ASME BPVC.V-2021
SECTION V
2021
ASME Boiler and
Pressure Vessel Code
An International Code
N on de st ruct iv e
Exa min a t ion
ASME BPVC.V-2021
ARTICLE 1
SUBSECTION A
NONDESTRUCTIVE METHODS OF
EXAMINATION
ARTICLE 1
GENERAL REQUIREMENTS
T-110
SCOPE
T-120
(a) This Section of the Code contains requirements and
methods for nondestructive examination (NDE), which
are Code requirements to the extent they are specifically
referenced and required by other Code Sections or referencing documents. These NDE methods are intended to
detect surface and internal imperfections in materials,
welds, fabricated parts, and components. They include
radiographic examination, ultrasonic examination, liquid
penetrant examination, magnetic particle examination,
eddy current examination, visual examination, leak testing, and acoustic emission examination. See Nonmandatory Appendix A of this Article for a listing of common
imperfections and damage mechanisms, and the NDE
methods that are generally capable of detecting them.
(b) For general terms such as inspection, flaw, discontinuity, evaluation, etc., refer to Mandatory Appendix I.
(c) New editions of Section V may be used beginning
with the date of issuance and become mandatory 6
months after the date of issuance unless modified by
the referencing document.
(d) Code Cases are permissible and may be used, beginning with the date of approval by ASME. Only Code Cases
that are specifically identified as being applicable to this
Section may be used. At the time a Code Case is applied,
only the latest revision may be used. Code Cases that have
been incorporated into this Section or have been annulled
shall not be used, unless permitted by the referencing
Code. Qualifications using the provisions of a Code Case
remain valid after the Code Case is annulled. The Code
Case number shall be listed on the NDE Procedure or Personnel Certification, as applicable.
GENERAL
(a) Subsection A describes the methods of nondestructive examination to be used if referenced by other Code
Sections or referencing documents.
(b) Subsection B lists Standards covering nondestructive examination methods which have been accepted as
standards. These standards are not mandatory unless
specifically referenced in whole or in part in Subsection
A or as indicated in other Code Sections or referencing
documents. Where there is a conflict between Subsection
A and Subsection B, the requirements of Subsection A
take precedence.
(c) Any reference to a paragraph of any Article in Subsection A of this Section includes all of the applicable rules
in the paragraph. In every case, reference to a paragraph
includes all the subparagraphs and subdivisions under
that paragraph.
NOTE: For example, a reference to T-270 includes all of the rules
contained in T-271 through T-277.3.
(d) Reference to a standard contained in Subsection B
is mandatory only to the extent specified.
NOTE: For example, T-233 requires that Image Quality Indicators be
manufactured and identified in accordance with the requirements or
alternatives allowed in SE-747 or SE-1025, and Appendices, as appropriate for the style of IQI to be used. These are the only parts
of either SE-747 or SE-1025 that are mandatory in Article 2. In many
cases, Subsection B documents are not mandatory and are intended
only for guidance or reference use.
(e) For those documents that directly reference this
Article for the qualification of NDE personnel, the qualification shall be in accordance with their employer’s written practice which shall be in accordance with one of the
following documents:
(1) SNT-TC-1A (2016 Edition),1 Personnel Qualification and Certification in Nondestructive Testing, as
amended by Mandatory Appendix III; or
1
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ARTICLE 1
ASME BPVC.V-2021
(2) ANSI/ASNT CP-189 (2020 Edition),1 ASNT Standard for Qualification and Certification of Nondestructive
Testing Personnel, as amended by Mandatory Appendix
IV
(f) National or international central certification
programs, such as ISO 9712–based programs, may alternatively be used to fulfill the written practice requirements of (e) for training, experience, general
examination, basic examination, and method examination, as applicable.
(g) In addition to the requirements described in (e) or
(f) above, if the techniques of computed radiography (CR),
digital radiography (DR), phased-array ultrasonic
(PAUT), ultrasonic time-of-flight diffraction (TOFD), or ultrasonic full matrix capture (FMC) are to be used, the
training, experience, and examination requirements
found in Article 1, Mandatory Appendix II shall also be included in the employer’s written practice for each technique as applicable.
(h) Alternatively, performance-based qualification programs, in accordance with ASME ANDE-1-2015, ASME
Nondestructive Examination and Quality Control Central
Qualification and Certification Program, may be used for
training, experience, examination, and certification activities as specified in the written practice.
(i) When the referencing Code Section does not specify
qualifications or does not reference directly Article 1 of
this Section, qualification may simply involve a demonstration to show that the personnel performing the nondestructive examinations are competent to do so in
ac cordance with the organizatio n’s established
procedures.
(j) The user of this Article is responsible for the qualification and certification of NDE Personnel in accordance
with the requirements of this Article. The organization’s2
Quality Program shall stipulate how this is to be accomplished. Qualifications in accordance with a prior edition
of SNT-TC-1A, or CP-189 are valid until recertification. Recertification or new certification shall be in accordance
with the edition of SNT-TC-1A or CP-189 specified in (e)
above. When any of the techniques included in (g) above
are used, the additional requirements of that paragraph
shall also apply.
(k) Limited certification of nondestructive examination
personnel who do not perform all of the operations of a
nondestructive method that consists of more than one operation, or who perform nondestructive examinations of
limited scope, may be based on fewer hours of training
and experience than recommended in SNT-TC-1A or
CP-189. Any limitations or restrictions placed upon a person’s certification shall be described in the written practice and on the certification.
(l) Either U.S. Customary Units or SI Units may be used
for compliance with all requirements of this edition, but
one system shall be used consistently throughout for all
phases of construction.
(1) Either the U.S. Customary Units or SI Units that
are listed in Section V Mandatory Appendix II (in the rear
of Section V and listed in other Code books) are identified
in the text, or are identified in the nomenclature for equations shall be used consistently for all phases of construction (e.g., materials, design, fabrication, and reports).
Since values in the two systems are not exact equivalents,
each system shall be used independently of the other
without mixing U.S. Customary Units and SI Units.
(2) When SI Units are selected, U.S. Customary values
in referenced specifications that do not contain SI Units
shall be converted to SI values to at least three significant
figures for use in calculations and other aspects of
construction.
T-130
EQUIPMENT
It is the responsibility of the Code User to ensure that
the examination equipment being used conforms to the
requirements of this Code Section.
T-150
PROCEDURE
(a) When required by the referencing Code Section, all
nondestructive examinations performed under this Code
Section shall be performed following a written procedure.
A procedure demonstration shall be performed to the satisfaction of the Inspector. When required by the referencing Code Section, a personnel demonstration may be
used to verify the ability of the examiner to apply the examination procedure. The examination procedure shall
comply with the applicable requirements of this Section
for the particular examination method. Written procedures shall be made available to the Inspector on request.
At least one copy of each procedure shall be readily available to the Nondestructive Examination Personnel for
their reference and use.
(b) The nondestructive examination methods and techniques included in this Section are applicable to most geometric configurations and materials encountered in
fabrication under normal conditions. Whenever special
configurations or materials require modified methods
and techniques, the organization shall develop special
procedures which are equivalent or superior to the methods and techniques described in this Code Section, and
which are capable of producing interpretable examination results under the special conditions. Such special
procedures may be modifications or combinations of
methods described or referenced in this Code Section. A
procedure demonstration shall be performed to verify
the technique is capable of detecting discontinuities under the special conditions equal to the capabilities of
the method when used under more general conditions.
These special procedures shall be submitted to the
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ASME BPVC.V-2021
Inspector for acceptance when required by the referencing Code Section, and shall be adopted as part of the
Manufacturer’s quality control program.
(c) When a referencing Code Section requires an examination to be performed in accordance with the requirements of this Section, it shall be the responsibility of the
organization to establish nondestructive examination
procedures and personnel qualification and certification
procedures conforming to the referenced requirements.
(d) When qualification of the written examination procedure is required by the referencing Code Section, a qualification demonstration shall be performed prior to
acceptance of production examinations. The qualification
demonstration shall be performed
(1) under the control and supervision of a Level III
Examiner who is qualified and certified for performing
the examination method and technique specified by the
procedure, and shall be witnessed by the Inspector. The
supervising Level III may be an employee of the qualifying
organization or a subcontractor organization.
(2) on a minimum of one test specimen having flaws
whose size, location, orientation, quantity, and characterization have been determined prior to the demonstration
and are known only by the supervising Level III Examiner.
(-a) The maximum acceptable flaw size, required
flaw orientation, and minimum number of flaws shall be
as specified by the referencing Code Section.
(-b) Natural flaws are preferred over artificial
flaws whenever possible.
(3) by a Level II or Level III Examiner (other than the
supervising Level III) who is qualified and certified to perform the examination method and technique specified by
the written procedure.
The procedure shall be considered qualified when
the supervising Level III and the Inspector are satisfied
that indications produced by the demonstrated procedure
effectively reveal the size, location, orientation, quantity,
and characterization of the flaws known to be present
in the examined test specimen.
The qualification demonstration shall be documented as required by the referencing Code Section and by
this Section, as set forth in the applicable Article for the
examination method and the applicable Appendix for
the specified examination technique. The qualification
document shall be annotated to indicate qualification of
the written procedure, and identify the examined test
specimen. The name and/or identity and signature of
the supervising Level III and the witnessing Inspector
shall be added to indicate their acceptance of the procedure qualification.
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T-160
ARTICLE 1
(b) When special procedures are developed [see
T-150(b)], the Code User shall specify what calibration
is necessary, when calibration is required.
T-170
EXAMINATIONS AND INSPECTIONS
(a) The Inspector concerned with the fabrication of the
vessel or pressure part shall have the duty of verifying to
the Inspector's satisfaction that all examinations required
by the referencing Code Section have been made to
the requirements of this Section and the referencing
document(s). The Inspector shall have the right to witness any of these examinations to the extent stated in
the referencing document(s). Throughout this Section of
the Code, the word Inspector shall be as defined and qualified as required by the referencing Code Section or referencing document(s).
(b) The special distinction established in the various
Code Sections between inspection and examination and
the personnel performing them is also adopted in this
Code Section. In other words, the term inspection applies
to the functions performed by the Inspector, but the term
examination applies to those quality control functions
performed by personnel employed by the organization.
One area of occasional deviation from these distinctions
exists. In the ASTM Standard Methods and Recommended
Practices incorporated in this Section of the Code by reference or by reproduction in Subsection B, the words inspection or Inspector, which frequently occur in the text or
titles of the referenced ASTM documents, may actually describe what the Code calls examination or examiner. This
situation exists because ASTM has no occasion to be concerned with the distinctions which the Code makes between inspection and examination, since ASTM activities
and documents do not involve the Inspector described
in the Code Sections. However, no attempt has been made
to edit the ASTM documents to conform with Code usage;
this should cause no difficulty if the users of this Section
recognize that the terms inspection, testing, and examination in the ASTM documents referenced in Subsection B
do not describe duties of the Inspector but rather describe
the things to be done by the organization’s examination
personnel.
T-180
EVALUATION
The acceptance criteria for the NDE methods in this
Section shall be as stated in the referencing Code Section,
and where provided in the Articles of this Section. Acceptance criteria in the referencing Code Section shall take
precedence.
CALIBRATION
(a) The organization shall assure that all equipment calibrations required by Subsection A and/or Subsection B
are performed.
3
ARTICLE 1
T-190
ASME BPVC.V-2021
RECORDS/DOCUMENTATION
T-150(a) or T-150(b) are not specified by the referencing
Code Section, the following information shall be recorded
as a minimum:
(1) name of organization responsible for preparation
and approval of the examination procedure
(2) examination method applied
(3) procedure number or designation
(4) number and date of most recent revision
(5) date of the demonstration
(6) name and/or identity and certification level (if
applicable) of personnel performing demonstration
(d) Retention of examination records and related documentation (e.g., radiographs and review forms, ultrasonic
scan files, etc.) shall be as specified by the referencing
Code Section.
(e) Digital images and reviewing software shall be retained under an appropriate record retention system that
is capable of securely storing and retrieving data for the
time period specified by the referencing Code Section.
(a) Documentation and records shall be prepared as
specified by the referencing Code Section and the applicable requirements of this Section. Examination records
shall include the following information as a minimum:
(1) date of the examination
(2) name and/or identity and certification level (if
applicable) for personnel performing the examination
(3) identification of the weld, part, or component examined including weld number, serial number, or other
identifier
(4) examination method, technique, procedure identification, and revision
(5) results of the examination
(b) Personnel qualification and procedure performance
demonstrations performed in compliance with the requirements of T-150(a) or T-150(b) shall be documented
as specified by the referencing Code Section.
(c) When documentation requirements for personnel
qualification and procedure performance demonstrations
performed in compliance with the requirements of
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ASME BPVC.V-2021
ARTICLE 2
ARTICLE 2
RADIOGRAPHIC EXAMINATION
T-210
SCOPE
T-222.2 Welds. The weld ripples or weld surface irregularities on both the inside (where accessible) and
outside shall be removed by any suitable process to such
a degree that the images of surface irregularities cannot
mask or be confused with the image of any discontinuity
on the resulting radiograph.
The finished surface of all butt-welded joints may be
flush with the base material or may have reasonably uniform crowns, with reinforcement not to exceed that specified in the referencing Code Section.
The radiographic method described in this Article for
examination of materials including castings and welds
shall be used together with Article 1, General Requirements. Definitions of terms used in this Article are in
Article 1, Mandatory Appendix I, I-121.1, RT —
Radiography.
Certain product-specific, technique-specific, and
application-specific requirements are also given in other
Mandatory Appendices of this Article, as listed in the table
of contents. These additional requirements shall also be
complied with when an Appendix is applicable to the
r a d i o g r a p h i c o r r a d i o s c opic examination being
conducted.
T-220
GENERAL REQUIREMENTS
T-221
PROCEDURE REQUIREMENTS
T-223
A lead symbol “B,” with minimum dimensions of 7/16 in.
(11 mm) in height and 1/16 in. (1.5 mm) in thickness, shall
be attached to the back of each film holder during each exposure to determine if backscatter radiation is exposing
the film. The lead symbol “B” shall be placed in a location
so that it would appear within an area on the radiograph
that meets the requirements of T-282, VIII-288, or
IX-288, as applicable.
T-221.1 Written Procedure. Radiographic examination shall be performed in accordance with a written procedure. Each procedure shall include at least the following
information, as applicable:
(a) material type and thickness range
(b) isotope or maximum X-ray voltage used
(c) source-to-object distance (D in T-274.1)
(d) distance from source side of object to film (d in
T-274.1)
(e) source size (F in T-274.1)
(f) film brand and designation
(g) screens used
T-224
SYSTEM OF IDENTIFICATION
A system shall be used to produce on each radiograph
an identification that is traceable to the item being radiographed and that is permanent for the required retention
period of the radiograph. This information shall include
the contract, component, weld number, or part number,
as appropriate. In addition, the Manufacturer’s symbol
or name and the date of the radiograph shall be included
with the identification information on each radiograph.
An NDE subcontractor’s name or symbol may also be used
together with that of the Manufacturer. This identification
system does not necessarily require that the information
appear as radiographic images. In any case, this information shall not obscure the area of interest.
T-221.2 Procedure Demonstration. Demonstration
of the density and image quality indicator (IQI) image requirements of the written procedure on production or
technique radiographs shall be considered satisfactory
evidence of compliance with that procedure.
T-225
T-222
BACKSCATTER RADIATION
SURFACE PREPARATION
MONITORING DENSITY LIMITATIONS OF
RADIOGRAPHS
Either a densitometer or step wedge comparison film
shall be used for judging film density.
T-222.1 Materials Including Castings. Surfaces shall
satisfy the requirements of the applicable materials specification or referencing Code Section, with additional conditioning, if necessary, by any suitable process to such a
degree that the images of surface irregularities cannot
mask or be confused with the image of any discontinuity
on the resulting radiograph.
T-226
EXTENT OF EXAMINATION
The extent of radiographic examination shall be as specified by the referencing Code Section.
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ARTICLE 2
T-230
T-231
ASME BPVC.V-2021
EQUIPMENT AND MATERIALS
Table T-233.2
Wire IQI Designation, Wire Diameter, and
Wire Identity
FILM
T-231.1 Selection. Radiographs shall be made using
industrial radiographic film.
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Set A
Wire Diameter,
in. (mm)
T-231.2 Processing. Standard Guide for Controlling
the Quality of Industrial Radiographic Film Processing,
SE-999, or Sections 23 through 26 of Standard Guide for
Radiographic Examination Using Industrial Radiographic
Film, SE-94/SE-94M, may be used as a guide for processing film, except that Section 8.1 of SE-999 is not required.
T-232
0.0032
0.004
0.005
0.0063
0.008
0.010
INTENSIFYING SCREENS
Wire
Identity
Wire Diameter,
in. (mm)
Wire
Identity
1
2
3
4
5
6
0.010 (0.25)
0.013 (0.33)
0.016 (0.41)
0.020 (0.51)
0.025 (0.64)
0.032 (0.81)
6
7
8
9
10
11
Wire
Identity
Wire Diameter,
in. (mm)
Wire
Identity
0.100 (2.54)
0.126 (3.20)
0.160 (4.06)
0.200 (5.08)
0.250 (6.35)
0.320 (8.13)
16
17
18
19
20
21
(0.08)
(0.10)
(0.13)
(0.16)
(0.20)
(0.25)
Set C
Intensifying screens may be used when performing
radiographic examination in accordance with this Article.
T-233
Set B
Wire Diameter,
in. (mm)
0.032 (0.81)
0.040 (1.02)
0.050 (1.27)
0.063 (1.60)
0.080 (2.03)
0.100 (2.54)
IMAGE QUALITY INDICATOR (IQI) DESIGN
T-233.1 Standard IQI Design. IQIs shall be either the
hole type or the wire type. Hole-type IQIs shall be manufactured and identified in accordance with the requirements or alternates allowed in SE-1025. Wire-type IQIs
shall be manufactured and identified in accordance with
the requirements or alternates allowed in SE-747, except
that the largest wire number or the identity number may
be omitted. ASME standard IQIs shall consist of those in
Table T-233.1 for hole type and those in Table T-233.2
for wire type.
Set D
11
12
13
14
15
16
Table T-233.1
Hole-Type IQI Designation, Thickness, and Hole Diameters
IQI Designation
5
7
10
12
15
17
20
25
30
35
40
45
50
60
70
80
100
120
140
160
200
240
280
IQI Thickness,
in. (mm)
0.005
0.0075
0.010
0.0125
0.015
0.0175
0.020
0.025
0.030
0.035
0.040
0.045
0.050
0.060
0.070
0.080
0.100
0.120
0.140
0.160
0.200
0.240
0.280
(0.13)
(0.19)
(0.25)
(0.32)
(0.38)
(0.44)
(0.51)
(0.64)
(0.76)
(0.89)
(1.02)
(1.14)
(1.27)
(1.52)
(1.78)
(2.03)
(2.54)
(3.05)
(3.56)
(4.06)
(5.08)
(6.10)
(7.11)
1T Hole Diameter,
in. (mm)
0.010
0.010
0.010
0.0125
0.015
0.0175
0.020
0.025
0.030
0.035
0.040
0.045
0.050
0.060
0.070
0.080
0.100
0.120
0.140
0.160
0.200
0.240
0.280
42
(0.25)
(0.25)
(0.25)
(0.32)
(0.38)
(0.44)
(0.51)
(0.64)
(0.76)
(0.89)
(1.02)
(1.14)
(1.27)
(1.52)
(1.78)
(2.03)
(2.54)
(3.05)
(3.56)
(4.06)
(5.08)
(6.10)
(7.11)
2T Hole Diameter,
in. (mm)
0.020
0.020
0.020
0.025
0.030
0.035
0.040
0.050
0.060
0.070
0.080
0.090
0.100
0.120
0.140
0.160
0.200
0.240
0.280
0.320
0.400
0.480
0.560
(0.51)
(0.51)
(0.51)
(0.64)
(0.76)
(0.89)
(1.02)
(1.27)
(1.52)
(1.78)
(2.03)
(2.29)
(2.54)
(3.05)
(3.56)
(4.06)
(5.08)
(6.10)
(7.11)
(8.13)
(10.16)
(12.19)
(14.22)
4T Hole
Diameter,
in. (mm)
0.040 (1.02)
0.040 (1.02)
0.040 (1.02)
0.050 (1.27)
0.060 (1.52)
0.070 (1.78)
0.080 (2.03)
0.100 (2.54)
0.120 (3.05)
0.140 (3.56)
0.160 (4.06)
0.180 (4.57)
0.200 (5.08)
0.240 (6.10)
0.280 (7.11)
0.320 (8.13)
0.400 (10.16)
0.480 (12.19)
0.560 (14.22)
0.640 (16.26)
…
…
…
ASME BPVC.V-2021
T-233.2 Alternative IQI Design. IQIs designed and
manufactured in accordance with other national or international standards may be used provided the requirements of either (a) or (b) below, and the material
requirements of T-276.1 are met.
(a) Hole-Type IQIs. The calculated Equivalent IQI Sensitivity (EPS), per SE-1025, Appendix X1, is equal to or better than the required standard hole-type IQI.
(b) Wire-Type IQIs. The alternative wire IQI essential
wire diameter is equal to or less than the required standard IQI essential wire.
T-234
by comparison with a national standard step tablet unless, prior to first use, it was maintained in the original
light-tight and waterproof sealed package as supplied
by the manufacturer. Step wedge calibration films may
be used without verification for one year upon opening,
provided it is within the manufacturer’s stated shelf life.
(b) The densitometer manufacturer’s step-by-step instructions for the operation of the densitometer shall be
followed.
(c) The density steps closest to 1.0, 2.0, 3.0, and 4.0 on
the national standard step tablet or step wedge calibration film shall be read.
(d) The densitometer is acceptable if the density readings do not vary by more than ±0.05 density units from
the actual density stated on the national standard step tablet or step wedge calibration film.
FACILITIES FOR VIEWING OF
RADIOGRAPHS
Viewing facilities shall provide subdued background
lighting of an intensity that will not cause reflections, shadows, or glare on the radiograph that interfere with the
interpretation process. Equipment used to view radiographs for interpretation shall provide a variable light
source sufficient for the essential IQI hole or designated
wire to be visible for the specified density range. The
viewing conditions shall be such that light from around
the outer edge of the radiograph or coming through lowdensity portions of the radiograph does not interfere with
interpretation.
T-260
T-261
T-262.2 Step Wedge Comparison Films. Step wedge
comparison films shall be verified prior to first use, unless
performed by the manufacturer, as follows:
(a) The density of the steps on a step wedge comparison film shall be verified by a calibrated densitometer.
(b) The step wedge comparison film is acceptable if the
density readings do not vary by more than ±0.1 density
units from the density stated on the step wedge comparison film.
T-262.3 Periodic Verification.
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(a) Densitometers. Periodic calibration verification
checks shall be performed as described in T-262.1 at
the beginning of each shift, after 8 hr of continuous use,
or after change of apertures, whichever comes first.
(b) Step Wedge Comparison Films. Verification checks
shall be performed annually per T-262.2.
CALIBRATION
SOURCE SIZE
T-261.1 Verification of Source Size. The equipment
manufacturer’s or supplier’s publications, such as technical manuals, decay curves, or written statements documenting the actual or maximum source size or focal
spot, shall be acceptable as source size verification.
T-262.4 Documentation.
(a) Densitometers. Densitometer calibrations required
by T-262.1 shall be documented, but the actual readings
for each step do not have to be recorded. Periodic densitometer verification checks required by T-262.3(a) do not
have to be documented.
(b) Step Wedge Calibration Films. Step wedge calibration film verifications required by T-262.1(a) shall be
documented, but the actual readings for each step do
not have to be recorded.
(c) Step Wedge Comparison Films. Step wedge comparison film verifications required by T-262.2 and
T-262.3(b) shall be documented, but the actual readings
for each step do not have to be recorded.
T-261.2 Determination of Source Size. When manufacturer’s or supplier’s publications are not available,
source size may be determined as follows:
(a) X-Ray Machines. For X-ray machines operating at
1,000 kV and less, the focal spot size may be determined
in accordance with SE-1165, Standard Test Method for
Measurement of Focal Spots of Industrial X-Ray Tubes
by Pinhole Imaging.
(b) Iridium-192 Sources. For Iridium-192, the source
size may be determined in accordance with SE-1114,
Standard Test Method for Determining the Focal Size of
Iridium-192 Industrial Radiographic Sources.
T-262
ARTICLE 2
DENSITOMETER AND STEP WEDGE
COMPARISON FILM
T-262.1 Densitometers. Densitometers shall be calibrated at least every 3 months during use as follows:
(a) A national standard step tablet or a step wedge calibration film, traceable to a national standard step tablet
and having at least five steps with neutral densities from
at least 1.0 through 4.0, shall be used. The step wedge calibration film shall have been verified within the last year
T-270
T-271
EXAMINATION
RADIOGRAPHIC TECHNIQUE3
A single-wall exposure technique shall be used for
radiography whenever practical. When it is not practical
to use a single-wall technique, a double-wall technique
43
ARTICLE 2
ASME BPVC.V-2021
T-274
shall be used. An adequate number of exposures shall be
made to demonstrate that the required coverage has been
obtained.
T-274.1 Geometric Unsharpness Determination. ð21Þ
Geometric unsharpness of the radiograph shall be determined in accordance with:
T-271.1 Single-Wall Technique. In the single-wall
technique, the radiation passes through only one wall of
the weld (material), which is viewed for acceptance on
the radiograph.
where
T-271.2 Double-Wall Technique. When it is not practical to use a single-wall technique, one of the following
double-wall techniques shall be used.
D = distance from source of radiation to weld or object
being radiographed
d = distance from source side of weld or object being
radiographed to the film
F = source size: the maximum projected dimension of
the radiating source (or effective focal spot) in
the plane perpendicular to the distance D from
the weld or object being radiographed
U g = geometric unsharpness
(a) Single-Wall Viewing. For materials and for welds in
components, a technique may be used in which the radiation passes through two walls and only the weld (material) on the film-side wall is viewed for acceptance on the
radiograph. When complete coverage is required for circumferential welds (materials), a minimum of three exposures taken 120 deg to each other shall be made.
D and d shall be determined at the approximate center
of the area of interest.
(b) Double-Wall Viewing. For materials and for welds in
components 31/2 in. (89 mm) or less in nominal outside
diameter, a technique may be used in which the radiation
passes through two walls and the weld (material) in both
walls is viewed for acceptance on the same radiograph.
For double-wall viewing, only a source-side IQI shall be
used.
NOTE: Alternatively, a nomograph as shown in Standard Guide for
Radiographic Examination Using Industrial Radiographic Film,
SE-94/SE-94M, may be used.
T-274.2 Geometric Unsharpness Limitations. Recommended maximum values for geometric unsharpness
are as follows:
(1) For welds, the radiation beam may be offset from
the plane of the weld at an angle sufficient to separate the
images of the source-side and film-side portions of the
weld so that there is no overlap of the areas to be interpreted. When complete coverage is required, a minimum
of two exposures taken 90 deg to each other shall be
made for each joint.
Material Thickness, in. (mm)
Under 2 (50)
2 through 3 (50–75)
Over 3 through 4 (75–100)
Greater than 4 (100)
(2) As an alternative, the weld may be radiographed
with the radiation beam positioned so that the images of
both walls are superimposed. When complete coverage is
required, a minimum of three exposures taken at either
60 deg or 120 deg to each other shall be made for each
joint.
T-275
0.020
0.030
0.040
0.070
(0.51)
(0.76)
(1.02)
(1.78)
LOCATION MARKERS
Location markers (see Figure T-275), which shall appear as radiographic images on the radiograph, shall be
placed on the part, not on the exposure holder/cassette.
Their locations shall be permanently marked on the surface of the part being radiographed when permitted, or
on a map, in a manner permitting the area on a radiograph to be accurately traceable to its location on the part,
for the required retention period of the radiograph. In addition, their locations do not limit the area of interest or
the area to be interpreted. Evidence shall also be provided
on the radiograph that the required coverage of the region being examined has been obtained. Location markers
shall be placed as follows.
RADIATION ENERGY
The radiation energy employed for any radiographic
technique shall achieve the density and IQI image requirements of this Article.
T-273
Ug Maximum, in. (mm)
NOTE: Material thickness is the thickness on which the IQI is based.
(3) Additional exposures shall be made if the required radiographic coverage cannot be obtained using
the minimum number of exposures indicated in (1) or
(2) above.
T-272
GEOMETRIC UNSHARPNESS
T-275.1 Single-Wall Viewing.
(a) Source-Side Markers. Location markers shall be
placed on the source side when radiographing the
following:
(1) flat components or longitudinal joints in cylindrical or conical components;
DIRECTION OF RADIATION
The direction of the central beam of radiation should be
centered on the area of interest whenever practical.
44
ð21Þ
Figure T-275
Location Marker Sketches
Source side
acceptable
Film side
unacceptable
Source side
acceptable
Film side
unacceptable
Source side
acceptable
Film side
unacceptable
Curved components with radiation source to
film distance less than radius of component
[See T-275.1(a)(2)]
(b)
Curved components with convex surface
towards radiation source
[See T-275.1(a)(3)]
(c)
45
Either side
location marker
is acceptable
D
ASME BPVC.V-2021
Flat component or longitudinal seam
[See T-275.1(a)(1)]
[See sketch (e) for alternate]
(a)
t
Source side
unacceptable
x
Film side
acceptable
Curved components with radiation source to
film distance greater than radius of curvature
[See T-275.1(b)(1)]
(d)
Radiation source —
Location marker —
Component center —
x
Source side marker alternate
Flat component or logitudinal seam
x = (t / D) (Mf / 2)
x = additional required coverage
beyond film side location marker
t = component thickness
Mf = film side location marker interval
D = source to component distance
[See T-275.1(b)(2)]
(e)
Curved components with radiation source
at center curvature
[See T-275.1(c)]
(f)
ARTICLE 2
LEGEND:
Mf
ARTICLE 2
ASME BPVC.V-2021
referencing Code Section. Physical measurement of the
actual weld reinforcements is not required. Backing rings
or strips shall not be considered as part of the thickness in
IQI selection.
(2) curved or spherical components whose concave
side is toward the source and when the “source-tomaterial” distance is less than the inside radius of the
component;
(3) curved or spherical components whose convex
side is toward the source.
(b) Film-Side Markers
(1) Location markers shall be placed on the film side
when radiographing either curved or spherical components whose concave side is toward the source and when
the “source-to-material” distance is greater than the inside radius.
(2) As an alternative to source-side placement in
T-275.1(a)(1), location markers may be placed on the film
side when the radiograph shows coverage beyond the location markers to the extent demonstrated by Figure
T-275, sketch (e), and when this alternate is documented
in accordance with T-291.
(c) Either Side Markers. Location markers may be
placed on either the source side or film side when radiographing either curved or spherical components whose
concave side is toward the source and the “source-tomaterial” distance equals the inside radius of the
component.
(b) Welds Without Reinforcements. The thickness on
which the IQI is based is the nominal single-wall material
thickness. Backing rings or strips shall not be considered
as part of the thickness in IQI selection.
(c) Actual Values. With regard to (a) and (b) above,
when the actual material/weld thickness is measured,
IQI selection may be based on these known values.
T-276.3 Welds Joining Dissimilar Materials or
Welds With Dissimilar Filler Metal. When the weld metal
is of an alloy group or grade that has a radiation attenuation that differs from the base material, the IQI material
selection shall be based on the weld metal and be in accordance with T-276.1. When the density limits of
T-282.2 cannot be met with one IQI, and the exceptional
density area(s) is at the interface of the weld metal and
the base metal, the material selection for the additional
IQIs shall be based on the base material and be in accordance with T-276.1.
T-275.2 Double-Wall Viewing. For double-wall
viewing, at least one location marker shall be placed adjacent to the weld (or on the material in the area of interest)
for each radiograph.
T-277
T-277.1
T-275.3 Mapping the Placement of Location Markers. When inaccessibility or other limitations prevent
the placement of markers as stipulated in T-275.1 and
T-275.2, a dimensioned map of the actual marker placement shall accompany the radiographs to show that full
coverage has been obtained.
T-276
Placement of IQIs.
(a) Source-Side IQI(s). The IQI(s) shall be placed on the
source side of the part being examined, except for the
condition described in (b).
When, due to part or weld configuration or size, it is not
practical to place the IQI(s) on the part or weld, the IQI(s)
may be placed on a separate block. Separate blocks shall
be made of the same or radiographically similar materials
(as defined in SE-1025 for hole type or SE-747 for wire
type) and may be used to facilitate IQI positioning. There
is no restriction on the separate block thickness, provided
the IQI/area-of-interest density tolerance requirements
of T-282.2 are met.
IQI SELECTION
T-276.1 Material. IQIs shall be selected from either
the same alloy material group or grade as identified in
SE-1025 for hole type or SE-747 for wire type, or from
an alloy material group or grade with less radiation absorption than the material being radiographed.
ð21Þ
USE OF IQIS TO MONITOR RADIOGRAPHIC
EXAMINATION
(1) The IQI on the source side of the separate block
shall be placed no closer to the film than the source side
of the part being radiographed.
T-276.2 Size. The designated hole IQI or essential
wire shall be as specified in Table T-276. A thinner or
thicker hole-type IQI may be substituted for any section
thickness listed in Table T-276, provided an equivalent
IQI sensitivity is maintained. See T-283.2. For wire-type
IQIs, a smaller-diameter wire may be substituted for the
essential wire required for any section thickness listed
in Table T-276.
(a) Welds With Reinforcements. The thickness on which
the IQI is based is the nominal single-wall material thickness plus the weld reinforcement thickness estimated to
be present on both sides of the weld (I.D. and O.D.). The
values used for the estimated weld reinforcement thicknesses shall be representative of the weld conditions
and shall not exceed the maximums permitted by the
(2) The separate block shall be placed as close as possible to the part being radiographed.
(3) When hole-type IQIs are used, the block dimensions shall exceed the IQI dimensions such that the outline of at least three sides of the IQI image shall be
visible on the radiograph.
(b) Film-Side IQI(s). Where inaccessibility prevents
hand placing the IQI(s) on the source side, the IQI(s) shall
be placed on the film side in contact with the part being
examined. A lead letter “F” shall be placed adjacent to
or on the IQI(s), but shall not mask the essential hole
where hole IQIs are used.
46
ð21Þ
ASME BPVC.V-2021
ARTICLE 2
ð21Þ
Table T-276
IQI Selection
IQI
Source Side
Nominal Single-Wall Material Thickness
Range, in. (mm)
≤0.25 (≤6.4)
>0.25 through 0.375 (>6.4 through 9.5)
>0.375 through 0.50 (>9.5 through 12.7)
>0.50 through 0.75 (>12.7 through 19.0)
>0.75 through 1.00 (>19.0 through 25.4)
>1.00 through 1.50 (>25.4 through 38.1)
>1.50 through 2.00 (>38.1 through 50.8)
>2.00 through 2.50 (>50.8 through 63.5)
>2.50 through 4.00 (>63.5 through 101.6)
>4.00 through 6.00 (>101.6 through 152.4)
>6.00 through 8.00 (>152.4 through 203.2)
>8.00 through 10.00 (>203.2 through 254.0)
>10.00 through 12.00 (>254.0 through 304.8)
>12.00 through 16.00 (>304.8 through 406.4)
>16.00 through 20.00 (>406.4 through 508.0)
Film Side
Hole-Type
Designation
Essential
Hole
Wire-Type
Essential Wire
Hole-Type
Designation
Essential
Hole
Wire-Type
Essential Wire
12
15
17
20
25
30
35
40
50
60
80
100
120
160
200
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
5
6
7
8
9
10
11
12
13
14
16
17
18
20
21
10
12
15
17
20
25
30
35
40
50
60
80
100
120
160
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
2T
4
5
6
7
8
9
10
11
12
13
14
16
17
18
20
(c) IQI Placement for Welds — Hole IQIs. The IQI(s) may
be placed adjacent to or on the weld. The identification
number(s) and, when used, the lead letter “F,” shall not
be in the area of interest, except when geometric configuration makes it impractical.
(d) IQI Placement for Welds — Wire IQIs. The IQI(s)
shall be placed on the weld so that the lengths of the wires
are transverse to the longitudinal axis of the weld. The IQI
identification and, when used, the lead letter “F,” shall not
be in the area of interest, except when geometric configuration makes it impractical.
(e) IQI Placement for Materials Other Than Welds. The
IQI(s) with the IQI identification and, when used, the lead
letter “F,” may be placed in the area of interest.
(-b) When a section or sections of the circumference, where the length between the ends of the outermost
sections span 240 or more deg, is radiographed using one
or more film holders. Additional film locations may be required to obtain necessary IQI spacing.
(2) For cylindrical components where the source is
placed on the axis of the component for a single exposure,
at least three IQIs, with one placed at each end of the span
of the circumference radiographed and one in the approximate center of the span, are required under the following
conditions:
(-a) When a section of the circumference, the
length of which is greater than 120 deg and less than
240 deg, is radiographed using just one film holder, or;
(-b) When a section or sections of the circumference, where the length between the ends of the outermost
sections span less than 240 deg, is radiographed using
more than one film holder.
(3) In (1) and (2) above, where sections of longitudinal welds adjoining the circumferential weld are radiographed simultaneously with the circumferential weld,
an additional IQI shall be placed on each longitudinal
weld at the end of the section most remote from the junction with the circumferential weld being radiographed.
(4) For spherical components where the source is
placed at the center of the component for a single exposure, at least three IQIs, spaced approximately 120 deg
apart, are required under the following conditions:
(-a) When a complete circumference is radiographed using one or more film holders, or;
T-277.2 Number of IQIs. When one or more film
holders are used for an exposure, at least one IQI image
shall appear on each radiograph except as outlined in
(b) below.
(a) Multiple IQIs. If the requirements of T-282 are met
by using more than one IQI, one shall be representative
of the lightest area of interest and the other the darkest
area of interest; the intervening densities on the radiograph shall be considered as having acceptable density.
(b) Special Cases4
(1) For cylindrical components where the source is
placed on the axis of the component for a single exposure,
at least three IQIs, spaced approximately 120 deg apart,
are required under the following conditions:
(-a) When the complete circumference is radiographed using one or more film holders, or;
47
ARTICLE 2
ASME BPVC.V-2021
(-b) When a section or sections of a circumference,
where the length between the ends of the outermost sections span 240 or more deg, is radiographed using one or
more film holders. Additional film locations may be required to obtain necessary IQI spacing.
(5) For spherical components where the source is
placed at the center of the component for a single exposure, at least three IQIs, with one placed at each end of
the span of the circumference radiographed and one in
the approximate center of the span, are required under
the following conditions:
(-a) When a section of a circumference, the length
of which is greater than 120 deg and less than 240 deg, is
radiographed using just one film holder, or;
(-b) When a section or sections of a circumference,
where the length between the ends of the outermost sections span less than 240 deg is radiographed using more
than one film holder.
(6) In (4) and (5) above, where other welds are
radiographed simultaneously with the circumferential
weld, one additional IQI shall be placed on each other
weld.
(7) For segments of a flat or curved (i.e., ellipsoidal,
torispherical, toriconical, elliptical, etc.) component
where the source is placed perpendicular to the center
of a length of weld for a single exposure when using more
than three film holders, at least three IQIs, one placed at
each end of the radiographed span and one in the approximate center of the span, are required.
(8) When an array of components in a circle is radiographed, at least one IQI shall show on each component
image.
(9) In order to maintain the continuity of records involving subsequent exposures, all radiographs exhibiting
IQIs that qualify the techniques permitted in accordance
with (1) through (7) above shall be retained.
(b) processing defects such as streaks, watermarks, or
chemical stains;
(c) scratches, finger marks, crimps, dirtiness, static
marks, smudges, or tears;
(d) false indications due to defective screens.
T-282
T-282.1 Density Limitations. The transmitted film
density through the radiographic image of the body of
the designated hole-type IQI adjacent to the essential hole
or adjacent to the essential wire of a wire-type IQI and the
area of interest shall be 1.8 minimum for single film viewing for radiographs made with an X-ray source and 2.0
minimum for radiographs made with a gamma ray source.
For composite viewing of multiple film exposures, each
film of the composite set shall have a minimum density
of 1.3. The maximum density shall be 4.0 for either single
or composite viewing. A tolerance of 0.05 in density is allowed for variations between densitometer readings.
T-282.2 Density Variation.
(a) The density of the radiograph anywhere through
the area of interest shall not
(1) vary by more than minus 15% or plus 30% from
the density through the body of the designated hole-type
IQI adjacent to the essential hole or adjacent to the essential wire of a wire-type IQI, and
(2) exceed the minimum/maximum allowable density ranges specified in T-282.1
When calculating the allowable variation in density, the
calculation may be rounded to the nearest 0.1 within the
range specified in T-282.1.
(b) When the requirements of (a) above are not met,
then an additional IQI shall be used for each exceptional
area or areas and the radiograph retaken.
(c) When shims are used with hole-type IQIs, the plus
30% density restriction of (a) above may be exceeded,
and the minimum density requirements of T-282.1 do
not apply for the IQI, provided the required IQI sensitivity
of T-283.1 is met.
T-277.3 Shims Under Hole-Type IQIs. For welds, a
shim of material radiographically similar to the weld metal shall be placed between the part and the IQI, if needed,
so that the radiographic density throughout the area of interest is no more than minus 15% from (lighter than) the
radiographic density through the designated IQI adjacent
to the essential hole.
The shim dimensions shall exceed the IQI dimensions
such that the outline of at least three sides of the IQI image shall be visible in the radiograph.
T-280
T-281
RADIOGRAPHIC DENSITY
T-283
IQI SENSITIVITY
T-283.1 Required Sensitivity. Radiography shall be ð21Þ
performed with a technique of sufficient sensitivity to display the designated hole-type IQI image (including applicable material group identification notches) and the
essential hole, or the essential wire of a wire-type IQI.
The radiographs shall also display the IQI identifying
numbers and letters. If the designated hole-type IQI image
(including applicable material group identification
notches) and essential hole, or essential wire of a wiretype IQI, do not show on any film in a multiple film technique, but do show in composite film viewing, interpretation shall be permitted only by composite film viewing.
EVALUATION
QUALITY OF RADIOGRAPHS
All radiographs shall be free from mechanical, chemical,
or other blemishes to the extent that they do not mask
and are not confused with the image of any discontinuity
in the area of interest of the object being radiographed.
Such blemishes include, but are not limited to:
(a) fogging;
48
ASME BPVC.V-2021
the radiograph review form documentation shall accompany the radiographs. Acceptance shall be completed
prior to presentation of the radiographs and accompanying documentation to the Inspector.
For wire-type IQIs, the essential wire shall be visible
within the area of interest representing the thickness
used for determining the essential wire, inclusive of the
allowable density variations described in T-282.2.
T-283.2 Equivalent Hole-Type IQI Sensitivity. A
thinner or thicker hole-type IQI than the designated IQI
may be substituted, provided an equivalent or better IQI
sensitivity, as listed in Table T-283, is achieved and all
other requirements for radiography are met. Equivalent
IQI sensitivity is shown in any row of Table T-283 which
contains the designated IQI and hole. Better IQI sensitivity
is shown in any row of Table T-283 which is above the
equivalent sensitivity row. If the designated IQI and hole
are not represented in the table, the next thinner IQI row
from Table T-283 may be used to establish equivalent IQI
sensitivity.
T-284
T-290
T-291
EXCESSIVE BACKSCATTER
EVALUATION BY MANUFACTURER
The Manufacturer shall be responsible for the review,
interpretation, evaluation, and acceptance of the completed radiographs to assure compliance with the requirements of Article 2 and the referencing Code
Section. As an aid to the review and evaluation, the radiographic technique documentation required by T-291 shall
be completed prior to the evaluation. The radiograph review form required by T-292 shall be completed during
the evaluation. The radiographic technique details and
T-292
10
12
15
17
20
25
30
35
40
50
60
80
100
120
160
200
Equivalent Hole-Type Designations
1T Hole
4T Hole
15
17
20
25
30
35
40
50
60
70
80
120
140
160
240
280
5
7
10
12
15
17
20
25
30
35
40
60
70
80
120
140
RADIOGRAPHIC TECHNIQUE
DOCUMENTATION DETAILS
RADIOGRAPH REVIEW FORM
The Manufacturer shall be responsible for the preparation of a radiograph review form. As a minimum, the following information shall be provided.
(a) a listing of each radiograph location
(b) the information required in T-291, by inclusion of
the information on the review form or by reference to
an attached radiographic technique details sheet
(c) evaluation and disposition of the material(s) or
weld(s) examined
(d) identification (name) of the Manufacturer’s representative who performed the final acceptance of the
radiographs
(e) date of Manufacturer’s evaluation
Table T-283
Equivalent Hole-Type IQI Sensitivity
Hole-Type Designation
2T Hole
DOCUMENTATION
The organization shall prepare and document the
radiographic technique details. As a minimum, the following information shall be provided.
(a) the requirements of Article 1, T-190(a)
(b) identification as required by T-224
(c) the dimensional map (if used) of marker placement
in accordance with T-275.3
(d) number of exposures
(e) X-ray voltage or isotope type used
(f) source size (F in T-274.1)
(g) base material type and thickness, weld thickness,
weld reinforcement thickness, as applicable
(h) source-to-object distance (D in T-274.1)
(i) distance from source side of object to film (d in
T-274.1)
(j) film manufacturer and their assigned type/
designation
(k) number of film in each film holder/cassette
(l) single- or double-wall exposure
(m) single- or double-wall viewing
If a light image of the “B,” as described in T-223, appears on a darker background of the radiograph, protection from backscatter is insufficient and the radiograph
shall be considered unacceptable. A dark image of the
“B” on a lighter background is not cause for rejection.
T-285
ARTICLE 2
49
ð21Þ
ARTICLE 2
ASME BPVC.V-2021
MANDATORY APPENDIX I
IN-MOTION RADIOGRAPHY
I-210
F = source size: the maximum projected dimension of
the radiating source (or focal spot) in the plane perpendicular to the distance b + c from the weld
being radiographed
w = beam width at the source side of the weld measured in the direction of motion
SCOPE
In-motion radiography is a technique of film radiography where the object being radiographed and/or the
source of radiation is in motion during the exposure.
In-motion radiography may be performed on weldments when the following modified provisions to those
in Article 2 are satisfied.
This Appendix is not applicable to computed radiographic (CR) or digital radiographic (DR) techniques.
I-220
GENERAL REQUIREMENTS
I-223
BACKSCATTER DETECTION SYMBOL
LOCATION
NOTE: Use consistent units.
CALIBRATION
I-263
BEAM WIDTH
EXAMINATION
I-274
GEOMETRIC AND IN-MOTION
UNSHARPNESS
I-274.1 Geometric Unsharpness. Geometric unsharpness for in-motion radiography shall be determined
in accordance with T-274.1.
(a) For longitudinal welds the lead symbol “B” shall be
attached to the back of each film cassette or at approximately equal intervals not exceeding 36 in. (914 mm)
apart, whichever is smaller.
(b) For circumferential welds, the lead symbol “B” shall
be attached to the back of the film cassette in each quadrant or spaced no greater than 36 in. (914 mm), whichever is smaller.
(c) The lead symbol “B” shall be placed in a location so
that it would appear within an area on the radiograph
that meets the requirements of T-282.
I-260
I-270
I-274.2 In-Motion Unsharpness. In-motion unsharpness of the radiograph shall be determined in accordance
with:
where
D = distance from source of radiation to weld being
radiographed
d = distance from source side of the weld being radiographed to the film
U M = in-motion unsharpness
w = beam width at the source side of the weld measured in the direction of motion determined as specified in I-263
The beam width shall be controlled by a metal diaphragm such as lead. The diaphragm for the energy selected shall be at least 10 half value layers thick.
The beam width as shown in Figure I-263 shall be determined in accordance with:
NOTE: Use consistent units.
I-274.3 Unsharpness Limitations. Recommended
maximum values for geometric unsharpness and inmotion unsharpness are provided in T-274.2.
I-275
LOCATION MARKERS
Location markers shall be placed adjacent to the weld
at the extremity of each film cassette and also at approximately equal intervals not exceeding 15 in. (381 mm).
where
a = slit width in diaphragm in direction of motion
b = distance from source to the weld side of the
diaphragm
c = distance from weld side of the diaphragm to the
source side of the weld surface
I-277
PLACEMENT AND NUMBER OF IQIS
(a) For longitudinal welds, hole IQIs shall be placed adjacent to and on each side of the weld seam, or on the
weld seam at the beginning and end of the weld seam,
50
ASME BPVC.V-2021
ARTICLE 2
Figure I-263
Beam Width Determination
when used, shall be placed on the weld seam so that the
length of the wires is across the length of the weld and
spaced as indicated above for hole IQIs.
and thereafter at approximately equal intervals not exceeding 36 in. (914 mm) or for each film cassette. Wire
IQIs, when used, shall be placed on the weld seam so that
the length of the wires is across the length of the weld and
spaced as indicated above for hole IQIs.
(b) For circumferential welds, hole IQIs shall be placed
adjacent to and on each side of the weld seam or on the
weld seam in each quadrant or spaced no greater than
36 in. (914 mm) apart, whichever is smaller. Wire IQIs,
I-279
REPAIRED AREA
When radiography of a repaired area is required, the
length of the film used shall be at least equal to the length
of the original location marker interval.
51
ARTICLE 6
ASME BPVC.V-2021
ARTICLE 6
LIQUID PENETRANT EXAMINATION
ð21Þ
T-610
SCOPE
T-621.3 Minimum and Maximum Step Times. The
written procedure shall have minimum and maximum
times for the applicable examination steps listed in Table
T-621.3.
When this Article is specified by a referencing Code
Section, the liquid penetrant method described in this
Article shall be used together with Article 1, General Requirements. Definitions of terms used in this Article appear in Article 1, Mandatory Appendix I, I-121.3, PT —
Liquid Penetrants.
T-620
T-630
The term penetrant materials, as used in this Article, is
intended to include all penetrants, emulsifiers, solvents or
cleaning agents, developers, etc., used in the examination
process. The descriptions of the liquid penetrant classifications and material types are provided in SE-165 of
Article 24.
GENERAL
The liquid penetrant examination method is an effective means for detecting discontinuities which are open
to the surface of nonporous metals and other materials.
Typical discontinuities detectable by this method are
cracks, seams, laps, cold shuts, laminations, and porosity.
T-640
T-641
In principle, a liquid penetrant is applied to the surface
to be examined and allowed to enter discontinuities. All
excess penetrant is then removed, the part is dried, and
a developer is applied. The developer functions both as
a blotter to absorb penetrant that has been trapped in discontinuities, and as a contrasting background to enhance
the visibility of penetrant indications. The dyes in penetrants are either color contrast (visible under white light)
or fluorescent (visible under ultraviolet light).
MISCELLANEOUS REQUIREMENTS
CONTROL OF CONTAMINANTS
The user of this Article shall obtain certification of contaminant content for all liquid penetrant materials used
on nickel base alloys, austenitic or duplex stainless steels,
and titanium. These certifications shall include the penetrant manufacturers’ batch numbers and the test results
obtained in accordance with Mandatory Appendix II of
this Article. These records shall be maintained as required by the referencing Code Section.
T-642
T-621
EQUIPMENT
WRITTEN PROCEDURE REQUIREMENTS
SURFACE PREPARATION
(a) In general, satisfactory results may be obtained
when the surface of the part is in the as-welded, as-rolled,
as-cast, or as-forged condition. Surface preparation by
grinding, machining, or other methods may be necessary
where surface irregularities could mask indications.
(b) Prior to each liquid penetrant examination, the surface to be examined and all adjacent areas within at least
1 in. (25 mm) shall be dry and free of all dirt, grease, lint,
scale, welding flux, weld spatter, paint, oil, and other extraneous matter that could obscure surface openings or
otherwise interfere with the examination.
(c) Typical cleaning agents which may be used are detergents, organic solvents, descaling solutions, and paint
removers. Degreasing and ultrasonic cleaning methods
may also be used.
(d) Cleaning solvents shall meet the requirements of
T-641. The cleaning method employed is an important
part of the examination process.
T-621.1 Requirements. Liquid penetrant examination shall be performed in accordance with a written procedure which shall as a minimum, contain the
requirements listed in Table T-621.1. The written procedure shall establish a single value, or range of values, for
each requirement.
T-621.2 Procedure Qualification. When procedure
qualification is specified by the referencing Code Section,
a change of a requirement in Table T-621.1 identified as
an essential variable shall require requalification of the
written procedure by demonstration. A change of a requirement identified as a nonessential variable does not
require requalification of the written procedure. All
changes of essential or nonessential variables from those
specified within the written procedure shall require revision of, or an addendum to, the written procedure.
226
ASME BPVC.V-2021
ARTICLE 6
Table T-621.1
Requirements of a Liquid Penetrant Examination Procedure
Requirement
Essential Variable
Nonessential
Variable
Identification of and any change in type or family group of penetrant materials including
developers, emulsifiers, etc.
Surface preparation (finishing and cleaning, including type of cleaning solvent)
Method of applying penetrant
Method of removing excess surface penetrant
Hydrophilic or lipophilic emulsifier concentration and dwell time in dip tanks and agitation
time for hydrophilic emulsifiers
Hydrophilic emulsifier concentration in spray applications
Method of applying developer
Minimum and maximum time periods between steps and drying aids
Decrease in penetrant dwell time
Increase in developer dwell time (Interpretation Time)
Minimum light intensity
Surface temperature outside 40°F to 125°F (5°C to 52°C) or as previously qualified
Performance demonstration, when required
Personnel qualification requirements
Materials, shapes, or sizes to be examined and the extent of examination
Post-examination cleaning technique
X
…
X
X
X
X
…
…
…
…
X
X
X
X
X
X
X
X
…
…
…
…
…
…
…
…
…
…
…
X
X
X
T-650
NOTE: Conditioning of surfaces prior to examination as required in
(a) may affect the results. See SE-165, Annex A1.
T-651
T-643
DRYING AFTER PREPARATION
TECHNIQUE
ð21Þ
TECHNIQUES
Either a color contrast (visible) penetrant or a fluorescent penetrant shall be used with one of the following
three penetrant techniques:
(a) water washable
(b) post-emulsifying
(c) solvent removable
After cleaning, drying of the surfaces to be examined
shall be accomplished by normal evaporation or with
forced hot or cold air. A minimum period of time shall
be established to ensure that the cleaning solution has
evaporated prior to application of the penetrant.
Table T-621.3
Minimum and Maximum Time Limits for Steps in Penetrant Examination Procedures
Procedure Step
Drying after preparation (T-643)
Penetrant dwell (T-672)
Penetrant removal water washable/solvent removable (T-673.1/T-673.3)
Penetrant removal with lipophilic emulsifier [T-673.2(a)]
Penetrant removal with hydrophilic emulsifier [T-673.2(b)]
Prerinse
Immersion
Water-emulsifier spray
Water immersion or spray post-rinse
Drying after penetrant removal (T-674)
Solvent removal penetrants
Water-washable and post-emulsifiable penetrants
Developer application (T-675)
Developing and interpretation time (T-675.3 and T-676)
227
Minimum
Maximum
X
X
…
X
…
X
…
X
…
…
…
…
X
X
X
X
…
…
…
X
X
X
X
X
ARTICLE 6
T-652
ASME BPVC.V-2021
TECHNIQUES FOR STANDARD
TEMPERATURES
the length of the dwell time, the penetrant shall not be allowed to dry. If for any reason the penetrant does dry, the
examination procedure shall be repeated, beginning with
a cleaning of the examination surface.
As a standard technique, the temperature of the penetrant and the surface of the part to be processed shall
not be below 40°F (5°C) nor above 125°F (52°C) throughout the examination period. Local heating or cooling is
permitted provided the part temperature remains in the
range of 40°F to 125°F (5°C to 52°C) during the examination. Where it is not practical to comply with these temperature limitations, other temperatures and times may
be used, provided the procedures are qualified as specified in T-653.
T-653
T-673
After the specified penetration (dwell) time has
elapsed, any penetrant remaining on the surface shall
be removed, taking care to minimize removal of penetrant
from discontinuities.
T-673.1 Water-Washable Penetrants.
(a) Excess water-washable penetrants shall be removed with a water spray. The water pressure shall not
exceed 50 psi (350 kPa), and the water temperature shall
not exceed 110°F (43°C).
(b) As an alternative to (a), water-washable penetrants
may be removed by wiping with a clean, dry, lint-free
cloth or absorbent paper, repeating the operation until
most traces of penetrant have been removed. The remaining traces shall be removed by wiping the surface with a
cloth or absorbent paper, lightly moistened with water.
To minimize removal of penetrant from discontinuities,
care shall be taken to avoid the use of excess water.
TECHNIQUES FOR NONSTANDARD
TEMPERATURES
When it is not practical to conduct a liquid penetrant
examination within the temperature range of 40°F
to 125°F (5°C to 52°C), the examination procedure at
the proposed lower or higher temperature range requires
qualification of the penetrant materials and processing in
accordance with Mandatory Appendix III of this Article.
T-654
TECHNIQUE RESTRICTIONS
Fluorescent penetrant examination shall not follow a
color contrast penetrant examination. Intermixing of penetrant materials from different families or different manufacturers is not permitted. A retest with water-washable
penetrants may cause loss of marginal indications due to
contamination.
T-660
T-673.2 Post-Emulsification Penetrants.
(a) Lipophilic Emulsification. After the required penetrant dwell time, the excess surface penetrant shall be
emulsified by immersing or flooding the part with the
emulsifier. Emulsification time is dependent on the type
of emulsifier and surface condition. The actual emulsification time shall be determined experimentally. After emulsification, the mixture shall be removed by immersing in
or rinsing with water. The temperature and pressure of
the water shall be as recommended by the manufacturer.
(b) Hydrophilic Emulsification. After the required penetrant dwell time, the parts may be prerinsed with water
spray or dir ectly immer sed or spr ayed with an
emulsifier–water mixture. A prerinse allows removal of
excess surface penetrant from examination objects prior
to the application of hydrophilic emulsifiers. Hydrophilic
emulsifiers work by detergent action. For immersion applications, examination objects must be mechanically
moved in the emulsifier bath or the emulsifier must be
agitated by air bubbles, so that with either method, the
emulsifier comes in contact with the penetrant coating.
With immersion, the concentration of the emulsifier–
water bath shall be as recommended by the manufacturer. For spray applications, all part surfaces shall be
uniformly sprayed with an emulsifier–water mixture.
With spray applications, the emulsifier concentration
shall be in accordance with the manufacturer’s recommendations, but shall be no greater than 5%. The final
step after emulsification is a water immersion or a water
spray post-rinse to remove the emulsified penetrant. All
dwell times should be kept to a minimum and shall be
not more than 2 min unless a longer time is qualified on
a specific part. The pressures (water emulsifier and water
CALIBRATION
Light meters, both visible and fluorescent (black) light
meters, shall be calibrated at least once a year or whenever the meter has been repaired. If meters have not been
in use for one year or more, calibration shall be done before being used.
T-670
T-671
EXAMINATION
PENETRANT APPLICATION
The penetrant may be applied by any suitable means,
such as dipping, brushing, or spraying. If the penetrant
is applied by spraying using compressed-air-type apparatus, filters shall be placed on the upstream side near the
air inlet to preclude contamination of the penetrant by
oil, water, dirt, or sediment that may have collected in
the lines.
T-672
EXCESS PENETRANT REMOVAL
PENETRATION (DWELL) TIME
Penetration (dwell) time is critical. The minimum penetration time shall be as required in Table T-672 or as
qualified by demonstration for specific applications. The
maximum dwell time shall not exceed 2 hr or as qualified
by demonstration for specific applications. Regardless of
228
ASME BPVC.V-2021
ARTICLE 6
Table T-672
Minimum Dwell Times
Dwell Times
[Note (1)], (minutes)
Material
Aluminum, magnesium, steel, brass and
bronze, titanium and high-temperature
alloys
Carbide-tipped tools
Plastic
Glass
Ceramic
Form
Type of Discontinuity
Castings and welds
Cold shuts, porosity, lack of
fusion, cracks (all forms)
Wrought materials —
extrusions, forgings, plate
Brazed or welded
All forms
All forms
All forms
Laps, cracks
Lack of fusion, porosity, cracks
Cracks
Cracks
Cracks
Penetrant
5
10
5
5
5
5
NOTE:
(1) For temperature range from 50°F to 125°F (10°C to 52°C). For temperatures from 40°F (5°C) up to 50°F (10°C), minimum penetrant dwell
time shall be 2 times the value listed.
spray) and temperatures (water and emulsifier) shall be
in accordance with the requirements for water-washable
penetrants.
With color contrast penetrants, only a wet developer
shall be used. With fluorescent penetrants, a wet or dry
developer may be used.
NOTE: Additional information may be obtained from SE-165.
T-675.1 Dry Developer Application. Dry developer
shall be applied only to a dry surface by a soft brush, hand
powder bulb, powder gun, or other means, provided the
powder is dusted evenly over the entire surface being
examined.
T-673.3 Solvent Removable Penetrants. Excess solvent removable penetrants shall be removed by wiping
with a clean, dry, lint-free cloth or absorbent paper, repeating the operation until most traces of penetrant have
been removed. The remaining traces shall be removed by
wiping the surface with cloth or absorbent paper, lightly
moistened with solvent. To minimize removal of penetrant from discontinuities, care shall be taken to avoid
the use of excess solvent.
T-675.2 Wet Developer Application. Prior to applying suspension type wet developer to the surface, the developer must be thoroughly agitated to ensure adequate
dispersion of suspended particles.
(a) Aqueous Developer Application. Aqueous developer
may be applied to either a wet or dry surface. It shall be
applied by dipping, brushing, spraying, or other means,
provided a thin coating is obtained over the entire surface
being examined. Drying time may be decreased by using
warm air, provided the surface temperature of the part
is not raised above 125°F (52°C). Blotting is not
permitted.
(b) Nonaqueous Developer Application. Nonaqueous developers shall be applied by spraying, except where safety
or restricted access preclude it. Under such conditions,
developer may be applied by brushing. For waterwashable or post-emulsifiable penetrants, the developer
shall be applied to a dry surface. For solvent removable
penetrants, the developer may be applied as soon as practical after excess penetrant removal. Drying shall be by
normal evaporation.
WARNING: Flushing the surface with solvent, following the application of the penetrant and prior to developing, is prohibited.
T-674
DRYING AFTER EXCESS PENETRANT
REMOVAL
(a) For the water-washable or post-emulsifying technique, the surfaces may be dried by blotting with clean
materials or by using circulating air, provided the temperature of the surface is not raised above 125°F (52°C).
(b) For the solvent removable technique, the surfaces
may be dried by normal evaporation, blotting, wiping,
or forced air.
T-675
DEVELOPING
T-675.3 Developing Time. Developing time for final
interpretation begins immediately after the application
of a dry developer or as soon as a wet developer coating
is dry.
The developer shall be applied as soon as possible after
penetrant removal; the time interval shall not exceed that
established in the procedure. Insufficient coating thickness may not draw the penetrant out of discontinuities;
conversely, excessive coating thickness may mask
indications.
229
ARTICLE 6
T-676
ASME BPVC.V-2021
INTERPRETATION
(f) The UV-A light intensity shall be measured with a
UV-A light meter prior to use, whenever the light’s power
source is interrupted or changed, and at the completion of
the examination or series of examinations.
(g) Mercury vapor arc lamps produce UV-A wavelengths mainly at a peak wavelength of 365 nm for inducing fluorescence. Light-emitting diode (LED) UV-A
sources using a single UV-A LED or an array of UV-A LEDs
shall have emission characteristics comparable to those of
other UV-A sources. LED UV-A sources shall meet the requirements of SE-2297 and SE-3022. LED UV-A light
sources shall be certified as meeting the requirements
of SE-3022 and/or ASTM E3022.
T-676.1 Final Interpretation. Final interpretation
shall be made not less than 10 min nor more than
60 min after the requirements of T-675.3 are satisfied, unless otherwise qualified under T-653. If bleed-out does
not alter the examination results, longer periods are permitted. If the surface to be examined is large enough to
preclude complete examination within the prescribed or
established time, the examination shall be performed in
increments.
T-676.2 Characterizing Indication(s). The type of
discontinuities are difficult to evaluate if the penetrant
diffuses excessively into the developer. If this condition
occurs, close observation of the formation of indication
(s) during application of the developer may assist in characterizing and determining the extent of the indication(s).
T-677
POST-EXAMINATION CLEANING
When post-examination cleaning is required by the
procedure, it should be conducted as soon as practical
after Evaluation and Documentation using a process that
does not adversely affect the part.
T-676.3 Color Contrast Penetrants. With a color
contrast penetrant, the developer forms a reasonably uniform white coating. Surface discontinuities are indicated
by bleed-out of the penetrant which is normally a deep
red color that stains the developer. Indications with a
light pink color may indicate excessive cleaning. Inadequate cleaning may leave an excessive background making interpretation difficult. Illumination (natural or
supplemental white light) of the examination surface is
required for the evaluation of indications. The minimum
light intensity shall be 100 fc (1 076 lx). The light intensity, natural or supplemental white light source, shall be
measured with a white light meter prior to the evaluation
of indications or a verified light source shall be used. Verification of light sources is required to be demonstrated
only one time, documented, and maintained on file.
T-680
EVALUATION
(a) All indications shall be evaluated in terms of the acceptance standards of the referencing Code Section.
(b) Discontinuities at the surface will be indicated by
bleed-out of penetrant; however, localized surface irregularities due to machining marks or other surface conditions may produce false indications.
(c) Broad areas of fluorescence or pigmentation which
could mask indications of discontinuities are unacceptable, and such areas shall be cleaned and reexamined.
T-676.4 Fluorescent Penetrants. With fluorescent
penetrants, the process is essentially the same as in
T-676.3, with the exception that the examination is performed using an ultraviolet light, called UV-A light. The examination shall be performed as follows:
(a) It shall be performed in a darkened area with a maximum ambient white light level of 2 fc (21.5 lx) measured
with a calibrated white light meter at the examination
surface.
(b) Examiners shall be in a darkened area for at least
5 min prior to performing examinations to enable their
eyes to adapt to dark viewing. Glasses or lenses worn
by examiners shall not be photosensitive.
(c) The examination area shall be illuminated with
UV-A lights that operate in the range between 320 nm
and 400 nm.
(d) U V - A l i g h t s s h a l l a c h i e v e a m i n i m u m o f
1000 μW/cm2 on the surface of the part being examined
throughout the examination.
(e) Reflectors and filters should be checked and, if necessary, cleaned prior to use. Cracked or broken reflectors,
filters, glasses, or lenses shall be replaced immediately.
T-690
T-691
DOCUMENTATION
RECORDING OF INDICATIONS
T-691.1 Nonrejectable Indications. Nonrejectable indications shall be recorded as specified by the referencing
Code Section.
T-691.2 Rejectable Indications. Rejectable indications shall be recorded. As a minimum, the type of indications (linear or rounded), location and extent (length or
diameter or aligned) shall be recorded.
T-692
EXAMINATION RECORDS
For each examination, the following information shall
be recorded:
(a) the requirements of Article 1, T-190(a);
(b) liquid penetrant type (visible or fluorescent);
(c) type (number or letter designation) of each penetrant, penetrant remover, emulsifier, and developer used;
(d) map or record of indications per T-691;
(e) material and thickness, and;
(f) lighting equipment.
230
ASME BPVC.V-2021
ARTICLE 6
MANDATORY APPENDIX II
CONTROL OF CONTAMINANTS FOR LIQUID PENETRANT
EXAMINATION
II-610
SCOPE
SE-165, Annex 2 for chlorine and SE-165, Annex 3 for
fluorine. The total chlorine and fluorine content shall
not exceed 0.1% by weight.
This Appendix contains requirements for the control of
contaminant content for all liquid penetrant materials
used on nickel base alloys, austenitic stainless steels,
and titanium.
II-640
II-641
II-643
(a) For water used in precleaning or as part of processes that involve water, if potable water (e.g., drinking,
bottled, distilled, or deionized water) is used, it is not required to be analyzed for chlorine and sulfur.
(b) Any other type of water used that does not meet the
requirements of (a) above shall be analyzed for chlorine
in accordance with ASTM D1253 and for sulfur in accordance with SD-516. The chlorine content shall not exceed
0.1% by weight and the sulfur content shall not exceed
0.1% by weight.
REQUIREMENTS
NICKEL BASE ALLOYS
When examining nickel base alloys, all penetrant materials shall be analyzed individually for sulfur content in
accordance with SE-165, Annex 4. Alternatively, the material may be decomposed in accordance with SD-129 and
analyzed in accordance with SD-516. The sulfur content
shall not exceed 0.1% by weight.
II-642
WATER
AUSTENITIC OR DUPLEX STAINLESS
STEEL AND TITANIUM
II-690
When examining austenitic or duplex stainless steel
and titanium, all penetrant materials shall be analyzed individually for chlorine and fluorine content in accordance
with SE-165, Annex 4. Alternatively, the material may be
decomposed and analyzed in accordance with SD-808 or
DOCUMENTATION
Certifications obtained on penetrant materials shall include the penetrant manufacturers’ batch numbers and
the test results obtained in accordance with II-640. These
records shall be maintained as required by the referencing Code Section.
231
ARTICLE 6
ASME BPVC.V-2021
MANDATORY APPENDIX III
QUALIFICATION TECHNIQUES FOR EXAMINATIONS AT
NONSTANDARD TEMPERATURES
SCOPE
range. The indications of cracks shall be compared between blocks “A” and “B.” If the indications obtained under the proposed conditions on block “B” are essentially
the same as obtained on block “A” during examination
at 40°F to 125°F (5°C to 52°C), the proposed procedure
shall be considered qualified for use. A procedure qualified at a temperature lower than 40°F (5°C) shall be qualified from that temperature to 40°F (5°C).
When a liquid penetrant examination cannot be conducted within the standard temperature range of 40°F
to 125°F (5°C to 52°C), the temperature of the examination shall be qualified in accordance with this Appendix.
MATERIALS
III-641.2 Temperature Greater Than 125°F (52°C). If
the proposed temperature for the examination is above
125°F (52°C), block “B” shall be held at this temperature
throughout the examination. The indications of cracks
shall be compared as described in III-641.1 while block
“B” is at the proposed temperature and block “A” is at
the 40°F to 125°F (5°C to 52°C) temperature range.
A liquid penetrant comparator block shall be made as
follows. The liquid penetrant comparator blocks shall be
made of aluminum, ASTM B209, Type 2024, 3/8 in.
(10 mm) thick, and should have approximate face dimensions of 2 in. × 3 in. (50 mm × 75 mm). At the center of
each face, an area approximately 1 in. (25 mm) in diameter shall be marked with a 950°F (510°C) temperatureindicating crayon or paint. The marked area shall be
heated with a blowtorch, a Bunsen burner, or similar device to a temperature between 950°F (510°C) and 975°F
(524°C). The specimen shall then be immediately
quenched in cold water, which produces a network of fine
cracks on each face.
The block shall then be dried by heating to approximately 300°F (149°C). After cooling, the block shall be
cut in half. One-half of the specimen shall be designated
block “A” and the other block “B” for identification in subsequent processing. Figure III-630 illustrates the comparator blocks “A” and “B.” As an alternate to cutting the
block in half to make blocks “A” and “B,” separate blocks
2 in. × 3 in. (50 mm × 75 mm) can be made using the heating and quenching technique as described above. Two
comparator blocks with closely matched crack patterns
may be used. The blocks shall be marked “A” and “B.”
III-640
III-641
3 in. (75 mm)
Figure III-630
Liquid Penetrant Comparator
Scribe
line
11/2 in.
(39 mm)
III-630
11/2 in.
(39 mm)
III-610
2 in.
(50 mm)
3/ in.
8
(10 mm)
REQUIREMENTS
COMPARATOR APPLICATION
B
III-641.1 Temperature Less Than 40°F (5°C). If it is
desired to qualify a liquid penetrant examination procedure at a temperature of less than 40°F (5°C), the proposed procedure shall be applied to block “B” after the
block and all materials have been cooled and held at the
proposed examination temperature until the comparison
is completed. A standard procedure which has previously
been demonstrated as suitable for use shall be applied to
block “A” in the 40°F to 125°F (5°C to 52°C) temperature
A
GENERAL NOTE: Dimensions given are for guidance only and are
not critical.
232
ASME BPVC.V-2021
ARTICLE 6
indications on the comparator shall be demonstrated at
200°F to 400°F (93°C to 204°C) using the maximum observed dwell time.]
To qualify a procedure for temperatures above 125°F
(52°C), for penetrants normally used in the 40°F
to 125°F (5°C to 52°C) temperature range, the upper temperature limit shall be qualified and the procedure then is
usable between the qualified upper temperature and the
normal lower temperature of 40°F (5°C). [As an example,
to qualify a penetrant normally used in the 40°F to 125°F
(5°C to 52°C) temperature range at 200°F (93°C), the capability of the penetrant need only be qualified for 40°F
to 200°F (5°C to 93°C) using the normal range dwell
times.]
The temperature range can be any range desired by the
user. For a high-temperature penetrant not normally used
in the 40°F to 125°F (5°C to 52°C) temperature range, the
capability of a penetrant to reveal indications on the comparator shall be demonstrated at both the lower and
upper temperatures. [As an example, to qualify a hightemperature penetrant for use from 200°F to 400°F
(93°C to 204°C), the capability of the penetrant to reveal
III-641.3 Alternate Techniques for Color Contrast
Penetrants. As an alternate to the requirements of
III-641.1 and III-641.2, when using color contrast penetrants, it is permissible to use a single comparator block
for the standard and nonstandard temperatures and to
make the comparison by photography.
(a) When the single comparator block and photographic technique is used, the processing details (as applicable) described in III-641.1 and III-641.2 apply. The
block shall be thoroughly cleaned between the two processing steps. Photographs shall be taken after processing
at the nonstandard temperature and then after processing at the standard temperature. The indication of cracks
shall be compared between the two photographs. The
same criteria for qualification as III-641.1 shall apply.
(b) Identical photographic techniques shall be used to
make the comparison photographs.
233
ARTICLE 7
ASME BPVC.V-2021
ARTICLE 7
MAGNETIC PARTICLE EXAMINATION
T-710
SCOPE
requirements listed in Table T-721. The written procedure shall establish a single value, or range of values,
for each requirement.
When specified by the referencing Code Section, the
magnetic particle examination techniques described in
this Article shall be used. In general, this Article is in conformance with SE-709, Standard Guide for Magnetic Particle Testing. This document provides details to be
considered in the procedures used.
When this Article is specified by a referencing Code
Section, the magnetic particle method described in this
Article shall be used together with Article 1, General Requirements. Definition of terms used in this Article are
in Article 1, Mandatory Appendix I, I-121.4, MT — Magnetic Particle.
T-721.2 Procedure Qualification. When procedure
qualification is specified by the referencing Code Section,
a change of a requirement in Table T-721 identified as an
essential variable shall require requalification of the written procedure by demonstration. A change of a requirement identified as a nonessential variable does not
require requalification of the written procedure. All
changes of essential or nonessential variables from those
specified within the written procedure shall require revision of, or an addendum to, the written procedure.
T-730
T-720
GENERAL
A suitable and appropriate means for producing the
necessary magnetic flux in the part shall be employed,
using one or more of the techniques listed in and described in T-750.
The magnetic particle examination method is applied to
detect cracks and other discontinuities on the surfaces of
ferromagnetic materials. The sensitivity is greatest for
surface discontinuities and diminishes rapidly with increasing depth of discontinuities below the surface. Typical types of discontinuities that can be detected by this
method are cracks, laps, seams, cold shuts, and
laminations.
In principle, this method involves magnetizing an area
to be examined, and applying ferromagnetic particles (the
examination’s medium) to the surface. Particle patterns
form on the surface where the magnetic field is forced
out of the part and over discontinuities to cause a leakage
field that attracts the particles. Particle patterns are
usually characteristic of the type of discontinuity that is
detected.
Whichever technique is used to produce the magnetic
flux in the part, maximum sensitivity will be to linear discontinuities oriented perpendicular to the lines of flux.
For optimum effectiveness in detecting all types of discontinuities, each area is to be examined at least twice,
with the lines of flux during one examination being approximately perpendicular to the lines of flux during the
other.
T-721
EQUIPMENT
T-731
EXAMINATION MEDIUM
The finely divided ferromagnetic particles used for the
examination shall meet the following requirements.
(a) Particle Types. The particles shall be treated to impart color (fluorescent pigments, nonfluorescent pigments, or both) in order to make them highly visible
(contrasting) against the background of the surface being
examined.
(b) Particles. Dry and wet particles and suspension vehicles shall be in accordance with the applicable specifications listed in SE-709, para. 2.2.
(c) Temperature Limitations. Particles shall be used
within the temperature range limitations set by the manufacturer of the particles. Alternatively, particles may be
used outside the particle manufacturer’s recommendations providing the procedure is qualified in accordance
with Article 1, T-150 at the proposed temperature.
WRITTEN PROCEDURE REQUIREMENTS
T-721.1 Requirements. Magnetic particle examination shall be performed in accordance with a written procedure, which shall, as a minimum, contain the
234
ASME BPVC.V-2021
ARTICLE 7
Table T-721
Requirements of a Magnetic Particle Examination Procedure
Requirement
Essential Variable
Nonessential
Variable
Magnetizing technique
Magnetizing current type or amperage outside range specified by this Article or as previously
qualified
Surface preparation
Magnetic particles (fluorescent/visible, color, particle size, wet/dry)
Method of particle application
Method of excess particle removal
Minimum light intensity
Existing coatings, greater than the thickness demonstrated
Nonmagnetic surface contrast enhancement, when utilized
Performance demonstration, when required
Examination part surface temperature outside of the temperature range recommended by the
manufacturer of the particles or as previously qualified
Shape or size of the examination object
Equipment of the same type
Temperature (within those specified by manufacturer or as previously qualified)
Demagnetizing technique
Post-examination cleaning technique
Personnel qualification requirements
X
X
…
…
X
X
X
X
X
X
X
X
X
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
X
X
X
X
X
X
T-740
T-741
MISCELLANEOUS REQUIREMENTS
enhancement. Thickness measurement of this nonmagnetic surface contrast enhancement is not required.
SURFACE CONDITIONING
T-741.1
NOTE: Refer to T-150(a) for guidance for the demonstration required in T-741.1(d) and T-741.2.
Preparation.
(a) Satisfactory results are usually obtained when the
surfaces are in the as-welded, as-rolled, as-cast, or asforged conditions. However, surface preparation by
grinding or machining may be necessary where surface irregularities could mask indications due to discontinuities.
T-750
T-751
TECHNIQUE
TECHNIQUES
One or more of the following five magnetization techniques shall be used:
(a) prod technique
(b) longitudinal magnetization technique
(c) circular magnetization technique
(d) yoke technique
(e) multidirectional magnetization technique
(b) Prior to magnetic particle examination, the surface
to be examined and all adjacent areas within at least
1 in. (25 mm) shall be dry and free of all dirt, grease, lint,
scale, welding flux and spatter, oil, or other extraneous
matter that could interfere with the examination.
(c) Cleaning may be accomplished using detergents, organic solvents, descaling solutions, paint removers, vapor
degreasing, sand or grit blasting, or ultrasonic cleaning
methods.
T-752
(d) If nonmagnetic coatings are left on the part in the
area being examined, it shall be demonstrated that indications can be detected through the existing maximum coating thickness applied. When AC yoke technique is used,
the demonstration shall be in accordance with Mandatory
Appendix I of this Article.
PROD TECHNIQUE
T-752.1 Magnetizing Procedure. For the prod technique, magnetization is accomplished by portable prod
type electrical contacts pressed against the surface in
the area to be examined. To avoid arcing, a remote control
switch, which may be built into the prod handles, shall be
provided to permit the current to be applied after the
prods have been properly positioned.
T-741.2 Nonmagnetic Surface Contrast Enhancement. Nonmagnetic surface contrasts may be applied by
the examiner to uncoated surfaces, only in amounts sufficient to enhance particle contrast. When nonmagnetic
surface contrast enhancement is used, it shall be demonstrated that indications can be detected through the
T-752.2 Magnetizing Current. Direct or rectified
magnetizing current shall be used. The current shall be
100 (minimum) amp/in. (4 amp/mm) to
125 (maximum) amp/in. (5 amp/mm) of prod spacing
for sections 3/4 in. (19 mm) thick or greater. For sections
235
ARTICLE 7
ASME BPVC.V-2021
less than 3/4 in. (19 mm) thick, the current shall be
90 amp/in. (3.6 amp/mm) to 110 amp/in.
(4.4 amp/mm) of prod spacing.
(b) Parts With L/D Ratios Less Than 4 but Not Less Than
2. The magnetizing ampere-turns shall be within 10% of
the ampere-turns’ value determined as follows:
T-752.3 Prod Spacing. Prod spacing shall not exceed
8 in. (200 mm). Shorter spacing may be used to accommodate the geometric limitations of the area being examined
or to increase the sensitivity, but prod spacings of less
than 3 in. (75 mm) are usually not practical due to banding of the particles around the prods. The prod tips shall
be kept clean and dressed. If the open circuit voltage of
the magnetizing current source is greater than 25 V, lead,
steel, or aluminum (rather than copper) tipped prods are
recommended to avoid copper deposits on the part being
examined.
T-753
(c) Parts With L/D Ratios Less Than 2. Coil magnetization technique cannot be used.
(d) If the area to be magnetized extends beyond 9 in.
(225 mm) on either side of the coil’s center, field adequacy shall be demonstrated using a magnetic field indicator or artificial flaw shims per T-764.
(e) F or la r ge parts du e to s ize and sha pe, the
magnetizing current shall be 1200 ampere-turns
to 4500 ampere-turns. The field adequacy shall be demonstrated using artificial flaw shims or a pie-shaped
magnetic field indicator in accordance with T-764. A
Hall-Effect probe gaussmeter shall not be used with encircling coil magnetization techniques.
LONGITUDINAL MAGNETIZATION
TECHNIQUE
T-753.1 Magnetizing Procedure. For this technique,
magnetization is accomplished by passing current
through a multi-turn fixed coil (or cables) that is wrapped
around the part or section of the part to be examined. This
produces a longitudinal magnetic field parallel to the axis
of the coil.
T-753.3 Magnetizing Current. The current required
to obtain the necessary magnetizing field strength shall
be determined by dividing the ampere-turns obtained in
steps T-753.2(a) or T-753.2(b) by the number of turns
in the coil as follows:
If a fixed, prewound coil is used, the part shall be placed
near the side of the coil during inspection. This is of special importance when the coil opening is more than
10 times the cross-sectional area of the part.
For example, if a 5-turn coil is used and the ampereturns required are 5000, use
T-753.2 Magnetic Field Strength. Direct or rectified
current shall be used to magnetize parts examined by this
technique. The required field strength shall be calculated
based on the length L and the diameter D of the part in
accordance with (a) and (b), or as established in (d)
and (e), below. Long parts shall be examined in sections
not to exceed 18 in. (450 mm), and 18 in. (450 mm) shall
be used for the part L in calculating the required field
strength. For noncylindrical parts, D shall be the maximum cross-sectional diagonal.
T-754
CIRCULAR MAGNETIZATION TECHNIQUE
T-754.1 Direct Contact Technique.
(a) Magnetizing Procedure. For this technique, magnetization is accomplished by passing current through the
part to be examined. This produces a circular magnetic
field that is approximately perpendicular to the direction
of current flow in the part.
(b) Magnetizing Current. Direct or rectified (half-wave
rectified or full-wave rectified) magnetizing current shall
be used.
(1) The current shall be 300 amp/in. (12 A/mm) to
800 amp/in. (31 A/mm) of outer diameter.
(2) For parts with geometric shapes other than
round, the greatest cross-sectional diagonal in a plane
at right angles to the current flow shall be used in lieu
of the outer diameter in (1) above.
(3) If the current levels required for (1) cannot be obtained, the maximum current obtainable shall be used and
the field adequacy shall be demonstrated in accordance
with T-764.
(a) Parts With L/D Ratios Equal to or Greater Than 4.
The magnetizing current shall be within 10% of the
ampere-turns’ value determined as follows:
For example, a part 10 in. (250 mm) long × 2 in.
(50 mm) diameter has an L/D ratio of 5. Therefore,
236
ASME BPVC.V-2021
T-754.2
Central Conductor Technique.
ARTICLE 7
Figure T-754.2.2
The Effective Region of Examination When
Using an Offset Central Conductor
(a) Magnetizing Procedure. For this technique, a central
conductor is used to examine the internal surfaces of cylindrically or ring-shaped parts. The central conductor
technique may also be used for examining the outside surfaces of these shapes. Where large diameter cylinders are
to be examined, the conductor shall be positioned close to
the internal surface of the cylinder. When the conductor is
not centered, the circumference of the cylinder shall be
examined in increments. Field strength measurements
in accordance with T-764 shall be used, to determine
the extent of the arc that may be examined for each conductor position or the rules in (c) below may be followed.
Bars or cables, passed through the bore of a cylinder, may
be used to induce circular magnetization.
Effective
region
Central conductor
4d
d
(b) Magnetizing Current. The field strength required
shall be equal to that determined in T-754.1(b) for a
single-turn central conductor. The magnetic field will increase in proportion to the number of times the central
conductor cable passes through a hollow part. For example, if 6000 A are required to examine a part using a single
pass central conductor, then 3000 A are required when 2
passes of the through-cable are used, and 1200 A are required if 5 passes are used (see Figure T-754.2.1). When
the central conductor technique is used, magnetic field
adequacy shall be verified using a magnetic particle field
indicator in accordance with T-764.
T-755
YOKE TECHNIQUE
For this technique, alternating or direct current electromagnetic yokes, or permanent magnet yokes, shall be
used.
T-756
MULTIDIRECTIONAL MAGNETIZATION
TECHNIQUE
T-756.1 Magnetizing Procedure. For this technique,
magnetization is accomplished by high amperage power
packs operating as many as three circuits that are energized one at a time in rapid succession. The effect of these
rapidly alternating magnetizing currents is to produce an
overall magnetization of the part in multiple directions.
Circular or longitudinal magnetic fields may be generated
in any combination using the various techniques described in T-753 and T-754.
(c) Offset Central Conductor. When the conductor passing through the inside of the part is placed against an inside wall of the part, the current levels, as given in
T-754.1(b)(1) shall apply, except that the diameter used
for current calculations shall be the sum of the diameter
of the central conductor and twice the wall thickness.
The distance along the part circumference (exterior) that
is effectively magnetized shall be taken as four times the
diameter of the central conductor, as illustrated in Figure
T-754.2.2. The entire circumference shall be inspected by
rotating the part on the conductor, allowing for approximately a 10% magnetic field overlap.
T-756.2 Magnetic Field Strength. Only three phase,
full-wave rectified current shall be used to magnetize
the part. The initial magnetizing current requirements
Figure T-754.2.1
Single-Pass and Two-Pass Central Conductor Technique
237
ARTICLE 7
ASME BPVC.V-2021
T-763
for each circuit shall be established using the previously
described guidelines (see T-753 and T-754). The adequacy of the magnetic field shall be demonstrated using
artificial flaw shims or a pie-shaped magnetic particle
field indicator in accordance with T-764. A Hall-Effect
probe gaussmeter shall not be used to measure field adequacy for the multidirectional magnetization technique.
An adequate field shall be obtained in at least two nearly
perpendicular directions, and the field intensities shall be
balanced so that a strong field in one direction does not
overwhelm the field in the other direction. For areas
where adequate field strengths cannot be demonstrated,
additional magnetic particle techniques shall be used to
obtain the required two-directional coverage.
T-760
T-761
Hall-Effect probe gaussmeters used to verify magnetizing field strength in accordance with T-754 shall be calibrated at least once a year or whenever the equipment
has been subjected to a major repair, periodic overhaul,
or damage. If equipment has not been in use for a year
or more, calibration shall be done prior to first use.
T-764
MAGNETIC FIELD ADEQUACY AND
DIRECTION
T-764.1 Application. The use of magnetic field indicators, artificial shims, or Hall-Effect tangential-field
probes are only permitted when specifically referenced
by the following magnetizing techniques:
(a) Longitudinal (T-753)
(b) Circular (T-754)
(c) Multidirectional (T-756)
CALIBRATION
FREQUENCY OF CALIBRATION
T-761.1 Magnetizing Equipment.
(a) Frequency. Magnetizing equipment with an ammeter shall be calibrated at least once a year, or whenever
the equipment has been subjected to major electric repair, periodic overhaul, or damage. If equipment has not
been in use for a year or more, calibration shall be done
prior to first use.
(b) Procedure. The accuracy of the unit’s meter shall be
verified annually by equipment traceable to a national
standard. Comparative readings shall be taken for at least
three different current output levels encompassing the
usable range.
(c) Tolerance. The unit’s meter reading shall not deviate by more than ±10% of full scale, relative to the actual
current value as shown by the test meter.
T-764.2 Magnetic Field Adequacy. The applied magnetic field shall have sufficient strength to produce satisfactory indications, but shall not be so strong that it
causes masking of relevant indications by nonrelevant accumulations of magnetic particles. Factors that influence
the required field strength include the size, shape, and
material permeability of the part; the technique of magnetization; coatings; the method of particle application; and
the type and location of discontinuities to be detected.
When it is necessary to verify the adequacy of magnetic
field strength, it shall be verified by using one or more
of the following three methods.
(a) Pie-Shaped Magnetic Particle Field Indicator. The indicator, shown in Figure T-764.2(a), shall be positioned
on the surface to be examined, such that the copperplated side is away from the inspected surface. A suitable
field strength is indicated when a clearly defined line (or
lines) of magnetic particles form(s) across the copper face
of the indicator when the magnetic particles are applied
simultaneously with the magnetizing force. When a
clearly defined line of particles is not formed, the magnetizing technique shall be changed as needed. Pie-type indicators are best used with dry particle procedures.
(b) Artificial Flaw Shims. One of the shims shown in
Figure T-764.2(b)(1) or Figure T-764.2(b)(2) whose orientation is such that it can have a component perpendicular to the applied magnetic field shall be used. Shims
with linear notches shall be oriented so that at least one
notch is perpendicular to the applied magnetic field.
Shims with only circular notches may be used in any orientation. Shims shall be attached to the surface to be examined, such that the artificial flaw side of the shim is
toward the inspected surface. A suitable field strength is
indicated when a clearly defined line (or lines) of magnetic particles, representing the 30% depth flaw, appear
(s) on the shim face when magnetic particles are applied
simultaneously with the magnetizing force. When a
T-761.2 Light Meters. Light meters shall be calibrated at least once a year or whenever a meter has been
repaired. If meters have not been in use for one year or
more, calibration shall be done before being used.
T-762
GAUSSMETERS
LIFTING POWER OF YOKES
(a) The magnetizing power of yokes shall be verified
prior to use each day the yoke is used. The magnetizing
power of yokes shall be verified whenever the yoke has
been damaged or repaired.
(b) Each alternating current electromagnetic yoke shall
have a lifting power of at least 10 lb (4.5 kg) at the maximum pole spacing, with contact similar to what will be
used during the examination.
(c) Each direct current or permanent magnetic yoke
shall have a lifting power of at least 40 lb (18 kg) at the
maximum pole spacing, with contact similar to what will
be used during the examination.
(d) Each weight shall be weighed with a scale from a reputable manufacturer and stenciled with the applicable
nominal weight prior to first use. A weight need only be
verified again if damaged in a manner that could have
caused potential loss of material.
238
ASME BPVC.V-2021
T-765
Figure T-764.2(a)
Pie-Shaped Magnetic Particle Field Indicator
ARTICLE 7
WET PARTICLE CONCENTRATION AND
CONTAMINATION
Wet Horizontal Units shall have the bath concentration
and bath contamination determined by measuring its settling volume. This is accomplished through the use
of a pear-shaped centrifuge tube with a 1-mL stem
(0.05-mL divisions) for fluorescent particle suspensions
or a 1.5-mL stem (0.1-mL divisions) for nonfluorescent
suspensions (see SE-709, Appendix X5). Before sampling,
the suspension should be run through the recirculating
system for at least 30 min to ensure thorough mixing of
all particles which could have settled on the sump screen
and along the sides or bottom of the tank.
T-765.1 Concentration. Take a 100-mL portion of the
suspension from the hose or nozzle, demagnetize and allow it to settle for approximately 60 min with petroleum
distillate suspensions or 30 min with water-based
Figure T-764.2(b)(1)
Artificial Flaw Shims
0.002 in.
(0.06 mm)
A
0.75 in.
(20 mm)
clearly defined line of particles is not formed, the magnetizing technique shall be changed as needed. Shim-type
indicators are best used with wet particle procedures.
0.0006 in.
(0.015 mm)
A
NOTE: The circular shims shown in Figure T-764.2(b)(2) illustration
(b) also have flaw depths less and greater than 30%.
0.25 in.
(6 mm)
(c) Hall-Effect Tangential-Field Probe. A gaussmeter
and Hall-Effect tangential-field probe shall be used for
measuring the peak value of a tangential field. The probe
shall be positioned on the surface to be examined,
such that the maximum field strength is determined. A
suitable field strength is indicated when the measured
field is within the range of 30 G to 60 G (2.4 kAm −1
to 4.8 kAm−1) while the magnetizing force is being applied. See Article 7, Nonmandatory Appendix A.
0.005 in.
(0.125 mm)
typical
Type B
Section A–A
0.002 in.
(0.05 mm)
A
0.75 in.
(20 mm)
0.0006 in.
(0.015 mm)
A
0.5 in.
(12.5 mm)
T-764.3 Magnetic Field Direction. The direction(s)
of magnetization shall be determined by particle indications obtained using an indicator or shims as shown in
Figure T-764.2(a), Figure T-764.2(b)(1), or Figure
T-764.2(b)(2). When a clearly defined line of particles
are not formed
(a) in the desired direction, or
(b) in at least two nearly perpendicular directions for
the multidirectional technique
Type C
2 in. (50 mm)
Defect
Division
0.4 in.
(10 mm)
0.2 in.
(5 mm)
the magnetizing technique shall be changed as needed.
Type R
Section A–A
0.002 in.
(0.05 mm)
0.005 in.
(0.125 mm)
typical
0.0006 in.
(0.015 mm)
GENERAL NOTE: Above are examples of artificial flaw shims used
in magnetic particle inspection system verification (not drawn to
scale). The shims are made of low carbon steel (1005 steel foil).
The artificial flaw is etched or machined on one side of the foil to
a depth of 30% of the foil thickness.
239
ARTICLE 7
ASME BPVC.V-2021
Figure T-764.2(b)(2)
Artificial Flaw Shims
0.75 in. (typ) (19.05 mm)
0.25 in.
(6.36 mm)
0.75 in. (typ) (19.05 mm)
0.25 in.
(6.36 mm)
0.507 in. diam. O.D.
(12.88 mm)
0.507 in. diam. O.D.
(12.88 mm)
0.007 in. (typ)
(0.18 mm)
Notches:
Depth: 30% 0.0006 in.
(0.015 mm)
Shim thickness:
0.002 in. (0.05 mm)
230
Shim Type CX-230
430
Shim Type CX-430
0.007 in. (typ)
(0.18 mm)
Notches:
Depth: 30% 0.0012 in.
(0.030 mm)
Shim thickness:
0.004 in. (0.10 mm)
(a)
0.75 in. (typ) (19.05 mm)
0.75 in. (typ) (19.05 mm)
0.007 in. (type)
(0.18 mm)
0.007 in. (type)
(0.18 mm)
0.507 in. diam. O.D.
(12.88 mm)
0.507 in. diam. O.D.
(12.88 mm)
0.383 in. diam. O.D.
(9.73 mm)
0.383 in. diam. O.D.
(9.73 mm)
0.258 in. diam. O.D.
(6.55 mm)
0.258 in. diam. O.D.
(6.55 mm)
Notch depth:
20% 0.0004 in.
(0.010 mm) O.D.
30% 0.0006 in.
4-234
(0.015 mm) center
Shim Type 3C4-234
40% 0.0008 in.
Shim Thickness 0.004 in. (0.102 mm)
(0.020 mm) I.D.
Notch depth:
20% 0.0004 in.
(0.010 mm) O.D.
30% 0.0006 in.
2-234
(0.015 mm) center
Shim Type 3C2-234
40% 0.0008 in.
Shim Thickness 0.002 in. (0.05 mm)
(0.020 mm) I.D.
(b)
0.79 in. (typ) (20.06 mm)
0.235 in. (typ)
(5.97 mm)
0.79 in. (typ) (20.06 mm)
0.235 in. (typ)
(5.97 mm)
0.395 in. (typ)
(10.03 mm)
0.20 in. (typ)
(5.08 mm)
0.255 in. diam. O.D.
(6.48 mm)
0.255 in. diam.
O.D. (6.48 mm)
0.006 in. (typ)
(0.152 mm)
0.006 in. (typ)
(0.152 mm)
0.395 in. (typ)
(10.03 mm)
0.20 in. (typ)
(5.08 mm)
Notch depth:
30% 0.0006 in.
(0.015 mm)
Notch depth:
30% 0.0012 in.
(0.030 mm)
230
430
Shim Thickness 0.002 in. (0.051 mm)
Shim Type CX-230
Shim Thickness 0.004 in. (0.102 mm)
Shim Type CX4-430
(c)
240
ASME BPVC.V-2021
(b) Using the Test Ring. The test ring (see Figure
T-766.1), is circularly magnetized with full-wave rectified
AC passing through a central conductor with a 1 in.
to 11/4 in. (25 mm to 32 mm) diameter hole located in
the ring center. The conductor should have a length greater than 16 in. (400 mm). The currents used shall be 1400
A, 2500 A, and 3400 A. The minimum number of holes
shown shall be three, five, and six, respectively. The ring
edge should be examined with either black light or visible
light, depending on the type of particles involved. This
test shall be run at the three amperages if the unit will
be used at these or higher amperages. The amperage values stated shall not be exceeded in the test. If the test does
not reveal the required number of holes, the equipment
shall be taken out of service and the cause of the loss of
sensitivity determined and corrected. This test shall be
run at least once per week.
suspensions before reading. The volume settling out at
the bottom of the tube is indicative of the particle concentration in the bath.
T-765.2 Settling Volumes. For fluorescent particles,
the required settling volume is from 0.1 mL to 0.4 mL in a
100-mL bath sample and from 1.2 mL to 2.4 mL per
100 mL of vehicle for nonfluorescent particles unless
otherwise specified by the particle manufacturer. Concentration checks shall be made at least every eight hours.
T-765.3 Contamination. Both fluorescent and nonfluorescent suspensions shall be checked periodically
for contaminants such as dirt, scale, oil, lint, loose fluorescent pigment, water (in the case of oil suspensions), and
particle agglomerates which can adversely affect the performance of the magnetic particle examination process.
The test for contamination shall be performed at least
once per week.
(a) Carrier Contamination. For fluorescent baths, the liquid directly above the precipitate should be examined
with fluorescent excitation light. The liquid will have a little fluorescence. Its color can be compared with a freshly
made-up sample using the same materials or with an unused sample from the original bath that was retained for
this purpose. If the “used” sample is noticeably more
fluorescent than the comparison standard, the bath shall
be replaced.
(b) Particle Contamination. The graduated portion of
the tube shall be examined under fluorescent excitation
light if the bath is fluorescent and under visible light
(for both fluorescent and nonfluorescent particles) for
striations or bands, differences in color or appearance.
Bands or striations may indicate contamination. If the total volume of the contaminates, including bands or striations exceeds 30% of the volume magnetic particles, or if
the liquid is noticeably fluorescent, the bath shall be
replaced.
T-770
T-771
EXAMINATION
PRELIMINARY EXAMINATION
Before the magnetic particle examination is conducted,
a check of the examination surface shall be conducted to
locate any surface discontinuity openings which may not
attract and hold magnetic particles because of their width.
T-772
DIRECTION OF MAGNETIZATION
At least two separate examinations shall be performed
on each area. During the second examination, the lines of
magnetic flux shall be approximately perpendicular to
those used during the first examination. A different technique for magnetization may be used for the second
examination.
T-773
T-766
ARTICLE 7
SYSTEM PERFORMANCE OF HORIZONTAL
UNITS
METHOD OF EXAMINATION
The ferromagnetic particles used in an examination
medium can be either wet or dry, and may be either fluorescent or nonfluorescent. Examination(s) shall be done by
the continuous method.
(a) Dry Particles. The magnetizing current shall remain
on while the examination medium is being applied and
while any excess of the examination medium is removed.
(b) Wet Particles. The magnetizing current shall be
turned on after the particles have been applied. Flow of
particles shall stop with the application of current. Wet
particles applied from aerosol spray cans or pump
sprayers may be applied before and/or during magnetizing current application. Wet particles may be applied during the application of magnetizing current if they are not
applied directly to the examination area and are allowed
to flow over the examination area or are applied directly
to the examination area with low velocities insufficient to
remove accumulated particles.
The Ketos (Betz) ring specimen (see Figure T-766.1)
shall be used in evaluating and comparing the overall performance and sensitivity of both dry and wet, fluorescent
and nonfluorescent magnetic particle techniques using a
central conductor magnetization technique.
(a) Ketos (Betz) Test Ring Material. The tool steel (Ketos) ring should be machined from AISI 01 material in accordance with Figure T-766.1. Either the machined ring
or the steel blank should be annealed at 1,650°F
(900°C), cooled 50°F (28°C) per hour to 1,000°F
(540°C) and then air cooled to ambient temperature to
give comparable results using similar rings that have
had the same treatment. Material and heat treatment
are important variables. Experience indicates controlling
the softness of the ring by hardness (90 HRB to 95 HRB)
alone is insufficient.
241
ARTICLE 7
Figure T-766.1
Ketos (Betz) Test Ring
3/ in. (19 mm)
4
Typ.
125
1 2
3
4
5
6
11/4 in.
(32 mm)
5 in.
(125
mm)
7
12
D
ASME BPVC.V-2021
8
9
11 10
242
7/ in.
8
(22 mm)
Hole
Diameter [Note
(1)]
“D” [Note (2)]
1
2
3
4
5
0.07 (1.8)
0.07 (1.8)
0.07 (1.8)
0.07 (1.8)
0.07 (1.8)
0.07 (1.8)
6
7
0.07 (1.8)
0.14 (3.6)
0.21 (5.3)
0.28 (7.1)
0.35 (9.0)
0.42 (10.8) 0.49 (12.6) 0.56 (14.4) 0.63 (16.2) 0.70 (18.0) 0.77 (19.8) 0.84 (21.6)
0.07 (1.8)
8
0.07 (1.8)
9
0.07 (1.8)
10
0.07 (1.8)
11
0.07 (1.8)
12
0.07 (1.8)
GENERAL NOTES:
(a) All dimensions are ±0.03 in. (±0.8 mm) or as noted in Notes (1) and (2).
(b) In the in-text table, all dimensions are in inches, except for the parenthesized values, which are in millimeters.
(c) Material is ANSI 01 tool steel from annealed round stock.
(d) The ring may be heat treated as follows: Heat to 1,400°F to 1,500°F (760°C to 790°C). Hold at this temperature for 1 hr. Cool to a minimum rate of 40°F/hr (22°C/h) to below 1,000°F
(540°C). Furnace or air cool to room temperature. Finish the ring to RMS 25 and protect from corrosion.
NOTES:
(1) All hole diameters are ±0.005 in. (±0.1 mm.) Hole numbers 8 through 12 are optional.
(2) Tolerance on the D distance is ±0.005 in. (±0.1 mm).
ASME BPVC.V-2021
T-774
EXAMINATION COVERAGE
T-777.2 Fluorescent Magnetic Particles. With fluorescent magnetic particles, the process is essentially the
same as in T-777.1, with the exception that the examination is performed using an ultraviolet light, called UV-A
light. The examination shall be performed as follows:
(a) It shall be performed in a darkened area with a maximum ambient white light level of 2 fc (21.5 lx) measured
with a calibrated white light meter at the examination
surface.
(b) Examiners shall be in a darkened area for at least
5 min prior to performing examinations to enable their
eyes to adapt to dark viewing. Glasses or lenses worn
by examiners shall not be photosensitive.
(c) The examination area shall be illuminated with
UV-A lights that operate in the range between 320 nm
and 400 nm.
(d) U V - A l i g h t s s h a l l a c h i e v e a m i n i m u m o f
1000 μW/cm2 on the surface of the part being examined
throughout the examination.
(e) Reflectors, filters, glasses, and lenses should be
checked and, if necessary, cleaned prior to use. Cracked
or broken reflectors, filters, glasses, or lenses shall be replaced immediately.
(f) The UV-A light intensity shall be measured with a
UV-A light meter prior to use, whenever the light’s power
source is interrupted or changed, and at the completion of
the examination or series of examinations.
(g) Mercury vapor arc lamps produce UV-A wavelengths mainly at a peak wavelength of 365 nm for inducing fluorescence. LED UV-A sources using a single UV-A
LED or an array of UV-A LEDs shall have emission characteristics comparable to those of other UV-A sources. LED
UV-A sources shall meet the requirements of SE-2297 and
SE-3022. LED UV-A light sources shall be certified as
meeting the requirements of SE-3022 and/or ASTM
E3022.
All examinations shall be conducted with sufficient field
overlap to ensure 100% coverage at the required sensitivity (T-764).
T-775
RECTIFIED CURRENT
(a) Whenever direct current is required rectified current may be used. The rectified current for magnetization
shall be either three-phase (full-wave rectified) current,
or single phase (half-wave rectified) current.
(b) The amperage required with three-phase, full-wave
rectified current shall be verified by measuring the average current.
(c) The amperage required with single-phase (halfwave rectified) current shall be verified by measuring
the average current output during the conducting half cycle only.
(d) When measuring half-wave rectified current with a
direct current test meter, readings shall be multiplied by
two.
T-776
EXCESS PARTICLE REMOVAL
Accumulations of excess dry particles in examinations
shall be removed with a light air stream from a bulb or
syringe or other source of low pressure dry air. The examination current or power shall be maintained while removing the excess particles.
T-777
ARTICLE 7
INTERPRETATION
The interpretation shall identify if an indication as
false, nonrelevant, or relevant. False and nonrelevant indications shall be proven as false or nonrelevant. Interpretation shall be carried out to identify the locations of
indications and the character of the indication.
T-777.3 Fluorescent Magnetic Particles With Other
Fluorescent Excitation Wavelengths. Alternatively to
the requirements in T-777.2, the examinations may be
performed using alternate wavelength light sources
which cause fluorescence in specific particle coatings.
Any alternate light wavelength light sources and specific
particle designations used shall be qualified18 in accordance with Mandatory Appendix IV. The examination
shall be performed as follows:
(a) It shall be performed in a darkened area.
(b) Examiners shall be in a darkened area for at least
5 min prior to performing examinations to enable their
eyes to adapt to dark viewing. Glasses or lenses worn
by examiners shall not be photochromic or exhibit any
fluorescence.
(c) If the fluorescence excitation light source emits visible light intensities greater than 2 fc (21.5 lx), the examiner shall wear fluorescence-enhancing filter glasses
approved by the light source manufacturer for use with
that light source.
T-777.1 Visible (Color Contrast) Magnetic Particles.
Surface discontinuities are indicated by accumulations of
magnetic particles which should contrast with the examination surface. The color of the magnetic particles shall
be different than the color of the examination surface. Illumination (natural or supplemental white light) of the
examination surface is required for the evaluation of indications. The minimum light intensity shall be 100 fc
(1 076 lx). The light intensity, natural or supplemental
white light source, shall be measured with a white light
meter prior to the evaluation of indications or a verified
light source shall be used. Verification of light sources is
required to be demonstrated only one time, documented,
and maintained on file.
243
ARTICLE 7
ASME BPVC.V-2021
(d) The fluorescence excitation light source shall
achieve at least the minimum light intensity on the surface of the part throughout the examination as qualified
in the tests of Mandatory Appendix IV.
(e) Reflectors, filters, glasses, and lenses should be
checked and, if necessary, cleaned prior to use. Cracked
or broken reflectors, filters, glasses, or lenses shall be replaced immediately.
(f) The fluorescence excitation light intensity shall be
measured with a suitable fluorescence excitation light
meter prior to use, whenever the light’s power source is
interrupted or changed, and at the completion of the examination or series of examinations.
T-790
T-778
T-792
T-791
DOCUMENTATION
MULTIDIRECTIONAL MAGNETIZATION
TECHNIQUE SKETCH
A technique sketch shall be prepared for each different
geometry examined, showing the part geometry, cable arrangement and connections, magnetizing current for each
circuit, and the areas of examination where adequate field
strengths are obtained. Parts with repetitive geometries,
but different dimensions, may be examined using a single
sketch provided that the magnetic field strength is adequate when demonstrated in accordance with T-756.2.
DEMAGNETIZATION
RECORDING OF INDICATIONS
When residual magnetism in the part could interfere
with subsequent processing or usage, the part shall be demagnetized any time after completion of the examination.
T-792.1 Nonrejectable Indications. Nonrejectable indications shall be recorded as specified by the referencing
Code Section.
T-779
T-792.2 Rejectable Indications. Rejectable indications shall be recorded. As a minimum, the type of indications (linear or rounded), location and extent (length or
diameter or aligned) shall be recorded.
POST-EXAMINATION CLEANING
When post-examination cleaning is required, it should
be conducted as soon as practical using a process that
does not adversely affect the part.
T-780
T-793
EVALUATION
EXAMINATION RECORDS
For each examination, the following information shall
be recorded:
(a) the requirements of Article 1, T-190(a)
(b) magnetic particle equipment and type of current
(c) magnetic particles (visible or fluorescent, wet or
dry)
(d) map or record of indications per T-792
(e) material and thickness
(f) lighting equipment
(a) All indications shall be evaluated in terms of the acceptance standards of the referencing Code Section.
(b) Discontinuities on or near the surface are indicated
by retention of the examination medium. However, localized surface irregularities due to machining marks or
other surface conditions may produce false indications.
(c) Broad areas of particle accumulation, which might
mask indications from discontinuities, are prohibited,
and such areas shall be cleaned and reexamined.
244
ASME BPVC.V-2021
ARTICLE 7
MANDATORY APPENDIX I
MAGNETIC PARTICLE EXAMINATION USING THE AC YOKE
TECHNIQUE ON FERROMAGNETIC MATERIALS COATED WITH
NONFERROMAGNETIC COATINGS
I-710
SCOPE
I-721.2 Procedure Qualification/Technique Validation. When procedure qualification is specified, a change
of a requirement in Table T-721 or Table I-721 identified
as an essential variable from the specified value, or range
of values, shall require requalification of the written procedure and validation of the technique. A change of a requirement identified as an nonessential variable from the
specified value, or range of values, does not require requalification of the written procedure. All changes of essential or nonessential variables from the value, or
range of values, specified by the written procedure shall
require revision of, or an addendum to, the written
procedure.
This Appendix provides the Magnetic Particle examination methodology and equipment requirements applicable for performing Magnetic Particle examination on
ferromagnetic materials with nonferromagnetic coatings.
I-720
GENERAL
Requirements of Article 7 apply unless modified by this
Appendix.
I-722
I-721
WRITTEN PROCEDURE REQUIREMENTS
PERSONNEL QUALIFICATION
Personnel qualification requirements shall be in accordance with the referencing Code Section.
I-721.1 Requirements. Magnetic Particle examination
shall be performed in accordance with a written procedure which shall, as a minimum, contain the requirements
listed in Tables T-721 and I-721. The written procedure
shall establish a single value, or range of values, for each
requirement.
Table I-721
Requirements of AC Yoke Technique on Coated Ferritic Component
Requirement
Identification of surface configurations to be examined, including coating materials, maximum
qualified coating thickness, and product forms (e.g., base material or welded surface)
Surface condition requirements and preparation methods
Manufacturer and model of AC yoke
Manufacturer and type of magnetic particles
Minimum and maximum pole separation
Identification of the steps in performing the examination
Minimum lighting intensity and AC yoke lifting power requirements [as measured in accordance
with Technique Qualification (I-721.2)]
Methods of identifying flaw indications and discriminating between flaw indications and false or
nonrelevant indications (e.g., magnetic writing or particles held by surface irregularities)
Instructions for identification and confirmation of suspected flaw indications
Applicator other than powder blower
Method of measuring coating thickness
Recording criteria
Personnel qualification requirements unique to this technique
Reference to the procedure qualification records
245
Essential Variable
Nonessential
Variable
X
…
X
X
X
X
X
X
…
…
…
…
…
…
X
…
X
X
…
…
…
…
…
…
X
X
X
X
ARTICLE 7
I-723
ASME BPVC.V-2021
PROCEDURE/TECHNIQUE
DEMONSTRATION
shall be the same specification and heat treatment as
the coated ferromagnetic material to be examined. As
an alternative to the material requirement, other materials and heat treatments may be qualified provided:
(1) The measured yoke maximum lifting force on the
material to be examined is equal to or greater than the
maximum lifting force on the qualification specimen material. Both values shall be determined with the same or
comparable equipment and shall be documented as required in (c).
(2) All the requirements of (b) through (g) are met
for the alternate material.
(b) Examine the uncoated specimen in the most unfavorable orientation expected during the performance of
the production examination.
(c) Document the measured yoke maximum lifting
power, illumination levels, and the results.
(d) Measure the maximum coating thickness on the
item to be examined in accordance with the requirements
of I-741.
(e) Coat the specimen with the same type of coating,
conductive or nonconductive, to the maximum thickness
measured on the production item to be examined. Alternately, nonconductive shim stock may be used to simulate
nonconductive coatings.
(f) Examine the coated specimen in the most unfavorable orientation expected during the performance of the
production examination. Document the measured yoke
maximum lifting power, illumination level, and examination results.
(g) Compare the length of the indication resulting from
the longest flaw no longer than the maximum flaw size allowed by the applicable acceptance criteria, before and
after coating. The coating thickness is qualified when
the length of the indication on the coated surface is at
least 50% of the length of the corresponding indication
prior to coating.
(h) Requalification of the procedure is required for a
decrease in either the AC yoke lifting power or the illumination level, or for an increase in the coating thickness.
The procedure/technique shall be demonstrated to the
satisfaction of the Inspector in accordance with the requirements of the referencing Code Section.
I-730
EQUIPMENT
(a) The magnetizing equipment shall be in accordance
with Article 7.
(b) When the dry powder technique is used, a compressed air powder blower shall be utilized for powder
application in any position. Other applicators may be used
if qualified in the same surface position as the examination object surface. Applicators qualified for the overhead
position may be used in any other position. Applicators
qualified for the vertical position may be used in the horizontal and flat positions.
(c) Magnetic particles shall contrast with the component background.
(d) Nonconductive materials such as plastic shim stock
may be used to simulate nonconductive nonferromagnetic coatings for procedure and personnel qualification.
ð21Þ
I-740
MISCELLANEOUS REQUIREMENTS
I-741
COATING THICKNESS MEASUREMENT
The procedure demonstration and performance of examinations shall be preceded by measurement of the
coating thickness in the areas to be examined. If the coating is nonconductive, an eddy current technique or magnetic technique may be used to measure the coating
thickness. The magnetic technique shall be in accordance
with SD-7091, Standard Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings
Applied to Ferrous Metals and Nonmagnetic, Nonconductive Coatings Applied to Non-Ferrous Metals. When coatings are conductive and nonferromagnetic, a coating
thickness technique shall be used in accordance with
SD-7091. Coating measurement equipment shall be used
in accordance with the equipment manufacturer’s instructions. Coating thickness measurements shall be taken at the intersections of a 2 in. (50 mm) maximum
grid pattern over the area of examination and at least onehalf the maximum yoke leg separation beyond the examination area. The thickness shall be the mean of three separate readings within 1/4 in. (6 mm) of each intersection.
I-750
I-751
I-760
I-761
CALIBRATION
YOKE MAXIMUM LIFTING FORCE
The maximum lifting force of the AC yoke shall be determined at the actual leg separation to be used in the examination. This may be accomplished by holding the yoke
with a 10 lb (4.5 kg) ferromagnetic weight between the
legs of the yoke and adding additional weights, calibrated
on a postage or other scale, until the ferromagnetic
weight is released. The lifting power of the yoke shall
be the combined weight of the ferromagnetic material
and the added weights, before the ferromagnetic weight
was released. Other methods may be used such as a load
cell.
TECHNIQUE
TECHNIQUE QUALIFICATION
(a) A qualification specimen is required. The specimen
shall be of similar geometry or weld profile and contain at
least one linear surface indication no longer than 1/16 in.
(1.5 mm) in length. The material used for the specimen
246
ASME BPVC.V-2021
I-762
LIGHT INTENSITY MEASUREMENT
(b) Examine the coated item in accordance with the
qualified procedure.
The black light or white light intensity (as appropriate)
on the surface of the component shall be no less than that
used in the qualification test. An appropriate calibrated
black light and/or white light meter shall be used for
the tests. Minimum white light or black light intensities
shall meet the requirements of T-777.1 or T-777.2 as
applicable.
I-780
EVALUATION
If an indication greater than 50% of the maximum allowable flaw size is detected, the coating in the area of
the indication shall be removed and the examination
repeated.
I-762.1 White Light. The white light intensity shall be
measured at the inspection surface. The white light intensity for the examination shall be no less than what was
used in the qualification.
I-762.2 Black Light. The black light intensity shall be
measured at the distance from the black light in the procedure qualification and at the same distance on the examination specimen. The black light intensity shall be
no less than that used to qualify the procedure. In addition, the maximum white light intensity shall be measured
as background light on the inspection surface. The background white light for the examination shall be no greater
than what was used in the qualification.
I-770
ARTICLE 7
I-790
I-791
DOCUMENTATION
EXAMINATION RECORD
For each examination, the information required in the
records section of T-793 and the following information
shall be recorded:
(a) identification of the procedure/technique
(b) description and drawings or sketches of the qualification specimen, including coating thickness measurements and flaw dimensions
EXAMINATION
(c) equipment and materials used
(d) illumination level and yoke lifting power
(a) Surfaces to be examined, and all adjacent areas
within at least 1 in. (25 mm), shall be free of all dirt,
grease, lint, scale, welding flux and spatter, oil, and loose,
blistered, flaking, or peeling coating.
(e) qualification results, including maximum coating
thickness and flaws detected
247
ASME BPVC.V-2021
ARTICLE 9
ARTICLE 9
VISUAL EXAMINATION
T-910
T-922
SCOPE
The user of this Article shall be responsible for assigning qualified personnel to perform visual examinations to
the requirements of this Article. At the option of the organization, he may maintain one certification for each product, or several separate signed records based on the
area or type of work, or both combined. Where impractical to use specialized visual examination personnel,
knowledgeable and trained personnel, having limited
qualifications, may be used to perform specific examinations, and to sign the report forms. Personnel performing
examinations shall be qualified in accordance with requirements of the referencing Code Section.
(a) This Article contains methods and requirements for
visual examination applicable when specified by a referencing Code Section. Specific visual examination procedures required for every type of examination are not
included in this Article, because there are many applications where visual examinations are required. Some examples of these applications include nondestructive
examinations, leak testing, in-service examinations and
fabrication procedures.
(b) The requirements of Article 1, General Requirements, apply when visual examination, in accordance
with Article 9, is required by a referencing Code Section.
(c) Definitions of terms for visual examination appear
in Article 1, Mandatory Appendix I, I-121.6, VT — Visual
Examination.
T-920
T-921
PERSONNEL REQUIREMENTS
T-923
PHYSICAL REQUIREMENTS
Personnel shall have an annual vision test to assure
natural or corrected near distance acuity such that they
are capable of reading standard J-1 letters on standard
Jaeger test type charts for near vision. Equivalent near vision tests are acceptable.
GENERAL
WRITTEN PROCEDURE REQUIREMENTS
T-921.1 Requirements. Visual examinations shall be
performed in accordance with a written procedure, which
shall, as a minimum, contain the requirements listed in
Table T-921. The written procedure shall establish a single value, or range of values, for each requirement.
Table T-921
Requirements of a Visual Examination
Procedure
T-921.2 Procedure Qualification. When procedure
qualification is specified by the referencing Code Section,
a change of a requirement in Table T-921 identified as an
essential variable shall require requalification of the written procedure by demonstration. A change of a requirement identified as a nonessential variable does not
require requalification of the written procedure. All
changes of essential or nonessential variables from those
specified within the written procedure shall require revision of, or an addendum to, the written procedure.
Requirement (as Applicable)
Change in technique used
Direct to or from translucent
Direct to remote
Remote visual aids
Personnel performance
requirements, when required
Lighting intensity (decrease only)
Configurations to be examined
and base material product
forms (pipe, plate, forgings,
etc.)
Lighting equipment
Methods or tools used for surface
preparation
Equipment or devices used for a
direct technique
Sequence of examination
Personnel qualifications
T-921.3 Demonstration. The procedure shall contain
or reference a report of what was used to demonstrate
that the examination procedure was adequate. In general,
a fine line 1/32 in. (0.8 mm) or less in width, an artificial
imperfection or a simulated condition, located on the surface or a similar surface to that to be examined, may be
considered as a method for procedure demonstration.
The condition or artificial imperfection should be in the
least discernable location on the area surface to be examined to validate the procedure.
293
Essential
Variable
Nonessential
Variable
…
X
X
X
…
…
…
…
…
X
X
…
…
X
…
…
X
X
…
X
…
…
X
X
ARTICLE 9
T-930
ASME BPVC.V-2021
EQUIPMENT
Equipment used for visual examination techniques, for
example, direct, remote, or translucent, shall have the
capabilities as specified in the procedure. Capabilities include, but are not limited to viewing, magnifying, identifying, measuring, and/or recording observations in
accordance with requirements of the referencing Code
Section.
lighting. The illuminator shall provide light of an intensity
that will illuminate and diffuse the light evenly through
the area or region under examination. The ambient lighting must be so arranged that there are no surface glares
or reflections from the surface under examination and
shall be less than the light applied through the area or region under examination. The artificial light source shall
have sufficient intensity to permit “candling” any translucent laminate thickness variations.
T-950
TECHNIQUE
T-955
T-951
APPLICATIONS
Light meters shall be calibrated at least once a year or
whenever they have been repaired. If meters have not
been in use for 1 yr or more, they shall be calibrated before they are used.
Visual examination is generally used to determine such
things as the surface condition of the part, alignment of
mating surfaces, shape, or evidence of leaking. In addition,
visual examination is used to determine a composite material’s (translucent laminate) subsurface conditions.
T-952
T-980
DIRECT VISUAL EXAMINATION
T-990
T-991
DOCUMENTATION
REPORT OF EXAMINATION
(a) A written report of the examination shall contain
the following information:
(1) the date of the examination
(2) procedure identification and revision used
(3) technique used
(4) results of the examination
(5) examination personnel identity, and, when required by the referencing Code Section, qualification level
(6) identification of the part or component examined
(b) Even though dimensions, etc., were recorded in the
process of visual examination to aid in the evaluation,
there need not be documentation of each viewing or each
dimensional check. Documentation shall include all observation and dimensional checks specified by the referencing Code Section.
REMOTE VISUAL EXAMINATION
In some cases, remote visual examination may have to
be substituted for direct examination. Remote visual examination may use visual aids such as mirrors, telescopes,
borescopes, fiber optics, cameras, or other suitable instruments. Such systems shall have a resolution capability
and light intensity at least equivalent to that obtainable
by direct visual observation.
T-954
EVALUATION
(a) All examinations shall be evaluated in terms of the
acceptance standards of the referencing Code Section.
(b) An examination checklist shall be used to plan visual examination and to verify that the required visual observations were performed. This checklist establishes
minimum examination requirements and does not indicate the maximum examination which the Manufacturer
may perform in process.
Direct visual examination may usually be made when
access is sufficient to place the eye within 24 in.
(600 mm) of the surface to be examined and at an angle
not less than 30 deg to the surface to be examined. Mirrors may be used to improve the angle of vision, and aids
such as a magnifying lens may be used to assist examinations. Illumination (natural or supplemental white light)
of the examination surface is required for the specific
part, component, vessel, or section thereof being examined. The minimum light intensity shall be 100 fc
(1 076 lx). The light intensity, natural or supplemental
white light source, shall be measured with a white light
meter prior to the examination or a verified light source
shall be used. Verification of light sources is required to
be demonstrated only one time, documented, and maintained on file.
T-953
LIGHT METER CALIBRATION
TRANSLUCENT VISUAL EXAMINATION
Translucent visual examination is a supplement of direct visual examination. The method of translucent visual
examination uses the aid of artificial lighting, which can
be contained in an illuminator that produces directional
T-993
RECORD MAINTENANCE
Records shall be maintained as required by the referencing Code Section.
294
ASME BPVC.V-2021
ARTICLE 10
ARTICLE 10
LEAK TESTING
T-1010
SCOPE
T-1020
T-1021
This Article describes methods and requirements for
the performance of leak testing.
(a) When a leak testing method or technique of Article
10 is specified by a referencing Code Section, the leak test
method or technique shall be used together with Article
1, General Requirements.
(b) Definition of terms used in this Article are in Article
1, Mandatory Appendix I, I-121.7, LT — Leak Testing.
(c) The test methods or techniques of these methods
can be used for the location of leaks or the measurement
of leakage rates.
The specific test method(s) or technique(s) and Glossary of Terms of the methods in this Article are described
in Mandatory Appendices I through X of Article 10 as
follows:
Mandatory Appendix I — Bubble Test — Direct Pressure Technique
Mandatory Appendix II — Bubble Test — Vacuum Box
Technique
Mandatory Appendix III — Halogen Diode Detector
Probe Test
Mandatory Appendix IV — Helium Mass Spectrometer
Test — Detector Probe Technique
Mandatory Appendix V — Helium Mass Spectrometer
Test — Tracer Probe Technique
Mandatory Appendix VI — Pressure Change Test
Mandatory Appendix VIII — Thermal Conductivity Detector Probe Test
Mandatory Appendix IX — Helium Mass Spectrometer
Test — Hood Technique
Mandatory Appendix X — Ultrasonic Leak Detector
Test
Mandatory Appendix XI — Helium Mass Spectrometer
— Helium-Filled-Container Leakage Rate Test
Nonmandatory Appendix A — Supplementary Leak
Testing Equation Symbols
GENERAL
WRITTEN PROCEDURE REQUIREMENTS
T-1021.1 Requirements. Leak testing shall be performed in accordance with a written procedure, which
shall, as a minimum, contain the requirements listed in
the applicable Appendices, paras. I-1021 through
X-1021 and Tables I-1021 through X-1021. The written
procedure shall establish a single value, or range of values, for each requirement.
T-1021.2 Modification of Requirements. Article 10
contains test techniques; therefore, there are requirements that cannot be modified by the organization
through the demonstration process per T-150. Only those
requirements listed in Tables I-1021 through X-1021
may be so modified by demonstration.
T-1021.3 Procedure Qualification. When procedure
qualification is specified by the referencing Code Section,
a change of a requirement in the applicable Appendix
Tables I-1021 through X-1021 identified as an essential
variable shall require requalification of the written procedure by demonstration. A change of a requirement identified as a nonessential variable does not require
requalification of the written procedure. All changes of essential and nonessential elements from those specified
within the written procedure shall require revision of,
or an addendum to, the written procedure.
T-1022
REFERENCING CODE
For the leak testing method(s) or technique(s) specified by the referencing Code, the referencing Code Section
shall then be consulted for the following:
(a) personnel qualification/certification
(b) technique(s)/calibration standards
(c) extent of examination
(d) acceptable test sensitivity or leakage rate
(e) report requirements
(f) retention of records
295
ARTICLE 10
T-1030
T-1031
ASME BPVC.V-2021
EQUIPMENT
T-1044
Unless specified in the applicable Mandatory Appendix
of this Article or by the referencing Code Section, components that are to be pressure-leak tested shall not be
tested at a pressure exceeding 25% of the Design
Pressure.
GAGES
(a) Gage Range. When dial indicating and recording
pressure gage(s) are used in leak testing, they should preferably have the dial(s) graduated over a range of approximately double the intended maximum pressure,
but in no case shall the range be less than 11/2 nor more
than four times that pressure. These range limits do not
apply to dial indicating and recording vacuum gages.
Range requirements for other types of gages given in an
applicable Mandatory Appendix shall be as required by
that Appendix.
(b) Gage Location. When components are to be pressure/vacuum leak tested, the dial indicating gage(s) shall
be connected to the component or to the component from
a remote location, with the gage(s) readily visible to the
operator controlling the pressure/vacuum throughout
the duration of pressurizing, evacuating, testing, and depressurizing or venting of the component. For large vessels or systems where one or more gages are specified
or required, a recording type gage is recommended, and
it may be substituted for one of the two or more indicating type gages.
(c) When other types of gage(s) are required by an applicable Mandatory Appendix, they may be used in conjunction with or in place of dial indicating or recording
type gages.
T-1040
T-1041
T-1050
T-1051
T-1052
PRELIMINARY LEAK TEST
TEST SEQUENCE
It is recommended that leak testing be performed before hydrostatic or hydropneumatic testing.
T-1060
T-1061
CALIBRATION
PRESSURE/VACUUM GAGES
(a) All dial indicating and recording type gages used
shall be calibrated against a standard deadweight tester,
a calibrated master gage, or a mercury column, and recalibrated at least once a year, when in use, unless specified
differently by the referencing Code Section or Mandatory
Appendix. All gages used shall provide results accurate to
within the Manufacturer’s listed accuracy and shall be recalibrated at any time that there is reason to believe they
are in error.
(b) When other than dial indicating or recording type
gages are required by an applicable Mandatory Appendix,
they shall be calibrated as required by that Mandatory
Appendix or referencing Code Section.
MISCELLANEOUS REQUIREMENTS
CLEANLINESS
T-1062
TEMPERATURE MEASURING DEVICES
When temperature measurement is required by the referencing Code Section or Mandatory Appendix, the device(s) shall be calibrated in accordance with the
requirements of that Code Section or Mandatory
Appendix.
OPENINGS
All openings shall be sealed using plugs, covers, sealing
wax, cement, or other suitable material that can be readily
and completely removed after completion of the test.
Sealing materials shall be tracer gas free.
T-1063
T-1043
PROCEDURE
Prior to employing a sensitive leak testing method, it
may be expedient to perform a preliminary test to detect
and eliminate gross leaks. This shall be done in a manner
that will not seal or mask leaks during the specified test.
The surface areas to be tested shall be free of oil,
grease, paint, or other contaminants that might mask a
leak. If liquids are used to clean the component or if a hydrostatic or hydropneumatic test is performed before
leak testing, the component shall be dry before leak
testing.
T-1042
PRESSURE/VACUUM (PRESSURE LIMITS)
TEMPERATURE
CALIBRATION LEAK STANDARDS
T-1063.1 Reservoir Leak Standard. This standard
leak shall have a reservoir of the tracer gas connected
to the leak. The leak standard shall
(a) have a leakage rate in the range and tracer gas species specified by the referencing Code Section or, if not
specified, per the Mandatory Appendix.
(b) be calibrated with discharge either to vacuum or to
an air environment of 1 atm (101 kPa absolute) to match
the test application or instrument type.
The minimum metal temperature for all components
during a test shall be as specified in the applicable Mandatory Appendix of this Article or in the referencing Code
Section for the hydrostatic, hydropneumatic, or pneumatic test of the pressure component or parts. The minimum or maximum temperature during the test shall not
exceed that temperature compatible with the leak testing
method or technique used.
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ASME BPVC.V-2021
T-1090
T-1063.2 Nonreservoir Leak Standard. This standard leak does not have an inherent supply of tracer
gas. The leak shall
(a) have a leakage rate in the range and tracer gas species specified by the referencing Code Section or, if not
specified, per the Mandatory Appendix.
(b) be calibrated with discharge either to vacuum or to
an air environment of 1 atm (101 kPa absolute) to match
the test application.
(c) be calibrated at a pressure differential across the
leak of 1 atm (14.7 psi, 101 kPa) or at a differential that
represents the differential to be used in the specific test
procedure.
T-1070
T-1091
T-1081
DOCUMENTATION
TEST REPORT
The test report shall contain, as a minimum, the following information as applicable to the method or technique:
(a) date of test
(b) certified level and name of operator
(c) test procedure (number) and revision number
(d) test method or technique
(e) test results
(f) component identification
(g) test instrument, standard leak, and material
identification
(h) test conditions, test pressure, tracer gas, and gas
concentration
(i) gage(s) — manufacturer, model, range, and identification number
(j) temperature measuring device(s) and identification
number(s)
(k) sketch showing method or technique setup
TEST
See applicable Mandatory Appendix of this Article.
T-1080
ARTICLE 10
EVALUATION
ACCEPTANCE STANDARDS
Unless otherwise specified in the referencing Code Section, the acceptance criteria given for each method or
technique of that method shall apply. The supplemental
leak testing equations for calculating leakage rates for
the method or technique used are stated in the Mandatory
Appendices of this Article.
T-1092
RECORD RETENTION
The test report shall be maintained in accordance with
the requirements of the referencing Code Section.
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ARTICLE 23, SE-797/SE-797M
STANDARD PRACTICE FOR MEASURING THICKNESS BY
MANUAL ULTRASONIC PULSE-ECHO CONTACT
METHOD
SE-797/SE-797M
(Identical with ASTM Specification E797/E797M-15.)
This document, in whole or in part, is mandatory only to the extent specified in the referencing
Article(s) of Subsection A, or as indicated in other Code Sections or referencing documents.
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ASME BPVC.V-2021
Standard Practice for
Measuring Thickness by Manual Ultrasonic Pulse-Echo
Contact Method
1. Scope
2.2 ASNT Documents:
Nondestructive Testing Handbook, 2nd Edition, Vol 7
SNT-TC-1A Recommended Practice for Personnel Qualification and Certification in Nondestructive Testing
ANSI/ASNT CP-189 Standard for Qualification and Certification of Nondestructive Testing Personnel
2.3 Aerospace Industries Association Document:
NAS-410 Certification and Qualification of Nondestructive
Testing Personnel
2.4 ISO Standard:
ISO 9712 Non-Destructive Testing—Qualification and Certification of NDT Personnel
1.1 This practice provides guidelines for measuring the
thickness of materials using the contact pulse-echo method at
temperatures not to exceed 93°C [200°F].
1.2 This practice is applicable to any material in which
ultrasonic waves will propagate at a constant velocity throughout the part, and from which back reflections can be obtained
and resolved.
1.3 Units—The values stated in either SI units or inchpound units are to be regarded separately as standard. The
values stated in each system may not be exact equivalents;
therefore, each system shall be used independently of the other.
Combining values from the two systems may result in nonconformance with the standard.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
3. Terminology
3.1 Definitions: Definitions—For definitions of terms used
in this practice, refer to Terminology E1316.
4. Summary of Practice
4.1 Thickness (T), when measured by the pulse-echo ultrasonic method, is a product of the velocity of sound in the
material and one half the transit time (round trip) through the
material.
2. Referenced Documents
2.1 ASTM Standards:
E317 Practice for Evaluating Performance Characteristics of
Ultrasonic Pulse-Echo Testing Instruments and Systems
without the Use of Electronic Measurement Instruments
E494 Practice for Measuring Ultrasonic Velocity in Materials
E543 Specification for Agencies Performing Nondestructive
Testing
E1316 Terminology for Nondestructive Examinations
T5
Vt
2
where:
T = thickness,
V = velocity, and
t = transit time.
4.2 The pulse-echo ultrasonic instrument measures the transit time of the ultrasonic pulse through the part.
4.3 The velocity in the material being examined is a
function of the physical properties of the material. It is usually
assumed to be a constant for a given class of materials. Its
approximate value can be obtained from Table X3.1 in Practice
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ARTICLE 23, SE-797/SE-797M
NOTE 1—Slope of velocity conversion line is approximately that of steel.
FIG. 1 Transit Time/Thickness Relationship
5. Significance and Use
E494 or from the Nondestructive Testing Handbook, or it can
be determined empirically.
5.1 The techniques described provide indirect measurement
of thickness of sections of materials not exceeding temperatures of 93°C [200°F]. Measurements are made from one side
of the object, without requiring access to the rear surface.
4.4 One or more reference blocks are required having
known velocity, or of the same material to be examined, and
having thicknesses accurately measured and in the range of
thicknesses to be measured. It is generally desirable that the
thicknesses be “round numbers” rather than miscellaneous odd
values. One block should have a thickness value near the
maximum of the range of interest and another block near the
minimum thickness.
5.2 Ultrasonic thickness measurements are used extensively
on basic shapes and products of many materials, on precision
machined parts, and to determine wall thinning in process
equipment caused by corrosion and erosion.
5.3 Recommendations for determining the capabilities and
limitations of ultrasonic thickness gages for specific applications can be found in the cited references.1,2
4.5 The display element (A-scan display, meter, or digital
display) of the instrument must be adjusted to present convenient values of thickness dependent on the range being used.
The control for this function may have different names on
different instruments, including range, sweep, material
standardize, or velocity.
6. Basis of Application
6.1 The following items are subject to contractual agreement between the parties using or referencing this practice.
6.2 Personnel Qualification:
6.2.1 If specified in the contractual agreement, personnel
performing examinations to this standard shall be qualified in
accordance with a nationally or internationally recognized
4.6 The timing circuits in different instruments use various
conversion schemes. A common method is the so-called
time/analog conversion in which the time measured by the
instrument is converted into a proportional d-c voltage which is
then applied to the readout device. Another technique uses a
very high-frequency oscillator that is modulated or gated by the
appropriate echo indications, the output being used either
directly to suitable digital readouts or converted to a voltage for
other presentation. A relationship of transit time versus thickness is shown graphically in Fig. 1.
1
Bosselaar, H., and Goosens, J.C.J., “Method to Evaluate Direct-Reading
Ultrasonic Pulse-Echo Thickness Meters,” Materials Evaluation, March 1971, pp.
45–50.
2
Fowler, K.A., Elfbaum, G.M., Husarek, V., and Castel, J., “Applications of
Precision Ultrasonic Thickness Gaging,” Proceedings of the Eighth World Conference on Nondestructive Testing, Cannes, France, Sept. 6–11, 1976, Paper 3F.5.
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tions. (See Fig. 2.) For optimum performance, it is often
necessary that the instrument and search units be matched.
NDT personnel qualification practice or standard such as
ANSI/ASNT CP-189, SNT-TC-1A, NAS-410, ISO 9712, or a
similar document and certified by the employer or certifying
agency, as applicable. The practice or standard used and its
applicable revision shall be identified in the contractual agreement between the using parties.
7.3 Standardization Blocks—The general requirements for
appropriate standardization blocks are given in 4.4, 8.1.3,
8.2.2.1, 8.3.2, and 8.4.3. Multi-step blocks that may be useful
for these standardization procedures are described in Appendix
X1 (Figs. X1.1 and X1.2).
6.3 Qualification of Nondestructive Agencies—If specified
in the contractual agreement, NDT agencies shall be qualified
and evaluated as described in Specification E543. The applicable edition of Specification E543 shall be specified in the
contractual agreement.
8. Standardization of Apparatus
8.1 Case I—Direct Contact, Single-Element Search Unit:
8.1.1 Conditions—The display start is synchronized to the
initial pulse. All display elements are linear. Full thickness is
displayed on the A-scan display.
8.1.2 Under these conditions, we can assume that the
velocity conversion line effectively pivots about the origin
(Fig. 1). It may be necessary to subtract the wear-plate time,
requiring minor use of delay control. It is recommended that
standardization blocks providing a minimum of two thicknesses that span the thickness range be used to check the
full-range accuracy.
8.1.3 Place the search unit on a standardization block of
known thickness with suitable couplant and adjust the instrument controls (material standardization, range, sweep, or
velocity) until the display presents the appropriate thickness
reading.
8.1.4 The readings should then be checked and adjusted on
standardization blocks with thickness of lesser value to improve the overall accuracy of the system.
6.4 Procedures and Techniques—The procedures and techniques to be utilized shall be as specified in the contractual
agreement.
6.5 Surface Preparation—The pre-examination surface
preparation criteria shall be specified in the contractual agreement.
7. Apparatus
7.1 Instruments—Thickness-measurement instruments are
divided into three groups: (1) Flaw detectors with an A-scan
display readout, (2) Flaw detectors with an A-scan display and
direct thickness readout, and (3) Direct thickness readout.
7.1.1 Flaw detectors with A-scan display readouts display
time/amplitude information. Thickness determinations are
made by reading the distance between the zero-corrected initial
pulse and first-returned echo (back reflection), or between
multiple-back reflection echoes, on a standardized base line of
the A-scan display. The base line of the A-scan display should
be adjusted for the desired thickness increments.
7.1.2 Flaw detectors with numeric readout are a combination pulse ultrasound flaw detection instrument with an A-scan
display and additional circuitry that provides digital thickness
information. The material thickness can be electronically
measured and presented on a digital readout. The A-scan
display provides a check on the validity of the electronic
measurement by revealing measurement variables, such as
internal discontinuities, or echo-strength variations, which
might result in inaccurate readings.
7.1.3 Thickness readout instruments are modified versions
of the pulse-echo instrument. The elapsed time between the
initial pulse and the first echo or between multiple echoes is
converted into a meter or digital readout. The instruments are
designed for measurement and direct numerical readout of
specific ranges of thickness and materials.
8.2 Case II—Delay Line Single-Element Search Unit:
8.2.1 Conditions—When using this search unit, it is necessary that the equipment be capable of correcting for the time
during which the sound passes through the delay line so that
the end of the delay can be made to coincide with zero
thickness. This requires a so-called “delay” control in the
instrument or automatic electronic sensing of zero thickness.
8.2.2 In most instruments, if the material standardize circuit
was previously adjusted for a given material velocity, the delay
control should be adjusted until a correct thickness reading is
obtained on the instrument. However, if the instrument must be
completely standardized with the delay line search unit, the
following technique is recommended:
8.2.2.1 Use at least two standardization blocks. One should
have a thickness near the maximum of the range to be
measured and the other block near the minimum thickness. For
convenience, it is desirable that the thickness should be “round
numbers” so that the difference between them also has a
convenient “round number” value.
8.2.2.2 Place the search unit sequentially on one and then
the other block, and obtain both readings. The difference
between these two readings should be calculated. If the reading
thickness difference is less than the actual thickness difference,
place the search unit on the thicker specimen, and adjust the
material standardize control to expand the thickness range. If
the reading thickness difference is greater than the actual
thickness difference, place the search unit on the thicker
specimen, and adjust the material standardize control to decrease the thickness range. A certain amount of over correction
7.2 Search Units—Most pulse-echo type search units
(straight-beam contact, delay line, and dual element) are
applicable if flaw detector instruments are used. If a thickness
readout instrument has the capability to read thin sections, a
highly damped, high-frequency search unit is generally used.
High-frequency (10 MHz or higher) delay line search units are
generally required for thicknesses less than about 0.6 mm
[0.025 in.]. Measurements of materials at high temperatures
require search units specially designed for the application.
When dual element search units are used, their inherent
nonlinearity usually requires special corrections for thin sec-
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ARTICLE 23, SE-797/SE-797M
(a) Proportional sound path increases with decrease in thickness.
(b) Typical reading error values.
FIG. 2 Dual Transducer Nonlinearity
thickness end of the range. The variation is also shown
schematically in Fig. 2(a). Typical error values are shown in
Fig. 2(b).
8.3.2 If measurements are to be made over a very limited
range near the thin end of the scale, it is possible to standardize
the instrument with the technique in Case II using appropriate
thin standardization blocks. This will produce a correction
curve that is approximately correct over that limited range.
Note that it will be substantially in error at thicker measurements.
8.3.3 If a wide range of thicknesses is to be measured, it
may be more suitable to standardize as in Case II using
standardization blocks at the high end of the range and perhaps
halfway toward the low end. Following this, empirical corrections can be established for the very thin end of the range.
8.3.4 For a direct-reading panel-type meter display, it is
convenient to build these corrections into the display as a
nonlinear function.
is usually recommended. Reposition the search unit sequentially on both blocks, and note the reading differences while
making additional appropriate corrections. When the reading
thickness differential equals the actual thickness differential,
the material thickness range is correctly adjusted. A single
adjustment of the delay control should then permit correct
readings at both the high and low end of the thickness range.
8.2.3 An alternative technique for delay line search units is
a variation of that described in 8.2.2. A series of sequential
adjustments are made, using the “delay” control to provide
correct readings on the thinner standardization block and the
“range” control to correct the readings on the thicker block.
Moderate over-correction is sometimes useful. When both
readings are “correct” the instrument is adjusted properly.
8.3 Case III—Dual Search Units:
8.3.1 The method described in 8.2 (Case II) is also suitable
for equipment using dual search units in the thicker ranges,
above 3 mm [0.125 in.]. However, below those values there is
an inherent error due to the Vee path that the sound beam
travels. The transit time is no longer linearly proportional to
thickness, and the condition deteriorates toward the low
8.4 Case IV—Thick Sections:
8.4.1 Conditions—For use when a high degree of accuracy
is required for thick sections.
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from steel walls having elevated temperatures is high (too
thick) by a factor of about 1 % per 55°C [100°F]. Thus, if the
instrument was standardized on a piece of similar material at
20°C [68°F], and if the reading was obtained with a surface
temperature of 460°C [860°F], the apparent reading should be
reduced by 8 %. This correction is an average one for many
types of steel. Other corrections would have to be determined
empirically for other materials.
8.4.2 Direct contact search unit and initial pulse synchronization are used. The display start is delayed as described in
8.4.4. All display elements should be linear. Incremental
thickness is displayed on the A-scan display.
8.4.3 Basic standardization of the sweep will be made as
described in Case I. The standardization block chosen for this
standardization should have a thickness that will permit standardizing the full-sweep distance to adequate accuracy, that is,
about 10 mm [0.4 in.] or 25 mm [1.0 in.] full scale.
8.4.4 After basic standardization, the sweep must be delayed. For instance, if the nominal part thickness is expected to
be from 50 to 60 mm [2.0 to 2.4 in.], and the basic standardization block is 10 mm [0.4 in.], and the incremental thickness
displayed will also be from 50 to 60 mm [2.0 to 2.4 in.], the
following steps are required. Adjust the delay control so that
the fifth back echo of the basic standardization block, equivalent to 50 mm [2.0 in.], is aligned with the 0 reference on the
A-scan display. The sixth back echo should then occur at the
right edge of the standardized sweep.
8.4.5 This standardization can be checked on a known block
of the approximate total thickness.
8.4.6 The reading obtained on the unknown specimen must
be added to the value delayed off screen. For example, if the
reading is 4 mm [0.16 in.], the total thickness will be 54 mm
[2.16 in.].
9.6 Instrument—Time-base linearity is required so that a
change in the thickness of material will produce a corresponding change of indicated thickness. If a CRT is used as a
readout, its horizontal linearity can be checked by using
Practice E317.
9.7 Back Reflection Wavetrain—Direct-thickness readout
instruments read the thickness at the first half cycle of the
wavetrain that exceeds a set amplitude and a fixed time. If the
amplitude of the back reflection from the measured material is
different from the amplitude of the back reflection from the
standardization blocks, the thickness readout may read to a
different half cycle in the wavetrain, thereby producing an
error. This may be reduced by:
9.7.1 Using reference blocks having attenuation characteristics equal to those in the measured material or adjusting back
reflection amplitude to be equal for both the standardizing
blocks and measured material.
9.7.2 Using an instrument with automatic gain control to
produce a constant amplitude back reflection.
9. Technical Hazards
9.1 Dual search units may also be used effectively with
rough surface conditions. In this case, only the first returned
echo, such as from the bottom of a pit, is used in the
measurement. Generally, a localized scanning search is made
to detect the minimum remaining wall.
9.8 Readouts—A-scan displays are recommended where
reflecting surfaces are rough, pitted, or corroded.
9.8.1 Direct-thickness readout, without an A-scan display,
presents hazards of misadjustment and misreading under certain test conditions, especially thin sections, rough corroded
surfaces, and rapidly changing thickness ranges.
9.2 Material Properties—The instrument should be standardized on a material having the same acoustic velocity and
attenuation as the material to be measured. Where possible,
standardization should be confirmed by direct dimensional
measurement of the material to be examined.
9.9 Reference Standards—Greater accuracy can be obtained
when the equipment is standardized on areas of known
thickness of the material to be measured.
9.3 Scanning—The maximum speed of scanning should be
stated in the procedure. Material conditions, type of equipment,
and operator capabilities may require slower scanning.
9.10 Variations in echo signal strength may produce an error
equivalent to one or more half-cycles of the RF frequency,
dependent on instrumentation characteristics.
9.4 Geometry:
9.4.1 Highest accuracy can be obtained from materials with
parallel or concentric surfaces. In many cases, it is possible to
obtain measurements from materials with nonparallel surfaces.
However, the accuracy of the reading may be limited and the
reading obtained is generally that of the thinnest portion of the
section being interrogated by the sound beam at a given instant.
9.4.2 Relatively small-diameter curves often require special
techniques and equipment. When small diameters are to be
measured, special procedures including additional specimens
may be required to ensure accuracy of setup and readout.
10. Procedure Requirements
10.1 In developing the detailed procedure, the following
items should be considered:
10.1.1 Instrument manufacturer’s operating instructions
10.1.2 Scope of materials/objects to be measured
10.1.3 Applicability, accuracy requirements
10.1.4 Definitions
10.1.5 Requirements
10.1.5.1 Personnel
10.1.5.2 Equipment
10.1.5.3 Procedure qualification
10.1.5.4 Training or certification levels
10.1.6 Procedure
10.1.6.1 Measurement conditions
10.1.6.2 Surface preparation and couplant
10.1.6.3 Standardization and allowable tolerances
10.1.6.4 Scanning parameters
9.5 High-temperature materials, up to about 540°C
[1000°F], can be measured with specially designed instruments
with high-temperature compensation, search unit assemblies,
and couplants. Normalization of apparent thickness readings
for elevated temperatures is required. A rule of thumb often
used is as follows: The apparent thickness reading obtained
658
ASME BPVC.V-2021
10.1.7 Report
10.1.7.1 Procedure used
10.1.7.2 Standardization record
10.1.7.3 Measurement record
ARTICLE 23, SE-797/SE-797M
11.1.1.3 Size, frequency, and type of search unit.
11.1.1.4 Scanning method.
11.1.2 Results.
11.1.2.1 Maximum and minimum thickness measurements.
11.1.2.2 Location of measurements.
11.1.3 Personnel data, certification level.
11. Report
11.1 Record the following information at the time of the
measurements and include it in the report:
11.1.1 Examination procedure.
11.1.1.1 Type of instrument.
11.1.1.2 Standardization blocks, size and material type.
12. Keywords
12.1 contact examination; nondestructive testing; pulseecho; thickness measurement; ultrasonics
APPENDIX
(Nonmandatory Information)
X1. Typical Multi-Step Thickness Gage Reference Blocks
TABLE OF DIMENSIONS
Metric Block 4A, mm
U.S. Customary Block, in.
Metric Block 4B, mm
Legend
Dimension
Tolerance
Dimension
Tolerance
Dimension
Tolerance
T1
T2
T3
T4
L
W
0.250
0.500
0.750
1.000
0.75
0.75
0.001
0.001
0.001
0.001
0.02
0.05
6.25
12.50
18.75
25.00
20.0
20.0
0.02
0.02
0.02
0.02
0.5
1.0
5.00
10.00
15.00
20.00
20.0
20.0
0.02
0.02
0.02
0.02
0.5
1.0
NOTE 1—Material to be as specified.
NOTE 2—Surface finish: “T” faces Ra 0.8 µm [32 µin.] max. Other surfaces Ra 1.6 µm [63 µin.] max.
NOTE 3—Location for optional 1.5 mm [1⁄16 in.] diameter through hole used for block support during plating; center 1.5 mm [1⁄16 in.] from block edges.
NOTE 4—All “T” dimensions to be after any required plating or anodizing.
NOTE 5—In order to prevent sharp edges, minimize plating buildup, or remove in-service nicks and burrs, block edges may be smoothed by beveling
or rounding, provided that the corner treatment does not reduce the edge dimension by more than 0.5 mm [0.020 in.].
FIG. X1.1 Typical Four-Step Thickness Reference Blocks
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TABLE OF DIMENSIONS
Metric Block 5A, mm
U.S. Customary Block, in.
Metric Block 5B, mm
Legend
Dimension
Tolerance
Dimension
Tolerance
Dimension
Tolerance
T1
T2
T3
T4
T5
L
W
0.100
0.200
0.300
0.400
0.500
0.75
0.75
0.001
0.001
0.001
0.001
0.001
0.02
0.05
2.50
5.00
7.50
10.00
12.50
20.0
20.0
0.02
0.02
0.02
0.02
0.02
0.5
1.0
2.00
4.00
6.00
8.00
10.00
20.00
20.00
0.02
0.02
0.02
0.02
0.02
0.5
1.0
NOTE 1—Material to be as specified.
NOTE 2—Surface finish: “T” faces Ra 0.8 µm [32 µin.] max. Other surfaces Ra 1.6 µm [63 µin.] max.
NOTE 3—Location for optional 1.5 mm [1⁄16 in.] diameter through hole used for block support during plating; center 1.5 mm [1⁄16 in.] from block edges.
NOTE 4—All “T” dimensions to be after any required plating or anodizing.
NOTE 5—In order to prevent sharp edges, minimize plating buildup, or remove in-service nicks and burrs, block edges may be smoothed by beveling
or rounding, provided that the corner treatment does not reduce the edge dimension by more than 0.5 mm [0.020 in.].
FIG. X1.2 Typical Five-Step Thickness Reference Blocks
660