appropriate chemical tests fail to give a positive
response for a residual agent. Decontamination at naval
shipyards, advanced bases, or by shore-based personnel
will normally be of the 100% chemically complete type.
This level is not mission essential for shipboard units.
DECONTAMINATION OF THE SHIP
The purpose of decontamination is to remove or
reduce CBR contamination so that the ship can carry out
its mission without danger to the life or health of its
crew. Each type of contamination requires different
decontamination procedures. Radiological (nuclear)
contamination may be removed by washing it over the
side; CW agents may be neutralized; BW agents must
be destroyed.
Nuclear Radiation Decontamination
Complete decontamination of a ship usually
requires the service of a shipyard. However, radiation
levels can be reduced by shipboard personnel to the
point where radiation no longer presents a serious
hazard to the crew. Most of the radioactive particles can
be removed by washing down the ship. Two washdown
methods are used—mechanical and manual.
MECHANICAL METHOD.—The mechanical
method, called the ship’s water washdown system,
consists of a system of piping and nozzles that spray
water over all weather surfaces. Water is supplied by the
fire main.
NOTE
The washdown system actually is a preventive
measure against fallout, rather than a
decontamination method, because normally the
system is activated before the ship enters the
fallout area.
The water spray carries away the radioactive
particles as they fall on the ship. At the same time, the
flowing water fills in the cracks and crevices so that the
particles that do get through the spray cannot settle into
the cracks and crevices.
MANUAL METHOD.—If parts of the ship are
contaminated before the washdown system is turned on,
water from the sprinklers may not effectively reduce the
radioactivity because the slowly flowing water doesn’t
have enough force to wash away the particles. The areas
of heavy contamination must be hosed down with water
under pressure. Hosing and scrubbing down the ship is
the manual method.
Decontamination teams are formed to hose and
scrub down the ship. A team usually consists of six
people—the monitor, who is in charge; two hosemen;
and three other team members. The hosemen wash
down the hot spots with fire hoses, moving from the
areas of less contamination toward areas of greater
contamination, and working from top to bottom. Then
the areas are scrubbed by the remaining team members
with soap or detergent and water and are rinsed by
hosing (fig. 13-11). The hosing-scrubbing-hosing
continues until monitoring shows that contamination is
removed or at least reduced to a safe level. Keep the
contaminated water away from vent systems, doors, and
hatches, because washing away the particles does not
destroy them; they are simply being moved over the
side.
BW and CW Decontamination
BW decontamination means eliminating the
sources of infection. Using a chemical disinfectant is
the most effective way to decontaminate BW agents.
The type of disinfectant depends on the agent, the
material to be decontaminated, and sometimes the area.
Other methods include burning, dry heat, and moist
heat. Burning usually is unsatisfactory because it
naturally destroys surface material. An example of dry
heat is a hot air oven set at 180E . Moist heat includes hot
water or steam under pressure. Sunlight also is effective
in reducing BW contamination. The ultraviolet rays of
the sun kill most BW agents.
In CW decontamination, weather alone is the
simplest means. Bright sunlight is a decontaminant,
even in cold weather. However, lack of time,
unfavorable weather, or contamination of critical areas
may require a faster method. Enclosed spaces can be
steamed. All spaces can be treated with liquid
detergents. Water alone is often satisfactory as a
flushing agent; hot water or steam is better than cold
water.
13-24
Student Notes:
