Everyone wears clothes when out in public, but certain industries require their workers to wear specially designed and tested clothes to protect them from the hazards they could encounter in their workplace. Anyone working on or near electric power generation, transmission, and distribution equipment is required by law to wear specialized clothing for certain tasks.
EMPLOYER RESPONSIBILITY
OSHA 29 CFR 1910.269, Electric Power Generation, Transmission, and Distribution, requires employers to assess the workplace and determine whether an employee will be exposed to flame or electric arc hazards. If there is potential, the employer must either calculate or estimate (using specialized charts) the potential incident energy in heat the employee would be exposed to and provide the appropriate personal protective equipment (PPE) to the employee.
First, the employer must ensure that clothing worn by the employee is not untreated meltable fabric such as polyester, rayon, or fleece if the employee will be exposed to flames and arcs. The acceptable types of materials can be found in ASTM F1506, Flame Resistant and Arc Rated Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards.
Second, to paraphrase OSHA:
…the employer shall ensure that the outer layer of clothing worn by an employee, except for clothing not required to be arc rated, is flame resistant under any of the following conditions:
- The employee is exposed to contact with energized circuit parts operating at more than 600 volts,
- An electric arc could ignite flammable material in the work area that, in turn, could ignite the employee’s clothing,
- Molten metal or electric arcs from faulted conductors in the work area could ignite the employee’s clothing, or
- The incident heat energy exceeds 2.0 cal/cm2.
If an employee will be working in an area not regulated by OSHA 1910.269, the employer must provide arc-rated (AR) clothing for potential arc flash hazards under NFPA 70E, Standard for Electrical Safety in the Workplace. These areas include commercial, industrial, and residential construction workplaces. Sections 130.4 through 130.6 of NFPA 70E clearly state it is the employer’s responsibility to identify the hazards and provide the necessary AR clothing to mitigate those hazards. It also goes on to instruct the employer in proper inspection of that PPE.
Once it is determined that AR flame-resistant clothing is required, OSHA requires the employer to provide clothing that is appropriately rated for the potential hazard.
The employer shall ensure that each employee exposed to hazards from electric arcs wears protective clothing and other protective equipment with an arc rating greater than or equal to the heat energy estimated whenever that estimate exceeds 2.0 cal/cm2.
This protective equipment shall cover the employee’s entire body, except as follows:
- Arc-rated protection is not necessary for the employee’s hands when the employee is wearing rubber insulating gloves with protectors or, if the estimated incident energy is no more than 14 cal/cm2, heavy-duty leather work gloves with a weight of at least 407 gm/m2 (12 oz/yd2),
- Arc-rated protection is not necessary for the employee’s feet when the employee is wearing heavy-duty work shoes or boots,
- Arc-rated protection is not necessary for the employee’s head when the employee is wearing head protection meeting § 1910.135 if the estimated incident energy is less than 9 cal/cm2 for exposures involving single-phase arcs in open air or 5 cal/cm2 for other exposures,
- The protection for the employee’s head may consist of head protection meeting § 1910.135 and a face shield with a minimum arc rating of 8 cal/cm2 if the estimated incident-energy exposure is less than 13 cal/cm2 for exposures involving single-phase arcs in open air or 9 cal/cm2 for other exposures, and
- For exposures involving single-phase arcs in open air, the arc rating for the employee’s head and face protection may be 4 cal/cm2 less than the estimated incident energy.
As incident energy potential increases so must the protection level provided to the employee. It is the employer’s responsibility to assess the workplace, identify potential hazards, and provide adequate protection from the hazards.
USE AND CARE
ASTM F1449, Standard Guide for Industrial Laundering of Flame, Thermal, and Arc Resistant Clothing, and ASTM F2757, Standard Guide for Home Laundering Care and Maintenance of Flame, Thermal and Arc Resistant Clothing, provide guidelines for managing, inspecting, and caring for AR clothing whether home or commercially laundered. Another available method to train employees in the care of AR clothing at home may be found on manufacturers’ websites. Many provide videos, blogs, and instructional documents on how to properly maintain AR clothing.
Training the employee in the proper use and care of PPE is important to prevent damage to the protective value of the clothing. The employee’s ability to identify electrical hazards, their knowledge of electrical equipment and its nominal voltage, and understanding when proper PPE is required are important things for an employee to learn.
This knowledge will go a long way to ensuring that employees are protecting themselves from potential hazards. If it is worn, damaged, or deteriorated, it cannot adequately protect them from the potential hazard. Employees must learn to inspect all PPE before and after use.
BOOTS
Besides AR clothing, an employee must also protect their feet by wearing heavy-duty work boots or shoes if they will be exposed to the hazard of flames or electrical arc. Per OSHA 29 CFR 1910.136, Footwear Protection, Part (a): General Requirements.
Each affected employee shall wear protective footwear when working in areas where there is a danger of foot injuries due to falling or rolling objects, or objects piercing the sole, and where such employee’s feet are exposed to electrical hazards.
This indicates to the employer that the boot or shoe will likely also need to be safety-toed and meet ASTM F2413, Standard Specification for Performance Requirements for Protective (Safety) Toe Cap Footwear.
Additionally, the boots must be rated for electrical hazards (EH). EH footwear is manufactured with non-conductive, electrical shock-resistant soles and heels, and the outsole is intended to provide a secondary source of electric shock-resistance protection against the hazards from incidental contact with live electrical circuits and electrically energized conductors, parts, or apparatus. It must be capable of withstanding the application of 18,000 volts at 60 hertz for 1 minute with no current flow or leakage current in excess of 1 milliampere under dry conditions. Should the potential be assessed to exceed this, additional protection such as rubber dielectric over-boots or shoes will be required.
Cleaning and maintaining boots and shoes used for protection is also very important. Exposed toe caps indicate a breakthrough in the leather of the boot that will provide less arc and flame protection. Simple things such as broken, missing, or over-long laces can pose a tripping hazard, which can cause serious injury. Wear on the sole of the boot exposes the employee to step potential during a ground fault, and spilled flammable materials can soak into a leather boot creating a flame hazard.
CONCLUSION
Wearing the correct AR clothing and boots protects the employee from many potential hazards. Confirming that the equipment is clean and well-maintained is a key step in ensuring adequate protection. The employer must communicate to the employee how to inspect, clean, and maintain their PPE to ensure a safe and productive workplace.
REFERENCES
OSHA 29 CFR 1910.269, Electric Power Generation, Transmission, and Distribution.
ASTM F1506, Flame Resistant and Arc Rated Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards.
NFPA 70E, Standard for Electrical Safety in the Workplace.
ASTM F2413, Standard Specification for Performance Requirements for Protective (Safety) Toe Cap Footwear.
ASTM F1449, Standard Guide for Industrial Laundering of Flame, Thermal, and Arc Resistant Clothing.
ASTM F2757, Standard Guide for Home Laundering Care and Maintenance of Flame, Thermal and Arc Resistant Clothing.
OSHA 29 CFR 1910.136, Footwear Protection, Part (a): General Requirements.
Paul Chamberlain has been the Safety Manager for Asplundh Electrical Testing, LLC (formerly American Electrical Testing Co., LLC), a subsidiary of Asplundh Engineering Services, LLC since 2009. He has been in the safety field since 1998, working for various companies and industries. Chamberlain received a BS from the Massachusetts Maritime Academy.