API 650 - Section -5 (Design) Flashcards
Joint Design of plate thickness more than 5 mm (3/16), the weld thickness shall not less than ,,,,,,
one-third the thickness of thinner plate ans shall be atleast 5mm
The required shell thickness shall be the greater of the ,,,,,,,,,,,,,,, including any corrosion
allowance
design shell thickness
When specified by the Purchaser, plate with a nominal thickness of 6 mm may be substituted for ,,,,,,,,,,,, plate
1/4-in.
For diameters less than 15 m (50 ft) but greater than 3.2 m (10.5 ft), the nominal thickness of the lowest shell course shall not be less than ,,,,,,,,,,
,6 mm (1/4 in.).
The design stress basis, Sd, shall be either ,,,,,,,,,,,the yield strength or ,,,,,,,,,,,the tensile strength, whichever is less
two-thirds
two-fifths
The hydrostatic test basis shall be either ,,,,,,,,, the yield strength or ,,,,,,, the tensile strength, whichever is less
three-fourths (3/4)
three-sevenths (3/7)
Annex A permits an alternative shell design with a fixed allowable stress of ,,,,,,,,,,,,, and a
joint efficiency factor of,,,,. This design may only be used for tanks with shell thicknesses less than or equal to
,,,,,,,,,
145 MPa (21,000 lbf/in.2) 0.85 or 0.70 13 mm (1/2 in.)
The 1-foot method calculates the thicknesses required at design points ,,,,,,,,,,, above the bottom of each
shell course.
0.3 m (1 ft)
Annex A permits, The 1-foot method only for design
that shall not be used for tanks larger than ……..
61 m
(200 ft) in diameter.
A rectangular insert plate or thickened insert plate shall have rounded corners (except for edges terminating at the tank bottom or at joints between shell courses) with a radius which is ,,,,,,,,,,,,
greater than or equal to the larger of 150 mm (6 in.) or 6t where t
The periphery of thickened insert plates shall have a ,,,,,,,,,,,tapered transition to the thickness of the adjoining shell material when the insert plate thickness exceeds the adjacent shell thickness by ,
1:4
more than 3 mm (1/8 in.).
Openings in tank shells larger than required to accommodate a ,,,,,,,,,,, flanged or threaded nozzle shall be reinforced.
NPS 2
The cross-sectional area of the reinforcement shall be measured ,,,,,,,, coincident with the diameter of the opening
vertically
All bottom plates shall have a corroded thickness of not less than ,,,,,,,,,
6 mm (0.236 in.) [49.8 kg/m2 (9.6 lbf/ft2
all rectangular and sketch plates (bottom plates on which the shell rests that have one end rectangular) shall have a nominal width of not less than ,,,,,,,,,
,,1800 mm (72 in.).
Bottom plates of sufficient size shall be ordered so that, when trimmed, at least a ,,,,,,,,,,,width will project outside the shell or
50 mm (2 in.)
Line 12, tank bottoms requiring sloping shall have a minimum slope of ,,,,,,,, upwards toward center of the tank.
1:120
The drip ring shall extend at least ,,,, beyond the outer periphery of the foundation ring wall and then
turn down ,,,,,,,,at its outer diameter.
75 mm (3 in.) (up to 90°)
lap-welded bottom plates may be used in lieu of butt-welded annular bottom plates. if product stress for the first shell course is ….. or the maximum hydro static test stress is
≤ 160 MPa (23,200 lbf/in.2)
≤ 171 MPa (24,900 lbf/in.2)
Annular bottom plates shall have a radial width that provides at least ,,,,,,,,,between the inside of the shell and any lap-welded joint in the remainder of the bottom
600 mm (24 in.)
Permanent attachments may be welded directly to the shell with fillet welds having a maximum leg dimension of ,,,,,,,
13 mm (1/2 in.)
The edge of any permanent attachment welds shall be at least ,,,,,,from the horizontal joints of the shell and at least ,,,, from the vertical joints, insert-plate joints, thickened insert plate joints, or reinforcing-plate fillet welds.
75 mm (3 in.) 150 mm (6 in.)
Permanent attachment welds may cross shell horizontal or vertical butt welds providing the welds are continuous within these limits and the angle of incidence between the two welds is greater than or equal to ,,,,,
45 degrees.
Temporary attachments to shell courses shall preferably be made prior to welding of the ,,,,,,,,,,,,
shell joints
Design External Pressure (Pe): Shall not be less than ,,,,,,
0.25 kPa (1 in. of water)
Design Internal Pressure (Pi): Shall not exceed ,,,,,,
18 kPa (2.5 lbf/in.2)
A tank roof formed to approximately the surface of a right cone that is supported principally either by rafters on girders and columns or by rafters on trusses with or without columns
supported cone roof
A tank roof formed to approximately the surface of a right cone that is supported only at its periphery
self-supporting cone roof
A tank roof formed to approximately a spherical surface that is supported only at its periphery.
self-supporting dome roof
