b. Test seam and bolts in the tank working from
b. Push plug through bolt hole, round head down.
the outer edge.
When bottom face of square head bears against the
c. Mix soap solution used for testing in accordance
section, plug is in expanding position.
c. Using two open-end wrenches, one to tighten
with instructions issued with tester.
hex nut to expand plug and the other to keep plug from
Motor starting switch must be in
turning, apply torque slowly to nut. At intervals. as nut
"OFF" position before connecting
is tightened, check plugs' resistance to turning. As
motor to an electric power source
resistance builds, increase turning force on the nut.
d. When plug no longer turns in bolt hole, apply full
outside the tank.
torque to nut until plug completely fills and seals the bolt
d. Measure inside length of the box. Use blue or
hole through the full thickness of sections involved.
red engineering keel and lay out this dimension along
3-5. Testing Seam for Leakage
a. The tank bottom must be clean and dry during
e. Position tester on tank bottom. Check starting
testing period. The seam and bolts are tested with a
switch for "OFF" position, and connect extension cord
vacuum seam tester (fig. 3-6) which is incorporated in
(7) to an electric power source outside the tank.
the storage tank erection outfit. Test the seam and bolts
f. Use a sash brush and wipe a heavy coating of
soap solution along edge of seam and bolt washers,
between marks on the seam.
g. Set valve (2) to discharge air from box (1) and
start motor-driven pump (4). Position box between
marks on the seam coated with soap solution. A
pressure gage is mounted inside the box. This gage will
indicate atmospheric pressure when pump is started.
When gage indicates an inside vacuum of 3 pounds per
square inch, large soap bubbles will appear at all points
of leakage. Make a mark with crayon on surface of the
area being tested along outside edge of tester at each
point of leakage. Tighten the bolts. Apply additional
soap solution and follow the procedure above until
Over-tightening of bolts will result in
damage to the strip gasket. Tighten
bolts just enough to stop leakage.
THREE-WAY CONTROL VALVE
Do not move off a tested area with
leaks until all points of leakage have
If tank is to be used for water
storage, do not apply sealing
compound to tank bottom.
Figure 3-6. Testing sears and bolts in tank bottom for leaks
Section II. ASSEMBLY AND INSTALLATION OF SIDE STAVES
3-7. Side Staves
a. Description. This is a single ring tank with six
Instructions contained in this section, covering
installation of tanks are keyed to the use of hook ladder
staves in the ring. All staves have special sections for
and scaffolds issued with the storage tank erection
pipe connections and a clean out opening. Top and
Large boxes or fabricated saw-horses and
bottom flanged edges of staves are called chimes, and
ladders are suitable substitutes for hook ladders and
side edges are called vertical seams. The staves have
scaffolds when erection outfit is not available.
a single row of bolt holes in each seam.
b. Assembling Side Staves.
Place all center
Stave assemblies for petroleum and
support ladder components and the manhole dome on
water storage tanks are all the same
bottom of tank prior to installation of last side
except for special fittings