ch15 answers.pdf

Chapter 15

Answers

15.1 Familiarization answers

Subject questionand Chapter

Questionnumber

Answer

API 570(Chapter 3)

123456789101112131415

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API 574(Chapter 4)

12345

cabcc

API 574 (sections 6and 10)

(Chapter 4)

12345678910

acdbbdbcdc

API 578(Chapter 5)

123

bcc

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Questionnumber

Answer

45678910

abbcbda

API 571 (set 1)(Chapter 6)

12345678910

bccacbcbbb


12345678910

bbabddddbb


12345678910

dacabcbbdd

API 577: weldingprocess

(Chapter 7)

123

abb

Answers

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Questionnumber

Answer

45678910

addccbb

API 577: weldingconsumables(Chapter 7)

12345678910

abbaadccbd

API 570: generalwelding rules(Chapter 8)

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ASME B31.3(Chapter 8)

12345

abcba

ASME IX articles Iand II

(Chapter 9)

12345678

ccdacabb

Quick Guide to API 570

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Questionnumber

Answer

910

dc

ASME IX articles IIIand IV

(Chapter 9)

12345678910

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API 577(Chapter 10)

12345678910

ccbdabcddd

API 570 and ASMEB31.3(1)

(Chapter 10)

12345678910

addabcaacb

ASME B31.3 (2)(Chapter 10)

12345678

adbdabca

Answers

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Questionnumber

Answer

910

dc

ASME V articles 1, 2and 6

(Chapter 11)

12345

ddddc

ASME V articles 7and 9

(Chapter 11)

12345678910

badddabcaa

ASME B31.3:pressure design(Chapter 12)

123456789101112131415

bccabcabdccbcdd

ASME B16.5: angedesign

(Chapter 13)

12345678

bcdcdadc


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Questionnumber

Answer

910

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15.2 Example open-book answers

Question 1. B31.3: minimum design temperaturesB31.3 graph 323.2.1, as this is a Category D uid. Note 1 of thetable says that any carbon steel can be used down to 29 8C(ANS) (as long as its a Category D uid).

Question 2. B31.3: Barlow equationAPI 570 7.2 and using the simple Barlow equation P = 2SE t/Dfor the MAWP calculations,E= 1 for seamless, wall thickness t for a 20 in std pipe (API 574)= 0.375 in, OD (D) of pipe = 20 in, P = 2 20 000 0.375/20= 750 psi (ANS).

Question 3. Flange test pressuresB16.5 table 1A and table 2 show that A350 LF2 material is table1-1. At 250 8C, a Cl 1500 ange has a maximum workingpressure of 209.7 bar = 3041.2 psi (ANS).

Question 4. Degradation mechanismsAPI 574 section 10.2.1.5.2: suffers graphitization above 800 8F(ANS).

Question 5. B31.3: wall thickness equationsB31.3 section 304.1.2 equation 3(a). Using t = PD/[2(SE+PY)]in equation 3(a), note that for a 10 in NB pipe, the OD is10.75 in, not 10 in; S= 18.9 ksi for API 5L at 260 8C (500 8F), Y= 0.4 for ferritic steel (table 304.1.1), E = 0.85 for ERW pipefrom table 302.3.4, t = (348 10.75)/{2 [(18 900 0.85)+(348 0.4)]} = 0.115 in = 2.93 mm + 2 mm rounded up= 5 mm (ANS).

Question 6. B31.3: design stressFrom the other materials section of B31.3, 302.3.2 (d), thedesign stress shall not exceed:

. one-third of the minimum UTS at room temperature (ST)or at temperature;

Answers

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. two-thirds of the minimum yield at room temperature (SY)or at temperature,

so in this case its the lower of 4300 kPa/3 = 1433 kPa or23 2070 kPa = 1380 kPa (ANS).Question 7. B31.3: casting factorsRead from the table in B31.3 section 302.3.3c. The answer is 0.85(ANS) as no surface nish is given in the question.

Question 8. B31.3: blank thicknessUsing the blank formula in B31.3 section 304.5.3, t = d SQRT[3P/(16SE)] + c, D = 278 mm = 10.94 in, P = 670 psi, S =A182 F304L material at 400 8C (752 8F) = 13.2 ksi, t =10.94 SQRT [(3 670)/(16 13 200)] = 1.06 in = 27 mm(ANS).

Question 9. Flange test pressuresB16.5 table 1A and table 2-1.9. For a class 300 ange the tableshows a maximum temperature of 250 8C (ANS).

Question 10. B31.3: blank thicknessUsing the blank formula in B31.3 section 304.5.3, t = d SQRT[3P/(16SE)] + c, D= 10 in, P = 170 psi, S= A105 material at500 8F = 19.4 ksi, t = 10 SQRT [(3 170)/(16 19 400)] =0.4 in =10.29 mm; to go for the next size up 15 mm (ANS).

Question 11. B31.3: minimum design temperaturesB31.3 graph 323.3.2A. Curve C at 30 mm thick shows 15 8C(ANS).

Question 12. B31.3: minimum design temperaturewithout impact testingB31.3 graph 323.3.2B. Stress ratio = 62/130 = 0.467 gives atemperature reduction of 60 8F (36 8C) (ANS).

Question 13. B31.3: allowable reductions in designtemperatureB31.3 graph 323.3.2B. Stress ratio = 64/160 = 0.4 gives atemperature reduction of 60 8C (ANS).


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Question 14. B31.3: minimum Charpy valuesMethod: B31.3 section 323.3.5. Checking strength from B31.3table A-1 gives 20 ksi. Looking in table 323.3.5 for 65 ksi and lessgives a minimum Charpy value of 16 J (ANS).

Question 15. B31.3: thermal expansionFrom B31.3 appendix C table, temperature rise from 70 to 5008F gives an expansion of carbon steel (API 5L is carbon steel) of3.62 in/100 ft. Pipe is 900.68 in = 75 feet so expansion =3.62 0.75 = 2.71 in = 69 mm (ANS).Question 16. B31.3: thermal expansionFrom B31.3 appendix C table, temperature rise from 70 to950 8F gives an expansion of stainless steel (API 5L is carbonsteel) of 10.8 in/100 ft. Pipe is 1801.36 in = 150 feet so expansion= 10.8 1.5 = 16.2 in = 411 mm (ANS).Question 17. API 570: corrosion ratesMethod: API 570 section 7.2. 18 in std has wall thickness of0.375 in = 9.525 mm. A515 Gr 50 has S= 15.8 ksi at 600 8F. E= 0.6 for furnace butt welded pipe Y = 0.4 for ferritic pipe.Using t = PD/[2(SE+PY)], t = 300 18 /2 [(15 800 0.6) +(300 0.4)] = 5400/19 200 = 0.28 in = 7.14 mm. Hence it has9.525 7.14 mm = 2.385 mm to corrode at 0.254 mm/yr = 9.4years. It should be inspected after half of this = 4.7 years (ANS).

Question 18. API 570: corrosion ratesAPI 570 section 7.1.1. Hence it has 10 6 mm = 4 mm tocorrode at 0.25 mm/yr = 16 years. It should be replaced afterthis 16 years (ANS).

Question 19. Flange and pipe test pressuresMethod: B31.3 section 345.2.1. Pipe size details are not required.It is simply Pt = 1.5 PStest/Stemp = 1.5 254 = 381 psi(ANS).

Question 20. API 570: corrosion ratesMethod: API 570 section 7.1.1. Check 10 in Sch 140 has a wallthickness of 1 in = 25.4 mm. So it has corroded 10 mm in 10years = 1 mm/year (ANS).

Question 21. API 570: corrosion ratesMethod: API 570 section 7.1.1. So it has corroded 2 mm in 4years = 0.5 mm/year (ANS).

Answers

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Question 22. API 574: Barlow formulaMethod: API 574 section 11.1. Answer is (b) (ANS).

Question 23. API 574: valve wall thicknessAPI 574 section 11.2 species that a valve must have 1.5wallthickness of a pipe connected to it. Hence thickness = 1.5 10mm = 15 mm (ANS).

Question 24. API 574: anged connection thicknessAPI 574 section 11.2 species that a anged tting (like a valve)must have 1.5wall thickness of a pipe connected to it. So if theanged tting is 30 mm the pipe must be 20 mm (ANS).

Question 25. API 570: pipe classesAPI 570 table 6.1, class 1 pipe. Thickness measurements arerequired every 5 years (ANS).

Question 26. API 570: pipe classesAPI 570 table 6.1, class 2 for hydrogen. Thickness measurementsare required every 10 years (ANS).

Question 27. API 570: pipe classesAPI 570 table 6.1, class 2 for strong acids and caustics. Externalvisual is required every 5 years (ANS).

Question 28. API 570: pipe classes CUIMethod: API 570 table 6.2 and table 6.2, class 3. Requiredexamination is 25 % (ANS).

Question 29. API 570: pipe classes CUIAPI 570 table 6.2, class 1 but no damaged lagging. Requiredexamination is 50 % (ANS).

Question 30. API 570: pipe classes inspection periodAPI 570 section 6.6.1, class 2 small-bore secondary pipework.Code says inspection is optional (ANS).


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