(K, = 220) for 30 tower shots with } 2 100. The horizontal part of
line A represents the mean K-factor (K, = 25) of 40 airbursts. There
is a substantial difference between detonations on steel towers and
those that are air burst.
We consider a burst on a building to be
comparable to a burst on a massive steel or concrete tower; similarly
a treetop burst is comparable to an airburst.
The most critical point
for establishing the dependence of K-factor on building height appears
to be the Trinity shot, analogous to one megaton on a 30-story building.
If wooden towers can be considered analogous to treetop-burst conditions,
several points in the two figures are analogous to treetop bursts.
only well-established ones are those for Smallboy and the two Little
Fellers.
The
For lower elevations we have Koon, whose suspension does not
fit these categories, and Coulomb B, burst on a wooden tower but with
a poorly documented fallout pattern.
For air and treetop bursts, the Subcommittee recommends using line
A in Figures 1 and 2, which amounts to a factor of about 0.45 for
a scaled burst height, X}, of 10. This is uncertain to the extent
represented by the spread in the Small Boy data.
As for bursts on buildings, the available data indicate that
line B should be used, which is to say a height-of-burst correction
of only 0.87 at a scaled height of burst of } = 10. This effect
cannot reduce the K-factor below about 220 no matter how tall the
building. As in Chapter 1, DCPA needs a K-factor (K) that does
not reflect reductions for instrument response or ground roughness.
On this basis, the minimum K-factor (K,) for bursts on buildings is
about 390,