ML20052G145

Forwards Approved Draft Ansi/Asme OM-3 Re steady-state Piping Vibration Acceptance Criteria.Ser Open Issue 3.9.2 Now Closed Based on Encl Info

ML20052G145
Person / Time
Site:	Clinton
Issue date:	05/10/1982
From:	Wuller G ILLINOIS POWER CO.
To:	John Miller Office of Nuclear Reactor Regulation
References
U-0477, U-477, NUDOCS 8205140349
Download: ML20052G145 (76)

Text

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/LLINDIS POWER 00MPANY g2g95_39y_5 500 SOUTH 27TH STREET, DECATUR, ILLINOIS 62525 May 10, 1982 o

g Mr. J.

R. Miller, Branch Chief Standardization & Special Projects Branch ggCEll/gg Division of Licensing Office of Nuclear Reactor Regulation 9

"U4)'y O U.S. Nuclear Regulatory Commission-8

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Washington, D.C.

20555

Dear Mr. Miller:

W Clinton Power Station Unit 1 Docket No. 50-461

Reference:

SER Open Issue 3.9.2, Steady State Piping Vibration Acceptance Criteria The attached standard, OM-3, has now been approved by the American Society of Mechanical Engineers.

It specifies 80% of the endurance limit (Sa) from Appendix I to the ASME Code as the acceptance criteria for the steady state piping vibration stress limit.

Illinois Power Company is applying this standard on Clinton Power Station, and on this basis we consider the SER open issue from article 3.9.2 to be closed.

Sincerely, G. E. Wuller Supervisor-Licensing Nuclear Station Engineering "goPEW/lt Attachment cc:

J. H. Williams, NRC Clinton Proj ect Manager H. H. Livermore, NRC Resident Inspector Illinois Dept. of Nuclear Safety 0%\\

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Draft 5, Rcv. 0 APR 29 1982 f

ST N bib ERlNG DRAFT DEPARTMENT CAUTIC:: !!OTE:

Ihis docu=ent is bein;; prepared and revicued and has not been approved by A':SI.

It is subject to revision or withdrawal before issue..

REOUIRD!EtirS FOR PRIOPERATIONAL AND I'i!TIAL STARTUP VIBRATION TESTING OF NUCLEAR POWER PTANT PIPI'!G SYSTDIS ASME CO'e!!?rEE ON OPERATION & MAI:!T"'!A!!CE 07 NUCLEAR PCITER PLiNTS s

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' NOTICE i

THIS XC'JMENT IS A DRAFT '4HICH REPRESENTS ~40RK 3EI2:C 00N SY AN ASME TECHNICAL CC:"d.!~ TEE AND '4HICH IS AIMED AT CCEMTI :C X! ANSI STMIDARD.

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[T IS FURNISHED AS I'IFORMATIONAL M *~*2C[AL CNLY.

TilF. USER IS CAUTIONi.

rtAT Ti!IS LS NOT MI APPRO'JED STNIDARD AND CAtiturr BE ASSUMED T. FLECT Tile POSITION OF ASME, NOR ANY CCt9fITT7.E, C't0UP, OR SO '

. ASSCCIATED '4ITH ASME.

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70REWCRD Incroduction this scandard provides general requirements for the assessnenc of piping

vecem vibrncica for nuclear ;over plancs including ASME See

ten III and applicabla ANSI classified syscams.

1: includes steady-scate and

ansien: vibr::1cn :2 sting and cor:ssponding accuo ance cri: aria, inscrumencacion and measurement :echniques, and recommendacions for correc:ive ac icn wnen required.

This scandard is applicable for vibracion qualificacion and design verificacien, during preoperacional and ini:ial 3:ar:us casting, of piping sys e=s which require :esting by the nuclear pcVer plant g

Saf ecy Analysis Recor:, Design Specificacien, or other governing Jacuments.

n adci:icn, this scancard =ay serve as a guide f or assess-ment of vtbracten levels of applicable piping systa=s during planc operacion.

Ceneral This ::andard is one of a series of nuclear power plant :esting scandards; it was developed as a guide for vibra:ica :ascing and =ent:oring under the sponsorship of :he American Sccie:7 of Mechanical Engineers (ASME) e an effor: by :he Nuclear Codes and Scandards Opera:1ons and Maintenance Coc=1::ae.

This c:=mit:ce has been char:ered :o idancify, levelop, maintain, and review Cades and Scandards censidered necessary for :he sara and efficient operacien and =ain:anance of nuclear pcVer

.iLines to assure scrue: ural and func:1cnal adequacy.

• n February,1976, che ASME Operaciens and Maintanance Ce=mi::ee

.:ablished :he Subc:=mi::ee on Vibracien Meni: ring under whcse

'urisdiccion :his scancard was prepared.

The Subgrous on ?iping Systems

,ponsible for development of :his scandard was establisned in

• reh, 1977.

The previsions of :his standard apply direc:1y to :he

' ars and Operators of nuclear pcVer plancs.

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U documenentien pertaining :o a specific planc, s:2: aments such as

"'m pioing systems are being ested in accordance vi:h ASME Nucica

• ":r t:1cn Scandards may be =ade only provided :ha: :he sandatory

""quirements of :his standard have been satisfied for each siping

' tem covered by :he ASME Scandard.

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Standard ?ecconsibili:/

This Piping System Vibra: ion Tescing Scandard was prepared by a Jub.;roup including the following personnel:

J.S.G. Williams, Chairman A. J. Ayoob, Vescinghouse Elec:ric Corporacion -' ' '.

D._.A. DesMarais,*. Scene L Webscer Engineering Corporacian_,

K. Khu:sie, General Elec:ric Company G. T. Ki :, Sargen: 1 Lundy Engineers L. Memula, 3echtel Power Corporacion J. R._Rajan.. U.S. Nuclear Regulacory Cec =1ssion H. J. Tha11er, Nuclear Service Corporacica J.S.G. Williams, Tennessee Valley Authort:7 J. C. Wachel, Southwest Research Insci:uca The ASME Sube==mi::ce on Vibracion Monitoring had the following neeber-ship ac :he ti=a of approval of this scandard.

G. T. Kic:, Chairman J. R. Hoff=an, Secrecary G. 3 ohm, Wescinghouse Elec:ric Corpora:1on A. J. Oster, Stone & Webscer Engineering Corporation R. E. Hucchings, General Electric Cc=pany J. F. Hoffnan, Yankae Accmic Elec:ric Cersany G. T. Kit:, Sargent & Lundy Engineers R. C. Krycar, Oak Ridge Nacional Laboracaries

3. T. Lubin, Combustion Engineering, Incorporaced J. M. McBride, 3echcal ?cuer Corporation G. C. Millman, '.;US Corporacion

?. J. Pekrul, Rockwell Iacernational J.S.G. Williams, Tennessee. Valley Authori:7 G. Eigler, Science Applicaciens, Incorporaced

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The AS::E Opuracien and Maintensaco Commi:: e had :he following membership ac :he cimo of approval of chts scandard:

W. P. Johnson. Chnf rman

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Secrecary

' K. I,. Barck D. G. acey, Catalytic, Incorporated L. Chockia, General Elec:ric Cocoany S. L. Dal:rof f, Philsceiphia Elec:ric Ceepany J. R. Duck, Nuclear Insurance Consul:ancs T. W. Fitzgerald, NEL-PLA S. A. Grimes, Americsn Electric Power Service Corporation W. P. Johnson, Yankee Acomic Electric Company F. Kelly, EDS Nuclear G. T. K1 :, Sar;ent & Lundy Engineers

3. Koh, Westinghouse Elecerte Corpors:icn J. M. Kufel, Northeasc Utili:1es Service Campany J. D. Phinney, 3abcock i NLicox J. Sniezek, Nuclear Regutscory Commission W. C. Sommer, Surns & Roe J. Stacey, Yankee Accmic Elec:ric Corporacion R. J. Walkar, Cembustion Engineering W -5 ::m dzt R m :-0 2 L. E. Williamson, Souchern Survices Suggestions for improvements as gained in :ne use of :his s:sndard will be welcomed.

They should be acne to :he Se:recary, ASME Vibration Monitoring Subcommi::ee, The American Society of Mechanic:1 Ingineers, United Engineering Center, 343 East 17th Streec, New York, New York, 10017.

This se:ndard was approved by The American Society of Mechanical Engineers Subcom=1::se en ?erf arnance and Ccemi::ee on Cperscion Main:enance.

was subsecuently.mpproved and designaced by The A=erican Nacionsi Scandards Insci:uce en i

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No part of this document may be reprocuced in any forn, in an 314c:renic recrieval system or otheteise, w1:houc the prior wri::en permissien of the publisher.

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i BY I'E AMERICXi SOCIITY CF MECEMIICAL CICI:!EZ25 d

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All Rights Reserved Princed in U.S.A.

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REQUIREMENTS TCR ?RECPERAT!C:!AL a'ID IMIT!.*.L ST.V. L'O VI2.MTICM TESTIUG OF NUCLEAR ?C'iER ?LulT

?!?ING SY2TEMS TITLE.

Abstract Foreword ASME Copyright Page 1.0 Increduccion 2.0 Definicions 3.0 General Requirements 3.1 Classification 3.1.1 Staady-State 71bracion 3.1.2 Transienc Vibration 3.2 Monitoring Require =ents and Acceptance Cricaria 3.2.1 Vibration Monitoring Cecup 1 J

3.2.2 Vibracion Monicering Group 2 3.2.3 Vibration Monitoring Group 3

4.0 Visus

Inspeccion Meched i

4.1 Objectiv-i 4.2 Evaluacion Techniques 4.3 Precaucions 5.0 Si=plified Method for Qualifying Piping Sysca=s 3.1 Sceady-Scace vibracion 3.1.1 Displace =ene Meched 5.1.2 velocity Meched 5.2 ::ansianc Vibracion i

5.2.1 General Require =enes 3.2.2 Instru=entacion 5.2.3 Measure =enca and Oricaria for Acceptance 5.3 Inaccessible ?iping (3cch Sceady-Scaca snd Tr:noient) vii

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6.0 Rigorous verificacion Meched 6.1 Modal Response Technique

'6.1.1 Ground Requirenenes 6.1.2 Tesc Requirements 6.1.3 Data Processing 6.1.4 Tesc/ Analysis Correlacion 6.1.5 Evaluacion of the Measured Responses 6.2 Measured Stress Technique 6.2.1 GeneralRequiremencs 6.2.2 Evaluacion of the Measured Responses 7.0 Instrumencacion and Measure = enc Techniques 8.0 Correceive Accion Appendix A Instrumencacion and Measurenenc Techniques Appendix 3 Analysis Mechods Appendix C Tese/ Analysis Correlacion !!achods Appendix D 7elocity Cricerion l

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's 1.0 INTRODUCTic:t L. L Scone This scandard provides general require =enca for assesa=cac of piping system vthrat ton for nuclear power plancs includtny, ASME Saccion III and applicable AllST classifted systems.

Cc inetudes scency-scar.e and cranstent vibracion coscing, acceptance criteria, and recommenda-cions for correceive action when required.

The scandard is applicao' la for vibration qualification and design verificacion during preoperacional and scarcup cescing of piping systems which require :escing by the nuclear power planc safety analysis rept-aest;n specificacionx or other governing doct=er.ca.

• In addition, this scandard may serve cs a guidu for assessment of vibracion levels of appliechic piping systems during plant operation.

4 s

r 2.0 DEFINITICNS

2.1 Owner

The organizacion responsible for :he operacian, =sincenance, safety, and power generacion of the nuclear power planc.

2.2 Cesign specificdcton:

The document provided by the owner as' required by NCA 3250 of the ASME El! for the co=ponent/syste= vhica contains require =enct :o provide a co=plete basis for che construe:1on of the co=ponenc/systa=.

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2.3 Maintenance / repair / replace =ent: Ac: ions taken to prevenc ve correct deficiencies in the syste= operation.

2.4 Syste=: An asse=bly of piping subasse=blies and co=ponents whose li=ics and func:1ons are defined in 1:4 design specificacions.

2.5 Recore drawing set:

n!e set of draeings which define che syste=s layout and support configurs:icn at :he :1=e che syste= is placed in service for cascing.

2.6 Sceady-sesce vibration:

Repeci:ive vibrations which occur for i

rela:ively long periods of ti=e during nor=al planc opers:1on.

2. 7 Transien: vibracions:

Vibracions vnich occur during relatively short periods of :i=e.

Ex2=ples of ::snstant sources of vibracica are:

pu=p ac:uation and pu=p avi:ching, rapid valve opening or closing, and saf ety relief valve operscien.

2.3 Nor=31 operating condi: ions:

The service condi:icns :he sysce=

vould experiehcc when perfor=ing i:s incanded function.

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2.9 Test condi: ices:

The service cond1:fons experienced by the system when undergeing tests to ar,sure 1:s incended func:icnal ability.

2.10 Teuc :pecificacion:

The docu= enc or doc==ents prepared by the evner or his assignee which =ee:s the requirc=ents se: for:h in sec:1on 3.0.

2.11 Design verificacion:

The process during which :he design adequacy of che system is validated.

This includes checking the record drawing set against the inscalled system and evaluating actual system behavior against applicable analyses and/or acceptance cri: aria.

2.12 Protocype - A system built en :he basis of an original design for which there are no previous system :ese results available.

2.13 Duplicace - A system buil: en the basis of a previously used and preven design for which tesc results are available.

i 2.14 Preoperacional Testing - Test activi:1eu perfor=ed prior to ini:ial fuel loading.

2. 15 Ini:ial Scar:up Testing - Test ac:171:7 perfor=ed during or following ini:dal fuel loading, but prd or :o ec==ercial operation.

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These activi:1es include fuel loading, precri:ical :ests, l

ini:1al cri:icali:y, low power ceses, and pcwer accension tests.

2.16 Operacional Testing - Tes: ac:1vi:ies perforned subsequent :o ini:ial startup :esting, e.g., :esting perforned during ce==er: al operation of the plant.

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c 2.17 ASE Code - ASE Soilar and ?ressure 'tessel Code - Sec:1on I:I, 2.13 Test hold points:

System operacing cond1:1cns for which :ese infor=a-tier..i:2. o be..collec:ad; e. g., w1:h the reac:or ac lC: power, wich

he system at full flow, etc.

2.19 Quali:7 Assurance: All : hose planned and systaeacic ac:icns necessary to provid_e adequate confidence chac an item or fac111:7 vill perform satisfactorily in ser rica.

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3.0 GE:!E?at REOUIREP.E:ITS The Ownce shall determine che portions of piping svstems to be :ested Chssity Yhest SVCH.Mc s nes the vCorahan xnil o rna,yrru,ns ui SnLf) der *iord in cho /attowing ea.rion.

"he min imum..- 9 ra l canutr emen:4 for the e tassif tascion by groups are provided in suosec:ien 3. L; however, che Owner may place a system into a more 3:ringene vibracion monitoring group (7P.C).

Vibration condicions are classified into s:cady-scace and ::ansiene vibracion cacegories.

A system may be classified in:o one vibracion monitoring group for steady scace vibrations and into another group for cransient v ib ractens.

The :estirts requirements, acceptance criteria, and reco=mendacions for correc:1ve ac: ton associ.tcad w1:h

hese cacogorios are provided be Lov.

The vibracion testing and of vibracion levels may be condue:ed during preopernciona L assessment and int:ial.4cartup tescIng or during olanc operation in accordance vi:5 the requirements of the :est spescificacion.

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For preoperacional, ini:ial startup, and operacional :escing, a tese specificacion shall be prepared which vill include as a minimus:

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l Precest requirements or :endi:lons i

Type :est (i.e., steady.4cace or ::ansienc)

Systems :o be tested Test condi: tons l

l Measurements (including visual observation) to be made Accepcance cricaria

Tcsc hold points Instrumentation to be u.5ed (including inscru=en:s specificacions)

Coverning documancs and drawings Data handling and scorage Quality control and assurance System res'coracien r

Precautions The ca.*t specificacions shall be wit::en in a sanner to ensure that the objectives of the cases are satisfied and that resul:s obtained are consertative.

Prior to testing, e. inspec:icn of :o:ponents and supports shall be nade to verify correc: inacallacion according :o the record drawing set, specificacions, and appropria:a codes.

'" hen cast resulcs are to be correlated :o specific analyses, cast condi:1cus and neasure=enes should be sufficiencly specified to ensure :hac the pars =ecers and assu=pcions used in :he analyses are not violated,an( : hat h e correlacion between casts and analysis h,g d Ql 5h44 rasects confirms the validi:7 of the analysis andh.ndicaces :hac v.

T.F A 4 d kesu'lbe r,t.(.['

t/e" the analytical resul:a are ccuserva:1ve.

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,d. < 3ud<. 'u when fAe m e'c.S urel ifA-fv-w, Me te.;b e,,,,h indicates that the actua4 orci;g 'une:1on is r -

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M.i.. y-covered by :he forcing fune:1cus used in :he a conser.acived4 5svi

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the analytic daca should be =cdified or ccusertatively scaled prior to cor clating':he :est and analysis risul:3.

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The vibr:cion monitoring requirements and acceptance cri: aria arc defined in subsec:icn 3.2.

If the cast data exceeds :he value t.

specified in the hold point sec:icn of the :csc specificacion, two options are,available (1) further cescing or evaluacion cu a ore rigorcus = ached or (2) correceive ac:1on should be'caken as described in see:icn 3.0.

Cogni:an: engineering personnel shall par:1cipace in the develop =en:

of test specificacion requirements, selec:fon of inst = men scion, establish =ent of accepcance cri:eria, review, evalus:1cn, and approval of :est resul:s.

Selec:1on of :he locacions of measuring devices and the :ype of measurements :o be made shall be based upon pipLng stress analysis, response of a similar system and/or experience gained :hreugh tescing of the subject system and shall reflee: any unique operational characteristics of :he system being :ssccd.

Ivaluacion of :he cas:

data shall censider charac: eristics of :he =essuring devices used.

3.1 Classifics:icn t

Piping syncem vibrations are classified Dr.cc rvo categor es:

(1) steady sca:e, and (2) ::ansienc, as defined in see:1ons 2.3 and

2. 9.

'Ji:hin each applicabic category :he ?iping system shall he classified LF.co one of :he :hree vibra:1:n =ent:oring groups according to che ert:erta presan:ed La subsee:1ons 3.1.1 and 3.1.2.

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5 Piping syscoes which are inaccessible for visual obccr/acien or neasurement using portable devices, during :he condi:1cns listed in the test specificacion, shall be classified in:o ei:hcr '."MC 2 or VMG 1.

In addi: ion :o the requirements. presented in subsec:icns 3.1.1 and 3.1.2, the safety and/or power generation func:1on of the systes 1:.: ;; _..

should also be censidered when classifying :he system in:s :he vibra:1on :eni:'oring gr ups.

r 3.1.1 Standv-Scace Vibrs: ten 3.1.1.1 Vibration Meni:crine Creue 1 Che monitoring program required for systems evaluated in this group typically Lavolves sophistica:ed moni:oring devices and axtensive data collac:1on :o accuracaly decarmine vibraccry pip.

stresses or other specified componen: IL 1:stion.

'4 hen accurata = essure =en: of :he syscam rasponse charac:aristics are required, the :echniques and devices i=pliad by the requirements for :his vibracien :eni: ring gr up shall be employed.

Oe ar:1nacion of mode shapes, zodal response nagni:udes and :ocal system response is possible using :hese evaluation :echniques.

All portions of piping sysca=s which experience sceady-sca:e vibratiens and meec ne of :he foll wing requiremen:a shall be classified in (TMG 1 and shall zee: :he acceptance cri:eria of subsection 3.2.1.

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3.1.1.1.1

?iping sy : ems which exnibt:

response not charac:eri:cd by simple niping modes (e.g., relatively s:1ff piping =cun:ed between large sof:1y scunced equipcent).

3.1.1.1.2 Piping systems for which :he seched of VMG 2 and 3 are not applicable based on lisi:stica given in see:1:ns 4 and 5.

3.1.1.2 71bracion Moni:orine Creus 2 The methods and devices employed in the evaluacion of vibracd

.cn monitoring group 2 provide a sesne of ascer:sining whether the piping systems are v1 bracing, and provide a means for as'ce'r the maxi =um resconse at a given location.

All por:1cns of piping syscems which eet one of the following recuirements shall be classified in vibracien =oni:oring group 2 and shall meet the acceptance c 1:cria specified in subsection 3 2 2 3.1.1.2.1 All piping systems which may exhibi: significanc vibracion response based en past expertence with similar syste=s or similar system oceracing conditions.

3.1.1.2.2 Piping sysce=s for unich :he eched of VMG 3 are not a:plic bl a e based on li=1:acion given in section 4 3.1.1.3 vibracion Meni:crine Ceaue 3 The visual me: hod employed in :he evaluation of vibracion moni:oring group 3 ta most funda=cn:al and provides :he cose simplified means for de:crnining whacher any significanc

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vibracions exist in the sys:cm.

Evaluation of vibracion levels using this method is based upon enperience and judg=ent ar.d provide an'ac:eptable basis for asseas=ent.

If firm quan:1:a-cive assessments are required, che methods in vibra:icn moni:oring groups 1 or '2 should be e= ployed.

All portions of piping sys: ems which =ese one of the folleting require =en:s shall be classified in vibracion moni:oring_ group.3.. _ _.

and shall see: the acceptance cri:eria specified La subsee:1on 3.2.3.

1 3.1.1.3.1 Systems falling in VMG 1 or VMG 2 classificacion for which neasurements or prior tes: data are available on prococype or duplicace systems and for unich the minimum unaccsprable vibracions are observable.

3.1.1.3.2 Portions of ASME Class 1, 2, and 3 and ANSI 331 piping systeas which are not expected to enhibi: significant vtbrati nal resconse based on pasc experience vich si=11ar.sys: cms or system operating cond1:1ons.

3.1.2 Transian

vibracien Table 3-1 presents *sc=e exampics of transien:

l condi:1:ns :o which systecs may be subjec:ed.

3.1.2.1 V;bencion. Ment:crin: Greun 1 1

Portions of piping sys: ems vnich enperience ::ansien:.ibra: ions and eet :.].e following :2quir: enc,shall be classifiec in '.?.c :

and shall ne2C acceptance cri:cria specifiad in subsection 3.2.1,

s 3.1.2.1.1 Systa=s which from pasc planc operacion experience are known

o experience sir.nifican: dyna =1c ::ansien: condi:icas due :o I.

che inherent nature of cocponent design, system operacion, or systes design features, for which a cransient analysis is not perform 6d.

3.1.2.2 Vibracion Moni:orine Cecue.2 Portions of piping sys:c=s which enperience cransient vibraticas and meet the following requirement shall be classified in 7MG 2 and shall ee: acceptance crt: aria specified

'.a subsee:lon 3.2.2.

3.1.2.2.1 Systems which are designed and analy:ed for known ancicipaced dynamic leading c:ndi:1ces and for which the applied loading (i.e., fluid or =echanical) is based upon e:hodology which is known :o conserva:ively predic: che cransient forcing func: ion and corresponding scrue: ural response.

3.1.2.3 Vibra:icn Moni:orine Groue 3 All portions of piping syste=s which experience ::ansient vibrations and zee: :he folleving require =ents should be classified in VMG 3 and shall eet :ne 2ccep ance cri: aria specified in sucsec:ica 3.2.3.

3.1.2.3.1 Systems which undergo ::ansiene vibracians during : heir i

operacing life (e.g., systems subjec:ad :o pu=p startup t

transients, valve opening or closure) and which by past enperience vi:n si=1lar system or syste=s operating condi:lons are not enpec:ed :o e:cnibi: significan: vibra::enal respence.

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S 3.2 Meni:ortne 2e~2 ire ent:,,nd Ace o: nee Cet eria Special ac:encien should bc given to the precautions listed in subsec:1cn 4.3.

The acecptance cri:eria presented in this subsec:icn are based upon the following assumptiens.

The Owner ay invoke.Less stringent critaria provided sufficient justificazion is 3iven.

More stringent critaria shall be invoked if the following assu=pciens are deemed inappropriate for :he system under review.

Assuenciens; Vibracions cause maxinun stresses within :he elastic range, a.

therefore no penalty for pikstic cycling is incurred.

b.

Thermal ::ansien: effects, if they exisc furing :he vibracion incident, have already been considered in the piping system evaluacion.

The nasarane s:resses caused by pressure flue:uaticus, alone, c.

are insign111:an: La ce=oarison :o the stresses caused by :he vibraccry =0 ents.

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The usage fac:ce frem the vibra:1on incident does not signi-ficantly affec: :he :==ulative usage fae:ce calculaced for other predefined ::ansient condi:icus.

The ASME B&PVC Section III strain controlled fatigue curvec e.

reprecca: the S-ti fatigua characteristics for the material and loading considered, i

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3.2.1 Vibrstien !%nitorin Orino L J. 2.1.1 The vibration response of group 1 sysca=.s.shal.l be evalus:ed using-che cchods and devices listed in see: ion 6.0.

3.2.1.2 For secedy-sca:e yibracion, che :::ci=um calcula:ed al:arnacing sc ess inconsi:y, S

, should be li:1:ed as defined.below:

For ASME Class i. kiping syste=s, a.

C.,K.,

f S

= -- M 6.3 Sel alt Z

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C2 See ndar/ stress index as defined in :he

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ASME C0de K2 L **1 **r***

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• ii#*

i* *h" ASM Code M

Maximum :ero :o peak dynsmic soc:ene loading

=

due :c vibe :1cn only, or in ce=bina:ica it:n other loads as required by :he sys:am *:esi.v,.

Specificacien Sel Indurance 11=1: (Sa) from figure I-9.1 or I-9.2

=

'N 1 of the ASME C0de, Appendi:: I. +

k I'w Lkie r s h t.i.

v.:.n e c d e 1e tib

• )

CII~ U imc O,

m

. - -. - =

J7

t

\\

i TANGENT UNE PIPE AND ELSCW 8 l/ CUT OF PLANE CEFLECTICH

(

4 s

t\\

+ '4

(

h 1

,/

\\

PPE CENTER URE IN M ANT i

OEFLECTICM

,v ;~R _

/

/

Y s

fI WIE i

FIG. 5-2 OE.: LECT 1ChN MEASUREME.NT AT i

INTERSECT!CN OF P!PE MO EL30W I

i l

d

t

~

\\

K :.003 CHARACTERISTIC SPAN

_S S

~

J g

' N_

f e

FIG.5-3 SINGLE SPAN DEFLECTION MEASUREMENT l<

t M

K=.030

. _ _ _ - = -

1 l

' CHARACTERISTIC l

SPAN FIG. 5-4 CANT 1 LEVER SPAN DEFLECTION MEASUREMENT l

l I

I

x Cf IN Pt. AN E CEFLECTICN t

M g

6 g

M: 030 g

\\

CH AR ACTERISTIC

\\

SPAN

\\.

\\

f1 FIG. 5-5 CANT 1 LEVER SPAN-ELSCW-SPAN IN PLANE DEFLECTION MEASUREMENT l

s' tN Pt ANE CEF:.EC TICN i

l M

1. ~~

" _

• _'2 0

i l

l l

ia

- t.

=l CH AR AC TERIS TIC l

g if GUICE

~ ~

SPAN g lp I

I, e

!C.

FIG. 5-6 CANTILEVER SPAN-ELSCW-Gul0ED SPAN IN PLANE CE LECTICN MEASUREMENT

1 l

O

~~

/

y

1.

~

?

~ ~ ~,7 I

_,L 2 L2 LESS THAN.5

~

1 l CHARACTERISTIC 7

L I SPAN L SEE FIG. 5-9 FOR K

?

FIG 5-7 SPAN-ELSCW-SPAN OUT OF PLANE DEFLECTION MEASUREMENT SFAN RATIC LESS THAN.5

/

m

.l l

Q-.

J

/, '

f'

,J /

l

/

L2 l

L I

' CHARACTER 1STIC SPAN L L2 BETWEEN.5 ANO l.O i

L i

i SEE FIG. 5-9 'Cft K F1G. 5-8 SPAN-EL3CW-SW44 OUT CF PLANE DEFLECTION MEASUREMENT SPAf4 RATIO GREATER THAN.5 i

l I

FI

1 I

l i

I e

.0 3 I'_

.02 l[

Y I

0 0

0.2

0. 4

0. 6 0.8 1.0 La L i FIG. 5-9 S P AN-EL20W-SPAN OUT OF PLA N E CONFl G UR AT:0 N COEFFIClENT VERSUS RATIO OF S PANS On = K: :

5

~

W

I

--}..--,----_..-

.. ~

~ ~. - - -.. ~

t 5.1.2 - Veloci:r Meched

\\,

5.1.2.1 Cenersi Raouiremenes We mech 5 requires consecutive measuremanes of veloci:y at various poides on :he piping syscas'in order to-locate che point which is exhibicing the =aximum vibracory veloci:y.

Onca this point is located, a final sessurement of the max 1=um velocity (Vaan) ac that point is ciada and compared with an c.11ovable peak velocity h/,yy) as given in paragraph 5.1.2.4 The cri:erts for acceptab111:/ is chac 7

sax all 5.1'. 2. 2 Inscr.:mencae ten The instrumanc used.hould be portable and capabic of making-.

a number of consecutive velocity =easurements ac various potacs e

on the piping. The instru=ent should be capable of indica:ing a

ace of the actual velocity-ci=a signal frca which :he =sxt=um veloci:7 can be read. This =ay be achieved by readeu: devices such as a 'cachede ray tube or a paper charc recorder.

A ' :: ens-cively, the 1:scru=ent could nave a holding circui: which *.ould result in a =ecar reading of :he =ax*-"- veloci:y.

- - ~.

,y

,,-,--m

5.1.2.3

?recedure Inicial nessure=ents are to'be taken ac points on the piping which appear to be undergoing the largest displacenents. These vill nor= ally correspond to points of highese velocity. Ac each such point, neasure=en:s can be caken around che circumference of the pipe to find :he nagni:ude of the nax1=um veloci:7

easurements may be confined to direccions perpendicular :o che axis of the pipe at that poinc.

The maxinum veloci:y should be obtained caly from :he actual velocicy-cine signal. The readouc of :he signal should be of sufficient duracion to ensure a high probability chac the max 1=um velocity has in fae: been obcnined for thac poinc in that direccion.

5.1.2.4 A11ovable Pesk 'telocity The expression for allowable velocity is:

1 t.

3.9 x 10~3 (o.asel) 7 all C

2b V

= Allowable veloc1:y, inches per second g

3,3, C, K, are defined in see:1on 3.2.1.2.

The secondary stress 2

index, C,, and the l'ocal s:ress index, K,, are associated v1:h i

the point of =ax1=um stress, and not necessarily vi:h the point of.ax1=um veloci:7 This veloci:y" crt:erton is consis:ent vi:h the deflec:icn cri:erton for a fixed end bean.

i

/

.. ~ -.

f C = a correc:ica factor to compensace for the effec: of g

I concentrated"veights' along the characteristic span of che pipe. See figure 5-f0.~

'~

~...

C3 = a correction fac:ce 4.ccouncing for pipe concents ar.d insulacion.

W W ;g ) 1/2 p

n

= (1.0 + W

+

4 where W = veight of the pipe,eer uni: length (ib/f:)

W. = veight of the pipe concents per uni: leng:h (th/f:)

e 7

= the weight of :he insulacion per uni: leng:h (lb/f:)

733 C = 1.0 for pipe without insula:1on and ei:her empty or containing 3

steam.

C4 = Corree:ica fac:or for end :endi: ions different from fixed ends and for configuracicus different from scraight spans.

C - 1.0 for a scraight span fix4d at both ends, but conservative 4

for any practieni end condi:1ons for straight spans of pipe.

C4 = 1.33 for canc11 aver and st= ply supported pipe span.

C., = 0. 74 for equal leg Z bend.

C4 = 0.33' for equal leg *J bend.

Non=andatory appendi:c 3 presents ens =plas of correction factore C and C for typical piping spans along with a cocoinacion of 1

4 these factors to provide sn ini:isi screening =eched.

5.2 Transient vibracion This section defines a meched for evaluation of vibration at the piping syste=3 subjectad cc trancian: lenda f or wn t en the e x:'oc ~ <'t

6 I.

1. 0 ~t

0. 9 p

0, 8 -

~

i

'i 0, 7' it u 0. 6 2

l i

,1

• 0. 5 1

5 b

b

0. 4

\\

,2

0. 3

0. 2 -

0.1

~

t 0

w 0

5 10 15 20 25 Ratio of Concentrated 'Jeigh: :o Charac:er13:10 Span '4eight FIGURE 5.10 CCRRECTION FACTOR. C 1

O ia

response under the anticipated cransienc loads is decernined by analysis. Piping systems that are not sulcable or adaptable to chese methods shall be evaluated by the sechods of seccion 6.0.

5.2.1 General Receirements This mached requires chsc a dynamic analysis of the piping syscem subjected to che expected transient loads has been perfor=ed yielding the system dynamic responses.

Further= ore, c.se analyc-ical responses must be shown to be conservacive chrough com -

parison of the analytical responses vich chose =easured during yf l'

cescin g The =easured response can be piping displace:entsj q

hd/or restraine forces [ The si.:plified mached requir.es that dynamic response of piping, at selected locations, be,:easured.

A mi n 4 "uN of cuo separate re=oce locacious selected for the data points should be based on the analysis perfor=ed.

In addition fluid pressure :ay be =easured. The necessary parameters to be =easured and their locations shall be included in the cesc specificacion.

(

l The criteria for acceptability of the =easured dacs is given in 5.2.3.

If the cricerion specified in 5.2.3 is not mee. additional evaluation of the piping syscams based on the =essured dacs shall be made to justify the acceptance.

This =ay include reanalysis of the piping system based on sessured dats.

O. %

?

\\

i 3.2.2 Instru=encacion i

e Appropriate inscruments as recommended in section 7.0 shall be utilized for obtaining the piping system responses.

5.2.3 Measurenents and crtcaria for Acceecance D

The measured responses shall be ecmpared to che analytically obtained a

response of the syste:2.

If the analysis indicacas larger responses chan chose measured and the general requirements of seccion 3.0 concerning analysis versus case condicions have been =ec ' chen che vibratory response of the syscc:n is acceptable.

~_

5.3 Inaccessible Pisine (3ech scendv-Scace and Transient)

For inaccessible piping systems requirt=g =enicori=g, che search procedure for =ax1=um response locacion is noc required. The i

locations of anticipaced saximum respcuse ac which =easure=ent devices are to be applied shall be defi=ed. Adequaca precaucions shall be caken'co verify chac che assu=pcions used for che seleccion of sucicipated =ax1=u:2 response locacicus are consistent vich in-sicu l

system response.

i l

i

.l

- ~~

e-

/

the port ton ief t ': - v : t"~2 I S" evaluated in V:7:-t, or when

.i s

6.0 RICORCUS '/ERIyIC.iTICN.T I!CD TOR STIADY-STA!!,wD TR.ws ty.:;7 'f:3g g;;o3 i

\\

The machod described in this seccion is required when &

.-the.necho.h of che ' sections 4.0 and 5.0 are not applicable or overly conservative.

It 'cs also 1:,.cended for applicacion to systems where che dynamic characteristics indicace that the syscam modes are primarily a result of rocking of massive equipment (such as pumps, heat exchangers, ecc.).

The pri=ary objec:1ve of this verification method is to obtain an accurate assessment of the vibracional stresses in :he piping system from the =easured vibracional behavior.

Two acceptable cachniques for i=ple=encing this =eched' are given in sections 6.1 and 6.2 along vich corresponding require =enes.

Secticu 6.1.is supple =enced b'y non=andacory appendixes 3 and C which describe several =achods of i=plemencing this technique.

6.1 Medal Resconse Technicue 6.1.1 Ceneral Reeuirseenes This = ached requires :hac :he =odal displace =ents and natural 1

frequencies of the syscas be idenctfied via the est daca.

l The teched also requires that a medal analysis of :he system be perfor:ed 71alding analytically dece - ' ed natural frequencies and mode shapes and odal scress vectors (or bending :o=enes) corresponding to :he =cde shape vectors. The analysis and :csc natural frequencies and nodeshaces of the piping system shall be i

cor clared and :he analytical seress vec: ors shall : hen be used :

determine the actual state of stress in the piping due to the measured modal displacceenca.

o

6.1.2 Test Recuirements The piping system shall be inscrumenced suf ficiently to enable identificacion of the natural frequencies and oodal displacements.

It is not neceseery to ensure chac the measurements are caken ac che locacion of maximum vibracien. The inscrumentacion say be capable of measuring acceleracica, displacemenc, or veiccity according to che guidelines of section 7.0.

Locations of inscru=enes shall correspond closely to points included in the analytical model of the system.

The system shall be axercised chrougn che condicions defined in case specificacions. A sufficient accune of daca shall be recorded, to allow aporopriate data processing as described in section 6.1.3.

6.i.3 Data Precessine Scandy-state vibracien daca shall be reduced to obtain che zero-to-peak displacement in each of the predcminant vibracional modes of the system. Several =echods of dece =ining the sodal displacemenca are available and evo of chase are discussed in che nonaandaccry appendix 3.

Aten using either of the evo =echeds described in appendix 3, special accencien should be given to separacely i

identify closely spaced : odes which =ay exisc in che system.

i 5 l.a Test / Analysts Correlacion l

The seasured =cdal frequencias and modal displacements of the Piping system shall be correlated to analycies11y obtained k

, +, - -

-w

.e-..

e-.

m

e r

modal frequencies and modeshapes for all major contributing moders.

As a minimum, the cast and analytical nodeshapes shall correlace with respect to the predominant sodal direction; the relative magnitudes of the modal componen s need not be in exact agree nne.

In additica, the corresponding modal frequencies of the :est and analysis shall be in reasonable agreement.

6.1.5 Evaluacion of the Measured Resconses 9

The seasured modal displace =ents of the piping and the correlated analytical resul:s shall be used :o 'obtain an accursce assessment of :he vibrational s esses (or nc=en:s) in the piping system.

A =ethod for obesining :he vibes:1ccal stress La che pipia; using the measured piping displace =ents and :he informacion from the modal analysis of the system is given La noc=sndaccry appendix C.

The resul:1ng vibracicnal stresses shall be evaluated according :o the accepeance cri:erts of see:1on 3.2.1.2.

i 6.2 Measured Stress Technicue St sin gages can be used :o directly deter =ine scresses in the piping systen during steady-state or ::ansienc vibration. This sec:ian euclines :he general requirements in :he use of strain gages.

Several precautions associated vi:h the use of strain gages are presented in see:1on 7.0.

These precaucions sheuld be considered prior :o defining :he :est program.

j-C1

6.2.1 General Recuirements The piping system shall be instru=anced on straight pipe with suf ficient number of gages near points where maximum scresses in the piping system are expected to occur. Strain gages shall be locacpd remote from poincs of stress concentracion.

6.2.2 Evaluation of the Measured Resconses The experimentally obtained strains ac che inscru=enced points in the piping system shall be converted to a 3-componenc momene see and evaluated using the acceptance cricaria of subseccion 3.2.1.2.

D h

[

B

/

7.0 I:iSTRU:E ITATIO:I A:iD :EASURE:C:iT TECH: IQUES Instrumentation and =easurement technique guidelines and n.

~ -....

suggestions are contained in non=andatory appendix A.

Note that this section is not intended to be all-inclusi*te and the

=ost up-to-date instru=entation and =easurement eachniques appropriate to the vibration a=plitudes and" frequencies of the piping system =ay be used.

All ins re.=entation shall be reviewed against the expected test environ =ent (pressure, te=perature, humidity, etc.) and against the expected range of system responses (frequency, displacement, velocity, etc.) to deter =ine its capability of funculoning as required.

The acceptance criteria in this Standard is based on zero to peak piping ' deflections, therefore the instru=entation used

=ust result In actual ~:ero to peak =easurements.

If the instru=entation used yields

=s =easurements, then conservative

=etheds must be used to convert the :.s =easurements to :ero to peak values.

Ca vs

_.. - - _ _ - - ~,

NMANDATORY APPCfDIZIS 3.0 CORRECT!'IE ACTIC:t APPEIDIX A Should the piping vibrat ICN AND MEASURagNT TICMTIQUES 3.2, further evaluacion l

necessary to make che s) include identificacion a secd in sec:1on 4.2 for escimating che amplitude foccing function, decuni oc esquired to yield precise resul:3.

Even so*

modific2 cions, addition tcioned against accanpcing :o use chese sinple ehanges in operacing PTC

co where erreneous escinaces v111 al=ose s urely condiciens.

plo, low-ampli ude (430 nils) vibrations at acise (M.0 2:) would be difficul:

Experi$nce has -shown tha

o quancify

n10.

I.ikewise, lov. frequency (43 Hz) vibra:1 is obtained by supporcin:

ons

o road with an.. optical vedge because che eye' nasses and piping discon:

s s inadcquace to yield a distinct incersec:fon bypass, and inscrument p:

the regions of the vedge.

nasses (valves, flanges, relative vibracions.

t.tlifvt:.e pising sy,ee-ts ("MC 21 After :cereceive accion i scussions regarding hardware selection 3

. are also applicable :o :he Risor:us reduced :o satisfy che ac 1).

If car active restraines nake the piping system ac:

shall be reviewed and rev-easure=enes 13 :3e piggegy,g 7;

vancages include a car 35111:7 for hiz**

~

9 l

e

_N

t 1

temperature operation, physical durabili:7 and reliability, ease and stability of ' calibration, Laceinsic low noise, linearity over i

i a vide dynamic range, small sass, and ease of application for absolute measurement.

Of the evo types of pia:celec:ric accelerome:ers in vide use, shear-mode acceleromecers vith high sensitivi:1es ( 10 PC/g) are the preferred type for low-frequency measurements (~oolov 3 E:),

because compression-mode accelerometers cand to produce spurious outputs (from case deformation and ther=al shock) ac low frequencies. Accelerometers that have : heir signal return lead electrically isolated from the metal case facili: ace control of unwanted ground loops, but are considerably sore expensive than the grounded case variety. 0ther machods for controlli=g ground loops are created in sec:1on A.2.1.3.7.

Accelerometer characteristics of particular tsporrance for piping measurements are:

Variation of sensitivity vich :e:perature.

If :he change a.

in sensitivi:y from room :amperature :o operating :amperature exceeds 100, a correc:1on fac:ce decarmined from :he =anu-facturer's data sheet should be applied.

b.

Variation of sensi:ivity vich f:ecdency. This variacion depends on the type of acceleremeter, :he soun:ing technique used, and whether 1:s out;uc signal ia fed into a char;e-sensi:1ve amplifier or x voltage-s,ansitive amplifiar.

Varia:1on of senst:ivi:7 may be as high as ;~ per dec:de in

NCNMANDATORY APPDDIXES APPDDIX A INSTRUMCCATICU AND MEASURDENT TICHNIQUES A.1 Visual Inseeccion Method (7MC 31 The s1=ple aids suggested in seccion 4.2 for estimating the amplicude of displacement ara not required to yield precise results. Even so, the user should be caucioned against acca=pcing to use chese simple e

aids under circumstances where erroneous esti= aces vill al=osc surely be obtained. For example, lev-amplicude (430 mils) vibractens ac relaci"ely high frequencies (MO H:) would be difficult to quancify vich a spring hanger scale. I.ikewise, lev-frequency (45 Hz) vibraciens are usually difficult to read with as..cpcical vedge because che eye's persistence of vision is inadequace-to yield a distisc: intersection between the dark and light regi=ns of the vedge.

A.2 Simolified Meched for cualif rine ?icine Systems (VMG 2)

Many of che folle ring discussiens regarding hardware selection and =echodology for VMG 2 are also applicable co che Riger us Verificacion Meched (VMC 1).

A.O.1 Mardware A.2.1.1 Sensor i

One sensor for VMG 2 =essurements is che pia:: electric acceleremecer.

Its advancages i=clude a capacility for high C3

9 frequency. If the varia: ion in sensi ivity exceeds 10~ over the frequency band being =easured, data should be corrected in accordance with the manufac:urer's data sheet.

Maxt=um temperscure of operacion. Under no circumstances c.

should :he maxi =um operacing :emperature specified *oy the manufac:urer be exceeded. Eevever, direc: acrach=ent to the pipe surface is usually feasible because acceler: meters vi:h maximum, temperature ratings of at least 650' F (345* C) are readil available.

f Thermally insulated sounts =ay also be used, if necessary, to reduce ihe temperature at the acceleromecer.

d.

High-frequency resonances.

In addition :s the relatively small variation of accelerometar senai:ivity : hat =ay occur over :he device's working frequency haad (itas b above), al=ost all acceleromecers exhibit greatly increased respenses in a range of higher frequencies (usuall'/ 5 kHz or greacer) where the

(

acceleromecer internals resonate. To che ex:ent possible this frequency region should be avoided, since response correction 1

fac: ors vill be large and i= precisely knevn.

A.2.1.1 Cables Low-noise flexible coaxial cable is strongly recr== ended for use between the accele::=e:er and :he signal condi:ioner (or l

remote preamplifier, if one is required).

Such esole is available for cencinuous operation of 3C0* T (250* C).

A few :ypes may be used for short ti=es se higher :e:peratures, and sc=e exposed-besid Osble can be used centinuously se bl.;her :ascers:ures.

1 37

p._...--

Hardline (non-flexible), mineral-insulacdd cable is not reco= ended for camporary installation of sensors because of. its high cost, j

susceptibility to fatigue is11ure, and difficulcy in installation.

~

If possible. the cable should be continuous (connec:1onless)~

from :he sensor to :he signal condi:icning uni:. I! connec: ors must be used, then precaucions should be :aken to avo:.d :he introduccion of moisture ac chase locacions, since both system 3

sensi:1vi:7 and reliabill:y may be adversely affected.

100fbifmh l

In general, icng cable runs ( :P becueen the sensor and :he signal condi:1oni=g unic will produce high noise pickup or signal-at:uuation, and a remoca preaeplifier (or remoca charge converter) vill be required :o avoid chase difficul:1es. Consul: che accalaro-meter and cable sanufacturers' dans sheets fos loca11s. The i

i connection between the remece charge conver:er and :he signal condi:1cner may be made with inexpensive coa:cial cable or v1:h a shielded cvis ed pair cable.

A.2.1.3 Si2nal Canditioner Ei A.2.1.3.1 C.w.ersi tecni.ne ::s c

')

A signal condi:icner vi:h a charge cenvertar inpuc (ce=enly

'L l

called a charge amplifier) is rece= ended because :he accelero-

, J...

mecer sensi:1v1:7 does not vary vi h cable length when used in

.w the char;e mode, whereas acceleremecer sensi:1vi:7 varies vi:h 4

' cable leng:h unen 1: is connec:ad :o a vol: age-sensitive amplifier.

33 y

--w,.

.m-,

w

.m.

_.m, w

.-y- +,.

3

..-..,m.

Integracing circuits yiciding velocity and dispiscoment eucptt:

\\.

from the acceleracion signal must be included in the signal

_ condicioner.

Cain normalizacion for direcc-incorporst' on ol' t ~

~

accelerometer sensitivity (as supplied by the manufsecurer) is an important feature because all outputs can then be dest 4nud to read out directly in absolute velocity and displacement units This gain normalizacion would typically be required co accommodste accelerometers with sensitivities ranging frem-10 to 250 pc/g.

A.2.1.3.2 Frecuenev'Rsnee A working range frem 1 to 1000 F.z vill cover practically. all piping applicacions.

A.2.1.3.3

'libracion Scale Rante The. signal condicioner should typically be able to measure velocities over the range 10-2 cs 10~ in./sec :=s, and displace-

~

ments from 10 ca 10 in. ras.

It should be realized chse chese measurement ranges are necessarily frequency dependanc, i.e.,

due to physical li=ications of background noise and Lnstrumenta-tion noisa, che lowest levels of vibration cannot be =casured reliably ac the low end of the frequency band and, conversely, che highesc =easurement ranges vould cepresene unrealiscically high accelerscious se che high end of the frequency band.

For further guidanca, see seccion A.2.3.

To provide accursta measurements over che wide impli:ude range:

1 soecified above, che signal condicioner may provcde ;everal fixed-gsin adjusc=ents or tacernedisce full-scale ::Ince:i.

o A.2.1.3.4 High-Pass Fil:erine Ac least two switch-selected low-frequency cutof f lisi:3 (typically 0.3 and 3 H:) should be provided :o el1=inate ex:re ely low-frequency signals and unwanted noise. The fil:er complexi:7 should be ac lease :vo-pole (12 d3/cc:ive) for velcci:7 signals and ac lease :hree-pole (18 d3/oc: ave) for displaceaene signals.

A.2.1.3.5 Low-Pass Fil:ering Low-pass f11 caring of ac least two-pole complex 1:7 should be applied ac the upper end of :he vibra:1on band :o eliminace unwanted high-frequency noise. The eucoff frequency is noc critical, but would cypically bee =1000 H:.

(Noce:

'Je say vanc to supply frequency response accuracy (say +J d5) specifications for A.2.1.3.4 and A.2.1.3.3, is addition to the approximace -3 d3 cutoff frequencies. }

A.2.1.3.6 3and-?sss 7ticering Further filtering of :he veloci:7 and displacement signals say of ten be desirable :o reduce incerf arence a=cng closely spaced frequency ccmponents, to enhance :he signal-cc-noise racio, i

and to help isolate vibracion =edes.

To these ends, a svi:ch should be available to provide ei:her vide-band (lisi:ad only by the set:ings selected under A.2.1.3.4 and A.2.1.3.5) or narrew-band signals.

For :he lac:ar, :he band cencer frequency should be continucusly adjustable fr:s :ne fr:nc panel over :hree, one-decade ranges f:cm i :o 1000 3:.

A ecc =nended bandwid:h

$24

between -3 dB response frequencias is 10-20.7 of the en:e frequency, i.e., a "Q" beeveen 5 and 10.

The c:mplexi:7 og :he filter should be at leas cuo-pole (12 d3/occave). Calibested front-panel indicacion of center frequency is desirable.

An alternacive mached for achieving the same egds is :s employ a spec: rum analyzer.

A.2.1,3.7 Control of Ground tooos The signal conditioner should have a frent-panel svi::5 that provides separation of th.e signal references for the inpue circui:s and the output circuits. This allows an internal differencial circuit to remove common-mode gr:und vol: ages caused by having the transducer case grounded at the point of sensuremenc. The

~

switch and differencial anplifier prevenc large ground-circuit currents from flcwing through the acceleremecer cable shield, and thus help to minimize che appearance of line-frequency conponents at the output terminals of the signal condi:icner.

A.2.1.4 Outrue Si2nsis and Readou:

The AC outputs for veloci:7 and displacement should have a conven-ient, round-number vol:sge associated vi:h full-scs'e output (e. g., 1.0 V ras). These outputs are for viewing the Jtenal wave-forms with an optional oscillosecpe. Peak oucput capabtit:y of 110 V st 10 nA vith 50-ohm output i=pedance is sufficient.

A. 2.1.1.- l Visual Indiestion In addition :o in oscillascope, a sui: soly danced.inalas.

7e t t r is stronsiy rece:. '. ended :o indi:sta che : rue ou value M

'"'th 41

+

displace =ene and veloci:7 Cue. :o the typical ti=c-varying amplitude of the signals being =enitored. digital indicatoes are generally unsatisfactory for quantifylng vtbencien signata.

5 Furthermore, a crue r=s indicacion (rather :han an average or peak value) is preferred because vibracicn signals :ypically i.

encountered =ay be al=ose randem i= charac:ar vi:h near-gauss!an ampli:ude distributions, or quasi-periodic wit.' sinus-cidal amplitude distribucions. or pulse-lika vich high cres:

factora, and someti=es =1xtures of all :hree.

If r=s censure =ents a're obtained, the require =ents of sec: ion 7.0 ara :o be used.

-a A.2.1.4.2 Averseing Averaging the output of :he crue r=s circui: / is requirac to achieve a stable =eter indicacio'n.

S.e low pass cucoff frequency y

required is related to the =in1=um seasure=ene frequency selected by the user's choica of high-para fil:ar is sec:1on

t..

A.2.1.3.4 If :vo-pole low-pass fil:ering of the ::ue r=s

.,.s outpuc is used to achieve :his averagin'g, a cutoff frequency of no more than 1/2 :he =ini=um frequency of =easure=en: is

,r recot=nended.

This choice vill yield a peak-co-peak ripple no 1

ash greater than 6". of the indicated :=s value for sine waves through-out the measuremenc bandwid:h selected. The sec: ling ci=a for e

such a fil:c is approximacely 1/f seconds, vners f is the i

j g

lovesc = essure =ent frequency, expressed in R:

1 A.2.1.5 Auxiliarr Icui = enc An oscilloscope for viewing the wavefe:..3 of :he 'rel city and l

displace =ent outputs f:Om the signal conditioner'is opcional buc I

/ A Q%

4 quite helpful under e.any circumacances. A real-time frequency i

analyzer (fer modal separscion) and an analog nt tape recorder (for data preservacion and/or additional off-line study and processing) are also useful, but opcional, equipment. The aversged outputs from the true rss.circui:rf described in see:1on A.2. L.I. 2 sight also te made available to an optional strip char: recorder,

~~

thereby provid1ng a permanent record of :he analog me:ce indication.

A.2.2 Alternatives A.2.2.1 Accelerometer I.imitacions All transducers have limi:ations and some al:ernative sensors uay give superior perfornance under car:ain circumscances. Two intrinsic shortcomings of pia:celectric accelerometers chat saf

ause difficulties in plane piping applications are (1) low-level, his.t-imoedance outpuc._ and (2) poor signal-co-noise (S/N) ratio at low frequencies., particularly follewing :he double integration required to obtain displacement.

I f

In all but the :ost severe elec:rt:21 interference anvironments, the acceleremeter's low-level output can nevertheless be made to yield an accepesbly high S/N ratio by placing a preamplifier (vi:h or without charge converter) close :s :he sensor and by using one of the rec:= mended icw-noise esble tfpes described in sec:lon A.2.1.2.

Should these measures fail. :he user =ay be able to schieve bec:er perfor=ance with :he high-cucpuc, lev-i=cedsnce devices describe d in sections A.2.3.2 and A.2.3.3.

.w 63-

o Dif ficulties in inferring displace =enes at -low frequencies fr:m i

accelerometer signals of:en arise because :he sensor responds inherently to acceleration, not velocity or displacement.

""h e latter required ou:pues must therefore be derived by single-J

" and double-intes: scions vi:h respec:. co cine, and these operations produce a magnification of any icv-frequency ex::aneous noise chat say be present. This difficui:7 can be overcome by employing alternative sensing devices that :espond inherencly to velocity and displacement, as follows.

A.2.2.2 Velceity Sensors Veloc1=sters (or " velocity pickups") are sensors designed :o respond to this sariable directly. They usually consist of a moving coil or =oving sagnac arranged so : hat the elec::ical output generated is proportional to the rata ac which the sagnecie field lines are cut by the moving element, and hence 1:s velocity. The main advantage of these electrodynamie ::ansducers over piezoelec:P.c accelero=eters is that: high-level, low-impedance ou:pu, thereby saking their sigt.ls relatively 'me :o elec::c=agnetic noise pickup. Their chief disadvantages are : heir larger size and their somevnac :escricted useful liaar bandwid:h. Like ac.alerc=e:ers, they suffer fr m resonant responses at high frequencies and Untamina ion f::s backg cund at lov frequencies. The lac:er shortcoming limits their usefulness in providing displacement indications at lov frequencies, since :he necessary in:eg ::ica

ends to a=plify low-frecuency noise selec:ively, i

t i

/<

c t

..,.__,r.

i 1

A.2.2.3 31sslacement Sensors Types of direct sensing displace = enc _cransducers applicable to piping vibration measurements are c.ie eddy cur 5end2'ensor (or s

" proximity probe"), che linearly-variable differencial transformer (L7DT). andethe lanyard gage potenciemeter. All s. case absolute displacemenc relative to a fixed reference, and therefore have frequency response and Shi curres that are unifor:c all :he way to zero frequency (DC). This is chair chief advantage, along with high

• electrical eucput and hence i== unity to extraneous noise.

An accendant disadvantage, hewever, is chac chey must be mounced firmly to some structure chac is stationary felative to che vibracing system whose displacement is to be measured, and this is of ten difficult to acccmplish in au cperating planc

~~

environmene. Other disadvantages of chase sensors are (1) generally poor high-frequency response, (2) li=1ced range of displacemene ever which the transducer reapends linearly and vichout hysteresis, (3) need for special accenpanying electronics r-.

(oscillator /de=odulaccr) and cabling, and (4) in some cases.

high noise, offsec errors, and linited (quanc1:ed) displacement

[ ;.,.--

casolution.

s.

A.2.2.4 Soecial Sicuaciens M. ore exacic instru=encacion (e.g., laser vibremecers that de:ccc e%..',,

che Doppler shif t accenpanying socion of :he :argec) is cc::ercially i

]-

availab.'e for chose special situacions requiring unusually high

=easurement accuracy Or whare pnysical access :c the l'.br1c ht4 structure prohibica use of the sensors ~alreacy den :r.b d, but men devices are c:o speciali:cd to warranc further cu.r:pe L'n in

hia occu=ent.

ani I.

A.3 R12erous Method for Cualif ring ? icing Svste=s P.'".C 1)

In addi:1on :o :he instrumentacion discussed for VMC 1 the following instrumentation is applicable to VMG 1.

A.3.1 Strain Caces Method The method of strain gages is a method of measurement of strain (din /in) at selected points in the piping system which can, in turn, be related to stress. Test inscrumentacion sys:em :ypically consists of three major items: Electrical strain gages, signal cenditioning, and data recording systems. The cype of gages normally used on the piping sys:eme are sicher the weldable or the bondable type.

Evaluation of the temperature and radiation level will limit the use of bondable gages. Weldable gages are available which will.operace for t.11 temperature and radiacion levels typical of nuclear power plant piping systems. The usual requirement is that the scace of stress at points on :he piping 4

system can be decernined from strain-gage readings. This implies the use of an appropriate :heory rela:1=g strains to stresses.

The validity. of the final resul:s depends upon the validity of any relationships used in reducing the daca.

A.3.1.1' ?roblems Encouncared in :he Use of Resisesnee Strain Caces The user of strain gages =ust be aware of some problems encountered by :he use of these devices.

So=e of chese problems are:

.--w--.

-w"'----"'9

--- -- (.i

o (a) Teenersture Ceccensation: If strain gages Ve:c to be used for a long period of time, temperature =sy vary over a long

~~~

' period of ~ci:ne; ic is 'excremely i=portant that temperature

~

ccmpensation be as perfec: as possible.

If camperature compensacion is i=per8ec:, : hen readings interpreced as varying strain may only represent a variacion in temperscure.

Dua to :his variacion in ce=perature, the strain gages are not recommended for scacie piping stress measurements.

c (b) Bond Stabili:*7: Any shrinkage, swelling, or creep of the bond or any change in :he conductivi:y of the bond nay produce a signal which is unrecogni:ed from che strain-gage signal. Adequate cu-ing of strain-gage bond for long-te=n casts is i=portan:.

(c) Instrueent Stabili:r: Many fac:ces acting on the scrain- ~

gage circuit and signal device may ;eoduce signal $ that are unrelated :o strain. Chac.k for resistance, supply

~

" E- -

~'

voltage variacion, and to correc: for any drif: La che

-(

1 indicators prior to scar: of :he :ssc.

(d) Moisturecreofinz Strain Caree: Moisture ac:s to reduce the gage-to-surface resistance or parcially :s short circui: :he leads or see:1ons of the gage i:self.

This may produce a change in resistance.which is equivalenc :o strain, i

l 1

Moistureproofing 12 necessary for indoor and cuedcor testing.

l l

Some moistureproofing :achniques are: Caring the bond, insulacing, or use =oistureproofing agenes, or cover :he entire asse=bly with Epexyli:e or c:= par:ble raccr'.al.

l

.. # ~~~

A.3.1.2 Serain Cares Sub?ected to Nuclear Radiacion The use of bonded resistance serain gages in radiacion environ-ments is a suspect. Any organic sacerial (most strain-gage bonds) are affected by nodest a=ounts of radiacion; the radiacion produces di=ensional changes as well as change in :he nachanical and electrical properties. Short-c1=a tests can be made durin6 irradiacion until gage-co-specinen resistance breakdowns. Scma semiconductor devices are affected by radiacion damage; however, silicon semicondue:ce gases vill :olerata radiacion flux of ac__ _,_

lease 10*' particles /cm2 1

with eneigies greater :han 1 Mav before

~~

changes in resistance of gage fac:or occur. Special at:encien should be paid :o soldered strain gages joints and lead vires, since they are also affected by radiacion. 'Jelded connections are recommended.

A.3.1.3 Strain Measurements at With *enceratures Many cachniques are available to use serain gages at lov or high (9972) g (leSo%)

camperature (350* ? 1200* F). Meca11ergical changes chac preduce sudden and/or irreversible resistance changes are not enceuntered ac cenperacures below 350* Ff(I"!7 'c).

o-Strain-gage _anufactural y

reemndacions are to be followed when using sersin gages above 350* F[877 d).

~

A.3.1.4 Data ?recessine Sceady-scace and ::ansient vibraci'en data of piping syseens should (y cm/cs) be reduced to obtain =axinu= sersin (din /in)dat points shore cu

-n.-

max 1=us stresses are predic:ed by analysis due to vibracion.

4 Evaluacion of data shall be made where the material.on which the

\\

gages are mounced behaves in accordance with the linear theory of elastici:y throughout the range of strain be'ing investigsted.

Evaluacion df scre;,es from measured strains beyond the elastic limir. is uncertain due to the lack of practical =eched for relating stresses to strains in this region. During data processing, attention must be paid to " gage factor" value for uniaxial sciess field.

e e e

e a,

w.

l l

i

(

l i

~

~

.u

. w.

s p

NCNMANDATORY AP?CIDI7. 3

.c -

This appendix describes two methods of obtaining modal displacements of imv ~

7. g

che piping system from the measured total displace =en: time history. It s

4.

is reconnended to be used in conjune: ion with mandacot/ section 6.1

, p. 4 - -

9

~,,-

3-1 Fourier Transform.Meched' g

.. -;g:

The recorded acceleracion, veloci:y, or displace =ent ti=e histories can be j

converted to a spectral density func:ica using Tasc Tourier Transform s4 a

7,,

techniques. The spectral densi:7 should be co=pu:ed in the frequenc1 range which contains the expected predominan system essponse. A sufficient e'I

~

number of spectral averages shculd be made :o ensure cha: :he densi:7 function m

has converged.

Incegration of the density function over discrece frequency bands arcued :he predominant modal responses yields :he EfS nodal response.

These can readily be converted to peak-cn,,eek response through consideracion of the scanistical proper:1es of the respense.

,t..

,. J... -

~s -e In addi:1on to he modal responses, :he spec ral densi:7 func:1cn vill

.ee.

6 indicate system response at determiniscic frequencies associacad vi:h shaf:

s.

w

,9 ~

and blade passing frequencies of rotating equi;=en: which feed :he piping

. e

==.'

system.

l O

+ _,..

W.

The piping displace =enca ac :hese frequencies shculd be deter =ined.

3.h,.

he j

., ?.

Piping displacemen:3 at these frequencies should be absolutely su==ed ut:h

,C+

the medal displace =ent of the piping system sede which is nearest :o the

, fe'

• M%.

date:.-inistic frequency or which closely rese=bles :he displaced con-

.T.,.

QI.,

figuration at :he decer inistic frequency.

j- **.t:

• T De user of :his method is refer ed :o the lacesc envision of.dSI 5:10 t!.

J.

en:icled " Methods for Analysis and presen:stien of Shock and Vibra:ica e t' 3

t.2.-:.

"4 C 3..

7f f.

L

e ag-

..e u t..

?.'.~.

to.

B-2 Other Methods og

~

..,.w

-jj.

Alternative machods may be employed, such as modal superposition, provided e

/-

d.r..'=m s 4 J vd, 5 :-

,,-. 7 chat the machod used is cu -nacroly conservative and. the cast analysis.

8

, M ? ---

correlacion requirements of section 6.1./. are met.

~

9 ee 6

, e..r. a

-. - - ~

....... ~. ~

g * * =.

"de e*

1 f

i amr e * *

, e es..

f.

.1 s.

O.

ee.

.e p

.e e M.w*

e e.

• ano em..

.. g 6.<*,

, y e.t ?

'e

• er w.

e,n=,

• Y

/*

h.t -

.?.( > =2'*

w,

a*

e.

e,4h*,

0 hBD g

g eq.

r e

• 13 r %,

1. e e

enr,

S 98 a *.]r

=,%

a

. p ew.

p.'.e..O s*.

-.'1

..s.,

N)

. /I.*i."

.e en9 e.

W

.C'.,

.*6 e

O*

e*

• J.

M..,p*

..~ :.

E

.4 v.

7/

. =. -

,_,y

s e

t NONMANDATCRY APPENDIX C j

This appendix presents a method for converting measured modal displace-ments of the piping tystem to bending stress (or bending moments) through utilization of analytically cheained modal characteristics.

Ic is recommended to be used in conjunction with mandacory section 6.1.

C-L Test / Analysis Correlacien The modal displacements, at each measurement point, obtained in section 6.1.3 should be cabulated,and norma 11ced to an appropriate value (such as the

.l -

~

~N maximum displacement) in c..-;. mode.

"he relacire sign of each displacemen:

- r'~a e

can be obtained by computing the phase between measuremenc points using 4

Tourier Transform cachniques. This yields' a normalized modeshape and modal',

4.

frequency obtained by cast chac can.be comoared to analytically obtained * '

^~

normuliced modeshapes and frequencies. The case and analytical results.

m..

a 'W'. "? -

p ).

~

W..*;*

7..,

should be correlated according to che mandatory requirements of sect w,.

' it * '

a u q:.G

'y r

~} d 4-2 Evaluacion of :he Measured Reseenses

.c"..

.6,, ap

'b..

y

_4 Having achieved a correlacion of case / analysis results, che analytically

.m obtained modal moments or stresses in the system piping can be de'cermined using the actual modal responses obtained trem the cast daca.

This can

'be done in the following way.

The measured modal displacemene ac poinc j in mode 1 (denoted by 0

)L divided by the corresponding analycidal displacement (D^

), yielding the modal respcuse factor K,,,

l 72

-r. -...

.,,-...__,,,.-.___,__..,_-.-g,.

...m

hf '&

.cx

.ti ;.

s.

D 11 i.e.,

K

=

i A

.~o 5

D

.u -

ij v. * 'O,

.. ~.

b

• 'f Theorecically, all K ) vichin a mode should be che same~ if perfect correlacion g

b of cost and analycical mode shapes has been achieved.

Realistically, however,

~.,

che K will vary. Therefore, for each moda che maximum K is chosen as che 9,v -

Lj ij 1

. 4...

modal response f actor for acde 1 (denace as K.).

The maximum K should be

.s-t x

ij chosen from among chose K

. M.

gd in the direccion of pradem ant modal motion, i

c,

'l..

e, V *,_

co reduce unnecesspry conservacisms. Having obesined the modal response r-

-7 factors-(K ) for each mode, che case stress veccer (S'd) for each mode

-p -

. M.

• should be calculated by premultiplying che analytical seress vector * (S*\\ )

. m.:

0 e

by the modt.1 response factor.

i.e..

(S J)i L (S*'j)L

=K

-A;

.$?%

, }' g,.

The modal stress vectors chus obcained should be combined by an appropriate

, { " ~.."

conservative machod to obesin the cocal stress in the piping.

, '.'.1; i.'em y

.J.

I

~* ) #,

w 2--

9.-

A;,-

. ~,..

. f.. +

[

• It is assumed inthismethodchacthestressvectorinc'ludesch)eseress indices as defined in subseccien 3.2.1.2.

Alternatively, che modal bending soments in the piping (obtained from the odaL analysis of the piping) can be converted to stress using the equation for 5 defined in subseccion 3.2.1.2.

'U e-W,.

.N '

.t-

....-l+.

g S

y-e

,f NCWXfDATORY APPE' DI% 3 Mfs

.se-This appendix describes a method for establishing a velocity criterion' for scree:1s; piping systems. Using chose procedures, piping systems requiring furcher analysis can be determined. This appendix is to be used in conjunction with seccion 5.1,2.4.

D-1 velocity Cricerion The expression for allowable peak velocity from 5.1.2.4 is

,i O'3 (0.8 S,y)

,,,(

CC 3.64 x gg

,ll C

C 5' a

3 2*

C = Correccion factor chac compensaces for che effect of concenersced t

weights. If concentraced weight is less chan 20 times the weighe

. Id >

of the span for straight beams, L bends, U bends, and Z b ends, m

,. ar.

l' a conservative value of 0.12 can be used for screening purposes.

-7,

1. de w

3 v.

w. + -

y..

C4 = Correccion factor for and condicians diffarent frca fixed endr s.1

.e. ;

z l0. - -

s 'k31 g}Ia

• e and for configuraciens different f:=m straight spans.

A s.

. ;.v:

As examples:

~~e-(.A C; = 1.33 for canc11ever and s1= ply supported beam J"

C = 0.74 for equal leg Z bend 4

C; = 0.33 for equal les U bend 4 = 0.7 as conservative valde for screening purposes.

C C3 = A correccion factor accounting for pipe cencents and insulacion.

~

j Tor concents and insulacion equal co che weight of the pipe, the value would be 1.414.

In nose esses it is less chan 1.5.

CX = Scress indices as defined in 331. 7. Appendix 0. Isble 0-201.

g2 C X,f I. for nost piping syster.s.

7 9

7f t

t e

D-2 Screeninc '.'e locity Cricarten

.; A.

If conservative values of the correccion factors are c.ombined, a criterion

. 'can be derived which should indicace safe levels of vibracion for any type of piping configuration. Using this criterion, piping systems can 'be checked

' sad chose with vibracion velocity levels' '1' ver chan the screening value vould o

cequire no further analysis.

Piping' systems chac have vibration velocity levels higher than the screening value do not necessarily have excessive seresses, but further analysis is necessar7 to establish its acceptability.

W The following correcticn factors are censidered to be conservacive values

\\

and should be applicable to mosc piping ccafiguraciens; however, che

'w.

aA conservatism for extre=ely ecmplex piping configuraciens cannoc be accescad.,

.e E "'D C

0. 12

=

t

-n.

C,K, 4

3

.y m

5..

=

'El '" '

.J. -

., m -<q.L ~. -.~

C 1.5

=

3

.,;,W. C :li,.

C 0.7

.. a

=

NDlO !*'

s. -

k

• '.L-, ~ E. F.

0.3 S g

al 10,000 psi

,j

=

(0.12)(0.7)(.00364)(10000) yall. -

(1.5) (4)

V,

= 0.5 in/sec Screenine vibracten velocity value.

D-3

_Use of Screentar Vibrtcien Velocic r 7alue A screening vibracion velocity value of 0.3 ips has been established which can be used in conjunecion with 5.1.2.4 Piping systems with peak velocities less chan 0.5 ips are ecnsidered to be safe frem a dynamic stress standpoint and require no further analysia.

If vibracional velocities grescer chan 0.3 ips are nessured, 'chen further analyses ar e

required ca determine accepcability.

76

O e

o e

The fits: s:ap :s :ska if ribrzeien ieloci:ias are ;;es:er than 0.5 ips a

is to deter =ine nors accurate talues of the cor;ection facects C, C), and C and the s::ess indices C K so tha: the applicable veloci:7 cri:eria for 4

22 the pip'ing system in question can be established.

l O

e O

9 O

r r

1

(

t 1

4 l

e 1

,0 I

f I

e l

i e

e e

G

'74