Figure 8-50. Rafter hanger installed.

TM 5-5430-209-12

section, since no further assemblies are made on it.

Keep the last deck section separated from all other

sections until it is installed in the deck.

f. Assembling Center Deck Plate. The center deck

plate consists of two semicircular, flat, steel plates. The

two plates are joined together by bolted lap joints. The

plate covers the umbrella support. The outer

circumference bolting circle laps over the inner edge of

the deck sections.

(1) Lay plate (1, fig. 8-56), numbered side up,

on tank bottom. Place blocking under lap seam of the

plate.

NOTE

Make sure blocking does not block entrance to

the bolt holes.

(2) Place a bolt channel under the lap seam of

the plate. Insert 1/2-by-11/4 -inch bolts (2) through all

except the last bolt hole on the inner and outer

circumference of the plate and channel.

Figure 8-50. Rafter hanger installed.

(3) Remove the blocking and place a bolt

retaining board under the bolt channel.

(17) Turn the deck section over with trussed

(4) Install strip gasket (3) along the full length of

rafters resting on the tank bottom. Remove all finger

the lap seam. Allow a 1/2 -bolt hole overlap at each

tightened nuts installed on the bolts.

end.

(18) Install strip gasket (1, fig. 8-48) along the

(5) Install steel recessed washer, cup side down,

full length of the right and left seams. Allow a 1-bolt

and nut on each of the bolts (2, fig. 8-56) protruding

hole overlap at each end of the seam.

through the plate. Be sure the rounded head of the nut

is against the washer. Tighten the bolts.

d. Assembling Special Deck Sections.

(6) Raise center deck plate assembly (5, fig. 8-

(1) Install pressure vacuum valve (2, fig. 8-54)

54) to the deck before the deck sections are completely

on the plate of the first deck section to be installed.

installed.

(2) Insert /2 by 1/2 inch bolts through 2-bolt hole

8-18. Installation of Deck Sections

channels. Work through the 8-inch hole and insert the

bolts through the section. Place blocking under the bolt

a. Scaffold for Deck. Install a scaffold around the

heads to hold them in place during installation of the

tank about 3 feet below the top chime of the third ring

gasket.

staves. Refer to paragraph 3-8 and install the scaffold.

(3) Install a 16-hole gasket over the bolts.

b. Gin Pole.

(4) Install a pressure vacuum valve over the

(1) To install the deck section (3, fig. 8-53),

bolts.

position the pole (1, fig. 8-32) with the foot spike (1, fig.

(5) Install nuts on the bolts and tighten.

8-33) placed in a bolthole in the bottom chime of the

(6) Remove the blocking used in step (2) above.

third ring staves. Follow the procedures in paragraph 8-

(7) Install pressure vacuum valve (2) on a hatch

14e.

deck plate (4). Follow the procedures in steps (1)

(2) Erect the pole at every vertical seam in the

through (6) above.

third ring. Install a temporary bracket (3, fig. 8-32) at

(8) Install blind hatch flange (3) on three hatch

every seam not occupied by a scaffold bracket.

deck plates (4). Use the same bolts, channels, and

(3) Install the pole on the vertical seam at the

gasket as in steps (2) and (3) above. Follow the above

point selected for the installation of the first deck

procedures.

section. Replace the bolt in the bottom chime each time

(9) The level indicator plate (6) is installed with

the pole is moved.

level indicator fitting (7) as received.

c. Adjusting Center Support. Check and adjust the

center support before installing the deck sections. The

e. Assembling Remaining Intermediate Sections.

distance from the top of the center support base plate

There are 35 intermediate deck sections assembled with

(6, fig. 8-51) to the top of the rafter support clips should

trussed rafters and strip gaskets. The trussed rafters are

be 22 feet 1-7/16 inches. Raise or lower the support as

placed under the right lap seams only. The above

required.

procedures do not apply to the last deck

8-31