Design of Atmospheric Storage Tanks by API Std 650
 
  Calculation of Thicknesses by One-Foot Method (5.6.3)
                                 
  Tables y Standards
  - API Std 650 Welded Tanks for Oil Storage, para. 5.6.3
  - Minimum Plate Thickness by API Std 650 (5.6.1.1)
  - Plate Thickness by ASME / ASTM
  - Tables 5-2a and 5-2b Allowable stress for design & Hydrostatic Test conditions
                                 
  ONE-FOOT METHOD
                  (Enter values in yellow cells for calculations)
  DATA INPUT
Capacity (Barrels)
m³
G (Fluid Specific Gravity)
    Fluid Density, r (g/cm³) (1) Note (1): (Consider r ≥ 1 g/cm³ for the Hmáx calculation)     
Ground Resistance, Ps (Kg/cm²)
    Outage (m) (2) Note (2): (Distance from the maximum level to the upper edge)    
Course
Plate  Specification
Plates width, E (m)
Hydrostatic Test Stress, St (MPa)
Product Design Stress, Sd (MPa)
Corrosion Allowance, CA (mm)
Hmáx = 1000*Ps/r
cm          = m
Htank ≤ Hmáx
m
h = Hmáx-outage
m
D = (V 4/πh)⁰∙⁵
m           = m³          = barrels
Dtank
m           = m³          = barrels
No. of Course = Htank/E
                                 
                                 
  OUTPUT tmin & SELECTION tuse          
  Course Design Condition td
(mm) 		Hidrostatic Test Condition tt
(mm) 		tmin
(mm) 		tuse (*)
(mm) 		         
  t1          
  t2          
  t3          
  t4          
  t5          
  t6          
  t7          
  t8          
  Notes:                    
  - Dimensions in mm                    
- (*) Verified Minimum Thickness by API Std 650 (5.6.1.1)
                                 
  CALCULATING THE THICKNESS OF THE 1ST SHELL COURSE (N=1)          
N
H = Hmax - (N-1)*E
m
    t1d = 4.9D(H-0.3)G + CA   mm              
    Sd                    
t1t = 4.9D(H-0.3)
mm
    St                      
THICKNESS OF THE FIRST COURSE
  t1min is the higher value between t1d & t1t                
t1use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 2ND SHELL COURSE (N=2)          
N
H = Hmax - (N-1)*E
m
t2d = 4.9D(H-0.3)G + CA
mm
    Sd                    
t2t = 4.9D(H-0.3)
mm
    St                      
THICKNESS OF THE SECOND COURSE
  t2min is the higher value between t2d & t2t                
t2use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 3RD SHELL COURSE (N=3)          
N
H = Hmax - (N-1)*E
m
    t3d = 4.9D(H-0.3)G + CA   mm              
    Sd                    
    t3t = 4.9D(H-0.3)     mm              
    St                      
THICKNESS OF THE THIRD COURSE
  t3min is the higher value between t3d & t3t                
t3use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 4TH SHELL COURSE (N=4)          
N
H = Hmax - (N-1)*E
m
t4d = 4.9D(H-0.3)G + CA
mm
    Sd                    
t4t = 4.9D(H-0.3)
mm
    St                      
THICKNESS OF THE FOURTH COURSE
  t4min is the higher value between t4d & t4t                
t4use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 5TH SHELL COURSE (N=5)          
N
H = Hmax - (N-1)*E
m
t5d = 4.9D(H-0.3)G + CA
mm
    Sd                    
t5t = 4.9D(H-0.3)
mm
    St                      
THICKNESS OF THE FIFTH COURSE
  t5min is the higher value between t5d & t5t                
t5use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 6TH SHELL COURSE (N=6)          
N
H = Hmax - (N-1)*E
m
t6d = 4.9D(H-0.3)G + CA
mm
    Sd                    
t6t = 4.9D(H-0.3)
mm
    St                      
THICKNESS OF THE SIXTH COURSE
  t6min is the higher value between t6d & t6t                
t6use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 7TH SHELL COURSE (N=7)          
N
H = Hmax - (N-1)*E
m
t7d = 4.9D(H-0.3)G + CA
mm
    Sd                    
t7t = 4.9D(H-0.3)
mm
    St                      
THICKNESS OF THE SEVENTH COURSE
  t7min is the higher value between t7d & t7t                
t7use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 8TH SHELL COURSE (N=8)          
N
H = Hmax - (N-1)*E
m
t8d = 4.9D(H-0.3)G + CA
mm
    Sd                    
t8t = 4.9D(H-0.3)
mm
    St                      
THICKNESS OF THE EIGHTH COURSE
  t8min is the higher value between t8d & t8t                
t8use
                                 
  Design of Atmospheric Storage Tanks by API Std 650
 
  Calculation of Thicknesses by One-Foot Method (5.6.3)
                                 
  Tables y Standards
  - API Std 650 Welded Tanks for Oil Storage, para. 5.6.3
  - Minimum Plate Thickness by API Std 650 (5.6.1.1)
  - Plate Thickness by ASME / ASTM
  - Tables 5-2a and 5-2b Allowable stress for design & Hydrostatic Test conditions
                                 
  ONE-FOOT METHOD
                  (Enter values in yellow cells for calculations)
  DATA INPUT
Capacity (Barrels)
ft³
G (Fluid Specific Gravity)
    Fluid Density, r (Lb/ft³) (1) Note (1): (Consider r ≥ 62,43 Lb/ft³ for the Hmáx calculation)     
Ground Resistance, Ps (Lb/in²)
    Outage (ft) (2) Note (2): (Distance from the maximum level to the upper edge)    
Course
Plate  Specification
Plates width, E (ft)
Hydrostatic Test Stress, St (psi)
Product Design Stress, Sd (psi)
Corrosion Allowance, CA (in.)
Hmáx = 1728*Ps/r
in.           = ft
Htank ≤ Hmáx
ft
h = Hmáx-outage
ft
D = (V 4/πh)⁰∙⁵
ft            = ft³           = barrels
Dtank
ft            = ft³           = barrels
No. of Course = Htank/E
                                 
                                 
  OUTPUT tmin & SELECTION tuse          
  Course Design Condition td
(in.) 		Hidrostatic Test Condition tt
(in.) 		tmin
(in.) 		tuse (*)
(in.) 		         
  t1          
  t2          
  t3          
  t4          
  t5          
  t6          
  t7          
  t8          
  Notes:                    
  - Dimensions in inches                    
- (*) Verified Minimum Thickness by API Std 650 (5.6.1.1)
                                 
  CALCULATING THE THICKNESS OF THE 1ST SHELL COURSE (N=1)          
N
H = Hmax - (N-1)*E
ft
    t1d = 2.6D(H-1)G + CA   in.              
    Sd                    
t1t = 2.6D(H-1)
in.
    St                      
THICKNESS OF THE FIRST COURSE
  t1min is the higher value between t1d & t1t                
t1use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 2ND SHELL COURSE (N=2)          
N
H = Hmax - (N-1)*E
ft
t2d = 2.6D(H-1)G + CA
in.
    Sd                    
t2t = 2.6D(H-1)
in.
    St                      
THICKNESS OF THE SECOND COURSE
  t2min is the higher value between t2d & t2t                
t2use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 3RD SHELL COURSE (N=3)          
N
H = Hmax - (N-1)*E
ft
    t3d = 2.6D(H-1)G + CA   in.              
    Sd                    
    t3t = 2.6D(H-1)     in.              
    St                      
THICKNESS OF THE THIRD COURSE
  t3min is the higher value between t3d & t3t                
t3use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 4TH SHELL COURSE (N=4)          
N
H = Hmax - (N-1)*E
ft
t4d = 2.6D(H-1)G + CA
in.
    Sd                    
t4t = 2.6D(H-1)
in.
    St                      
THICKNESS OF THE FOURTH COURSE
  t4min is the higher value between t4d & t4t                
t4use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 5TH SHELL COURSE (N=5)          
N
H = Hmax - (N-1)*E
ft
    t5d = 2.6D(H-1)G + CA   in.              
    Sd                    
    t5t = 2.6D(H-1)     in.              
    St                      
THICKNESS OF THE FIFTH COURSE
  t5min is the higher value between t5d & t5t                
  t5use                
                                 
                                 
  CALCULATING THE THICKNESS OF THE 6TH SHELL COURSE (N=6)          
N
H = Hmax - (N-1)*E
ft
t6d = 2.6D(H-1)G + CA
in.
    Sd                    
t6t = 2.6D(H-1)
in.
    St                      
THICKNESS OF THE SIXTH COURSE
  t6min is the higher value between t6d & t6t                
t6use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 7TH SHELL COURSE (N=7)          
N
H = Hmax - (N-1)*E
ft
t7d = 2.6D(H-1)G + CA
in.
    Sd                    
t7t = 2.6D(H-1)
in.
    St                      
THICKNESS OF THE SEVENTH COURSE
  t7min is the higher value between t7d & t7t                
t7use
                                 
                                 
  CALCULATING THE THICKNESS OF THE 8TH SHELL COURSE (N=8)          
N
H = Hmax - (N-1)*E
ft
t8d = 2.6D(H-1)G + CA
in.
    Sd                    
t8t = 2.6D(H-1)
in.
    St                      
THICKNESS OF THE EIGHTH COURSE
  t8min is the higher value between t8d & t8t                
t8use
                                 
  Minimum Plate Thickness Especified by API Std 650 (5.6.1.1)
  D  Thickness of Shell Course
  (m) (ft)  (mm)  (in)
  < 15 < 50 5 0,1875
  15 to < 36 50  to <120 6 0,25
  36 to 60 120 to 200 8 0,3125
  > 60 > 200 10 0,375
         
  Plate Thickness   
 
  Nominal Size Thickness   Nominal Size Thickness  
  (mm)   (inches)  
5
0,1875
6
0,25
8
0,3125
10
0,375
11
0,4375
12,5
0,5
14
0,5625
16
0,625
18
0,6875
19
0,75
21
0,8125
22
0,875
24
0,9375
25
1
27
1,0625
28
1,125
30
1,1875
32
1,25
33
1,3125
35
1,375
36
1,4375
38
1,5
40
1,5625
41
1,625
43
1,6875
  45   1,75  
                     
  Table 5.2a—Permissible Plate Materials and Allowable Stresses (SI)  
  Plate Material Plate  Specification Grade Nominal Plate Thickness t
mm 		Minimum Yield Strength
Mpa 		Minimum Tensile Strength
Mpa 		Product Design Stress Sd
Mpa 		Hydrostatic Test Stress St
Mpa 		   
A283 C
205 380
A285 C
205 380
A131 A
235 400
A131 B
235 400
A36 -
250 400
A131 EH36
360 490
A573 58
220 400
A573 65
240 450
A573 70
290 485
A516 55
205 380
A516 60
220 415
A516 65
240 450
A516 70
260 485
A662 B
275 450
A662 C
295 485
A537 1 t ≤ 65 345 485
A537 2 t ≤ 65 415 550
A633 C t ≤ 65 345 485
A633 D t ≤ 65 345 485
A678 A
345 485
A678 B
415 550
A737 B
345 485
A841 Class 1
345 485
  A841 Class 2   415 550  
 
  Table 5.2b—Permissible Plate Materials and Allowable Stresses (USC)  
  Plate Material Plate  Specification Grade Nominal Plate Thickness t
in. 		Minimum Yield Strength
psi 		Minimum Tensile Strength
psi 		Product Design Stress Sd
psi 		Hydrostatic Test Stress St
psi 		 
A283 C
30.000 55.000
A285 C
30.000 55.000
A131 A
34.000 58.000
A131 B
34.000 58.000
A36 -
36.000 58.000
A131 EH36
51.000 71.000
A573 58
32.000 58.000
A573 65
35.000 65.000
A573 70
42.000 71.000
A516 55
30.000 55.000
A516 60
32.000 60.000
A516 65
35.000 65.000
A516 70
38.000 70.000
A662 B
40.000 65.000
A662 C
43.000 70.000
A537 1 t ≤ 2-½ 50.000 70.000
A537 2 t ≤ 2-½ 60.000 80.000
A633 C t ≤ 2-½ 50.000 70.000
A633 D t ≤ 2-½ 50.000 70.000
A678 A
50.000 70.000
A678 B
60.000 80.000
A737 B
50.000 70.000
A841 Class 1
50.000 70.000
  A841 Class 2   60.000 80.000