Understanding API ICP653 Reading 11-Worksheet-7

Readings on APIICP650 Readi Re ading ng 11 - Q& Q&A A Prac Practic tices es My Pre-exam Self Study Notes 13 th March 2016

Charlie Chong/ Fion Zhang

Petroleum Upstream


Petroleum Upstream


Petroleum Upstream


API 653 Exam Administration 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: 1. Se Sect ctio ion n 3, De Defi fini niti tion onss 2. Pa Par. r. 4.2 4.2.7 .7 Br Brit ittl tlee Frac Fractu ture re 3. 4. 4.2. 2.16 16 Me Mech chan anic ical al Fa Fati tigu guee 4. 4. 4.3. 3.2 2 Atmo Atmosp sphe heri ricc Corr Corros osio ion n 5. 4. 4.3. 3.3 3 Corr Corrosi osion on Und Under er ins insul ulat atio ion n (CUI) (CUI) 6. 4.3 4.3.8 .8 Mic Microb robiolo iologic gicall ally y Induc Induced ed Corro Corrosion sion (MI (MIC) C) 7. 4. 4.3. 3.9 9 So Soil il Co Corr rros osio ion n 8. 4. 4.3. 3.10 10 Ca Caus usti ticc Cor Corro rosi sion on 9. 4.5 4.5.1 .1 Chlor Chloride ide Str Stress ess Corr Corrosi osion on Crac Crackin king g (Cl-S (Cl-SCC) CC) 10. 4.5.3 Caustic Stress Corrosion Cracking (Caustic Embrittlement) 11. 5.1 5.1.1. .1.10 10 Sour Water Water Corrosio Corrosion n (Acidic) (Acidic) 12. 5.1.1 5.1.1.11 .11 Sulfuric Sulfuric Acid Corrosion Corrosion


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API Recommended Practice 575, Inspection of Atmospheric and LowPressure 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.


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American Society of Mechanical Engineers Engi neers (ASME), Boiler and Pressure Vessel Code, 2013 Edition i. AS ASME ME Sec Secti tion on V, V, Nond Nondes estr truc ucti tive ve Exa Exami mina nati tion on,, Arti Articl cles es 1, 1, 2, 6, 6, 7 and and 23 (section SE-797 only) ii.. Se ii Secti ction on IX, IX, Wel Weldi ding ng and and Braz Brazin ing g Qual Qualif ific icati ation onss (Weld (Weldin ing g Only Only))

See end of this study note for API Official BOK


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Fion Zhang at Xitang 13th March 2016


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Q&A Practice 1 Thanks George for your good works!


Nice Job George! Charlie Chong/ Fion Zhang

Supe Su per r Mem Memor ory y – Me Memo moir ir MARCH 2014 COMPUTER MARCH COMPUTER MEMORIES MEMORIES … We’ll call call him GEORGE GEORGE HARRISON … He remembered remembered an amazing amazing 105 Qs of 150 for March 2014 2014 computerized exam and and claims Control F function was not allowed … Can you locate the Code Sections and REFERENCES ON ALL ANSWERS … THIS MAKES FUN PRACTICE … … Ni Nice ce Jo Job b Geo Georg rge e




Q1: Zn/ Cd detrimen detrimental tal to SS steel, possible possible liquid metal metal embrittlemen embrittlement. t.

Q2: Patch plate at critical zone for service temperature >200⁰F for CS, >100⁰F for SS

Q3: Critical zone repair requirements


Q4: CaSi insulation insulation material material contains contains Cl-

Q5: Act Q5: Act of penetrating a thin component

Q6: Characteristics of SAW


Calcium Silicate Insulation Boards


Q7: Welder marking on work piece

Q8: Hot tap limitation on membrane stress

Q9: Tank bottom edge settlement (both condition must be satisfied?)


Q10: Definition of Repair

Q11: Definition of Critical Zone (3 (3”” is ke key y poi point nt))

Q12: Colum wear plate (key point thickness of plate and fillet weld size = ¼”)


Q13: Floating roof seal fastening material shall be austenitic SS.

Q14/Q15: Hot tapping limitation

Q16: Gasket requirements

API Std 620 Design and Construction of Large, Welded, Low-Pressure Storage Tanks, Twelfth Edition Charlie Chong/ Fion Zhang

Q18/Q19: UNKNOWN UNKNOWN MATERIAL MATERIAL YIELD YIELD STRENG STRENGTH TH – OPEN BOOK BOOK

Q20: if you want to use A-283 instead of A-36 require purchaser written approval .

SEE also 4.1.5 Rules for SUBSTITUTION OF PLATE Q21: Routine Routine inspecti inspection on interva intervall – one month month


https://law.resource.org/pub/us/cfr/ibr/002/api.620.2002.pdf

Q22: Personnel for routine inspection

Q23: If the internal inspection is only for tank t ank bottom


Robotic


Q24: Roof’s suitability for service

Q25: Appendix Q25: Appendix M for service service temperature temperature >200⁰F

Q26: Impressed Current & Galvanic systems pro & con.


Q27: Impressed Current & Galvanic systems pro & con.

Q28: Foundation Drip Ring Dimension (key word: 3”)

Q29: Dime Dimens nsio ion n “C” “C” (gre (great ater er of of 3” or 5t) 5t) API653: Figure 9.1—Acceptable 9.1—Acceptable Details for Replacement Replacement of Shell Plate Material


5.4 Bottom Plates 5.4.1 All 5.4.1 All bottom plates shall have a corroded corroded thickness thickness of not less than 6 mm (0.236 in.) [49.8 kg/m2 (9.6 lbf/ft2) (see 4.2.1.2)]. Unless otherwise agreed to by the Purchaser, all rectangular and sketch plates (bottom plates on which the shell rests that have one end rectangular) shall have a nominal width of not less than 1800 mm (72 in.). 5.4.2 Bottom plates of sufficient size shall be ordered so that, when trimmed, at least a 50 mm (2 in.) width will project outside the shell or meet requirements given in 5.1.5.7 d whichever is greater. 5.4.3 Bottom plates shall be welded in accordance with 5.1.5.4 or 5.1.5.5. 5.4.4 Unless otherwise specified on the Data Sheet, Line 12, tank bottoms requiring sloping shall have a minimum slope of 1:120 upwards toward center of the tank.


5.4.5 If specified on the Data Sheet, Line 12, a foundation drip ring shall be provided to prevent ingress of water between the tank bottom and foundation. Unless the Purchaser specifies otherwise, the ring shall meet the following requirements (see Figure 5.5). • Mate Materi rial al sha shallll be be carb carbon on ste steel el,, 3 mm (1/ (1/8 8 in.) in.) min minim imum um thi thick ckne ness ss.. • All All rad radia iall joi joint nts s bet betwe ween en sect sectio ions ns of the the dri drip p rin rings gs,, as as well well as betw betwee een n the the drip ring ring and the annular annular plate or bottom, bottom, shall shall be continuously continuously sealwelded. • The The drip drip rin ring g shal shalll exte extend nd at at leas leastt 75 mm (3 in. in.)) beyo beyond nd the the out outer er peripher periphery y of the foundation foundation ringwall ringwall and then turn turn down (up to 90°) at its outer diameter. • The top and bottom bottom of the the drip drip ring ring,, and and the the top top of of the the tank tank botto bottom m edge edge projection beyond the shell, and a portion of the tank shell shall be coated if specified by the Purchaser.


Figure 5.5—Drip Ring (Suggested Detail)

3 in.min

3in.min 24in.min

3 in.min


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Q30: Painting & Coating Inspector qualification requirements

Q31: Major causes of bad lining (Application & Curing factors)


Q32: CP protection criteris: -850mV w.r.t saturated CSE

Q33: Concentration cell corrosion results in pitting corrosion


Q34: Lining suitable for service temperature (obsolete question?)


Q35: Thin film lining usually for new tank

Q36: LV Holiday testing (keyword: NACE RP0188/ testing voltage 67.5V)


Q37: Number of tank settlement readingreading- Perimeter & even number

Q38: Differential aeration aeration corrosion corrosion due due to hard hard rock rock & dirts point contacts contacts


Q39: Change in service (temperature or specific gravity) and the t he necessity of hydrotesting

Q40: MIC appe appeara arance nce – open open book book

Q41: MPI Equipm Equipment ent calibr calibration ation – open book


Q41: Sulfuric acid percentage -85 and Temp -125 F – 50mil


Q42: Magnetizin Magnetizing g equipme equipment nt calibra calibrationtion- Annually, Annually, lifting lifting powerpower- prior prior to use. use.


Q43: Thickness Thickness is .50” Hole Type Type Sourc Source e side


Q44/Q45: Densitometer calibration accuracy ±0.05 Density H&D

Q46: different plate thicknesses transition with 1:4 for Δt . 1/8 (3mm)


Q47: Tank Door sheet welding

Q48: Hierarchy of document


API653: 12.2 Radiographs 12.2.1 Number and Location of Radiographs (forr doorsh (fo doorsheet eet wel weldin ding?) g?) 12.2.1.6 New and replaced shell plate and door sheet welds shall be radiograp radiographed. hed. All junctions junctions between between repair and existing existing welds shall shall be radiographed. radiographed. If defects are found, 100 % radiography shall be performed on the repaired weld. 12.2.1.6.1 For circular replacement plates, a minimum of one radiograph shall be taken regardless regardless of thickness. When the circular replacement replacement plate is located in a shell plate with thickness exceeding 1 in., the weld shall be fully radiographed. 12.2.1.6.2 For square and rectangular replacement plates, at least one radiograp radiograph h shall be taken taken in a vertical vertical joint, joint, and at least least one in a horizontal joint, and one in each corner. When the square or rectangular replacement plate is located in a shell plate with thickness exceeding exceeding 1 in., the vertical joints shall be fully radiographed.


Q49: acceptance limit for pit & welding at bottom plate critical zone

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. ………………….. 9.10.1.2.1 No welding or weld overlays (on the bottom plate) are permitted within the critical zone z one except for the welding of: widely scattered pits (see 4.3.2.2), pinholes, cracks in the bottom plates, the shell-to-bottom weld, welded-on patch plates, or where the bottom plate welded to the t he shell is being replaced.


Q50: Arc-gouging


Arc Gouged


Arc Gouged


Pipeline Pipeline Repai Repairr Welding Welding-- Arc Gougi Gouging ng


Q51: Laminatio Lamination n check for adding adding reinforce reinforcement ment plate plate

Q52: Proposed Proposed nozzle nozzle location location-- 4 UT points points


Q53: NDE Examiner qualification

Q54: Disqualifications of bottom scanning examiners


Q55: Foundation settlement/ Uplift (tank over pressure)

Q56:

Q57, Q57, Maximum UT inspection interval A , 5 YRS B, 15 YRS C, Half of Remaining Life (R.L) D, Quarter of Remaining Life (R.L)


Q58: Banding & Peaking (New & inservice tank has different acceptance criteria)

Q59: Calcining Calcining of concre concrete te due due to high temperatu temperature re and and calcinat calcinated ed concrete concrete absorb water, swell and break.


Q60: Shielding gas used in welding, workers can become asphyxiated by exposure to modified atmospheres

Q61: Plate of unknown origin tested to A6/ A370


ASTM STM A6 - 14 Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling , bars, general requirements, requirements, plates ASTM ASTM A370 A370 - 15 Standard Test Methods and Definitions for Mechanical Testing of Steel Products


Q62: Tempered bead welding

Q63: Tank bottom soil side corrosion


Q64: Design temperature: LODMT of LA (design used LODMT+15⁰F)


LA: 20⁰F, Mini Minimum mum design design metal metal tem[eratur tem[erature e used 20+15 20+15 = 35⁰F API650: 3.6 design metal temperature The lowest temperature considered in the design, which, unless experience or special local conditions justify another assumption, shall be assumed to be 8 °C (15 °F) above the lowest one-day mean ambient temperature of the locality where the tank is to be installed. Isothermal lines of lowest one-day mean temperature are shown in Figure 4.2. The temperatures are not related to refrigerated-tank temperatures (see 1.1.1).


Colorado (Denver) : -15⁰F, Minimum design metal used -15+15 = 0⁰F API650: 3.6 design metal temperature The lowest temperature considered in the design, which, unless experience or special local conditions justify another assumption, shall be assumed to be 8 °C (15 °F) above the lowest one-day mean ambient temperature of the locality where the tank is to be installed. Isothermal lines of lowest one-day mean temperature are shown in Figure 4.2. The temperatures are not related to refrigerated-tank temperatures (see 1.1.1).


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Q65: In-service bottom plate minimum thickness.

Q66: Internal inspection interval


Q67: Internal inspection interval

Q68: Maximum initial internal inspection interval

Q69: 10+5+2 =17


Q70: J value – open book t =.5”, toughness toughness does does not meet meet API650 7th Ed. Answer: J = 3” 9.9 Alteration of Existing Shell Penetrations 9.9.1 Existing shell penetrations may be altered if the altered details comply with the requirements of API 650, Section 5.7 including the requirements for minimum reinforcing area and the requirements for spacing of welds around connections. 9.9.4 A 9.9.4 A new bottom may be installed through an existing existing tombstone reinforcing plate, provided all weld spacing and reinforcement requirements, as specified in API 650, are met. One of the following methods shall be used. a) Remove only that portion of the existing reinforcing plate necessary to weld and test the new bottom-to-shell weld. The lower edge of the reinforcing plate shall be cut reasonably straight and horizontal and beveled to facilitate welding. See Figure 9.10 for weld joint details.


Figure 9.10—Details for Installing a New Bottom Through an Existing Tombstone Reinforcing Plate


b) Bevel Bevel the shell shell from the inside inside to allow allow for a full full penetratio penetration n weld betwee between n the bottom and shell. This method method shall only be be used on on tanks where the annular plate plate or bottom bottom sketch sketch plate thickness thickness is equal to or greater than 10 mm (3/8 (3/8 in.). This This weld detail detail shall shall be used along along the full width width of the reinforcing plate plate and shall extend extend a minimum of 25 mm (1 in.) beyond beyond the edges of the reinforcing reinforcing plate. Once beyond beyond the reinforcing reinforcing plate, the full penetration weld shall tie in to the outside shell-to-bottom fillet weld to creat create e a “water “water stop stop”” and then then transi transitio tion n to the typic typical al shell shell-to -to-bo -botto ttom m weld weld detail. detail. See Figure Figure 9.11 for for weld weld joint joint details. details.




c) The bottom bottom portio portion n of the the rein reinfor forcin cing g plate plate may may be be remo removed ved using using a horizonta horizontall cut between between the the bottom bottom invert invert of the nozzle nozzle neck neck and and the new bottom per requirements requirements of Figure Figure 9.12. The removed (or new) new) reinforcing reinforcing plate shall shall be prepared prepared for a full fusion fusion splice weld with telltale telltale hole added added (see Figure Figure 9.12). 9.12). The The remove removed d (or (or new) reinforci reinforcing ng plate plate shall shall be reinstalled after the shell-to-bottom shell-to-bottom weld has been completed, inspected, and tested. tested. The splice splice weld shall be made made prior prior to the reinforci reinforcing ng plate plate weld to bottom bottom plate weld. The completed completed splice splice weld weld shall shall be magnet magnetic ic particle examined.





Q71: Minimum RT diagnostic length

Q72: “R” for identi identifying fying repair repair weld weld for RT

Q73/74/75: Defini Definitio tion n of major major altera alteratio tion n Major Major altera alteratio tion n – A -12” -12” , B- 18”


API653: 3.20 major alteration/or alteration/or major repair An alteration or repair repair that includes any of the following: a) instal installing ling a shell shell penetr penetrati ation on larger than NPS 12 beneath the design liquid li quid level; b) installing installing a bottom bottom penetr penetration ation within 12 in. in. of the the shell; shell; c) removi removing ng and repl replaci acing ng or adding adding a shel shelll plate plate benea beneath th the the design design liqu liquid id level level wher where e the long longest est dime dimensi nsion on of of the repla replacem cement ent plat plate e excee exceeds ds 12 in.; in.; d) removi removing ng or replac replacing ing annul annular ar plate plate ring ring mater material ial wher where e the longe longest st dimens dimension ion of of the replac replaceme ement nt plate plate exce exceeds eds 12 in.; in.; e) complete complete or partial partial (more (more than one-half one-half of the the weld weld thickness thickness)) remov removal al and and replacem replacement ent of of more more than than 12 in. in. Of vertical vertical weld weld joining joining shell plates plates or radial weld joining the annular plate ring; f) ins install tallin ing g a new new bott botto om; NOTE Installation Installation of a portion of a new bottom as described in 12.3.3.3 is not defined as a major repair. g) removi removing ng and and replac replacing ing par partt of the weld weld attac attachin hing g the shell shell to the the botto bottom, m, or to the the annular annular plate ring, in excess excess of of the amounts amounts listed listed in 12.3.2. 12.3.2.5.1 5.1 a); a); h) jacking a tan tank shell.


Key word: Greater than 12”


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Q76: Fill height as determined by actual thickness

Q77:

Q78:

Q79:


API653: 4.3.2 Actual Thickness Determination 4.3.2.1 e) The criteria for continued operation is as follows: I. the value t1 shall be greater than or equal to tmin (see 4.3.3 or 4.3.4), subject subject to verification verification of all other other loadings loadings listed listed in 4.3.3.5; II. the value t2 shall be greater than or equal to 60 % of tmin; and III. any corrosion corrosion allowance allowance required required for service service until the time time of the the next next inspection shall be added to tmin and and 60 % of tmin. 4.3.2.2 Widely scattered pits may be ignored provided that: a) no pit pit dep depth th res resul ults ts in in the the rema remain inin ing g shel shelll thic thickn knes ess s bein being g less less than than one one-half the minimum minimum acceptable acceptable tank tank shell thickness thickness exclusive exclusive of the corrosion allowance; and b) the sum of thei theirr dimen dimensio sions ns alon along g any any verti vertical cal line line does does not not exce exceed ed 2 in. in an 8-in. length (see Figure 4.2).


Discussion shell plate thickness:  t1 = average thickness The average plate thickness as determine using L=3.7√(Dt2) shall be ≥tmin 

t2 = the minimum thickness The minimum or least thickness as determined when inspection a corroded area. The t2 shall be ≥0.6tmin

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tmin = the design minimum shell thickness The tmin = 2.6(H-1)DG/SE for whole course thickness calculation

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Pitmaximum = the pitting on a shell plate shall not result in the thickness <0.5tmin excluding corrosion allowance.


Q80: φ ray density ≥2.0 H&D X ray ≥1.8 H&D

Q81: Ligh Lighte terr “B” reje reject ct


9.8.4 Radioactive Source Selection For weld inspection, typically radioactive isotopes of Iridium 192 or Cobalt Cobalt 60 are used. used. X-ray machin machines es may also also be used. 

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Iridium 192 is normally normally used for for performing performing radiography radiography on steel with a thic thickn knes ess s rang range e of 0.2 0.25 5 in. in. – 3.0 3.0 in. in. (6.3 (6.3 mm mm – 76.2 76.2 mm) mm).. Cobalt Cobalt 60 60 is used used for steel steel thick thicknes ness s of 1.5 in. in. – 7.0 in. (38 (38 mm mm – 178 mm). mm).

The minimum minimum or maximum maximum thickness that that can be radiographed radiographed for a given material material is determin determined ed by demons demonstrati trating ng that that the require required d sensitivit sensitivity y has been been obtained.


9.8.4 Radioactive Source Selection For weld inspection, typically radioactive isotopes of Iridium 192 or Cobalt Cobalt 60 are used. used. X-ray machin machines es may also also be used. 

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Iridium 192 is normally normally used for for performing performing radiography radiography on steel with a thic thickn knes ess s ran range ge of ¼ in. in. – 3.0 3.0 in. in. (6.3 (6.3 mm – 76.2 76.2 mm). mm). Coba Cobalt lt 60 60 is used used for for ste steel el thi thick ckne ness ss of of 1½ in. in. – 7.0 7.0 in. in. (38 (38 mm – 178 178 mm). mm).

The minimum minimum or maximum maximum thickness that that can be radiographed radiographed for a given material material is determin determined ed by demons demonstrati trating ng that that the require required d sensitivit sensitivity y has been been obtained.


Q82: VT

Q83: Primary reason for PWHT


Q84: Filling Rates for thickness thickness (.5”) (.5”)

Q85: W.P.S question joint sketch given but did not mention mention the grove angle. Q86: P.Q.R questi question on – thickness thickness range range qualific qualification ation .


Q87: P.Q.R question question - SA 516 516 Gr Gr 70 – Mechanic Mechanical al and and bend bend test results results Q88: Critical length calculation – Given tank dia, least thickness , average average thickness thickness,, remaining remaining thickness thickness and ask us calculate critical critical length. length. Q89: T minimum for bottom shell Q90: Remaining life calculation Q91: Given corrosion corrosion rates rates for shell shell and bottom bottom plates . ask us tell Maximum UT inspec inspectio tion n inter interval val . Q92: Given different data for calculation height (H).


QW-150 TENSION TESTS QW-153 QW-153 Acceptan Acceptance ce Criteria Criteria — Tension Tension Tests Tests QW-153.1 Tensile Strength. Minimum values for procedure qualification are provided under the column heading heading “Minimum Specified Specified Tensile, ksi” of table QW/QB-422. In order order to pass the tension test, the specimen shall have a tensile tensile strength that that is not less than (a) the minimum minimum specifi specified ed tensile tensile strength strength of the the base metal; metal; or (b) the minimum minimum specifie specified d tensile tensile strength strength of the weaker weaker of the two, two, if base metals of of different different minimum tensile strengths are used; or (c) the minimum minimum specified specified tensile tensile strengt strength h of the weld metal metal when when the applicabl applicable e Section Section provides for the use of weld metal having lower room temperature strength than the base metal; (d) if the specimen specimen breaks breaks in the base metal metal outside outside of the weld weld or weld weld interface, interface, the test test shall be accepted as meeting the requirements, provided the strength is not more than 5% below the minimum specified tensile strength of the base metal. (e) the specified specified minimum minimum tensile strength strength is for full thickness thickness specimens specimens including including cladding cladding for Aluminum Al clad materials (P-No. (P-No. 21 through P-No. 23) less than 1 ⁄ 2 in. (13 mm). For Aluminum Al clad materials 1 ⁄ 2 in. (13 mm) and greater, the specified minimum tensile strength is for both full thickness specimens that include cladding and specimens taken from the core.


QW-160 GUIDED-BEND TESTS QW-163 QW-163 Accepta Acceptance nce Criteri Criteria a — Bend Tests Tests The weld and heat-affected zone of a transverse weld bend specimen shall be completely within the bent portion of the specimen after testing. The guided-bend specimens shall have no open discontinuity in the weld or heatffecte ffected d zone zone excee exceedin ding g 1 ⁄ 8 in. (3 mm), measured in any direction on the convex surface of the specimen after bending. Open discontinuities occurring on the corners of the specimen during testing shall not be considered unless there is definite evidence evidence that they result from lack of fusion, slag inclusions, inclusions, or other internal discontinuities. For corrosion-resistant corrosion-resistant weldoverlay cladding, no open discontinuity exceeding 1 ⁄ 16 16 in. (1.5 mm), measured in any direction, shall be permitted in the cladding, and no open discontinuity exceeding 1 ⁄ 8 in. (3 mm) shall be permitted along the approximate weld interface.


QW-170 NOTCH-TOUGHNESS TESTS QW-171.2 Acceptance. The acceptance criteria shall be in accordance with that Section specifying impact requirements. requirements. QW-190 OTHER TESTS AND EXAMINATIONS QW-191 Volumetric NDE QW-191.1 Radiographic Examination QW-191.1.2 Acceptance Criteria QW-191.2 Ultrasonic Examination QW-191.2.3 Acceptance Criteria for Qualification Test Welds.


Q92: Welder symbol is not required for which type of joints? CHAPTER CHAPTER 11 API 653 653 … easy … see questi question on and and refere reference nce below Q93: Given shell and bottom plate corrosion rate and ask find UT inspection interval interval Since we know know corrosion corrosion rate, rate, calculate calculate the corros corrosion ion rate rate RCA/2N RCA/2N , if not known the interval is 5 years b) When the corrosion rate is known, the maximum interval shall be the smaller of RCA/2N years (where RCA is the difference between the measured shell thickness and the minimum required thickness in mils, and N is the shell corrosion rate in mils per year) or 15 years. Q94: Meaning of RCA


Q95: Keyword in the exam is experiences with coatings and linings – OPEN BOOK


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Q96: Key word word is to the maximum maximum liquid liquid level level , not shell height height – in the examinatio examination n they mentioned mentioned tank height height and liquid level and ask ask us which one we have have to consider consider for for calculating calculating thickne thickness ss


Q97: Earthing ≤ 25Ω approximately

Q98: Internal corrosion of tank vapor space by (1) H2S (2) H2O (3) O2 (4) any combination of above.


Q98B: Carbon Carbon Steel Steel (Unknow (Unknown n Specific Specification ation)) – thickness thickness is .5” .5” and temp 20 F- safe for us use ⁰


Q99: Need for Hydrotest .


Q100: New material

Q101: Thickness calculation and material allowable stress


Q102: The AI designate inspection hold point

Q103: Minimum dimension of replacement replacement shell plate is 12” or 12t which which ever is greater.


API653: 9.1.3 All 9.1.3 All repair work must must be authorized by the authorized authorized inspector or an engineer engineer experienced experienced in storage storage tank design, before commencement commencement of the work by a repair repair organi organizatio zation. n. Authorization for alterations alterations to storage tanks that comply with API 650 may not be be given given without without prior prior consu consultatio ltation n with, with, and approved approved by, an an engineer engineer experienced in storage tank design. The authorized inspector will designate inspection inspection hold points required required during during the repair or or alteration sequence and minimum minimum documentation documentation to be submitted submitted upon job completion completion.. The authorized authorized inspector inspector may give give prior prior genera generall authorizat authorization ion for for limited limited or or routin routine e repair repairs s as long long as the the author authorize ized d inspec inspector tor is sure sure that that the the repair repairs s will not require require hydrostatic hydrostatic testing or do not require an engineering evaluation.


9.2.2 Minimum Dimensions of Replacement Shell Plate 9.2.2.1 The minimum minimum dimension dimension for a replacement shell plate is 12 in. or 12 times the thickness of the replacement replacement plate, whichever whichever is greater. 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 See Figure 9.1 for typical typical details of acceptable replacement replacement shell plates.


Q104:

Q105:

Q106:


API650: 5.6 Shell Design 5.6.1 General 5.6.1.2 Unless otherwise agreed to by the Purchaser, the shell plates shall have a minimum minimum nominal nominal width of 1800 1800 mm (72 (72 in.). Plates that are are to be buttwelded shall be properly squared. API653: 9.2 Removal and Replacement of Shell Plate Material 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 replacement plate, whichever whichever is greater. The replacement plate may be circular, oblong, square with rounded corners, or rectangular with rounded corners except except when an entire shell plate is replaced. See Figure 9.1 for typical details of acceptable replacement replacement shell plates.


API653 9.3 Shell Repairs Using Lap-welded Patch Plates 9.3.1.7 The maximum vertical and horizontal dimension of the repair plate is 48 in. and 72 in., respectively. The minimum repair plate dimension is 4 in. The repair plate shall be formed to the shell radius.


Discussion Type of repair plate 1. New plate Minimum Minimum dimensio dimension: n: 72” width 2. Repl Replac acem emen entt pla plate Minimum Minimum dimensio dimension n 12” or 12t whichever whichever greater greater 3. Patc Patch h wel weld ded plat plate e Maximum Maximum dimension dimension 48” vertical vertical x 72” 72” horizontal, horizontal, minimum minimum 4”.


Tsingdao Beer


Q&A Practice 2 API 653 PREPARATORY PREPARATORY IMPORTANT CLOSED BOOK QUESTIONS



My Self Study Notes QQ 自学群: API 超级检验师 47610017

API 653 PREPARATORY PREPARATORY IMPORTANT CLOSED BOOK QUESTIONS A PI 653 Third hird / Fifth Fifth Edition

No. No . 1

Q UES UESTION Defini De finiti tio o n o f the C ritic itica a l zo ne

C O DE

C LAUSE LAUSE

A PI653 PI653

3.7 3.7

3.10 criti cal zone 3.10 The portion of the tank bottom or annular plate within 3 in. of the inside edge of the shell, measured radially inward.

2

Definiti Definitio o n o f C hange ha nge o f Servi ervic e

A PI653 PI653

3.9

3.7 change in service A change from previous operating conditions involving involving different properties properties of the stored product such as specific specific gravity or corrosivity corrosivity and/or different service conditions of temperature and/or pressure.

3.

M inimum inimum thicknes thic kness s o f c o rro d e d ro o f p late

A PI653 PI653

4.2.1 4.2.1.2 .2

4.2.1.2 Roof plates corroded to an average thickness of less than 0.09 in. in any 100 in.2 area or roof plates with any holes through the roof plate shall be repaired or replaced.

4.

Limits Limits o f L L = 3.7√(Dt2), but not more than 40 in.

A PI653

4.3.2.1

5.

Defini De finiti tio o n o f wide wid e ly sc a ttere ttere d p its its

A PI653 PI653

4.3.2 4.3.2.2 .2

4.3.2.2 Widely scattered pits may be ignored provided that: a) no pit depth results in the remaining shell shell thickness being less less than one-half the minimum minimum acceptable tank shell thickness exclusive 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. 8-in. length (see Figure Figure 4.2).

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My Self Study Notes QQ 自学群: API 超级检验师 47610017 6.

C a use use s for fo r shell he ll d isto istorrtion A PI653 PI653 4.3.5.2 4.3.5.2 4.3.5 Distortions 4.3.5.1 Shell distortions include out-of-roundness, buckled areas, flat spots, and peaking and banding at welded joints. 4.3.5.2 Shell distortions can be caused by many conditions such as foundation settlement, over or under pressuring, high wind, poor shell fabrication, or repair techniques, and so forth. 4.3.5.3 Shell distortions shall be evaluated on an individual basis to determine if specific conditions are considered acceptable for continuing tank service and/or the extent of corrective action.

7.

C ra c ks in the shal ha ll to b o tto tto m wel we ld – wha t should b e d o ne A PI65 PI653 4.3 4.3.6 4.3.6 4.3. 6 Flaws Flaws such as cracks or laminations shall be thoroughly examined and evaluated to determine their nature and extent and need for repair. If a repair is needed, a repair procedure shall be developed and implemented. The requirement for repairing scars such as arc strikes, gouges, or tears from temporary attachment welds must be evaluated on a case-by-case basis. Cracks in the shell-to-bottom weld shall be removed. Comments: Crack- No, No Others- must be evaluated on a case by case basis

8.

What Wha t is the rea so n for the d istort istortion ion o f a nchor nc hor b o lts lts & excess exc essiv ive e c ra c king king o f API653 4.5.3 c o ncr nc rete struc tructur tures es 4.5. 4. 5.3 3 Anchor Bolts Distortion of anchor bolts and excessive cracking of the concrete structures in which they are embedded may be indications of either serious foundation settlement or a tank overpressure uplift condition.



10. 10.

11. 11.

12. 12.

Ta nks fab fa b rica ic a ted fro fro m steels tee ls o f unknown unknow n toug hnes hne ss, thicknes thic kness s less less than tha n ½” c a n API653 5.3.7 b e ope o perra ted a t above ab ove what wha t mi minimum nimum shell metal tempe temperra tur ture 5.3.5 Step 4—If a tank shell thickness is no greater than 0.5 in., the risk of failure due to brittle fracture is minimal, provided that an evaluation for suitability of service in accordance with Section 4 has been performed. The original nominal thickness for the thickest tank shell plate shall be used for this assessment. 5.3.6 Step 5—No known tank failures due to brittle fracture have occurred at shell metal temperatures of 60 °F or above. Similar assurance against brittle fracture can be gained by increasing the metal temperature by heating the tank contents. 5.3.7 Step 6—Industry experience and laboratory tests have shown that a membrane stress in tank shell plates of at least 7 ksi is required to cause failure due to brittle fracture. Inter Interval va l for fo r ro utine In-se In-service vic e insp insp ec tion A PI653 PI653 6.3.1.2 6.3.1.2 6.3.1 Routine In-service Inspections 6.3.1.1 The external condition of the tank shall be monitored by close visual inspection from the ground on a routine basis. This inspection may be done by owner/operator personnel, and can be done by other than authorized inspectors as defined in 3.4. Personnel performing this inspection should be knowledgeable of the storage facility operations, the tank, and the characteristics of the product stored. 6.3.1.2 The interval of such inspections shall be consistent with conditions at the particular site, but shall not exceed one month. Who shall ha ll c a rry o ut Externa Externall Insp Insp e c tion A PI653 PI653 6.3.2.1 6.3.2.1 6.3.2 External Inspection 6.3.2.1 All 6.3.2.1 All tanks shall be given a visual visual external external inspection inspection by by an authorized authorized inspector. inspector. This This inspection inspection shall shall be called called the external inspection and must be conducted at least every five years or RCA/4 N years (where RCA is the difference between the measured shell thickness and the minimum required thickness in mils, and N is the shell corrosion rate in mils per year) whichever is less. Tanks may be in operation during this inspection. Inter Interval va l for fo r Externa Externall insp insp e c tion A PI653 PI653 6.3.2.1 6.3.2.1 As abo above ve


My Self Study Notes QQ 自学群: API 超级检验师 47610017 4.4.1 General 4.4.1 Tank bottom inspection strategies shall provide suitable data which, when used with the procedures in this standard, will determine the tank bottom integrity necessary to prevent leakage of fluids that may cause environmental damage. Each aspect of corrosion phenomena, and other potential leak or failure mechanism must be examined. Periodic assessment of tank bottom integrity shall be performed in addition to the internal inspections specified in 6.4. The assessment period shall be less than or equal to the appropriate internal inspection interval given in 6.4.2. The use of leak detection tests or monitoring systems (such as double bottoms or liners under tank bottoms with leak detection pipes) will satisfy the requirement for periodic assessment between internal inspections. Excessive foundation settlement of storage tanks can affect the integrity of tank shells and bottoms. Therefore, monitoring the settlement behavior of tanks is a recognized practice to assess the integrity of tank bottoms. See Annex B for techniques techniques for evaluati evaluating ng tank bottom bottom settlement. settlement.

17. 17.

a lte lte rnati na tive ve Internal Insp Insp ec tio tio n method metho d A PI653 PI653 6.4.3 6.4.3 6.4.2.1.2 As 6.4.2.1.2 As an alternative alternative to establishing establishing the the initial interval interval in accordan accordance ce with Section 6.4.2.1 6.4.2.1 and and Table 6.1, 6.1, the initial internal inspection date and reassessment can be established using Risk Based Inspection (RBI) assessment per 6.4.2.2.2. These assessments may establish an initial inspection interval exceeding 10 years but shall not exceed 20 years for tanks without a Release Prevention Barrier, or 30 years for tanks with a Release Prevention Barrier except as follows.

18. 18.

What Wha t is the b o ttom p late minimum minimum thic thic kness

A PI653 PI653

Ta b le 6-1 a) 0.10” Tank bottom/foundation design with no means for detection and containment of a bottom leak. b) 0.05” Tank bottom/foundation design with means to provide detection and containment of a bottom leak. c) 0.05” Applied tank bottom reinforced lining, > 0.05 in. thick, in accordance accordance with API 652.


My Self Study Notes QQ 自学群: API 超级检验师 47610017 19. 19.

C o nstr nstruc uc tio tio n re c o rd s shall ha ll include inc lude the foll fo llo o wing information A PI653 PI653 6.8. 6.8.2 2 6.8. 6. 8.2 2 Construct ion Re Records cords Construction records may include nameplate information, drawings, specifications, construction completion report, and any results of material tests and analyses.

20. 20.

New Ne w mater ma teriia l for tank rec o nstr nstruc ucti tio o n shall ha ll c o mply to which whic h stand a rd A PI65 PI653 7.2 7.2 7.2 New Materials All new materials materials used used for repair, repair, alterations, alterations, or reconstr reconstruction uction shall shall conform conform to the current current applicable applicable standard. standard.

21. 21.

Welding c o nsuma nsumab b les shal ha ll c o nform to which whic h sp ec ifica ifica tio tio n

A PI65 PI653

7.4

7.4 Weldin 7.4 Weldin g Consumables Welding consumables shall conform to the AWS classification that is applicable to the intended use. 22. 22.

What Wha t a re the minimum minimum d imen imens sions for fo r a re p lac e ment shell he ll A PI653 PI653 9.2. 9.2.2.1 2.1 9.2.2 9.2 .2 Minim um Dimension Dimens ions s 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.

23. 23.

The c o rners o f a re p a ir p late shall ha ll b e ro unded und ed to wha t minimum minimum ra d ius A PI653 PI653 9.3.1 9.3.1.4 .4 9.3.1.4 The shape of the repair plate may be circular, oblong, square, or rectangular. All corners, except at the shell to bottom joint, shall be rounded to a minimum radius of 2 in. The nozzle reinforcing plate shapes of API 650, Figure 5-8, are also acceptable.



Insert Insert p late having ha ving higher highe r thic thic kness than tha n the shall ha ll p late shall ha ll b e tap ta p ered to A PI653 PI653 9.8.2 9.8.2(c (c)) 9.8.4 The following erection requirements shall be met: a) if an integral reinforcement design is used, the insert plate at its periphery shall have a 1:4 reduction taper to match the shell plate thickness when the insert plate exceeds the shell plate thickness by more than 1/8 in. (3mm) ; Comments: Taper if Δt >3mm

25. 25.

M inimum inimum thk. o f new ne w ro o f to b e use use d for fo r re p a ir for fo r a fixed fixed ro o f shall ha ll b e A PI653 PI653 9.11 9.11.1 .1.1 .1 9.11.3 Self-supporting Roofs 9.11.3.1 The nominal thickness of new roof plate shall be 3/16 in. (4.7mm) or the required plate thickness given in API 650, Section 5.10.5 5.10.5 or Section 5.10.6, plus plus any specified specified corrosion corrosion allowan allowance, ce, whichever whichever is greater. greater. 9.11.3.2 The details of the roof-to-shell junction shall meet the requirements of API 650, Section 5.10.5, Section 5.10.6, or Annex F of this standard, as applicable, for the intended service.

26. 26.

The minim minimum um height o f tank ta nk liquid a b o ve hot ho t tap loc a tio tio n shall ha ll b e a t lea st A PI65 PI653 9.1 9.14.1.2 .1.2 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.

27

Duri During hot ho t tap p ing o p eration welding we lding will will b e d o ne usi using which whic h elec tro tro d es 9.14.1.3 Welding shall be done with low hydrogen electrodes.

28. 28.

A re hot ho t tap ta p s p ermitted ermitted o n the ro o f o f a tank ta nk A PI653 PI653 9.14.1.4 Hot taps are not permitted on the roof of a tank or within the gas/vapor space of the tank.


A PI653 PI653

9.14. .14.2. 2.3 3

9.14 9.14.2 .2.4 .4


30. 30.

31. 31.

The max ma ximum a llo llo wed we d u und nderc ercutt uttiing for hor ho rizo ntal joints joints of o f a rec rec o nstr nstruc ucted ted API653 10.4.2.5 tank ta nk is API653: 10.4.2.5 The edges of all welds shall merge with the surface of the plate without a sharp angle. Maximum permissible weld undercut shall be in accordance with API 650, Section 7.2.1.4 and Section 8.5.1 b). API650: 8.5.2 A 8.5.2 A weld shall be acceptabl acceptable e by visual visual examination examination if the inspecti inspection on shows shows the following. following. a) There are no crater cracks, other surface cracks or arc strikes in or adjacent to the welded joints. b) Maximum permissible undercut is 0.4 mm (1/64 in.) in depth for vertical butt joints, vertically oriented permanent attachments, attachment welds for nozzles, manholes, flush-type openings, and the inside shell-to-bottom welds. For horizontal butt joints, horizontally oriented permanent attachments, and annular-ring butt joints, the maximum permissible undercut is 0.8 mm (1/32 in.) in depth. c) If the materi ma teria a l sp ec ific ific a tio tio n for fo r the stee steell fro fro m a n exis existing ting tank tan k is unknown unkno wn or API653 11.1.2 o bsolete, bsolete, how do you qua lify the welding proc proc edur ed ure e 11.1.2 Weldability of steel from existing tanks shall be verified. If the material specification for the steel from an existing tank is unknown or obsolete, test coupons for the welding procedure qualification shall be taken from the actual plate to be used.

A t wha t interva intervals ls Welde Weld e rs identi ide ntific fica a tio tio n shall ha ll b e mar ma rked a d j. to welds we lds A PI653 PI653 11.2 11.2.2 .2 11.2.2 The welder or welding operator’s identification mark shall be hand- or machine-stamped adjacent to and at intervals not exceeding 3 ft along the completed welds. In lieu of stamping, a record may be kept that identifies the welder or welding operator employed for each welded joint; these records shall be accessible to the inspector. Roof plate welds and flange-to-nozzle-neck welds do not require welder identification.



What Wha t a lternativ lternative e method metho d s a re used used to ins insp ec t the integ integrrity ity o f the welded we lded API653 12.1.7.1 bottom joint API653: 12.1.7 Bo tt om oms s 12.1.7.1 Upon completion of welding on a tank bottom, the plates and the entire length of new welds for tank bottom plates shall be examined visually for any potential defects and leaks. Particular attention shall apply to areas such as sumps, dents, gouges, three-plate laps, bottom plate breakdowns, arc strikes, temporary attachment removal areas, and welding lead arc burns. Visual examination acceptance and repair criteria are specified in API 650, Section 8.5. In addition, all new welds, including the weld attaching a patch plate to the bottom, the areas of bottom plate restored by welding, and the restoration of welds found with defects during an internal inspection shall be examined by one of the methods specified in API 650, Section 7.3.3. Leaking areas shall be repaired by grinding and rewelding as required, and the repaired area shall be retested. API650: 7.3.3 Examin Exam in ati on and Test Testin in g of o f t he Tank Bo Bott tt om Upon completion of welding of the tank bottom, the bottom welds and plates shall be examined visually for any potential defects and leaks. Particular attention shall apply to areas such as sumps, dents, gouges, three-plate laps, bottom plate breakdowns, arc strikes, temporary attachment removal areas, and welding lead arc burns. Visual examination acceptance and repair criteria are specified in 8.5. In addition, all welds shall be tested by one of the following methods. a) A vacuum-box test in accordance with 8.6. b) A tracer gas test in accordance with 8.6.11. c) After at least the lowest shell course has been attached to the bottom, water (to be supplied by the Purchaser) shall be pumped underneath the bottom. A head of 150 mm (6 in.) of liquid shall be maintained using a temporary dam to hold that depth around the edge of the bottom. The line containing water for testing may be installed temporarily by running it through a manhole to one or more temporary flange connections in the bottom of the tank, or the line may be installed permanently in the subgrade beneath the tank. The method of installation should be governed by the nature of the subgrade. Reasonable care shall be taken to preserve the prepared subgrade under the tank.



A rea s of bott bo ttom om pla pla te repa ep a ired by b y welding in in a d dition dition to to MT/ MT/ PT a re any other API653 12.1.7.3 testing done. 12.1.7.3 In addition to the requirements in 12.1.7.1, areas of bottom plate repaired by welding shall be examined by the magnetic particle method or the liquid penetrant method. In addition, the repaired area shall also be tested using a vacuum box and solution or a tracer gas and detector.

34. 34.

The minimum minimum d iagno iag nos stic tic length leng th o f e a c h ra d iogr iog ra p h is 12.2.1.7 The minimum diagnostic length of each radiograph shall be 6 in.

35. 35.

For p e netr ne tra a tio tio n insta install lled ed using using insert insert p lates la tes , b utt weld we ld b etwe etw e en the the ins insert ert API653 12.2.1.8 p la te & shell shell plate pla te sha shalll be ra diogr diog ra phed phe d to wha t extent extent 12.2.1.8 For penetrations installed using insert plates as described in 9.8.6, the completed butt welds between the insert plate and the shell plate shall be fully radiographed.

36. 36.

Hyd Hyd ro stati ta tic c test test o f a re c o nstr nstruc uc ted tank ta nk shall ha ll b e held he ld for fo r how ho w long time time.. A PI653 PI653 12.3 12.3.1. .1.1 1 12.3.1 When Hydrostatic Testing is Required A full hydrostatic hydrostatic test, test, held for for 24 hours, hours, shall be performed performed on the following following.. a) A reconstructed tank. b) Any tank that has undergone major repairs or major alterations (see Section 3) unless exempted by 12.3.2 for the applicable combination of materials, design, and construction features. c) A tank where an engineering evaluation indicates the need for the hydrostatic test due to an increase in the severity of service. Examples of increased service severity are an increase in operating pressure (such as storing a product with a higher specific gravity), lowering the service temperature (see Figure 5.2), and using tanks that have been damaged.


A PI653 PI653

12.2 12.2.1. .1.7 7


A t wha t interva intervals ls shall ha ll se ttle ttle ment b e mea sure ure d d uring uring hydr hyd ro test test A PI653 PI653 12.5 12.5.2 .2 12.5.3 Settlement Survey During Hydrostatic Testing When a settlement survey is required in accordance with 12.5.1, tank settlement shall be measured during filling and when the test water reaches 100 % of the test level.

38. 38.

The max ma ximum sp a c ing a c ro ss d iameter iame ter o ver which whic h mea sureme urements nts o f b o tto tto m settlement are taken is Figure B.2—Measurements of Bottom Settlement (Internal) Tank Out-of-service NOTE See 12.5.1.2 for method of determining the number of measurement points.


A PI653

Fig Fig . B-2

My Self Study Notes QQ 自学群: API 超级检验师 47610017 12.5. 12. 5.1 1 When Settl Settl ement Surv ey is Re Requi qui red A settlement settlement survey shall be conducte conducted d for all existing tanks that undergo a hydrostatic hydrostatic test, test, except for for tanks that that have a documented service history of acceptable settlement values, and no settlement is anticipated to occur during the hydrotest. 12.5.2 12.5. 2 Initi al Settlement Survey When a settlement survey is required in accordance with 12.5.1, the tank settlement shall initially be surveyed with the tank empty, using an even number of elevation measurement points, N , uniformly distributed around the circumference. An initial settlement survey, prior to the first hydrostatic test, provides baseline readings for future settlement evaluation. In the absence of this initial survey, the tank shall be assumed to be initially level. The minimum number of elevation points shall be as indicated by the following equation: N = D/ 10 10

where is the tank diameter, in feet (ft). N is the minimum required number of settlement measurement points, but no less than eight. All values of N shall be rounded to the next higher even whole number. The maximum spacing between settlement measurement points shall be 32 ft. D

39. 39.

Inter Internal na l Bo ttom ttom se ttle ttle ment ment for fo rmula A PI653 PI653 B-3-3 B.3.3 B.3 .3 Internal Internal Bott om Settlements or Bulges Measure the bulge or depression. The permissible bulge or depression is given by the following equation (see Note). BB = 0.37R where BB is maximum height of bulge or depth of local depression, in inches; R is radius of inscribed circle in bulged area or local depression, in feet.



What Wha t is the NDT Insp Insp e c tor Q uali ua lific fica a tio tio n re q uire uire ment for fo r c a rrying ying out UT d uring uring A PI653 F 4.3 tank repair? API650: U.4 Pers on onnel nel Qual Qualif if ic icati ati on ons s and an d Train Tr ainin ing g U.4.1 Person Pers onnel nel Qual Qualif if ic ati ation ons s —Personnel performing and evaluating UT examinations shall be qualified and certified in accordance with their employer’s written practice. ASNT SNT-TC-IA or CP-189 shall be used as a guideline. Only Level-II or Level-III personnel shall perform UT examinations, analyze the data, or interpret the results.

41

UT p ro c ed ure ure shall ha ll follo follo w which whic h C o d e/ Stand a rd An nex T (informative) ND Annex NDE E Requir Requirements ements Summ ary

A PI65 PI653

F 4.4

Definitions:  MT =Magnetic Particle Examination  Pen Oil =Penetrating Oil Test  PT =Liquid Penetrant Examination  RT=Radiographic Testing VB =Vacuum-Box Testing   VE =Visual Examination Accep Ac ceptan tance ce Stand St andard ards: s:  MT: ASME Section VIII, Appendix 6 (Paragraphs 6-3, 6-4, 6-5)  PT: ASME Section VIII, Appendix 8, (Paragraphs 8-3, 8-4, 8-5) RT: ASME Section VIII, Paragraph UW-51(b)   Tracer Gas: API Std 650, Section 8.6.11.b  UT: For welds examined by UT in lieu of RT, acceptance standards are in Annex U.6.6. For UT when RT is used for the requirements of 7.3.2.1, the acceptance standard is as agreed upon by the Manufacturer and Purchaser. VB: API Std 650, Section 8.6.9   VE: API Std 650, Section 8.5.2


My Self Study Notes QQ 自学群: API 超级检验师 47610017 Examiner Qualifications: Examiner  MT:API Std 650, Section 8.2.3 PT:API Std 650, Section 8.4.3  RT:ASNT SNT-TC-1A Level II or III. Level-I personnel may be used under the supervision of a Level II or Level III  with a written procedure in accordance with ASME Section V, Article 2.  Tracer Gas: None UT:For welds examined by UT in lieu of RT, the inspector must be ASNT-TC-1A or CP-189 Level II or Level III  per  API Std 650 650 Annex Annex U.4.1. For For UT when when RT is used for for the requirements requirements of 7.3.2.1, 7.3.2.1, the required required qualificatio qualifications ns are ASNT-TC-1A ASNT-T C-1A Level Level II or Level Level III. A Level I may be used used with restrictions, restrictions, see API API Std 650, 650, Section 8.3.2.   VE: API Std 650, Section 8.5.1  VB: API Std 650, Section 8.6.4 Procedure Requirements:  MT: ASME Section V, Article 7 PT: ASME Section V, Article 6   RT: A procedure is not required. However, the examination method must comply with ASME Section V, Article 2.  Acceptance Acceptan ce standards standards shall shall be in accordanc accordance e with ASME ASME Section Section VIII, Paragraph Paragraph UW-51(b UW-51(b). ).  UT: For shell welds examined by UT in lieu of RT, ASME, Section V, Article 4 and API Std 650 Annex U.3.5. For welds when RT is used for the requirements of 7.3.2.1, ASME Section V.  VB: API Std 650, Sections 8.6.2, 8.6.5, 8.6.6, 8.6.7, and 8.6.8  VE: None  Tracer Gas: API Std 650, Section 8.6.11.a


Q&A Practice 3 API 653 PREPARATORY IMPORTANT OPEN BOOK QUESTIONS



My Self Study Notes QQ

: API

47610017

API 653 PREPARATORY PREPARATORY IMPORTANT OPEN BOOK QUESTIONS A PI 653 Third hird / Fifth Fifth Editi Ed itio o ns No.

1

QUESTION ION

C a lculate lcula te the t min. min. welded we lded tank shell

C ODE

CLAUSE

A PI653 PI653

4.3.3 .3.3.1 .1

min is calculated as follows: a) When determining the minimum acceptable thickness for an entire shell course, t min

b) When determining the minimum acceptable thickness for any other portions of a shell course (such as a locally thinned area or any other min is calculated as follows: location of interest), t min

Where: t is the minimum acceptable thickness, in inches for each course as calculated from the above equation; min shall not be less than 0.1 in. for any tank course; however, t min D is the nominal diameter of tank, in feet (ft); H is the height from the bottom of the shell course under consideration to the maximum liq uid level when evaluating an entire shell course, in feet (ft); or is the height from the bottom of the length L (see 4.3.2.1) from the lowest point of the bottom of L of the locally thinned area to the maximum liquid level, in feet (ft); or is the height from the lowest point within any location of interest to the maximum liquid level, in feet (ft); G is the highest specific gravity of the contents; min min



: API

47610017

is the maximum allowable stress in pound force per square inch (lbf/in.2); use the smaller of 0.80Y or 0.429T for bottom and second course; use the smaller of 0.88Y or 0.472T for all other courses. Allowable shell stresses are shown Table 4.1 for materials listed in the current and previous editions of API 12C and API 650; S

NOTE for reconstructed tanks,

S

shall be in accordance with the current applicable standard;

is the specified minimum yield strength of the plate; use 30,000 lbf/in.2 if not known; T is the smaller of the specified minimum tensile strength of the plate or 80,000 lbf/in.2; use 55,000 lbf/in.2 if not known; E is the original joint efficiency for the tank. Use Table 4.2 if original E is unknown. E = 1.0 when evaluating the retirement thickness in a corroded plate, when away from welds or joints by at least the greater of 1 in. or twice the plate thickness. Y

2

What Wha t is the max ma ximum a llo llo wa b le stre tre ss for fo r b o ttom & sec o nd c our ou rse

A PI653 PI653

4.3.3. 4.3.3.1 1

3.

To c hange ha nge the servic ervic e of the tank to a bove bo ve 200° 200°F F what wha t req uir uirements eme nts a re to be met

A PI653 PI653

4.2. 4.2.4. 4.4 4

4.2.4.3 4.2.4. 3 Operation at Elevated Temperatur e All requirements of API 650, Annex M, shall be considered before changing the service of a tank to operation at temperatures above 200 °F.


My Self Study Notes QQ 4.

: API

47610017

What Wha t is the max ma ximum a llo llo wa b le stress tress for fo r rec o nstr nstruc ucted ted tank ta nk

A PI653 PI653

4.3.3. 4.3.3.1 1

NOTE 6 The allowable stresses for reconstructed tanks are tabulated in API 650, Table 5-2a or 5-2b or calculated per 8.4 of this standard. 5.

Wha Whatt is the max ma ximum a llo llo wa b le stre tre ss for revited evite d tank ta nk

A PI653 PI653

4.3.4. 4.3.4.1 1

4.3.4.1 The minimum acceptable thickness for riveted tank shells shall be calculated using the equation in 4.3.3.1 except that the following allowable stress criteria and joint efficiencies shall be used: 2 S is 21,000 lbf/in. ; E is 1.0 for shell plate 6 in. or more away from rivets. See Table 4.3 for joint efficiencies for locations within 6 in. of rivets. 6.

A nnular nnula r b o ttom p late thicknes thickne ss (Sp (Sp . G r. < 1.0) 1.0)

Table 4.5—Annular Bottom Plate Thicknesses (in.) (Product Specific Gravity < 1.0)


A PI653 PI653

Ta b le 4-4


: API

47610017

7.

A ssessme essment nt o f the sa fe use use o f a tank ta nk c ons on struc truc ted o f unknown unknow n materi ma teria a ls

A PI653 PI653

Fig Fig . 5.2

8.

What Wha t rec ords shall ha ll be maint ma inta a ined by the O wner wne r / O pe ra tor

A PI65 PI653

6.8. 6.8.1 1

6.8 Records 6.8.1 General Inspection records form the basis of a scheduled inspection/maintenance program. (It is recognized that records may not exist for older tanks, and judgments must be based on experience with tanks in similar services.) The owner/ operator shall maintain a complete record file consisting of three types of records, namely: 1. construction records, 2. inspection history, and 3. repair/ alteration history.


My Self Study Notes QQ 9.

: API

47610017

What Wha t a re the material ma terial sp e c ific ific a tio tio ns for fo r struc tructur tura a l materi ma teria a ls

A PI653 PI653

7.3.2 7.3.2

7.3 Original Ma 7.3 Materials terials fo r Re Reconst const ructed Ta Tanks nks 7.3.1 7.3 .1 Shell and Bot tom Plates Welded Welded to t o the Shell 7.3.1.1 All 7.3.1.1 All shell plate materials materials and bottom plates plates welded welded to the shell shell shall shall be identified. identified. Materials Materials identified identified by original contract drawings, API nameplates, or other suitable documentation do not require further identification. Material not identified shall be tested and identified by the requirements as outlined in 7.3.1.2. After identification, determination shall be made as to suitability of the material for intended service. 7.3.1.2 Each individual plate for which adequate identification does not exist shall be subjected to chemical analysis and mechanical tests as required in ASTM A6 and ASTM A370 including Charpy V-notch. Impact values shall satisfy the requirements of API 650, Section 4.2.9, Section 4.2.10, Section 4.2.11, and Table 4-4a or Table 4-4b. When the direction of rolling is not definitely known, two tension specimens shall be taken at right angles to each other from a corner of each plate, and one of those test specimens must meet the specification requirements. 7.3.1.3 For known materials, all shell plates and bottom plates welded to the shell shall meet, as a minimum, the chemistry and mechanical properties of material specified for the application with regard to thickness and design metal temperature given in API 650, Figure 4-1a or Figure 4-1b.


My Self Study Notes QQ 10. 10.

: API

47610017

Shell de sign for a rec rec onstr onstructed uc ted tank, ta nk, with materi ma teria a ls whos who se allowa ble str stress esses a re not given in Ta ble 3-2 of A PI 650, 650, what a llow llowa a ble stress tresses are to be taken

API653

8.4.2

8.4 Shell Shell De Desig sig n 8.4.1 Thickness to be used for each shell course when checking tank design shall be based on measurements taken within 180 days prior to relocation. (See 4.3.2 for measuring procedure, number, and locations of measured thicknesses.) 8.4.2 The maximum design liquid level for product shall be determined by calculating the maximum design liquid level for each shell course based on the specific gravity of the product, the actual thickness measured for each shell course, the allowable stress for the material in each course, and the design method to be used. The allowable stress for the material shall be determined using API 650, Table 5-2a or Table 5-2b. For material not listed in Table 5-2a or Table 5-2b, an allowable stress value of the lesser of 2/3 yield strength or 2/5 tensile strength shall be used. 8.4.3 The maximum liquid level for hydrostatic test shall be determined by using the actual thickness measured for each shell course, the allowable stress for the material in each course, and the design method to be used. The allowable stress for the material shall be determined using API 650, Table 5-2a or Table 5-2b. For material not listed in Table 5-2a or Table 5-2b, an allowable stress value of the lesser of 3/4 yield strength or 3/7 tensile strength shall be used.



: API

47610017

After Afte r the valve has be en ins installed talled on the flang flange e at a t what wha t press pressure ure the press pressure ure test test shall ha ll be performed

API653

9.14.5.3

9.14.5.3 After the reinforcin 9.14.5.3 After reinforcing g plate has has been welded welded to the the shell and and NDE performed, performed, the pad shall shall be pneumatically pneumatically tested by the procedure described in API 650, Section 7.3.4. After the valve has been installed on the flange, a pressure test at least 1.5 times the hydrostatic head shall be performed on the nozzle prior to mounting the hot tap machine, which shall be bolted to the valve. The required pressure for the pressure test shall be at least the value computed by the following equation:

where is the height of tank shell in inches (in.); G is the specific gravity of product stored, as specified by purchaser. The specific gravity shall not be less than 1.0; γw is the density of water in pound force for cubic inch (lbf/in.3).

H 2

12. 12.

In tank rec o nstr nstruc ucti tion, on, new verti vertic c a l joints joints in a djac dja c ent shell shell c ourses ourses shall ha ll be offs o ffset et by what wha t minimu minimum m dis d istanc e

API653

10.4.2.1

10.4.2 Welding 10.4.2.1 Provisions shall be made during the reconstruction of a tank to ensure that weld spacing requirements of Figure 9.1 are maintained. New vertical joints in adjacent shell courses, made in accordance with 10.3.3.1, shall not be aligned but shall be offset from each other a minimum distance of 5 t , where t is the plate thickness of the thicker course at the point of the offset. 13. 13.

During During tank rec onstr onstructi uc tion on / rep rep a ir what wha t is the max ma ximum imum a llow llowed ed under unde rc utting utting for for vertica vertica l join joints ts

API653

10.4.2.5

10.4.2.5 The edges of all welds shall merge with the surface of the plate without a sharp angle. Maximum permissible weld undercut shall be in accordance with API 650, Section 7.2.1.4 and Section 8.5.1 b).



: API

47610017

What Wha t is the max ma ximum re inforce inforc e ment a llo llo wed we d for hor ho rizo izo ntal nta l joint o f ¾” p late

Table Ta ble 10.1—Ma 10.1—Maxim xim um Thi ckn cknesses esses on Ne New w Welds


A PI653 PI653

Ta b le 10-1 10-1


: API

47610017

In c o mpleted mplete d horiz horizontal onta l butt joints joints, the uppe upp e r p late shall ha ll not projec t b eyond eyo nd the the lower lowe r plate pla te by how much

API653

10.4.4.2

10.4.4 Shells 10.4.4 10.4.4.1 Plates to be joined by butt welding shall be matched accurately and retained in position during welding. Misalignment in completed vertical joints over 5/8-in. thick shall not exceed 10 % of the plate thickness, with a maximum of 1/8 in. Misalignment in joints 5/8-in. thick or less shall not exceed 1/16 in. Vertical joints shall be completed before the lower horizontal weld is made. 10.4.4.2 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 1/8 in., except that a projection of 1/16 in. is acceptable for upper plates less than 5/16-in. thick. 10.4.4.3 For horizontal and vertical joints in tank shell courses constructed of material over 1 1/2-in. thick (based on the thickness of the thicker plate at the joint), multi-pass weld procedures are required, with no pass more than 3/4-in. thick permitted. A minimum preheat of 200 °F is required of these welds. 16. 16.

C a lculatio lc ulation n o f Internal Bo ttom se ttlem ttlement ent o r b ulges ulge s

A PI653 PI653

B.3.3 .3.3

B.3.3 Internal B.3.3 Internal Bott om Settlements or Bulges Measure the bulge or depression. The permissible bulge or depression is given by the following equation (see Note). BB = 0.37 R where BB is maximum height of bulge or depth of local depression, in inches; R is radius of inscribed circle in bulged area or local depression, in feet. Figure B.10 is a graphical representation of this equation. 17. 17.

Problem Prob lem on e d ge se ttle ttle ment me nt

A PI653 PI653

Fig Fig B-10

Tanks with larger edge settlements are to be repaired, or have detailed analysis of bottom, and bottom-to-shell Junction Welds in tanks with settlement greater than or equal 75 % of Bew, and larger than 2 in., are to be examined with magnetic particle or liquid penetrant methods



: API

47610017

For welding we lding A 516 516 G r 70 materi ma teria a ls wha t elec ele c tro tro d e c lassifi lassific c a tion shall ha ll b e use use d A PI650 PI650 2.8 7.2.1.11 Lo w-hydrogen w-hydrog en elec e lectr trod od es shal ha ll b e used used for all manua ma nuall metalmeta l-a a rc welds we lds in annul a nnula a r rings a nd shell

c ourses, ourses, inc including luding the a tta tta c hment of o f the firs first shell shell co urs urse to b o tto tto m or annul a nnula a r p lates, a s follo follo ws. ws. a ) Where the plates p lates are thic thic ker than 12.5 mm (1/ (1/ 2 in.) in.) (ba sed o n the thic thic kness kness o f the thic thic ker member memb er being be ing join joined ed)) a nd ma ma de of o f materi materia l from from Group Groups s I–II –III. b) For all thicknesses when the plates are made of material from Groups IV, IVA, V, and VI.


Reading4 POINTS TO RECALL




Day 1


1. API 653 is code code used used for for inspe inspecti ction, on, repair repair,, and and altera alteratio tion n for for the the aboveground storage tanks which whi ch are pla pl aced in Servi Service ce. API 650 is the basic construction code for making New New Tanks. Tanks . 2. API API 650 650 and and API API 653 653 are are use used d for for abov aboveg egro roun und d stor storag age e tan tanks ks at atmospheric pressure (maximum 2.5 psi above atmospheric) and temperatures not exceeding 90ºC. (200ºF) 3. Desi Design gn meta metall tem tempe pera ratu ture re of of tan tank k is assu assume med d to to be be 8ºC 8ºC (15º (15º F) abo above ve the the lowest one day mean temperature of tank site. 4. Where Where necess necessary ary,, as as per per Fig. Fig. 2-1 (API (API 650) 650),, the the tank tank mater material ials s shal shalll be checked against brittle failure by conducting impact testing. Acceptance Acceptance criteria shall be as per Table 2-4.


Table 4.5b— 4.5b—M Minim in imum um Impact Test Test Requ Requir ireme ement nts s for fo r Plates Plates (USC) USC) (See Note)


5. If averag average e valu value e of of 3 specim specimen en is < spec specifi ified ed averag average e valu value e (SAV (SAV)) — reject. But if average value of 3 specimen ≥ SAV and, Value of one specimen is < SAV but ≥ 2/3 2/3 SAV SAV — acce accept pt Value of one one specimen specimen is < SAV and and also < 2/3 2/3 SAV — retest retest Value of two two specimen specimen is < SAV SAV — retest retest On retest for b and c all three specimen ≥ SA SAV V — acce accept pt


6. The The req requi uire red d thi thick ckne ness ss of shel shelll pla plate tes s for for tank tanks s up up to to 60 60 m (200 (200 feet feet)) diameter shall be greater of t d or tt:

Where: D = Tank Diameter m (ft) H = Height shell course from top liquid level in m (ft) G = Specific Gravity of liquid to be sto stored Sd / St St = All Allow owab able le stre stress ss for for des desig ign n and and hydr hydros osta tati tic c con condi diti tion ons s in in Mpa Mpa (psi (psi)) C.A. = Corrosio Corrosion n allowan allowance ce in mm (in) (in)


7. Shel Shelll thic thickn knes ess s calc calcul ulat ated ed abo above ve (po (poin intt no. no. 6) shal shalll not not be less less than than tha thatt required required by Diameter Diameter – Thickness Thickness table table in API 650. (3.6.1 (3.6.1.1) .1) 8. Valu Values es of Sd and and St St are are take taken n fro from m Tab Table le 3-2 3-2 of of API API 650. 650. For For unl unlis iste ted d material: Sd = Lower Lower of 2/3 2/3 (Y.S) (Y.S) or 2/5 (T.S. (T.S.)) and St = Lower Lower of ¾ (Y.S) (Y.S) or 3/7 3/7 (T.S.) (T.S.) 9. Mini Minimu mum m nomi nomina nall thic thickn knes ess s excl exclud uding ing corro corrosi sion on all allow owan ance ce for for roo rooff plat plate e shall be 5 mm (3/16”) and for bottom plate shall be 6 mm (1/4”).


10. All nozzles, nozzles, manholes manholes and and other other openings openings shall shall have dimens dimensions ions thickness, reinforcement reinforcement plates and weld sizes as per tables 3-6 and 3-7 of API 650. 11. Radiograph Radiography y inspection inspection is required required for for all shell butt butt welds and and annular annular plate butt welds and insert plates for manhole and nozzles. 10. For shell shell plates plates the number number of radiograp radiographs hs required required depend depend on whether whether the plate thickness is up to 10 mm (3/8), or above 10 mm to 25 mm (3/8” – 1”) or above 25 mm (1”). (Fig. 6-1 of API 650). 650).


13.Radiography is also required on: 100% length of butt welds joining insert i nsert plate to shell, and Annular bottom plate radial joints (1 spot on 10% of radial welds if double double butt welded and 1 spot on 50% of radial welds if single welded with backing strip.)


13. 13. Radi Radiog ogra raph phy y is als also o requ requir ired ed on: on: 100% length of butt welds joining insert plate to shell, and Annular bottom plate radial joints (1 spot on 10% of radial welds if double butt welded and 1 spot on 50% of radial welds if single welded with backing strip.)


Day 2


According to API 653, “Repairs” “Repairs” means any work work necessary to maintain or restore the safe operating conditions (as per original design). “Alteration” means any work that changes the dimensions and/or configuration of tank (changing original safe operating conditions). “ Authori zed inspe i nspection ction agency” gency” is any one of the following (who employ API tank inspector): inspector): An owner operator operator Subcontractor Subcontractor to owner operator Inspection organization of jurisdiction Inspection organization of insurance company “ Brea Break-ove k-overr point” means area of tank bottom where settlement begins. “ Change hange of service” service” means change in fluid stored and having different specific gravity or corrosivity or different temperature or pressure.


“ Critical rit ical zone” means portion of tank bottom within 3 inches of shell inside and measured radically inwards. “ Repair orga or ganiza nizatio tion” n” means any of the following who carries out repairs / alterations according to API 653. • Owner-user • Subcontractor to owner-user • Subc Subcon ontr trac acto torr auth author oriz ized ed or app appro rove ved d by by juri jurisd sdic icti tion on

Tank roof plates which are so corroded that there are through holes or the average thickness is less than 0.09 inch in any 100 sq. inch area, then plates must be repaired or replaced, i.e., tank cannot be permitted to continue operation.


•

If tank tank serv service ice is to be change changed d resu resulti lting ng in in incr increas ease e of of inte interna rnall pres pressur sure e or or operation operation above above 90º C (200º (200º F), then then require requirement ments s of API API Appendix Appendix F and M must be fulfilled respectively. If service changes lower temperature then material must must be suitable suitable as per impact impact test requirements of API 650. Tank shell evaluation: 5 step method.

•

Widel idely y scat scatttere ered pit pits s can can be be ig ignore nored d ifif: 1. No pit pit dept depth h resul results ts in in shell shell thic thickne kness ss bein being g less less than than half half the the requir required ed thk thk – excl exclud udin ing g C. A. 2. Sum of pit pit dime dimensi nsions ons alon along g any vert vertica icall line line does does not exce exceed ed 2 inches in a total length of 8”.


•

Mini Minimu mum m thi thick ckne ness ss for for bot botto tom m pla plate tes s is is giv given en by: by: • Anul Anular ar plat plates es (pro (produ duct ct sp. sp. gr. gr. < 1.0) 1.0):: Tabl Table e 4-3 4-3 (API (API 653) 653) • (Product sp. gr. ≥ 1.0): Table 3-1 (API 650) • Othe Otherr bo botto ttom pla plates: es: Tab Table le 6-1 (AP (API 653 653))

Min. thicknes thickness s in “criti “critical cal zone” zone” is smaller smaller of:(but of:(but not less than 0.1”) Half of original bottom thickness in critical zone, and Half of tmin for first shell course. •

Tank Tanks s desi design gned ed pri prior or to to API API 650 650 (7th (7th edi editi tion on,, 1980 1980)) may may be asse assess ssed ed for for brittle failure as per Fig. 5.2.

•

Tank Tanks s are are not not like likely ly to to fail fail in in brit brittl tle e fail failur ure e if thic thickn knes ess s is not not mor more e than than ½” ½” or shell temperature temperature is not less than 60º F or stress level is less than than 7,000 psi.


Day 3


Inspection Frequency (External) shall not exceed following • Rout Routin inee-in in Serv Servic ice e insp inspec ecti tion on ever every y one one mont month. h. • Ex Exte tern rnal al insp inspec ecti tion on (vis (visua uall by auth author oriz ized ed ins inspe pect ctor or): ): Low Lower er of one one-f -fou ourt rth h remaining life (RCA/4N) or 5 years. • Ultr Ultras ason onic ic thi thick ckne ness ss ins inspe pect ctio ion n (ext (exter erna nal) l) of of shel shell. l. when corrosi corrosion on rate is not not known known — maximum maximum 5 years years when corros corrosion ion rate rate is known known — lower of : half remaining life (RCA/2N) or 15 years Inspection Frequency (Internal) shall not exceed: • Base Based d on on MRT MRT cal calcu cula lati tion ons, s, as per per “Or “Or”” calc calcul ulat ated ed but but not not exce exceed edin ing g 20 20 years (25/30 yrs) • If corro corrosi sion on rate rates s are are not not kno known wn:: Actu Actual al bot botto tom m thi thick ckne ness ss shal shalll be be determined not later than 10 years. (could be inservice or out of service)


•

•

Altern Alte rnat ativ ive e to poin pointt no. no. 2 abo above ve for for int inter erna nall insp inspec ecti tion on int inter erva vall may may be altered based on RBI. The RBI basis shall be reviewed at intervals not exceeding 10 years by authorized inspector and tank engineer. If ther there e is acce access ss to tank tank bott bottom om to det deter ermi mine ne bott bottom om thic thickn knes ess, s, exte extern rnal ally ly,, such inspection may be used in lieu of internal inspection. (Point No. 2)

Inspection records include: • Perm Perman ane ent Reco Record rds s (Ta (Tan nk con const stru ruc ction ion dat data a) • Inspe nspec ction ion his histtory ory (Pr (Prog ogre res ssiv sive Rec Recor ords ds)) • Repa Repair ir/a /alt lter erat atio ion n hist histor ory y (Rep (Repai air/ r/al alte tera rati tion on reco record rds) s)


New materials for repair/alteration/ reconstruction: All plate material used for shell and the bottom plates welded to shell shall be identified. Thickness of shell plates to be used for checking the tank design shall be within 180 days before relocation. r elocation. The strength values Sd and St for reconstructed reconstructed tank shall be on the basis of allowable stress as per table 3-2 of API 650. The replacement shell plate thickness ≥ thickness of the shell course where replacement is proposed and dimensions and spacing shall be as per Figure 9-1.


Lap-welded patch plates can be used only if: • owner specifies • only on shell plates ≤ ½ inch • must must be with within in spac spacin ing g req requi uire reme ment nts s as as per per Fig. Fig. 9-1 9-1 • maxi maximu mum m siz size e 48” 48” vert vertic ical al x 72 72 hor horiz izon onta tall and and minim inimum um dime dimens nsio ion n 4” 4” • area areas s on on whi which ch lap lap pat patch ch is to be put put sha shallll be UT chec checke ked d • lap on lap is not permitted


All shell plate defects like the cracks, gauges, tears, widely scattered scattered .pits and and corroded areas shall be evaluated case by case as per chapter 4 of API 653. New reinforcements reinforcements can can be added added to existing existing unreinforced unreinforced nozzles as per Fig. Fig. 9-3a and 9-3b. Repairs within critical zone of the bottom require additional precautions like “Tombstone” type patch patch and additional PT or MPI testing after after visual examination of patch welds, and weld shall be made by minimum 2 passes. If impact test was not done on original tank material, the hot taps shall be limited to NPS 4 (max). Toe-to-toe minimum minimum spacing spacing between hot tap and adjacent nozzle nozzle shall be = √(RT) where R= tank shell radius in inches T is shell plate thickness in inches.


Day 4


For tank relocation, relocation, the the bottom, shell or roof may may be cut in any size from existing tank so that the pieces are suitable for transportation. For dismantling the tank the bottom may may be cut 12” away from shell shell to bottom weld, if entire bottom plates are to be used. Alternatively cut cut the bottom bottom and shell shell at 1/2” from toe of shell to to bottom weld and discard the weld portion. For rest of the bottom, bottom, de-seaming de-seaming of welds or cutting 2” away from weld may be done. Shell plates ≤ ½” thk may be dismantle dismantled d by by cuttin cutting g throug through h weld weld witho without ut removing removing HAZ. HAZ. If shell plate plate thk > ½”, discard discard welds welds + HAZ. Alternatively, shell plates may may be cut 6” 6” away from existing existing welds.


NDT for Repair / Alteration: PT / MT: For all fillet welds and fill-up (weld-build up) during repair or alteration Radiography: New welds during repair or alteration between the plates such as: New to to new plates plates — same same as API 650 650 New to old plates or old to old plates. Additional examination: 1 spot for each 50 feet for horizontal weld 1 spot on each vertical weld 1 radiograph on each T-joint Repair Repair of old butt-wel butt-welds ds — entire entire length length of repair repair A full hydrostatic hydrostatic test (held for 24 hours) is required on major repairs and major alterations which include: Installation of nozzles larger than NPS 12 below liquid level


Repair / Replacement of more than 12” 12” length of vertical weld in shell or radial radial weld weld in in anula anularr plates plates Any repair / replacement on on shell to bottom bottom weld Jacking of tank shell Exemption for hydrotest is possible only only if owner / operator and the tank engineer give the exemption in writing. Hydrostatic test of reconstructed tank is compulsory. Out of plumbness for reconstructed tank is 1/100 of the tank height subject to maximum 5 inches. For tank settlement survey, the number of elevation measurement points for tank diameter D ft. is given by: N=D/10, but minimum 8. Permitted internal settlement settlement (for bulge or depression) depression) is given by: B = 0.37 R Where B = Max. height of bulge or depth of settlement (inches) And R = Radius Radius of largest inscribing circle (feet) (feet)


Based on Fig. B-10, and B-11 maximum allowable edge settlement is worked out depending on settled area being approximately parallel or perpendicular to shell. As per API RP 575, the the grounding connection connection inspection shall be included is external visual inspection. Total resistance from tank to soil should not exceed approximately 25 ohms. Ultrasonic thickness measurements as a minimum must be made on at least one TML on each shell course. TMLs also shall be be established on top uncoated portion of shell for floating roof tanks. For internal inspection of tank bottoms, a preliminary random thickness scanning survey is carried out in X pattern across the tank and along the circumference. If significant corrosion is detected, entire bottom shall be scanned. For internal inspection inspection of shell, shell, the major major areas of focus focus shall be the vapour vapour space, liquid-vapour interface and the bottom area.


Leak testing of shell may be done hydrostatically or by using diesel test or by vacuum box test. Leak testing of bottom may be done by: Using vacuum box test By construction of clay dam around tank and filling under side by water (observe seepage inside) Apply seal to to tank outer outer perimeter and introduce compressed air air below tank bottom, check welds by applying soap solution or by observing bubbles by filling filling inside inside of tank tank by water water for for 6” height height By injecting inert inert gas with tracer tracer gas under the tank and using “sniffers” “sniffers” inside to detect leakage Hammer test is never carried out on cast iron parts. Corrosion rate curves are helpful as an important record of corrosion behavior behavior of tank in past and anticipated remaining life in future.


Day 5


WPS gives parameters to be used in production job, and must be within ranges qualified by the PQR test. Essential variables (EV), if changed require new procedure qualification. Nonessential variables (NEV) may be changed without new procedure qualification. Bend test crack shall not not exceed 1/8” in any direction direction for face bend, root bend or side bend. Supplementary essential essential variables (SEV) are considered as (EV) only if there is impact impact strength strength requirement. requirement. Otherwise they are are “non-essential” “non-essential” variables. Tensile Tensile test for for procedure procedure qualificatio qualification n is passed if failure failure is in: Weld metal at strength>= Base metal SMTS or Base metal at strength>= 95% of base metal SMTS.


P-numbers represent parent metal groupings of similar composition and properties, i.e., similar strength and ductility. F-numbers give similar usability aspects of filler material. A-numbers give similar chem. comp. In “As welded” condition For performance, 1G is flat, 2G is horizontal, 3G is vertical and 4G is overhead position. Pipe 5G qualifies 1G, 3G and 4G, but pipe 6G qualifies all positions. Welders who have not welded welded for more more than 6 months months on a process, their qualification will expire for that process. In Galvanic corrosion, current flows from anode to cathode, therefore anode will lose metal and cathode will wil l gain. If we make the “component to be protected” cathodic with respect to surrounding, it will will not lose metal, metal, thus will will be protected.


As soil resistivity resistivity goes up, soil is less corrosive and vice-versa. Soil resistivity < 500 ohm-cm is highly corrosive, 10,000 ohm-cm, is least corrosive.) Ref. Table 1-API 651 Cathodic protection methods: Galvanic and impressed current Galvanic current: Easy to install, cheap, easy to maintain, but limited use. (Not suitable for large structure) Impressed current: Expensive, but more effective, suitable for large structures. Requires constant monitoring. CP system survey intervals: Impressed current: Rectif Rectifier ier (power (power source source)) — Max. Max. 2 mont months hs Other Other compone components nts — Max. 1 year year Galvanic System (sacrificial anode system): Annually CP survey records should be maintained normally for 5 years.


There are two main classes of linings: Equal to or less than 20 mils (thin film linings) and Greater than 20 mils (thick film linings). The principal advantages for thin-film lining are lower cost and ease of application compared to thick-film lining systems. 15. Thick-film, re reinforced lilining are are less su susceptible to to me mechanical damage than thin film linings. They can provide provide sufficient strength to bridge over small perforations of the supporting steel bottom that may develop due to external corrosion. Temperature during blast blast cleaning and applying the linings shall be 3°C (5°F) above the dew-point temperature and relative humidity not to exceed 80%.


API651: A PI651: 11.4.7 sufficient to to demonstrate demonstrate the need for corrosion control control measures  Records sufficient should be retained as long as the facility involved involved remains in service. 

Records related to the effectiveness of cathodic protection should be retained for a period of five years unless a shorter period is specifically specifically allowed by regulation.


Day 6


GENERAL: ASME Sec. V is NDT procedure/methods procedure/methods code and is applicable only if it is referenced by the relevant construction code. The extent of NDT and acceptance standards is given in relevant construction code.

NDT equipment and their calibration shall be as per ASME Sec. V. Examiner is NDT person in employment of fabricator or repair organization. Inspector means Authorized Authorized Inspector Inspector who finally accepts/rejects accepts/rejects NDT results. FOR RT: Satisfactory radiograph shall meet requirements of density and IQI image (2T hole for hole type and designated wire for wire type). Backscatter: Light Light ima image ge of of B on dark dark backg backgrou round nd - Unacce Unaccepta ptable ble Density Limitations: Min 1.8 for X Ray / 2.0 for G-Ray Max 4.0 for X / G Ray Density Variation Variatio n = -15 % to + 30% Doub Double le wal walll view viewin ing g (DWD (DWDI) I) - Up to to 3.5” 3.5” outs outsid ide e diam diamet eter er


Penetrameter Penetrameter Selection: Table T-276. T-276. Thickness Thickness includes weld reinforcement. reinforcement. But not backing. (?) Penetrameter shall be normally placed on source side. If not possible, it may be placed on film side with lead letter “F”. T276.2 (a) Welds With Reinforcements. The thickness on which the IQI is based is the nominal single-wall thickness plus the estimated weld reinforcement not to exceed the maximum maximum permitted permitted by the referencing Code Section. Backing rings or strips shall not be be considered as as part of the the thickness in IQI selection. selection. The actual measurement of the weld reinforcement is not required.


FOR PT: Control of Contaminants: Contaminants: Sulphur (for Nickel alloys) shall not exceed 1% of residue. Chlorine + Fluorine (for S.S. and Titanium) shall not exceed 1% of residue. Temp. shall be between 10oC to 52oC, for standard procedures. Penetrants are colour (visible) type and fluorescent type. Each of these have: water washable post emulsifying solvent removable Thus, total 6 categories of penetrant are available.

Emulsifier is applied after applying penetrant and required dwell time is completed. Lipopholic Lipopholic emulsifie emulsifierr is applied without without pre-rinsing pre-rinsing.. Hydropholi Hydropholic c emulsifie emulsifierr is applied after after pre-rinsing. pre-rinsing. For dwell time for penetrant and developer refer Table T-672. After applying developer, interpretation interpretation shall be done within 10 to 60 minutes. minutes. All penetrant materials should should be from same manufacturer. manufacturer.


FOR MT: Prod Technique: Use direct (rectified) current for magnetization magnetization Prod Prod spa spaci cing ng 3” 3” to 8” 8” Useful for surface and sub-surface defects.

Yoke Technique: Use D.C. or A.C. or permanent magnet Suitable for surface defects only. Calibration: Equipment Ammeter Ammeter to be calibrated once a year comparing with standard Ammeter, take 3 readings. readings. Deviation shall not exceed exceed ±10% of full scale. Lifting Power of Yokes AC shall have lifting power of at least 4.5 4.5 kg (10 lbs.) lbs.) DC shall have lifting power of at least 18.1 kg (40 lbs.) Minimum two examinations examinations on each each area, the second second is perpendicular to first


SE-797 UT MEASUREMENT: Pulse-echo method can be adopted up to 200°F Apparatus: 3 types CRT read out CRT + direct read out Direct thickness read out Search Units: 3 types - Straight Straight beam contact contact type Delay line type (delay block to minimize dead zone) Dual element type. There are two crystals set at a small range. Low roof angle used for higher range and higher angle for low range.


High thickness measurement: measurement: Use of multiple echoes is made. (i.e., for thickness between 50 mm and 60mm, use 10mm calibration block then 5th back echo will be 50 mm and 6th will be 60mm. Set the 5 th echo to zero and 6th at the screen range. The screen is calibrated to 50-60mm. While taking measurement for high temperature condition a positive error of 1% per 55°C (100°F) results. results. Hence Hence temperatur temperature e correction correction is necessary. necessary. CRT read out is i s recommended on corroded and rough surface.






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