TM-9-2330-356-14
SEMITRAILER, TANK: 5000 GALLON, BULK HAUL, SELF LOAD/UNLOAD M967 AND M967A1; SEMITRAILER, TANK: 5000 GALLON, FUEL DISPENSING, AUTOMOTIVE M969 AND M969A1; SEMITRAILER, TANK: 5000 GALLON, FUEL DISPENSING, UNDER/OVERWING AIRCRAFT M970 AND M970A1
TECHNICAL MANUAL; OPERATOR’S, UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL
OCTOBER 1990
TM-9-2330-356-14 - Page 303 of 528
TM 9-2330-356-14
be performed by authorized unit or direct support
personnel with an MOS of 77F or equivalent.
b.
There are several methods available to eliminate
combustibles from fuel tankers. The primary method is by
use of a purging chemical. Using a chemical to purge saves
time, labor, and material compared to other methods. It
greatly reduces the possibility of a combustible vapor
buildup after the purging procedure has been completed
and after the vapor test readings show a safe level.
c.
Alternate methods include steam, forced air, and
oil purge.
d.
The methods described here will be chemical,
steam. and forced air.
e.
If the semitrailer is being shipped after draining
and purging, refer to Chapter 4, Section XXI for
supplemental instructions.
4-100. Draining Tank
WARNING
Discontinue all operations if an electrical
storm Is threatening or In progress. Open
flames or other sources of ignition, such as
welding and cutting torches and ordinary
electrical equipment, shall not be introduced
in areas where flammable vapors may be
present. The tank being drained and purged
shall be statically grounded prior to, and
during, all operations.
a.
Before any purging is started, semitrailer tank
and piping must be drained into suitable containers, or an
oil/water separator.
b.
Select a level area 100-feet from any building,
source of ignition, or sewer system. Position semitrailer so
that the tank sump is in the lowest position.
c.
Have sufficient fire extinguishers available,
placed 50-feet upwind,
and manned by qualified
personnel.
d.
Static ground the semitrailer to an approved
(earth) ground.
e.
Place conductive metal or galvanized containers
under all drain points. Ground containers to tank and to
tank’s common ground. Grounding connections shall be
made to clean, unpainted surfaces.
CAUTION
Meters should be air dried thoroughly to
eliminate rusting of internal moving parts.
f.
Completely drain tank intetior, all piping, pump,
meters, and filter/separator. Remove all accessory items,
such as gages and floats, which might entrap fuel. Drain
the equipment that has been removed. Wipe dry all
connections. Cloths or mops used are to be washed, dried,
and stored, or disposed of safely.
4-101. Purging Tank
WARNING
Should an emergency arise requiring entry
into a tank which is not vapor-free, or which
has an oxygen
content less than
19.5 percent, personnel who enter the tank
shall have an attached lifeline and wear
protective respiratory equipment In the
form of either a self-contained breathing
apparatus or a full facepiece mask with a
pressure supply of respirable air. Another
person, also provided with respiratory
equipment, shall be stationed at the
manhole opening and remain there to
watch personnel In the tank and summon
assistance if a rescue operation becomes
necessary. Personnel should not enter a
tank which is in the explosive range.
All vapor-freeing work by any method
should be carried on outdoors, remote
from vehicles and other known sources of
ignition,
and the tank unit must be
stationed where flammable vapors will not
blow or drift indoors. Failure to follow this
warning may result in serious injury or
death to personnel.
Combustible vapor testing must be
conducted as prescribed In this manual
and current field manuals and technical
bulletins. Vapor testing should not be
conducted during steam cleaning since
excess moisture or lack of oxygen may
cause false readings.
Do not wear wool, nylon, silk, rayon, or other
clothing having a tendeny to generate static electricity.
b.
Wear clean cotton clothing with no metal buttons,
zippers, or fasteners. Remove all contents from pockets.
c.
Wear rubber boots and rubber gloves.
4-167
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