ASTM E2863-11
(Practice)Standard Practice for Acoustic Emission Examination of Welded Steel Sphere Pressure Vessels Using Thermal Pressurization
Standard Practice for Acoustic Emission Examination of Welded Steel Sphere Pressure Vessels Using Thermal Pressurization
SIGNIFICANCE AND USE
Because of safety considerations, regulatory agencies (for example, U.S. Department of Transportation) require periodic tests of pressurized vessels used in commercial aviation. (see Section 49, Code of Federal Regulations). AE esting has become accepted as an alternative to the common hydrostatic proof test.
An AE test should not be conducted for a period of one year after a common hydrostatic test. See Note 1.
Note 1—The Kaiser effect relates to the irreversibility of acoustic emission which results in decreased emission during a second pressurization. Common hydrostatic tests use a relatively high test pressure (200 % of normal service pressure). (See Section 49, Code of Federal Regulations.) If an AE test is performed too soon after such a hydrostatic pressurization, the AE results will be insensitive below the previous maximum test pressure.
Acoustic Emission is produced when an increasing stress level in a material causes crack growth in the material or stress related effects in a corroded surface (for example, crack growth in or between metal crystallites or spalling and cracking of oxides and other corrosion products).
While background noise may distort AE data or render it useless, heating the vessels inside an industrial oven is an almost noise free method of pressurization. Further, source location algorithms using over-determined data sets will often allow valid tests in the presence of otherwise interfering noise sources. Background noise should be reduced or controlled but the sudden occurrence of such noise does not necessarily invalidate a test.
SCOPE
1.1 This practice is commonly used for periodic inspection and testing of welded steel gaseous spheres (bottles) is the acoustic emission (AE) method. AE is used in place of hydrostatic volumetric expansion testing. The periodic inspection and testing of bottles by AE testing is achieved without depressurization or contamination as is required for hydrostatic volumetric expansion testing.
1.2 The required test pressurization is achieved by heating the bottle in an industrial oven designed for this purpose. The maximum temperature needed to achieve the AE test pressure is ≤250°F (121°C).
1.3 AE monitoring of the bottle is performed with multiple sensors during the thermal pressurization.
1.4 This practice was developed for periodic inspection and testing of pressure vessels containing Halon (UN 1044), which is commonly used aboard commercial aircraft for fire suppression. In commercial aircraft, these bottles are hermetically sealed by welding in the fill port. Exit ports are opened by explosively activated burst disks. The usage of these pressure vessels in transportation is regulated under US Department of Transportation (DOT), Code of Federal Regulations CFR 49. A DOT special permit authorizes the use of AE testing for periodic inspection and testing in place of volumetric expansion and visual inspection. These bottles are spherical with diameters ranging from 5 to 16 in. (127 to 406 mm).
1.5 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.6 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. Specific precautionary statements are given in Section 8.
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Standards Content (Sample)
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Designation:E2863–11
Standard Practice for
Acoustic Emission Examination of Welded Steel Sphere
Pressure Vessels Using Thermal Pressurization
This standard is issued under the fixed designation E2863; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This practice is commonly used for periodic inspection 2.1 ASTM Standards:
and testing of welded steel gaseous spheres (bottles) is the E543 Specification for Agencies Performing Nondestruc-
acoustic emission (AE) method. AE is used in place of tive Testing
hydrostatic volumetric expansion testing. The periodic inspec- E650 Guide for Mounting Piezoelectric Acoustic Emission
tion and testing of bottles by AE testing is achieved without Sensors
depressurizationorcontaminationasisrequiredforhydrostatic E976 Guide for Determining the Reproducibility ofAcous-
volumetric expansion testing. tic Emission Sensor Response
1.2 The required test pressurization is achieved by heating E1316 Terminology for Nondestructive Examinations
the bottle in an industrial oven designed for this purpose. The E2075 Practice for Verifying the Consistency ofAE-Sensor
maximum temperature needed to achieve the AE test pressure Response Using an Acrylic Rod
is#250°F (121°C). E2374 Guide for Acoustic Emission System Performance
1.3 AE monitoring of the bottle is performed with multiple Verification
sensors during the thermal pressurization. 2.2 ASNT Standards:
1.4 This practice was developed for periodic inspection and SNT-TC-1A Recommended Practice for Nondestructive
testing of pressure vessels containing Halon (UN 1044), which Testing Personnel Qualification and Certification
is commonly used aboard commercial aircraft for fire suppres- ANSI/ASNT CP-189 Standard for Qualification and Certi-
sion. In commercial aircraft, these bottles are hermetically fication of Nondestructive Testing Personnel
sealed by welding in the fill port. Exit ports are opened by 2.3 Code of Federal Regulations:
explosively activated burst disks. The usage of these pressure Section 49 Code of Federal Regulations, Hazardous Mate-
vessels in transportation is regulated under US Department of rials Regulations of the Department of Transportation,
Transportation(DOT),CodeofFederalRegulationsCFR 49.A Paragraphs 173.34, 173.301, 178.36, 178.37, and 178.45
DOT special permit authorizes the use of AE testing for 2.4 Compressed Gas Association Standard:
periodic inspection and testing in place of volumetric expan- Pamphlet C-5 Service Life, Seamless High Pressure Cylin-
sion and visual inspection. These bottles are spherical with ders
diameters ranging from 5 to 16 in. (127 to 406 mm).
3. Terminology
1.5 The values stated in inch-pound units are to be regarded
3.1 Definitions—See Terminology E1316 for general termi-
asthestandard.Thevaluesgiveninparenthesesaremathemati-
cal conversions to SI units that are provided for information nology applicable to this test method.
3.2 Definitions of Terms Specific to This Standard:
only and are not considered standard.
1.6 This standard does not purport to address all of the 3.2.1 marked service pressure—pressure for which a vessel
is rated. Normally, this value is stamped on the vessel
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
bility of regulatory limitations prior to use. Specific precau-
Standards volume information, refer to the standard’s Document Summary page on
tionary statements are given in Section 8.
the ASTM website.
AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
1 4
This practice is under the jurisdiction of ASTM Committee E07 on Nonde- AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments,
structive Testing and is the direct responsibility of Subcommittee E07.04 on 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
Acoustic Emission Method. www.access.gpo.gov.
Current edition approved Dec. 15, 2011. Published January 2012. DOI:10.1520/ Available from Compressed Gas Association (CGA), 4221 Walney Rd., 5th
E2863-11. Floor, Chantilly, VA 20151-2923, http://www.cganet.com.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E2863–11
4. Summary of Practice 6. Basis of Application
4.1 Acoustic emission (AE) sensors are mounted on a 6.1 The following items are subject to contractual agree-
pressure vessel, and emission is monitored while the pressure ment between the parties using or referencing this standard.
vessel is heated to a pre-determined temperature for achieving 6.2 Personnel Qualification:
the desired AE test pressure. The elevated temperature results
6.2.1 If specified in the contractual agreement, personnel
inexpansionofthegaseouscomponentandcausestheincrease performing examinations to this standard shall be qualified in
of the internal pressure. This increasing pressure applies stress
accordance with a nationally or internationally recognized
in the pressure vessel wall. The ultimate pressure is calculated NDT personnel qualification practice or standard such as
based on the contents of the pressure vessel (bottle) and
ANSI/ASNT-CP-189, SNT-TC-1A, NAS-410, or a similar
maximum operating temperature that bottle has been exposed documentedandcertifiedbytheemployerorcertifyingagency,
(for example, during fast filling).
as applicable. The practice or standard used and its applicable
4.2 Sensors are mounted in at least six positions on the
revision shall be identified in the contractual agreement be-
vessel and are connected to an acoustic emission signal
tween the using parties.
processor. The signal processor uses measured times of arrival
6.2.2 The NDT personnel shall be qualified in accordance
of emission bursts to determine the location of emission
with a nationally recognized NDT personnel qualification
sources on the vessels surface. The locations are continually
practice or standard such as ANSI/ASNT CP-189, SNT-TC-
checked for clustering. If a cluster grows large enough (refer to
1A, or a similar document. The practice or standard used and
Appendix X1), and/or its behavior with increasing temperature
its applicable revision shall be specified in the contractual
(pressure) departs significantly from a linear increase (refer to
agreement between the using parties.
Appendix X1), the vessel is declared unsatisfactory for con-
6.3 Qualification of Nondestructive Testing Agencies—If
tinued service.
specified in the contractual agreement, NDT agencies shall be
4.3 Bottles that fail this AE examination procedure cannot
qualifiedandevaluatedasdescribedinSpecificationE543.The
be subjected to a secondary examination (for example, hydro-
applicable edition of Specification E543 shall be specified in
static volumetric expansion test) because the AE test is the
the contractual agreement.
more sensitive test. When a bottle has been rejected by an AE
6.4 Procedures and Techniques—The procedures and tech-
test, it should be rendered unserviceable.
niques to be utilized shall be as specified in the contractual
4.4 To repeat a valid AE examination on a bottle, a
agreement.
minimum of six months interval shall be required to the bottle
6.5 Surface Preparation—The pre-examination surface
after its highest previous internal pressure.
reparation criteria shall be in accordance with 10.2.1, unless
otherwise specified.
5. Significance and Use
6.6 Reporting Criteria/Acceptance Criteria—Reporting cri-
5.1 Because of safety considerations, regulatory agencies
teria for the examination results shall be in accordance with
(for example, U.S. Department of Transportation) require
Appendix X1 unless otherwise specified.
periodic tests of pressurized vessels used in commercial
aviation. (see Section 49, Code of Federal Regulations). AE
7. Apparatus
esting has become accepted as an alternative to the common
7.1 Essential features of the apparatus required for this
hydrostatic proof test.
practice are provided in Fig. 1. Full specifications are inAnnex
5.2 AnAE test should not be conducted for a period of one
A1.
year after a common hydrostatic test. See Note 1.
7.2 A couplant can be used between the sensors and vessel
NOTE 1—The Kaiser effect relates to the irreversibility of acoustic
wall. The small diameter of the sensor and significant contact
emission which results in decreased emission during a second pressuriza-
pressure reduces the requirement for a couplant, but it is often
tion. Common hydrostatic tests use a relatively high test pressure (200 %
useful when positioning a vessel in the test frame to avoid
of normal service pressure). (See Section 49, Code of Federal Regula-
interfering features on its surface or when the first AST
tions.) If an AE test is performed too soon after such a hydrostatic
coupling test has failed.
pressurization, the AE results will be insensitive below the previous
maximum test pressure.
7.3 AE Sensors are held in place by means of spring-loaded
rods mounted to the test frame.
5.3 Acoustic Emission is produced when an increasing
7.4 The AE sensors are continuously monitored throughout
stress level in a material causes crack growth in the material or
stress related effects in a corroded surface (for example, crack the pressurization.
7.5 A preamplifier for each sensor is located outside the
growthinorbetweenmetalcrystallitesorspallingandcracking
of oxides and other corrosion products). oven. The sensor cable length must not exceed 6 ft (2 m).
5.4 While background noise may distort AE data or render 7.6 The signal processor is a computerized instrument with
it useless, heating the vessels inside an industrial oven is an independent channels that filter, measure, and convert analog
almost noise free method of pressurization. Further, source information into digital form for analysis, display and perma-
location algorithms using over-determined data sets will often nent storage.Asignal processor must have sufficient speed and
allow valid tests in the presence of otherwise interfering noise capacity to independently process data from all sensors simul-
sources. Background noise should be reduced or controlled but taneously. The signal processor must be programed to locate
the sudden occurrence of such noise does not necessarily thesourcesonthesurfacesofthevesselandtodetectclustering
invalidate a test. of the sources. The instrument must be capable of reading the
E2863–11
FIG. 1 AE System Block Diagram
8. Safety Precautions
8.1 This examination involves pressurization of sealed ves-
sels by heating. When a significant defect is detected, there is
nomethodofdecreasingtheinternalpressureexceptcoolingof
the vessel. It is imperative that the heating cease as soon as a
significantdefectisidentified.ThisrequiresthattheAEsystem
have complete control over the examination, including the pre
and post-examination system performance verification; the
oven heaters; detecting, identifying and classifying defects and
the determination of when the defect behavior requires the test
to be stopped, decreasing the possibility of an explosion. The
operator has no control over the carrying out of the test,
including analysis and grading of defects or when to stop the
test for safety reasons.
8.2 Maximum temperature of the oven’s heating element
surface must remain below 800°F (427°C). This will prevent
thermal decomposition of the HALON 1301 into toxic byprod-
ucts in the event of an accidental release.
8.3 HALON1301,itself,haslowtoxicitybutarapidrelease
of pressure could rupture the oven and/or present an asphyxi-
FIG. 2 AE Sensor Holding Fixture (sensors on the head of the
ation hazard in a small enclosed region.
spring loaded rods)
9. Calibration and Verification
vessel temperature and controlling the industrial oven. It must
9.1 Annual calibration and verification of AE sensors,
also conduct and interpret AST tests both before and after the
thermal pressurization. preamplifiers, signal processor (particularly the signal proces-
sor time reference), and AE electronic waveform generator,
7.6.1 Hard copy capability should be available from a
printer or equivalent device. should be performed. Equipment should be adjusted so that it
E2863–11
FIG. 3 Picture of Halon Bottle Test System Showing Oven, AE System, Halon Bottle on Oven Shelf.
conforms to equipment manufacturer’s specifications. Instru- under the control of the AE system. The steps which must be
ments used for calibrations must have current accuracy certi- conducted by the operator and the function of the automated
fication that is traceable to the National Institute for Standards AE system follow:
and Technology (NIST). 10.2 Pre-Examination Operator Procedure:
9.2 Routine electronic evaluations must be performed 10.2.1 Visually examine the exterior surfaces of the vessel.
within 30 days prior to a test or any time there is concern about Note observations in test report.
signal processor performance. An AE electronic waveform
10.2.2 Note pertinent information from the vessel manufac-
generator should be used in making evaluations. Each signal turers stamping (SN, etc) and record in report.
processor channel must respond with peak amplitude reading
10.2.3 Adjust frame for correct bottle size if necessary.
within 62 dB of the electronic waveform generator output.
10.2.4 Installvesselintotheframeandcouplethesensorsto
9.3 Routine sensor performance verification must be per-
the vessel.
formed within 30 days prior to the test date and any time there
10.2.5 Attach thermocouple to the lower wall of the vessel.
is concern for sensor performance. A procedure for sensor
10.2.6 Slide the frame and vessel into the oven.
performance verification is found in Practice E2075.
10.2.7 Start AE system.
9.4 Asystem performance check must be conducted as part
10.2.8 Operator must stay in the immediate vicinity during
of the AE test immediately before and after thermal pressur-
the examination in case the system halts the examination
ization. A performance check uses a feature of the AE system
becauseofpendingvesselfailure.Ifthealarmsounds,clearthe
known as “Auto Sensor Test (AST).” When initiated,
...
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