API 653 LATEST EXAM WITH
CORRECT ANSWERS
2025
API publications
necessari
ly address problems of what type? - correct answers - Problems of a
general nature. (Special notes section)
API Standard 653 covers in service steel tanks built to what standards? -
correct answers - This standard covers steel storage tanks built to API 650
and its predecessor API 12C. (1.1.1)
What API Standard always governs for tanks that have been placed in
service? -
correct answers - In the case of apparent conflicts between the
requirements of this standard and API 650 or its predecessor API 12C, API
653 shall govern for tanks that have been placed in service. (1.1.2)
API Standard 653 employs the design principles of what standard? -
correct answers - This standard employs the principles of API 650. (1.1.3)
When design and construction details are not given and are not available
in the standard to which the in service tank was originally constructed,
then details that will provide a level of integrity equal to the level provided
by the current edition of which standard must be used? - correct
answers - The current edition of API 650 must be used. (1.1.5)
Who has the ultimate responsability for complying with the provisions of
API653?
- correct answers - The owner/operator. (1.2)
The inspector agency of the jurisdiction in which the above ground is
storage tank is operated is called what? - correct answers - Authorized
inspection agency (3.3)
An employee of an authorized inspection agency certified as an AST
inspector per API 653 Appendix D, is known as what? - correct answers -
Authorized inspector (3.4)
What is the total metal loss divided by the period of time over which
the metal loss occurred? - correct answers - Corrosion rate (3.9)
What is the definition of a "repair" to a tank? - correct answers - Work
necessary to maintain or restore a tank to a condition suitable for safe
operation. (3.24)
, What must be done when the results of a tank inspection show that a
change has occurred from the original physical condition of that tank?
- correct answers - An evaluation shall be made to determine its
suitability for continued use. (4.1.1)
What must be done when the cone roof tank roof plates corrode to an
average thickness of less than 0.09" in any 100 in^2 area? - correct
answers - Shall be repaired or replaced. (4.2.1.2)
What section of API 653 must be considered when changing the service of
a tank to operation at temperatures above 200F? - correct answers -
All requirements of API 650, Appendix M. (4.2.4.3)
What form of corrosion does not normally represent a significant threat to
the overall structural integrity of the tank shell unless it is present in a
severe and numerous form?
- correct answers - Pitting (4.3.1.3)
When can widley scattered pits inside the tank shell be ignored? - correct
answers - Provided that:
a) no pit depth results in the remaining shell thickness being less than
one-half the
minimum acceptable tank shell
thickness exclusive of the corrosion allowance; and
b)the sum of their dimensions along any vertical line does not exceed 2
in. in an 8-in. length (see Figure 4.2). (4.3.2.2).
A tank of a single butt-weld with a back-up bar construction, built to an
unknownstandard in 1940 is inspected. Corrosion is general and an
evaluation of the tank's minimum thickness is required. What joint factor
would you use? - correct
answers - E = 0.85. (Table 4.2)
What can foundation settlement cause to appear in the shell of an AST?-
correct answers - Shell distortions. (4.3.5.2, 4.3.5.3)
Unless a stress analysis is performed what is the minimum bottom plate
thickness in the critical zone of the tank bottom? - correct answers - the
smaller of one-half the original bottom plate thickness or 50 % of tmin of the
lower shell course, but not less than 0.1 in. (4.4.5.4)
An AST operating at 250F is evaluated for continuing service. The inspector
checks the tank records and finds that the tank was originally built of ASTM
A516 gr60. What allowable stress should the inspector use in evaluation the
minimum thicknesses of the tank's shell? - correct answers - 32,000 * 0.80
= 25,600 (4.3.10.1.1a or Table 4.1)
A six year old storage tank is inspected. The tank has a diameter of 125
feet and its maximum liquid level height is 40 feet. The tank was
constructed of ASTM A283 gr C
CORRECT ANSWERS
2025
API publications
necessari
ly address problems of what type? - correct answers - Problems of a
general nature. (Special notes section)
API Standard 653 covers in service steel tanks built to what standards? -
correct answers - This standard covers steel storage tanks built to API 650
and its predecessor API 12C. (1.1.1)
What API Standard always governs for tanks that have been placed in
service? -
correct answers - In the case of apparent conflicts between the
requirements of this standard and API 650 or its predecessor API 12C, API
653 shall govern for tanks that have been placed in service. (1.1.2)
API Standard 653 employs the design principles of what standard? -
correct answers - This standard employs the principles of API 650. (1.1.3)
When design and construction details are not given and are not available
in the standard to which the in service tank was originally constructed,
then details that will provide a level of integrity equal to the level provided
by the current edition of which standard must be used? - correct
answers - The current edition of API 650 must be used. (1.1.5)
Who has the ultimate responsability for complying with the provisions of
API653?
- correct answers - The owner/operator. (1.2)
The inspector agency of the jurisdiction in which the above ground is
storage tank is operated is called what? - correct answers - Authorized
inspection agency (3.3)
An employee of an authorized inspection agency certified as an AST
inspector per API 653 Appendix D, is known as what? - correct answers -
Authorized inspector (3.4)
What is the total metal loss divided by the period of time over which
the metal loss occurred? - correct answers - Corrosion rate (3.9)
What is the definition of a "repair" to a tank? - correct answers - Work
necessary to maintain or restore a tank to a condition suitable for safe
operation. (3.24)
, What must be done when the results of a tank inspection show that a
change has occurred from the original physical condition of that tank?
- correct answers - An evaluation shall be made to determine its
suitability for continued use. (4.1.1)
What must be done when the cone roof tank roof plates corrode to an
average thickness of less than 0.09" in any 100 in^2 area? - correct
answers - Shall be repaired or replaced. (4.2.1.2)
What section of API 653 must be considered when changing the service of
a tank to operation at temperatures above 200F? - correct answers -
All requirements of API 650, Appendix M. (4.2.4.3)
What form of corrosion does not normally represent a significant threat to
the overall structural integrity of the tank shell unless it is present in a
severe and numerous form?
- correct answers - Pitting (4.3.1.3)
When can widley scattered pits inside the tank shell be ignored? - correct
answers - Provided that:
a) no pit depth results in the remaining shell thickness being less than
one-half the
minimum acceptable tank shell
thickness exclusive of the corrosion allowance; and
b)the sum of their dimensions along any vertical line does not exceed 2
in. in an 8-in. length (see Figure 4.2). (4.3.2.2).
A tank of a single butt-weld with a back-up bar construction, built to an
unknownstandard in 1940 is inspected. Corrosion is general and an
evaluation of the tank's minimum thickness is required. What joint factor
would you use? - correct
answers - E = 0.85. (Table 4.2)
What can foundation settlement cause to appear in the shell of an AST?-
correct answers - Shell distortions. (4.3.5.2, 4.3.5.3)
Unless a stress analysis is performed what is the minimum bottom plate
thickness in the critical zone of the tank bottom? - correct answers - the
smaller of one-half the original bottom plate thickness or 50 % of tmin of the
lower shell course, but not less than 0.1 in. (4.4.5.4)
An AST operating at 250F is evaluated for continuing service. The inspector
checks the tank records and finds that the tank was originally built of ASTM
A516 gr60. What allowable stress should the inspector use in evaluation the
minimum thicknesses of the tank's shell? - correct answers - 32,000 * 0.80
= 25,600 (4.3.10.1.1a or Table 4.1)
A six year old storage tank is inspected. The tank has a diameter of 125
feet and its maximum liquid level height is 40 feet. The tank was
constructed of ASTM A283 gr C
