Protection Against Humidity, Moisture, and Temperature

MIL-HDBK-1011/1

Table 4

Corrosion Resistance Comparison

STAINLESS

POLY-

APPLICATION

STEEL

COPPER

ETHYLENE

ALUMINUM

FRP

General

Very Good

Outdoor

Marine

Very Good

Good

Very Good

Outdoor

General

Very Good

Good

Very Good

Industrial

Fresh Water

Very Good

Good

Very Good

Sea Water

Very Good

Good

Fair

Very Good

15.4.2

Aluminum. Where the use of 6061 and 6063 series aluminum alloy

materials is permitted, anodize such materials after the cutting, bending,

forming, and drilling of the parts are completed. The item can then be

assembled. Do not use aluminum alloy where movement or contact of bearing

surfaces is expected.

Underground Facilities. Underground installations in the tropics

15.5

are characterized by high salt water tables, and high earth moisture content.

On small South Pacific islands, the entire underground system and embedded

materials are subject to constant salt water exposure and inundation. It is

not uncommon for ductlines, handholes and manholes to contain standing water

throughout the year. Select materials, cables, and splices on the basis of

resistance to chemical deterioration and submersion. Aluminum conduit is

especially subject to corrosion from salt and coral; therefore, do not use it

in underground situations. Note that underground cable is extremely

susceptible to subterranean termite damage. During installation of

underground cable, soil treatment with termiticide is recommended.

15.6

Protection Against Humidity, Moisture, and Temperature

15.6.1

Electrical Components. Do not treat switches, fuses, contacts,

oil-immersed transformer windings, and heater elements with fungus-resistant

coating. Other materials and components which are inherently fungus-resistant

or are protected by hermetic sealing need not be treated nor coated.

15.6.2

Circuit Elements (Low Temperature Rise). Coat circuit elements not

covered above and which have a temperature rise of not more than 75 degrees F

when operating at full load with a fungus-resistant varnish conforming to

62