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20.1 INTRODUCTION The purpose of this chapter is to provide
users of the ASME
Boiler and Pressure Vessel Code Section V [1] an insight into
thesignificant Section V requirements, NDE methods, and
NDEmethodology, as well as the relation of Section V to other
ASMEbook sections and to the use of the American Society for
TestingMaterials (ASTM) Standards [2]. The information provided
inthis chapter is based on the 2007 edition of Section V with
2007addenda, dated July 1, 2007.
The charter and scope for the Subcommittee for Section V(SCV) is
to develop and maintain Code rules for NDE methodolo-gy and
equipment involved in surface and volumetric testingmethods. These
test methods are used for the detection and sizingof defects,
discontinuities, and flaws in materials and weldmentsduring the
manufacture, fabrication, and construction of parts,components, and
vessels in accordance with the ASME Boilerand Pressure Vessel Code
and other ASME Codes; for example,B31.1 for Power Piping [3].
SCV members consist of representatives from
manufacturers,insurance companies, architectural engineering
companies,research organizations, utilities, consulting firms, and
the NationalBoard of Boiler and Pressure Vessel Inspectors. All
additions,revisions, inquires, and Code Cases relating to Section V
arereviewed and approved by the SCV before being presented to
theMain Committee for review and approval for adoption.
20.2 ORGANIZATION OF SECTION V It is important for users to
become familiar with the organiza-
tion of Section V. The book is divided into two basic
subsections.Subsection A of Section V contains Articles 1 through
17, includ-ing Mandatory and Nonmandatory appendices that address
generalrequirements, test methods, and specific Code
requirements.Subsection B of Section V contains the ASTM Standards
(Articles22 through 31) that have been adopted by the Code.
Following Subsections A and B is Mandatory Appendix I,
whichprovides guidance and directions for the Mandatory Submittal
of
Technical Inquiries to the Boiler and Pressure Vessel
Committeeand is therefore of utmost importance to users. Before
submittingan inquiry to SCV, users should carefully consider their
specificproblem and select the proper category from the following
listing inthis Mandatory Appendix:
(1) a proposed revision to present Code rule(s); (2) a new or
additional Code rule(s); (3) a Code Case; and (4) a Code
Interpretation. The SCV receives many inquries that do not provide
the
required details. Unfortunately, this lack of specificity only
delaysthe review process. Inquiries that request a Code
Interpretationmust be composed as brief and precise questions that
can beanswered by a simple yes or no. On occasion, requests forCode
Interpretations are submitted after the fact. In other words,
adisagreement on interpretation of a requirement has
occurredbetween the parties involved long after the work or
examination(s)has been completed. Obviously, the SCV reply is not
going tofavor one of the parties. It is therefore of utmost
importance toresolve, if at all possible, any differences before
work progressesbeyond the point of no return. For example, the
radiographictechnique and completed radiographs should be reviewed
by allparties involved as soon as possible upon the completion
ofsuch work. It is too late to submit a request for a
CodeInterpretation after the component or vessel has been
completedand is sitting, waiting to be Code-stamped and accepted by
allparties involved.
20.2.1 Essential and Nonessential Variables Resulting from a
request by the ASME Post Construction Code
Standards Committee, Subcommittee V established essential
vari-ables for demonstrating performance capabilities to qualify
proce-dures. While the request was specific to the ultrasonic
examina-tion method, the Subcommittee decided to proactively
defineessential variables for all NDE methods in Section V. The
formatultimately selected was based on the essential/nonessential
vari-able format used by Section IX. Please note: Essential
variable vs.
NONDESTRUCTIVEEXAMINATION (NDE)
Jon E. Batey1
1Harold C. Graber was the author for the first edition of this
chaptereditor
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nonessential variable is only important when procedure
qualifica-tion is required by a referencing code. Otherwise, the
combinedlists of essential and nonessential variables simply
represent itemsrequired to be described in a written procedure.
20.3 RELATION TO OTHER ASMECODE BOOK SECTIONS
As previously mentioned, Section V primarily addresses thetest
methods and methodology for NDE. Other ASME Code sec-tions, such as
I, III, VIII, and XI [4][7], include specific method-ology
requirements and provide acceptance criteria for the testmethods
referenced. To ensure that all contract requirements aresatisfied,
users must understand the relationship of Section V tothe Codes
other sections. As an example, let us step through therequirements
that must be satisfied when the contract specifies forthe component
or vessel to be built in accordance with ASMECode Section I, 2007
edition with 2007 addenda [4].
First, we must look in Section I and determine the
requirementsfor NDE. In Section I, we find paragraph PW-11 to be
pertinent,as it is called Radiographic and Ultrasonic Examination
ofWelded Butt Joints. Selecting the radiographic requirement,
wefind that Table PW-11 requires all longitudinal and
circumferen-tial butt-welded joints to be radiographically examined
through-out their entire length in accordance with Section V
Article 2 andalso meet the requirements of paragraph PW-51, with
someexceptions. Assuming now that radiography for a
butt-weldedjoint is required, we must look at the requirements of
paragraphPW-51, which is titled Acceptance Standards for
Radiography.The text of subparagraph PW-51.1 states that welds
shall beexamined throughout their entire length by the x-ray or
gamma-ray method in accordance with Section VArticle 2, except
thatthe requirements in Article 2, paragraph T-274
(GeometricUnsharpness) are to be used as a guide rather than for
the rejec-tion of radiographs unless the geometrical unsharpness
exceeds0.07 inch. Subparagraph PW-51.2 states that a single-welded
cir-cumferential butt joint with a backing strip may be
radiographedwith the backing strip intact, provided the backing
strip is not tobe subsequently removed and its image does not
interfere with theinterpretation of the radiographs. This is an
example of where aCode section provides technical requirements that
differ from therequirements of Section V.
Next, let us look at the requirements for personnel
qualification(PQ). Again, Section I, paragraph PW-50.1 provides
requirementsfor PQ that states the manufacturer shall certify that
personnelperforming and evaluating radio-graphic examinations
requiredby Section I have been qualified and certified in
accordance withtheir employers written practice. The American
Society forNondestructive Testing (ASNT) [8] documents SNT-TC-1A
[9] orCP-189 [10] shall be used as a guideline for employers to
estab-lish their written practice. Provisions for training,
experience,qualification, and certification shall be provided and
described inthe manufacturers quality control system. PW-50.2
requires PQby examination, including the certification of NDE Level
III per-sonnel beginning with the 2004 Edition of Section I with
2004Addenda. Paragraph PW-50.3 addresses how personnel
recertifi-cation is handled. This is important information to
users, for theapplicable edition of the ASNT document depends on
the specificedition of the Code and is provided in Section I, Table
A-360. Forexample, Table A-360 of the 2007 edition of Section I
with 2007addenda specifies SNT-TC-1A (2001) as the applicable
edition.
Another significant requirement of Section I is acceptance
cri-teria. Paragraphs PW-51.3, PW-51.3.1, PW-51.3.2, PW-51.3.3,and
PW-51.3.4 provide the acceptance criteria for imperfections(a term
defined in Section V, Article 1, Mandatory Appendix I,Glossary of
Terms, paragraph I-130). Paragraph PW-51.3.4addresses rounded
indications, and the size, frequency, and dis-tribution are
provided in detailed charts located in Appendix A-250. A typical
example is as shown in Fig. 20.1. The chartsprovide graphic
illustrations of random, isolated, and cluster dis-tributions, as
well as aligned indications. Charts are provided forweld
thicknesses of in., inclusive; over in., inclusive;over in.,
inclusive; over in., inclusive; over 24 in.,inclusive; and over 4
in.
Section I, paragraph PW-51.4 provides requirements for
reten-tion of completed radiographs. The current requirement (i.e.,
the2007 edition with 2007 addenda) is that a complete set of
radi-ographs for each job shall be retained by the manufacturer
andkept on file for a period of 5 yr.
This overview provides an insight into the interrelationships
ofthe Code sections. Section I was selected as an example for
sim-plicity; however, users should be cautioned that other Code
sec-tions for example, Section III [5] or Section XI [7]provide
manymore complex requirements and significant changes to
therequirements of Section V.
It is important to remember that contract requirements shouldbe
reviewed and the applicable edition of the Code determinedbefore
production is started. This information should then be pro-vided to
all personnel involved to ensure that manufacturingplans, tests,
and nondestructive examinations are performed inaccordance with the
correct requirements of the applicable Codeedition. Making certain
that the correct information is available atthe start will prevent
subsequent delays caused by the discoveryof a noncompliance for
work performed to the wrong Code edi-tion or wrong addenda. Any
noncompliance could very well resultin an inquiry to the Code
Committee, who cannot always resolvethe inquiries in a timely
fashion.
20.4 ARTICLE 1: GENERALREQUIREMENTS
Section V, Article 1 addresses general requirements that
areunique and applicable in most cases to the other articles.
Thescope of this article provides important information about
theinterface of Section V with other Code sections or documents.
Ofsignificance is the statement: This section of the Code
containsrequirements and methods for nondestructive examination
(NDE),which are Code requirements to the extent they are
specificallyreferenced and required by other Code sections or
referencingdocument. The text also states that the test methods are
intendedto detect surface and internal discontinuities in
materials, welds,and fabricated parts and components.
The paragraph titled General provides an explanation
ofSubsections A and B. Subsection A describes the test methods tobe
used. When reference is made to a paragraph belonging to anarticle
in Subsection A or to some other Code section, all of
thatparagraphs rules are applicable. For example, reference to
para-graph T-270 (Examination) includes all the rules in
subparagraphsT-271 through T-277.3. Subsection B lists documents
and stan-dards adopted by Section V, which are intended to be used
forinformation purposes and are nonmandatory unless
specificallyreferenced in whole or part by the articles under
Subsection A or
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other Code sections. It is important to note that a reference
madeto a standard is only mandatory to the extent specified in the
arti-cle or other Code section. In essence, this means that an
articlemay only reference a specific paragraph in an ASTM
Standard[2]; therefore, only the referenced paragraph becomes a
Coderequirement, and the remainder of the standards requirements
donot apply.
The paragraph titled General also addresses personnel
quali-fication and certification (PQ). This paragraph is probably
one ofthe most significant in Subsection A because of the various
alter-natives for meeting PQ requirements. For instance, let us
take alook at the current requirements in Article 1. The first
documentreferenced is the 2001 edition of SNT-TC-1A,
PersonnelQualification and Certification in Non-destructive Testing
[9],published by the ASNT. A second document referenced is the2001
edition of ANSI/ASNT CP-189 [10], also published by theASNT. Either
one of these documents may be used for PQ, unlessrequirements to
the contrary are provided by other applicableCode sections. To
further emphasize the importance of working tothe control
requirements, note that in the 1995 edition of SectionV, Article 1,
paragraph T-140, the pertinent reference is to the1992 edition of
SNT-TC-1A, while in the 1989 edition, paragraphT-140 specifies the
use of the 1984 edition of SNT-TC-1A. Thisexample illustrates how
requirements change when later versionsof documents are adopted.
Again, users should be cautioned thatthe PQ version and edition
listed in Section V, Article 1 may notbe the same as the version
and edition listed in a previous editionof Section V or in another
Code section.
Paragraph T-120 provides additional clarifications for PQ
andshould be reviewed to ensure compliance. One last item of
signifi-cance in paragraph T-120 is that it addresses limited
certification.
T-120(i) allows an exception to the requirements of SNT-TC-1 Aor
CP-189 regarding training and experience of personnel who donot
perform all of the operations of a NDE method or whoperforms
examinations of limited scope. However, if this
limitedcertification is used, the limitations must be described in
themanufacturers written practice and listed on the
individualscertification records.
20.4.1 Paragraph T-150, Procedure This paragraph provides the
requirements for NDE technical
procedures used for the test methods in Subsection A. It
addressessituations where special configurations and materials may
requiremodified methods and techniques, in which case the
manufacturermust develop special procedures that are equivalent or
superior tothe test methods and techniques described in the
applicable arti-cle. The special procedure or technique must be
capable of pro-ducing interpretable results when one is performing
the test underthe special conditions. The procedure or technique
may be a mod-ification or combination of methods described in the
article.Depending on the quality system used and as required by the
ref-erencing Code section, the special procedure shall be submitted
tothe Authorized Inspector (AI) for acceptance and then adopted
aspart of the manufacturers quaity control program.
Paragraph T-150(c) specifically states when required by a
ref-erencing Code section, all nondestructive examinations
performedunder this Code section shall be done to a written
procedure. Italso requires the procedure to be demonstrated to the
satisfactionof the AI. When required, written procedures must be
made avail-able to the Inspector on request. At least one copy of
the writtenprocedure shall be readily available to the
manufacturers nonde-structive examination personnel for their
reference and use.
FIG. 20.1 CHARTS FOR T 1-1 IN., INCLUSIVE (Source: Fig. 3.1,
Section I of the ASME B&PV Code)
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20.4.2 Paragraph T-160, Calibration This paragraph is important
in that it requires the manufacturer,
fabricator, or installer to ensure that all calibrations of
equipmentare performed in accordance with the applicable articles
inSubsections A or B. It also provides requirements addressing
theuse of special procedures and stipulates that the
manufacturer,fabricator, or installer is responsible for specifying
what calibra-tions are necessary and the calibration frequency.
20.4.3 Paragraph T-170, Examinationsand Inspections
This paragraph defines the term Inspector and the
Inspectorsduties and authority. Furthermore, it establishes the
distinctionbetween the terms inspection and examination. The user
isadvised to read this paragraph in its entirety to understand the
dis-tinctions of the variety of terms used.
20.4.4 Paragraph T-180, Evaluation This paragraph simply informs
the user of the fact that Section
V does not provide acceptance criteria for the test methods
listedin the articles and that one must refer to the referencing
Code sec-tion for this information.
20.4.5 Paragraph T-190, Records Records and documentation must
be maintained by the manu-
facturer, fabricator, or installer in accordance with the
applicablerequirements of Subsections A or B and the referencing
Codesection.
20.4.6 Mandatory Appendix I, Glossary of Terms This important
appendix provides the standard terminology for
NDE. The ASTM Standard E-1316, Standard Terminology
forNondestructive Examination, has been adopted as SE-1316 and
islocated in Article 30. This standard provides terminology for
allNDE methods. However, Mandatory Appendix I in addition pro-vides
specific Code terms that either do not appear in E-1316 orare terms
whose definitions have been changed to satisfy theCode. Users of
Section V should be familiar with the terms inMandatory Appendix I
and, in particular, with the definitions fordefect, discontinuity,
evaluation, false indication, flaw, flaw char-acterization,
imperfection, interpretation, nonrelevant indication,and relevant
indication. All of these terms are used by the variousCode sections
and in their acceptance criteria. It is very importantto understand
the terms and their associated definitions whenmaking
acceptance-rejection decisions.
20.4.7 Article 1, Nonmandatory Appendix A Article 1,
Nonmandatory Appendix A adds Table A-110, provided
here as Table 20.1, listing common imperfections vs. the type
ofNDE methods that are generally capable of finding
them.Nonmandatory Appendix A was developed for people with a
limitedbackground in NDE, not for experienced NDE personnel. Users
areencouraged to read the cautionary statement in A-110 plus the
notesto Table A-110. Specifically, Table A-110 must not be used as
a basisfor requiring nor for prohibiting a particular type of NDE
method.
20.5 ARTICLE 2: RADIOGRAPHICEXAMINATION
Article 2 covers the radiographic test method used for
theexamination of materials, including castings and welds.
Included
in the article are eight Mandatory Appendices (I-VII) and
threeNonmandatory Appendices (A, C, and D). The MandatoryAppendices
are the following:
Appendix I, In-Motion Radiography. Appendix II, Real Time
Radioscopic Examination. Appendix III, Digital Image Acquisition,
Display, and
Storage for Radiography and Radioscopy. Appendix IV,
Interpretation, Evaluation, and Disposition of
Radiographic and Radioscopic Examination Test ResultsProduced by
the Digital Image Acquisition and DisplayProcess.
Appendix V, Glossary of Terms for Radiographic Examination.
Appendix VI, Digital Image Acquisition, Display,
Interpretation, and Storage of Radiographs for
NuclearApplications.
Appendix VII, Radiographic Examination of Metallic Castings.
Appendix VIII, Radiography Using phosphor Imaging Plate.
Users should be aware that before the 1998 edition of SectionV,
Radiographic Examination of Castings was covered in Article3. The
1998 edition of Section V now covers RadiographicExamination of
Metallic Castings in Mandatory Appendix VII.When using an appendix,
the requirements as stated in the appen-dix apply as well as the
requirements of the article; therefore,users should be cautioned to
consider this when using a specialtest technique in the applicable
appendix.
The Nonmandatory Appendices (A, C, and D) are as follows: (A)
Recommended Radiographic Technique Sketches for Pipe
or Tube Welds. Techniques used for examination of pipeand welds
are illustrated, providing guidance for varioustypical technique
setups.
(C) Hole-Type IQI Placement Sketches for Welds. Figures
thatillustrate typical hole-type IQI placement for welds
areprovided. Not being all-inclusive, they do not cover
allapplications of production radiography; however, they doprovide
a wide range of technique applications and serveas a tutorial.
(D) Number of IQIs (Special Cases). Figures that
illustrateexamples of the required number and placement of IQIsused
for special cases are provided. Paragraph T-277.2describes the
requirements for special cases, and the figuresprovide pictorial
illustrations of IQI placements for typicalconfigurations.
Not all paragraphs in Article 2 will be addressed here, but
onlythose of special significance.
20.5.1 Paragraph 210 Scope This paragraph covers the scope of
the article. Note the require-
ment that this article shall be used together with Article 1.
Thissimply means that the general requirements provided in Article
1also apply unless stated otherwise or are modified by other
Codesections or reference documents. The scope also specifies that
theapplicable definitions for terms used in the article are those
pro-vided in Mandatory Appendix V.
20.5.2 Paragraph T-220 General Requirements Paragraph T-220
covers the general requirements of the article,
including some very significant requirements that must be
careful-ly addressed by users. The first item concerns procedure
and is
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therefore of great importance. In fact, for good practice
regardless ofwhether a Code section requires a procedure, it is
always advisableto prepare a written procedure covering all of the
items listed in theparagraph. The procedure serves several
purposes. Foremost, it pro-vides the necessary guidance for the
radiographer to properly per-form radiography or radioscopy during
production and later helpsthe radiographic interpreter prepare the
required documentation.Whether a procedure is obligatory depends on
the requirements stat-ed in the pertinent Code sections. As an
example of where a writtenprocedure is required, Section III,
Division 1, Subsection NB,Article NB-5000, paragraph NB-5112 states
the following: Allnondestructive examinations required by this
Article shall be per-formed in accordance with detailed written
procedures which havebeen proven by actual demonstration to the
satisfaction of theInspector [5]. Procedure demonstration and
compliance to the writ-ten procedure is satisfied by assuring the
required density and properimages appear on the production or
technique radiographs.
20.5.3 Paragraph T-222, Surface Preparation Surface preparation
is probably one of the most subjective and
difficult requirements to deal with satisfactorily for all
partiesinvolved. The requirement addresses both materials
(includingcastings) and welds. The basic requirement for materials
is thatthe surface being examined must satisfy the applicable
MaterialSpecification or referencing Code section. Additional
surface con-ditioning by manual or mechanical processing may be
required toassure that surface irregularities are removed to the
extent theycannot mask or be confused with any discontinuity image
on theradiograph. For welds, the requirement is the same, but with
theadditional requirements that weld ripples or weld surface
irregu-larities on both sides of the weld (where accessible) shall
be pre-pared. This is where the subjectivity comes in. To what
extentmust the surface be prepared to ensure that any remaining
surfaceirregularity images cannot mask or be confused with images
of adiscontinuity? For example, in most cases as-welded
surfaceswhere the weld ripples or valleys between beads are slight
andessentially smooth, these irregularities will not appear as
imageson the radiograph because of their subtlety. However, if the
weldripples or valleys between beads are extreme, they will appear
assignificant light/dark images on the radiograph. Depending on
theheight of the ripples and the depth of the valley between
beads,the density of the images of these irregularities will be
pro-nounced on the radiograph. If disagreements between
partiesoccur regarding whether the surface irregularities can mask
a dis-continuity, one common way to resolve the impasse is to
preparethe surface of a worst-case condition until the
irregularities areremoved entirely. If images appear upon
reradiography of theselected area, then obviously a subsurface
discontinuity is presentand requires disposition. Remember the time
to resolve any dif-ferences is as soon as possible after completing
the radiography.This promptness serves two purposes: (1) it
provides the inter-preters with an opportunity to visually observe
the questionablearea(s), and (2) it allows for any additional
surface conditioning tobe preformed to confirm the presence of
unacceptable discontinu-ities and in some cases before the area
becomes inaccessible.
20.5.4 Paragraph T-226, Extent of Examination The requirement is
that the extent of examination shall be as
specified by the referencing Code section. Again, it is
importantto be familiar with Code section and contract
requirements. Forexample, Section VIII, Division 1, paragraph UW-52
providesrules for spot examination of welded joints [6].
20.5.5 Paragraph T-230, Equipment and Materials Subparagraph
T-231.2 addresses film processing and references
two ASTM Standards [2] adopted by the Code: SE-999 and SE-94,
both of which are located in Article 22. It is important to
note,however, that these two standards are to be used as guides
and, assuch, are not mandatory.
Subparagraph T-233 covers IQI Design. The ASTM StandardsE-1025
and E-747 provide IQI design requirements that havebeen adopted by
the Code as SE-1025 and SE-747 and shall befollowed in their
entirety except that the largest wire number orthe wire identity
number may be omitted. (SE-1025 and SE-747standards are also found
in Article 22.) An example of the hole-type IQI Design is shown in
Fig. 20.2. Tables T-233.1 (given hereas Table 20.2) and T-233.2
(given here as Table 20.3) provide alisting of ASME Standard IQIs
for hole and wire-type IQIs. Table20.2 provides the hole-type IQI
designation, thickness, and 1T,2T, and 4T hole diameters. It should
be noted that this table is forstandard IQIs, but if the situation
warrants, nonstandard IQIs maybe used. Table 20.3 provides the four
sets of wire IQIs and theassociated wire sizes in each set.
20.5.6 Paragraph T-260, Calibration This paragraph is important
because users are required to provide
documented evidence of the physical size of x-ray and
gamma-raysources. This is another requirement that is vulnerable to
audit.
T-262 (Step Wedge Film and Densitometer) covers calibration
ofthe densitometer. A calibrated step wedge film traceable to a
nation-al standard is also required. Documentation of the
authenticity of thecalibrated step wedge film should be maintained
and kept on file.
20.5.7 Paragraph T-270, Examination Paragraph T-271 covers the
requirements for single-wall and
double-wall radiographic techniques. It should be noted that
thedouble-wall radiographic technique where the radiation
passesthrough two walls and the material or weld in both walls is
viewedfor acceptance is limited to materials and welds 3 in. (89
mm) orless in nominal outside diameter. Other restrictions for
number ofexposures and radiation beam offset are also included.
Nonmandatory Appendix A provides illustrations of techniquesused
for the examination of pipe and tube welds. Again,
theseillustrations are not mandatory, but provide excellent
detailedinformation for establishing the proper technique.
Paragraph T-272 covers radiation energy.
Paragraph T-274 covers geometric unsharpness
limitations.Geometric unsharpness is directly related to the
physical size of agamma-ray source or the focal spot of an x-ray
machine. Thesmaller, the better and the closer the radiation source
can be inrelation to the film. This paragraph provides the maximum
geo-metric unsharpness permitted for various material thicknesses.
Itshould be noted that the referencing Code section, excludes
ormodifies this requirement in some cases. Geometric
unsharpness(Ug) values can be calculated in accordance with the
formula Ug= Fd/D, provided in this paragraph.
Paragraph T-275 covers location marker requirements both
forsingle-wall and double-wall viewing and for using a map
wheninaccessibility or other limitations prevent placement of
markersas required. Figure T-275 provides location marker sketches
forvarious typical configurations and radiation source
locations.
Paragraph T-276, on IQI selection, is important and must
becarefully addressed. One must ensure that the IQI selected is
forthe nominal single-wall thickness of the object, part, or
compo-nents being radiographed. Table T-276 (given here as Table
20.4)
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FIG. 20.2 IQI DESIGN (Source: Fig.1, Article 22, Section V of
the ASME B&PV Code)
provides the IQI required for single-wall material with
thicknessesup to 20 in. The table also provides the hole-type IQI
designation,and if a wire IQI is used, the required wire to be
imaged. TheseIQI requirements are provided for both source-side and
film-sideIQI placement.
Paragraph T-276 also provides requirements for IQI selection
forwelds with reinforcements and without reinforcements. For
weldswith reinforcements, it is important to note that IQI
selection isbased on the nominal single-wall thickness plus the
estimated weld
reinforcement, not to exceed the maximum permitted by the
refer-encing Code section. For welds without reinforcement, the IQI
isbased on the nominal single-wall thickness, and backing rings
orstraps are not considered part of the weld thickness.
Radiographicpersonnel should be very familiar with these
requirements; notethat for welds with reinforcement, the estimated
reinforcement (i.e.,it does not have to be physically measured) is
considered whendetermining the total thickness upon which the IQI
is based. One isreminded that the maximum reinforcement allowed
cannot be
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exceeded. If the reinforcement is close to the maximum, then
obvi-ously one must physically measure it to ensure that the
maximum isnot being violated. Paragraph T-276 also covers IQI
requirementsfor dissimilar metal welds joining dissimilar base
materials.
Paragraph T-277 covers the use of IQIs and the specific
place-ment and number of IQIs. Film-side IQIs are permitted for
those
cases where inaccessiblity prevents hand-placing the IQI on
thesource side. For example, a pipe weld is radiographed using
anisotope placed on the I.D. of the pipe, and because the weld
areacannot be reached physically by hand, it is permissible to use
afilm-side IQI in this case. Paragraph T-277.2 provides
require-ments and Nonmandatory Appendix D provides guidance
anddirection for placement of IQIs for special applications.
20.5.8 Paragraph T-280, Evaluation This paragraph covers several
important requirements.
Paragraph T-281, Quality of Radiographs, addresses
requirementsfor the quality of the completed radiographic film. If
proper careand controls are not used in film handling and
processing, filmartifacts will occur and, if severe, can mask or be
confused withthe image of a discontinuity.
Paragraph T-282, Radiographic Density, is important and mustbe
carefully followed because it provides the required values forfilm
density. Users should remember that a densitometer is usedto
measure film density and density strips or step wedge compar-ison
film are used to estimate or judge film density. In caseswhere an
absolute value must be determined, the only way tomake the
measurement is by using a densitometer.
Paragraph T-285 covers evaluation. After the radiograph(s)
havebeen completed, it is the manufacturers responsibility to
ensurethat the radiographs have been reviewed, interpreted,
properly eval-uated, and accepted in accordance with the
requirements of Article2 and, when applicable, the referencing Code
section. A copy of thedetails of the radiographic technique and the
radiographic reviewform documentation that shall accompany the
radiographs.
20.5.9 Paragraph T-290, Documentation An old cliche is that the
work is not done until the paperwork
is completed. Paragraph T-291 requires the manufacturer to
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prepare and document the details of the radiographic
technique,including some specifically required information. The
detailslisted are minimums, and it is good practice to include
otherspecifics, such as IQI designation and IQI material, shims
andshim thickness, and so forth. It is also important to note
thatacceptance of the radiographs by the manufacturer or the
manu-facturers authorized representative must be completed
beforepresenting the radiographs and documentation to the
Inspector.Paragraph T-292, Radiographic Review Form, states that
themanufacturer is required to prepare a radiographic reivew
form;this document provides details of the evaluation of the
complet-ed radiograph(s).
20.6 ARTICLE 4: ULTRASONICEXAMINATION METHODS FOR WELDS
Article 4 describes and references requirements for
ultrasonicexamination of welds. When performing an examination in
accor-dance with any part of the article that is a requirement of a
refer-encing Code section, that referencing Code section shall
beaddressed for specific requirements for the following:
PersonnelQualification/Certification, Procedure and/or Technique
require-ments, Examination System Characteristics, Retention
andControl of Calibration Blocks, Acceptance Standards, Reportsand
Records Retention requirements, Extent of Examinationand/or volume
to be scanned. Users of the article should carefullyreview the
requirements to ensure that all are satisfied. Therequirements are
established for the detection of reflectors in theweld,
heat-affected zone, and adjacent base material. Two
generalexamination classifications have been established: welds in
ferrit-ic product forms other than pipe, and ferritic welds in
ferriticpipe. For austentic and high-nickel alloy welds,
examination isusually more difficult because of wide variations in
the materialproperties even in alloys of the same composition,
product form,and heat treatment. Therefore, because of these
difficulties, it maybe necessary to modify and/or supplement the
provisions of
Article 4 and establish special technique(s), as permitted
inArticle 1 paragraph T-150(a).
20.6.1 General Requirements Consistent with the other articles
in SCV, Article 4 also activates
Article 1 by stating that when Article 4 is specified by a
referencingCode section, the ultrasonic method described in Article
4 shall beused together with Article 1 (General Requirements).
Definitions ofterms are provided in Mandatory Appendix III of
Article 5.
20.6.2 Written Procedure Requirements The examination shall be
performed in accordance with a writ-
ten procedure, and the procedure shall include the following
listof information, as applicable:
Weld configurations to be examined, including
thicknessdimensions, and base material product form (casting,
plate,bar, tube, forging, and so forth).
The surface(s) from which the examination will be performed.
Surface condition (examination surface, calibration block).
Couplant brand and type. Technique (straight beam, angle beam,
contact, or immersion). Angles and mode(s) of wave propagation.
Search unit type, size, and frequency. Special search unit wedges,
shoes, or saddles. Instrument type. Description of calibration
block. Directions and extent of scanning. Records and calibration
data to be recorded, and the method
of recording (manual or computer enhanced). Description of
automatic alarm and recording equipment (if
used). Scanning (manual vs. automatic). Scan overlap. Computer
enhanced data acquisition (when used). Method for discriminating
geometric vs. flaw indications. Method for sizing indications.
Personnel qualification requirements.
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FIG. 20.3 NON-PIPING CALIBRATION BLOCKS (Source: Fig.T-434.2.1,
Section V of the ASME B&PV Code)
20.6.3 Equipment and Supplies
20.6.3.1 Instrument The examination shall be performed witha
pulse-echo instrument capable of generating frequencies over
therange of 15 MHz. An instrument may be operated at a
differentfrequency, provided equal or better sensitivity is
demonstrated anddocumented.
20.6.3.2 Search Units and Contact Wedges Search units usedto
perform the examination shall meet the following criteria:
Search units may have either single or dual transducer
elements.
Contoured contact wedges connected to the search unit maybe used
to aid in coupling to the part contour or for soundtransmission
(e.g., angle beam mode or transmit receiveapplications). If contact
wedges are used, they shall be inplace when performing
calibration.
20.6.3.3 Basic Calibration Block Requirements The basic
cali-bration block configuration and calibration hole locations
shall be asshown in Fig. T-434.2.1 (given here as Fig. 20.3). The
material fromwhich the block is fabricated shall be of the same
product form andhaving the same Material Specification or
equivalent P-number
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grouping as one of the materials being examined. P-numbers 1, 3,
4,and 5 are considered equivalent. Calibration block material for
dis-similar metal welds shall be based on the material on the side
of theweld where the examination is performed. If the examination
is per-formed from both sides of the weld, two calibration blocks
arerequired, and the calibration block thickness shall be based on
theaverage thickness of the weld. When the component material is
cov-ered with overlay cladding, the calibration block shall also be
cladas well by using the same welding procedure that was used on
theproduction part. If the production clad was performed by an
auto-matic welding process, and it is impractical to perform
automaticwelding on the calibration block, the block may be clad by
using amanual process. It is recommended that consideration be
given tousing dropouts or prolongations for the calibration blocks
that havebeen welded by the production process before their removal
fromthe production part. The calibration block shall receive at
least theminimum tempering treatment required by the
MaterialSpecification for the type and grade, and also a postweld
heat treat-ment if the block contains weld(s) other than cladding.
The surfacefinish of the calibration block shall be representative
of the surfacefinish on the production component(s). The
calibration block mate-rial shall be examined 100% using straight
beam. Areas of the blockthat contain reflectors providing an
indication exceeding the backreflection shall be excluded from the
sound path required to obtain asignal from the various calibration
reflector(s).
20.6.3.4 Piping Calibration Block Requirements The
basiccalibration block as shown in Fig. 20.4 (Fig. 434.3) shall be
used.
20.6.3.4.1 Examination of Welds in Materials withDiameters
Greater than 20 In. (508 mm) If the examinationmaterial surface is
greater than 20 in. in diameter, a calibration blockof essentially
the same curvature is desired or, alternatively, a flatcalibration
block may be used. As an alternative, when performing
the examination from a convex surface using the straight
beamtechnique, Appendix G may be used.
20.6.3.4.2 Examination of Welds in Materials withDiameters Less
than 20 In. (508 mm) If the examination mater-ial surface is less
than 20 in. in diameter, a curved calibration blockis required. A
single curved block may be used to examine sur-faces in the range
of curvature 0.91.5 times the basic calibrationblock diameter.
20.6.4 Calibration
20.6.4.1 Screen Height Linearity The instrument shall providea
linear vertical presentation within 5% of the full screen heightfor
20100% of the calibrated screen height (baseline to
maximumcalibrated screen point or points). A procedure for
determining andevaluating screen height linearity is provided in
MandatoryAppendix I. The screen height linearity shall be performed
at thebeginning of each period of extended use (or every 3 mo. for
ana-log instruments and 1yr for digital instruments, whichever is
less).Users should pay close attention to maintaining the
instrumentscreen height linearity within the limits to ensure
accurate flawdetection and sizing.
20.6.4.2 Amplitude Control Linearity The instrument shalluse an
amplitude control that is accurate over its useful range to20% of
the nominal amplitude ratio. The amplitude controlaccuracy is
important for measuring indications beyond the linearrange of the
vertical display on the CRT screen. A procedure fordetermining and
evaluating amplitude control linearity is providedin Mandatory
Appendix II. Determination of amplitude controllinearity shall be
performed at the beginning of each period ofextended use (or every
3 mo. for analog instruments and 1yr fordigital instruments,
whichever is less). Again, users should pay
;
FIG. 20.4 CALIBRATION BLOCK FOR PIPE (Source: Fig.T-434-3,
Section V of the ASME B&PV Code)
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12 Chapter 20
close attention to maintaining the amplitude control linearity
with-in the limits to ensure proper measurement of indications
beyondthe linear range of the vertical display on the CRT
screen.
20.6.4.3 Checking and Calibration of Equipment Proper
func-tioning of the examination equipment shall be checked and
theequipment calibrated by using the required calibration
standard(s)at the beginning and end of each examination (when
personnel arechanged) and anytime a malfunction is suspected. These
requisitesare established as minimums, so users are reminded to pay
closeattention to ensuring that examination equipment is
functioningproperly at all times. For this reason, periodic
calibration verifica-tions over the course of the work shift are
strongly recommended,particularly when the examination extends over
long time periodssuch as several days or longer. If during any of
the checks theequipment is discovered to be functioning improperly,
all of thework performed since the last acceptable verification
checkrequires reexamination. Again, the importance of verifying
calibra-tion cannot be overemphasized, for such verification can
save timeby preventing the need for performing a reexamination.
20.6.4.4 System Calibration Calibration shall include the
com-plete system used to perform the production examination.
Eachcalibration shall be performed from the surface (clad or
unclad) ofthe calibration block corresponding to the surface of the
compo-nent being examined. Appendices B and C of Article 4
providegeneral techniques for both angle beam and straight beam
calibra-tion. Other techniques may be used.
20.6.4.5 Angle Beam Calibration As applicable, the calibra-tion
shall include the following requirements in addition to thegeneral
requirements specified in Article 4, Appendix B:
(1) distance-range calibration; (2) distance-amplitude
correction; (3) echo amplitude measurement from the surface notch
in the
basic calibration block.
When an electronic distance-amplitude correction device isused,
the primary reference responses from the basic calibrationblock
shall be equalized over the distance range to be used for
theproduction examination. The response equalization line shall be
at4080% of full screen height.
20.6.4.6 Straight Beam Calibration The straight beam
calibra-tion requirements are the same as those described for angle
beamcalibration, except that echo amplitude measurement is
notapplicable.
20.6.4.7 Calibration Check Using the Basic Calibration Blockor
Simulator If any part of the examination system is changed,
acalibration verification check shall be performed by using the
basiccalibration block to verify that /T, /2T, and /T points on the
sweepand distance amplitude correction values previously recorded
sat-isfy the initial calibration data. At the completion of each
exami-nation or series of examinations (when personnel are changed)
andevery 4 hr. during the examination, a calibration check using
atleast one of the calibration reflectors in the basic calibration
blockor simulator shall be performed. The sweep and distance
ampli-tude correction values recorded shall satisfy the straight
beam cal-ibration verification. When a simulator is used, the
checks shall becorrelated with the data obtained during original
calibration on thebasic calibration block. A simulator may be, for
example, an IIW
34
12
14
block or electronic simulation. The simulation used shall be
com-pletely identifiable on the calibration sheet(s). The accuracy
of thesimulator checks shall be confirmed by using the basic
calibrationblock at the conclusion of each period of extended use
or every 3 mo., whichever is less. The requirements for calibration
confir-mation shall be met.
Calibration confirmation is not satisfied for sweep-range
cor-rection if a point on the DAC has moved on the sweep line
bymore than 10% of the sweep reading or 5% of the full
sweep,whichever is greater. One must then correct the sweep-range
cali-bration and note the correction on the examination records.
Ifreflectors are recorded on the data sheets, those data sheets
shallbe voided and the new calibration recorded. All recorded
indica-tions since the last valid calibration or calibration check
shall bereexamined with the corrected calibration and their values
record-ed on the data sheets. Calibration confirmation is not
satisfied forDAC correction if a point on the DAC curve has
decreased 20%or 2 db. In such a case, all data sheets since the
last valid calibra-tion or calibration check shall be marked void.
A new calibrationshall be performed and recorded, the area covered
by the voideddata shall be reexamined, and previously recorded
indications val-ues shall be changed and recorded on the data
sheets.
20.6.5 Examination
20.6.5.1 Examination Coverage The volume shall be examinedby
moving the search unit over the examination surface to scan
theentire volume. To ensure complete coverage, each pass of
thesearch unit shall be overlapped a minimum of 10% of the
transduc-er element dimension perpendicular to the direction of the
scan.
20.6.5.2 Rate of Search Unit Movement The rate of the searchunit
movement shall not exceed 6 in./sec. unless calibration is
ver-ified or confirmed at the scanning speed used.
20.6.5.3 Surface Preparation The base metal on the side(s) ofthe
weld from which the examination will be performed shall befree from
weld spatter and foreign matter, and surface irregulari-ties shall
be removed by mechanical means to the extent that suchremoval does
not interfere with the examination. The weld surfaceshall also be
free from weld spatter and foreign matter, and wheresurface
irregularities interfere with the examination, the surfaceshall be
prepared to the extent necessary for the irregularities notto
interfere.
20.6.5.4 Scanning Requirements The base material adjacent tothe
weld that will be involved in the examination shall be scannedusing
the straight beam technique to detect any base metal reflec-tors
that may interfere with the angle beam test results. The loca-tions
of the reflectors shall be recorded for reference purposes onlyand
shall not be evaluated in accordance with the acceptance crite-ria
for the weld.
Angle beam scanning for reflectors oriented parallel to theweld
shall be performed with the angle beam directed approxi-mately at
right angles to the weld axis from two directions (wherepossible).
The search unit shall be manipulated so that the soundbeam passes
through the required volume of weld to be examined.Scanning shall
also be performed at a gain setting of at least twotimes the
primary reference level; however, evaluation of reflec-tors shall
be performed at the primary reference level.
Angle beam scanning for reflectors oriented transverse to
theweld shall be performed with the angle beam directed
essentially
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parallel with the weld. The search unit shall be manipulated
sothat the sound beam passes through the required volume of weldto
be examined. Scanning shall be performed at a gain setting ofat
least two times the primary reference level; however, evaluationof
reflectors shall be performed at the primary reference level.The
search unit shall be rotated 180 deg. and the
examinationrepeated.
20.6.5.5 Cladding The following requirements apply only
toweld-metal-overlay cladding and when examination is required
bythe referencing Code section. Test requirements for roll bond
orexplosive clad plate shall be performed in accordance withSA-578,
located in Article 23. Two examination techniques areprovided for
weld-metal-overlay cladding: the first is for lack ofbond and clad
defects, the second for lack of bond only.
20.6.5.5.1 Equipment, Calibration Block, Calibration,
andExamination Requirements for Technique 1 Dual search unitsset up
for pitch catch shall be used. The included angle betweenthe two
beam paths shall be such that maximum sensitivity of thesearch unit
is in the area of interest. The calibration block shownin Fig.
T-434.4.1 (given here as Fig. 20.5) shall be used. The blockshall
be clad using the same weld process as was used for theproduction
part. The surface condition shall be equivalent to theproduction
part. Either a in. (1.6 mm) diameter in. longside-drilled hole
located at the clad interface or a in. (3.2 mm)flat-bottom hole
drilled through the base material and terminatingat the clad
interface may be used. The thickness of the blocks base
18
* 112116
material shall be at least two times the thickness of the
cladding.The examination shall be performed from the clad surface,
and theentire clad surface shall be examined where practical. The
exami-nation shall be performed with the plane separating the
elementsof the two search units placed parallel to the axis of the
weldbead(s). Scanning shall be performed at two times the primary
ref-erence level and by moving the search unit perpendicular to
theweld direction. All indications shall be evaluated at the
primaryreference level.
20.6.5.5.2 Equipment Calibration Block, Calibration,
andExamination Requirements for Technique 2 Straight beamsearch
units shall be used. A cladded calibration block is requiredusing
the same welding process as used in production, with thesurface
condition representative of the production part is used. A in. (10
mm) flat-bottom hole is drilled through the base
material,terminating at the claddingweld-metal interface. The
thickness ofthe base material shall be at least twice the thickness
of the weld-overlay cladding. Calibration shall be performed by
placing thesearch unit on the calibration block opposite from the
drilled hole.The search unit shall be manipulated to obtain a
maximumresponse from the calibration hole, and the gain shall be
set so thatthis response is 80% (5%) of full screen height. This is
the pri-mary reference level. Scanning shall be performed at a gain
settingat least two times the primary reference level, and scanning
shallbe performed on the clad surface if calibration is performed
fromthe clad surface. All indications shall be evaluated at the
primaryreference level.
38
FIG. 20.5 CALIBRATION BLOCK FOR TECHNIQUE 1 (Source:
Fig.T-434.4.1, Article 4, Section V of the ASME B&PV Code)
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14 Chapter 20
20.6.6 Evaluation Any imperfection that causes an amplitude
response in excess
of 20% DAC (or 40% of the rejectable flaw size for
non-distanceamplitude techniques) shall be investigated to the
extent that itcan be evaluated in terms of the acceptance criteria
required bythe referenced Code section.
20.6.7 Reports and Records A report of the examination is
required. The report shall include
a record (which may be a marked-up sketch) indicating the
volumeexamined. The report shall also include the location of
eachrecorded reflector and identify the operator who performed
(partlyor entirely) the examination. Instrument calibrations,
system cali-brations, and calibration block identification, as
required, shall beincluded in the calibration records. Examination
records shouldinclude the following information in addition to any
additionaldetailed information specified by the referencing Code
section:
(1) procedure identity; (2) examination equipment; (3) personnel
identity and qualification level; (4) calibration sheet identity;
(5) identification of weld or volume scanned and any inacces-
sible areas; (6) identification of surface(s) used in the
examination; (7) a map or record of indications detected or,
alternatively,
areas clear of indications; (8) the date(s) and time(s) when the
examination was per
formed; (9) type of couplant used;
(10) calibration block identification and calibration
data(including simulators, if used);
(11) surface condition; (12) frequencies and angles used; (13)
equipment used (search units, cables); and (14) a listing of any
special equipment used. Records of any evaluations of indications
shall be maintained
and documented as required by the referencing Code section.
20.6.8 Article 4, Nonmandatory Appendix L Article 4,
Nonmandatory Appendix L provides methodology
that can be used to demonstrate the ability of an ultrasonic
systemto size depth and length of indications using
time-of-flight-diffraction (TOFD). Nonmandatory Appendix L
specifically per-tains to a dual-probe, computer imaging TOFD
technique andincludes a system for classifying imperfections.
20.6.9 Article 4, Nonmandatory Appendix N Article 4,
Nonmandatory Appendix N provides useful informa-
tion that can be used as an aid for interpreting TOFD
images.
20.7 ULTRASONIC EXAMINATIONMETHODS FOR MATERIALS
Article 5 describes the methodology for ultrasonic examinationof
plate, pipe, forgings, castings, and for thickness determina-tions.
Definitions of terms used found in Mandatory Appendix IIIof this
Article. When SA, SB, and SE documents are referenced,they are
located in Article 23.
20.7.1 General Requirements When Article 5 is specified by a
referencing Code section, the
General Requirements section of Article 1 applies. Note:
Writtenprocedure requirements, equipments requirements,
maximumsearch unit movement rate, calibration requirements,
evaluationrequirements, and documentation are very similar to
thosedescribed for Article 4 in 20.6.
In general, calibration reflectors in calibration blocks
aredescribed in referenced SA, SB, and SE documents in Article22.
However, there are important exceptions located in T-534.For
example, longitudinal notches of 1 in. (25 mm) maximumlength and
1/16 in. (1.6 mm) maximum width are required forpipe examinations.
The notch depth cannot exceed 0.004 in.(0.10 mm) or 5% of the
nominal wall thickness, whichever isgreater.
20.7.2 Examination Most examination requirements are described
in the following
documents located in Article 23:
Plate-SA-435/SA-435M, SA-577/SA-577M, SA-578/SA-578M, or SB-548,
as applicable.
Forgings/Bars-SA-388/SA-388M, or SA-745/SA-745M,
asapplicable.
Tubular Products (such as Pipe)SE-213 or SE-273,
asapplicable.
CastingsSA-609/SA-609M. Bolting MaterialSA-388/SA-388M.
Thickness MeasurementSE-797. Inservice Examination of
CladdingSA578/SA-578M.
Note: This requirement excludes weld metal overlay; exami-nation
requirements for weld metal overlay are described inArticle 4,
T-473.
As mentioned previously, Article 5 amends the SA, SB, and
SEdocuments for certain requirements. In the case of
conflictingrequirements, the amended exceptions in Article 5 take
prece-dence over the requirements in the SA, SB, and SE
documents.As an example, Article 5 amends the examination
requirements ofSA-609/SA-609M for casting by stating in T-571.4(a),
Forstraight-beam examinations, the sensitivity compensation in
para-graph 8.3 of SA-609/SA-609M shall not be used.
Additional examination requirements are described in
theMandatory Appendices to Article 5 as follows:
Pumps and ValvesMandatory Appendix I. Inservice Examination of
Nozzle Inner Radius and Inner
Corner RegionMandatory Appendix II. Inservice Examination of
BoltingMandatory Appendix IV.
20.8 ARTICLE 6: LIQUID-PENETRANTEXAMINATION
Article 6 describes the methodology and technques used
forliquid-penetrant examinationone of the most frequently
usedmethods and one that is required and referenced by many of
theCode sections. When Article 6 is specified by a referencing
Codesection, the General Requirements section of Article 1 is
alsoapplicable.
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20.8.1 Procedures and Procedure Revision(s) The examination
shall be performed in accordance with a writ-
ten test procedure, and the following items should be
consideredfor inclusion in the procedure:
(1) Material shapes and sizes, and extent of examination. (2)
Type and letter or numerical designation of each penetrant,
penetrant remover, emulsifier, and developer. (3) Details for
preexamination cleaning and drying, including
the precleaning material(s) used and the minimum dryingtime.
(4) Details for the application of the penetrant, penetrant
dwelltime, and temperature of the penetrant and of the part
beingexamined (if the test is performed outside the
temperaturerange of 50125F).
(5) Details for removal of excess penetrant and drying of
thesurface before application of developer.
(6) Details for applying the developer and the developing
dwelltime before interpretation.
(7) Minimum light intensity. (8) Details for postcleaning. (9)
Personnel qualification requirements.
20.8.2 Equipment The equipment, consisting of penetrant
materials, includes all
materials used for the examination, such as penetrants,
cleaners,emulsifiers, solvents, cleaning agents, developers, and so
forth.
20.8.3 Control of Contaminants Article 6 Appendix-II provides
detailed information and
requirements for the control of contaminants, as well as the
certi-fication requirements for penetrant materials (including
preclean-ing solvents) that will be used on nickel-base alloys,
austeniticstainless steels, and titanium materials. Article 24
contains SDstandards 129, 1552, 516, 808, and SE-165, all of which
are usedfor reference for material analysis procedures. Specific
analysisrequirements are provided in Article 6 Appendix-II. Users
shouldbe aware of the necessity to obtain certifications from the
manu-facturers of penetrant materials and also to file the
certificationsfor verification during subsequent audits.
20.8.4 Surface Preparation The examination may be performed on
the part without any sur-
face conditioning, provided the surface irregularities cannot
maskindications of unacceptable discontinuities. Surface
preparation bymechanical means may be required. Article 24 contains
StandardSE-165, Annex 1, and is a reference procedure for
additional infor-mation on general precautions relating to surface
conditioning. Thisreference should be reviewed by users for
consideration in listingsurface finish requirements in the test
procedure. The test surfaceand all adjacent surfaces within 1 in.
shall be dry and free of anyextraneous materials (grease, dirt,
scale, weld flux, spatter, oil, andso forth). Degreasing or
ultrasonic cleaning methods may berequired. After cleaning, the
surface(s) shall be dried by normalevaporation or by using forced
hot or cold air. The minimum dryingtime shall be established and
specified before the penetrant applica-tion to ensure that the
cleaning solvent has completely evaporated.
20.8.5 Techniques Either a color-contrast (visible) penetrant or
a fluorescent pene-
trant shall be used with one of the following processes:
(1) water washing; (2) postemulsifying; (3) solvent removal. For
the standard technique, the temperature of the penetrant and
surface of the part being examined shall be in the range of
40F(5C)125F (52C). When it is not practical to comply with
thistemperature range, other temperatures may be used if the
procedureis both qualified and in accordance with the technique
requirementsfor nonstandard temperatures, as specified in Article
6.
20.8.6 Calibration Both visible and fluorescent light meters
shall be calibrated
annually, or whenever the meter has been repaired.
20.8.7 Examination The penetrant may be applied by any suitable
means. The pene-
trant dwell time is critical, and the dwell time shall be as
specifiedin Table 20.5 (Table T-672) or as qualified by
demonstration forspecific applications. The removal of excess
penetrant is critical,
TABLE 20.5 MINIMUM DWELL TIMES (source: Table T-672, Section V
of the ASME B&PV Code)
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16 Chapter 20
and Article 6 provides specific requirements for removal of
water-washable, postemulsifying, and solvent-remover penetrants.
Dryingof the surface after the penetrant removal can be
accomplished byblotting or by using circulating air for
water-washable or postemul-sifying penetrants; for solvent removal,
drying may be performed bynormal evaporation, blotting, wiping, or
the use of forced air.Developer application for wet or dry
developers may be performedby any suitable means. The minimum
developing time shall be asspecified in Table T-672 (given here as
Table 20.5).
20.8.8 Interpretation Final interpretation of the test results
shall be made within 1060
min. after the developing dwell-time requirement has been
satisfied.Longer periods are permitted if the bleed-out does not
alter theresults. When using color-contrast penetrant, the test
results shall beviewed under a light intensity of 100 foot-candles
(1000 Lx); forfluorescent penetrants, the test results shall be
viewed using a blacklight with an intensity of 1000 mW/sq. cm on
the surface of thepart. The black light intensity must be checked
prior to use andafter completion of examination(s), and it is good
practice to docu-ment verification of the check.
20.8.9 Evaluation All indications shall be evaluated in
accordance with the accep-
tance standards of the referencing Code section.
20.8.10 Documentation and Records Documentation and records
shall be completed in accordance
with the requirements of the referencing Code section.
20.9 ARTICLE 7: MAGNETIC-PARTICLEEXAMINATION
Article 7 describes the requirements and methodology for
theperformance of the magnetic-particle examination test
method.Magnetic-particle examination is a widely used test method
by theCode and is referenced as a requirement in many Code
sections.Article 25 contains SE-709, which is a reference standard
andshould be consulted by users when establishing their test
proce-dures. Also, when Article 7 is specified by a referencing
Code sec-tion, the requirements of Article 1 apply. In some cases,
the refer-encing Code section alters the Article 1 and Article 7
requirements;therefore, it is important to review the referencing
Code sectionrequirements when establishing the test procedure.
Article 7 hasthree Mandatory Appendices: Mandatory Appendix I
covers exam-ination of coated ferritic materials using the AC yoke
technique,Mandatory Appendix II covers the definition of terms,
andMandatory Appendix III covers examinations using the yoke
tech-nique with fluorescent particles in an undarkened area.
20.9.1 Equipment The equipment selected must be capable of
producing the nec-
essary magnetic flux in the part being examined, using the
contin-uous method and one or more of the following techniques:
prodtechnique, longitudinal and circular magnetization
techniques,yoke technique, and multidirectional technique.
20.9.2 Examination Medium Dry, wet, visible, or fluorescent
particles may be used in accor-
dance with the applicable technique selection. Article 25
containsSE-709, which provides specific requirements for all types
of
particles and should be consulted when developing the test
proce-dure. When using fluorescent particles, the examination must
beperformed using an ultraviolet light (black light), and the
exami-nation must be performed in a darkened area unless the
require-ments of Mandatory Appendix III are met.
The black light shall have an intensity of 1000 mW/sq. cm at
thesurface of the part; the light intensity shall be measured using
ablack-light meter prior to and at the completion of
examinationsplus any time the lights power supply is interrupted or
changed. Itis important to maintain records of the intensity
measurements andfrequency for subsequent audit verifications.
Pretest requirementsfor use of the black light include a warm-up
period of 5 min., andthe operator must be in the darkened area for
5 min. before startingthe examination to enable the inspectors eyes
to adapt to darkviewing. Photosensitive eyeglass lenses are not
permitted.
20.9.3 Surface Conditioning Surface conditioning is normally not
necessary, and satisfactory
results can be obtained when surfaces are, for example, in the
as-welded, as-rolled, as-forged, or as-cast condition; however,
sur-face preparation by any mechanical means may be required if
thesurface irregularities could mask indications. Before the
examina-tion, the surface to be examined and adjacent areas within
1 in.shall be cleaned by any suitable means to ensure removal of
extra-neous materials that could interfere with the examination.
InArticle 7, paragraphs T-741.1 and T-741.2 provide
additionalrequirements regarding cleaning and use of
surface-contrastenhancement coatings for enhancing particle
contrast.
20.9.4 Procedure/Technique The test procedure shall include at
the very least the following
details:
(1) materials, shapes, and sizes to be examined and the extentof
examination;
(2) magnetization technique used; (3) equipment used; (4)
surface preparation (finishing and cleaning); (5) type of particles
used; (6) magnetization current (type and amperage); (7) method of
particle application; (8) method of excess particle removal; (9)
minimum light intensity;
(10) coating thickness; (11) examination surface temperature;
(12) post examination cleaning technique; (13) demagnetization; and
(14) personnel qualification requirements.
20.9.5 Magnetic Field Adequacy and Direction A magnetic-particle
field indicator (also called a pie gage or pie
indicator), described in Fig. T-764.1.7 (given here as Fig.
20.6),may be used when it is necessary to verify the adequacy or
direc-tion of the magnetizing field. Because magnetic-particle
fieldindicator is only permitted within the limitations prescribed
forvarious magnetizing techniques, it is important to review
Article7, paragraph T-764.3 for those limitations.
20.9.6 Rectified Current Whenever direct current is required,
rectified current may be
used. The current shall be either three phase (full-wave
rectified)or single phase (half-wave rectified).
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20.9.7 Demagnetization Demagnetization is required when residual
magnetization in
the part could interfere with subsequent processing or usage.
Thedemagnetization can be performed at any time after completion
ofthe examination.
20.9.8 Calibration of Equipment Test equipment with ammeters
must be calibrated at least once
each year or whenever the equipment has been subjected to
majorrepairs or overhaul. Article 7 provides details for the
calibrationprocedure and tolerance values.
20.9.9 Lifting Power of Yokes The lifting power of yokes shall
be checked annually or if the
yoke has been damaged. AC yokes must have a lifting power of10
lb. and DC permanent yokes must have a lifting power of 40lb. at
maximum pole spacing.
20.9.10 Examination At least two separate examinations shall be
performed on each
test area. For the second examination, the lines of flux should
beapproximately perpendicular to those used for the first
examina-tion. The examinations shall be conducted with sufficient
overlapto ensure that 100% coverage is obtained. Article 7 provides
spe-cific examination details for the five techniques previously
men-tioned, and it is important to refer to the detailed
requirements forthe specific technique that will be used for the
examination.
20.9.11 Evaluation All indications shall be evaluated in
accordance with the accep-
tance criteria in the applicable referencing Code section.
20.9.12 Records An examination record is required, documenting
type of
equipment, magnetic particles, lighting equipment, and
technique
used. Additional requirements are listed in paragraph T-793.
Atechnique sketch is required only if the multidirectional
tech-nique is used. The technique-sketch requirements are listed
inparagraph T-791.
20.10 ARTICLE 8: EDDY-CURRENTEXAMINATION OF TUBULARPRODUCTS
This article covers the test method requirements for
eddy-current examination of tubular products. The methods and
techniques substantially conform to SE standard 243 found inArticle
26. SE-243 should be reviewed when developing the testprocedure.
When eddy-current examination is required by a referencing Code
section, Article 1 requirements also apply.There are six Mandatory
Appendices that accompany Article 8:Appendix I,. Glossary of Terms
for Eddy-Current Examination;Appendix II, Eddy-Current Examination
of NonferromagneticHeat Exchanger Tubing; Appendix III,
Eddy-Current Examinationon Coated Ferritic Materials; Appendix IV,
External Coil EddyCurrent Examination of Tubular Products; Appendix
V, EddyCurrent Measurement of Nonconductive-Nonmagnetic
CoatingThickness on a Nonmagnetic Metallic Material; and
AppendixVI, Eddy Current Detection and Measurement of Depth
ofSurface Discontinuities in Nonmagnetic Metals with SurfaceProbes.
Again, the applicable Mandatory Appendix requirementsshall be
followed for the specific application.
20.10.1 General All eddy-current or electromagnetic examinations
shall be per-
formed in accordance with a detailed written procedure
unlessother provisions are stated in the referencing Code
section.
20.10.2 Personnel Qualifications Personnel qualification
requirements are as specified in the ref-
erencing Code section.
20.10.3 Procedure The procedure used for the examination shall
ensure a sensitivi-
ty level at which indications equal to or greater than those
obtainedfrom the reference standard are consistently detected. The
writtenprocedure shall include at least the following
information:
(1) frequency; (2) mode; (3) minimum fill factor; (4) type of
coil or probe; (5) scanning speed and technique; (6) type of
material and size(s); (7) reference standard notch or hole size;
(8) equipment manufacturer/model; (9) scanning equipment;
(10) data recording equipment; (11) cable type and length; and
(12) software used for acquisition/analysis.
20.10.4 Reference Standard The reference standard (reference
specimen) shall be the same
as the parts being examined and processed in the same manner.The
standard shall be of the same nominal diameter and samenominal
composition as the parts being examined. Unless specifiedotherwise
by the referencing Code section, the calibration reference
FIG. 20.6 MAGNETIC-PARTICLE FIELD INDICATOR(Source: T-764.1.1,
Article 7, Section V of the
ASME B&PV Code)
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shall be transverse notches or drilled holes, as specified in
Article26, SE-243. The standard shall be long enough to simulate
thehandling of the part through the inspection system equipment.The
separation between the reference notches or drilled holesplaced in
the same reference standard should not be less thantwice the length
of the sensing unit on the inspection system.
20.10.5 Calibration The inspection system shall be checked and
verified by using
the reference standard as follows:
(1) at the beginning of each run of a given diameter and
thick-ness;
(2) at the end of the production run; and (3) anytime there is
an equipment malfunction. If at anytime during calibration or the
production run it is deter-
mined that the equipment is not functioning properly, all of
theproduct tested since the last valid calibration or verification
shallbe reinspected.
20.10.6 Evaluation Examination test results shall be evaluated
in accordance with
the requirements of the referencing Code section. As previously
mentioned, there are six Mandatory Appendices
accompanying Article 8 that address specific applications.
Usersshould be aware of these specific applications, as they may be
rel-evant to the examination being performed.
20.11 ARTICLE 9: VISUAL EXAMINATION Appendix I, which is
mandatory, accompanies Article 9 and
provides a glossary of terms. Article 9 requirements at this
time are primarily invoked by
Section III. However, because it is good manufacturing practice
toperform a visual examination to ensure product quality,
usersshould become familiar with the requirements of Article 9
andapply visual examination as they see fit.
20.11.1 Written Procedure Requirements The examination shall be
performed in accordance with a writ-
ten procedure prepared by the manufacturer. The
manufacturershall make available the procedure and a list of the
examinationsto be performed to the Authorized Inspector. The
procedure shallinclude at least the following:
(1) equipment used for remote viewing (2) equipment used for
direct viewing (3) personnel qualification requirements (4) methods
and/or tools used for surface preparation; (5) whether direct or
remote viewing will be used; (6) special illumination, instruments,
or equipment used; (7) sequence of performing the operation, when
applicable; (8) lighting intensity; (9) configuration to be
examined; Procedures may be general or specific for a certain
application.
The procedure shall contain or reference a report of the
testmethod used to demonstrate the procedures adequacy. A fine
line1/32 in. or less in width or a similar artificial flaw placed
on thesurface at the least discernible location to be examined may
beconsidered as a test method for the demonstration.
20.11.2 Physical Requirements Personnel performing visual
examination shall have an annual
vision test to ensure natural or corrected near-distance acuity.
Thetest consists of the candidate being able to read the J-1
letters onstandard Jaeger test charts. Equivalent tests may be used
in lieu ofthe Jaeger test charts.
20.11.3 Procedure/Technique
20.11.3.1 Typical Applications The following several
commonapplications of visual examination are used:
(1) to determine if surface conditions of the part satisfy the
sur-face requirements;
(2) verification of alignment of mating surfaces; (3)
verification of shapes; and (4) evidence of leaks during static or
dynamic testing. 20.11.3.2 Techniques Techniques used are direct
viewing,
remote viewing, and translucent examination. Specific
require-ments for each technique are provided in the Article.
20.11.3.3 Evaluation All examination results shall be
evaluatedin accordance with the criteria required by the
referencing Code sec-tion. An examination checklist is required to
plan the visual exami-nations and verify that visual observations
have been completed.
20.11.3.4 Documentation and Records When required by
thereferencing Code section a written report is made and shall
bemaintained as required by that referencing Code section.
Specificitems to be included in the report are listed in the
Article.
20.12 ARTICLE 10: LEAK TESTING Article 10 consists of the
general section, ten Mandatory
Appendices and one Nonmandatory Appendix. Most of
theseAppendices cover specific types of tests, as follows:
Appendix I, Bubble Test (Direct Pressure Technique). Appendix
II, Bubble Test (Vacuum Box Technique). Appendix III, Halogen Diode
Detector Probe Test. Appendix IV, Helium Mass Spectrometer
(Detector Probe
Technique). Appendix V, Helium Mass Spectrometer (Tracer
Probe
Technique). Appendix VI, Pressure Change Test. Appendix VII,
Glossary of Terms. Appendix VIII, Thermal Conductivity Detector
Probe Test. Appendix IX, Helium Mass Spectrometer (Hood Technique).
Appendix X, Ultrasonic Leak Detector Test. Appendix A, is Leak
Testing Formula Symbols.
The requirements of the applicable Mandatory Appendix mustbe
followed for the specific test technique being performed.
20.12.1 Procedure Written procedure requirements vary slightly
according to tech-
nique. In general, the procedure shall include the following
mini-mum information:
(1) extent of the examination; (2) type of equipment used for
detecting leaks or measuring
leak rates;
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(3) type of surface cleaning performed and equipment used; (4)
method or technique of the test to be performed; and (5)
temperature, pressure, gas, and % concentration to be used. The
referencing Code section shall be consulted for additional
information concerning the following:
(1) personnel qualification/certification; (2)
technique(s)/calibration standards; (3) extent of examination; (4)
test sensitivity or leakage rate; and (5) report and records
retention requirements.
20.12.2 Equipment (Gages) If dial indicating or recording
pressure gages are used, the dial
should be graduated over a range of about double the intended
orrequired pressure; however, in no case shall the gage be less
than
or more than 4 times the required pressure. These limits do
notapply to dial indicating and recording vacuum gages. Other
gagerange requirements may be specified in the applicable
MandatoryAppendix for the test technique being used. The gage
location forpressure/vacuum leak testing shall be connected to the
componentin a remote location, with the gage position readily
visible to thetest operator throughout the duration of
pressurizing, evacuating,testing, and depressurizing/venting. For
large vessels or systems,a recording-type gage is recommended.
20.12.3 Requirements The surface(s) to be tested shall be clean
and free of any conta-
minants; all openings shall be sealed using plugs, covers, or
othersuitable material that can readily be removed after the test.
Theminimum metal temperature for all components during a test
shallbe as required in the referencing Code section. Components
thatare pressure-leak-tested shall not be tested at a pressure
exceeding25% of the design pressure unless specified otherwise by
the ref-erencing Code section.
20.12.4 Technique Before performing a sensitive leak test
method, it may be expe-
dient to perform a preliminary test to detect and eliminate
grossleaks. It is recommended that leak testing be performed before
therequired hydrostatic or hydropneumatic test.
20.12.5 Calibration All pressure/vacuum dial indicating or
recording gages shall be
calibrated against either a standard deadweight tester, a
calibratedmaster gage, or a mercury column, and recalibration shall
be per-formed at least once a year when in use. All gages shall
providean accuracy within the manufacturers listed accuracy
values.Temperature-measuring devices shall also be calibrated in
accor-dance with the applicable Mandatory Appendix or the
referencingCode section. Permeation-type leak standards shall leak
throughfused glass or quartz. The standard shall have a helium leak
ratein the range of to std m3/sec. Capillary-typeleak standards
shall be a calibrated halogen or helium capillaryleak through a
tube. The standard shall have a leak rate of
to std m3/sec.
20.12.6 Evaluation The acceptance standards used for the test
shall be as required
by the referencing Code section. The supplemental leak
testing
1 * 10-51 * 10-4
1 * 10-101 * 10-6
112
formulas for calculating leak rates for the method or
techniqueused are provided in the applicable Mandatory
Appendices.
20.12.7 Documentation A test report shall contain the following
minimum information:
(1) date of test; (2) name and certification level of operator;
(3) test procedure number and revision; (4) test method or
technique; (5) test results; (6) component identification; (7)
instrument, calibrated leak standard, and material identifi-
cation; (8) test conditions, test pressure, and gas
concentration; (9) gage(s) manufacturer, model, range, and
identification;
(10) temperature-measuring device used and identificationnumber;
and
(11) sketch showing method or technique setup.
20.12.8 Record Retention The test report must be maintained in
accordance with the
requirement of the referencing Code section.
20.13 ACOUSTIC EMISSION EXAMINATION Articles 11, 12, and 13
address acoustic emission examination
methodology. To the best of the authors knowledge, to date
noCode sections have adopted any of these articles. Section VIII
hasapproved in Code Case 1968 the use of Article 12 for
examina-tion of specific low-pressure containers, and Section XI
hasapproved the use of Article 13 for a specific application.
Usersshould refer to the Code Case listing for the respective Code
sec-tions for the necessary details.
20.14 ARTICLE 11: ACOUSTIC EMISSIONEXAMINATION OF
FIBER-REINFORCED PLASTIC VESSELS
Acoustic emission (AE) of fiber-reinforced plastic vessels
fallsunder the jurisdiction of Section X. Several references to
Article11 are found in Section X, including the following
paragraphs:RQ-142 (acceptance test for qualifying Class II vessel
design andfabrication), RT-111 (Article 11 provisions should be
included inNDT Level II qualification), RT-521 (calibration of AE
equip-ment), and several references in RT-620 (acceptance tests
forClass II vessels). The article includes the following
threeMandatory Appendices:
Appendix I, Instrumentation Performance Requirements. Appendix
II, Instrument Calibration. Appendix III, Glossary of Terms.
20.14.1 General When this article is specified by a referencing
Code section, the
methods and techniques shall be used together with Article
1.Discontinuities located by AE must be examined by other
NDEmethods and the test results evaluated in accordance with
theapplicable acceptance criteria.
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20.14.2 Requirements
20.14.2.1 Vessel Conditioning For tanks and vessels that
havebeen previously stressed, the operating pressure or load must
bereduced in accordance with the operating levels provided in
T-1121.
20.14.2.2 Vessel Stressing Arrangements must be made tostress
the vessel at the prescribed design pressure or load, and therate
of application must be sufficient to expedite the examinationwith
minimum extraneous noise.
20.14.2.3 Environmental Conditions Vessel and fluid
temper-atures are critical and are listed for various
conditions.
20.14.2.4 Noise Elimination Extraneous noise must be mini-mized
because it may mask AE signals. Instrument settings shallbe as
prescribed in Mandatory Appendix II.
20.14.2.5 Sensors The mounting of sensors is critical, and
thearticle describes requirements for mounting sensors and
frequencychannels required for both high and low frequencies.
20.14.2.6 Written Procedure The AE examination shall beperformed
in accordance with a written procedure when requiredby the
referencing Code section. The procedure shall include as aminimum
the following information:
(1) materials and configurations to be examined,
includingdimensions and product form;
(2) method for determining sensor locations; (3) sensor
locations; (4) couplant; (5) sensor type, frequency, and location;
(6) equipment type and frequency; (7) description of system
calibration; (8) data to be recorded and method of recording; (9)
report requirements;
(10) postexamination cleaning used; and (11) qualification of
the examiners.
20.14.3 Additional Requirements The Article provides further
extensive requirement details
addressing the following:
(1) equipment and supplies; (2) application requirements; (3)
calibration; (4) evaluation; and (5) documentation. Users should
thoroughly review these specific details when
preparing their test procedure. Nonmandatory Appendix A(Sensor
Placement Guidelines) should also be reviewed.
20.15 ARTICLE 12: ACOUSTIC EMISSIONEXAMINATION OF
METALLICVESSELS DURING PRESSURETESTING
This article describes the methodology for conductingthe AE
examination of metallic vessels during acceptancepressure testing
when specified by a referencing Code section.
There are three Mandatory Appendices accompanying
thearticle:
Appendix I, Instrumentation Performance Requirements. Appendix
II, Instrumentation Calibration and Cross-
Referencing. Appendix III, Glossary of Terms.
The referencing Code section should be consulted for the
fol-lowing specific requirements:
(1) personnel qualification/certification; (2) extent of
examination or volume(s) to be examined; (3) acceptance criteria;
(4) report requirements; and (5) content of records and records
retention. When this article is specified by a referencing Code
section, it
is used together with Article 1.
20.15.1 General The objectives of the AE examination are to
locate and monitor
emission sources caused by surface and internal
discontinuities.All relevant indications caused by AE sources must
be examinedand evaluated by other NDE methods.
20.15.2 Requirements
20.15.2.1 Vessel Stressing The referencing Code section
shouldprovide the necessary detailed information to stress the
vesselusing internal pressure.
20.15.2.2 Noise Reduction External noise sources should
beminimized, and the noise level must be below the system
examina-tion threshold.
20.15.2.3 Sensor Frequency Recommended sensor frequencyis
provided in Nonmandatory Appendix B. Sensor mounting, con-tact, and
location details are provided in the general section.
20.15.2.4 Written Procedure The examination shall be performed
in accordance with a written procedure and, as a minimum,the
procedure shall include the following:
(1) material and configurations to be examined; (2) background
noise measurements; (3) sensor type, frequency, and manufacturer;
(4) method of sensor attachment; (5) type of couplant; (6)
instrument type and filter frequency; (7) sensor locations; (8)
method used for sensor selection; (9) a description of system
calibration(s);
(10) data to be recorded and method of recording; (11)
postexamination cleaning used; (12) report requirements; and (13)
qualification/certification of examiner(s).
20.15.3 Other Requirements The article provides additional
specific requirement details on
application requirements, calibration, evaluation, and
documenta-tion. Consequently, the article should be carefully
reviewed whenthe user prepares the written procedure. Nonmandatory
Appendix
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A (Sensor Placement Guidelines) and Nonmandatory Appendix
B(Supplemental Information for conducting AE Examinations)should
also be reviewed when