Controlling a hazard at its source offers the best way to protect employees. Depending on the hazard or workplace conditions, OSHA recommends the use of engineering or work practice controls to manage or eliminate hazards to the greatest extent possible. For example, building a barrier between the hazard and the employees would represent an engineering control; changing the way in which employees perform their work would provide a work practice control.
When engineering, work practice and administrative controls do not seem feasible or do not provide sufficient protection, employers must provide personal protective equipment (PPE) to their employees and ensure that the employees use this equipment. PPE consists of equipment worn to minimize exposure to a variety of hazards. Examples of PPE are gloves, foot and eye protection, protective hearing devices (earplugs, muffs), hard hats, respirators, and body suits.
Two standards deal with personal protective equipment: OSHA 29 CFR 1910, Subpart S and NFPA 70E-2004. NFPA 70E offers requirements consistent with the OSHA requirements as defined in 29 CFR 1926, Subpart K.
As the electrical industry changes, contractors must become aware of the new challenges they face. The definition of a qualified person no longer consists simply of someone who has a familiarity with the hazards involved. NFPA 70E, Electrical Safety in the Workplace, defines a qualified person as “One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training on the hazards involved.” [Emphasis added.]
The standard introduces such terms as Arc Flash Hazard, Arc Flash Hazard Analysis, Flash Protection Boundary and Hazard Risk Classifications, all of which relate to personal protective equipment requirements.
The standard now requires PPE and protective clothing (PC) for all work near electrical hazards. NFPA 70E-2004, Article 130.7 states, “Employees working in areas where electrical hazards are present shall be provided with, and shall 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.”
Based on this requirement, the contractor must identify what type of PPE the identified hazard requires. For instance, for work performed within a “flash protection boundary” [as determined by the analysis outlined in Article 130.3 (A)], “The employer shall document the incident energy exposure of the worker (in calories per square centimeter). The incident energy exposure level shall be based on the working distance of the employee's face and chest areas from a prospective arc source for the specific task to be performed.”
Protective clothing constructed and tested in accordance with the test procedures required in ASTM F 18 standard has a rating in calories per square centimeter. The purchaser uses this information to determine whether or not the clothing offered will match the degree of hazard where the clothing will be worn.
If the clothing rating equals or exceeds the degree of the arc flash hazard, the clothing will protect the electrician from a second-degree burn in most exposures. However, to ensure more complete protection, the body parts that come closer to the hazard should have additional protection.
After determing the flash-protection boundary, the flash hazard analysis will provide the necessary information for the electrician to select the appropriate flame-resistant (FR) clothing.
NFPA 70E defines flame-resistant as: “The property of a material whereby combustion is prevented, terminated or inhibited following the application of a flaming or nonflaming source of ignition, with or without subsequent removal of the ignition source.”
A fine-print note further describes flame resistance. It “can be an inherent property of a material, or it can be imparted by a specific treatment applied to the material.” The terms for both flame-resistant and flame-retardant have been used to describe clothing characteristics. NFPA 70E uses the term flame-resistant to remain consistent with other NFPA standards.
The standard also states that, “when flame resistant clothing is worn to protect an employee, it shall cover all ignitable clothing and shall allow for movement and visibility.”
The required protection areas of the body include:
°Head, face, neck and chin
°Hand and arm
°Foot and leg
Nonconductive head protection is required wherever there is a possibility of head injuries from electric shock, burns from live electrical parts or danger from flying parts from an electrical explosion. The same requirements apply when similar hazards exist for the face, neck and chin.
The standard requires eye protection whenever a danger exists from electric arcs, flashes or from flying parts from an electrical explosion. Required body protection includes the use of FR clothing whenever a potential exposure to electric arc flashes above the threshold incident level for a second-degree burn might occur. The standard defines this threshold level as 1.2 cal/cm2. As stated previously, this area would exist inside the Flash Protection Boundary.
When a danger of hand or arm injury from electric shock due to contact with electrical live parts might occur, the standard requires the electrician to wear rubber gloves. In addition, the FR clothing worn for body protection must also cover the arms.
Shoes with insulated soles cannot serve as primary electrical protection. For foot protection, the standard requires the use of dielectric overshoes. For leg protection, the FR clothing used to protect the body must also protect the electrician's legs from exposure to the hazard.
NFPA 70 E-2004 provides Table 130.7 (C) (9) (a) that an electrician may use to select PPE instead of employing a flash hazard analysis. As stated in 130.7 (9), “The assumed short circuit current capacities and fault clearing times for various tasks listed in the text and notes to Table 130.7 (C) (9) (a). For tasks not listed, or for power systems with greater than the assumed short-circuit current capacity or with longer than the assumed clearing times, a flash hazard analysis shall be required in accordance with 130.3.”
The table lists the Hazard/Risk Category for multiple tasks that electricians normally perform. The tasks listed assume that the equipment is energized and the work is performed within the flash protection boundary and lists tasks that include panelboards rated at 240V and below to metal clad switchgear at 1kV and above. The hazards range from 0 to 4 and require either no protection (Hazard/Risk Category of 0) or the use of V-rated gloves and V-rated tools (Hazard/Risk Category of 4).
The code defines V-rated gloves as, “gloves tested for the maximum line-to-line voltage upon which work will be performed, and V-rated tools as tools rated and tested for the maximum line-to-line voltage upon which work will be done.”
NFPA 70E-2004 also provides a protective clothing and PPE matrix in the form of Table 130.7 (C) (10). The table provides guidance for protective clothing and equipment and the degree of protection required by the PPE based on the Hazard/Risk Category number.
All of the clothing requirements outlined in the standard include training of the electricians who must wear the clothing. NFPA 70E will obviously make an impact on the safety of all electricians, and employers must ensure they have a complete working knowledge of the standard and require that all electricians follow the requirements outlined. EC
MOORE, a licensed fire protection engineer, frequent speaker and an expert in the life safety field, is a co-editor of the current National Fire Alarm Code Handbook. Moore is a principal with Hughes Associates Inc. at the Warwick, R.I., office.