I I I I I30 20IIt^t3" -t-LOWer CUTVeS: Visibi I ity ca 20 km l0 ,000Yield ktl0 Fig. A:2 Distances for flash burns The distance frou ground zero where lhe thernal radiation nay cause skin burns depends stroigly on both yield and atmoepheric conditions ' The chart shows, as a function of yield, the theor€tically calculated distance for second- and third-degree burns in a clear atnosphere and rn a virtually eopty Epace.Al35/392 ]innex fage -LtlJ -O"nrrg. """""4 tV ttr""r"l ta ]t2' under cl-ear or fairly crear atmospheric conditions, h,'^s, beings wilr receiveseeond-degree burn injuries to unprotected skin at a considerabr_e dlstance fromground zero. An indication of what these distances might re is given ty trr" tigr".,second.-alegree burns over 30 per cent of the bod.y witl resul-t in serious shock and. ingenera"] require nedical treatment within hours -for surviva.I. Untreated third-degreeburns wilL prove fatal if about 25 per cent of the ski.n area has been damaged.cl-othes will provide some protection depending on the thickness and materia] of t-hefabric, but vi]l eventually transporb heat thiough to the skin ""d (;i catch fire.