API 650 STORAGE TANK VERSUS RECTANGULAR TANK

API 650 STORAGE TANK RECTANGULAR TANK

Design Code and Design based on API STD 650 and as a Design based on Roark's formula for stress
Specification supplementary based on PTS 12.22.02. & strain and as a supplementary based on
Calculated by using the First‐Foot Method PTS 12.22.09. Calculated by using
formulas for plat plates with straight
boundaries and constant thickness
(Chapter 11, Table 11.4 of Roark's formula
7th edition)
Acceptance Criteria PTS 12.22.02 clause 2.2.1, the open top PTS 12.22.09 clause 1.1.3, Rectangular
tank (with no roof) may be used for tanks can be used for storage of
storage of water services when water hydrocarbons, chemicals, water, and
purity is not a concern. By refer this other liquids. Rectangular tanks shall not
statement, API 650 tank with a cone roof be used for sour, hydrogen, toxic, and
can be used in water quality service. (i.e. lethal services. By referring to this
RO system.) statement, a Rectangular tank can be used
in water service.
Tank Size and Based on Detail Feasibility Study, DFS Based on volume from the API 650 tank,
Volume report, the size of UF Permeate, RO the size of the rectangular tank can be
Permeate, and RO rejection tank is almost assumed as 3m (L) x 3m (W) x 4m (H).
with 3m I.D x 5m in Height. Based on this (See attachment 1)
size, the volume is approximately 35.34
cubic meters. (See attachment 1)
Materials The proposed material is carbon steel The proposed material is carbon steel
with a 3.0mm corrosion allowance. This with a 3.0mm corrosion allowance. This
material and corrosion allowance are used material and corrosion allowance are used
for the preliminary thickness calculation. for the preliminary thickness calculation.

Thickness Based on the First‐Foot Method Based on the Roark's formula calculation
(Preliminary) calculation (See attachment 2) and by (see attachment 3) and by considering the
considering the 3.0mm corrosion 3.0mm corrosion allowance, the required
allowance, the required thickness for the thickness for the tank wall is 10.0mm with
tank wall is 6.35mm without any stiffener. a stiffener ring (vertical and horizontal) at
every 500mm spacing. Sketch for stiffener
(see attachment 4) .
Space Based on the site visit, the space available Based on the site visit, the space available
is sufficient. The advantage of this type of is sufficient. The dimension of each tank
tank is the size of I.D can be reduced and panel (HxW, LxH & WxL) shall be designed
the height can be increased maintain the in the almost same dimension. If Length is
volume if the space is insufficient. designed higher than Width, the ratio of
a/b in Roark's formula calculation will be
higher and will affect the increment of the
thickness or stiffener.
Fabrication, Non‐ Due to the small size in I.D, the tank can This type of tank commonly fabricated at
Destructive be fabricated at the manufacturer's shop manufacturer's shop. With a stiffener,
Examination (NDE) instead of erection at the site. Without Non‐Destructive Examination on this tank
and Cost stiffener, Non‐Destructive Examination on is quite complicated which is required for
this tank is simple which is required for every single weld of stiffener, vertical &
major weld seam (i.e. circ. & Long). The horizontal (each 500mm spacing as
cost for each tank is approximately RM required by calc.). The cost is approx. RM
225,000 (See attachment 5) 345,000 (see attachment 5)
ATTACHMENT 1
 DOC. NO. : CALC-VOLUME
TANK VOLUME CALCULATION
REVISION: PRELIM

DATE: 12/04/22

PAGE : 1 of 2
MECIP (M) SDN BHD

01. UF PERMATE TANK

Based on DFS report, the propose type of the tank is cylindircal.
The preliminary size are as below.
Inside Diameter, D : 3m
Inside Radius, R : 1.5 m
Height, H : 5m

Volume, V : πR2H
3
= 35.34 m

Convert to Rectangular Tank

Length, L : 3m Note: ≤ 3m due to space
Width, W : 3m Note: ≤ 3m due to space
Height, H : 4m

Volume, V : LxWxH
3
= 36.00 m

02. RO REJECTION TANK

Based on DFS report, the propose type of the tank is cylindircal.
The preliminary size are as below.
Inside Diameter, D : 2.8 m
Inside Radius, R : 1.4 m
Height, H : 5m

Volume, V : πR2H
3
= 30.79 m

Convert to Rectangular Tank

Length, L : 3m Note: ≤ 3m due to space
Width, W : 3m Note: ≤ 3m due to space
Height, H : 3.4 m

Volume, V : LxWxH
3
= 30.60 m
 DOC. NO. : CALC-VOLUME
TANK VOLUME CALCULATION
REVISION: PRELIM

DATE: 12/04/22

PAGE : 2 of 2
MECIP (M) SDN BHD

03. RO PERMATE TANK

Based on DFS report, the propose type of the tank is cylindircal.
The preliminary size are as below.
Inside Diameter, D : 2.8 m
Inside Radius, R : 1.4 m
Height, H : 4.7 m

Volume, V : πR2H
3
= 28.94 m

Convert to Rectangular Tank

Length, L : 3m Note: ≤ 4m due to space
Width, W : 3m Note: ≤ 4m due to space
Height, H : 3.4 m

Volume, V : LxWxH
3
= 30.60 m
ATTACHMENT 2
 DOC. NO. : CALC-API 650
API 650 TANK CALCULATION
REVISION: PRELIM

DATE: 12/04/22

PAGE : 1 of 3
MECIP (M) SDN BHD

1.0 Tank Design Data

Design Code : API STD. 650, 2007 EDITION + 2011 ADD
Client's Specs. : ‐
Equipment Name : FEED TANK

Equipment Tag No. : ‐

Type of Tank Roof : SELF‐SUPPORTING CONE ROOFS

Slope of Tank Roof, ɵ : 15 deg = 0.2618 rad

Note: 9.5 º ≤ ɵ ≤ 37 º as per API STD 650, 2007 Edition + 2011 Add., clause 5.10.5.1

Material of Construction
Shell, Bottom & Roof Plate : A 516 GR 70
Stiffener (Angle) : A 36
Nozzle : A 106 GR B
Fluid /Contents : ‐

Int. Design Pressure, P i : 15 kPa = 2.18 Psi

Ext. Design Pressure, P e : 0.60 kPa = 0.09 Psi
Design Temperature, T d : 85 ºC
Operating Pressure, P o : 0.00 kPa
Operating Temperature, T o : 40 ºC
Inside Diameter of Tank, d i : 3000 mm = 3 m
Height of Tank, h : 5000 mm = 5 m
Design Liquid Level, H = 5000 mm = 5 m
Nominal Tank Diameter, D : 3006.35 mm = 3.00635 m
Outside Diameter of Tank, d o : 3012.70 mm = 3.0127 m
Corrosion Allowance, CA : 3.00 mm = 0.003 m
Density of Contents, ρ : 1051 kg/m3
Specific Gravity of Contents, G = 1.051
Joint Efficiency, E : 0.7

Ground Snow Load, S : 0.00 kPa

Balanced Design Snow Load, S b : 0.00 kPa
Unbalanced Design Snow Load, S u : 0.00 kPa
Live Load, L r : 1.00 kPa
Design Wind Code, V : ASCE‐7
Design Wind Speed, V : 190 km/hr
 DOC. NO. : CALC-API 650
API 650 TANK CALCULATION
REVISION: PRELIM

DATE: 12/04/22

PAGE : 2 of 3
MECIP (M) SDN BHD

4.0 Shell Plate Design

4.1 Shell Thickness Calculation, 1‐Foot Method
As per API STD 650, 2007 Edition + 2011 Add., clause 5.6.3.2 or App. S, clause S.3.2.2.3)

Numbers of Course, n : 3 nos

For 1 st Shell Course (Bottom)

Course Width, W 1 = 2438 mm
Liq. Level consider for 1st Course, H = 5000 mm = 5m

Reqd. Design Shell Thickness, t d : 4.9D(H‐0.3)G + CA

Sd xE
= 4.9 * 3.006 ( 5.00 ‐ 0.3 )1.1 + 3.0
174 * 0.7
= 3.29 mm

Reqd. Hydro‐test Shell Thickness, t t : 4.9D(H‐0.3)G

St xE
= 4.9 * 3.006 ( 5.00 ‐ 0.3 )1.1
197 * 0.7
= 0.26 mm

For 2 nd Shell Course (Middle)

Course Width, W 2 = 2438 mm
Liq. Level consider for 2nd Course, H = 2562 mm = 2.562 m

Reqd. Design Shell Thickness, t d : 4.9D(H‐0.3)G + CA

Sd xE
= 4.9 * 3.006 ( 2.56 ‐ 0.3 )1.1 + 3.0
174 * 0.7
= 3.14 mm

Reqd. Hydro‐test Shell Thickness, t t : 4.9D(H‐0.3)G

St xE
= 4.9 * 3.006 ( 2.56 ‐ 0.3 )1.1
197 * 0.7
= 0.12 mm

For 3 rd Shell Course (Top)

Course Width, W 3 = 618 mm
Liq. Level consider for 3rd Course, H = 618 mm = 0.618 m
 DOC. NO. : CALC-API 650
API 650 TANK CALCULATION
REVISION: PRELIM

DATE: 12/04/22

PAGE : 3 of 3
MECIP (M) SDN BHD

Reqd. Design Shell Thickness, t d : 4.9D(H‐0.3)G + CA

Sd xE
= 4.9 * 3.006 ( 0.62 ‐ 0.3 )1.1 + 3.0
174 * 0.7
= 3.02 mm

Reqd. Hydro‐test Shell Thickness, t t : 4.9D(H‐0.3)G

St xE
= 4.9 * 3.006 ( 0.62 ‐ 0.3 )1.1
197 * 0.7
= 0.02 mm

4.2 Summary of Shell Plate Thickness

Plate Req. Design Used

Width of
Course No. Design Allowable H (m) Thickness Thickness
Material Course (mm)
Stress (Mpa) (mm) (mm)
1 A 516 GR 70 174 2438 5 3.29 6.35
2 A 516 GR 70 174 2438 2.562 3.14 6.35
3 A 516 GR 70 174 618 0.124 3.02 6.35
Note: As per clause 5.6.1.1, the required shell thickness shall be the greater of the design shell
thickness, including any corrosion allowance, or the hydrostatic test thickness, but the shell
thickness shall not be less than the following:

Nominal Tank Diameter (m) Nominal Plate Thickness (mm)

< 15 5
15 to < 36 6
36 to 60 8
> 60 10

Thickness Shell Plate, t s = 6.35 mm = 0.00635 m

Area of Shell Plate, A s : π*D *h

= 3.142 * 3,006.35 * 5,000
= 47223635.37 mm2 = 47.224 m
2

Volume of Shell Plate, v s : As*ts

= 47.224 * 0.00635
= 0.300 m3

Shell Plate Weight, D LS : vs* ρm

= 0.300 * 7,750
= 2323.99 kg = 22798.37 N
ATTACHMENT 3
 DOC. NO. : CALC-RECT. TANK
RECTANGULAR TANK CALCULATION
REVISION: PRELIM

DATE: 12/04/22

PAGE : 1 of 3
MECIP (M) SDN BHD

2.0 SIDE WALL THICKNESS CALCULATION

Tank Name : UF Permate Tank
Tag Number : -
Design Code : Roark's & Young Formula
Material : SA 36
Height of Tank, H : 4000 mm = 157.48 in
Width of Tank, W : 3000 mm = 118.11 in
Length of Tank, L : 3000 mm = 118.11 in
Specific Gravity of Liquid, Sg : 1
3
Density of Liquid, ρ : 1000 kg/m

Design Pressure, Dp : Full Water + 0 mm

o
Design Temperature, Dt : 40 C
Corrosion Allowance,Ca : 3 mm = 0.12 in
Allowable Stress, Sa : 114.457N/mm2 = 16601 psi
Yield Stress, Sy : 230.184N/mm2 = 33385 psi
Modulus of Elasticity, E : 199459 N/mm2 = 28929134 psi

Internal Pressure due to Full Water, q : ρxgH

= 39240 N/m2 = 5.6898 psi

3 3
Volume of Tank,V = 3.6E+10 mm = 1271.16 ft

Load Diagram

2.1 Shell Plate Thickness Calculation

( Ref: Roark's Formula for Stress and Strain Seven Edition)

Chapter 11[Table 11.4 (9a): Rectangular Plate, 3 fixed, 1 simply support load - Uniform entire plate &
Table 11.4 (6a): Rectangular Plate, 2 long edges fixed, 2 short edges simply support.

a) For Section A and B (Table 11.4 6(a))

Interpolation of Constant Value β and α

Ratio W/(H/3) 1 1.2 1.4 1.6 1.8 2 ∞

β 0.4182 0.4626 0.486 0.4968 0.4971 0.4973 0.5
α 0.021 0.0243 0.0262 0.0273 0.028 0.0283 0.0285
Table 1
 DOC. NO. : CALC-RECT. TANK
RECTANGULAR TANK CALCULATION
REVISION: PRELIM

DATE: 12/04/22

PAGE : 2 of 3
MECIP (M) SDN BHD

H1~H8 = H/8
= 500.00 mm
= 19.69 in
W1~W6 = W/6
= 500.00 mm
= 19.69 in
W1~6/H1~8 = 1.00

From Table 1(Interpolation)

β 0.4182
α 0.021

Required Plate thickness, t = SQRT (‐βqHmax2/Sa) + Ca

= 0.35 in
= 8.99 mm

b) For Section C(Table 11.4 9(a))

Interpolation of Constant Value β and α

Ratio W/(H/3) 0.25 0.5 0.75 1 1.5 2 3

β1 0.02 0.081 0.173 0.307 0.539 0.657 0.718
β2 0.004 0.018 0.062 0.134 0.284 0.37 0.422
β3 0.016 0.061 0.118 0.158 0.164 0.135 0.097
β4 0.031 0.121 0.242 0.343 0.417 0.398 0.318
 0.115 0.23 0.343 0.453 0.584 0.622 0.625
 0.123 0.181 0.253 0.319 0.387 0.397 0.386
 0.125 0.256 0.382 0.417 0.547 0.549 0.53
Table 2

W1~6/H1~8 = 1.00

From Table 2(Interpolation)

β1 0.307
β2 0.134
β3 0.158
β4 0.343
 0.453
 0.319
 0.417

Required Plate thickness, t = SQRT (‐β1qHmax2/Sa) + Ca

= 0.32 in
= 8.13 mm

Actual Choose Plate thickness, ta = 10 mm = 0.39370079 in

 DOC. NO. : CALC-RECT. TANK
RECTANGULAR TANK CALCULATION
REVISION: PRELIM

DATE: 12/04/22

PAGE : 3 of 3
MECIP (M) SDN BHD

2.2 Maximum Reaction Force per Unit Length Normal to Plate Surface.
( Ref: Roark's Formula for Stress and Strain Seven Edition)
R = qHmax
= 50.74 lb/in
= 8.89 N/mm

2.3 Maximum Plate Deflection

( Ref: Pressure Vessel Handbook Twelfth Edition- Rectangular Tank)

Interpolation of Constant Value β and α

Ratio (H/3)/W 0.25 0.286 0.333 0.4 0.5 0.667 1

β 0.024 0.031 0.041 0.056 0.08 0.116 0.16
α 0.00027 0.00046 0.00083 0.0016 0.0035 0.0083 0.022

Ratio (H/3)/W 1.5 2 2.5 3 3.5 4

β 0.26 0.34 0.38 0.43 0.47 0.49
α 0.043 0.06 0.07 0.078 0.086 0.091
Table 3

H1~8/W1~6 = 1.00

From Table 3(interpolation)

β 0.16
α 0.022

Max. Deflection of plate, ymax = (α x0.036SgHmaxW4)/Eta3

= 0.001 in
0.034 mm
Acceptance Criteria
1.Maximum Allowable Deflection are Limited to 1/2 Thickness. = 5 mm
2.Maximum Deflection of Plate are Limited to W/300 = 1.67 mm

Max. Deflection plate is less than Acceptance critria, Plate thickness is Sufficient

2.4 Stiffening Frame

( Ref: Pressure Vessel Handbook Twelfth Edition- Rectangular Tank)

Min. required moment of Inertia of Stiffening

4
I = ( RL )/(192 Eta)
4
= 0.003 in
4
= 1450 mm

Choose Stiffener = 10 x 50

Moment Inertia of Stiffener = (th3)/12

4
= 104167 mm

Moment Inertia of Stiffener is higher than required, Stiffener used is Adequate

ATTACHMENT 4
ATTACHMENT 5
Muhamad Faizol

From: Mohamad Buhori Bin Fauzi <Buhori@oscmalaysia.com>

Sent: Tuesday, 12 April, 2022 11:29 AM
To: Muhamad Faizol
Subject: RE: P21436-MRCSB; RFQ for API 650 Storage Tank & Rectangular Tank

Dear Mr. Faizol.

We are please to submit our price proposal as follows :

1. Cylindrical tank as per API 650, 3000 mm ID x 5000 mm Height : RM 255,000.00 (Delivery 22 weeks DAP
MRCSB Melaka)
2. Rectangular tank, 3000 mm L x 3000 mm W x 4000 mm H : RM 345,000.00 ( (Delivery 24 weeks DAP MRCSB
Melaka)

FYI, both tanks is manageable to fabricate inside our workshop.

Even though both tanks having about the same in term of volume, but material and fabrication wise, rectangular
tank require more material compared to cylindrical tank. While for fabrication, rectangular tank required longer
time to fabricate due to difficulties and large numbers of stiffener ring required outside of the tank wall.

Thank you.

Regards,
Buhori

From: Muhamad Faizol <faizol@mecipglobal.com.my>

Sent: Tuesday, 12 April, 2022 10:29 AM
To: Mohamad Buhori Bin Fauzi <Buhori@oscmalaysia.com>
Subject: P21436‐MRCSB; RFQ for API 650 Storage Tank & Rectangular Tank
Importance: High

CAUTION: This email originated from outside Oilfields Supply Center Ltd. Exercise caution when
opening attachments or clicking links, especially from unknown senders.
Assalam Tuan Buhori,
We received RFQ from MRCSB to perform the Basic Engineering Design for the RO‐EDI system design improvement
project. The equipment involves in this project is a storage tank (either API 650 or a rectangular tank). In regard to
this matter, we would like to know the budgetary based on the type and the size of tank as attached.

Thanks in advance.
Faizol
012‐9574874
Mecip Global Engineers Sdn. Bhd.

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