MIL-HDBK-1110
9.6.6.1
Relative Humidity and Dew Point. These conditions are
measured using a psychrometer. Most psychrometers consist of a
wet bulb thermometer, a dry bulb thermometer, and a standard
psychometric table. Using the table, the relative humidity is
obtained from the two temperature readings. More detailed
information is provided in Section 10.
9.6.6.2
Surface Temperature.
Surface temperature is measured
using a special thermometer in which the temperature sensing
element is designed to come into intimate contact with the
surface and to be shielded from the surrounding air. The surface
temperature of the coldest and warmest surfaces should be within
the limits of the specification. The location, temperature and
time of the measurement should be recorded in the record book.
9.6.7
Inspect Surface Preparation. Surface preparation
inspection procedures include inspecting equipment, and
associated materials (e.g., blasting medium and chemicals), as
well as the cleaned surface itself. Proper surface preparation,
as described in the specification, must be completed to obtain a
durable coating film. Additional information on surface
preparation is presented in Section 6. Many of the surface
preparation requirements involve visual inspection of the
surface, and some are subjective. For example, the specification
may require removal of loose paint (for example, paint that can
be removed by a dull putty knife), removal of surface chalk to
some specified level and feathering of edges on the remaining
paint film. To help avoid conflicts between the contractor and
the inspector, it may be useful to have the contractor prepare a
test surface about 4 by 4 feet that can then be used as a
standard for surface preparation. Photographs of the test
surface could be part of the inspection record. For steel, the
test surface should be protected by a clear coating.
When blast cleaning is part of the surface preparation,
it should be performed in a manner so that no damage is done to
partially or entirely completed portions of the work, adjacent
surfaces, or equipment. Usually blast cleaning should progress
from the top towards the bottom of a structure, should be carried
on downwind from any recently painted structures, and should not
scatter abrasive on or into surrounding buildings or equipment.
All dust from blasting operations must be removed by brushing,
blowing, or vacuuming before painting.
9.6.7.1
Abrasive-Blasting Surface Preparation Equipment and
Supplies
a) Air Cleanliness. Routinely (at least two times a
day or every 4 hours) inspect air supply lines for both blast
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