Understanding API ICP653 Reading 14-Worksheet-10A

Charlie Chong/ Fion Zhang

AST Tanks 


AST Tanks 



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Fion Zhang at Shanghai 

22 nd March 2016

API 653 Exam Administration -- Publications 

Effectivity Sheet FOR: November 2015, March 

2016 and July 2016 

Listed below are the effective editions of the publications required for this 

exam for the date(s) shown above. 

API Recommended Practice 571, Damage Mechanisms Affecting Fixed Equipment in 

the Refining Industry, Second Edition, April 2011 


API 653 Exam Administration -- Publications 

Effectivity Sheet FOR: November 2015, March 

2016 and July 2016 

Listed below are the effective editions of the publications required for this 

exam for the date(s) shown above. 

API Recommended Practice 571, Damage Mechanisms Affecting Fixed Equipment in 

the Refining Industry, Second Edition, April 2011 


ATTENTION: Only the following sections / mechanisms from RP 571 are 

included on the exam: 

Section 3, Definitions 

Par. 4.2.7 Brittle Fracture 

4.2.16 Mechanical Fatigue 

4.3.2 Atmospheric Corrosion 

4.3.3 Corrosion Under insulation (CUI) 

4.3.8 Microbiologically Induced Corrosion (MIC) 

4.3.9 Soil Corrosion 

4.3.10 Caustic Corrosion 

4.5.1 Chloride Stress Corrosion Cracking (Cl-SCC) 

4.5.3 Caustic Stress Corrosion Cracking (Caustic Embrittlement) 

5.1.1.10 Sour Water Corrosion (Acidic) 

5.1.1.11 Sulfuric Acid Corrosion 


• API Recommended Practice 575, Inspection of Atmospheric and Low- 

Pressure Storage Tanks, Third Edition, April 2014 

• API Recommended Practice 577 – Welding Inspection and Metallurgy, 

Second Edition, December 2013 

• API Standard 650, Welded Tanks for Oil Storage, Twelfth Edition, March 

2013 with Addendum 1 (September 2014), Errata 1 (July 2013), and 

Errata 2 (December 2014). 

• API Recommended Practice 651, Cathodic Protection of Aboveground 

Petroleum Storage Tanks, Fourth Edition, September 2014. 

• API Recommended Practice 652, Lining of Aboveground Petroleum 

Storage Tank Bottoms, Fourth Edition, September 2014 

• API Standard 653, Tank Inspection, Repair, Alteration, and 

Reconstruction, Fifth Edition, November 2014. 


• American Society of Mechanical Engineers (ASME), Boiler and Pressure 

Vessel Code, 2013 Edition 

i. ASME Section V, Nondestructive Examination, Articles 1, 2, 6, 7 and 23 

(section SE-797 only) 

ii. Section IX, Welding and Brazing Qualifications (Welding Only) 

See end of this study note for API Official BOK 



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The Magical Book of Tank Inspection ICP 



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Q78. For dome roofs that are flanged, the radius of curvature is limited by the 

depth of the roof, including the crown and knuckle depth. What is the 

maximum roof depth for a shop assembled cone roof 10 feet in diameter? 

(a) 2.0" 

(b) 3.5" 

(c) 5.5" 

(d) 8.0" 

REF AP1650- J.3.5.3 (Table J-1) 

ANS: (c) 


Annex J (normative) Shop-Assembled Storage Tanks 

Table J.1b—Minimum Roof Depths for Shop-Assembled Dome-Roof 

Tanks (USC) 


Q81. For impact testing weld metal over 1½” inches how much shall the 

impact 

value be raised for each ½” inch of material? 

(a) 2 foot-pounds 

(b) 3 foot-pounds 

(c) 5 foot-pounds 

(d) 6foot-pounds 

REF: 650 7.2.2.5 or Table 2-4 

ANS: (c) 


API650: 9.2.2 Impact Tests 

9.2.2.1 Impact tests for the qualification of welding procedures shall comply 

with the applicable provisions of 4.2.9 and shall be made at or below the 

design metal temperature. 

9.2.2.2 When impact testing of a material is required by 4.2.9, 4.2.10, or 4.5.4 

impact tests of the heat-affected zone shall be made for all machine, 

automatic, and semiautomatic welding procedures. 

9.2.2.3 For all materials to be used at a design metal temperature below 10°C 

(50 °F), the qualification of the welding procedure for vertical joints shall 

include impact tests of the weld metal. If vertical joints are to be made by a 

machine, automatic, or semiautomatic process, impact tests of the heataffected 

zone shall also be made. 

9.2.2.4 When the design metal temperature is below –7°C (20 °F), impact 

tests of the weld metal shall be made for all procedures used for welding the 

components listed in 4.2.10.1, for welding attachments to these components, 

and for fabricating shell nozzles and manholes from pipe and forgings listed 

in 4.5. 


9.2.2.5 Impact tests shall show minimum values for acceptance in 

accordance with 4.2.9.3 and the following: 

a)for P-No. 1, Group 1, materials—20 J (15 ft-lbf), average of three 

specimens; 

b)for P-No. 1, Group 2, materials—27 J (20 ft-lbf), average of three 

specimens; 

c)for P-No. 1, Group 3, materials—34 J (25 ft-lbf), average of three 

specimens. 

For shell plates thicker than 40 mm (1 ½ in.), these values shall be increased 

by 7Joules (5 ft-lbf) for each 13 mm (1/2 in.) over 40 mm (1 ½ in.). 

Interpolation is permitted. 


9.2.2.6 Weld-metal impact specimens shall be taken across the weld with one 

face substantially parallel to and within 1.5 mm (1/16 in.) of the surface of the 

material. The notch shall be cut normal to the original material surface and 

with the weld metal entirely within the fracture zone. 

9.2.2.7 Heat-affected-zone impact specimens shall be taken across the weld 

and as near the surface of the material as is practicable. Each specimen shall 

be etched to locate the heat-affected zone, and the notch shall be cut 

approximately normal to the original material surface and with as much heataffected-zone 

material as possible included in the fracture zone. 9.2.2.8 

Production welding shall conform to the qualified welding procedure, but 

production-weld test plates need not be made. 


Q105. In performance qualification of pipe groove welds to ASME Section IX, 

which position requires more than two guided bend specimens for 

qualification? 

(a) 2G and 4G 

(b) 3G and 4G 

(c) 5G and 6G 

(d) 4G and 6G 

REF: Section IX, QW -452 

ANS: (c) 

Comments: 

To qualify using positions 5G or 6G, a total of four bend specimens are 

required. – Thus answer could be (c) or (d) 



GENERAL NOTE: The “Thickness of Weld Metal” is the total weld metal 

thickness deposited by all welders and all processes in the test coupon 

exclusive of the weld reinforcement. 

NOTES: 

(1) To qualify using positions 5G or 6G, a total of four bend specimens 

are required. To qualify using a combination of 2G and 5G in a single test 

coupon, a total of six bend specimens are required. See QW-302.3. The type 

of bend test shall be based on weld metal thickness. 

(2) Coupons tested by face and root bends shall be limited to weld 

deposit made by one welder with one or two processes or two welders with 

one process each. Weld deposit by each welder and each process shall be 

present on the convex surface of the appropriate bent specimen. 

(3) One face and root bend may be substituted for the two side bends. 


Q123. Material specifications listed in Section 2 of API 650 but not listed in 

Table QW-422 of Section IX of the ASME Code shall be considered as P1 

material with group numbers assigned according to the following. 

(a)Less than or equal to 60 kips per square inch---Group l 

(b)Greater than 60 kips per square in. but less than or equal to 75 kips per 

square inch----Group·2 

(c)Greater than 75 kips per square inch----Group 3 

(d)All the above. 

REF: 650 7.2.1.3 

ANS: (d) 


9.2.1.3 Material specifications listed in Section 4 of this standard but not 

included in Table QW-422 of Section IX of the ASME Code shall be 

considered as P-No. 1 material with group numbers assigned as follows 

according to the minimum tensile strength specified: 

a)less than 485 MPa (70 ksi)—Group 1; 

b)equal to or greater than 485 MPa (70 ksi) but less than 550 MPa (80 ksi)— 

Group 2; 

c)equal to or greater than 550 MPa (80 ksi)—Group 3. 

Separate welding procedures and performance qualifications shall be 

conducted for A841M/A841 material. 

Comment: 

•

9.2.1.4 Welding variables (including supplementary essential variables when 

impact tests are required by 9.2.2), as defined by QW-250 of Section IX of the 

ASME Code, shall be used to determine the welding procedure specifications 

and the procedure qualification records to be instituted. In addition, when 

impact tests of the heat-affected zone are required, the heat-treated condition 

of the base material shall be a supplementary essential variable. Plates 

produced by the controlled-rolled process (TMCP?) are not to be considered 

as having received any heat treatment. If a protective coating has been 

applied to weld edge preparations, the coating shall be included as an 

essential variable of the welding procedure specification, as required by 

7.2.1.9. 


Q129. On an initial in-service riveted shell inspection of vertical seams: 

(a) dimension & sketch the pattern 

(b) record the number of rows, rivet size, pitch length 

(c) note whether butt or lap riveted 

(d) all of the above 

REF: API 653, Appendix C.1.2.3 (e) 

ANS: (d) 


C.1.2.3 Riveted Shell Inspection 

a)Inspect external surface for rivet and seam leaks. 

b)Locate leaks by sketch or photo (location will be lost when shell is abrasive 

cleaned for painting). 

c)Inspect rivets for corrosion loss and wear. 

d)Inspect vertical seams to see if they have been full fillet lap-welded to 

increase joint efficiency. 

e)If no record exists of vertical riveted seams, dimension and sketch (or 

photograph) the rivet pattern: number of rows, rivet size, pitch length, and 

note whether the joint is butt-riveted or lap-riveted. 


Q137. Plate for shells, roofs and bottoms may be ordered on an 

(a) edge-thickness basis 

(b) weight basis 

(c) nominal thickness 

(d) both(a) and(b) 

REF API 650 2.2.1.2 

ANS: (d) 


4.2 Plates 

4.2.1 General 

4.2.1.1 Except as otherwise provided for in 4.1, plates shall conform to one of 

the specifications listed in 4.2.2 through 4.2.6, subject to the modifications 

and limitations in this standard. 

4.2.1.2 Plate for shells, roofs, and bottoms may be ordered on an edgethickness 

basis or on a weight (kg/m 2 [lb/ft 2 ]) basis, as specified in 4.2.1.2.1, 

4.2.1.2.2, and 4.2.1.2.3. 

4.2.1.2.1 The edge thickness ordered shall not be less than the computed 

design thickness or the minimum permitted thickness. 

4.2.1.2.2 The weight ordered shall be great enough to provide an edge 

thickness not less than the computed design thickness or the minimum 

permitted thickness. 

4.2.1.2.3 Whether an edge-thickness or a weight basis is used, an underrun 

not more than 0.3 mm (0.01 in.) from the computed design thickness or the 

minimum permitted thickness is acceptable. 


Q160. The "L" in actual thickness determination for each shell course: 

(a) may be greater than 40" 

(b) is valid only when corroded area is less than 40" 

(c) applies even if corroded area is greater than L 

(d) requires converting "D" from feet to inches 

REF: AP1653, 2.3.2.1 See Note 

ANS: (c) 


246. What is the minimum permissible design metal temperature for a 280 

foot diameter tank, 75 feet high, tank radius is 1,680 inches, plate material 

ordered is 1.125 " (including corrosion allowance) A 516-55 as rolled, killed 

fine-grain practice without impact testing. 

(a) + 8 

(b) 0 

(c) - 4 

(d) All Material must be impact tested 

REF: API 650-2.2.9.2 (Fig. 2-1) 

ANS: (c) (-2?) 




Q259. What percentage of selected spot radiography shall be at junctions of 

vertical and horizontal joints? 

(a) 15% 

(b) 20% 

(c) 25% 

(d) 50% 

REF: API 650- 6.1.2.2 

ANS: (c) 

Notes: 1. Vertical spot radiograph in accordance with 8.1.2.2, Item a: one in 

the first 3 m (10 ft) and one in each 30 m (100 ft) thereafter, 25 % of which 

shall be at intersections. 


Q15. During an internal inspection of a tank, pitting that measures 0.30 inches 

deep was found in the shell (0.625 Thickness). The required thickness of the 

shell in this area is 0.5 inches. Based on the above information should a 

repair be made? 

a) Yes 

b) No 

c) The inspector option 

d) Repair Contractor's option 

REF: API 653- 4.3.2.2 

ANS: (b) 

4.3.2.2 Widely scattered pits may be ignored provided that: 

a. no pit depth results in the remaining shell thickness being less than onehalf 

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). 


Q61. Per API 650, external floating roof deck plates having support leg or 

other rigid penetrations closer than __ inches to lap weld seams must be full 

fillet welded not less than 2 inches on 10 inch centers. 

1. 6 

2. 12 

3. 14 

4. 18 

ANS: 2 

API650: C.3.3.3 Deck plates shall be joined by continuous full-fillet welds on 

the top side. On the bottom side, where flexure can be anticipated adjacent to 

girders, support legs, or other relatively rigid members, full-fillet welds not less 

than 50 mm (2 in.) long on 250 mm (10 in.) centers shall be used on any plate 

laps that occur within 300 mm (12 in.) of any such members. A minimum of 

three fillet welds shall be made. 


Q69. What preparation is required to base metal before welding on tanks that 

have surface in contact with leaded gasoline? 

1. Scrape down to bare metal 6" (150 cm) 

2. Scrape down to bare meta 12" (300 cm) 

3. Abrasive blast any immediate areas affected 

4. Steam clean any immediate areas affected 

ANS: 2 

API2015: 12.4.2 Hot Work Permit 

In addition to the requirement for an entry permit, a qualified person shall 

issue a hot work permit to conduct hot work inside or around a tank that 

has been in leaded service. 

12.4.2.1 The qualified person issuing the hot work permit shall require that 

surfaces of tanks that have been in contact with leaded gasoline, lead 

additives or products containing lead be cleaned, scraped or wire brushed 

down. The qualified person shall assure that bare metal covers an area at 

least 12 inches (30 centimeters) surrounding any area that may be subject 

to excessive heat exposure from welding or other hot work operations. 


Q71. The maximum reinforcement thickness for vertical butt joints, less than 

or equal to 1/2“ thick is __ 

API653: Table 10.1—Max. Thicknesses on New Welds 

API650: 8.5.2 (d) 


103. What is the maximum allowable misalignment on a 3/4" vertical butt joint? 

1. 10% 

2. 1/16" 

3. 10% or maximum of 1/8" 

4. 12% or maximum of 3/32“ 

ANS: 1 (or 3?) 


API650: 7.2.3 Shells 7.2.3.1 Plates to be joined by butt welding shall be 

matched accurately and retained in position during the welding operation. 

Misalignment in completed vertical joints for plates greater than 16 mm (5/8 

in.) thick shall not exceed 10 % of the plate thickness or 3 mm (1/8 in.), 

whichever is less; misalignment for plates less than or equal to 16 mm (5/8 in.) 

thick shall not exceed 1.5 mm (1/16 in.). 

7.2.3.2 In completed horizontal butt joints, the upper plate shall not project 

beyond the face of the lower plate at any point by more than 20 % of the 

thickness of the upper plate, with a maximum projection of 3 mm (1/8 in.); 

however, for upper plates less than 8 mm (5/16 in.) thick, the maximum 

projection shall be limited to 1.5 mm (1/16 in.). 

7.2.3.3 The upper plate at a horizontal butt joint shall have a 4:1 taper when 

its thickness is more than 3 mm (1/8 in.) greater than the lower plate. 


Q111. Dual-element transducers can have the ability to operate from thin 

sections of: 

1. 1.000- 2.000 inch 

2. 2.000 - 3.000 inch 

3. 0.005- 0.009 inch 

4. 0.050 - 1.000 inch 

ANS: 4 


API575: Annex A 

(normative) 

Selected Non-destructive Examination (NDE) Methods 

A.1 Ultrasonic Thickness (UT) Measurement 

It is recommended that the ultrasonic instrument have an “A Scan” display 

with a digital readout. UT measurement should be performed using a 

transducer with characteristics appropriate for the particular test to be 

performed. Dual-element transducers are frequently selected, and they are 

available with many different operating ranges. 

Dual element transducers may have the ability to measure thin sections from 

0.050 in. to 1.000 in. (1.3 mm to 25 mm). The limitations of transducers that 

should be recognized are that their range is finite and that the transducer 

frequency must be high enough to measure thin sections accurately. Holes in 

the material or sections of less than 0.050 in. (1.27 mm) will provide either no 

reading or a false reading when measured with too low a frequency. 


Q118. In order to be in compliance with API 2207, when must the work area 

be monitored for oxygen deficiency and combustible and toxic atmospheres? 

1. Every 4 hours 



4. While work is in progress 

ANS: 4 


Q119. You are adding a 6 inch blending nozzle to the bottom course, the shell 

is 5/8" thick. What size insert plate is required when used with a 

reinforcement plate? 

1. 12" diameter 

2. 18" diameter 

3. Three times the diameter of the penetration 

4. The diameter of the reinforcement plate, plus 12“ 

ANS: 4 

9.8.6 Penetrations larger than 2 in. NPS shall be installed with the use of an 

insert plate if the shell plate thickness is greater than ½ in. and the shell 

plate material does not meet the current design metal temperature criteria. In 

addition, the following requirement shall be met: 

a) the minimum diameter of the insert plate shall be at least twice the 

diameter of the penetration or the diameter plus 12 in., whichever is 

greater; 

b) when reinforcing plates are used, the minimum diameter of the insert plate 

shall equal the diameter of the reinforcing plate plus 12 in. 


Discussion on Question 119 


Q120. Who is responsible for compliance with the API 650 standards? 

1. Manufacturer 

2. Purchaser/Owner 

3. State Inspector 

4. API 653 Inspector 

ANS: 1 

Q120A. Who is responsible for compliance with the API 653 standards? 

1. Manufacturer 

2. Purchaser/Owner 

3. State Inspector 

4. API 653 Inspector 

ANS: 2 


Happy Holi 


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Happy Holi 


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Q11. With the exception of GTAW, what P-Nos. are prohibited in the 

qualification of welders by radiography? 

(a) P-2X, P-4X, and P-5X 

(b) P-2X, P-3X, and P-5X 

(c) P-2X, P-5X, and P-6X 

ANS: c 

QW-304 


QW-304 Welders 

Except for the special requirements of QW-380, each welder who welds 

under the rules of the Code shall have passed the mechanical and visual 

examinations prescribed in QW-302.1 and QW-302.4 respectively. 

Alternatively, welders may be qualified by volumetric NDE per QW-191 when 

making a groove weld using SMAW, SAW, GTAW, PAW, and GMAW (except 

short-circuiting mode for radiographic examination) or a combination of these 

processes, except for P-No. 21 through P-No. 26, P-No. 51 through P-No. 53, 

and P-No. 61 through P-No. 62 metals. (note: P-2X/P-5X/P-6X) 

Welders making groove welds in P-No. 21 through P-No. 26 and P-No. 51 

through P-No. 53 metals with the GTAW process may also be qualified by 

volumetric NDE per QW-191. 

The volumetric NDE shall be in accordance with QW-302.2. A welder 

qualified to weld in accordance with one qualified WPS is also qualified to 

weld in accordance with other qualified WPSs, using the same welding 

process, within the limits of the essential variables of QW-350. 


Q13. Failure of any portion of a combination test in a single test coupon 

constitutes failure of the entire combination. 

(a) True 

(b) False 

ANS: a 

QW-306 


QW-306 Combination of Welding Processes 

Each welder or welding operator shall be qualified within the limits given in 

QW-301 for the specific welding process( es) he will be required to use in 

production welding. A welder or welding operator may be qualified by making 

tests with each individual welding process in separate test coupons, or with a 

combination of welding processes in a single test coupon. 

Two or more welders or welding operators, each using the same or a different 

welding process, may be qualified in combination in a single test coupon. For 

combination qualifications in a single test coupon, the limits for thicknesses of 

deposited weld metal, and bend and fillet testing are given in QW-452 and 

shall be considered individually for each welder or welding operator for each 

welding process or whenever there is a change in an essential variable. A 

welder or welding operator qualified in combination on a single test coupon is 

qualified to weld in production using any of his processes individually or in 

different combinations, provided he welds within his limits of qualification with 

each specific process. 

Failure of any portion of a combination test in a single test coupon constitutes 

failure of the entire combination. 


Q1. A manufacturer is qualifying a WPS in GMAW process in short circuit arc 

transfer mode. The test coupon is ½" thick the maximum thickness qualified 

for the WPS would be, 

(a) 0.5" 

(b) 0.275" 

(c) 0.25" 

ANS: 1" 

QW-403.10 For the short-circuiting transfer mode of 

the gas metal-arc process, when the qualification test coupon 

thickness is less than 1⁄2 in. (13 mm), an increase in 

thickness beyond 1.1 times that of the qualification test coupon. For 

thicknesses of 1⁄2 in. (13 mm) and greater, use 

table QW-451.1 or table QW-451.2, as applicable. 



Q2. Under what conditions may a WPS that has been qualified without notch 

toughness may be used for applications where they are applicable? 

(a) Qualification without notch toughness qualifies the procedure with notch 

toughness requirements. 

(b) After the procedure has been requalified to include the notch toughness 

requirements. 

(c) After preparing an additional test coupon using the same essential 

variables, but additionally with all the required supplementary essential 

variables, in a coupon long enough to provide the necessary specimens. 

ANS: c 

QW-401.3 


QW-401.3 Supplementary Essential Variable 

(Procedure). A change in a welding condition which will affect the notchoughness 

properties of a weldment (for example, change in welding process, 

uphill or down vertical welding, heat input, preheat or PWHT, etc.). 

Supplementary essential variables are in addition to the essential variables 

for each welding process. 

When a procedure has been previously qualified to satisfy all requirements 

other than notch toughness, it is then necessary only to prepare an additional 

test coupon using the same procedure with the same essential variables, but 

additionally with all of the required supplementary essential variables, with the 

coupon long enough to provide the necessary notch-toughness specimens. 

When a procedure has been previously qualified to satisfy all requirements 

including notch toughness, but one or more supplementary essential variable 

is changed, then it is only necessary to prepare an additional test coupon 

using the same welding procedure and the new supplementary essential 

variable(s), with the coupon long enough to provide the necessary notchtoughness 

specimens. 


If a previously qualified weld procedure has satisfactory notch toughness 

values in the weld metal, then it is necessary only to test notch-toughness 

specimens from the heat affected zone when such are required. 

When essential variables are qualified by one or more PQRs and 

supplementary essential variables are qualified by other PQRs, the ranges of 

essential variables established by the former PQRs are only affected by the 

latter to the extent specified in the applicable supplementary essential 

variable (e.g., essential variable QW-403.8 governs the minimum and 

maximum thickness of base metal qualified. When supplementary essential 

variable QW-403.6 applies, it modifies only the minimum thickness qualified, 

not the maximum). 


Q7. The test coupon for a PQR consisted P5A to P4 materials when notch 

toughness is not a factor, the base metals qualified would be; 

(a) P-No.5A to P-No.4 only 

(b) P-No.5A to P-No.4, P-No.3, and P-No.1 

(c) P-No.5A to P-No.5A and P-No.4 to P-No.4 

(d) None of the above 

ANS: b 

QW-424.1 


QW-424 Base Metals Used for Procedure 

Qualification 

QW-424.1 Base metals are assigned P-Numbers in table QW/QB-422; Metals that do 

not appear in table QW/QB-422 are considered to be unassigned metals except as 

otherwise defined for base metals having the same UNS numbers. Unassigned metals 

shall be identified in the WPS and on the PQR by specification, type and grade, or by 

chemical analysis and mechanical properties. The minimum tensile strength shall be 

defined by the organization that specified the unassigned metal if the tensile strength 

of that metal is not defined by the material specification. 


Q9. What production base metals is a welder qualified to weld if a P No.8 

base metal was used in his qualification? 

(a) P-No.1 through P-No.11 P-No.34 and P-No.4x to same. 

(b) P-No.1 through P-No.8 and P-No.4x to same 

(c) P-No.1 through P-No.8 to same 

(d) P-No. 8 to P-No. 8 

ANS: a 

QW-423.1 


QW-423.1 


Q1 . When qualifying a welder at 6G position using a 6" schedule 40 (0.280") 

pipe test coupon, the required type and number of tests are: 

(a) One face bend test and one root bend test 

(b) Two side bend tests 

(c) Either two face and two root bend tests or four side bent tests 

(d) Two face and two root bend tests 

ANS: d 

QW-452-1 

Note 1 

(1) To qualify using positions 5G or 6G, a total of four bend specimens are 

required. To qualify using a combination of 2G and 5G in a single test coupon, 

a total of six bend specimens are required. See QW-302.3. The type of bend 

test shall be based on weld metal thickness. 


Q50. You are reviewing a WPQ (QW-484) for a welder testing in the 6-G 

position; on SA-53 grade B pipe (TS-60,000 psi). The test results indicate the 

following: 

#1 Tensile developed 51,000 psi, broke in the weld 

#2 Tensile developed 56,900 psi, broke in base metal 

#1 Transverse root bend satisfactory 

#2 Transverse face bend satisfactory 

Will these test qualify the welder? 

A. Yes 

B. No 

C. Not enough information given 

D. Tension test is acceptable but #1 is unacceptable 

ANS: A 


Q31. Welding electrodes are grouped in Section IX by 

A. AWS class 

B. ASME specification 

C. SFA 

D. "F" number 

ANS: D 

QW-430 F-NUMBERS 

QW-431 General 

The following F-Number grouping of electrodes and welding rods in table QW-432 is 

based essentially on their usability characteristics, which fundamentally determine 

the ability of welders to make satisfactory welds with a given filler metal. This 

grouping is made to reduce the number of welding procedure and performance 

qualifications, where this can logically be done. The grouping does not imply that 

base metals or filler metals within a group may be indiscriminately substituted for a 

metal that was used in the qualification test without consideration of the 

compatibility of the base and filler metals from the standpoint of metallurgical 

properties, postweld heat treatment design and service requirements, and 

mechanical properties. 


QW-432 

F-NUMBERS 

Grouping of Electrodes and Welding Rods for Qualification 


Q93. For P-11 materials, weld grooves for thicknesses_____ shall be 

prepared by thermalprocesses, when such processes are to be employed 

during fabrication. 

A. Less than 5/8 inch 

B. 5/8 inch 

C. 1 inch 

D. 1-114 inches 

E. None of the above 

ANS: b 

QW-410.64 For vessels or parts of vessels constructed with P-No. 11A and 

P-No. 11B base metals, weld grooves for thickness less than 5/8 in. (16 mm) 

shall be prepared by thermal processes when such processes are to be 

employed during fabrication. This groove preparation shall also include back 

gouging, back grooving, or removal of unsound weld metal by thermal 

processes when these processes are to be employed during fabrication. 



Q12. What is the minimum dimension and minimum required corner radius for 

a replacement shell insert plate in a bottom shell course that is 1.750 

inches thick? 

A) 21 inches is the minimum dimension and there must be at least a 10.5 inch 

radius 

B) 12 inches is the minimum dimension and there must be at least a 6 inch 

radius 

C) 21 inches is the minimum dimension and there must be at least a 2 inch 

radius 

D) 8.75 inches (minimum) and there must be at least a 2 inch radius 

Ans = A (653, Par. 9.2.2.1 & Fig 9.1) 12 in. or 12t (use greater = 21 in.) and 

minimum radius = Dimension R = Greater of 6 inches or 6 t … In this case, 

it’s a 10.5 inch radius. 


9.2.2 Minimum Dimensions of Replacement Shell Plate 

9.2.2.1 The minimum dimension for a replacement shell plate is 12 in. or 12 

times the thickness of the replacement plate, whichever is greater. 

The replacement plate may be circular, oblong, square with rounded corners, 

or rectangular with rounded corners except when an entire shell plate is 

replaced. See Figure 9.1 for typical details of acceptable replacement shell 

plates. 



Q15. A roof-to-shell joint is considered frangible IF: 

A) It is attached to top angle of tank with a continuous fillet weld all around on 

the top 

B) It is attached to the top angle of the tank with an intermittent fillet weld all 

on the top 

C) It will fail prior to shell-to-bottom joint in the event of excessive internal 

pressurization 

D) The joint slope does not exceed 2:12 & support members are not directly 

attached to roof 

Answer: C … Reference (API 653, Para. 4.2.2.2 & API 650, Section 5.10.2.6) 

Q16. Tank material may likely satisfy the recognized toughness if it was 

constructed: 

A) To 5th Edition of API 650 (App A) 

B) To 5th Edition of API 650 (App C) 

C) To 5th Edition of API 650 (App G) 

D) To 5th Edition of API 650 (App H) 

Answer: C … Reference (API 653, Para. 3.21 & Para. 5.3.2) 


Q17. What are the required spacings between an existing nozzle (NPS 12 with 

reinforcement) located to the left side of a proposed hot tap nozzle (NPS 12 

with reinforcement also) and a vertical shell weld (located to the right side of 

the proposed hot tap location? Information: UT scan of proposed hot tap 

location in first shell course revealed no laminations. A vertical weld to the 

right of proposed hot tap location = 100% radiographed and no horizontal 

welds are in the immediate area. Tank diameter is 90 feet and the shell plate 

on the first course in the proposed area of the hot tap measures 0.750 inches. 

Formula = square root of RT is used. 

A) Spacing = 10 in. between both nozzle repad (and hot tap nozzle repad) and 

the vertical weld 

B) Spacing = 20 in. between nozzle repad (and hot tap nozzle repad) and 12 in. 

(?) to vertical weld 

C) Spacing = 28 in. between both nozzle repad (and hot tap nozzle repad) and 

the vertical weld 

D) Spacing = 10 inches between nozzle repad (and hot tap nozzle repad) & 6 in. 

to vertical weld 

Answer: B (Reference: API 653, Section 9.14.3.1 & Figure 9.10 

√(RT) = √(540x0.750) = 20.12” 

Correct answer = 20” & 10”? 


API650: Figure 5.6—Minimum Weld Requirements for Openings in Shells According to 5.7.3 


Q 26. Determine the minimum acceptable thickness of a shell plate (bottom 

course) in a 200 foot diameter 50 foot high Oil Storage tank (maximum 

liquid level = 48 ft) having a Designed Specific Gravity of 1.00 constructed 

per API 650, 1st Edition, 1961, Basic Standard, using A283 Gr. C shell 

material of 1.500 inch thickness? 

A) 1.034 inches 

B) 1.218 inches 

C) 1.244 inches 

D) 1.250 inches 

Answer = B … 

t min = 2.6(H-1)DG/SE = 2.6(47)200/(23600) = 1.036 


Q 26. Determine the minimum acceptable thickness of a shell plate (bottom 

course) in a 200 foot diameter 50 foot high Oil Storage tank (maximum 

liquid level = 48 ft) having a Designed Specific Gravity of 1.00 constructed 

per API 650, 1st Edition, 1961, Basic Standard, using A283 Gr. C shell 

material of 1.500 inch thickness? 





Answer = B … 

t min = 2.6(H-1)DG/SE = 2.6(47)200/(23600 x 0.85) = 1.218 



Q27. Determine minimum acceptable thickness of a generally corroded 3rd 

course shell plate (Tank has 5 shell courses and each course measures 10 ft) 

with a tank diameter of 150 foot, in Oil Service (Maximum Liquid Level = 48 ft) 

with Specific Gravity of 1.00 constructed per API 650, 7th Edition using Spot 

RT, with shell material construction of A516 Gr. 70)? 





Answer = D … 

t min = 2.6(28)150/(33000x 0.85) = 0.389” (be careful!) 

t min = 2.6(28-1)150/(33000x 0.85) = 0.375” (correct!) 



Q31. The maximum dimension along the shell for a welded on patch plate in 

critical zone is: 

A) 12 inches 

B) 24 inches 

C) 48 inches 

D) 72 inches 

Ans: B (Ref API 653, Para. 9.10.1.1 & Figure 9.9 & CRITICAL NOTE 3) 

Q32. The maximum thickness for a welded on patch plate in the critical zone 

is: 

A) two inches 

B) one inch 

C) ½ of an inch 

D) ¼ inch 

Ans: D (Ref API 653, Para. 9.10.1.2.a & Figure 9.9 Sect. A-A view) ¼-in 

maximum 


NOTE 1 

Dimensions given are from toe of fillet welds or to centerline of butt-weld and also 

apply to new-to-existing welds. 

NOTE 2 

Minimum distance between two welded-on patch plates in the critical zone shall be 

one half of the lesser of L1 or L2. 

NOTE 3 

The maximum dimension along the shell for welded-on patch plates in the critical zone 

is 24 in. 

NOTE 4 

When the edge of a welded-on patch plate is approximately parallel to a bottom seam, 

the edge shall be held at least 2 in. from weld seam. 

NOTE 5 

Patches over three-plate laps shall extend a minimum of 12 in. in all directions along 

all laps beyond the three-plate lap. 

NOTE 6 

These rules apply to butt-welded bottoms, where applicable. 

NOTE 7 

Applies to shells of unknown toughness. 

Figure 9.13—Typical Welded-on Patch Plates on Tank Bottom Plates 


9.10 Repair of Tank Bottoms 

9.10.1 Repairing a Portion of Tank Bottoms 

9.10.1.1 General Repair Requirements 

The use of welded-on patch plates for repairing a portion of uniformly 

supported tank bottoms is permitted within the limitations given in this 

section and 9.10.1.2. See Figure 9.13 for acceptable details for welded-on 

patch plates. 

a. The minimum dimension for a welded-on patch plate that overlaps a 

bottom seam or existing patch is 12 in. The welded-on patch plate may be 

circular, oblong, or polygonal with rounded corners. 

b. A welded-on patch plate smaller than 12 in. in diameter is permitted if: it is 

equal to or exceeds 6 in. in diameter; it does not overlap a bottom seam; it 

is not placed fully or partially over an existing patch; and it extends beyond 

the corroded bottom area, if any, by at least 2 in. 

c. Welded-on patch plates shall not be placed over areas of the tank bottom 

that have global dishing, local dishing [except as allowed by 9.10.1.1 d)], 

settlement, or distortion greater than the limits of Annex B. 

NOTE If the tank is still undergoing settlement, the addition of welded-on 

patch plate may not be advisable. 


d. A welded-on patch plate may be placed over a mechanical dent or local 

dishing if: its unsupported dimension does not exceed 12 in. in any 

direction; it is at least 1/4 in. thick; it is at least as thick as the existing 

bottom; and does not overlap seams nor other patches, except for tanks 

designed in accordance with API 650, Annex M, which shall have weldedon 

patch plates at least 3/8 in. thick. 

e. These repairs are permanent repairs subject to an on-going inspection 

and maintenance program. 

f. Installation of a new sump shall conform to API Standard 650 Section 5, 

paragraph 5.8.7 (Water Drawoff Sumps), Tables 5-16a and 5-16b and 

Figure 5-21. 


Things to remember on bottom plate patch welding repairs: 

• The minimum patch plate ≥12” 

• Patch plate ≤ 12”, ≥6” could be used: 

If does not overlaps any bottom weld and the patch plate perimeter extend 

beyond the corroded area by 2” 

• At least ¼” for place over mechanical dent, dishing. 


9.10.1.2 Repairs within the Critical Zone 

The use of welded-on patch plates is permitted for repairing a portion of tank 

bottoms within the critical zone (see 3.10 for definition) provided 9.10.1.1 

requirements and the following additional requirements are met. 

a) Maximum plate thickness for welded-on patch plates within the critical 

zone is 1/4-in. and must meet the toughness requirements of API 650, 

Section 4.2.10. 

b) When a welded-on patch plate is within 6 in. of the shell, the welded-on 

patch plate shall be tombstone shaped. The sides of the tombstone 

shaped welded-on patch plate shall intersect the shell-to-bottom joint at 

approximately 90°. 

c) Perimeter welds on welded-on patch plates within the critical zone shall be 

two-pass, minimum, and examined per 12.1.1.3 and 12.1.7.2. 

d) Installation of a welded-on patch plate by butt-welding to an adjacent 

existing patch is not permitted in the critical zone. 

e) Welded-on patch plates over existing patches are not allowed in the 

critical zone. 


f) The bottom plate under the perimeter of a welded-on patch plate shall 

meet the thickness requirements in 4.4. (0.05” or 0.1”) 

g) For tanks with shell plate of unknown toughness as defined in Section 3, 

new fillet welds utilized to install a tombstone patch plate in the critical 

zone shall be spaced at least the greater of 3 in. or 5t from existing 

vertical weld joints in the bottom shell course, where t is the thickness of 

the bottom shell course, in inches. See Figure 9.13 for further guidance 

on weld spacing. 

NOTE The bottom plate thickness at the attachment weld must be at least 

0.1-in. thick before welding the welded-on patch plate to the bottom plate. 

Refer to API 2207 for further information. 

API RP 2207 (R2012) Preparing Tank Bottoms for Hot Work, Sixth Edition 


Things to remember on critical zone patch welding repairs: 

• The maximum patch plate ≤ 24” 

• The maximum patch plate thickness ≤ ¼” 


Q 40. Tank Bottom Release Prevention Systems per API 653 include all of 

the following EXCEPT: 

A) Internal inspection of the tank bottom 

B) Leak detection systems and leak testing of the tank 

C) Installing an area impressed current CP system for the entire tank farm 

D) Lining tank interior bottom or providing a RPB under the tank bottom 

Ans: C … Reference (API 653, Par. 4.4.3) CP must be for underside of the 

tank) 


4.4.3 Tank Bottom Release Prevention Systems (RPSs) 

API supports the use of a release prevention system (RPS) to maintain the 

integrity of tank bottoms. The term RPS refers to the suite of API standards 

and recommended practices that are designed to maintain tank integrity and 

thus protect the environment. With respect to tank bottoms, these include: 

• internal inspection of the tank bottom; 

• leak detection systems and leak testing of the tank; 

• installing cathodic protection for the underside of the tank bottom; 

• lining the bottom of the tank interior; 

• providing a release prevention barrier (RPB) under the tank bottom; or 

• some combination of these measures, depending on the operating 

environment and service of the tank. 


Discussion: 

Look similar RPS vs. RPB 

Discuss the differences 


Q57. What finished welds do NOT require stamping of ID for welder (or 

operator)? 

A) Only floor plate welds and roof plate welds and flange to nozzle-neck 

welds 

B) Only roof plate welds and flange to nozzle-neck welds do not require ID 

stamps 

C) Only flange to nozzle-neck welds do not require welder (operator) ID 

stamps 

D) None of these! Finished welds must always be stamped by a welder 

(operator) 

Answer: B … Reference (API 653, Para. 11.2.2) 


Q69. Where exterior tank bottom corrosion is controlled by a cathodic 

protection system, periodic surveys of the system shall be conducted in 

accordance with API 651. Who is responsible to review the results of 

these CP surveys? 

A) Owner/operator 

B) Authorized Inspector 

C) Storage Tank Engineer 

D) Authorized Insp Agency 

Answer: A … Reference (API 653, Par. 6.3.4.2 & API 651 Section 11.3.2) 


Q70. Where exterior tank bottom corrosion is controlled by a cathodic 

protection system, shall be conducted in accordance with API 651 how 

often? 

A) All sources of impressed current are checked at intervals not exceeding 1 

month (unless jurisdiction rules apply) and impressed current protective 

facilities inspected every 6 months 

B) All sources of impressed current are checked at intervals not exceeding 1 

month (unless jurisdiction rules apply) and impressed current protective 

facilities are to be inspected annually 

C) All sources of impressed current are checked at intervals not exceeding 2 

months (unless jurisdiction rules apply) and impressed current protective 


D) All sources of impressed current are checked at intervals not exceeding 3 

months (unless jurisdiction rules apply) and impressed current protective 


Answer: C … Reference (API 653, Par. 6.3.4.1 & API 651 Section 11.3.2) 


Q75. Where welding and hot work are involved, WHAT API DOCUMENT 

states “Except in areas specifically designated as safe for hot work, a hot 

work permit shall be obtained before starting any work that can involve a 

source of ignition.” 

A) API 2015 B) API 2201 

C) API 2217A D) API 2009 

Answer: D … Reference (API 653, Para. 1.4) New question for 2012 exams 

API RP 2009 (R2007) Safe Welding and Cutting Practices in Refineries, 

Gasoline Plants, and Petrochemicals Plants. standard by American 

Petroleum Institute 


Q77. The standard used for repairs or alterations made after original 

construction is the: 

A) As-built standard 

B) As-built standard only for those repairs or alterations 

C) Construction STD only for those repairs or alterations 

D) None of these are correct 

Ans: B … Ref (API 653, Par. 3.2 … 5th Sent of 5 in definition) New question 

2012 exams 


Q83. A condition that exists when the material of a component is deemed 

acceptable for use by provisions of many requirements for Brittle Fracture 

assessment using the decision tree: 

A) Unknown toughness 

B) Acceptable toughness 

C) Recognized toughness 

D) None of these 

Answer: C … Reference (API 653, Para. 3.21) 

Q84. Tank material may likely satisfy the recognized toughness definition if 

metal temperature operates at temperatures not less than: 

A) 50°F 

B) 60°F 

C) 70°F 

D) None of these 

Answer: B … Reference (API 653, Para. 3.21 & Para. 5.3.6) 


Q88. In order to qualify for a hydrotest exemption after a major repair or a 

major alteration, ALL OF THESE CONDITIONS FOR SHELL REPAIRS 

SHALL BE MET EXCEPT (1 statement = false): 

A) New vertical and horizontal shell butt-welds shall have complete joint 

penetration and fusion 

B) Root pass (shell t > 1 inch) shall be back gouged & examined full length 

by MT or PT methods 

C) Final weld pass (all shell thicknesses) shall be examined full length by MT 

or PT methods 

D) Finished welds shall be fully (100%) radiographed. 

Answer: C … Ref (API 653, Section 12.3.2.3.4/5) Final weld pass > 1 inch 

shall be MT’d or PT’d 


12.3.2.3.5 The root pass and final pass examination shall be in accordance 

with 12.1.5. In addition, the finished weld shall be fully radiographed. 

12.1.5 Shell Plate to Shell Plate Welds 

12.1.5.1 New full penetration welds attaching existing shell plate to existing or 

new shell plate shall be examined by radiographic methods (see 12.2). In 

addition, for plate thicknesses greater than 1 in., the back-gouged surface 

of the root pass and final pass (each side) shall be examined for its 

complete length by magnetic particle or liquid penetrant methods. 

12.1.5.2 New welds joining new shell plate material to new shell plate 

material (partial or full shell course replacement or addition) need only be 

examined radiographically in accordance with API 650, Section 8.1. 



major alteration, ALL OF THESE CONDITIONS FOR SHELLS/NOZZLES 

SHALL BE MET EXCEPT (1 statement = false): 

A) Shell welds for reinforcement-to-nozzle neck joints shall have complete 

penetration & fusion 

B) Shell welds for nozzle neck-to-shell joints shall have complete penetration 

and fusion 

C) Root pass of nozzle attachment weld shall be back-gouged and MT or PT 

examined 

D) Completed nozzle attachment welds shall also be MT or PT examined 

Answer: D … Ref (API 653, Section 12.3.2.3.6) UT SHEAR WAVE is also 

required for exemption 

12.3.2.3.6 Shell welds for the reinforcing plate-to-nozzle neck and nozzle 

neck-to-shell joints shall have complete penetration and fusion. The root 

pass of the nozzle attachment weld shall be back-gouged and examined 

by magnetic particle or liquid penetrant methods. The completed weld 

shall be examined by magnetic particle or liquid penetrant methods and by 

the ultrasonic method. Examination and acceptance criteria for NDE shall 

be in accordance with 12.1. 



major alteration, all these conditions for bottom repairs in critical zone 

shall be met except (1 statement = false): 

A) Repairs to annular ring or bottom plate meet API 653 WPS rules, impact 

test requirements, and new materials = current API 650 edition, & existing 

materials = API 650 (7th Edition or later) 

B) Annular plate butt-welds shall also be examined by radiographic methods 

after a final pass. 

C) Joints shall be examined after root and final pass by MT or PT methods 

D) Joints shall be examined visually prior to welding 

Answer: B … Ref (API 653, Sect. 12.3.2.3.4.1.a/b) Ultrasonic Testing (Shear 

Wave) is required 


Q9) A hot tap in a 1.25" thick tank with a minimum metal temperature of 65 o F 

at time of hot tap, without having material toughness data is :- 

(a) not permitted; 

(b) permitted; 

(c) not enough information; 

(d) not addressed by the code 

REF : API 653 – 7.13.4 & Fig. 7-5 

ANS : (a) 


9.14 Hot Taps 9.14.1 General 

9.14.1.1 The requirements given herein cover the installation of radial hot tap 

connections on existing in-service tanks. Hot taps are not permitted on 

shell material requiring thermal stress relief as specified in API 650, 

Section 5.7.4. 

a) For tank shell plates of recognized toughness, as defined in Section 3, the 

connection size and shell thickness limitations are shown in Table 9.1. 

b) For tank shell plates of unknown toughness, as defined in Section 3, the 

following limitations apply. 

1) Nozzles shall be limited to a maximum diameter of 4 in. NPS. 

2) The shell plate temperature shall be at or above the minimum shell 

design metal temperature for the entire hot tapping operation. 

3) All nozzles shall be reinforced. The reinforcement shall be calculated 

per API 650, Section 5.7.2. The minimum thickness of the reinforcing 

plate shall be equal to the shell plate thickness, and the minimum 

reinforcing plate diameter shall not be less than the diameter of the 

shell cutout plus 2 in. 

4) The maximum height of tank liquid above the hot tap location during 

the hot tapping operation shall be such that the hydrostatic tank shell 

stress is less than 7,000 lbf/in. 2 at the elevation of the hot tap. 


9.14.1.2 The minimum height of tank liquid above the hot tap location shall be 

at least 3 ft during the hot tapping operation. 

9.14.1.3 Welding shall be done with low hydrogen electrodes. 

9.14.1.4 Hot taps are not permitted on the roof of a tank or within the 

gas/vapor space of the tank. 

9.14.1.5 Hot taps shall not be installed on laminated or severely pitted shell 

plate. 

9.14.1.6 Hot taps are not permitted on tanks where the heat of welding may 

cause environmental cracking (such as caustic cracking or stress corrosion 

cracking). 


Q6. Cone roof storage tanks may be as large as ______ feet in diameter. 

300’ 

Q7. The simplest type of floating roof is the: 

Pan 

Q33.The simplest type of atmospheric storage tank is the: 

Cone roof 

Q12.Tank surfaces that have been in contact with leaded gasoline should be 

scraped down to bare metal. On each side of a line that might be heated 

excessively by welding or other operations, an area of at least ______ should 

be scraped down to bare metal. 

12” 


Q34. Corrosion on the underside of tank bottoms that rest on pads or on the 

soil cannot be inspected readily from the outside. If it becomes necessary to 

make an external inspection of the bottom located near the edge of the tank, 

the following method can be used when the tank is out of service. 

Tunneling method 

Q35.During an external inspection of an in-service aboveground storage tank, 

crevices associated with structural steel ladders, stair treads, and platforms 

plates, etc., where water can collect, should be closely checked by: 

Picking with a scraper or knife 

Q36. Tank bottoms should be checked thoroughly for thickness over its entire 

area. UT measurements are usually the first choice. If an UT instrument is not 

available, what other alternate non-destructive method could be used for 

quickly checking the condition of the bottom? 

Hammer testing 



Q42. Radiographs for an evaluated, repaired, or reconstructed tank shall be 

retained for:1 year 

Q43. In regard to installation of primary and secondary seals, if the roof rim 

thickness is less than _____ inch thick, it shall be replaced. 

0.10 

Q44. If it is necessary to replace a roof rim, the new roof rim shall be a min. 

thickness of: 

3/16” 

Q45. The min. thickness of new roof plates shall be: 

3/16” plus any corrosion allowance. 

Q46. Rim-mounted primary and toroidal seal systems can be removed, 

repaired, or replaced. To minimize evaporation losses and reduce potential 

hazards to workers, no more than: 1/4 of the roof seal system should be out 

of an in-service tank at one time. 


Q47. In the event roof live loads exceed 25 pounds per square foot (loads 

caused by insulation, vacuum on the tank, snow loads), the plate thickness 

shall be: Based on analysis using proper allowable stresses 

Q48.Where tank foundations true to a horizontal plane are specified and 

concrete ringwalls are not provided, the tolerances are as follows: 

Without ringwall 

The foundation under the shell shall be level with plus or minus 1/8” in any 10’ 

of circumference and within plus or minus ½” in the total circumference 

measured from the average elevation. 

With ring wall 

The foundation under the shell shall be level with plus or minus 1/8” 3’ of 

circumference and within plus or minus ¼ ” in the total circumference 

measured from the average elevation. 


Q54. What type of tank settlement does not induce stresses in the tank 

structure? It does cause problems with piping and other attachments to the 

tank from outside. 

Uniform settlement 

Q55. What type of tank settlement generally rotates the tank in a tilted plane? 

Rigid body tilting 

Q56. What type of tilt of a tank will cause an increase in the liquid level and, 

therefore, an increase in the hoop stress in the tank shell? It also can cause 

binding of seals on floating roofs. 

Rigid body tilting 

Q57. What type of tank settlement is characterized by settlement of a tank at 

different rates at different locations? This results in non-planar configurations 

which induces additional stresses in a tank shell. 

Out-of-plane settlement 


Q58. What type of tank settlement leads to a lack of circularity at the top of 

the tank, and may induce improper functioning of the floating roof? Also, flat 

spots may develop on the tank shell. 

Differential settlement (rigid body settlement?) 

Q66. Measurements to verify the dimensional tolerances of a reconstructed 

aboveground storage tank shall be taken: 

Before the hydrostatic test of the tank 

Q72. The projection of the bottom plate beyond the outside toe of the shell-tobottom 

weld shall be at least _____ inch. 

0.3750 (3/8”) 

Q77. Tank-to-soil potential measurements are typically taken with: 

The current applied 


Figure 9.1—Acceptable Details for Replacement of Shell Plate Material 


Q85. If caustic is stored in an aboveground storage tank, what would be the 

most likely problem found and where? 

Caustic embrittlement resulting in cracks in welds and HAZ’s around 

connections for internal heating units or coils. 

Q89. Prior to determining the need for cathodic protection of an aboveground 

storage tank: 

A full evaluation of tank history is advised. 

Q99. A lapped repair plate may cross any butt-welded vertical or horizontal 

shell seam that has been ground flush. How much overlap beyond the seam 

is required? 

6” 

Q100. External leaks on aboveground storage tank shells are often marked 

by a: 

Discoloration or the absence of paint in the area below the leak 


Clay Pot Rice 煲仔饭 


Q45. UT measurements are required on a tank shell, how many 

measurements shall be taken: 

Owner / operator judgment. 

Q54. When preparing a tank prior to installing a replacement bottom over an 

existing bottom, the tank shell must be separated from the tank bottom by 

cutting the shell parallel to the tank bottom a minimum of __________ above 

the bottom-to-shell weld or by removing the entire shell-to-bottom weld and 

the HAZ by gouging or grinding. 

½” 


Q56. Guidance for evaluation of an existing external floating roof shall be 

based on criteria in: 

API 650 appendix C. 

Q50. You are reviewing a WPQ for a welder. The test results indicate 

the following: 

a. Satisfactory side bend 

b. Face bend satisfactory 

c. Visual satisfactory 

Are these tests qualify the welder? 

a. Yes 

b. No, because bend tests are not correct type. 

c. Not enough information given 

d. No, because radiography is essential for welder Qualification 

ANS: B 



Good Luck!

Understanding API ICP653 Reading 14-Worksheet-10A

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