assume that the value for the panels in their facilities was less than 300 kA cycles, and that was often a good bet. But under the 2009 edition of NFPA 70E, the maximum allowable product is reduced to 100 kA cycles to assume that the flash protection boundary is 4 feet. So some existing studies and labels may not be accurate and other methods of calculating the Flash Protection Boundary distance must now be used.

One of the easiest ways to ensure that a given location will remain below 100 kA cycles is to install current-limiting fuses, which can clear faults in less that 1/2 cycle. That's low cost insurance to reduce hazards and ensure that a 4 foot boundary or less applies. If the Table Method is used to determine Hazard Risk Categories, the 2009 edition of NFPA 70E also allows the Hazard Risk Category to be reduced by one category if current-limiting fuses are used and operate in their current-limiting range.

CHANGES TO WORKER TRAINING

Several new articles in the 2009 edition of NFPA 70E address employee training. An addition to Article 110.6 (C) requires that employees be trained in CPR and recertified annually. Article 110.6(D)(1)(d) requires that employees be retrained before performing any tasks that are performed less often than once per year. And Article 100.6 (D)(3) requires that an employee must be retrained or receive additional training under any of the following circumstances:

  • If the supervisor observes, or annual inspections reveal, that the employee is not following the rules and regulations.
  • If new technology, new types of equipment or changes in procedures necessitate the use of safety-related work practices that are different from those the employee would normally use.
  • If the employee must use safety related work practices that are not normally used during his or her regular job duties.

Another new requirement, 110.6(E), requires that all training must be documented and employees must show proficiency, and that the documentation must be maintained for the duration of the employee's employment.

Companies with facilities in Canada should be aware that Canada is harmonizing its safety standards with the new edition of NFPA 70E, and the Canadian standard, CSA Z-462, will have the same or similar provisions.

CANADIAN STANDARDS

The most significant changes in the 2009 edition of NFPA 70E are 1) the requirement to put the actual incident energy and required level of PPE on the labels, 2) the changes in the required PPE and 3) the recalculation of the default protection boundary. Any employer that is or wants to be NFPA 70E compliant — and, thus, OSHA compliant — must do these things.


SUMMARY

Kenneth Cybart is senior technical engineer for Littelfuse Inc., Des Plaines, Ill. (http://www.littelfuse.com)