API 510 Question & Answer

API /QUEST/RAJI/MARMUL API 510 Question and answers. Pressure Vessel inspection code Maintenance Inspection, Rating, Repair and alteration. 1) Which is current edition and year of edition of API 510? Eighth edition, June 1997 ADDENDUM 1 DEC 1998, ADDENDUM 2 DEC 2000 ADDENDUM 3 DEC 2001, ADDENDUM 4 Aug 2003 2) Which is the year of 1st edition of API 510? 1958. 3) When did the new edition, addenda or revision become effective? After 6 month of its issuance. 4) What are the applications of this code? This inspection code applies to vessels constructed in accordance with the API/ASME code for unfired pressure vessels for petroleum liquid and gases sec VIII of the ASME code and other recognised pressure codes to non standard vessels. 5) What are non –standard vessels? A vessel fabricated to a recognized construction code but has lost its name plate or stamping. & a vessel not fabricated to a recognised construction code and meeting no known recognised standard. 6) Do API 510 is applicable to new construction? No this Inspection code is only applicable to vessels that have been placed in service including items like that ,all pressure vessels used for exploration and production( E&P) 6) What are the conditions of applicability of this code to a vessel that have been placed in service? If it has been inspected by an authorized inspection agency, or repaired by a repair organisation, as defined in sec 3.15, I.e. The work necessary to restore a vessel to a condition suitable for safe operations at the design conditions. If any repair changes the design temperature or pressure, the requirement for re-rating shall be satisfied. The repair can be addition or replacement of pressure or non-pressure parts that do not change the rating of the vessel. 7) Which section of API -510 is not applicable to E&P services? Section 6 8) Which section of API -510 is applicable to E&P services? Section 8 9) Does, Pressure vessels installed on movable structures are covered by API 510 or not? No 10) Does API510 recognise fitness for service concept for evaluating in-service degradation of pressure containing components? Yes API 579 provides detailed assessment procedures. 11) What is meant by alteration? A physical change in any component or a re-rating that has design implication that affect the pressure containing capability of a pressure vessel beyond the scope of the items described in existing data reports. 12) Any comparable or duplicate replacement. Is it an alteration? No 13) The addition of any reinforced nozzles, less than or equal to the size of the existing reinforced nozzles, or the addition of nozzles not requiring reinforcement. Is it an alteration? No

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API /QUEST/RAJI/MARMUL API 510 Question and answers. 14) Which parts of ASME code can be applied for this code? ASME Code is written for new construction, how ever most of the technical requirement for design, welding, examination and material can be applied in the maintenance inspection also. 15) During in-service inspection, if some items are covered by requirements both in ASME and API 510, and if there is a conflict between these codes, which code will govern? API 510 shall govern. 16) Who is Authorised pressure vessel inspector? An employ of an authorised inspection agency, Who is qualified and certified to perform inspections under this inspection code. 17) What is the meaning of Construction code? The code or standard to which a vessel was originally built. 18) Can we use API 510 code , to repair a pressure vessel which was constructed as per BS- 5500 pressure vessel code? Yes, as per section 1 refer general application. 19) What is Maximum allowable working pressure? The maximum gauge pressure permitted at the top of pressure vessel in it operating position for a designated temperature. This pressure is based on calculations using minimum thickness for all critical vessel elements. Exclusive of thickness designated for corrosion and loading other than pressure. 20) What is Minimum allowable shell thickness? The thickness required for each element of a vessel, the minimum allowable shell thickness is based on calculations that consider, temperature, pressure & loadings. 21) What is meant by pressure vessel? A container designed to withstand, internal or external pressure, this pressure may be imposed by an external source by the application of heat from a direct or indirect source or by any combination there off. This definition includes unfired steam generators and other vapour generating vessels which use heat from the operations of a processing system or other indirect heat source. 22) What is Quality assurance? A planned and systematic preventive action required to determine if materials equipments or service will meet specified requirements so that equipment will perform satisfactorily in service 23) What is repair? The work necessary to restore a vessel to condition suitable for safe operation at the design conditions. The repair can be the addition or replacement of pressure or non pressure parts that do not change the rating of the vessel. 24) What is meant by re-rating? A change in either temperature rating or maximum allowable working pressure rating or a change in both is called re-rating, in re-rating, the maximum allowable pressure and temperature may be increased or decreased, and some times it required combination of changes. De-rating below design condition is permissible, but temperature below minimum is decreased or pressure and temperature increased then additional mechanical test may be required. This will be considered as alteration. 25) What are the two main Responsibilities of the authorised pressure vessel inspector? Responsible to the owner –user for determining that the requirements of API 510 on inspection examinations and testing are met and shall be directly involved in the inspection activities. & all examination results must be evaluated and accepted by the API authorised pressure vessel inspector,

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API /QUEST/RAJI/MARMUL API 510 Question and answers. 26) Explain the eight steps for a GOOD inspection practice? A) Preparatory work required Explain the permit to work system, isolation requirement, confined space entry, tools and tackles, PPE, Knowledge of hazards involved, etc. B) Analysis of mode of deterioration and failure. Carry out the inspection, for finding out the following deterioration and failure, 1) Corrosion & Significant stress fluctuations or reversals in parts of equipments. Particularly at point of high secondary stress,( Example Due to expansion and contraction of the piping connected to the vessel nozzle, wind force, internal built in pressure and vacuum etc and temperature variations , can produce a stress , This can lead to fatigue failure. 2) Creep may occur in equipment if subjected temperatures above those for which it is designed. Since metals weaken at high temperatures such deterioration may cause failures. Creep is dependent on time, temperature, stress and material creep strength. 3) What are the factors, which has to be remembered for developing an inspection plan for equipment operating at elevated temperatures? Creep deformation and stress rupture. Creep crack growth Effect of hydrogen on creep Interaction of creep and fatigue. Possible metallurgical effects including a reduction in ductility. 4) Which is the low alloy steel, which is very prone to temper embrittlement? 2 ¼ cr -1Mo 5) What is temper embrittlement? It is a loss of ductility or notch toughness due to post weld heat treatment or high temperature services above 370 Degree centigrade. 5) What are the two appearances of corrosion? Uniform corrosion, Pitted type 6) How can we adjust the corrosion rate and Minimum actual thickness? It is being done in any inspection. Followed by a corrosion measurement technique, Such as ultra sonic or radiographic examination. Minimum thickness can be examined by the above non destructive method; the depth of the corrosion may be determined by gauging the uncorroded area such as the vicinity of the corroded Area. 27) Explain the evaluation method, for a corroded area of considerable size in which the circumferential stresses govern? What is the evaluation tolerance as per API 510? The least thickness along the most critical element of the area may be averaged over a longitudinal length not exceeding the following. Vessel A) For vessels with inside dia-meter less than or equal to 60 inches (150 cm), one half of the vessel dia meter or 20” (50 cm) which ever is smaller. Vessel B) for vessels with inside dia-meter more than or equal to 60 inches (150 cm), one third of the vessel dia meter or 40” (100 cm) which ever is smaller. 28) Explain the acceptance standard for widely scattered pits as per API 510? a) The remaining thickness below the pit is greater than one half the required thicknesses Remaining thickness = ½ the t required b) The total area of the pits does not exceed 7 squire inches (45 squire centimetres) within any 20 centimetre diameter circle.

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API /QUEST/RAJI/MARMUL API 510 Question and answers. C) The sum of there dimensions along any straight line with in the circle does not exceed 2” (5 cms). 28)

API 5.7, d Important.

Condition: - When the surface at a weld with a joint factor of other than 1.0 as well as surfaces remote from the weld is corroded, what is to be done as per API 510? An independent calculation using the appropriate weld joint factor must be made to determine, if the thickness at the weld or remote from the weld governs the allowable working pressure for this calculation. 30) What is the explanation of term, “surface at a weld”? Surface at a weld includes, one inch (2.5 cm) either side of the weld, measured from the toe of the weld. Or twice the minimum thickness on either side of the weld which ever is greater.

31) Fitness for service evaluation can be carried out as per API 579, how? To evaluate the metal loss in excess of the corrosion allowance, a fitness for service assessment may be performed, in accordance with the followings section of API RP 579, this assessment requires the use of a future corrosion allowance, which shall be established, based on section 6 of this inspection code. INSPECTION AND TESTING OF PRESSURE VESSELS AND PRESSURE section 6 RELIEVING DEVICES. 32) What is the external inspection frequency as per API 510/ At least every five years or when ever internal inspection is scheduled, which ever period is less. 33) What is the minimum frequency requirement of internal and on stream inspection as per API 510? 10 Years or one half of the estimated remaining service life of the vessel based on corrosion rate, which ever is less. 34) What is the minimum frequency of internal and on stream inspection as per API 510? In case where the remaining safe operating life is estimated to be less than 4 years. The inspection interval may be the full operating life up to a maximum of 2 years. 35) What is the on stream and internal inspection frequency if the vessel is mothballed or in non continuous operations? Same as the vessel is in the operation, under no circumstances, it shall not exceed 10years. 36) What is the external inspection frequency, if the vessel is mothballed or in non continuous operations? Same as the vessel, which is in operation (5 years) 37) Under what conditions, the on stream inspection, may be substituted for internal inspection? 1) When the size, configuration, or lack of access makes vessel entry for internal inspection physically impossible. 2) When the general corrosion rate of the vessel is know to be less than .005inches or (0.125mm/ year) and the estimated remaining life is greater than 10years.and all the following conditions are met. A) The corrosive character of the content, including the effect of trace components, API /2004

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API /QUEST/RAJI/MARMUL API 510 Question and answers. established by at least 5 years operation. B) .If no questionable conditions is disclosed by external inspection specified in 6.3 C) The operating temperature of the steel vessel shell does not exceed the lower temperature limit for the creep rupture range of the vessel material. D) If the vessel is not considered to be subjected to be environmental cracking or hydrogen damage from the fluid handle, RBI assessment as permitted by 6.2 can be done. E) If the vessel should not have a non integrally bonded liner, such as strip liner or plate liner.

Remaining service life /years = t actual - t required Corrosion rate t actual = wall thickness measured at the time of inspection. t required-= The design thickness as per drawing - corrosion allowance- manufacturer’s tolerance.

L/T Long term corrosion rate= t Initial – t Actual Time years (between t initial and t actual) S/T Short term corrosion rate= t previous – t Actual Time years (between t previous and t actual) L/T This can be calculated just by taking reading at single time at a location .if you understand the year of installation.

S/T The corrosion rate shall be calculated after two inspections at the same location within a period of time. 38) Remaining service life calculation, only with the consideration of corrosions results and remaining wall thickness often can go wrong, why? When problems are experienced with external loading, faulty material or fabrication, etc also shall be taken in to consideration when you are establishing the remaining service life and interval of inspection. 39) If the service conditions of a vessel are changed, What is to be done, before reusing the vessel in the new service condition? The maximum operating pressure, the maximum and minimum operating temperature and the period of operation until the next inspection shall be established for the new service condition. 40) If the owner ship and service conditions of a vessel are changed, what is to be done, before reusing the vessel in the new service condition? The vessel shall be both internally and externally inspected, before it is reused, and the allowable conditions of service and the next period of inspection shall be established for the new service. 41) What is the test or inspection frequency, on pressure relieving devices in typical process service? API /2004

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API /QUEST/RAJI/MARMUL API 510 Question and answers. It should not exceed 5 years, unless documented experience or disk assessment indicates that a longer interval is acceptable. For clean no fouling non corrosive services maximum intervals may be increased to 10 years. On the same way any service is found with heavy fouling or stuck in the past inspection or test may be considered and the service interval shall be reduced. 42) What are the two type’s records, which the pressure vessel owners and users shall maintain? They should maintain permanent and progressive reports. 43) What are the items which should be covered in the permanent records? Construction and design information’s, Equipment serial no name plate details etc manufactures data reports and design calculations and construction drawings. 44) Does all the repair and alteration work must be authorised by the pressure vessel inspector? Yes 45) Does all the alteration work must be authorised by the pressure vessel inspector? No, Authorisation for alterations to pressure vessels that comply with section VIII Division 1 and 2 of the ASME code, and repair to comply with ASME SECVII Div 2 shall not be authorised by the pressure vessel inspector, A Engineer Experience in pressure vessel design has been consulted, and it shall be approved by them. 46) What type of repair on pressure vessel can be authorised by an authorised pressure vessel inspector? What is the main role of the autherised pressure vessel inspector for repairing the pressure vessel built as per ASME SEC VIII DIV 1 & DIV 2? The authorised pressure vessel inspector will designate the fabrication approvals that are required. The authorised pressure vessel inspector may give prior general authorization, for limited or routine repairs as long as the inspector is sure that the repairs are the kind that will not require pressure test. And the authorised inspector shall inspect and approve all the repair and alteration work. 48) Which type of defect repair shall be referred to the pressure vessel Engineer? Repairing a crack or a discontinuity, where stress concentration may be serious should not be attempted with out prior consultation with a pressure vessel engineer experience in pressure vessel design. 50) Does the pressure vessel inspector can give authorization for a crack repair? Yes, if the crack or discontinuity is not in the area of stress concentration, then he can give authorization for a crack repair and it can be repaired by cutting a V or U shaped groove to the full length of the crack and filling the groove with weld metal deposited in accordance with applicable requirement of ASME code. 51) Is welding over pitting is permitted as per API 510? Yes refer sec 7.1.3 Corroded areas can be restored as defined by 5.7, Surface irregularities and contaminations shall be removed before welding. All repair and alterations welding shall be in accordance with ASME code. 52) What are the procedure requirement and welder’s requirement as per API 510? All the procedure qualification requirement and welder qualification requirement shall be as shall be as per ASME SEC 1X. 53) What is the alternative method to avoid PWHT as per API 510 Sec 7.2.3? Preheat or controlled deposition welding is the alternative to the post weld heat treatment, And before accepting the alternative method , the pressure vessel engineer to be consulted and a metallurgical review to be conducted., The welding method shall be as per sec 7.2.3.1 (preheating method) and 7.2.3.2 (Controlled deposition welding method.), 54) Which are the steels, which required post weld heat treatments after repair? The steels other than that specified in API 510 SEC 7.2.3.1 P No 1 , group no1,2 & 3 & P No 3 group 1 and 2 excluding Mn- Mo steels in group 2, & As per SEC 7.2.3.2 , P NO 1, PNO 3 & PNO 4 steels.

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API /QUEST/RAJI/MARMUL API 510 Question and answers. 55) If you are using the control deposition welding method, what type of testing is required for the same as per API 510? Notch toughness testing is required. AS PER SAME SEC VIII DIV 1 UG -84 and UCS 66. 56) As per API 510 , Do the post weld heat treatment application shall be reviewed and the procedure shall be developed by the authorised inspector or not? No this work shall be done by pressure vessel Engineers 57) What shall be done, before carrying out the repairs to stainless steel weld over lay and cladding? The repair procedures to restore removed, corroded, or missing clad or overlay area shall be reviewed and endorsed prior to implementation by the pressure vessel engineer and the same shall be authorised by the inspector. 58) What is the limit for carbon content as per API 510, when you are selecting the material for pressure vessel repair and what shall be the material specification? When, we are selecting the material, the new material specification shall be same as the original material or it shall be compactable to original material, the alloy steel with carbon content over 0.35 % shall not be used for the welding. 59) What is the pressure test correction formula for temperature as per API 510? Test pressure = 1.3XMAWP (

Allowable stress at test temperature

Allowable stress at design temperature 60) Do a pressure vessel inspector or pressure vessel engineer is allowed grand non destructive examination as a substitute for pressure test as per API 510? If both pressure vessel engineer and inspector is consulted and agreed by them, we can substitute the non-destructive examination as a substitute for pressure test 61) What shall be the minimum, filler metal requirement as per API 510? The filler metal used for weld repair should have minimum specified tensile strength equal to or greater than or the minimum specified tensile strength of the base material. 62) What is the non destructive examination requirement for the repair and alterations as per API -510? Prior to welding, the area prepared for welding shall be examined by either the magnetic particle or dye penetrant method to confirm the defect free surface. After the completion of the welding, it shall be examined again by either of the above method. In addition the welds in pressure vessel that was originally required to be radiographed by the rules of the original code of construction shall be radio-graphically examined. 63) What is the Individual certification validity of an authorised pressure vessel as per API 510? 3 years from the date of Issuance. At least 20% time shall be consumed for pressure vessel inspection, or minimum 75 pressure vessel inspections in 3 years time. For the eligibility for re-certification. 64) What is the re-certification, validity after the 1st Issue? 6 years 65) Which are the authorised inspection agencies? A) The inspection organization of the jurisdiction, in which the pressure vessel is used. B) The inspection organisation of the insurance company. That is licensed or registered to write the insurance and actually does write the pressure insurance. C) The inspection Organization of an owner or user for pressure vessel, who maintains an inspection organization. for his equipment only, and not for vessel indented for sale. D) An independent organization or individual, that is under contract to and under the direction of an owner user. The owner’s user shall provide the controls that are necessary,

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API /QUEST/RAJI/MARMUL API 510 Question and answers.

66) What is a repair organisation as per API-510? a) The holder of a valid ASME certificate of authorization that authorises the use of an appropriate ASME code symbol stamp. b) The owner or user of a pressure vessel, who repairs his or her own equipment in accordance with this inspection code. c) The contractor whose qualifications are acceptable to the pressure vessel owner or user and who makes repairs in accordance with this inspection code. d) An individual or organisation that is authorised by the legal jurisdiction. 67) What is the main requirement of a pressure relief valve maintenance organization? They must be experience in the valve maintenance and each valve maintenance organisation should have fully documented quality control system. 68) What is the major thing to be checked during defect inspections? The vessel shall be checked for visual indication of distortion, if its there and assess the same and check that , it is within the tolerance .all the NDT methods can be used depends upon the material, surface condition, type of repair, type of weld , and access etc. 69) If the original design conditions are not known, what shall be the material specification and joint efficiency? Consider the material as SA 283 Grd-C, & joint efficiency factor as 0.7 or refer ASME SEC VIII UG 10 C. 70) What must be the requirement for the remaining corrosion allowance, when calculating the remaining service life. The remaining thickness of any part of the vessel shall be enough to meat the calculations of design, stress, wind load, etc, the calculation shall be made after reducing two times of the require corrosion allowance, from the measured thickness.

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