When will OSHA regulations require FR clothing for qualified electrical workers?
Federal OSHA published OSHA 1910.269 in 1994, and OSHA 1910.269(l)(6)(iii) states: “The employer shall ensure that each employee who is exposed to the hazards of flames or electric arcs does not wear clothing that, when exposed to flames or electric arcs, could increase the extent of injury that would be sustained by the employee.”
OSHA 1910.269(l)(6)(iii) clearly states the employer shall ensure all qualified electrical workers who could be involved in an electrical arc flash event do not wear clothing that could ignite and increase the extent of injury. If the qualified electrical worker’s clothing ignites and increases the extent of injury, the employer can (and mostly likely will) be cited. This OSHA regulation has been in effect since 1994, meaning electric utilities should have been in compliance since 1994.
This paragraph does not technically require FR clothing; it simply states the worker’s clothing must not increase the injury to the worker during an arc flash event. What else besides FR clothing could an employer do? The employer could de-energize the line or equipment, or the employer could move the worker further away from the arc flash, ensuring the worker’s clothes will not ignite. In most cases, employers have chosen FR clothing as the best option.
Are OSHA regulations going to change?
Yes, the proposed revision of OSHA 1910.269 and OSHA 1926 Subpart V, expected out in 2010, will require rated FR clothing when:
(A) The employee is subject to contact with energized circuit parts operating at more than 600 volts,
(B) The employee’s clothing could be ignited by flammable material in the work area that could be ignited by an electric arc, or
(C) The employee’s clothing could be ignited by molten metal or electric arcs from faulted conductors in the work area.
When OSHA publishes these revisions, FR clothing will become Personal Protective Equipment (PPE). Currently OSHA does not consider FR clothing PPE.
When developing an FR clothing policy, does the electric utility industry follow NESC or NFPA 70E?
When qualified electrical workers are operating, maintaining and constructing electric utility facilities they fall under the National Safety Code (NESC). In turn, the NESC is used to determine FR clothing requirements for qualified electrical workers, not the National Fire Protection Association (NFPA) 70E. The scope of the 2007 NESC states: “The NESC covers utility facilities and functions up to the service point.”
The NESC covers from the utility’s generator through the transmission system, the distribution system and to the customer’s service point. NPFA 70E covers the electrical system beyond the service point. When developing an FR clothing program for qualified electrical workers involved in the operation, maintenance and construction of the utility’s electric supply system, the electric utility industry follows the NESC, not NFPA 70E.
What arc flash assessment program does an electric utility use to determine the proper FR clothing rating?
The 2007 NESC 410.A.3 provides a clear process to develop an FR clothing program for qualified electrical workers. First, it requires a hazard assessment be performed to determine when FR clothing is required.
• Is it needed when reading meters? NO.
• Is it needed to walk into a substation for inspection purposes only? NO.
• Is it needed when working with new construction, which is not energized? NO.
• Is it needed when pulling and installing meters in a hot socket? YES.
• Is it needed when working on or near the energized bus of a substation? YES.
• Is it needed when working on or near energized lines, cables and equipment? YES.
Once the hazard assessment has been completed and a list of job tasks posing an arc flash hazard have been identified, a determination of the FR clothing rating needed for each task can be developed. For live line work on voltages of 1 kV and above, NESC Tables 410-1 and 410-2 can be used to determine the required FR clothing calorie rating. How is Table 410-1 and 410-2 used? Simply determine the maximum fault current for each voltage level at the substation breaker, and the clearing time for that fault current, enter Table 410-1 or 410-2 and read the required minimum FR clothing calorie requirement.
Is it that simple? Yes, the proposed OSHA 1910.269 and OSHA 1926 Subpart V states: “This paragraph does not require the employer to estimate the heat energy exposure for every job task performed by each employee. The employer may make broad estimates that cover multiple system areas provided the employer uses reasonable assumptions about the energy exposure distribution throughout the system and provided the estimates represent the maximum exposure for those areas. For example, the employer could estimate the heat energy just outside a substation feeding a radial distribution system and use that estimate for all jobs performed on that radial system.”
For energized work at voltages less than 1 kV, NESC 410.A.3 requires applicable work rules specified in NESC Part 4 be followed and engineering controls be used to limit exposure. And, in lieu of an arc hazard analysis, a clothing system of at least 4 calories shall be required.
When Subcommittee 8 of the NESC developed this requirement there was little industry data available for the Subcommittee to require higher levels of FR clothing protection below 1 kV. In the summer of 2008 a Subcommittee 8 Task Force developed a low voltage table, which is out for public comment and will be published in some form in the 2012 NESC. Also, recent low voltage arc studies are showing much lower calories levels are needed when working on the low voltage side of padmount transformers compared with earlier calculations.
What about rain gear and heavy winter clothing?
To protect a qualified electrical worker, as required in OSHA 1910.269, the worker’s clothing cannot ignite and increase the injury. If the worker is wearing an FR shirt under a 50/50 sweatshirt with an outer layer of non-arc-rated rain gear during an arc flash event, what is going to happen? The rain gear will most likely ignite and melt, and the 50/50 sweatshirt may also ignite, burning the non-protected portion of the worker’s body.
In this case, the FR shirt will do little to protect the worker if the outer layer of clothing ignites. The outmost layer must be arc rated to the potential arc flash the worker could experience. Yes, the rain gear must be arc rated. And yes, the outermost clothing layer, which might include a heavy winter jacket, must be arc rated to the potential arc hazard.
Does that mean all the worker’s clothing must be fully FR rated? No, if the qualified electrical worker has a maximum arc exposure of 8 calories and they are wearing rain gear rated at 16 calories and/or a heavy jacket or outerwear rated well above 8 calories, the heat from the arc flash will likely not penetrate the innermost layer(s).
Is an arc rated face shield required when working around energized equipment?
No, NESC 410.A.3 and OSHA 1910.269 do not require an arc rated face shield. Both the NESC and OSHA 1910.269 regulations relate to clothing, they do not cover PPE. Industry studies and arc flash accidents have shown that normal safety glasses do an effective job of protecting the eyes. However, a face shield should be strongly considered when working in confined spaces and around 480-volt equipment and conductors. In lieu of a face shield, consider an FR rated balaclava, which are often more comfortable and effective in cold weather.
This discussion covers only exposed energized lines and equipment found in the vast majority of the electric utility systems across the U.S. It does not include network systems and network protectors, metal clad switchgear and large load panels. This equipment will require further study in some cases, but the calculations are straightforward.