Document Text Contents
Page 1
--- Reproduced By GLOBAL
&@ ENGINEERING DOCUMENTS - - With The Permission Of API
Under Royalty Agreement - 7- --
Manual of Petroleum
Management Standard
Chapter 2-Tank Calibration
Section 2A-Measurement and Calibration of
Upright Cylindrical Tanks by the
Manual Tank Strapping Method
FIRST EDITION, FEBRUARY 1995
1 Reaffirmed 3/2002
American Petroleum Institute
1220 L Street, Northwest
Washington, D.C. 20005
11’
Page 2
STEP
One of the most significant long-term trends affecting the future vitality of the petroleum
industry is the public’s concerns about the environment. Recognizing this trend. APl mem-
ber companies have developed a positive, forward looking strategy called STEP: Strategies
for Today’s Environmental Partnership. This program aims to address public concerns by
improving industry’s environmental, health and safety performance; documenting perfor-
mance improvements; and communicating them to the public. The foundation of STEP is
the API Environmental Mission and Guiding Environmental Principles. API standards, by
promoting the use of sound engineering and operational practices, are an important means
of implementing API’s STEP program.
API ENVIRONMENTAL MISSION AND GUIDING
ENVIRONMENTAL PRINCIPLES
The members of the American Petroleum Institute are dedicated to continuous efforts to
improve the compatibility of our operations with the environment while economically de-
veloping energy resources and supplying high quality products and services to consumers.
The members recognize the importance of efficiently meeting society’s needs and our re-
sponsibility to work with the public, the government, and others to develop and to use nat-
ural resources in an environmentally sound manner while protecting the health and safety
of our employees and the public. To meet these responsibilities, API members pledge to
manage our businesses according to these principles:
To recognize and to respond to community concerns about our raw materials, products
and operations.
To operate our plants and facilities, and to handle our raw materials and products in a
manner that protects the environment, and the safety and health of our employees and the
public.
To make safety, health and environmental considerations a priority in our planning. and
our development of new products and processes.
To advise promptly appropriate officials, employees, customers and the public of infor-
mation on significant industry-related safety, health and environmental hazards, and to
recommend protective measures.
To counsel customers, transporters and others in the safe use, transportation and disposal
of our raw materiais, products and waste materiais.
To economically develop and produce natural resources and to conserve those resources
by using energy efficiently.
To extend knowledge by conducting or supporting research on the safety, health and en-
vironmental effects of our raw materials, products, processes and waste materials.
To commit to reduce overall emissions and waste generation.
To work with others to resolve problems created by handling and disposal of hazardous
substances from our operations.
To participate with government and others in creating responsible laws. regulations and
To promote these principles and practices by sharing experiences and offering assistance
to others who produce, handle. use, transport or dispose of similar raw materials, petro-
leum products and wastes.
standards to safeguard the community. workplace and environment.
Page 34
MEASUREMENT AND CALIBRATION OF UPRIGHT CYLINDRICAL TANKS 25
2.2A.19.4.4 The Tape-Rise Correction Equation for Lap
Joints is as follows:
a. Application of Equation 3 in modified form to tape rise at
lapjoints is described with reference to Figure 17. In Figure
17, the locations of the plates in the lap joint are shown as
positioned by the plates in the rings above and below the lap
joint. The position of the plate in the ring if no joint existed
is shown by the broken lines in relation to the plates in the
lap joint.
b. The circumference as measured over the lap joint should
be corrected to the true circumferential path the tape would
take if no joint existed. As shown in Figure 17, this requires
correction for only one-half of the tape rise. With the width,
w, eliminated, the equation becomes:
8N t
Deduction (inches) = 3 2 .Jr/2d (4)
- 4 N t (5 )
- -xl l t /2d
3
c. It is also shown in Figure 17 that no deductions for dead-
wood at lap joints are required, since the deductible and
additive volumes at lap joints are equal.
2.2A.19.5 EXPANSION AND CONTRACTION OF
STEEL TANK SHELLS DUE TO LIQUID
HEAD
2.2A.19.5.1 Expansion and contraction of steel tank
shells due to liquid head shall be taken into consideration.
Gauge
Hatch
Pontoon
Emergency
Drain
Vent
-u- - -
U
This adjustment need not be made for tanks with a capacity
of less than 500 barrels.
2.2A.19.5.2 The effect of liquid head may be introduced
into the capacity table in the following ways:
a. Reduce strapped circumferences to zero stress condition
by using equation 6 (see 2.2A.19.5.3) and by applying
expansion effects of progressively increasing liquid levels at
successive course levels.
b. By strapping the tank with maximum liquid level and
destressing the tank by courses for decreasing liquid levels.
2.2A.19.5.3 Field circumference measurements shall be
adjusted to ?empty tank? or unstressed basis. Then the
volume calculations should proceed with volumes adjusted
to show progressively increasing capacity, including expan-
sion effects, at successively higher levels by rings. Strapped
circumferences should be corrected to zero stress condition
by means of the following equation:
-WhC2
AC=------
2nEt
Where:
AC = circumference correction to empty tank or
unstressed condition.
W = weight of liquid per unit volume.
h = liquid head above strapped elevation.
C = strapped circumference before correction.
E = modulus of elasticity of metal in tank shell.
t = shell thickness at strapped elevation.
Note: All units must be consistent. For example, in the customary system,
AC, C, h, and t may be in inches; W , in pounds per cubic inch; and E in
Center of Roof \1
I
Drain
- - -
Figure 1 &Typical Steel Pontoon Floating Roof with Single Center Deck
Page 35
26 CHAPTER 2, SECTION 2A
tat Which Shell Departs
Scribed Circle
Outside Circle of Tank or Path
of Tape When Corrected
Capacity to be Deducted From Tank
Actual Tape Rise
One Half Plate
Thickness
Line of Scribed Circle
Capacity to be Added to Tank
Point at Which Shell Departs
from Scribed Circle Plate Thickness
Figure 17-True Circumference Versus Tape Path at Axial
Lap Joint Away from Circumferential Joint
Page 67
1-01 l(a-2/95-lM (1E)
Page 68
American Petroleum Institute
1220 L Street, Northwest
Order No. 852-022A1
--- Reproduced By GLOBAL
&@ ENGINEERING DOCUMENTS - - With The Permission Of API
Under Royalty Agreement - 7- --
Manual of Petroleum
Management Standard
Chapter 2-Tank Calibration
Section 2A-Measurement and Calibration of
Upright Cylindrical Tanks by the
Manual Tank Strapping Method
FIRST EDITION, FEBRUARY 1995
1 Reaffirmed 3/2002
American Petroleum Institute
1220 L Street, Northwest
Washington, D.C. 20005
11’
Page 2
STEP
One of the most significant long-term trends affecting the future vitality of the petroleum
industry is the public’s concerns about the environment. Recognizing this trend. APl mem-
ber companies have developed a positive, forward looking strategy called STEP: Strategies
for Today’s Environmental Partnership. This program aims to address public concerns by
improving industry’s environmental, health and safety performance; documenting perfor-
mance improvements; and communicating them to the public. The foundation of STEP is
the API Environmental Mission and Guiding Environmental Principles. API standards, by
promoting the use of sound engineering and operational practices, are an important means
of implementing API’s STEP program.
API ENVIRONMENTAL MISSION AND GUIDING
ENVIRONMENTAL PRINCIPLES
The members of the American Petroleum Institute are dedicated to continuous efforts to
improve the compatibility of our operations with the environment while economically de-
veloping energy resources and supplying high quality products and services to consumers.
The members recognize the importance of efficiently meeting society’s needs and our re-
sponsibility to work with the public, the government, and others to develop and to use nat-
ural resources in an environmentally sound manner while protecting the health and safety
of our employees and the public. To meet these responsibilities, API members pledge to
manage our businesses according to these principles:
To recognize and to respond to community concerns about our raw materials, products
and operations.
To operate our plants and facilities, and to handle our raw materials and products in a
manner that protects the environment, and the safety and health of our employees and the
public.
To make safety, health and environmental considerations a priority in our planning. and
our development of new products and processes.
To advise promptly appropriate officials, employees, customers and the public of infor-
mation on significant industry-related safety, health and environmental hazards, and to
recommend protective measures.
To counsel customers, transporters and others in the safe use, transportation and disposal
of our raw materiais, products and waste materiais.
To economically develop and produce natural resources and to conserve those resources
by using energy efficiently.
To extend knowledge by conducting or supporting research on the safety, health and en-
vironmental effects of our raw materials, products, processes and waste materials.
To commit to reduce overall emissions and waste generation.
To work with others to resolve problems created by handling and disposal of hazardous
substances from our operations.
To participate with government and others in creating responsible laws. regulations and
To promote these principles and practices by sharing experiences and offering assistance
to others who produce, handle. use, transport or dispose of similar raw materials, petro-
leum products and wastes.
standards to safeguard the community. workplace and environment.
Page 34
MEASUREMENT AND CALIBRATION OF UPRIGHT CYLINDRICAL TANKS 25
2.2A.19.4.4 The Tape-Rise Correction Equation for Lap
Joints is as follows:
a. Application of Equation 3 in modified form to tape rise at
lapjoints is described with reference to Figure 17. In Figure
17, the locations of the plates in the lap joint are shown as
positioned by the plates in the rings above and below the lap
joint. The position of the plate in the ring if no joint existed
is shown by the broken lines in relation to the plates in the
lap joint.
b. The circumference as measured over the lap joint should
be corrected to the true circumferential path the tape would
take if no joint existed. As shown in Figure 17, this requires
correction for only one-half of the tape rise. With the width,
w, eliminated, the equation becomes:
8N t
Deduction (inches) = 3 2 .Jr/2d (4)
- 4 N t (5 )
- -xl l t /2d
3
c. It is also shown in Figure 17 that no deductions for dead-
wood at lap joints are required, since the deductible and
additive volumes at lap joints are equal.
2.2A.19.5 EXPANSION AND CONTRACTION OF
STEEL TANK SHELLS DUE TO LIQUID
HEAD
2.2A.19.5.1 Expansion and contraction of steel tank
shells due to liquid head shall be taken into consideration.
Gauge
Hatch
Pontoon
Emergency
Drain
Vent
-u- - -
U
This adjustment need not be made for tanks with a capacity
of less than 500 barrels.
2.2A.19.5.2 The effect of liquid head may be introduced
into the capacity table in the following ways:
a. Reduce strapped circumferences to zero stress condition
by using equation 6 (see 2.2A.19.5.3) and by applying
expansion effects of progressively increasing liquid levels at
successive course levels.
b. By strapping the tank with maximum liquid level and
destressing the tank by courses for decreasing liquid levels.
2.2A.19.5.3 Field circumference measurements shall be
adjusted to ?empty tank? or unstressed basis. Then the
volume calculations should proceed with volumes adjusted
to show progressively increasing capacity, including expan-
sion effects, at successively higher levels by rings. Strapped
circumferences should be corrected to zero stress condition
by means of the following equation:
-WhC2
AC=------
2nEt
Where:
AC = circumference correction to empty tank or
unstressed condition.
W = weight of liquid per unit volume.
h = liquid head above strapped elevation.
C = strapped circumference before correction.
E = modulus of elasticity of metal in tank shell.
t = shell thickness at strapped elevation.
Note: All units must be consistent. For example, in the customary system,
AC, C, h, and t may be in inches; W , in pounds per cubic inch; and E in
Center of Roof \1
I
Drain
- - -
Figure 1 &Typical Steel Pontoon Floating Roof with Single Center Deck
Page 35
26 CHAPTER 2, SECTION 2A
tat Which Shell Departs
Scribed Circle
Outside Circle of Tank or Path
of Tape When Corrected
Capacity to be Deducted From Tank
Actual Tape Rise
One Half Plate
Thickness
Line of Scribed Circle
Capacity to be Added to Tank
Point at Which Shell Departs
from Scribed Circle Plate Thickness
Figure 17-True Circumference Versus Tape Path at Axial
Lap Joint Away from Circumferential Joint
Page 67
1-01 l(a-2/95-lM (1E)
Page 68
American Petroleum Institute
1220 L Street, Northwest
Order No. 852-022A1
