SECTION 7—WELDING PROCEDURE AND WELDER QUALIFICATIONS
A.10 Flush-Type Bolted Door Sheets
A.4.2 The nominal thickness of shell plates (including shell extensions for floating roofs) shall not be less than that listed in 3.6.1.1. The nominal thickness of shell plates refers to the tank shell as constructed. The nominal thicknesses given in 3.6.1.1 are based on erection requirements.
Figure A-1—Flush-Type Bolted Door Sheet (See Table A-5)
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A SECTION AT HORIZONTAL CENTERLINE
Tank bottom cutout Door sheet
Bearing plate
38 mm (1.5") radius
End gusset Shell plate Tank bottom
LD
q q
Q spaces q spacing
K spaces k spacing
2400 mm (96") + 3d + 0q or 2q or 4q Q spaces q spacing Row 2
Row 1
q q 1.5d
Q spaces h spacing (1200 mm [48"] + 1.5d + f )
Shell plate
See Detail a Door sheet
End gusset 1.5d
radius Locking bars—see Detail b
Notch angle and flush-weld to bottom plate
Locking bar 1.5d
50 mm (2")
1.5d 1200 mm (48")
2400 mm (96")
f 1.5d
400 mm (16") radius
150 mm (6") radius 13 mm (1/2")
Drill all boltholes 3 mm (1/8") undersize and ream to exact bolt diameter after fit up
A End gusset
hD
SECTION AT CENTERLINE
50 mm (2") min
Intermediate gusset plates on 600 mm (24") (approximate) centers and between boltholes Bearing
plate
3600 mm (144") (arc distance)
Tack-weld to inside surface of shell Locking
bars
50 mm (2")
6 mm (1/4")
5 mm (3/16") 6 mm (1/4") 150 mm (6") min
Bearing plate
Detail b SECTION A–A
Detail a
300 mm (12") Web
19 mm (3/4")
19 mm (3/4")
tD
d
Door sheet
Tack weld Locking bar Milled-body machine bolts with heavy hexagon heads and heavy hexagon nuts
Apply fillet of synthetic rubber putty around bolthead before inserting bolt in hole
Brush bearing surfaces of door sheet and shell free of dirt and scale and
apply one coat of synthetic rubber putty 1.5 mm (1/16")thick to bolting surface of door sheet tS
Tank shell
Tank bottom Shell plate
Q spaces j spacing
Row 2 Row 1
Note 1 Note 2 Gusset
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1.5d
3600 mm (144")
Notes:
1. This weld shall be the same size as the size specified for the fillet weld attaching the shell to the tank bottom.
2. This weld should be the same size as the size specified for the fillet weld attaching the shell to the tank bottom.
After welding, the weld shall be ground smooth to clear the door plate.
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Table A-5—Flush-Type Bolted Door Sheets (See Figure A-1)
(All dimensions in mm) (All dimensions in inches)
Column 1 Column 2 Column 3 Column 4 Column 5 Column 1 Column 2 Column 3 Column 4 Column 5
Shell Thickness
ts Q q h j
Shell Thickness
ts Q q h j
6 7 51 185.0 105.6 1/4 7 115/16 7.375 4.165
8 8 51 161.9 95.7 5/16 8 115/16 6.453 3.766
10 8 51 161.9 95.7 3/8 8 115/16 6.453 3.766
11 8 62 162.6 102.3 7/16 8 21/4 6.477 3.945
13 8 62 162.6 102.3 1/2 8 21/4 6.477 3.945
Column 6 Column 7 Column 8 Column 9 Column 10 Column 6 Column 7 Column 8 Column 9 Column 10
K k tD hD f K k tD hD f
36 71.2 11 1355 65 36 2.837 7/16 537/8 21/2
30 82.0 11 1355 65 30 3.275 7/16 537/8 21/2
30 88.8 11 1355 65 30 3.533 7/16 537/8 21/2
24 107.9 13 1364 65 24 4.297 1/2 547/16 21/2
22 123.4 14 1364 65 22 4.892 9/16 547/16 21/2
Column 11 Column 12 Column 13 Column 14 Column 15 Column 11 Column 12 Column 13 Column 14 Column 15
LD
Number of Bolts Bolt
Diameter
d LD
Number of Bolts Bolt
Diameter d
Row 1 Row 2 Total Row 1 Row 2 Total
3336 0 7 156 20 1311/2 — 7 156 3/4
3336 0 0 146 20 1311/2 — — 146 3/4
3540 3 6 164 20 1391/4 3 6 164 3/4
3648 0 2 138 22 1413/4 — 2 138 7/8
3772 3 6 148 22 1461/4 3 6 148 7/8
Column 16 Column 17 Column 18 Column 19 Column 20 Column 16 Column 17 Column 18 Column 19 Column 20 Bolt
Length
Length of Bolt Thread
Square
Locking Bar Angle Web
Bolt Length
Length of Bolt Thread
Square
Locking Bar Angle Web
50 35 16 152 × 102 × 9.5 6 × 290 2 11/8 5/8 6 × 4 × 3/8 1/4 × 115/8
50 35 16 152 × 102 × 9.5 6 × 290 2 11/16 5/8 6 × 4 × 3/8 1/4 × 115/8
50 35 16 152 × 102 × 9.5 6 × 290 2 1 5/8 6 × 4 × 3/8 1/4 × 115/8
55 35 20 152 × 102 × 12.7 10 × 285 21/4 11/8 3/4 6 × 4 × 1/2 3/8 × 113/8 65 40 20 152 × 102 × 12.7 10 × 285 21/2 11/4 3/4 6 × 4 × 1/2 3/8 × 113/8
Column 21 Column 22 Column 23 Column 21 Column 22 Column 23
Intermediate Gusset
End Gusset
Bearing Plate
Intermediate Gusset
End Gusset
Bearing Plate 6 × 125 × 290 6 × 200 × 290 6 × 225 1/4 × 5 × 115/8 1/4 × 8 × 115/8 1/4 × 9 6 × 125 × 290 6 × 200 × 290 6 × 225 1/4 × 5 × 115/8 1/4 × 8 × 115/8 1/4 × 9 6 × 125 × 290 6 × 200 × 290 6 × 225 1/4 × 5 × 115/8 1/4 × 8 × 115/8 1/4 × 9 10 × 125 × 285 10 × 200 × 285 10 × 225 3/8 × 5 × 113/8 3/8 × 8 × 113/8 3/8 × 9 10 × 125 × 285 10 × 200 × 285 10 × 225 3/8 × 5 × 113/8 3/8 × 8 × 113/8 3/8 × 9 Note: Washers shall be used on both sides of the plate for shell thicknesses of 16 mm (5/8 in.) or less.
COPYRIGHT 2003; American Petroleum Institute Document provided by IHS Licensee=IHS Dealers/IHSINTL003, User=ERCACCESS,
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In US Customary units:
For shear loading on a raised-type door sheet:
where
N = number of bolts required in each end section of door plate,
a = cross-sectional area of the bolts (in.2),
f = distance from the bottom of the shell cutout to the centerline of the bottom row of bolts (in.).
A.10.2.5 The distance between centers of bolt holes shall not be less than three times the bolt diameter, and the spacing of bolt holes at the sealing edge of the plate shall not exceed seven times the sum of the minimum door-sheet thickness plus the nominal bolt diameter plus the washer thickness (if washers are used).
A.10.2.6 The tensile stress in the net section of the door plate at the first row of bolt holes next to the shell-plate cutout
shall not exceed 145 MPa (21,000 lbf/in.2), and at the subse- quent rows, the tensile stress shall not exceed 145 MPa (21,000 lbf/in.2), after allowance is made for the total shear- ing value or bearing value (whichever is less) of the bolts in the preceding row or rows.
A.10.2.7 The following provisions apply to flush-type bolted door sheets:
a. The girder shall be designed to withstand the bending moment that would result if the ends of the girder were on hard ground and the center was unsupported.
b. The load on the girder shall be equal to the weight of a col- umn of water with the following dimensions: 1) 0.03 times the tank radius, in m (ft); 2) the width of the shell cutout, in m (ft), plus 0.6 m (2 ft); and 3) the tank height, in m (ft).
c. The design length of the girder shall be equal to the width of the shell cutout, in m (ft), plus 0.6 m (2 ft).
Note: When, because of wear, the difference in the diameters of the bolts and bolt holes is approximately 0.5 mm (0.020 in.), it is recom- mended that the holes be rereamed and fitted with oversize milled- body bolts; however, the holes shall not be reamed so much that the efficiency of the bolted connection becomes less than 0.85. This point is reached when the bolt-hole diameters become 6 mm (1/4 in.) larger than the bolt diameters specified in Tables A-5 and A-6.
Figure A-2—Supports for Flush-Type Bolted Door Sheet
Shell plate
Tank bottom
Sand cushion Door
sheet Angle
Gusset 300 mm (12")
METHOD A—TANK RESTING ON EARTH GRADE, WITH OR WITHOUT RETAINING WALL
METHOD B—TANK RESTING ON CONCRETE RINGWALL
Cutout in ringwall 300 mm (12")
Length of shell cutout + 1.5 m (5'0") Tank bottom
Door sheet Angle Gusset
Shell plate
Concrete ringwall Sand cushion 300 mm (12")
Note: Before the bottom plate is attached to the angle, (a) a sand cushion shall be placed flush with the top of the angle, and (b) the earth fill and sand cushion shall be thoroughly compacted.
( )N ( )a (16,000) = ts(hc+2.5d+ f)(21,000)(0.90)
( )N ( )a (16,000) = ts(hc+4d)(21,000)(0.90)
00
00
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A.10.3 When a flush-type bolted door sheet is installed on a tank that is resting on an earth grade with or without a con- crete retaining wall and without a concrete or masonry wall under the tank shell, provision shall be made to support the fitting and retain the grade as shown in Figure A-2, Method A.
A.10.4 When a flush-type bolted door sheet is installed on a tank resting on a ringwall, a cutout with the dimensions shown in Figure A-2, Method B, shall be provided.
A.10.5 Openings larger than NPS 2 nominal pipe size in flush-type bolted door sheets shall be reinforced in accor- dance with 3.7.2, and the reinforcement shall replace the cut- out area of the door plate.