1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS 9690-2:2011Non-destructive testing Guided wave testingPart 2: Basic requirements forguided wave testing of pipes,pipelines and structural tubularsPublishing and copyright info
2、rmationThe BSI copyright notice displayed in this document indicates when the documentwas last issued. BSI 2011ISBN 978 0 580 73794 7ICS 19.100The following BSI references relate to the work on this standard:Committee reference WEE/46Draft for comment 11/30238603 DCPublication historyFirst published
3、 October 2011Amendments issued since publicationDate Text affectedBS 9690-2:2011 BRITISH STANDARDContentsForeword ii1 Scope 12 Normative references 13 Terms and definitions 24 Factors influencing the performance of guided wave testing of pipes 25 Information and requirements to be agreed and documen
4、ted 36 Test procedure 47 Personnel qualification 58 Equipment calibration 59 Testing 510 Initial interpretation of results 811 Test report contents 14AnnexesAnnex A (informative) Background to the GWT method 15Bibliography 16List of figuresFigure 1 Example guided wave data (linear amplitude scale A-
5、scan) showingthe relationship between the DAC curves, noise line and maximum usablesensitivity line 12Summary of pagesThis document comprises a front cover, an inside front cover, pages i to ii,pages 1 to 16, an inside back cover and a back cover.BRITISH STANDARD BS 9690-2:2011 BSI 2011 iForewordPub
6、lishing informationThis part of BS 9690 is published by BSI and came into effect on31 October 2011. It was prepared by Technical Committee WEE/46,Non-destructive testing. A list of organizations represented on this committeecan be obtained on request to its secretary.Relationship with other publicat
7、ionsThis document is part of a series which is intended to cover differentapplications of guided wave testing.Currently, BS 9690, Non-destructive testing Guided wave testing, comprises thefollowing parts.Part 1: General guidance and principles.Part 2: Basic requirements for guided wave testing of pi
8、pes, pipelines andstructural tubulars.However, it is anticipated that further parts of the standard will be introducedto cover the interpretation of measurements; the testing of advanced cases ofpipes, pipelines and structural tubulars; and the application of guided wavetesting to other structures a
9、nd components.Use of this documentIt has been assumed in the preparation of this British Standard that theexecution of its provisions will be entrusted to appropriately qualified andexperienced people, for whose use it has been produced.Presentational conventionsThe provisions of this standard are p
10、resented in roman (i.e. upright) type. Itsrequirements are expressed in sentences in which the principal auxiliary verb is“shall”.Where optional recommendations are included, they are expressed in sentencesin which the principal auxiliary verb is “should”. The word “may” is used in thetext to expres
11、s permissibility, e.g. as an alternative to the primaryrecommendation of the clause. The word “can” is used to express possibility, e.g.a consequence of an action or an event.Commentary, explanation and general informative material is presented insmaller italic type, and does not constitute a normat
12、ive element.Contractual and legal considerationsThis publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legalobligations.BRITISH STANDARDBS 9690-2:2011ii B
13、SI 20111 ScopeThis part of BS 9690 specifies the basic requirements for screening pipes andsimilar tubular objects using the guided wave testing (GWT) method, includingset-up, data collection and basic interpretation of the data. It is intended to beread in conjunction with BS 9690-1.NOTE 1 Some bac
14、kground to the GWT method is given in Annex A.This part is applicable to the testing of ferritic carbon and low-alloy steel pipes(tubes used for the transport of fluids) and structural tubulars (tubes used forload-bearing constructions) in the diameter range 1 inch (25 mm) to60 inches (1.52 m), with
15、 maximum wall thickness of 2.2 inches (55 mm).NOTE 2 The term “pipes” is used throughout this document to mean pipes,pipelines and structural tubulars within this scope of materials and dimensions.This part of BS 9690 is applicable to the use of the GWT method using thepulse-echo technique with the
16、transducer mounted on the outside of pipes forwhich the testing is straightforward. Advanced cases, in which the factors listedin Clause 4, items a) to i), are encountered so that the testing is notstraightforward, fall outside the limitations of the scope as given above. Forsuch cases, additional p
17、rovisions are necessary.For some of the advanced cases that are currently not covered by BS 9690 itmight be possible to inspect using specific instructions provided by the GWTequipment manufacturers. These instructions are likely to differ betweenmanufacturers according to the details of the equipme
18、nt. Such instructions arereferred to here as “supplementary instructions”. The intention is that some ofthese advanced cases will eventually be covered by other parts of BS 9690 ascommonly accepted approaches emerge.For those advanced cases that are not covered by other parts, it is necessary forsup
19、plementary procedures to be added to those specified in this part of BS 9690.It is necessary for any such supplementary procedures to be documented andagreed between the inspector and the clients see 5.2, item a).2 Normative referencesThe following referenced documents are indispensable for the appl
20、ication ofthis document. For dated references, only the edition cited applies. For undatedreferences, the latest edition of the referenced document (including anyamendments) applies.BS 9690-1:2011, Non-destructive testing Guided wave testing Part 1: Generalguidance and principlesBS EN 473, Qualifica
21、tion and certification of NDT personnel General principlesBS EN 1330-2, Non-destructive testing Terminology Part 2: Terms common tothe non-destructive testing methodsBS EN 1330-4, Non-destructive testing Terminology Part 4: Terms used inultrasonic testingBS EN 14127, Non-destructive testing Ultrason
22、ic thickness measurementBRITISH STANDARD BS 9690-2:2011 BSI 2011 13 Terms and definitionsFor the purposes of this British Standard, the terms and definitions in BS 9690-1,BS EN 1330-2 and BS EN 1330-4 apply.4 Factors influencing the performance of guidedwave testing of pipesThe following factors can
23、 adversely affect the propagation of guided waves inpipes and/or the ability to interpret the resulting responses from features andimperfections (they are listed in approximate order of severity).a) Generally roughened surfaces, inside or outside.b) Short sections of pipe between major features, suc
24、h as flanges or bends. Thepipe needs to be sufficiently long that it can be tested, in consideration ofaxial resolution and dead zone.c) Bends, in particular sharp radius elbow fittings.d) Welded supports.e) Branches and other attachments.f) The presence of a viscous liquid in the pipe.g) The presen
25、ce of external or internal coatings, particularly if they lead torapid loss of sound energy and hence to high attenuation rates.h) The pipe being buried in the ground.i) A break in the continuous metal path for sound propagation, typically aflanged joint.NOTE 1 Non-metallic paint and epoxy layers up
26、 to 1mm (0.04 in) thick do notnormally affect the propagation of guided waves.These factors affect the rate of loss of the ultrasonic energy, increasing the rateof attenuation, or the degree of scattering, resulting in coherent backgroundsignals (similar to grain noise in conventional ultrasonic tes
27、ting). Their overalleffect is to shorten the diagnostic range which may be achieved for a certainsensitivity level for detection of discontinuities.The following limits shall therefore be applied for this part of BS 9690NOTE 2 Testing beyond these limits might be permissible according to therequirem
28、ents of other parts of BS 9690. If not, supplementary procedures may beused, if available.1) The factors in items a), f), g) and h) cause losses from the transmitted pulse,which is observed as high attenuation and/or raised background levels ofscatter. If severe, this can lead to signals which canno
29、t readily be interpretedwithout special procedures. In tests where the attenuation rate exceeds1 dB/m the requirements of this part of BS 9690 shall be deemed not tohave been met. See 10.1 for a method of determining the attenuation rate.2) Short sections of pipe item b): The long wavelengths and to
30、ne burstexcitation used for GWT produce pulse lengths which can be 0.5 m long ormore. This limits the axial resolution possible. GWT is therefore notoptimized for testing short lengths of pipe. See item i) regarding flanges.This factor also limits the proximity permitted between the transducerpositi
31、on and features (see 9.1.3) such that it might not be possible to testthe whole length of the pipe section, even if more than one transducerposition is used.3) Bends item c): Testing shall not be carried out beyond an elbow fitting. ToBRITISH STANDARDBS 9690-2:20112 BSI 2011test the region beyond a
32、fitting, the transducer has to be moved to a testposition on the other side of the bend. This restriction does not apply to”pulled” bends where a straight length of pipe is formed into a curve.4) Welded supports item d): Testing shall not be carried out beyond a weldedsupport if the amplitude of res
33、ponse from it is less than 6 dB lower than theweld DAC curve.NOTE 3 Welded supports can generate reflections that are both large inamplitude and axial extent. The reflections are composed of direct reflectionsfrom the change in section at the front and back of the support withcombinations of signals
34、 from internally within the support that are continuouslyradiated causing a large tail on the direct reflections. The internal signals fromthe support or structures rigidly attached to the support arrive at a distancebeyond the support and can have amplitudes an order of magnitude larger thanthe sup
35、ports direct reflections.5) Branches and tees item e): Testing can be carried out beyond a branchwhere the diameter of the branch is not greater than half the diameter ofthe pipe being tested. In such cases the interaction of the guided wave withthe branch is such that the onward travelling pulse is
36、 not significantlydistorted.6) Flanged joints and other breaks item i): Such breaks do not allow thepassage of sound across them, so that testing beyond these is not possible.5 Information and requirements to be agreed anddocumented5.1 Information to be supplied by the client5.1.1 The following info
37、rmation to be supplied by the client shall be fullydocumented. For compliance with the standard both the definitive requirementsspecified throughout the standard and the following documented items shall besatisfied.a) Pipe nominal diameter and wall thickness.b) Standard to which the pipe is manufact
38、ured.c) Actual pipe outer diameter if manufacturing standard is not known, or ofnon-standard size.d) Material (ferritic steel, austenitic stainless steel, etc.).e) Pipe type (spiral welded, seam welded or seamless).f) Geometry (straight lengths, bends, Ts, welded or flanged construction).g) Type and
39、 location of any supports (simple contact, welded,doubler plate, etc.).h) Whether pipe is above or below ground, or has an external sleeve or casing.i) Clearance between ground and adjacent pipework, or other obstructions.j) Coatings, if present (internal/external, type and thickness).k) Insulation,
40、 if present (type and ease of removal for transducer locations).l) Operating temperature and pressure at time of test.m) Pipe contents.n) Trace heating, if present (electrical/steam piping, number of traces, stand-offdistance from pipe).BRITISH STANDARD BS 9690-2:2011 BSI 2011 3o) Any special requir
41、ements for preparation of the surface, includingrestrictions on methods or transducers which may be used.p) Any special requirements for training (see Clause 7), operating proceduresand personal protective equipment required for access to the inspection site.NOTE Additional useful information may in
42、clude: approximate distance between welds or flanges; general photographs of pipework in question; details of any known/suspected damage and mechanisms; results of any previous GWT inspections, or other NDT; the direction of flow of the pipe contents, if applicable.5.1.2 The organization responsible
43、 for performing the test shall provide thefollowing information.a) The minimum clearance requirement for fitting and removing thetransducer at each test location.b) Length of pipe surface to be prepared for attachment of the transducer(see 9.1.1).5.2 Items to be agreedThe following items to be agree
44、d between the contracting parties are specifiedin the clauses referred to and shall be fully documented. For compliance withthe standard both the definitive requirements specified throughout the standardand the following documented items shall be satisfied.a) Supplementary documented instructions, i
45、f required see Scope; Clause 6,item q); Clause 7; 10.1, item f); and 10.3.b) The permitted methods of surface preparation see 9.1.1, item b).c) The threshold for the reporting of indications the “call level”:see 10.2.2, item e).d) How test results are to be reported see Clause 11, item j).6 Test pro
46、cedureGWT shall be carried out in accordance with a written test procedure, which as aminimum, includes the following.a) Description of the pipe to be tested.b) Reference documents.c) Qualification and certification of test personnel.d) State of the pipe to be tested.e) Region(s) to be tested.f) Pre
47、paration of the surface(s) on which the testing is to take place.g) Description of the GWT equipment.h) Description of any ancillary equipment required to test and to calibrate theGWT equipment and to perform associated tests, such as wall thicknessmeasurement.i) Acceptable environmental conditions
48、for performing the test.j) Calibration and settings.k) Description and sequence of test operations.BRITISH STANDARDBS 9690-2:20114 BSI 2011l) Determination of the diagnostic range.m) Recording and evaluation levels.n) Characterization of discontinuities.o) Acceptance criteria.p) Reporting requiremen
49、ts.q) Supplementary procedures, if required see 5.2, item a)7 Personnel qualificationPersonnel performing GWT shall be qualified to the appropriate level on thetopic of GWT according to a certification scheme which meets the requirementsof BS EN 473 or equivalent as agreed.Inspectors shall only inspect pipes within the scope of their certification.Inspections shall normally be conducted by an operator qualified at least toGWT Level 2. Level 1 inspectors may perform certain tasks, as defined by therelevant certification sche
