ASTM E1118-95
(Practice)Standard Practice for Acoustic Emission Examination of Reinforced Thermosetting Resin Pipe (RTRP)
Standard Practice for Acoustic Emission Examination of Reinforced Thermosetting Resin Pipe (RTRP)
SCOPE
1.1 This practice covers acoustic emission (AE) examination or monitoring of reinforced thermosetting resin pipe (RTRP) to determine structural integrity. It is applicable to lined or unlined pipe, fittings, joints, and piping systems.
1.2 This practice is applicable to pipe that is fabricated with fiberglass and carbon fiber reinforcements with reinforcing contents greater than 15 % by weight. The suitability of these procedures must be demonstrated before they are used for piping that is constructed with other reinforcing materials.
1.3 This practice is applicable to tests below pressures of 35 MPa absolute (5000 psia).
1.4 This practice is limited to pipe up to and including 0.6 m (24 in.) in diameter. Larger diameter pipe can be examined with AE, however, the procedure is outside the scope of this practice.
1.5 This practice applies to examinations of new or in-service RTRP.
1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.7 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 to determine the applicability of regulatory limitations prior to use. For more specific safety precautionary information see 8.1.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: E 1118 – 95 An American National Standard
Standard Practice for
Acoustic Emission Examination of Reinforced
Thermosetting Resin Pipe (RTRP)
This standard is issued under the fixed designation E 1118; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope E 1316 Terminology for Nondestructive Examinations
1.1 This practice covers acoustic emission (AE) examina-
3. Terminology
tion or monitoring of reinforced thermosetting resin pipe
3.1 Complete glossaries of terms related to plastics and
(RTRP) to determine structural integrity. It is applicable to
acoustic emission will be found in Terminologies D 883 and
lined or unlined pipe, fittings, joints, and piping systems.
E 1316.
1.2 This practice is applicable to pipe that is fabricated with
3.2 Definitions of Terms Specific to This Standard:
fiberglass and carbon fiber reinforcements with reinforcing
3.2.1 component and assembly proof testing—a program of
contents greater than 15 % by weight. The suitability of these
tests on RTRP components designed to assess product quality
procedures must be demonstrated before they are used for
in a manufacturer’s plant, at the installation site, or when taken
piping that is constructed with other reinforcing materials.
out of service for retesting. An assembly is a shippable unit of
1.3 This practice is applicable to tests below pressures of 35
factory-assembled components.
MPa absolute (5000 psia).
3.2.2 count value N —an evaluation criterion based on the
c
1.4 This practice is limited to pipe up to and including 0.6
total number of AE counts. (See A2.5.)
m (24 in.) in diameter. Larger diameter pipe can be examined
D 1 D
o i
with AE, however, the procedure is outside the scope of this
3.2.3 diameter to thickness ratio (d/t)—equal to
2t
practice.
where (D ) is the outside pipe diameter, (D ) is the inside pipe
o i
1.5 This practice applies to examinations of new or in-
diameter, and (t) is the wall thickness, as measured in a section
service RTRP.
of straight pipe.
1.6 The values stated in SI units are to be regarded as the
3.2.4 high-amplitude threshold—a threshold for large am-
standard. The values given in parentheses are for information
plitude events. (See A2.3.)
only.
3.2.5 in-service systems testing—a program of periodic tests
1.7 This standard does not purport to address all of the
during the lifetime of an RTRP system designed to assess its
safety concerns, if any, associated with its use. It is the
structural integrity.
responsibility of the user of this standard to establish appro-
3.2.6 low-amplitude threshold—the threshold above which
priate safety and health practices and to determine the
AE counts (N) are measured. (See A2.2.)
applicability of regulatory limitations prior to use. For more
3.2.7 manufacturers qualification testing—a comprehensive
specific safety precautionary information see 8.1.
program of tests to confirm product design, performance
acceptability, and fabricator capability.
2. Referenced Documents
3.2.8 operating pressure—pressure at which the RTRP nor-
2.1 ASTM Standards:
mally operates. It should not exceed design pressure.
D 883 Terminology Relating to Plastics
3.2.9 qualification test pressure—a test pressure which is set
E 650 Guide for Mounting Piezoelectric Acoustic Emission
by agreement between the user, manufacturer, or test agency, or
Sensors
combination thereof.
E 750 Practice for Measuring Operating Characteristics of
3.2.10 rated pressure—a nonstandard term used by RTRP
Acoustic Emission Instrumentation
pipe manufacturers as an indication of the maximum operating
E 976 Guide for Determining the Reproducibility of Acous-
pressure.
tic Emission Sensor Response
3.2.11 RTRP—Reinforced Thermosetting Resin Pipe, a tu-
bular product containing reinforcement embedded in or sur-
This practice is under the jurisdiction of ASTM Committee E-7 on Nonde-
rounded by cured thermosetting resin.
structive Testing and is the direct responsibility of Subcommittee E07.04 on
3.2.12 RTRP system—a pipe structure assembled from vari-
Acoustic Emission.
Current edition approved Jan. 15, 1995. Published March 1995. Originally ous components that are bonded, threaded, layed-up, etc., into
published as E 1118 – 86. Last previous edition E 1118 – 89.
a functional unit.
Annual Book of ASTM Standards, Vol 08.01.
3.2.13 signal value M—a measure of the AE signal power
Annual Book of ASTM Standards, Vol 03.03.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 1118
(energy/unit time) which is used to indicate adhesive bond on AE instrumentation can be found in Practice E 750.
failure in RTRP cemented joints. (See A2.4.) 7.2 Instrumentation shall be capable of recording AE counts
3.2.14 summing amplifier (summer, mixer)—an operational and AE events above the low-amplitude threshold. It shall also
amplifier that produces an output signal equal to a weighted record events above the high-amplitude threshold as well as
sum of the input signals. signal value M within specific frequency ranges, and have
3.2.15 system proof testing—a program of tests on an sufficient channels to localize AE sources in real time. It may
assembled RTRP system designed to assess its structural incorporate (as an option) peak amplitude detection. An AE
integrity prior to in-service use. event amplitude measurement is recommended for sensitivity
verification (see Annex A2). Amplitude distributions are rec-
4. Summary of Practice
ommended for flaw characterization. It is preferred that the AE
4.1 This practice consists of subjecting RTRP to increasing
instrumentation acquire and record count, event, amplitude,
or cyclic pressure while monitoring with sensors that are
and signal value M information on a per channel basis. The AE
sensitive to acoustic emission (transient stress waves) caused
instrumentation is further described in Annex A1.
by growing flaws. Where appropriate, other types of loading
7.3 Capability for measuring parameters such as time and
may be superposed or may replace the pressure load, for
pressure shall be provided. The pressure-load shall be continu-
example, thermal, bending, tensile, etc. The instrumentation
ously monitored to an accuracy of 62 % of the maximum test
and techniques for sensing and analyzing AE data are de-
value.
scribed.
8. Test Preparations
4.2 This practice provides guidelines to determine the loca-
tion and severity of structural flaws in RTRP.
8.1 Safety Precautions—All plant safety requirements
4.3 This practice provides guidelines for AE examination of
unique to the test location shall be met.
RTRP within the pressure range stated in 1.2. Maximum test
8.1.1 Protective clothing and equipment that is normally
pressure for RTRP will be determined upon agreement among
required in the area in which the test is being conducted shall
user, manufacturer, or test agency, or combination thereof. The
be worn.
test pressure will normally be 1.1 multiplied by the maximum
8.1.2 A fire permit may be needed to use the electronic
operating pressure.
instrumentation.
8.1.3 Precautions shall be taken against the consequences of
5. Significance and Use
catastrophic failure when testing, for example, flying debris
5.1 The AE examination method detects damage in RTRP.
and impact of escaping liquid.
The damage mechanisms detected in RTRP are as follows:
8.1.4 Pneumatic testing is extremely dangerous and shall be
resin cracking, fiber debonding, fiber pullout, fiber breakage,
avoided if at all possible.
delamination, and bond or thread failure in assembled joints.
8.2 RTRP Conditioning:
Flaws in unstressed areas and flaws which are structurally
8.2.1 If the pipe has not been previously loaded, no condi-
insignificant will not generate AE.
tioning is required.
5.2 This practice is convenient for on-line use under oper-
8.2.2 If the pipe has been previously loaded, one of two
ating conditions to determine structural integrity of in-service
methods shall be used. For both methods, the maximum
RTRP usually with minimal process disruption.
operating pressure-load in the pipe since the previous exami-
5.3 Flaws located with AE should be examined by other
nation must be known. If more than one year has elapsed since
techniques; for example, visual, ultrasound, and dye penetrant,
the last examination, the maximum operating pressure-load
and may be repaired and retested as appropriate. Repair
during the past year can be used. (See 11.2.3.)
procedure recommendations are outside the scope of this
8.2.2.1 Option I requires that the test shall be run from 90 up
practice.
to 110 % of the maximum operating pressure-load. In this case
6. Personnel Qualification no conditioning is required. (See Fig. 7.) If it is not possible to
achieve over 100 % of the maximum operating pressure-load,
6.1 The acoustic emission examination shall be performed
Option II may be used.
by qualified personnel. Qualification shall be based on a
8.2.2.2 Option II requires that the operating pressure-load
documented program that certifies personnel capable of con-
be reduced prior to testing in accordance with the schedule
ducting acoustic emission examinations of RTRP. The docu-
shown in Table 1. In this case, the maximum pressure-load
mented program shall include the following general topics:
need be only 100 % of the operating pressure (see Fig. 8).
6.1.1 Basic technology of acoustic emission.
8.3 RTRP Pressurizing-Loading—Arrangements should be
6.1.2 Failure mechanisms of reinforced plastics.
made to pressurize the RTRP to the appropriate pressure-load.
6.1.3 Acoustic emission instrumentation.
Liquid is the preferred pressurizing medium. Holding pressure-
6.1.4 Instrumentation check out.
load levels is a key aspect of an acoustic emission examination.
6.1.5 Loading requirements.
Accordingly, provision shall be made for holding the pressure-
6.1.6 Data collection and interpretation.
load at designated check points.
6.1.7 Examination report.
8.4 RTRP Support—The RTRP system shall be properly
7. Instrumentation
supported.
7.1 The AE instrumentation consists of sensors, signal 8.5 Environmental—The normal minimum acceptable
processors, and recording equipment. Additional information RTRP wall temperature is 4°C (40°F).
E 1118
NOTE 1—A maximum of three sensors can be connected into one channel.
FIG. 1 Typical Sensor Positioning for Zone Location
NOTE 1—Diameter to thickness ratio (d/t) $ 16, T 5 2 min. Diameter to thickness ratio (d/t) < 16, T 5 4 min.
H H
FIG. 2 RTRP Manufacturer’s Qualification Test, Pressurizing Sequence
8.6 Noise Reduction—Noise sources in the examination or suitable adhesive systems may be considered. Suitable
frequency and amplitude range, such as malfunctioning pumps adhesive systems are those whose bonding and acoustic
or valves, movement of pipe on supports, or rain, must be coupling effectiveness have been demonstrated. The attach-
minimized since they mask the AE signals emanating from the ment method should provide support for the signal cable (and
pipe. preamplifier) to prevent the cable(s) from stressing the sensor
8.7 Power Supply—A stable grounded power supply, meet- or causing loss of coupling.
ing the specification of the instrumentation, is required at the
9.2 Surface Contact—Reliable coupling between the sensor
test site. and pipe surface shall be ensured and the surface of the pipe in
8.8 Instrumentation Settings—Settings will be determined
contact with the sensor shall be clean and free of particulate
in accordance with Annex A2. matter. Sensors should be mounted directly on the RTRP
surface unless integral waveguides shown by test to be
9. Sensors
satisfactory are used. Preparation of the contact surface shall be
compatible with both sensor and structure modification re-
9.1 Sensor Mounting—Refer to Guide E 650 for additional
information on sensor mounting. Location and spacing of the quirements. Possible causes of signal loss are coatings such as
paint and encapsulants, inadequate sensor contact on curved
sensors are discussed in 9.4. Sensors shall be placed in the
designated locations with a couplant interface between sensor surfaces, off-center sensor positioning and surface roughness at
the contact area.
and test article. One recommended couplant is silicone-
stopcock grease. Care must be exercised to ensure that ad- 9.3 Zone Location—Several high-frequency sensors (100 to
equate couplant is applied. Sensors shall be held in place 250 kHz) are used for zone location of emission sources.
utilizing methods of attachment which do not create extraneous Attenuation is greater at higher frequencies requiring closer
signals. Methods of attachment using strips of pressure- spacing of sensors. Zones may be refined if events hit more
sensitive tape, stretch fabric tape with hook and loop fastener, than one sensor. (See Fig. 1 and Annex A3.)
E 1118
FIG. 3 AE Test Algorithm—Flow Chart, RTRP Qualification Test (see Fig. 2)
NOTE 1—Diameter to thickness ratio (d/t) $ 16, T 5 2 min. Diameter to thickness ratio (d/t) < 16, T 5 4 min.
H H
FIG. 4 RTRP Component and Assembly Proof Test, Pressurizing Sequence
9.4 Locations and Spacings—Sensor locations on the RTRP attenuation, but may not be representative of a genuine event.
are determined by the need to detect structural flaws at critical It should be noted that the peak amplitude from a mechanical
sections, for example, joints, high-stress areas, geometric pencil lead break may vary with surface hardness, resin
discontinuities, repaired regions, and visible defects. The condition, cure, and test fluid. For pressure tests, the attenua-
number of sensors and their location is based on whether full tion characterization shall be carried out with the pipe full of
coverage or random sampling of the system is desired. For full the test fluid.
coverage of the RTRP, excluding joints, sensor spacings of 3 m 9.4.1.1 Select a representative region of the RTRP. Mount
(10 ft) are usually suitable. an AE sensor and locate points at distances of 150 mm (6 in.)
9.4.1 Attenuation Characterization—Signal propagation and 300 mm (12 in.) from the center of the sensor along a line
losses shall be determined in accordance with the following parallel to the axis of the pipe. Select two additional points on
procedure. This procedure provides a relative measure of the the surface of the pipe at 150 mm (6 in.) and 300 mm (12 in.)
E
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