TM 5-684/NAVFAC MO-200/AFJMAN 32-1082
3-11. Aluminum structures.
3-10. Painted steel structures.
Structures of aluminum alloy normally need no sur-
Most steel for indoor substations, and some steel for
face protection. Painting of aluminum alloy mem-
outdoor substations, is not galvanized and paint is
bers is not recommended except where esthetics is
used for preservation.
of prime importance.
a. Cleaning. All loose paint, blisters, and scale
must be thoroughly removed. Feather back the
3-12. Wood structures.
original coating around the damaged area with
Permanent wood structures should be inspected
sandpaper. Where the condition of the finish is
and treated as described in chapter 4, section IV.
poor, the paint should be removed entirely. Wire
Temporary wood structures may or may not be
brushing, sandpapering, or scraping is desirable
treated, depending on the local climate and ex-
where only partial surface cleaning is necessary.
pected life of the structure.
Paint removers will soften and aid in removal. How-
3-13. Concrete for structure foundations.
ever, the paint remover must be neutralized before
attempting to paint. For removal of oil and dirt,
Concrete is used extensively as a foundation for
weak solvents such as mineral spirits, other petro-
metal structures and for equipment. Concrete
leum thinners, or turpentine substitutes should be
should be visually checked during the course of
other maintenance and repair. Cracks wider than
b. Painting. Painting should be done after
about 1/16 of an inch (0.16 millimeters) should be
cleaning. All bare metal should be covered with a
repaired with a sand-cement grout. Badly deterio-
primer. Where only chalking has occurred, one
rated concrete should be replaced.
finish coat is sufficient. A zinc-chromate, alkyd-
3-14. Structure connections and joints.
resin primer followed by an alkyd-base paint is
a suitable air-dry combination for exterior sur-
Regardless of material, all connections and joints
faces. The primer coat should be allowed to air-dry
should be checked periodically for tightness of fas-
thoroughly and should be followed by two finish
tening hardware. Loose, broken, or missing parts
coats with sufficient time allowed between coats for
should be tightened or replaced as required to main-
tain a rigid structure.
Section III - SUBSTATION YARDS
3-15. Provision of yards.
damaged posts or other materials as required.
Chain-link fencing should be kept taut. Spalling or
In some cases, there may be no outdoor yard in
broken components of masonry fencing should be
connection with a substation. However, these are
exceptional situations, and most substations will
c. Grounding. Grounding must be maintained as
have an adjoining yard.
a safety feature. Visual inspection should be made
3-16. Fences for yards.
as a part of the monthly inspections, especially at
the gate bonding straps. Tests should be made as
Fence maintenance consists of material preserva-
prescribed in chapter 10, section III. Defects should
tion, maintenance of structural integrity, and main-
be corrected immediately.
tenance of a good ground. The following procedures
3-17. Warning signs at yards.
a. Material preservation. In noncorrosive loca-
Warning signs conforming to OSHA standards and
tions, double-dipped (ASTM A 90, Class II) hot-
stating the voltage should be placed on each fence
dipped galvanizing on chain-link fences will nor-
gate, on each substation building door accessible
mally furnish adequate protection for many years.
from outside the yard, and at intervals along the
In corrosive locations, use of an aluminized fabric
fence. At least one sign must be visible from any
should be the preferred installation. When material
position along the fence. Location and legibility of
preservation is required for steel or aluminum
all signs should be checked as a part of the monthly
chain-link fences, it should be described in section
II. Wood fences are not usually considered to pro-
vide adequate security for substations, and replace-
3-18. Substation yards.
ment with chain-link fencing should be considered.
Substation yards at the time of construction should
Screening, if required, can be provided with privacy
have been graded and cleared of vegetation. The
slats of polyester-fiberglass or aluminum.
b. Structural integrity. Security requires that
entire yard area should be covered with some kind
of earth covering. Concrete slabs, paving, or gravel
structure integrity be maintained by replacing