SAFETY
Get with the Program
Implementing the New NFPA 70E Electrical Safety Requirements
BY PAUL A. ZOUBEK
The National Fire Protection Association’s Standard for Electrical
Safety in the Workplace (NFPA 70E) is a global consensus standard that can be used to protect workers on occasions governed
by a less stringent standard (or by no standard at all). In the
United States, for example, OSHA adopted NFPA 70E for electrical installations ( 29 CFR 1910.303-308). Canada and Europe
have similar requirements.
NFPA 70E was last revised in 2004. The 2009 version of the
standard emphasizes electrical safety program management.
Hazardous Locations
NFPA’s National Electrical Code (NEC) defines hazardous locations as areas “where fire or explosion hazards may exist due to
flammable gases or vapors, flammable liquids, combustible dust,
or ignitable fibers.” A Class I hazardous location is an area where
flammable liquids are used or stored, and where—because of the
presence of flammable liquids—gases and vapors are within their
explosive limits and may constitute an explosion hazard.
Previously, Class I locations were separated into Division 1 locations, where ignitable vapor conditions were present continuously or intermittently, and Division 2 locations, where ignitable
vapor conditions were present only under unusual operating circumstances. The new version of NFPA 70E eliminates these divisions and replaces them with three zones (see Table 1). For more
information, consult the Flammable and Combustible Liquids
Code Handbook (NFPA 30) for guidance on implementing hazardous location electrical equipment.
New installations and modifications to Class I locations must
meet the zone classifications in 29 CFR 1910.307. The designer
Table 1. NFPA 70E Hazardous Location Zones
Zone
0
Examples
Tanks or open vessels
that contain flammable
liquids; spraying or coating
enclosures.
1
Description
Ignitable concentrations
of flammable gases and
vapors are present
continuously.
Ignitable concentrations of
flammable gases and vapors
are likely to be present under
normal operating conditions.
Areas where flammable
liquids are transferred from
one container to another.
2
Ignitable concentrations of
flammable gases and vapors
are not likely to be present
under normal operating
conditions.
Flammable liquids or flammable gases are used, but
would become hazardous
only in the event of an accident or unusual operating
condition.
must be familiar with the following in order to specify appropri-
ate electrical equipment, including light fixtures, light switches,
and conduit:
• The chemical substance(s) that will be used or stored in the
location.
• Each chemical’s autoignition temperature—the lowest temperature at which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame
or spark. The autoignition temperature is necessary for manufacturers of electrical equipment to specify a temperature classification (or “T” classification). The lower the autoignition
temperature, the higher the T classification.
• Typical ambient air temperature of the environment where
chemicals will be used or stored.
• How the chemical will be used (in order to specify Zone 0, 1, or 2).
Safety-Related Work Practices
Safety-related work practices apply to work performed on an energized system. A qualified person must have demonstrated competency and documented safety training. The 2009 version of
NFPA 70E places greater emphasis on this competency and electrical safety program implementation. The following is a chronological sequence of safety-related work practices as it applies to
workplace programs and employee training.
1. Risk Assessment
According to NFPA 70E Article 110.7(F), an electrical safety program requires a hazard/risk evaluation procedure before work
begins on an energized system. The procedure assesses potential
hazards and provides the risk assessment evaluator with subjective data on the probability of contact with the energized part,
frequency of a task, possibility of avoidance, and consequences
of injury. The assessment may be in the form of a job hazard
analysis or a quantitative risk assessment. I recommend that
readers utilize the risk assessment procedure in ANSI Z244.1.
Figure 1 shows a risk assessment procedure performed on a
panel board. The four-step sequence identifies the task, hazards,
consequences, and hazard mitigators.
2. Personal Protective Equipment Evaluation
OSHA Subparts I and S, and NFPA 70E Article 130.7, require
evaluation for PPE for worker protection. To protect workers from
shock and arc flashes, PPE requirements apply when a qualified
person will come within the limited approach boundary (described
below) of an energized part. The following highlights changes and
additions to PPE requirements in the 2009 NFPA 70E.
