This document describes the continued extension of the CBRN Casualty estimation methodology to include 1st and 3rd degree flash burns. Flash burns result from the initial thermal pulse from the nuclear weapon detonation. The thermal pulse from a detonation lasts from a fraction of a second to several seconds in duration (increasing with yield), and is assumed to result in exposure to the exposed skin on the body (typically not more than 50% of the body surface area). This analysis identified the threshold fluence values (Qt) for 1st and 3rd degree burns to bare skin and various uniform types.