The document outlines the design specifications and calculations for a vertical tank as per API 650 guidelines, detailing parameters such as dimensions, materials, and capacities. It includes calculations for shell, bottom, and roof thicknesses, as well as venting requirements for both vacuum and pressure relief. The tank is designed to hold water with a total capacity of 125.04 m³ and is subject to specific operational criteria including filling and emptying rates.

1. TANK CACULATION
API 650 11th June 2007
TPHCM 15 Nov 2022

2. 1 DATA DESIGN
Design Code API 650 11th June 2007
Type Of Tank Vertical tank
Type Of Bottom Flat
Type Of Roof Cone roof
Stored Liquid Water
Specific gravity of the Liquid G = 1
Tank Internal Diameter D = 3990 mm
Height Of Tank Shell Ht = 10000 mm
Design Liquid Level Ht = 10000 mm
Normal Fill Level H = 9650 mm
Hydrostatic Fluid Level H = 9650 mm
Minimum Fill Level 235 mm
Tank Design Capacity 125.04 m3
Tank Operation Capacity 120.66 m3
Internal Design Pressure Pi = 0 bar (gauge)
Design External Pressure Pe = 0 bar (gauge)
Design Temprature 40 °C
PWHT None
Corrosion Allowance CA = 0 mm
Mateial SS304

3. 2 CALCULATION
2.1 Shell Thickness Calculation
Where
td = design shell thickness (mm)
tt = Hydrostatic test shell thickness (mm)
D = 4 Nominal diameter of tank (m)
H = design liquid level (m)
G = 1 specific gravity of the liquid to be stored
E = 0.7 joint efficiency (table S-4)
CA = - corrosion allowable (mm)
Sd = 155 allowable stress for the design condition (Mpa) (Table S-2a, S-2b)
St = 186 allowable stress for the hydrostatic test condition (Mpa) (Table S-2a, S-2b)
Ls = 1.5 Height of each course / wide of plate (m)
n = Number of course
tstd = Nominal thinkness listed in 5.6.1.1 except note 4
tsc = Thickness selected and used (refer S.3.2.1.1)
n H td tt tstd tcs Result
1st Course 1 10.0 1.7 1.5 5.0 5.0 OK
2nd Course 2 8.5 1.5 1.2 5.0 5.0 OK
3rd Course 3 7.0 1.2 1.0 5.0 5.0 OK
4th Course 4 5.5 0.9 0.8 5.0 5.0 OK
5th Course 5 4.0 0.7 0.6 5.0 5.0 OK
6th Course 6 2.5 0.4 0.3 5.0 5.0 OK
Last Course 7 1.0 0.1 0.1 5.0 5.0 OK
2.2 Bottom Thickness Calculation
Minimum thickness as per S.3.1.1 (tb1)
tb1 = 5 mm
Minimum thickness required tb = tb1 + CA
tb = 5 mm
Connection between the bottom plate and loweset course shell plate to be used Fillet Weld
Minimum size of Fillet Weld is 5mm
=
4.9 − 0.3
+
=
4.9 − 0.3

4. 2.3 Roof thickness design
Using self-support roof (5.10.5.1)
= 17.72 Degree (slope = 9:20)
Minimum thickness t = greates of
(2.3.1)
or
(2.3.2)
and 5 mm (2.3.3)
Where
D = 3.99 nominal diameter if the tank (m)
Dl = 0.40 Dead load of roof (kPa)
Pe = 0
Lr = 0.16 kPa
T = Dl+Pe+0.4.Lr = 0.46 kPa
U = Dl+Pe+0.4.Lr = 0.46 kPa
=> Minimum thickness t = greates of (2.3.1) = 1.25 or (2.3.2) = 1.09 or(2.3.3)= 5 mm
Selected t = 5.00 mm
2.4 Intermediate Wind Girders
Calculation for and installation of intermediate wind girders are not required for small tank
=
4.8 2.2
=
5.5 2.2

5. 2.5 Roof manhole
Table 5.13a, Figure 5.16
500 500 660 597 16 500 660 524 1050
Dia. Of
hole in
roof plate
Dp
Diameter of gasket
Inside Outside
Dia. Of
reinfocci
ng plate
Dr
Size of
manhole
Diameter of
neck
ID
Diameter of
cover plate
Dc
Diameter
of bole
circle
Db
Number of
Boles

6. 2.6 Roof venting
5.8.5.2 API 650 Normal venting shall meet the requirments specified in API Std 2000
Normal diameter, Di 3990 mm
Tank height, H 10000 mm
Design Capacity 125.04 m3
Design pressure, Pi 0 bar (gauge)
Boiling point (NBP) <149 °C
Design temprature 40 °C
Filling rate ( Pumping in/Flow rate to tank ), Vi 40 m3/h
20m3/h for RFC system
and 20 m3/h for city water supply
Emptying rate ( Pumping out/Flow rate from tank ), Vo 140 m3/h
40 m3/h for transfer pump / 2 pumps
60 m3/h for 5" outlet
40 m3/h for 4" outlet
Inbreathing (Vacuum Relief)
See table 1B, select 0.94 Nm3/h of air for each cubic meter per hour
Flow rate of free air Vfi = (T+273.15)/273.15*0.94*Vo = 150.87 m3/h
Thermal venting capacity requirment
From table 2B column 2a
Flow rate of free air Vti = (T+273.15)/273.15*33.7 = 38.64 m3/h
(select tank capacity is 200 cubic meters)
Total vacuum flow required, Vvi ( = Vfi + Vti ) = 189.51 m3/h
Outbreathing (pressure relieft)
See section 4.3.2.3.1, the requirment for venting capacity for maximum liquide movement
into tank with a normal boiling below 148.9 °C should be equivlant 2.02 Nm3/h per cubic
metrer per hour
Flow rate of free air Vfo = (T+273.15)/273.15*2.02*Vi = 43.11 m3/h
Thermal venting capacity requirment
From table 2B column 4c
Flow rate of free air Vto = (T+273.15)/273.15*33.7 = 33.70 m3/h
(select tank capacity is 200 cubic meters)
Total vacuum flow required, Vvo ( = Vfo + Vto ) = 76.81 m3/h

7. Open venting sizing
Maximum flow Q is greater Vvi ad Vvo = 189.51 m3/h
= 0.05 m3/s
Where
k = 0.7 Discharge coefficient (Figure 1)
A = cross sectional area of vent (m2)
g = 9.81 acceleration due to gravity (m/s2)
H = 10 Head as measure pressure differential (m)
p = 1 Air density (kg/m3)
= p.g = 9.81 Specific weight of Air (kg/m2s2)
=> A = 0.02 m2
= 16,815.45 mm2
Selected bleeder vent size 5" SCH40 6" SCH40 8" SCH40
Number of vent, N 1 1 1
Outside diameter of the vent, do 141 168 219 mm
Inside Dia. of one vent , di 134.5 161.5 211.6 mm
Total cross sectional area of vents, Av_actual 14,208 20,485 35,166 mm2
Safety ratio k = Av/A 0.84 1.22 2.09
Selected
= . . 2
=
. 2
=
2

8. 2.7 Opening hole
a. Shell manhole 20"( D500)
OD = 508 mm Outside diameter of shell manhole (Selected)
Bolts size M20x Figure 5-7A
Bolts hole 23 mm Bolts hole diameter
tn = 5 mm neck of manhole thickness (Table 5-4a)
t = 5 mm Compted above
T = 5 mm
Db = 667 mm Figure 5-8
Dc = 730 mm Figure 5-8
tc = 14 mm Thickness of shell manhole cover Plate (Table 5-3a)
tf = 14 mm Thickness of shell manhole Bolting flange (Table 5-3a)
b. Other opening holes
As per section S.3.3.1 the minimum thickness of connections and openings shall be as table
Size of nozzle Minimum Nominal Neck Thickness
NPS 2 and less Schedule 80
NPS 3 and NPS 4 Schedule 40
Over NPS4 6 mm