The document provides information on storage tank design based on API 650 standards. It discusses the different types of storage tanks including their shapes, sizes, and applications. The two main types are atmospheric storage tanks and pressurized storage tanks. Cylindrical tanks are the most common and can have different roof types like fixed, floating, or cone/dome roofs depending on the stored liquid's flash point. Material selection, tank capacities, accessories, foundations, and important notes about containment are also covered.

1. STORAGE TANK DESIGN
based on API 650 Ed. 12 Add. 3
By :
Izzatul F
TANK INTRODUCTION

2. STORAGE TANK
1
Storage tanks are available in many shapes: vertical and horizontal cylindrical;
open top and closed top; flat bottom, cone bottom.
Large tanks tend to be vertical cylindrical, or to have rounded corners to easier
withstand hydraulic hydrostatically induced pressure of contained liquid
Raw Materials Intermediate products Final products
Recycle materials Off-grade materials Fuels
Storage Facility are
required for:

3. STORAGE TANK
2
The storage tanks can be divided into two basic types:
Atmospheric storage
Atmospheric storage is a term applied to tanks operating at or near atmospheric
pressure. This type of tank is used to hold liquid which will not vaporize at
ambient temperature. Tanks used in this category are primarily the open top,
fixed roof (cone & dome) and floating roof.
Pressurized storage
Pressurized storage applies to those vessels (mounded bullets) which are
designed to withstand pressure sufficient to keep the liquid stored, from
vaporizing. High vapor pressure hydrocarbons such as propane and butane are
the types of products requiring pressurized storage vessels (Mounded Bullets)

4. API 650 TANK STANDARD
3
Content
Section 1 - Scope
Section 2 - Normative Reference
Section 3 - Terms and Definition
Section 4 - Materials
Section 5 - Design
Section 6 - Fabrication
Section 7 - Erection
Section 8 - Method of Examining Joints
Section 9 - Welding Procedure & Welder Qualification
Section 10 - Marking
Annex A - Y

5. API 650 TANK STANDARD
4
Scope
Establish minimum
Requirements for material,
design, fabrication, erection and
testing for above ground welded
storage tank in various sizes
and capacities for internal
pressure approximating
atmospheric pressure (internal
Pressure not exceeding the
weight of the roof plates)
Applies only to tanks whose
entire bottom is uniformly
supported
Tank in non refrigerated service
that have maximum design
temperature of 93 oC or less.
Limit
The face of the first flange in
bolted flanged connections,
unless covers or blinds are
provided as permitted in this
Standard
The first sealing surface for
proprietary connections or
fittings
The first threaded joint on the
pipe in a threaded connection to
the tank shell
The first circumferential joint in
welding-end pipe connections if
not welded to a flange.

6. STORAGE TANK
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Cylindrical Tank
A storage tank is a container,
usually for holding liquids,
sometimes for compressed
gases (gas tank).
Spherical Tank
Vertical or
Horizontal Tank

7. CYLINDRICAL TANK TYPE
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Based on roof type:
Cone Roof
Dome Roof
Fixed Roof
Umbrella Roof
1. Supported
2. Self
Supported

8. CYLINDRICAL TANK TYPE
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Supported type fixed roof
Inside Single Beam No Column
Outside Single Beam No Column
Inside Structure with Column
Outside Structure with Central Column
Inside Truss Structure without Center Column
Rafter Pattern on Inside
Rafter Pattern on Outside

9. CYLINDRICAL TANK TYPE
8
Based on roof type:
Internal Floating Roof
Floating Roof
External Floating Roof

10. CYLINDRICAL TANK TYPE
9
Floating Roof
FR tanks do not have a fixed
roof (it is open in the top) and
has a floating roof only.
Applications of FR tanks:
Medium flash point liquids such
as naphtha, kerosene, diesel,
crude oil etc. are stored in
these tanks.
IFR tanks are used for liquids
with low flash-points (eg.
gasoline, ethanol). These tanks
are nothing but cone roof tanks
with a floating roof (steel disc)
inside which travels up and
down along with the liquid level.
Floating roofs are supported
with legs on which they rest.

11. CYLINDRICAL TANK TYPE
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Floating Roof
Advantages of floating roof
tanks:
 Reduce material losses and
air pollution.
 Reduce fire and explosion
risk due to very small
vapour space.
Disadvantages:
 High cost.

12. CYLINDRICAL TANK
11
Roof Type Decision
• Fixed Roof Tank
Advantages : Easy to Construct
and cheap to build.
Disadvantages : Material Loses
due to escape of vapor.
• Floating Roof Tank
Developed to store volatile
liquids to minimize the loss of
valuable vapors, as well as, to
minimize the hazard of
dangerous vapor formation
underneath a fixed roof.

13. CYLINDRICAL TANK
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Roof Type Decision
Flash Point High Flash Point Medium Flash
Point
Low Flash Point
Fluid Example Fuel, Oil Naphtha, kerosene,
Diesel
Gasoline, Ethanol
Roof type Fixed Roof External Floating
Roof
Internal Floating
Roof
Lower Flash Point = Lower Specific Gravity

14. CYLINDRICAL TANK MATL
14
Main Material
Tank Part Carbon Steel Stainless Steel
Annular & Bottom
Shell
Roof
& etc from Plate
A 36
A 283 Gr. C
A 516 Gr. 70
A 573 Gr. 70 ….
A 240 Tp 304/L
A 240 Tp 316/L
Duplex
Nozzle Flange A 105 A 181 Gr. 304/L
A 181 Gr. 316/L
Nozzle Neck & Pipe A 106 Gr. B
A 53 Gr. B
A 312 Gr. 304/L
A 312 Gr. 316/L
Structure A 36 or SS 400 SUS
Bolting ASTM F1554 Galv
Welding Rod Ts 550 MPa & Ty 585 MPa
Gasket Spiral Wound / Non Asbestos

15. CYLINDRICAL TANK CAPACITY
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16. TANK ACCESSORIES
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Main Part
Floating Roof accessories
Roof Support
Opening & Venting
Tank Support
Access tank
Top Angle & stiffener
Drain & Overflow
Other accessories

17. TANK FOUNDATION
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Earth Foundation without Ring wall
• For Small tanks, foundation can consist of
compacted crushed stone, clan sand or similar
material.
Earth Foundation with Concrete Ring wall
• Large tanks with heavy or tall shell and/or self
supported roofs impose a substantial load on the
foundation under the shell.
Slab Foundation
• Common foundation For Large tanks
Elevated Foundation
• For Tanks which need gravity and/or leak detection
system

18. TANK FOUNDATION
18
• Checking Foundation
Surface, subsurface and climatic conditions vary from place to place, so it is not practical to
establish design data to cover all situations. The allowable soil loading and exact type of
subsurface construction to be used must be decided for each individual case after careful
consideration.
Foundation Elevation
Foundation Size & Roundness
Foundation Slope
Anchor Position (if any)

19. CYLINDRICAL TANK
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Important note:
 Since most liquids can spill, evaporate, or seep through even the smallest opening, special
consideration must be made for their safe and secure handling.
 This usually involves building a bunding, or containment dike, around the tank, so that any
leakage may be safely contained. In some cases these area is called the tank farm.

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