Page 364 - Corrosion Engineering Principles and Practice

332 C h a p t e r 9 A t m o s p h e r i c C o r r o s i o n 333

FIGURE 9.4 Aircraft carrier’s top deck. (Courtesy of Mike Dahlager, Pacific
Corrosion Control Corporation)

operation where byproducts made of various waste materials can be
extremely corrosive to most metals.
Arid or tropical atmospheres are special variations of the rural
atmosphere. In arid climates there is little or no rainfall, but there
may be a high relative humidity and occasional condensation. This
situation is encountered along the desert coast of northern Africa. In
the Tropics, in addition to the high average temperature, the daily
cycle includes a high relative humidity, intense sunlight, and long
periods of condensation during the night. In sheltered areas, the
wetness from condensation may persist long after sunrise. Such
conditions may produce a highly corrosive environment.

9.2.4 Indoor
Normal indoor atmospheres are generally considered to be quite
mild when ambient humidity and other corrosive components are
under control. However, some combinations of conditions may
actually cause relatively severe corrosion problems. While there is no
typical contaminant or set of conditions associated with an indoor
atmosphere, any enclosed space which is not evacuated or filled with
a liquid can be considered an indoor atmosphere. If not ventilated,
such an environment may contain fumes, which in the presence of
condensation or high humidity could prove to be highly corrosive.
Even in the absence of any other corrosive agent, the constant
condensation on a cold metallic surface may cause an environment similar