Avoid coming in contact with cleaning solvents.
Repaint electrical equipment only when necessary
Always wear gloves and goggles, but especially when
to prevent corrosion due to lack of paint. Paint only the
equipment is being sprayed. When spraying, hold the
affected areas. General repainting of electrical
nozzle close to the equipment. Do not spray cleaning
equipment or enclosures for electrical equipment only
solvents on electrical windings or insulation.
to improve their appearance is not desirable. Never
apply paint to any insulating surfaces in electrical
NOTE: Never use carbon tetrachloride as a
equipment. DO NOT PAINT OVER IDENTIFICA-
cleaning agent. It is a highly toxic (poisonous)
TION PLATES.
compound that is a suspected carcinogen. Its threshold
is 20 times lower than that of methyl chloroform,
Apply electrical insulating varnish to equipment
making it more dangerous. (Threshold is the point
only as necessary. Frequent applications of insulating
above which the concentration of vapor in the air
varnish build up a heavy coating that may interfere with
becomes dangerous.)
heat dissipation and develop surface cracks. Do not
apply insulating varnish to dirty or moist insulation; the
NOTE: Never use volatile substances, such as
varnish will seal in the dirt and moisture and make future
gasoline, benzene, alcohol, or ether as cleaning agents.
cleaning impossible.
Besides being fire hazards, they readily give off vapors
that injure the human respiratory system if inhaled
The two types of insulating varnishes commonly
directly for along time.
used in the Navy are clear baking varnish (grade CB)
and clear air-drying varnish (grade CA). Grade CB is
STEEL WOOL AND EMERY CLOTH/PAPER
the preferred grade. If it is not possible to bake the part
to be insulated, use grade CA.
Steel wool and emery cloth/paper is harmful to the
NOTE: Shellac and lacquer are forms of varnish,
normal operation of electric and electronic equipment.
but don't use them for insulating purposes.
The Naval Ships' Technical Manual and other technical
publications warn you against using steel wool and
emery cloth/paper on or near equipment. When these
CLEANING SOLVENTS
items are used, they shed metal particles. These particles
are scattered by ventilation currents and attracted by the
Cleaning electrical and electronic equipment with
magnetic devices in electrical equipment. This could
water-based and nonvolatile solvents is an approved
cause short circuits, grounds, and excessive equipment
practice. These solvents do not vaporize readily. Some
wear.
cleaning solvents are discussed in this section.
Clean the contacts with silver polish, sandpaper, or
When it is not possible to clean with a water-based
burnishing tools. After cleaning, use a vacuum to
solvent, u s e i n h i b i t e d m e t h y l c h l o r o f o r m
remove the excessive dust.
(1,1,1--trichloroethane). Methyl chloroform is a safe
effective cleaner when used in an adequately ventilated
NOTE: Never use emery cloth/paper and steel
wool for cleaning contacts.
area, and not inhaled Do not use it on warm or hot
equipment.
CATHODE-RAY TUBES
WARNING
Handle cathode-ray tubes (CRTs) with extreme
caution. The glass encloses a high vacuum. Because
of its large surface area, it is subject to considerable
Wear an organic vapor cartridge
force caused by atmospheric pressure. (The total force
respirator when using 1,1,1--trichloromethane
on the surface of a lo-inch CRT is 3,750 pounds, or
or make sure the work area has good local
nearly 2 tons; more than 1,000 pounds is exerted on its
exhaust ventilation.
face alone.)
When using cleaning solvents in a compartment,
The chemical phosphor coating of the CRT face is
always make sure the ventilation is working properly.
extremely toxic. When disposing of broken tubes, be
Rig an exhaust trunk for local exhaust ventilation if you
careful not to come into contact with this compound.
expect a high vapor concentration. Keep a ready-to-use
Certain hazardous materials are released if the glass
fire extinguisher close by. Never work alone in a
envelope of a CRT is broken. These hazardous
compartment.
materials are:
1-27
