TO 35-1-3 - Robins Air Force Base

TO 35-1-3
CHAPTER 7
SOUTHWEST ASIA OPERATIONS AND ENVIRONMENTS
7.1 GENERAL.
The Southwest Asia (SWA) Area of Responsibility (AOR)
consists of various regions from Afghanistan to South Africa
(Figure 7-1). The environmental conditions range from seasonal
high winds and high humidity to arid areas and low
winds. In many locations, there are negatively charged ions
called anions in soils which when combined with aggressive
sand storms, can spread through SWA. The degree that sand
and dust can penetrate equipment is dependent on many variables
such as wind speed and direction, size of the dust/sand
particles, protective shelter availability, and condition of the
equipment, such as deteriorated seals/gaskets and bent doors.
7.1.1.1 Soils and Humidity. Soils exposed to high humidity
in many of the operating SWA AOR locations will cause corrosion
or accelerate existing corrosion growth if left in contact
with metal surfaces. Even in arid areas, humidity is usually
present. During daylight hours, SE stored outdoors will heat
up causing expansion of panels which allows hot, moist air to
migrate into enclosed areas (Figure 7-2) or under non-permeable
equipment covers. When the equipment cools, the moisture
condenses and combines with the fine dust/sand particles,
increasing the potential for corrosion. The soluble materials in
the dust/sand form a crust as they dry (Figure 7-3) making
removal difficult. Anion-laden sand/dust entrapped in SE
exposed to high humidity will gather in the available moisture,
extract the soluble salts, and a corrosion cell could be established.
These salts will appear as white streaks on SE after the
water has evaporated off the units (Figure 7-3).
Figure 7-2. Sand/Dust Intrusion
Figure 7-1. SWA AOR
7.1.1 Environmental Effects. Extensive operations in a desert
can result in very fine sand and dust intrusion into SE. SE
that is positioned in SWA for extended periods is more prone
to exhibit significant corrosion problems. Sandstorms, which
are usually seasonal, can cause sand/dust to penetrate equipment
and become entrapped in inaccessible areas. During the
periods of relative calm there are usually significant amounts
of airborne dust, seen as a general haze, in the atmosphere.
Figure 7-3. Residue from Salts Caused by
Condensation
Change 4 7-1