NEAFC 32nd Annual Conference.pdf - New England Association of ...

NEW ENGLAlXlD .ASSOCIATION OF FII,,E CHIEFS
We have discussed the blast damage zone radii, and noted that these radii
scale up approximately with the cube root o£ the yield of the atomic or’hydrogen
bomb. I am sure you .are wondering whether the zones of interest, as
,regards incendiary action, should follow the same law.
The subject is complicated by the varying attenuation effects of the
Slight .haze normally present in the atmosphere. This. always; limits the range
of atmosphere visibility. When you can see only a few miles, the incendiary
effect of even the largest bombs cannot well extend much farther.
_As a practical working principle, you can, therefore, count on fighting
incendiary effects in the same blast damage zones for large bombs as for small
bombs. With houses demolished in the zone of A-damage, and streets obstructed
by rubble of the zone of B-damage, the zones of major interest to
fire fighters will normally be the zones of C and D damage,, where we would
expect moderate to minor blast damage. Be ready, therefore, with the super
bombs to plan to fight fires in the correspondingly enlarged zones of C and D
damage. However, if the visibility is rather low at the time of any bomb drop,
the area o£ incendiary action from the primary effects of the bomb rriay not
extend out much farther than the zone of B damage. I emphasize that even
though this situation should occur, we would have many secondary fires, in
the C and D zones, due to blast disruption.
You have heard, also, the most alarming things about the nuclear radiation
hazard involved in the explosion of the H-bomb. May I say in this connection
that it is probable that due to the size of the fire bail .(probably touching the
ground), the radiation hazard may be intensified. However, there is no new
type of hazard involved in this. type of explosion. The difference will be one
o]? intensity. Furthermore, the hazard of fall-out may be intensified. The
much publicized case of the Japanese fishermen is an example. The fall-out
was not widespread, but seemed to be localized, which is typical of fall-out.
I have ~here with me a copy of the much discussed film, "Operation Ivy,"
Some of you may have seen this, but, undoubtedly, many of you have not, and
I should like to s:how it to you. However, before I do that, I want to tell you
something about the research and the tests that we made in Nevada last spring
to learn more about the kind o~ materials that are primarily ignited by the
flash of the bomb, and the numbers and arrangement of such materials, which
would be exposed to the flash. We demonstrated that solid wood surfaces and
other common building materials are not-expected to be ignited directly by
atomic bomb thermal radiation; beyond the range of substantial blast damage.
Only those materials which we call kindling fuels, wi.ll be initially ignited. And,
for the purposes ~of our study of this problem, we divide kindling fuels into
three classes, as follows:
1. Transient exteridr fuels, materials such as dead grass., fallen leaves,
and discarded papers, which are found in outdoor locations and whose
occurrence varies over a period of time.
2. Fixed exterior fuels, materials functioning as an integral part of
fixed structures., such as rotted wood fences.
3. Interior fuels, building contents such as window coverings, up~
holstery, fabrics, magazines, and newspapers.
Prior to our tests in Nevada of last spring, we made a study of six major
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