I am away from my copy of 1584-2018 and wondering if one of you know the answer to this- is there a formula to extrapolate IE for distances closer than the 12� minimum working distance covered by the formulas and methodology in 1584-2018?

Thank you.

From IEEE 1584-2018 G.7.6 Working Distance:

The minimum working distance should be no less than
304.8 mm (12 in). Any smaller working distance could place the worker within the range of the arc plasma
cloud and metal droplets. No tests were performed at such short working distances. A minimum working
distance of 304.8 mm (12 in) was used because it is considered that the plasma cloud is not considered to have
exceeded a radius of 304.8 mm (12 in). The plasma cloud size and effect of direct contact with it should be
considered in future arc-flash model revisions.