Question: I have been reading up on Arc Rated Face Shields per the 1910.269 standard.

I know you need to wear an Arc Rated face shield if you are exposed to 9 cal/cm² or higher single phase-to-ground exposure on the utility side per the new OSHA standard.  I have also found where it states that a need for an Arc-rated shield [is necessary] if the cal/cm² rating is greater than 5 cal/cm² on three-phase exposure.  I understand that the three-phase calculation is different than the single-phase-to-ground [calculation].  Can you clarify for me how I should correlate this into our work practice?  Right now there are only a few circuits we might work on that are high calorie circuits, and we are informed of that prior to our arrival so we can have the proper PPE required.

Thanks.

Answer:

The OSHA 1910.269 standard is trying to make it practical that most single phase arc situations (overhead power lines) will not require a face shield.  Most other arc hazards (enclosures and any 3Ph arc) will require face shields.

The goal of OSHA, as I have understood it, was trying to be practical for overhead work and to take into consideration several things about overhead work.

1. Overhead work typically involved covering all phases as the worker moves in (reducing the risk of arc flash and preventing the risk of 3Ph arcs.)
2. Overhead arcs typically are “running arcs” which move from the spot they start at away from the source, so worker positioning can prevent much of the exposure.
3. Overhead arcs typically extend upward with the hot gasses and work practices typically place the worker below the work.
4. Overhead work is often completed with hotsticks and shotgun sticks, keeping the worker and the face further than some other work practices.

The hazard assessment is the responsibility of the company, so you CAN wear shields at a lower level but are not required to by OSHA.

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