of scrubbing, especially on Shot h panels.
Hot liquid and high
pressure hosing techniques did not seem to be as effective. That
high pressure hosing was less effective was further confirmed by
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employing this method initially on Shot 6panels.
Repetition of hosing, either low or high pressure, does not
seem to be profitable; however, repetition of scrubbing did yield
somewhat lower residual percentages in some cases, This is believed
to be simply the result of mechanical abrasion of the surface.
Subsequent tests were conducted at the Army Chemical Center.
Samples one inch square were cut from the Shot 4 alkyd resin painted
wood geometry panel and decontaminated by brushing with various
Solutions,
Results are presented in Table 5.1. “SVersene", and "Tide"
and "Cheer" (household detergents) removed ove: 90 per cent of the
five month old contamination which remained after operations at
Eniwetok, These tests were extended by scrubbing one foot square
areas of available panels with brushes and solutions. Results are
presented in Table 5.2 and show that although the reductions are not
as large as those obtained with the inch square samples, the use of
detergents is beneficial.
It was noted that intrinsically impermeable surfaces such as
asphalt and tar would derive little or no benefit from protective
coatings insofar as contaminability and decontaminability were
concerned, However, absorptive, permeable, and porous materials such
as wood, concrete, and ascestos cement were benefited to some extent,
by the use of coatings or sealing of joints. Of the several
coatings employed, the phenolic and alkyd formulations were the most
satisfactory and showed sufficient merit to justify further
experimentation in the laboratory. It is a matter of interest to
note that the phenolic coating was snlected initially because of its
satisfactory resistance to chemical agents and their highly corrosive
decontaminants.
It was observed that the decontamination operations. contributed.
waterially to the failure of some of the coatings, notably the
polyvinyl alcohol applied to the roll roofing panels and the lead
and o11 paint applied to wood panels, Also, the addition of "Versene"
to the scrubbing operation resulted in a visible run-off of asphaltic
material from roof surfaces tested which would contribute toward a
shorter service life of these materials. Further evidence of.
coating failure was indicated in several instances by chemical
analysis at Army Chemical Center.
For example, the top coating of
the Shot
alkyd resin wood panel was deteriorated to such extent that
only the primer coating ingredients could be identified. However,
it is recognized that the use of strong acids will be even more
destructive,
The usual sequence formerly prescribed for reclamation by
scrubbing called for a preliminary hosing to reduce the field,
followed by the application of the detergent, scrubbing, and a final
flushing. In view of the greater effectiveness of scrubbing as
compared to hosing, and in view of the limits normally placed on .
available water at many shore installations, it is believed that
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serious consideration should be given to eliminatiny the preliminary
hosing and substituting the sluicing on of a limited quantity of water
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