API 653 Vol 1

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© Asian Training Academy. Pune, India 1

* STORAGE TANK INSPECTOR *

COURSE NOTES

VOLUME - 1

CONDUCTED FOR

Reliance Industries Limited

Navi Mumbai

CONDUCTED BY

Asian Training Academy, Pune.

19/ A-4 Sarita Vihar, S No 119/3/1 Parvati, Off Sinhgad Road, Pune 411030. India Tel: + 91-20-24252214, 24308068, E-mail: [email protected]

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API 653- STORAGE TANK INSPECTOR

PREPARATORY COURSE

CONDUCTED BY

Asian Training Academy, Pune.

Statement

This course manual has been prepared by Asian Training Academy, Pune; INDIA., strictly for the use of attendees to API-653 Examination Preparation Course from Reliance Industries Ltd. This manual is to be used as an aid to assist those persons wishing to take the API-653 Aboveground Storage Tank Inspector Certification Examination. This manual is not all-inclusive and should not be used in place of any recognized Code or Standard. The information contained in this manual was obtained from the author’s research and experience and is intellectual property of the author.

This manual or any part of it shall not be reproduced by any means without the written consent of

Asian Training Academy, Pune

.

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API 653- STORAGE TANK INSPECTOR PREPARATORY COURSE

VOLUME-1

1. Program Schedule

2. PART 1 - Examination/Certification Information from API.

3. PART II- Guidelines and useful tips for Examination

4. PART III- Case Studies- WPS/PQR Roadmap & Examples

5. PART IV- Mathematics in API 653 Exam.

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API 653- STORAGE TANK INSPECTOR PREPARATORY COURSE

PROGRAMME SCHEDULE

API 653 ABOVEGROUND STORAGE TANK INSPECTOR PREPARATORY COURSE DAILY TIME TABLE

Session I Session II Session III Session IV

Day 1 • Introduction • API 653: Examination Scheme • Question Types • API 650 Design Aspects API 650 – cont’d Design temperature Tank Materials Impact Testing of Materials

Weld sizes for shell and roof openings

API 650 – cont’d Shell design

Bottom & roof design Fabrication requirements • API 650 – cont’d • Inspection requirements • Extent of Radiography • Introduction to API 653 – Sec. 1 • Quiz (Day 1) Day 2 • Points to Recall-Day 1 • Review of Quiz-Day 1 • Introduction to API 653 • API 653 Sec. 4 • Existing tank shell

thickness evaluation • Evaluation of pitting

Evaluating of corrosion on bottom plates

Foundation evaluation API 653 – Sec. 5 Brittle

fracture API 653 – Sec. 6 Inspection frequency (routine inspection) External Inspection Internal Inspection Inspection Intervals Inspection Records API 653 – Sec. 7 API 653 – Sec. 8 API 653 – Sec. 9 Tank repair and

alteration Repair of Shell Quiz (Day 2) Day 3 Points to Recall Day2

Review Quiz -Day 2 Repair of Tank Bottom API 653 – Sec. 10 Dismantling and reconstruction API 653 – Sec 11 Welding API 653 – Sec. 12 Examination & Testing

API 653 – Sec. 13 API 653 – App. B Evaluation of Tank Bottom Settlement Reports & Records

API RP 575 Types of Tanks Procedures and

evaluations of internal and external inspection Quiz (Day 3)

Day 4

Points to Recall (Day 3) Review of Quiz

(Day 3)

Evaluation of change of service

Evaluation of flaws and distortions API RP 651 Cathodic Protection Requirement Methods of Cathodic Protection ASME Sec. V – NDT RT Examination Penetrant Testing, ASME Sec. V – NDT Magnetic Particle, UT Examination Quiz (Day 4) Day 5

Points to Recall (Day 4) Review of Quiz (Day 4) ASME Sec. IX

Welding Qualifications WPS/PQR

Review of WPS/PQR documents

Road map for document review

Case studies in WPS/PQR

API RP 652

Tank Bottom Lining Types of linings Selection and Application of Linings API 571 Damage Mechanisms Quiz (Day 5) Day 6

Points to Recall (Day 5) Review of Quiz (Day 5) API 571

Degradation mechanisms

API 577

Welding, NDT and metallurgy.

Final Simulated Test (Close Book) - Test Feedback

Final Simulated Test (Open Book) Test Feedback Concluding Session

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API 653- STORAGE TANK INSPECTOR

PREPARATORY COURSE

PART I

EXAMINATION/CERTIFICATION

INFORMATION

FROM API.

Asian Training Academy, Pune.

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API 653 CERTIFICATIN FOR IN-SERVICE INSPECTION

INTRODUCTION

1. Preamble:

Storage Tanks are the major installations in Petroleum Refineries, Petrochemical

plants, Oil terminals and other process plants. They store variety of fluids, which

may be Explosive, Corrosive or Toxic in nature. The equipments are also subjected to

fluid head pressures and moderate temperatures. All these factors may cause

corrosion and other damages to the vital equipments.

The corrosion may cause thinning, pitting or cracking of tank walls. The internal

head will tend to bulge the tanks or piping at the corroded locations, releasing the

explosive or toxic contents resulting in serious consequences to the plant, personnel

and the people at large. It is therefore essential that during the planned shutdowns,

the degradation and damages inflicted to the Plant equipment, Piping and Tanks

should be monitored and evaluated so as to arrive at the ‘3R’ decisions. i.e.’

Run-Repair-Replace” decisions.

More specifically, these courses describe the essentials of what to inspect, where to

inspect, how much to inspect and what to accept so as to evaluate the safety and

mechanical integrity of in-service equipments. The courses also cover methods of

repair, alteration, re-rating and replacements of affected equipments.

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2. Course objectives:

The API Courses provide the participants the guidelines and methodology of

carrying out inspection of “in-service” equipments. It also provides techniques for

the assessment of the wear and tear of the equipments as well as to measure

de-gradation and damages caused to the process equipments due to the process

conditions.

If the assessment indicates that the equipment is safe to run, the participants are

further taught how to estimate the safe remaining life and the methods to extend the

useful life of the equipments.

If the decision is that the equipment needs repair, the course teaches the

participants, how to carry out such repairs of the damaged part without causing

damage to the whole equipment. It also covers the methods of re-rating the

equipment by evaluating the mechanical integrity if it is not possible to restore the

equipment to its original design conditions.

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PUBLICATIONS EFFECTIVITY SHEET

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Examination Information

1. API 653 examination consists of 150 multiple-choice questions with an open and closed book sections. The examination is administered by participating members of the National Board of Boiler and Pressure Vessel Inspectors and by the Professional Examination Service (PES). Total length of examination is 8 hours. Individual jurisdictions may charge a sitting fee to take the examination in their jurisdiction. Please contact the jurisdiction you select for an exact amount. There is no additional sitting fee at the locations where examination is administered by PES.

2. If you pass the examination, and all sections of your application are complete, you will be certified and receive a wallet card and a certificate approximately 3 months after the examination date.

3. API grants each applicant three consecutive attempts during the 18-month period to sit and pass the test, starting with the first exam administration the applicant registers for. If you fail the examination on your first attempt, you may retake it twice. If you fail to appear for the test, it will still count as an official attempt.

4. If you do not pass the examination on the first attempt, you need to submit a $50.00 rescheduling fee. If you do not pass it on the second attempt, you must also submit an updated Employment Reference form. If the candidate is unsuccessful on the third attempt, a new application must be submitted with a new application fee.

5. Examination results will be mailed to you approximately 8 weeks after you have taken the exam. DO NOT call API, PES, or your jurisdiction for examination results; these results WILL NOT be given over the telephone.

What to Bring to the Examination o No. 2 pencils;

o A non-programmable calculator (a calculator with only simple functions); o The applicable API and ASME reference publications. Please note: highlighting,

underlining, page tabs, and notes written in margins of the code books are acceptable. However, loose pages inserted in the code books are not acceptable. Note: API and ASME publications are copyrighted material. Photocopies of publications are not permitted at the exam;

o Your examination site confirmation letter; o A picture ID (i.e. driver’s license).

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Step-by-step certification process

Please complete the following steps in order to get certified:

1. Check out minimum qualification requirements for your chosen certification

program, and confirm your eligibility for certification.

2. Review API's testing and certification policies.

3. Determine the most convenient location, test date and application deadline for

your chosen program.

4. Download the application for your program or request the application package

to be sent to you via mail.

5. Fill out your application completely.

6. Mail your application, supporting documentation and payment to API by the

deadline indicated.

7. Download the Body of Knowledge for your chosen program.

8. Obtain necessary technical documents and publications. Effective publication

dates are listed in the application package.

9. Prepare for examination. Training programs are optional and not provided by

API.

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EXAM DATES AND APPLICATION DEADLINE CHART

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Test Development and Grading

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API 653- STORAGE TANK INSPECTOR

PREPARATORY COURSE

PART II

GUIDELINES AND USEFUL TIPS FOR

API 653 CERTIFICATION

EXAMINATION

Asian Training Academy, Pune.

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Preface

This examination preparation course is designed to prepare the participant to

successfully sit for the API-653 exam. Through your concentrated effort, and

the material provided in this course, you should have sufficient information to

pass the examination.

The majority of the classroom study will focus on the “Open Book” portion of

the exam. The goal, since this is open book, is to obtain a perfect score in this

section. Study for the practical questions (Closed Book) will be included in the

daily classroom activity and assigned homework.

The material contained in this manual is to be thoroughly studied and practiced

prior to attending the course. The math examples and practice problems are

based on the types of questions given on the API-653 exam. Through the use of

these examples, you will be exposed to many of the formulas used during the

course.

Remember, this is a very intense course. There will be eight hours of classroom

study each day. The instructor will be available to answer questions or to assist

any participant having difficulty with the homework assignments or any topic

discussed during class. There will be from two to three hours of homework

assignments each day. Daily quizzes are given and one practice API-653

examination is provided. The pace is fast and focused.

The participant is responsible for making all arrangements for taking the

examination including confirming your eligibility and applying to the American

Petroleum Institute.

No reference material of any kind will be permitted during the closed book

portion; some examining proctors may permit language translation dictionaries.

There will be some common knowledge mathematical questions on the

practical portion of the exam - remember to have your calculator available for

this part of the exam.

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During this course, we will attempt to duplicate actual examination conditions

including using a separate answer sheet during the practice examination.

1. EXAMINATION SCHEME

As per the present scheme, API 653 examination is one-day, 8-hour, 2

session examination, comprising of pre-lunch session (4 hours) for

“open-book” examination and post-lunch session (4 hours) for

“closed-book” examination.

There are a total of 150 questions carrying 1 mark each (total of 150

marks), split into open-book (approximately 50 questions) and

closed-book (approximately 100 questions). The distribution of 50 and 100

questions respectively for open-book and closed-book examinations is

approximate; however the total is always 150 questions.

Each question is multiple choice questions with given 4 possible choices.

Only one is the correct choice. The candidate has to pick-up the correct

choice and indicate the same on separate answer sheet. The answer sheet

along with the question paper should be returned back to the Supervisor.

The correct answer is to be indicated by blackening (filling) the relevant

circle by a pencil. There is no set passing percentage. However a score of

about 95 to 105 out of 150 is a good estimate of passing score.

Please note the following:

• Fill only one circle out of four given

• Fill the circle fully and completely. Half or less than half

blackened circle area is not reckoned for answer.

• Never indicate the answers by ticking (√) the circles.

• There is no negative marking.

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and other documents as per “Effectivity Sheets”. Code pages may be

tabbed, highlightened, underlined or notes in margin of the pages are

accepted. Additional new pages to codes are not accepted. Always carry

the following to the exam hall.

• 2 Nos. B or 2B pencils and eraser

• Non-programmable calculator

• Photo identity (passport, driving license, etc.)

• Exam confirmation letter

Be present in the exam hall at least 15 minutes prior to scheduled start of

exam. The supervisor announces important instructions during this

period. Do not miss them. Now relax and attempt the exam calmly. Time

is always more than enough.

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2. DISTRIBUTION

OF

MARKS

As per the Effectivity Sheet, there are total 9 codes prescribed for examination.

However, all of them are not equally important and do not therefore require

equal emphasis. About 50 percent questions are asked from one code API 653

which is hardly 40 pages, while all other 8 codes contribute 50% marks which

are more than 1,000 pages. Following distribution scheme will help the

participant to decide how much time he should spend for each document during

preparation.

3. Codes and Standards for study and their weight age:

Note: The weight age indicated is approximate and for guidance only.

A . API Publications:

API RP 650 Vertical storage tanks Construction code

20 %

API 653, Aboveground tanks Inspection Code

45 %

API RP 575, Inspection of Storage tanks

06 %

API RP 651 Cathodic Protection of Storage tanks

05 %

API RP 562 Lining of Tank bottom

03 %

API RP 571, Damage Mechanisms

03 %

API RP 577, Welding Inspection and Metallurgy

03 %

B. ASME Publications:

Section

V,

Nondestructive

Examination 07

%

Section IX, Welding and Brazing Qualifications

08 %

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As stated earlier, the examination comprises of open book and closed book

parts. The closed-book examination includes such questions which the inspector

is normally expected to know without referring the Codes, i.e., the questions are

“awareness level” questions.

Whenever you find a very definitive or quantitative statement in body of the

Code, a closed book question may be expected on it. Thus, the basic

requirements of a code, specific “DO” and “DON’T” statements, important

quantified statements, important definitions and well-known inspection

principles will constitute such questions.

Where the student is required to refer to the diagrams or formulas or tables or

graphs and curves from the Codes, it will always be an “open-book” question.

All calculation oriented questions will normally be “open-book” type. The Code

information which is not short and crisp, (i.e., large paragraphs, several

descriptive statements clubbed together) will normally be asked in “open-book”

part. Here the participant is expected not to remember the information but

should know where to find it in the body of the Code.

The questions asked in closed book part are straight forward statements directly

taken form Code without much of the modifications and therefore are easy to

answer. To answer open-book questions, one only needs to know where to find

the answer in the code and therefore tabbing of Code pages, highlighting the

paragraphs or additional explanatory notes in page margins is useful for saving

time. Closed-book part of the exam (100 marks) can be finished in hardly 2 to 2

½ hour though 4 hours are allotted. While “open-book” part (50 marks) takes a

little longer and may require all the 4 hours that are allotted.

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4. HOW TO PREPARE FOR EXAM:

If your aim is only to get “certified”, i.e., to obtain just around 100-110 marks,

detailed study of documents nos. 1 to 4 above (Chapter 2) may be adequate.

Additionally, one should try to remember all the “Points to Recall” and review

the mock examinations attempted during the Preparatory Course. If two or more

participants from same organization are appearing for exam, then joint

discussions and one putting question to another and vice versa has been found

very effective during preparation. Other 5 codes (i.e., Serial No. 5 to 9) may be

studied in detail if there is additional preparation time available. An overall

“awareness” level knowledge of these 5 Codes may be okay.

If your objective is to get certified and also to obtain a good score, (say 125+)

then it is worthwhile to study the 5 Codes (Serial No. 5 to 9). However, please

remember that study of API 653 has to be “thorough” and total, while study of

API 650, ASME Sec. IX and ASME Sec. V should be such that it can cover the

topics mentioned in the “Body of Knowledge”. The last 5 Codes (Serial No. 5

to 9) should be read at least once and note the important points. A very

“thorough” study of these documents however will not result in “gains”

commensurate with the efforts put in.

If you are about a month away from examination, read all the Codes at least

once and concentrate on highlighted text in the Codes and also try to solve the

question bank.

If you are about two weeks away from the exam, concentrate on highlighted

text as well as the mock examinations conducted during the course. In the last

week of preparation, focus on Points to Recall and mock exams.

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5. TIPS FOR MAXIMIZING THE SCORE

a.

There are only 5 or 6 important definitions from Chapter 3 of API

653. Normally 3 to 4 definitions are asked in closed-book exam.

b.

From Chapter 4 of API 653, nearly 15 questions are asked (7 to 8

closed book and 7 to 8 open book). Concentrate more on clauses

4.2.1.2, 4.2.3.1, 4.2.4.3 to 4.3.7.

c.

Chapter 5, knowing figure 5-2 and only 3 clauses 5.3.5 to 5.3.7 is

enough.

d.

From Chapter 6, about 10 questions are asked. It is only 3 page

chapter. Particularly pay attention to Inspection intervals.

e.

From Chapter 7 and Chapter 8, generally 2 or 3 questions are

asked.

f.

Chapter 9, about 7 to 8 questions are asked. Concentrate more on

Figure 9-1 and hot tap (Clause 9.14).

g.

Chapter 10, about 3 or 4 questions are asked and those generally

“open book” type. So you can refer to the code and get answers.

h.

Chapter 11, it is hardly 8 to 10 lines chapter but 1 or 2 questions are

asked

i.

.Chapter 12, about 7 to 8 questions are asked. Normally the

questions are on NDT. The participant is expected to know that

NDT procedures shall be as per relevant article of ASME Sec. V,

the NDT extent shall be as per API 650 or 653 while acceptance

criteria is as per API 650 or ASME Sec. VIII, Div. 1. he should

also know that qualification standard of NDT personnel is ASNT

SNT-TC 1A (or API 650). This chapter is better explained in

Appendix F (API 653) as NDE Summary or in Appt. (API 650)

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j.

Chapter 13, generally 1 question covering name plate stamping is

asked.

k.

Appendices: App. A. Here note that API 650 was introduced in

1961 (prior to this was API 12C) and seventh edition (1980)

onwards the joint efficiency (E) is taken as 1.

App. B: The important topics are number of settlement monitoring points

(Figure B-1, B-2) and formula B = 0.37 R (R in feet while B is in

inches)

App. C: This being item wise inspection checklist concerning what to check

where. Normally, 1 or 2 open book questions are set. No need to

remember this table.

App. D: Note certification requirement (Clauses D.2 and D.5)

From API 650.

Normally, two questions are asked on materials. (Fig. 2-1, Table 2-3, Table 2-4

and Clause 2.8).

Usually 5 to 6 questions are asked on Chapter 3 concerning shell, bottom and

roof thickness, attachment welds.

From Chapter 5, normally 2 or 3 questions will be asked. Focus on weld

reinforcement, undercuts, use of low-H electrodes and inspection pressure for

pad-test and vacuum box test.

From Chapter 6, generally 3 questions covering number of radiographs (Fig.

6-1) and acceptance standards and personnel qualifications are asked.

Since there is no negative marking, there is no harm in making guess.

Generally, do not go against your first impulse, unless you are sure you were

wrong in the first place. If some questions are still remaining unanswered

mark the answers you “feel” may be right. Do not leave any question

unanswered.

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Both “open” and “closed” book sessions are 4 hours each. This means about

25 to 28 questions per hour for closed book and 12 to 15 questions per hour

for open book. For proper time management following are useful

suggestions.

a) You may start from Question No. 1 and proceed. If after 1 hour you

feel that you are maintaining the required progress as mentioned

above proceed serially.

b) If, however, you are behind the required rate, start jumping the

questions, i.e., start attempting those questions you can answer,

deleting whose answer you do not know. Proceed like this till the end.

Do not leave any question unanswered whose answer you know.

c) Then come back to “deleted” questions and attempt them using your

“feel” factor. Go on like this till say last 10-15 minutes are remaining.

d) If there are still some questions where you have no clue at all just

mark the answer at random in last 10-15 minutes. This may give you

few chance marks. Do not leave any question unattempted.

After completion of writing exam, if you have still time (which you normally

have) you may go through your answers just to check quickly if you have filled

a wrong circle.

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TEST TAKING TIPS

● Don’t read too much into a question. Do not get too

elaborate and ruin your answer.

● If two choices are very similar, the answer is probably not

either of them.

● If two choices are opposite, one of then is probably

correct.

● Don’t go against your first impulse unless you are very

sure you were wrong.

● Check for negatives and other words that can throw you

off.

● The answer is usually wrong if it contains “all,” “always,”

“never,” or “none.”

● The answer has a great chance of being right if it has

“sometimes,” “probably,” or “some.”

● When you don’t know the answer, look for the wrong ones.

● If you are supposed to read a long passage and then answer

questions about it, read the question first. That will tell you

what you are looking for and affect the way you read the

passage.

● Be suspicious of choices that seem obvious.

● Don’t give up on a question that, after one reading,

seems complicated. Looking at it from a different angle,

restating it in your own words, drawing a picture, or

breaking it down, etc., may help you realize that it’s not as

hard as you thought.

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IMPORTANT CLOSED BOOK QUESTIONS

No. QUESTION CODE

CLAUSE

1 Definition of the Critical zone

API653 3.7

2 Definition of Change of Service

API653

3.9

3. Minimum thickness of corroded roof plate

API653

4.2.1.2

4. Limits of L

API653

4.3.2.1

5. Definition of widely scattered pits

API653

4.3.2.2

6. Causes for shell distortion

API653

4.3.5.2

7. Cracks in the shall to bottom weld – what should be done

API653

4.3.6

8. What is the reason for the distortion of anchor bolts &

excessive cracking of concrete structures

API653 4.5.3

9. Tanks fabricated from steels of unknown toughness,

thickness less than ½” can be operated at above what

minimum shell metal temperature

API653 5.3.7

10. Interval for routine In-service inspection

API653

6.3.1.2

11. Who shall carry out External Inspection

API653

6.3.2.1

12. Interval for External inspection

API653

6.3.2.1

13. How is the external inspection of Insulated tank carried

out

API653 6.3.2.2

14. What is the method of external inspection of Tank

grounding system

API653 6.3.2.3

15. Interval for ultrasonic thickness inspection

API653

6.3.3

16. If internal inspection is solely for the purpose of

determining the condition & integrity of tank bottom what

is the method of inspection

API653 6.4.1.2

17. alternative Internal Inspection method

API653

6.4.3

18. What is the bottom plate minimum thickness

API653

Table

6-1

19. Construction records shall include the following

information

API653 6.8.2

20. New material for tank reconstruction shall comply to which

standard

API653 7.2

21. Welding consumables shall conform to which specification

API653

7.4

22. What are the minimum dimensions for a replacement shell

API653

9.2.2.1

23. The corners of a repair plate shall be rounded to what

minimum radius

API653 9.3.1.4

24. Insert plate having higher thickness than the shall plate shall

be tapered to

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API 653 Preparatory Course

IMPORTANT CLOSED BOOK QUESTIONS

(Cont…)

No. QUESTION CODE

CLAUSE

25. Minimum thk. of new roof to be used for repair for a fixed

roof shall be

API653 9.11.1.1

26. The minimum height of tank liquid above hot tap location

shall be at least

API653 9.14.1.2

27 During hot tapping operation welding will be done using

which electrodes

API653 9.14.2.3

28. Are hot taps permitted on the roof of a tank

API653

9.14.2.4

29. The maximum allowed undercutting for horizontal joints of

a reconstructed tank is

API653 10.4.2.5

30. If the material specification for the steel from an existing

tank is unknown or obsolete, how do you qualify the

welding procedure

API653 11.1.2

31. At what intervals Welders identification shall be marked

adj. to welds

API653 11.2.2

32. What alternative methods are used to inspect the integrity

of the welded bottom joint

API653 12.1.7.1

33. Areas of bottom plate repaired by welding in addition to

MT/PT are any other testing done.

API653 12.1.7.3

34. The minimum diagnostic length of each radiograph is

API653

12.2.1.7

35. For penetration installed using insert plates , butt weld

between the insert plate & shell plate shall be radiographed

to what extent

API653 12.2.1.8

36. Hydrostatic test of a reconstructed tank shall be held for

how long time.

API653 12.3.1.1

37. At what intervals shall settlement be measured during

hydrotest

API653 12.5.2

38. The maximum spacing across diameter over which

measurements of bottom settlement are taken is

API653 Fig.

B-2

39. Internal Bottom settlement formula

API653

B-3-3

40. What is the NDT Inspector Qualification requirement for

carrying out UT during tank repair?

API653 F

4.3

41 UT procedure shall follow which Code/Standard

API653

F 4.4

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API 653 PREPARATORY

IMPORTANT OPEN BOOK QUESTIONS

No. QUESTION CODE

CLAUSE

1 Calculate the t min. welded tank shell

API653

4.3.3.1

2 What is the maximum allowable stress for bottom & second

course

API653 4.3.3.1

3. To change the service of the tank to above 200°F what

requirements are to be met

API653 4.2.4.4

4. What is the maximum allowable stress for reconstructed

tank

API653 4.3.3.1

5. What is the maximum allowable stress for revited tank

API653

4.3.4.1

6. Annular bottom plate thickness (Sp. Gr. < 1.0)

API653

Table 4-4

7. Assessment of the safe use of a tank constructed of

unknown materials

API653 Fig.

5.2

8. What records shall be maintained by the Owner / Operator

API653

6.8.1

9. What are the material specifications for structural materials

API653

7.3.2

10. Shell design for a reconstructed tank, with materials whose

allowable stresses are not given in Table 3-2 of API 650,

what allowable stresses are to be taken

API653 8.4.2

11. After the valve has been installed on the flange at what

pressure the pressure test shall be performed

API653 9.14.5.3

12. In tank re-construction, new vertical joints in adjacent shell

courses shall be offset by what minimum distance

API653 10.4.2.1

13. During tank reconstruction / repair what is the maximum

allowed undercutting for vertical joints

API653 10.4.2.5

14. What is the maximum reinforcement allowed for horizontal

joint of ¾” plate

API653 Table

10-1

15. In completed horizontal butt joints, the upper plate shall not

project beyond the lower plate by how much

API653 10.4.4.2

16. Calculation of Internal Bottom settlement or bulges

API653

B.3.3

17. Problem on edge settlement

API653

Fig B-10

18. For welding A516 Gr 70 materials what electrode

(50)

API 653- STORAGE TANK INSPECTOR

PREPARATORY COURSE

PART III

CASE STUDIES

Asian Training Academy, Pune.

(51)

(Question)

An Aboveground Storage Tank is to be constructed using ASTM A 516 gr 60

plates. The plates are normalized. The plates were tested for impact value and

the following were the test results. The test results are presented for 32 mm thk

plates (Lot A) and 30 mm thk plates (Lot B).

A) Longitudinal Specimen:

Three specimens failed at 13 ft-lb, 15 ft-lb and 18 ft-lb respectively

B) Transverse Specimen:

Three specimens failed at 12 ft-lb, 14ft-lb and 14ft-lb respectively

Your assessment is:

a.

Plate A is okay. B is not.

b.

Plate B is okay. A is not.

c.

Both A and B are okay.

d.

Both A and B are not okay.

(52)

A P I 6 5 3 T R A I N I N G C O U R S E

Case Study 1: Impact Testing of Plates

(Solution)

The material belongs to Group III A.

The thicknesses are within acceptable limits.

(Ref: 2.2.2, 516 gr60 can be used up to 40 mm thickness)

Plate A (Longitudinal):

Average of 3 specimen =

3

16

15

13 +

+

_{= 14.66 ft. lb.}

Average of 3 specimen, 14.66 ft. lb is less than required average of 15 ft. lb. —

Reject.

Plate B (Transverse):

Average of 3 specimen =

3

14

12 +

+

_{= 13.33}

Average of 3 specimen, 13.33 is greater than required average of 13 ft. lb.

Also only one specimen (12 ft. lb) is below average and its value is greater than

2/3 x 13, i.e., greater than 8.66.

Accept Plate B.

Correct answer: b

(53)

(Question)

The following data are presented for an Aboveground Storage Tank:

1)

Code of construction: API 650

2)

Tank diameter = 60ft

3)

Tank height = 48ft; width of plates used = 8ft

4)

Maximum fill height = 48ft

5)

Product specific gravity = 0.92

6)

Material of construction; ASTM A 516 gr 60

7)

Corrosion allowance = 1/8 in

Determine:

a. Required thickness for bottom course (first course)

b. Required thicknesses for courses 2 to 6

(54)

A P I 6 5 3 T R A I N I N G C O U R S E

Case Study 2: Shell Design of AST (New Tank)

(Solution)

a.

(

)

_CA

S

G

H

D

t

d d

+

−

=

2 .

6

1 or

(

)

t t

S

H

D

t

=

2 .

6 −

1 From table 3.2,

S

_d

=

21 ,

300 psi

,

S

_t

=

24 ,

000 psi

(

)

_in

t

_d

8

1 21300

92 .

0

1

48

60

6 .

2 ×

×

−

×

₊

=

∴

"

4417

.

0

125 .

0 3167

.

0 +

=

∴

t

_d

(

)

"

3055

.

0 24000

1

48

60

6 .

2 =

−

×

=

t

" 3055 . 0 " 4417 . 0 >

Select 0.4417” thick plate, i.e. 11.22 mm

Use 12 mm thick plate

b.

It is obvious that for all other courses, t

d

will govern, since t

d

will be

greater than t

t

(

)

_CA

S

G

H

D

t

d d

+

−

=

2 .

6

1 • For the 2

nd

_{Course, H = 40ft}

(

)

in

t

_d

8

1 21300

92 .

0

1

40

60

6 .

2 +

×

−

×

=

∴

(55)

• For the 3

rd

_{Course, H = 32ft}

(

)

in

t

_d

8

1 21300

92 .

0

1

32

60

6 .

2 +

×

−

×

=

∴

mm

t

_d

=

0 .

2089

+

0 .

125 =

0 .

3339

"

=

8 .

48 ∴

_{Use 10mm plate}

• For the 4

th

_{Course, H = 24ft}

(

)

in

t

_d

8

1 21300

92 .

0

1

24

60

6 .

2 ×

×

−

×

₊

=

∴

mm

t

_d

=

0 .

1550

+

0 .

125 =

0 .

2800

"

=

7 .

11 ∴

Use 8mm plate

• For the 5

th

_{Course H = 16ft}

(

)

_in

t

_d

8

1 21300

92 .

0

1

16

60

6 .

2 ×

×

−

×

₊

=

∴

mm

t

_d

=

0 .

1011

+

0 .

125 =

0 .

2261

"

=

5 .

74 ∴

Use 6mm plate

• For the 6

th

_{Course H = 8ft}

(

)

_in

t

_d

8

1 21300

92 .

0

1

8

60

6 .

2 ×

×

−

×

₊

=

∴

mm

t

_d

=

0 .

0472

+

0 .

125 =

0 .

1722

"

=

4 .

37 ∴

5mm plate may be OK

But, As per table 3.6.1, (Diameter-Thickness Table) minimum thickness

(for D = 60ft) is 6mm. Use 6mm plate

(56)

A P I 6 5 3 T R A I N I N G C O U R S E

Case Study 3: Tank Shell Thickness Evaluation (Old Tank)

(Question)

Data: Code of Constr. API 650 – Basic. Year of Constr. 1984

1)

Tank diameter = 100 feet

2)

Tank height = Maximum liquid height = 56 feet

3)

Course width = 8 feet

4)

Product specific gravity = 0.98

5)

Corrosion rate = 0.1 mm / year

6)

Thickness provided = 20mm (new)

7)

M. O. C. = ASTM-A-36

8)

After 20 years, a patch was observed on the second shell course, at

46 feet from the top (i.e. in 2nd course). Least thickness in the area

of corrosion was 15.25mm (0.6”). The next interval for inspection

is 10 years.

9)

Readings in vertical planes a, b, c, d over the length L were:

No. a b c d 1 19 18.5 18 18.5 2 18 18 17.75 17.5 3 18 17.5 15.25 17.5 4 17 18 16.5 18 5 19 18.5 17.5 18.5

(57)

(Solution)

1)

t₂ =0.6"=15.25

2)

L=3.7 D×t₂ =3.7 100×0.6 =28.66"

3) t

avg

for plane a = 91/5 = 18.2 mm. (Total of 5 readings = 91)

t

avg

for plane b = 90.5/5 = 18.1 mm (Total of 5 readings = 90.5)

t

avg

for plane c = 85/5 = 17.0 mm (Total of 5 readings = 85)

t

avg

for plane d = 90/5 = 18.0 mm (Total of 5 readings = 90)

So, the weakest plane is c. And lowest of t

avg

= 17 mm

mm t₁ =17 ∴

4)

mm

SE

G

H

D

t

0 .

471 "

11 .

965 24900

98 .

0

46

100

6 .

2

6 .

2

min

=

×

=

×

=

For safe operation:

(

CR Interval

)

t

t₁ ≥ _min + ×

and

t₂ ≥0.6×t_min +(CR x interval) 10 1 . 0 965 . 11 17≥ + × 15.25≥0.6×11.965+1 965 . 12 17≥

OK

15.25≥8.179

OK

Therefore the tank is safe.

(58)

A P I 6 5 3 T R A I N I N G C O U R S E

Case Study 4: Minimum Thickness of Bottom Tank Evaluation

(Question)

An aboveground storage tank provided with sketch plate type bottom

construction was observed to be having following thickness readings on bottom

plate by UT measurement. (The tank does not have leak detection system on

bottom.)

Bottom thickness provided when tank was new (excluding corrosion allowance

= 10 mm. Maximum depth of corrosion pits from inside of tank on the tank

bottom = 3.5 mm. Maximum corrosion from bottom side (metal loss) = 4.5 mm.

Rate of corrosion on topside of bottom = 100 microns / year. Rate of corrosion

on bottom side = 150 microns / year.

(59)

(Solution)

RT

bc

=

10 – 4.5 = 5.5 mm

RT

ip

=

10 – 3.5 = 6.5 mm

M RT =

0.1” (from Table 6-1) = 2.5 mm

M RT =

(Minimum of RT

bc

or RT

ip

) – O

r

(S

t

P

t

+ U P

r

)

2.5 =

5.5 - O

r

(0.1 + 0.15)

O

r

x 0.25 = 3.0

O

r =

3.0 / 0.25 = 12 years

Answer: 12

years

Note: In examination, problems will be simple. Out of the various terms in

formula for MRT, all data except one will be given and you will be asked to

find the missing one.

(60)

metal

Is unit stress > 95% of SMTS of base metal

If the welder is to be qualified on the basis of PQR. Is his Identifying code.

Position of welding recorded on

Start

Is the WPS supported by PQR. Does WPS show

reference No. of the supporting PQR

Has PQR been revised

Is PQR signed and

Accept for detailed review Ye Ye

R

E

J

E

C

T

Start at Front side of PQR.

For tensile test are qty of specimen, area and unit stress

calculation right

Is location of failure stated

Place WPS & PQR side by

Ye No

Is bend test Qty, type stated and correct Was break in weld No No No No No Ye Ye No No Ye

Are results for toughness test (if

any) OK

No Yes Go to tables as follows SMAW - QW 253 SAW – QW 254 Check WPS/PQR for QW 402

to QW 410 for the following WPS: EV, NEV, PQR: EV, Do the P, F & A Nos. match with mtl. Spec No & filler AWS

Ye Ye Ye No (QW – (QW – 153) (QW – 153) (QW – No

Go to back side of PQR.Are the results for tensile, and bend tests stated.

No Ye Accept No (QW 140) (QW – 163) (QW – 172) Yes Ye No

(61)

(Refer to Attached PQR / WPS Documents)

Note: Encircle the letter of only one alternative which you think is most appropriate.

1. Choose correct statement from the following:

a.

The PQR shows root spacing of 1/8” and same shall be followed in

production welding.

b.

PQR shows beval angle 37°. It shall be followed in production

welding without change.

c.

PQR does not show backing ring, hence production weld also can

not be with backing ring

d.

None of above is correct statement.

2. What condition below describes the results of the guided bend test?

a.

The three bend tests are acceptable and the fourth one is not

acceptable

b.

The test result overall is acceptable

c.

The test result is not acceptable due to the linear indication

d.

The bend test result is indeterminable, carry out retest.

3. What welding process is qualified by this PQR?

a.

GTAW

b.

SMAW

c.

GMAW

d.

SAW

4. What is the P number and the tensile strength of SA-106-C?

a.

P No. 1 and 70 ksi

b.

P No. 1 and 60 ksi

c.

P No. 3 and 70 ksi

d.

P No. 3 and 60 ksi

(62)

5..

In accordance with the PQR, the WPS is qualified for what welding

positions?

a.

Flat and horizontal

b.

Flat, vertical, overhead and horizontal

c.

Vertical and overhead

d.

All positions

6. What is the F No. of an E 7010 electrode?

a.

F no. 4

b.

F No. 3

c.

F No. 2

d.

F No. 1

7. The welder who welded the test plate for PQR 101 is qualified to weld in

what position?

a.

Flat

b.

Flat and horizontal

c.

Flat and vertical

d.

Flat, vertical and horizontal

8. The bend test specimen used are side bend. They are:

a.

Not accepted since 2 face bend and 2 root bend must be used

b.

Accepted since as alternative to (a) 4 side bend may be used

c.

Accepted since only 2 bend tests are required where as 4 bend tests are

performed

d.

Not accepted since all 3 types of bend tests (face, root, side) are

required.

9. As far as thickness ranges for Base Metal (B.M.) and weld metal (W.M.)

as shown on WPS are concerned, your decision about the qualified range

is:

a.

B.M. is okay and W.M. is not okay.

b.

Both B.M. and W.M. are okay.

c.

Both B.M. and W.M. are not okay.

d.

W.M. is okay and B.M. is not okay.

(63)

PREPARATORY COURSE

PART IV

CALCULATIONS IN

API 653 EXAMINATION

Asian Training Academy, Pune.

(64)

Calculation questions found on the API-653 examination are oriented toward existing tanks and not new tanks. API authorized above ground storage tank inspectors are expected to be able to check and perform calculations necessary to ensure compliance with appropriate Codes and standards. For this reason, the inspector must have a thorough understanding of the formulas and procedures used to calculate the following:

Corrosion Rates and Inspection Intervals Remaining Life determination

Joint Efficiencies

Maximum Height (Hydrostatic Testing)

Determining appropriate weld sizes for shell opening Minimum spacing between existing and new hot tap nozzles Settlement evaluation including the number of survey points

Minimum Thickness for Existing Tank and Reconstructed Tank Shells Corroded areas of tank shells including evaluation of pitting

Bottom plate thickness determination and evaluation Reinforcement of opening

The American Petroleum Institute does not permit the use of programmable calculators while taking the exam; therefore, programmable calculators will not be permitted during the course.

Mathematics Fundamentals:

As we all know, mathematics has a language of its own, made up of signs, symbols, and characters. During this course of study many common mathematical signs, symbols, and characters, which you must be familiar with, will be used. Some of these are listed below.

+ Addition − Subtraction ∗

×

( ) Multiplication

÷

Division π Pi Expressed as 3.14 < Less than > Greater than ∴ Therefore

≤ Less than or equal to ≥ Greater than or equal to

= Equal

X2_Number_squared

(65)

© Asian Training Academy. Pune, India 65 1. Find the minimum acceptable shell plate thickness of the first course of an AST.

tmin = Minimum acceptable thickness ?

D = Nominal diameter of tank, in feet 120 H = Height of tank in feet 48 G = Specific gravity of contents 1

S = Maximum allowable stress 21000 E = Joint efficiency of tank .85

t

D H

G

SE

min

.

(

)

=

2 6

−

1

2. Find the corrosion rate of an AST given the following information. Original thickness = .875”

Measured thickness = .625

Years since last thickness measurement = 11

CR

t

Time

original last

=

−

3. Using the corrosion rate determined in problem number 2, what would the remaining life expectancy of this tank be if the minimum required thickness is 0.436”?

RL

t

CR

actual imum

=

−

min

4. Shell settlement evaluation measurements are to be taken on a 146 feet diameter AST. Given the following formula, how many elevation measurements would be required?

N

=

D

10

5. Using the information in number four, does this number meet the requirements of API-653, which does not permit the measurement points to exceed 32 feet?

Dis

ce

D

N

(66)

6. Find the throat of a right angle fillet weld with a weld leg length of .4375 inches.

7. Using the following information, what is the maximum vertical length (also known as critical length), in inches, over which hoop stresses are assumed to “average out” around local discontinuities? Diameter of the tank is 136 feet, the least thickness in an area of corrosion, exclusive of pits, is determined to be .563”

L= 3 7. Dt₂

8. A 6 inch nozzle is to be placed in the tank shell of an AST. The shell course where the nozzle will be installed is .875” thick. What is the required area of reinforcement?

A OD

=

_{nozzle shell}

t

9. The maximum ultrasonic thickness measurement interval shall be five years when the corrosion rate is not known. What is the interval based on a known corrosion rate? The tank information is as follows: Initial thickness of the tank was 1.0625”, the actual thickness is .815”, the calculated required thickness is .473”, the tank has been in service for 16 years with no measurements taken since it was installed.

RCA = .342 N = .015

Interval

RCA

N

=

2

(67)

Find “S” when tmin, D, H, G, and E are known where: D=78, H=29, G = 1, E=.85, and tmin =.602

t

DHG

SE

min

.

=

2 6

Problem #2

Find E when D, H, G, S, G, and tmin are known where: D =128, H=60, S = 22,300 G = .87, and tmin = 1.125

t

DHG

SE

min

.

=

2 6

Problem #3

Find “D” when H, E, S, G, and tmin are known where: H=45, E=.90, S=22500, G= .7 and tmin =.9375

t

DHG

SE

min

.

=

2 6

Problem #4

Find “St” when E, Ht, D, G, and tmin are know where: E = .80, Ht = 54, D= 70, G = 1 and tmin =.4325

H

S Et

D

t t

=

min

.

2 6

Problem #5

Find “C” when D and H are know where D = 60, H = 54

C

= 014

_.

D H

2

(68)

1. Find the minimum acceptable shell plate thickness of the first course of an AST. Tmin = Minimum acceptable thickness ?

D = Nominal diameter of tank, in feet 120 H = Height of tank in feet 48 G = Specific gravity of contents 1

S = Maximum allowable stress 21000 E = Joint efficiency of tank .85

t

D H

G

SE

min

.

(

)

=

2 6

−

1 t

_min

( . )(

)(

)( )

(

)(. )

=

2 6 120 48 1 1

−

21000 85

tmin = =. " 14664 17850 8215 2. Find the corrosion rate of an AST given the following information.

Original thickness = .875” Measured thickness = .625

Years since last thickness measurement = 11

CR

t

Time

original last

=

−

CR

=

.

875 625

−

.

11 CR

=.023

3. Using the corrosion rate determined in problem number 2, what would the remaining life expectancy of this tank be if the minimum required thickness is 0.436”?

RL

t

CR

actual imum

=

−

min

RL

=

.

−

.

625 436

023 RL

= 8 2

.

years

4. Shell settlement evaluation measurements are to be taken on a 146 feet diameter AST. Given the following formula, how many elevation measurements would be required?

N

=

D

10 N

=

146

10 N

=

14 6 15

.

=

5. Using the information in number four, does this number meet the requirements of API-653, which does not permit the measurement points to exceed 32 feet?

API 653 Vol 1

* STORAGE TANK INSPECTOR *

COURSE NOTES

VOLUME - 1

CONDUCTED FOR

Reliance Industries Limited

Navi Mumbai

CONDUCTED BY

Asian Training Academy, Pune.

API 653- STORAGE TANK INSPECTOR

PREPARATORY COURSE

CONDUCTED BY

Asian Training Academy, Pune.

Statement

Asian Training Academy, Pune

API 653- STORAGE TANK INSPECTOR PREPARATORY COURSE

VOLUME-1

CONTENTS

1. Program Schedule

2. PART 1 - Examination/Certification Information from API.

3. PART II- Guidelines and useful tips for Examination

4. PART III- Case Studies- WPS/PQR Roadmap & Examples

5. PART IV- Mathematics in API 653 Exam.

API 653- STORAGE TANK INSPECTOR PREPARATORY COURSE

API 653- STORAGE TANK INSPECTOR

PREPARATORY COURSE

PART I

EXAMINATION/CERTIFICATION

INFORMATION

FROM API.

Asian Training Academy, Pune.

API 653 CERTIFICATIN FOR IN-SERVICE INSPECTION

INTRODUCTION

1. Preamble:

Storage Tanks are the major installations in Petroleum Refineries, Petrochemical

plants, Oil terminals and other process plants. They store variety of fluids, which

may be Explosive, Corrosive or Toxic in nature. The equipments are also subjected to

fluid head pressures and moderate temperatures. All these factors may cause

corrosion and other damages to the vital equipments.

The corrosion may cause thinning, pitting or cracking of tank walls. The internal

head will tend to bulge the tanks or piping at the corroded locations, releasing the

explosive or toxic contents resulting in serious consequences to the plant, personnel

and the people at large. It is therefore essential that during the planned shutdowns,

the degradation and damages inflicted to the Plant equipment, Piping and Tanks

should be monitored and evaluated so as to arrive at the ‘3R’ decisions. i.e.’

Run-Repair-Replace” decisions.

More specifically, these courses describe the essentials of what to inspect, where to

inspect, how much to inspect and what to accept so as to evaluate the safety and

mechanical integrity of in-service equipments. The courses also cover methods of

repair, alteration, re-rating and replacements of affected equipments.

2. Course objectives:

The API Courses provide the participants the guidelines and methodology of

carrying out inspection of “in-service” equipments. It also provides techniques for

the assessment of the wear and tear of the equipments as well as to measure

de-gradation and damages caused to the process equipments due to the process

conditions.

If the assessment indicates that the equipment is safe to run, the participants are

further taught how to estimate the safe remaining life and the methods to extend the

useful life of the equipments.

If the decision is that the equipment needs repair, the course teaches the

participants, how to carry out such repairs of the damaged part without causing

damage to the whole equipment. It also covers the methods of re-rating the

equipment by evaluating the mechanical integrity if it is not possible to restore the

equipment to its original design conditions.

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