MIL-HDBK-1003/11
Section 14:
CORROSION PROTECTION
14.1 Justification for Corrosion Protection. Corrosion can occur in almost
every metallic substance to some degree and in many cases to a severe
degree. A corrosion protection program directed against severe corrosive
conditions must be justified on the basis of economy, necessity, and
hazards.
14.1.1 Economy. The owning, operating, and maintenance costs of a
corrosion protection program should be less than the sum of the following:
a) costs of direct loss or damage due to corrosion of metal
structures,
b) costs of maintenance attributed to corrosion, including indirect
losses, such as leakage loss of tank contents,
c) cost increases for "overdesign" in excess of actual requirements
to allow for corrosion losses, and
d)
costs of shutdown, power failures, labor losses, and other
items.
14.1.2 Operational Necessity. Military facilities must be maintained in a
state of readiness at all times, with the importance of the mission
determining the degree of necessity for corrosion protection.
14.1.3 Hazards in Handling Materials. Preventive measures are necessary
where deterioration of structures serving fluid or gas piping, storage, or
using equipment, may result in dangerous losses by fire and explosion.
14.2 Causes of Corrosion. Corrosion is the disintegration of a metal by
one or more of the following causes:
14.2.1
Electro-Chemical (Galvanic).
14.2.1.1 Dissimilar Metals. Two contacting dissimilar metals or portions
of a metallic substance in contact with an electrolyte, such as water, soil,
or chemical solution, will cause an electric current to flow from the
relatively positive-charged metal (anode) to the relatively negative-charged
metal (cathode); as a result, metal ions go into solution.
14.2.1.2 Corrosion Protection. Refer to NAVFAC DM-4.06, Lightning and
Cathodic Protection, and NAVFAC DM-5.07, Civil Engineering, Water Supply
Systems, for additional details.
14.2.2 Differential Environments. Metals immersed in substances having
different concentrations of ions (such as different soil compositions) will
result in corrosion.
60
Previous Page
