-6The foliowing system of grading burns based on
laboratory and field experiments has been found to hold:
Grade i)
2.3 cal/som* in 0.3 second =~ only
erythema present 24 hours after exposure.
Grade 2)
4.5 cal/em* in 0.3 second = patchy or
central coagulation necrosis.
Grade 3)
7.5 cal/om* in 0.3 second = complete
coagulation of surface without charring.
Grade 4)
.
10 cal/em” 2,in 0.3 second — coagulation
Grade 5)
1S cal/om* in 0.3 second - deep coagu-
of surface with the formation of an immediate steam bleb
persisting as an air’Tiiied blister.
lation with carbonization of the surface.
The additional considerations which pertain to
very high yield weapons are the absorption of heat by the
atmosphere, whicn is related to visibility, and the
relation of the injury produced to the time of delivery
of thermal energy.
The total amount of heat is directly
proportional to the energy release of the bomb.
As the
time of delivery of the thermal energy is increased, the
number of calories per square centimeter required to
produce the lesions mentioned increases.
With very large
yield weapons the figures given for the 0.3 second of
delivery must be augmented by 50 to 100%.
The scaling laws
given and the considerations derived by experiment lead to
the following approximate values for thermal flux in
calories per square centimeter at various distances and
under specified conditions of visibility.
TABLE I
Distances in miles at which certain total thermal energies
are delivered reiated to yield and visibility
Energy release
20
100
1
10
KT
KT
MT
MT
Visibility 4 miles
3 caljvem2
LO calfom*
1.3
2.2
3.5
4.8
0.3
1.5
2.7
ne
(more)
Visiviljty 35~-40 miles
3° calfeme
2.2
he 3
10.0
7.0
10 caljemé
1.3
2.8
6.8
13.0
a ae ee