ndt

Note: The source of the technical material in this volume is the ProfessionalEngineering Development Program (PEDP) of Engineering Services.

Warning: The material contained in this document was developed for SaudiAramco and is intended for the exclusive use of Saudi Aramco’semployees. Any material contained in this document which is notalready in the public domain may not be copied, reproduced, sold, given,or disclosed to third parties, or otherwise used in whole, or in part,without the written permission of the Vice President, EngineeringServices, Saudi Aramco.

Chapter : Inspection For additional information on this subject, contactFile Reference: COE10901 J.L. Mckissack on 874-2514

Engineering EncyclopediaSaudi Aramco DeskTop Standards

Introduction To Nondestructive Testing

Engineering Encyclopedia Inspection

Introduction to Nondestructive Testing

Saudi Aramco DeskTop Standards

CONTENTS PAGES

NONDESTRUCTIVE TESTING: PURPOSE, ADVANTAGES, ANDIMPORTANCE........................................................................................................... 1

Purpose............................................................................................................ 1

Advantages ...................................................................................................... 2

Importance....................................................................................................... 2

IDENTIFYING SIGNIFICANT BASE METAL AND WELD METALDISCONTINUITIES................................................................................................... 3

Base Metal Discontinuities .............................................................................. 3

Inherent ................................................................................................ 3

Primary Process ................................................................................... 4

Secondary Process ............................................................................... 4

Weld Metal Discontinuities ............................................................................. 5

Nonrelevant Indications ..................................................................... 10

Defects ............................................................................................... 10

IDENTIFYING THE CODES, STANDARDS, PROCEDURES, ANDINSTRUCTIONS ASSOCIATED WITH NONDESTRUCTIVETESTING AT SAUDI ARAMCO ............................................................................ 12

Purpose of Standards..................................................................................... 12

American National Standards Institute (ANSI).................................. 12

American Society of Mechanical Engineers (ASME) ....................... 12

American Society for Nondestructive Testing (ASNT) ..................... 14

American Welding Society (AWS).................................................... 14

American Petroleum Institute (API) .................................................. 14

Saudi Aramco Inspection Procedures (SAIPs) .................................. 15

Saudi Aramco General Instructions (SAGIs)..................................... 15



Saudi Aramco DeskTop Standards

LOCATING NONDESTRUCTIVE TESTING REQUIREMENTS ANDACCEPTANCE CRITERIA FOR WELDMENTS................................................... 17

Power Piping ................................................................................................. 17

Chemical Piping ............................................................................................ 18

Liquid Petroleum and Anhydrous Ammonia Piping ..................................... 18

Gas Transmission Piping............................................................................... 18

Power Boilers ................................................................................................ 18

Heating Boilers.............................................................................................. 18

Pressure Vessels ............................................................................................ 19

Buildings and Structures................................................................................ 19

Large Low Pressure Storage Tanks ............................................................... 19

Above Ground Atmospheric Storage Tanks.................................................. 20

Drilling Platforms.......................................................................................... 20



Saudi Aramco DeskTop Standards 1

NONDESTRUCTIVE TESTING: PURPOSE, ADVANTAGES, AND IMPORTANCE

Purpose

The purpose of nondestructive testing (NDT) is to prevent the premature failure ofcomponents or weldments and to improve the reliability and the safety of production andmaintenance operations at Saudi Aramco. NDT is used during fabrication and construction,as well as maintenance repair activities, to check and to monitor the condition of equipmentthat is used in all aspects of oil extraction and refining.

NDT is an important tool that allows the user to find potential problems that could result in anunexpected failure of piping, vessels, or other components during normal operation. When aproblem is found, it can be fixed before a situation develops that could result in personnelinjury, equipment or production loss, or damage to the environment. Saudi Aramco is fullycommitted to improve the quality, reliability, and safety of production and maintenanceoperations at their many facilities.

The role of the Engineer who is responsible for the design, maintenance, or operation ofmechanical systems is to recognize when NDT can be used and should be used to ensure or toimprove the safety, quality, and reliability of Saudi Aramco facilities and equipment.Performance of this role requires Engineers to have knowledge of the benefits of NDT and ofthe requirements for NDT. The requirements for NDT have been established for specificcomponents and systems, and these requirements are based on years of experience andempirical data. Engineers should use this past experience and the new developments in NDTtechnology to check for and to eliminate material conditions that have caused problems in thepast.

The following examples are of how NDT can be used in mechanical inspection processes toimprove quality, reliability, and safety:

• To check the integrity of pipelines or vessels that contain flammable or toxicsubstances.

• To determine the effects of erosion and corrosion on pipelines, components,and storage tanks.

• To identify cracks or weak areas that result from cyclic stresses during normalor severe service conditions.

• To observe operating characteristics of equipment or systems.




Advantages

NDT improves reliability through the detection of potential problems that could result inpremature system or component failures. Nondestructive tests are performed before the firstinstallation, after repairs, and at regularly scheduled intervals throughout the life of criticalcomponents. The continuous performance of NDT at regularly scheduled intervals providesan added level of confidence in the continued reliability of the component or system on whichthe NDT is performed.

Because components that are tested through use of NDT are not destroyed and can still beused after they are tested, NDT is more cost effective than any type of destructive testing.Defects that are identified through use of NDT during the fabrication of a system cost less torepair than defects that must be repaired in the field after the system is operational.

The capability of NDT to identify discontinuities has also led to an increase in the initialquality of fabrications and repairs. When a person who fabricates or repairs a component isaware that the fabrication or the repair will be subjected to NDT, that person is more likely tocorrectly perform the fabrication or repair because he knows that the NDT will identify anydiscontinuities.

Importance

NDT can be an extremely effective tool to inspect and to examine systems and components;however, a solid understanding of the principles of the various NDT methods is required toproperly use NDT. By understanding the basic principles of the various NDT methods, anEngineer will be able to determine the most appropriate NDT method for a given testscenario. Not all of the NDT methods are equally effective. Some NDT methods are onlycapable of surface examinations; other NDT methods can examine the entire volume of weldsor components. Some NDT methods cannot be used on nonferrous materials, and still othermethods are not conducive to extremely corroded or rough surfaces. Module COE 109.02will provide more information on the capabilities and the limitations of the various NDTmethods.




IDENTIFYING SIGNIFICANT BASE METAL AND WELD METALDISCONTINUITIES

Refer to the Introduction for Lesson 14 in the Supplemental Text, “ASNT Manual.” Thesetwo paragraphs describe the relationship between discontinuity and a defect in reference toNDT. Discontinuities can be further classified as either base metal or weld metaldiscontinuities. The geometry of the indication determines whether the discontinuity isdescribed as a linear indication or a rounded indication.

Base Metal Discontinuities

A discontinuity is an interruption of the typical structure of a material such as a lack ofhomogeneity in the mechanical, metallurgical, or physical characteristics of the material orweldment. Base metal discontinuities are classified in accord with the point in themanufacturing process in which such discontinuities occur. These discontinuities areclassified as follows:

• Inherent

• Primary Process

• Secondary Process

Inherent

Inherent discontinuities result from the original melt, casting, or solidification of the ingot ofprimary metal or alloy. The following examples of inherent discontinuities can be found inthe ASNT Manual:

• Figure 14:2, which is on page 14:4 of the ASNT manual, shows an example ofa stringer.

• Figure 14:3, which is on page 14:5 of the ASNT manual, shows an example ofa seam.

• Figure 14:4, which is on page 14:5 of the ASNT manual, shows an example ofa lamination.

• Figure 14:5, which is on page 14.5 of the ASNT manual, shows an example ofa pipe.




Primary Process

Primary process discontinuities are formed during the rough shaping and forming of metalsduring primary processing such as forging, casting, rolling and drawing. The followingexamples of primary process discontinuities can be found in the ASNT Manual:

• Figure 14:6, which is on page 14:6 of the ASNT manual, shows and exampleof a forging lap.

• Figure 14:7, which is on page 14:6 of the ASNT manual, shows and exampleof a forging burst.

• Figure 14:8, which is on page 14:7 of the ASNT manual, shows and exampleof flaking.

• Figure 14:9, which is on page 14:7 of the ASNT manual, shows and exampleof a cold shut.

• Figure 14:10, which is on page 14:8 of the ASNT manual, shows and exampleof a shrinkage crack.

• Figure 14:11, which is on page 14:8 of the ASNT manual, shows and exampleof a seam.

Secondary Process

Secondary process discontinuities are associated with final finishing operations such asmachining and heat treatments. The following examples of secondary process discontinuitiescan be found in the ASNT Manual:

• Figure 14:12, which is on page 14:8 of the ASNT manual, shows an exampleof a heat crack.

• Figure 14:13, which is on page 14:9 of the ASNT manual, shows an exampleof a quench crack.

• Figure 14:14, which is on page 14:9 of the ASNT manual, shows an exampleof a grinding crack.

For more information on each class of base metal discontinuity, refer to pages 14:4 through14:9 of the supplemental text, “ASNT Manual.”




Weld Metal Discontinuities

This section describes the typical weld metal discontinuities that are encountered in SaudiAramco systems and components. For more information on welding discontinuities, refer topages 14-10 through 14-12 of the supplemental text, “ASNT Manual.”

Figure 1 shows cracks in welds. Cracks can be either longitudinal (aligned with the weldbead) or transverse (perpendicular to the weld bead) and they can occur from stresses that aredeveloped during the welding process. Cracks also can be either surface or subsurface.Cracks severely reduce the strength of a weld. Welds with cracks are not reliable. Only verysmall cracks are acceptable, and such cracks are only acceptable in non-critical applications.

Figure 1. Cracks in Welds




Figure 2 shows slag inclusions. Slag inclusions are located within a weld and they occurwhen gases, impurities, or flux contaminate a slag weld. Slag inclusions do not alwayspresent a serious problem unless they are very large or if there are many small inclusions in agiven area. Slag inclusions weaken the welds.

Figure 2. Slag Inclusions

Figure 3 shows lack of fusion. Lack of fusion generally is located at the weld metal and basemetal interface and it occurs when the molten weld metal does not completely fuse with anadjacent weld bead or with the base material. Lack of fusion will almost always be classifiedas a defect because the weld is not reliable.

Figure 3. Lack of Fusion




Figure 4 shows incomplete root penetration. Incomplete root penetration occurs when theweld metal does not completely penetrate into the root area and consume both base materials.Incomplete root penetration creates a weak area in the weldment and is unacceptable incritical applications.

Figure 4. Incomplete Root Penetration

Figure 5 shows weld undercut. Weld undercut is an area in which the actual weld is less thanthe specific contour. Undercutting results in a depression on the surface at the point at whichthe weld metal contacts the base metal. As the size of the undercut increases, the effectivecross-sectional area of the base metal is reduced and causes a decrease in the strength of thebase metal.

Figure 5. Weld Undercut




Figure 6 shows cold lap. Cold lap occurs when the weld metal freezes too quickly and doesnot fuse with the surface of the base metal. Cold lap is most typically found on the cover passat the toe of the weld.

Figure 6. Cold Lap

Figure 7 shows root concavity. Root concavity occurs in weld joints that are welded from oneside only, an example of which would be pipe. The following are typical causes of rootconcavity:

• Too much heat, which causes shrinkage.

• A root opening that is too wide.

• Insufficient deposits of weld metal.

Figure 7. Root Concavity




Figure 8 shows a crater pit. Crater pits are located on the weld bead surface and are generallyassociated with Gas Tungsten Arc Welding (GTAW). Crater pits result from the rapidbreaking of the electric arc so that the weld puddle freezes too quickly and shrinks, whichleaves a small void.

Figure 8. Crater Pit

Figure 9 shows an arc strike. Arc strikes are caused by dragging the electrode over thesurface of the base metal in an effort to initiate an arc for welding. Such strikes that arewithin the weld groove are generally acceptable as long as the arc is properly prepared and isfully consumed in the weld.

Figure 9. Arc Strike




Figure 10 shows weld porosity. Weld porosity is caused by inadequate flux or shielding gascoverage, which allows oxygen to contaminate the molten weld metal prior to solidification.The porosity can be located on the weld surface but is typically located within the weld.Moisture or other contaminants, such as oil, that are on the base metal also can vaporizeduring welding and can result in gas bubbles being trapped in the weld metal.

Figure 10. Porosity

Nonrelevant Indications

NDT can produce or reveal indications that are not caused by actual discontinuities and theseindications are known as nonrelevant indications. Examples of nonrelevant indicationsinclude scratches or water spots on radiographic film and liquid penetrant indications thatresult from the inability to adequately remove all of the surface penetrant. Such indicationscan be determined to be nonrelevant by the NDT technician based on the method of NDT, theconfiguration of the component being examined, and the appearance of the indication. Formore information on nonrelevant indications, refer to pages 14-2 and 14-3 of thesupplemental text, “ASNT Manual.”

Defects

A defect in a component or a weld is a discontinuity or flaw that would probably result in anearly failure of the component or weld. Because all discontinuities are not defects, acceptancecriteria must be established to identify which discontinuities are acceptable. Past experiencehas helped to establish the criteria for an acceptable discontinuity. These criteria are knownas acceptance criteria and they can be found in the applicable fabrication and constructioncodes and standards. The discontinuities must be compared to the acceptance criteria todetermine whether they actually are defects.




For example, 1/16" of weld undercut in material that is 1" thick would not be acceptable inpiping that is covered by ASME B31.1 (reference paragraph 136.4.2), but such an undercutwould be acceptable in structural materials that are covered by AWS D1.1 (referenceparagraph 8.15.1.5). Also, 1/8" of weld reinforcement on a piping girth weld with a 3/8" wallthickness would be acceptable on an ASME B31.3 piping system; however, such a weldreinforcement would not be acceptable on an ASME B31.1 piping system with a maximumdesign temperature that is above 75oF.




IDENTIFYING THE CODES, STANDARDS, PROCEDURES, AND INSTRUCTIONSASSOCIATED WITH NONDESTRUCTIVE TESTING AT SAUDI ARAMCO

Purpose of Standards

The purpose of the standards that are associated with welding is to establish the minimumrequirements for design, materials, fabrication, inspection, and testing of welds to ensure alevel of quality and safety that is consistent with the intended service. Engineers that areinvolved with NDT must be familiar with the various Codes, standards, procedures, andinstructions that are associated with NDT. Excerpts from the Codes, standards, procedures,and instructions are contained in the Addendum.

American National Standards Institute (ANSI)

ANSI is the primary organization that is responsible for coordinating the activities of all otherstandard writing organizations. ANSI primarily reviews and certifies that the standards arecorrect. ANSI has established specific guidelines for the formation of other standard bodiessuch as ASME and AWS. Recently, several ANSI piping standards (B31.1, B31.3, B31.4 andB31.8) have been reclassified as ASME documents.

American Society of Mechanical Engineers (ASME)

ASME Codes are among the most widely used in the petrochemical industry and they governitems such as pressure vessels, boilers, and piping. The following is a list of the ASMECodes that will be referenced during this course:

• ASME Code B31.1

• ASME Code B31.3

• ASME Code B31.4

• ASME Code B31.8

• ASME Boiler and Pressure Vessel Code, Section I

• ASME Boiler and Pressure Vessel Code, Section IV

• ASME Boiler and Pressure Vessel Code, Section V

• ASME Boiler and Pressure Vessel Code, Section VIII




ASME Code B31.1 - Power Piping, pertains to the design, materials, fabrication, test, andinspection of power and auxiliary piping. Typical systems at Saudi Aramco include steam,water, gas, oil, and air services that support electric power generation. Refer to pages A1through A8 of the Addendum for a more detailed explanation of the scope of ASME CodeB31.1.

ASME Code B31.3 - Chemical Plant and Petroleum Refinery Piping, pertains to the design,materials, fabrication, test, and inspection of chemical piping systems. Typical applicationsinclude on-plot stripping steam, crude oil, acid, caustic, sour water, and cooling systems thatare used to refine petroleum products. Refer to pages A14 and A15 of the Addendum for amore detailed explanation of the scope of ASME Code B31.3.

ASME Code B31.4 - Liquid Transportation Systems for Hydrocarbons, Liquid PetroleumGas, Anhydrous Ammonia, and Alcohols, pertains to the design, construction, inspection,testing, operation, and maintenance of liquid petroleum and anhydrous ammonia pipingsystems. Typical applications include off-shore and off-plot cross-country pipelines,terminals, and tank farms. Refer to pages A39 and A40 of the Addendum for a more detailedexplanation of the scope of ASME Code B31.3.

ASME Code B31.8 - Gas Transmission and Distribution Piping Systems, pertains to thedesign, fabrication, installation, inspection, testing, and operation of gas transmission anddistribution systems (including gas pipelines), gas compressor stations, and gas metering andregulating stations. Refer to pages A51 and A52 of the Addendum for a more detailedexplanation of the scope of ASME Code B31.8.

ASME Boiler and Pressure Vessel Code, Section I - Power Boilers, pertains to the design,material selection, fabrication, inspection, testing, and certification of power boilers thatexceed 15 psi for steam service and that exceed 160 psi and/or 250oF for hot water service.Refer to page A60 of the Addendum for a more detailed explanation of the scope of ASMESection I.

ASME Boiler and Pressure Vessel Code, Section IV - Heating Boilers, pertains to thedesign, material selection, fabrication, inspection, testing, and certification of heating boilersthat do not exceed 15 psi for steam service or that do not exceed 160 psi and 250oF for hotwater service. Refer to page A67 of the Addendum for a more detailed explanation of thescope of ASME Section IV.

ASME Boiler and Pressure Vessel Code, Section V - Nondestructive Examination, providesrequirements and methods for NDT that include radiographic, ultrasonic, liquid penetrant,magnetic particle, eddy current, visual examination, leak testing, and acoustic emission.Refer to page A74 of the Addendum for a more detailed explanation of the scope of ASMESection V.




ASME Boiler and Pressure Vessel Code, Section VIII - Pressure Vessels, pertains to thedesign, material selection, fabrication, inspection, testing, and certification of pressure vessels.The three classes of pressure vessels that are covered by this code are welded, forged, andbrazed. Typical applications include steam generators, heat exchangers, hydrocrackers,fractionation towers, reformer reactors, and other components that are designed to containfluids or vapors at high temperatures and pressures. Refer to pages A77 and A78 of theAddendum for a more detailed explanation of the scope of ASME Section VIII.

American Society for Nondestructive Testing (ASNT)

ASNT is an organization that is dedicated to NDT. ASNT organizes and distributes technicalinformation that is specific to NDT. For example, ASNT developed the manual that is usedas the supplemental text for this course.

ASNT SNT-TC-1A - Recommended Practice for Personnel Qualification and Certification inNondestructive Testing, provides requirements for the qualification and certification of NDTpersonnel.

American Welding Society (AWS)

The AWS is an organization that provides standards for the welded fabrication of structuresand bridges with structural steel and sheet metal. For the purpose of this course, only AWSD1.1, the Structural Welding Code, will be referenced.

AWS D1.1 - Structural Welding Code, provides acceptance standards and weldingrequirements for buildings, bridges, and tubular structures. The requirements for thequalification of weld procedures and welders also are included in this Code. Typicalapplications include structural steel for catwalks, landings, and buildings.

American Petroleum Institute (API)

The API establishes guidelines that are specific to the petroleum industry’s equipment andproducts. This course will only reference the following API Codes:

• API 510

• API 620

• API 650

• API RP-2A




API 510 - Pressure Vessel Inspection Code, provides requirements for the maintenanceinspection, repair, alteration, and rerating procedures for pressure vessels that are used by thepetroleum and chemical process industries. Refer to page A118 of the Addendum for a moredetailed explanation of the scope of API 510.

API 620 - Design and Construction of Large, Welded, Low-Pressure Storage Tanks, pertainsto the design and construction of large, low pressure, above ground storage tanks. Typicalapplications include the storage of gases or vapors that results from refining operations. Referto page A123 of the Addendum for a more detailed explanation of the scope of API 620.

API 650 - Welded Steel Tanks for Oil Storage, provides material, design, fabrication, andtesting requirements for above ground atmospheric tanks. Typical applications include thestorage of crude and other liquid petroleum products. Refer to page A130 of the Addendumfor a more detailed explanation of the scope of API 650.

API RP-2A - Recommended Practice for Planning, Designing, and Constructing Fixed Off-Shore Platforms, provides a guide for the design and construction of drilling platforms. Referto page A139 of the Addendum for a more detailed explanation of the scope of API RP-2A.

Saudi Aramco Inspection Procedures (SAIPs)

Saudi Aramco has two procedures that are important to the proper performance of NDT.These SAIPs have been developed in accordance with industry Codes and Standards.

SAIP-04-P - Liquid Penetrant Examination of Welds and Components, is used by SaudiAramco personnel in the performance of liquid penetrant examinations to define the minimumrequirements and to establish applicable acceptance criteria. Refer to page A144 of theAddendum for a more detailed explanation of the scope of SAIP-04-P.

SAIP-05-P - Magnetic Particle Examination of Welds and Components, is used by SaudiAramco personnel in the performance of magnetic particle examinations to define theminimum requirements and to establish applicable acceptance criteria. Refer to page A167 ofthe Addendum for a more detailed explanation of the scope of SAIP-05-P.

Saudi Aramco General Instructions (SAGIs)

Saudi Aramco has two instructions that are important to the proper performance of NDT.These SAGIs have been developed in accordance with industry codes and standards.

SAGI 448.001 - Qualification and Certification of Nondestructive Examination Personnel, isthe instruction that establishes the procedures and defines the requirements for thequalification and certification of Saudi Aramco NDT personnel. Refer to page A198 of theAddendum for a more detailed explanation of the scope of SAGI 448.001.




SAGI 448.010 - Radiographic Examination, is used by Saudi Aramco personnel in theperformance of radiographic testing to determine the minimum requirements and to establishapplicable acceptance criteria. Refer to page A218 of the Addendum for a more detailedexplanation of the scope of SAGI 448.010.




LOCATING NONDESTRUCTIVE TESTING REQUIREMENTS AND ACCEPTANCECRITERIA FOR WELDMENTS

This portion of the Module identifies the section of the applicable codes, standards,procedures, and instructions that contain the NDT requirements and acceptance criteria for thefollowing types of weldments:

• Power Piping

• Chemical Piping

• Liquid Petroleum and Anhydrous Ammonia Piping

• Gas Transmission Piping

• Power Boilers

• Heating Boilers

• Pressure Vessels

• Buildings and Structures

• Large Low Pressure Storage Tanks

• Above Ground Atmospheric Storage Tanks

• Drilling Platforms

Power Piping

The NDT requirements for power piping welds are described in ASME B31.1, Chapter VI,Table 136.4. Table 136.4 is located on page A11 of the Addendum. Table 136.4 shows thevarious NDT requirements for pressure welds or for welds to pressure retaining componentsbased on piping service conditions. Table 136.4 shows that the specific requirements forNDT depend on the design temperature and pressure ratings of a given system.

The weld acceptance criteria is located in paragraph 136.4 of ASME B31.1. Paragraph 136.4is located on page A9 of the Addendum.




Chemical Piping

The NDT requirements for chemical piping welds are described in ASME B31.3, Chapter VI,paragraph 341.4. Paragraph 341.4 is located on page A28 of the Addendum. Table 341.3.2Aof ASME B31.3 shows the acceptance criteria for welds and it is based on the applicableservice conditions. Table 341.3.2A is located on page A26 of the Addendum. Anunderstanding of the service condition (normal fluid, severe cyclic, or category D) is criticalto determining the appropriate NDT requirements.

Liquid Petroleum and Anhydrous Ammonia Piping

The NDT requirements for liquid petroleum and anhydrous ammonia piping welds aredescribed in ASME B31.4, paragraph 434.8.5. Paragraph 434.8.5 is located on page A46 ofthe Addendum. Additional requirements for inspection and testing are described in ChapterVI. Chapter VI is located on pages A47 and A48 of the Addendum.

Gas Transmission Piping

The NDT requirements for gas transmission piping welds are described in ASME B31.8,Chapter II, paragraph 826. Paragraph 826 is located on page A57 of the Addendum.Knowledge of the weld location class is required to properly determine the NDTrequirements.

Power Boilers

The NDT requirements for the fabrication of power boilers are described in ASME Section I,Part PW. Paragraphs PW-11 and PW-41 address NDT requirements that are based oncomponent diameter, wall thickness, and component exposure to radiant heat or furnacegases. Paragraph PW-11 is located on page A62 of the Addendum and paragraph PW-41 islocated on page A63 of the Addendum.

The weld acceptance criteria is provided in paragraphs PW-51 and PW-52 of ASME SectionI. Paragraph PW-51 is located on page A65 of the Addendum and paragraph PW-52 islocated on page A66 of the Addendum.

Heating Boilers

ASME Section IV does not require specific NDT beyond a visual examination. The weldacceptance criteria is provided in paragraph HW-820 of ASME Section IV. Paragraph HW-820 is located on page A71 of the Addendum.




Pressure Vessels

The NDT requirements for pressure vessel welds are described in ASME Section VIII,Division 1, paragraph UW-11. Paragraph UW-11 is located on page A84 of the Addendum.The NDT requirements may be based on the type of weld, the weld category, or the diameteror the thickness of the weld. The weld acceptance criteria is provided in paragraph UW-51 ofASME Section VIII. Paragraph UW-51 is located on page A85 of the Addendum.

Buildings and Structures

The NDT requirements for structural welds that are in statically loaded buildings andstructures are described in AWS D1.1, paragraphs 6.7 and 8.15. Paragraph 6.7 is located onpage A113 of the Addendum and paragraph 8.15 is located on page A114 of the Addendum.The weld acceptance criteria for VT is located in paragraph A.15.1 of AWS D1.1. Paragraph8.15.1 is located on page A114 of the Addendum. The weld acceptance criteria for RT islocated in paragraph 8.15.3 of AWS D1.1. Paragraph 8.15.3 is located on page A114 of theAddendum. The weld acceptance criteria for PT and HT is located in paragraph 8.15.5 ofAWS D1.1. Paragraph 8.15.5 is located on page A115 of the Addendum.

Large Low Pressure Storage Tanks

The NDT requirements for welds that are in large low pressure storage tanks are described inAPI 620, Section 5. Section 5 is located on pages A125 through A129 of the Addendum.Information that is related to the type and orientation of the weld, as well as to the basematerial thickness, is required to determine the NDT requirements.

The acceptance criteria requirements for HT and PT are respectively located in paragraphs5.20.4 and 5.22.4 of API 620, Section 5. These paragraphs reference ASME Section VIII,Appendices 6 and 8 for the actual acceptance criteria. Appendix 6 is located on pages A104and A105 of the Addendum, and Appendix 8 is located on pages A109 and A110 of theAddendum.

The acceptance criteria requirements for VT are located in paragraph 5.21.1 of API 620,Section 5. These requirements must be agreed to by the purchaser and the manufacturer.

The acceptance criteria requirements for RT are located in paragraph 5.15.4 of API 620,Section 5. This paragraph references ASME Section VIII, paragraph UW-51(b) for the actualacceptance criteria. Paragraph UW-51(b) is located on page A86 of the Addendum.

The acceptance criteria for VT is located in paragraph 5.19 of API 620, Section 5.




Above Ground Atmospheric Storage Tanks

The NDT requirements for welds that are in above ground atmospheric storage tanks aredescribed in API 650, Section 5. Section 5 is located on pages A132 through A134 of theAddendum. Information that is related to the type and orientation of the weld, as well as to thebase material thickness, is required to determine the NDT requirements.

The acceptance criteria requirements for RT are located in paragraph 6.1.5 of API 620. Thisparagraph references ASME Section VIII, paragraph UW-51(b) for the actual acceptancecriteria. Paragraph 6.1.5 is located on page A137 of the Addendum and paragraph UW-51(b)is located on page A86 of the Addendum.

The acceptance criteria requirements for HT and PT respectively are located in paragraphs6.2.4 and 6.4.4 of API 620. These paragraphs reference ASME Section VIII, Appendices 6and 8 for the actual acceptance criteria. Paragraphs 6.2.4 and 6.4.4 of API 620 are located onpage A138 of the Addendum. Appendix 6 of ASME Section VIII is located on pages A104and A105 of the Addendum, and Appendix 8 of ASME Section VIII is located on pages A109and A110 of the Addendum.

The acceptance criteria requirements for UT are located in paragraph 6.3.4 of API 620. Theserequirements must be agreed upon by the purchaser and the manufacturer. Paragraph 6.3.4 islocated on page A138 of the Addendum.

Drilling Platforms

NDT requirements for drilling platforms are described in API RP-2A, Section 13. Section 13is located on pages A141 through A143 of the Addendum. The Weld acceptance criteria islocated in paragraph 13.4.3b of API RP-2A, Section 13. This paragraph references AWSD1.1 for the actual acceptance criteria. AWS D1.1 is located on pages A113 through A117 ofthe Addendum. Paragraph 13.4.3b of API RP-2A also states that the acceptance criteria forother NDT methods must be defined in the specifications.

ndt

Documents

purpose of standards

nondestructive testing

nondestructive testing

weld metal discontinuities

base metal discontinuities

american welding society

significant base metal

technical material