It was determined that a respiratory hazard exists for
armored-vehicle crews not wearing protective masks during the first 24 hr
after a detonation. The degree of such hazard was not definitely established
due to @ lack of exact medical data on the effects of such exposure. However, adequate protection can be given personnel in an armored vehicle by
-using protective masks and/or a collective protector.
WI-519
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PRE~-SHOCK DUST STUDIES.
Operation TUMBLER-SNAPPER.
E. H. Bouton, C. S. Elder, J. S. Kemper, and E. F. Wilsey,
October 1952.
SECRET-RESTRICTED DATA
Previous atomic bomb tests had demonstrated that overpressures
resulting from the blasts were generally between one-third to one-half
of the predicted values.
This delay of the air shock was thought to
result from mechanical and/or thermal effects of the blast, such as the
raising of dust from the ground by thermal radiation.
Such dust might
absorb additional thermal energy and thus magnify the loss of overpressure.
The object of this project was to determine the concentration and the
particle-size distribution of the dust raised by thermal radiation.
Molecular-filter samples were used to determine absolute particle
concentrations in air, at selected positions with respect to ground zero,
at ground level and at 10-ft elevations.
Cascade impactors were also
installed at each location to collect airborne particles in five sizegradations, from 0.1 p to 100 up.
The very short air-sampling period
between bomb cetonation and arrival of the shock wave at the test position
made it necessary to synchronize all test mechanisms so that the passage
of air through the filters and impactors would start 2s seconds before
detonation tire.
A blast-closure device stopped the sampling just prior
to the arrival of the shock wave.
The presence of pre-shock dust in concentrations of from ten
to several hucired times background was established.
There was no
Significant cifference in the particle-size distribution of pre-shock
dust and background dust.
Little variation was shown in dust concentrations from skcot to shot.
To determine the depth of the pre-shock dust
layer, it is recommended that any future investigation of the phenomenon
include the taking of samples at several heights ranging from zero to
considerably tore than 10-ft% elevation.