Synergist - May 2010

virtually no incidents. But the guidelines in the new NFPA 70E suggested that those tasks were potentially far more hazardous than extensive industry-wide field experience had shown them to be.

Other employers raised concerns about the difficulty of applying broad consensus standards in certain settings. For example, employers that service equipment at a host employer may have multiple employees who perform diagnostic work on energized control panels. Some of these employees may make service calls at several locations in a single day, with little to no advance notice. Most panels would contain parts operating at less than 240 volts, which is one of the thresholds that determines whether workers should wear more protective PPE. Lines into the panels that were greater than 240 volts would be reduced to 240 or less in the area of the box on which work was to occur; still, the employee would likely be within the 48-inch NFPA 70E arc flash boundary for the higher voltage part. There could be multiple transformers serving circuits, as well, which the employees would not know beforehand. Under the new NFPA 70E, such conditions would probably require a detailed arc flash hazard analysis even if industry-wide experience suggested that injuries were highly unlikely.

Certain tables in the NFPA 70E standard are meant to help employers determine whether an arc flash hazard analysis is necessary. However, in some instances, using these tables requires knowledge of short-circuit current and fault clearing times—

information that is unlikely to be available to employees on service calls. Thus, work previously thought to present no extraordinary electrical hazards—where PPE could consist of appropriate gloves, boots, safety glasses, natural fiber pants and long-sleeved shirts—could now require calculation of an arc flash hazard analysis, an arc flash suit hood or balaclava and face shield, coveralls with an arc rating of at least eight, and the like.

No Surprises

Obviously, the intent of consensus safety standards like NFPA 70E is to prevent accidents before they occur. Even if an industry hasn’t experienced a certain kind of accident, that alone does not mean that a provision in a standard is unnecessary.

Unfortunately, a consensus safety standard meant to be broad in application will sometimes be over-inclusive. OSHA’s procedures for promulgating rules exist to minimize surprises on the regulated community and provide opportunities for rules to reflect the concerns of industry and workers. But if OSHA intends to use NFPA 70E to support citations issued for violations of the General Duty Clause, the agency and employers may end up debating what constitutes appropriate PPE in court. It would be better for all concerned to settle this argument during the rulemaking process.