In lieu of calculating the point at which incident energy will equal 1.2 cal/cm 2, the standard also provides a table-based solution for determining an arc-flash boundary based on the properties of the electrical equipment under consideration. The NFPA prescribes specific calculations for determining the arc-flash boundary under Annex D of this standard. It is an OSHA-recognized consensus standard therefore, the arc-flash boundary has legal weight as a boundary that must be observed in workplaces in order for employers to meet their general duty obligations for workplace safety. The arc-flash boundary concept is defined by the National Fire Protection Association’s 70E standard.