API 653 Exam Chapter 17

1.

Q1. Atmospheric corrosion
As a practical rule, atmospheric corrosion:

2.

Q2. Repair of defective welds
Which of the following imperfections must always be repaired?

3.

Q3. Isolated pitting
How many pits of less than half the minimum required wall thickness, each of 0.25 in diameter is allowed in an 8 in a vertical line of corrosion on a tank?

4.

Q4. Calculation of test stress: upper courses
A shell material on an existing tank has a yield strength of 32 000 psi and UTS of 60 000 psi. What is the maximum allowable hydrostatic test stress for the material for use in the upper courses?

5.

Q5. API 653: reconstruction: under bead cracking
When welding attachments to API 650 groups IV, IVA, V, or VI materials, care must be taken to avoid

6.

Q6. Hot taps
Which of the following statements is true concerning hot taps?

7.

Q7. Brittle fracture risk
What is the maximum thickness of shell plate material of a tank designed for a temperature of 50 8F before a hydro test is required?

8.

Q8. Corrosion of a vertical weld
What is the minimum remaining thickness allowed in a corroded area located on a vertical weld in a tank built-in 1980?

9.

Q9. RT of shell repairs
A 12 in long repair is made to a tank shell vertical butt weld.
How much of the repair requires radiography after the repair?

10.

Q10. E value for shell assessment
When evaluating the retirement thickness of a 3/8 inch shell plate in which the corrosion is 1 in away from a weld but the material is unknown, the value used for joint efficiency (E) shall be:

11.

Q11. Welder qualifications
A welder is qualified in vertical downhill welding for a SMAW procedure. If an inspector finds this welder welding vertically uphill, what should the inspector do

12.

Q12. Repair and alterations of storage tanks
Which of these activities is defined as a major repair/major alteration of a storage tank? In none of these activities is the foundation of the tank disturbed

13.

Q13. Operation at elevated temperatures
A tank made to API 650 of unknown low carbon steel is designed to operate at an elevated temperature of 300 ℉. What is the correct allowable stress value that should be used in the calculations for the lower courses?

14.

Q14. 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 allowable thickness for the bottom annular plate?

15.

Q15. API 653: repairing tank bottoms
What is the minimum size permitted for a welded-on patch plate on a tank bottom?

16.

Q16. MT temperature limitations
The maximum surface temperature for dry magnetic particle testing of weldments is:

17.

Q17. Edge settlement repairs
For tanks that show excessive edge settlement, which plates should be replaced, rather than repaired?

18.

Q18. Subsequent inspection periods
Following an inspection, a tank has been subjected to an RBI assessment. The maximum allowable internal inspection period allowed is:

19.

Q19. Chloride SCC temperatures
Chloride SCC of 300-series stainless steel occurs above a metal temperature of about:

20.

Q20. Minimum thickness of the annular ring
The minimum allowable thickness of a tank annular ring is:

21.

Q21. Addition or replacement of shell penetrations
A new nozzle is to be installed in an existing shell. The nozzle is 1 in NPS and the shell is 3/8 in thick. How must the nozzle be installed?

22.

Q22. Acceptable future life with a known corrosion rate
A 50-year-old riveted oil tank has the following data:
. Diameter = 115 ft and height = 50 ft
. Oil density = 875 kg/m3
. Material: unknown
. Rivet arrangement: double-row lap-jointed
. Shell lower course has thinned from 1.3 into 1.0 in since new
When should the next UT shell thickness checks be done?

23.

Q23. CUI prevention/mitigation
Which of these would significantly reduce the risk of the occurrence of CUI on a 316 stainless steel tank component system fitted with standard mineral wool lagging?

24.

Q24. Shell evaluation formula
A freshwater tank has the following data:
. Diameter = 100 feet
. Height = 30 feet
. Allowable stress in lower shell course = 24.8 ksi
. Joint efficiency E = 0.8
What is the minimum allowable (corroded) thickness of the lower shell plate course (ignore isolated pitting)?

25.

Q25. Floor repairs using lap patches
A lap patch has been used to effect a permanent repair of the floor plate of a storage tank. The repair procedure shows that the patch crosses an existing floor seam weld and that the weld on the lap patch running parallel to the floor seam is 2 inches from it. What should the inspector do?

26.

Q26. Maximum settlement Bα at angle α to the tank shell
An API inspector is inspecting a 100-foot diameter storage tank and discovers an approximately circular area of settlement near the tank shell 3.5 in ‘deep’ extending from the tank shell, about 4 feet towards the tank center. The existing welds on the floor are at 25° from the tank centreline. What should the inspector do?

27.

Q27. Measuring settlement during a hydro test
How many settlement measurement points are required during a hydro test, compared to the ‘out-of-service’ requirement specified in API 653 appendix B?

28. Q28. API 653: settlement points
How many inspection points around the circumference are required to carry out a survey for a very large tank 280 ft in diameter?

29.

Q29. API 650: methods of inspecting joints
What is the maximum difference in design thickness that API 650 allows between plates classed as the same thickness for radiographic purposes?

30.

Q30. API 650: methods of inspecting joints
What is the minimum length of the weld (remote from intersections) that must be shown on a radiograph?