API 653 Exam Chapter 6

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Take a Free API 653 Exam Chapter 6 Practice test with Latest Evaluation of Corroded Tanks Question and Answers

1.

Q1. API 653: isolated pitting
How many pits of less than half the minimum required wall thickness, each of 0.25 in diameter, are allowed in an 8 in vertical line of corrosion on a tank?

 
 
 
 

2.

Q2. API 653: joint efficiencies (unknown construction standard)
What is the weld joint efficiency factor for a tank built in 1950 with a single butt welded joint with a ‘back-up bar’? The construction standard is not known.

 
 
 
 

3.

Q3. API 653: allowable stress S
If the yield strength (Y) of a material of construction is 35 000 psi and the tensile strength (T) is 60 000 psi, what is the value of the maximum allowable stress for the bottom two courses of a tank made of this material?

 
 
 
 

4.

Q4. API 653: allowable stress for unspecified steel
What is the design strength of unspecified steel used in the top courses of a storage tank?

 
 
 
 

5.

Q5. API 653: calculation of the averaging length
The minimum shell thickness t2 (exclusive of isolated pits) in a tank of 100 ft diameter is measured at 0.375 in. What is the critical length over which the thickness readings should be averaged out?

 
 
 
 

6.

Q6. API 653: calculation of minimum acceptable shell thickness
A tank has the following dimensions:
Nominal tank diameter 150 ft
Total height of tank 30 ft
Maximum fill height 30 ft
Number of courses equally spaced 5
The specific gravity of contents 0.85
Construction code API 650 basic standard
5th edition
Material of construction A283 C
What is the minimum acceptable thickness tmin for the bottom
course? Use the ‘full course’ equation tmin = 2.6(H – 1)DG/SE

 
 
 
 

7.

Q7. API 653: hydro test height (entire course consideration)
An API 12C 15th edition tank of diameter 150 ft has a bottom course made of A285C. The measured minimum average thickness for the entire bottom course is 0.2 in. What is the maximum allowable fill height for hydro testing this tank?

 
 
 
 

8.

Q8. API 653: calculation of allowable t2 (including corrosion allowance)
A tank has an average minimum measured thickness (t1) of 0.5 in and has a design corrosion allowance of 0.125 in. What is the minimum allowable individual thickness (t2) of a corroded area anywhere, excluding any isolated pitting?

 
 
 
 

9.

Q9. API 653: bottom annular plate thickness
If the stress in the first course of a tank is 26 000 psi and the course is 1/2 in thick, what is the minimum thickness for the bottom annular plate?

 
 
 
 

10.

Q10. API 653: hydro test fill height for a complete tank
A tank is constructed to an unknown code but all the joints are butt welded. It is 120 ft in diameter and the material of construction is an unknown low carbon steel. There is localized corrosion on the bottom course and the minimum thickness is 0.25 in. What is the maximum fill height for hydro testing the complete tank?

 
 
 
 

11.

6.9 API 653 appendix B: tank bottom settlement: practice questions (set 2)

Q1. API 653: types of settlement
Shell settlement can be made up of three types. What are they?

 
 
 
 

12.

Q2. API 653: types of settlement
Which of these does not induce stresses in the tank structure (but may in the connections)?

 
 
 
 

13.

Q3. API 653: shell settlement
What shape does differential settlement follow?

 
 
 
 

14. Q4. API 653: maximum allowable deflection
Maximum allowable out-of-plane deflection S (ft) is given by the equation:
S< (L2 – Yx11) [2(ExH]
where
L = arc length (ft) between measurement points = 20 ft
Y = yield strength (psi) = 20 000 psi
E = Young’s modulus (psi) = 24×106 psi
H = tank height (ft) = 50 ft

What is the maximum allowable out-of-plane deflection S?

 
 
 
 

15.

Q5. API 653: shell settlement
In general, when is most settlement presumed to have occurred for (say) a 10-year-old tank that is showing settlement?

 
 
 
 

16.

Q6. API 653: edge settlement repairs
It is acceptable to repair the bottom-to-shell weld without further investigation by an experienced engineer as long as the actual settlement is not greater than:

 
 
 
 

17.

Q7. API 653: measured edge settlement
A tank which when new has the center of its bottom lower than its edges is called a:

 
 
 
 

18.

Q8. API 653: settlement
What are the ‘least squares fit’ method all about?

 
 
 
 

19.

Q9. API 653: settlement
What can be caused by rigid (planar) tilt?

 
 
 
 

20.

Q10. API 653: settlement
A lack of circularity at the top of a tank is typically a feature of:

 
 
 
 

Question 1 of 20

API 653 Exam Chapter 6 – Evaluation of Corroded Tanks Free Practice Test

Prepare for the API 653 Aboveground Storage Tank Inspector Exam with our free practice quiz on Chapter 6 – Evaluation of Corroded Tanks. This chapter is very important for candidates because corrosion evaluation is one of the key skills required for tank inspection, repair decisions, remaining life assessment, and fitness-for-service understanding.

If you are preparing for the API 653 exam, this free quiz will help you test your knowledge of corroded tank evaluation, minimum thickness requirements, corrosion rates, remaining life, inspection findings, and repair recommendations.

Take Free API 653 Chapter 6 Practice Test

Here you can attempt the latest API 653 practice questions and answers related to Evaluation of Corroded Tanks. These questions are designed to help you understand the exam pattern, improve your confidence, and revise important inspection concepts before the final exam.

This free practice test is useful for:

  • API 653 exam candidates
  • Tank inspectors
  • QA/QC inspectors
  • Welding inspectors
  • Mechanical engineers
  • Oil & gas inspection professionals
  • Storage tank maintenance teams
  • NDT and inspection personnel

What Is Covered in API 653 Chapter 6 – Evaluation of Corroded Tanks?

In this chapter, candidates learn how to evaluate corrosion damage in aboveground storage tanks. The main focus is to understand whether the tank can continue in service, requires repair, needs further inspection, or must be evaluated for reduced operating conditions.

Important topics include:

  • Evaluation of corroded tank shells
  • Minimum acceptable thickness
  • Corrosion rate calculation
  • Remaining life calculation
  • Localized corrosion and pitting
  • Bottom plate corrosion
  • Roof and shell corrosion concerns
  • Inspection data review
  • Repair or replacement decisions
  • Fitness-for-service thinking
  • Tank integrity and safe operation

Understanding these topics is important because API 653 inspectors must be able to review inspection results and identify whether corrosion affects the safety and reliability of the tank.

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Why Practice API 653 Chapter 6 Questions?

Many candidates read the code but still struggle during the exam because they do not practice enough questions. Practice questions help you understand how exam concepts are applied in real situations.

By taking this free API 653 Chapter 6 quiz, you can:

  • Improve your exam preparation
  • Understand corrosion evaluation concepts clearly
  • Practice calculation-based and theory-based questions
  • Identify weak areas before the exam
  • Learn important inspection terms
  • Build confidence for open-book and closed-book exam sections
  • Prepare with practical question-and-answer style learning

API 653 Corroded Tank Evaluation – Key Learning Points

Corrosion evaluation is not only about finding metal loss. An inspector must understand the location of corrosion, severity of damage, corrosion rate, required thickness, service condition, and inspection history.

A tank may have general corrosion, localized corrosion, bottom-side corrosion, roof corrosion, or shell plate thinning. Each condition must be evaluated properly before making a repair or continued-service decision.

This is why Chapter 6 is a very important part of API 653 exam preparation.

Start Your Free API 653 Practice Quiz

Click the quiz below and start your free API 653 Chapter 6 practice test. Read every question carefully, select the best answer, and review the explanation after each question.

These practice questions are prepared to help you study smarter and understand the important concepts of Evaluation of Corroded Tanks.

Who Should Use This Free API 653 Practice Test?

This free test is best for anyone preparing for the API 653 certification exam or working in the tank inspection field. It is also useful for professionals who want to improve their knowledge of storage tank inspection, corrosion evaluation, and repair requirements.

Whether you are a beginner or already experienced in tank inspection, this quiz can help you revise important points in a simple and practical way.

API 653 Exam Preparation Support

If you want to prepare seriously for the API 653 exam, regular practice is very important. Study the code, understand the concepts, and solve chapter-wise questions to improve your score.

Our free API 653 practice tests are designed to support your learning journey and help you prepare with confidence.

Start Learning Now

Take the API 653 Exam Chapter 6 – Evaluation of Corroded Tanks Free Practice Test and check your preparation level today.

Practice more. Learn better. Pass with confidence.

Click Here To Read Next API 653 Exam Chapter 7 –API 650: Tank Design

Now try these practice questions.

6.8 API 653 section 4: evaluation: practice questions (set 1)

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