Mechanical Questionaire

7/26/2019 Mechanical Questionaire

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QUALITY TEST EXAMINATION FOR MECHANICALPrepared by

Examinee No………………………………. Date: …………………

Name:………………………………………. BI-No. …………………

Discipline: ………………………………….

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What is schedule Q !ns"er : #chedule Q is an attachment to the contract$"hich is pro%ision o& Quality !ssurance and control$ Inspection and 'est Plan.

What is ()I *(e+uest &or inspection, !ns"er : ()I "ill be raised "hen the status o& preliminary inspection is satis&actory and items are

/D or WI'NE## PIN'.

What is N0( * Non 0on&ormance (eport,!ns"er : We need to issue N0( "hen the items 1 materials or system is not in accordance tospeci&ications and appro%ed dra"in2s .to a%oid recurrence.

What is an Inspection 'est Plan *I'P,!ns"er : ! mandatory item in the +uality plan that 2uides and assures +uality in a speci&ic type o&"or3 in a speci&ic se+uence o& Qc acti%ity steps.

What is a +uality control procedure* Q0P,!ns"er :! document that details the speci&ic steps needed to &ul&ill the Q0 acti%ity in I.'.P.

What are the %arious le%els o& inspection Explain /e%el o& inspection &or 4aterials:

a, /e%el 5 - Document re+uirements only no inspection .b, /e%el 6 - Inspection prior to shippin2.c, /e%el 7 - 4inimum re+uirements pre inspection meetin2 one or more unspeci&ied in

pro2ress sur%eillance %isits.d, /e%el 8 - #ame as le%el 7 exept that in pro2ress sur%eillance inspections shall be in

re2ular basis.e, /e%el 9 - (esident inspector continuosly monitorin2 the "or3 .

/e%el o& Inspection &or 0onstruction phase:a, /D PIN'# - the inspection acti%ity "ill not proceed "ithout the presence o& P.4.'.

representati%e.b, WI'NE## PIN' - the inspection acti%ity can proceed a&ter issuin2 the ()Ic, (EIEW - %eri&ication o& documents on its correctness.d, #;(EI//!N0E - inspection is &ree to conduct random inspection.



What are the di&&erent sections o& !#4E code Where these sections are re&erred

!ns"er: !. !#4E section I - (ules &or construction o& po"er boiler . B. !#4E #ection II - 4aterials. Part ! < )errous materials. Part B < Non-)errous materials. Part 0 < #peci&ication &or electrodes = &iller "ire. Part D < Properties. 0. !#4E #ection I - (ules &or construction o& eatin2 Boiler. D. !#4E #ection - Non- destructi%e Examination. E. !#4E #ection I - (ecommended rules &or care = operation o& heatin2 boiler. ). !#4E #ection II - (ecommended 2uidelines &or care o& po"er boiler. . !#4E #ection III - (ules &or construction o& pressure %essels. *Di%ision I = II, I. !#4E #ection I> - Weldin2 = Bra?in2 +uali&ication.

What is the di&&erent !#4E 86 code &or pressure pipin2

!ns"er:a., !#4E B86.6 - Po"er pipin2.b., !#4E B86.7 - )uel @as Pipin2c., !#4E B86.8 - Process pipin2.d., !#4E B86.9 - Pipeline 'ransportation system &or li+uid hydrocarbon = other li+uide., !#4E B86.A - (e&ri2eration Pipin2&., !#4E B86. - @as transmission = distribution pipin2 system2., !#4E B86.C - Buildin2 ser%ices pipin2h., !#4E B86.66 - #lurry transportation pipin2 system

o" can &lan2es be classi&ied based on Pipe !ttachment

!ns"er: )lan2es can be classi&ied based on pipe attachment as #lip < on: 'he #lip-on type &lan2es are attached by "eldin2 inside as "ell as outside. 'hese &lan2es are o& &or2ed construction. #oc3et Weld:'he #oc3et Weld &lan2es are "elded on one side only. 'hese are used &or small bore lines only. #cre"ed :'he #cre"ed-on &lan2es are used on pipe lines "here "eldin2 cannot be carried out. /ap oint: 'he /ap oint &lan2es are used "ith stub ends. 'he stub ends are "elded "ith pipes = &lan2es are 3ept loose o%er the same. Weldin2 Nec3 :'he Weldin2 nec3 &lan2es are attached by butt "eldin2 to the pipe. 'hese are used mainly &or critical ser%ices "here the "eld oints need radio2raphic inspection.

Blind :'he Blind &lan2es are used to close the ends "hich need to be reopened. (educin2 :'he reducin2 &lan2es are used to connect bet"een lar2er and smaller si?es "ithout usin2 a reducer. In case o& reducin2 &lan2es$ the thic3ness o& &lan2e should be that o& the hi2her diameter. Inte2ral: Inte2ral &lan2es are those$ "hich are cast alon2 "ith the pipin2 component or e+uipment.



o" can &lan2es be classi&ied based on &acin2

!ns"er: - )lan2es are classi&ied based on &acin2 as !. )lat &ace. *)), B. (aised &ace. *(1), 0. 'on2ue and 2roo%e. *'1@, D. 4ale and &emale. *41), E. (in2 type oint. *(',

o" the @as3ets are classi&ied based on the type o& construction

!ns"er: Based on the type o& construction$ 2as3ets are classi&ied as: - !. )ull &ace. B. #piral "ound metallic. 0. (in2 type. D. 4etal ac3eted. E. Inside bolt circle.

o" the pipe &ittin2s are classi&ied based on end connections

!ns"er: -Pipe &ittin2s are classi&ied based on end connection as !. #oc3et "eld &ittin2s. B. #cre"ed end &ittin2s. 0. Be%eled end or Butt "eld &ittin2s. D. #pi2ot soc3et &ittin2s. E. Buttress end &ittin2s.

What is Pipe

!ns"er: Pipe is a pressure ti2ht cylinder use to con%ey li+uids or transmit pressure &rom oneplace to another.

What is the di&&erence bet"een Pipe and 'ube

!ns"er:a, Pipe is identi&ied by NB and thic3ness is de&ined by #cheduleb, 'ube is identi&ied by D

= its thic3ness as BW@ *Brimin2ham "ire 2au2e or 61655 inch,.

'hree types o& pipe connectiona, 'hreaded

b, #oc3et Weldedc, Butt Welded

)rom "hich si?e on"ards NB o& pipe is e+ual to D o& Pipe !ns"er:)rom the si?e 69F and on"ards NB G D o& pipe.



Normally "here do "e use the &ollo"in2a, Eccentric reducers.b, 0oncentric reducers.

!ns"er:a, Eccentric reducers G Pump suction to a%oid 0a%itation$ 'o maintain ele%ation *BP, in

rac3.b, 0oncentric reducers G Pump dischar2e$ %ertical pipeline etc.

What is the di&&erence bet"een lon2 radius elbo" and short radius elbo".

!ns"er:a, /on2 (adius- #mall pressure drops.b, #hort (adius- i2h Pressure drops.

What is dead le2 on pipin2

!ns"er:it is internal corrosion in pipin2 due to &lo" sta2nant.

What is drip le2

!ns"er: Drain pro%ided to pre%ent internal corrosion or dead le2.

What is the basic di&&erence bet"een Pipe speci&ication !65H @r.! 1 @r.B1 @r.0.

!ns"er: Di&&erence is due to the 0arbon content. o& carbon content.a, !#'4 !65H @r. ! < 5.7A b, !#'4 !65H @r. B < 5.85 c, !#'4 !65H @r. 0 < 5.8A .

What is the di&&erence bet"een pipe speci&ication !#'4 !867 'P 859 = !#'4 !867'P859/$ !#'4 !867 'P 86H = !#'4 !867 'P 86H/

!ns"er : Di&&erence is due to the 0arbon content. 'he /etter J/F denotes lo"er percenta2e o& carbon o& carbon content .

a, !#'4 !867 'P 859 - 5.5 b, !#'4 !867 'P 859/- 5.58Ac, !#'4 !867 'P 86H - 5.5 d, ASTM A312 TP 316L- 5.58A

o" can &lan2es be classi&ied based on &ace &inish

!ns"er:)lan2es are classi&ied based on &ace &inish as

a, #mooth &inishb, #errated &inish

Where the smooth &inish &lan2e = serrated &inish &lan2e &inds its use

!ns"er:'he smooth &inish &lan2e is pro%ided "hen metallic 2as3et is pro%ided and serrated &inish

&lan2e is pro%ided "hen non-metallic 2as3et is pro%ided.



What are the types o& serrated &inish pro%ided on &lan2e &ace

!ns"er:a, 0oncentricb, #piral *Phono2raphic,

o" the serration on &lan2es is speci&ied

!ns"er: 'he serration on &lan2es is speci&ied by the number$ "hich is the !rithmetic !%era2e (ou2h ei2ht *!!(,.

Where the concentric serration is insisted &or &ace &inish

!ns"er:0oncentric serration are insisted &or &ace &inish "here the &luid bein2 carried has %ery lo"

density and can &ind lea3a2e path throu2h ca%ity.

What is the most commonly used material &or @as3et

!ns"er:0ompressed !sbestos )ibre.

Which type o& 2as3et is recommended &or hi2h temperature = hi2h-pressure application

!ns"er:#piral Wound 4etallic @as3et.

What are the criteria &or selection o& 40 o& #piral Wound metallic @as3et "indin2material

!ns"er:'he selection o& material o& construction &or @as3et "indin2 depends upon.

a, 'he corrosi%e nature and concentration o& &luid bein2 carried.b, 'he operatin2 temperature o& the &luid.c, 'he relati%e cost o& alternate "indin2 material.

What are the most common materials used &or spiral "ound metallic 2as3et "indin2

!ns"er: -'he most commonly used material &or spiral "ound metallic 2as3et "indin2 .

a, !ustenitic stainless steel 859 "ith asbestos &iller.b, !ustenitic stainless steel 86H "ith asbestos &iller.

c, !ustenitic stainless steel 876 "ith asbestos &iller.

Which material is used as &iller material &or spiral "ound 2as3et in case o& hi2h temperatureser%ices!ns"er: )or %ery hi2h temperature ser%ices$ 2raphite &iller is use

What is centerin2 rin2 in connection to spiral "ound 2as3et!ns"er: #piral "ound 2as3ets are pro%ided "ith carbon steel external rin2 called centerin2 rin2.



What "ill be the !!( &inish on &lan2e &ace &or usin2 spiral "ound 2as3et!ns"er:

67A-7A5 !!( &inish.

n "hich type o& &lan2es the use o& spiral "ound 2as3et are restricted!ns"er:

!#4E B6H.A does not recommend the use o& 6A5 Kratin2 spiral "ound 2as3et on &lan2es other than "eldin2 nec3 and lapped oint type.

;p to "hat temperature limits the lo" stren2th carbon steel bolts should not be used &or &lan2ed oints!ns"er:

)lan2ed oints usin2 lo" stren2th carbon steel shall not be used abo%e 7550 or belo"70.

;p to "hat temperature the carbon steel materials shall be used!ns"er:

0arbon steel materials shall be used &or temperature up to 97A0.

Which material is used &or temperature abo%e 97H0!ns"er:

!lloy steel materials shall be used &or temperature abo%e 97H0.

Which type o& material is used &or corrosi%e &luid

!ns"er:#tainless steel materials shall be used &or corrosi%e &luid.

Which type o& pipin2 materials are used &or drin3in2 "ater$ instrument air etc

!ns"er:@al%ani?ed steel materials shall be used &or drin3in2 "ater$ instrument air and NI lines */P,.

)rom "hich side o& pipe "ill you ta3e a branch connection

!ns"er:

a, 'op #ide- When &luid is @as$ !ir or #team and 0ryo2enic #er%iceb, Bottom #ide- When )luid is /i+uid.

Why donLt "e ta3e a branch &or 0ryo2enic #er%ice &rom bottom side thou2h the &luid is in

li+uid state

!ns"er:'here is the chance o& ice &ormation durin2 normal operation and since ice &lo"s &rom the

bottom o& the pipe it "ill bloc3 the branch pipe connection. .

Why do "e pro%ide i2h Point ent *P, and /o" Point Drain */PD, in pipin2

!ns"er:



a, P < )or remo%in2 !ir durin2 ydro-testb, /PD < )or drainin2 "ater a&ter conductin2 ydro-test.

.

What are Weldolet and #oc3olet !nd "here they are used

!ns"er:W eldolet and #oc3olet are basically sel&-rein&orced &ittin2s.a, Weldolet -is used &or Butt "eld branch connection "here standard tee is not a%ailable due

to si?e restrictions and the pipin2 is o& critical 1 hi2h-pressure ser%iceb, #oc3olet- is used &or soc3et "eldin2 branch connection$ "hich re+uire rein&orcin2 pad

What is standard len2th o& one strin2 o& pipeline.

!ns"er:C55 meter to 6755 meter

What is the &unction o& %al%es

!ns"er:a, Isolationb, (e2ulationc, Non-(eturnd, #pecial purpose

o" the %al%es are classi&ied based on their &unction!ns"er: Isolation.6. @ate %al%e.7. Ball %al%e8. Plu2 %al%e.9. Piston %al%e.A. Diaphra2m al%e.

H. Butter&ly %al%e.M. Pinch %al%e.

(e2ulation6. @lobe %al%e.7. Needle %al%e.8. Butter&ly %al%e.9. Diaphra2m %al%e.A. Piston %al%e.H. Pinch %al%e.

Non- (eturn6. 0hec3 %al%e.

#pecial purpose

6. 4ulti-Port %al%e.



7. )lush Bottom %al%e.8. )loat %al%e.9. )oot %al%e.A. /ine blind %al%e.H. ni&e @ate %al%e.

o" the %al%es are classi&ied based on end connection

!ns"er:- al%es are classi&ied based on end connection.a, #cre"ed endsb, #oc3et endsc, )lan2ed endsd, Butt "eld endse, Wa&er type ends&, Buttress ends

End connection means arran2ement o& attachment o& the %al%e "ith the e+uipment or the pipin2

What are the types o& chec3 %al%es

!ns"er: - 0hec3 %al%es are di%ided into t"o types based on chec3 mechanism as: -a, /i&t chec3 %al%eb, #"in2

o" did you classi&ied 2as3et

!ns"er :a, !#4E B6H.75 1 !PI -H56: - 4etallic 2as3ets &or pipe &lan2es- #piral "ound$

cta2onal rin2 oint = ac3eted &lan2es.b, !#4E B6H.76 : - Non metallic 2as3et.

What is mean by OPW'L Why it is re+uired

!ns"er: JP#' WE/D E!' '(E!'4EN'F (e+uirements: 'his is done to remo%e residual stress le&t in the oint "hich may cause

brittle &racture.

P4I- Positi%e 4aterial Identi&ication

!ns"er: Detection of correct materials composition

4PI-4a2netic Particle Inspection

!ns"er : Used for the detection of surface and near-surface flaws in ferromagnetic materials.

WP#-Weldin2 Procedure #peci&ication.

WBQ- Weldin2 = Bra?in2 Quali&ication

What do you mean by &ollo"in2 type o& "eldin2

!ns"er:



a, #4!W : #hielded 4etal !rc Weldin2b, 'I@ : 'un2sten Inert @as Weldin2

While "eldin2 o& pipe trunion to pipe1rein&orcement pad you ha%e to put a hole or lea%e someportion o& "eldin2 "hy!ns"er :For venting of hot gas which may get generated due to welding.What is the thumb rule to calculate 0urrent re+uired &or Weldin2!ns"er :Current (Amp) !Diameter of "lectrode (mm) # $%& '%What is the minimum thic3ness o& cs pipe that re+uires stress relie%in2 to be done as per B86.8!ns"er: - .%* mm th+.

What are the common "eldin2 de&ects!ns"er : -

a, /ac3 o& penetrationb, /ac3 o& &usionc, ;ndercut

d, #la2 inclusione, Porosity&, 0rac32, )aulty "eld si?e = pro&ileh, Distortion.

/ac3 o& penetration.,his defect occurs at the root of the oint when the weld metal fails to reach it or weld metal failsto fuse completely the root faces of the oint. As a result a void remains at the root /one whichmay contain slag inclusions.0ause:

A. Use of incorrect si/e of electrode in relation to the form of oint.0. 1ow welding current.

C. Faulty fit-up and inaccurate oint preparation.

/ac3 o& &usion.1ac+ of fusion is defined as a condition where 2oundaries of unfused metal e3ist 2etween the4eld metal 5 2ase metal or 2etween the adacent layers of weld 6metals.0ause:

A. 7resence of scale dirt o3ide slag and other non-metallic su2stance which preventsthe weld metal to reach melting temperature.0. 8mproper deslagging 2etween the weld pass.Precaution: -

A. 9eep the weld oint free from scale dirt o3ide slag and other non- metallic su2stance.0. Use adeuate welding current.C. Deslag each weld pass thoroughly.

D. 7lace weld passes correctly ne3t to each other.

;ndercut,his defect appears as a continuous or discontinuous groove at the toes of a weld pass and islocated on the 2ase metal or in the fusion face of a multipass weld. 8t occurs prominently on theedge of a fillet weld deposited in the hori/ontal position.

0ause: A. "3cessive welding current.



0. ,oo high speed of arc travel.C. 4rong electrode angle.(ecti&ication: -,he defect is rectified 2y filling the undercut groove with a weld pass. 8f undercut is deep 5contains slag it should 2e chipped away 2efore rewelding.

#la2 Inclusion;on6metallic particles of comparatively large si/e entrapped in the weld metal are termedas slag inclusion.0ause:

A. 8mproper cleaning of slag 2etween the deposition of successive passes.0. 7resence of heavy mill scale loose rust dirt grit 5 other su2stances present on thesurface of 2ase metal.Precaution: -

A. Clean the slag thoroughly 2etween the weld pass.0. 9eep the oint surface (especially gas cut surface) and 2are filler wire perfectly clean.C. Avoid undercut 5 gaps 2etween weld pass.D. Use proper welding consuma2les.

Porosity

,he presence of gas pores in a weld caused 2y entrapment of gas during solidification istermed as porosity. ,he pores are in the form of small spherical cavities either clustered locallyor scattered throughout the weld deposit. <ometimes entrapped gas give rise to a single largecavity called 0lowholes.0ause:

A. Chemically imperfect welding consuma2les for e3ample deficient in deo3idiser.0. Faulty composition of 2ase material or electrode for e3ample high sulphur content.C. 7resence of oil grease moisture and mill scale on the weld surface.D. "3cessive moisture in the electrode coating or su2merged-arc flu3.". 8nadeuate gas shielding or impure gas in a gas 6shielded process.F. 1ow welding current or too long an arc.=. >uic+-free/ing of weld deposit.

0rac3Fracture of the metal is called crac+. ,wo types of crac+s: - Cold crac+ 5 ?ot crac+.Cold crac+ usually occur in ?A@ of the 2ase metal when this /one 2ecomes hard and 2rittle dueto rapid cooling after the weld metal has 2een deposited 5 sufficient hydrogen has 2eena2sor2ed 2y the weld metal from the arc atmosphere.Precaution:

A. Use of low car2on euivalent materials.0. ?igher heat input during welding.C. 7reheating.D. Use of low hydrogen electrode.@. )aulty "eld si?e and pro&ile

A weld is considered faulty if it has lac+ of reinforcement e3cessive reinforcement or irregular



Distortion0ecause a weldment is locally heated (2y most welding processes) the temperaturedistri2ution in the weldment is not uniform and changes ta+e place as welding processes.,ypically the weld metal and the 2ase metal heat-affected /one immediately adacent to it areat a temperature su2stantially a2ove that of the unaffected 2ase metal. As the molten poolsolidifies and shrin+s it 2egins to e3ert shrin+age stresses on the surrounding weld metal andheat-affected /one area. 4hen it first solidifies this weld metal is hot relatively wea+ and cane3ert little stress. As it cools to am2ient temperature however the shrin+age of the weld metale3erts increasing stress on the weld area and eventually reaches the yield point of the 2asemetal and the heat-affected /one. esidual stresses in weldments have two maor effects. Firstthey produce distortion and second they may 2e the cause of premature failure in weldments.Distortion is caused when the heated weld region contracts nonuniformly causing shrin+age inone part of the weld to e3ert eccentric forces on the weld cross section.,he distortion may appear in 2utt oints as 2oth longitudinal and transverse shrin+age or contraction and as angular change (rotation) when the face of the weld shrin+s more than theroot.Distortion in fillet welds is similar to that in 2utt welds: transverse and longitudinal shrin+age aswell as angular distortion results from the un2alanced nature of the stresses in these welds.

Why pre-heatin2 is done on some pipe be&ore startin2 "eldin2!ns"er: -'o slo" do"n the coolin2 rate.

Why post-heatin2 is done on some pipe a&ter the "eldin2 is o%er!ns"er: -'o maintain uni&orm homo2eneous structure.

What is the pre-heat temperature &or carbon steel abo%e 6C.5A44 th3.!ns"er: -Pre <heat temperature &or carbon steel abo%e 6C.5A mm is 50.

Is post heatin2 re+uired &or carbon steel material abo%e 6C.5A44 th3.!ns"er: -No. Post heatin2 is not re+uired &or carbon steel material o& any thic3ness .

What is the soa3in2 temperature durin2 stress reli%in2 &or carbon steel material!ns"er: -#oa3in2 temperature &or carbon steel material durin2 stress reli%in2 is H750. *750)

What is the soa3in2 period durin2 stress reli%in2 &or carbon steel material!ns"er :- #oa3in2 period &or carbon steel material durin2 stress reli%in2 is 6hr.

What is the rate o& heatin2 = coolin2 durin2 stress reli%in2 &or carbon steel material!ns"er: -,he rate of heating 5 cooling for car2on steel material during stress reliving is *%cBhr.

What is the pre-heat temperature durin2 stress reli%in2 &or alloy steel materials!ns"er: -7re-heat temperature for A< materials is %C.

What is the soa3in2 temperature durin2 stress reli%in2 &or alloy steel material!ns"er: -<oa+ing temperature for alloy steel material is '%C('%C).



What is the soa3in2 period durin2 stress reli%in2 &or alloy steel material!ns"er: -<oa+ing period for alloy steel material is 'hrs.

What is the rate o& heatin2 = coolin2 durin2 stress reli%in2 &or alloy steel material!ns"er: -,he rate of heating 5 cooling for alloy steel material is %%CBhr.

What is the post heat temperature &or alloy steel material!ns"er: -7ost heat temperature for alloy steel material is E%%

Where the use o& electrode EM56 is recommended!ns"er: -,he use of electrode "% is recommended for welding the following: -

A. For high strength steel.0. For high thic+ness car2on steel plates.C. ?igher car2on euivalent material.

What should be the content o& chlorine in "ater "hile conductin2 hydrotest &or 0# = ##

pipes!ns"er: -For C< 6 '*% 77.For << 6 E% 77..

Questions related to pipes supports:

What are the 0riteria &or Pipe #upportin2!ns"er: -Following are the points which should 2e ta+en into account for proper supporting: -

A. 1oad of 2are pipe G fluid G insulation (if any).0. 1oad of 2are pipe G water fill.C. 1oad of valves and online euipment and instrument.

D. ,hermal loads during operation.". <team out condition if applica2le.F. 4ind loads for piping at higher elevation if reuired.=. Forced vi2ration due to pulsating flow.?. 0are pipe with si/e a2ove 'H shall 2e supported with 7ad or <hoe.

What is the basic span o& supports &or 7F1HF165F179F pipe!ns"er: -0asic <pan is *.*m B m B .*m B *m respectively.

What is the &unction o& pro%idin2 the anchor$ cross 2uide and 2uide &or pipin2!ns"er: -

Anchor is provided to restrict all the a3ial and rotational movements of pipe whereas cross guide is

provided to restrict displacements of pipe along with the a3is perpendicular to its centerline and =uideis provided to restrict the longitudinal movements of pipes along with its a3is.

o" is pipin2 to 'an3 inlet no??le is supported and "hy!ns"er: -7iping to ,an+ ;o//le is supported with spring type support (first support from ;o//le) in order toma+e the no//le safe from the loads which occurs due to the displacement of pipe ( Displacementmay 2e due to thermal e3pansion of pipe tan+ material tan+ settlement etc).



What are the types o& &lexible sprin2 han2ers!ns"er: -. Constant <pring ?anger '. Iaria2le <pring ?anger.What is the purpose o& pro%idin2 @raphite Pads in supports belo" shoes!ns"er: -

,o reduce the friction factor. ,he co-efficient of friction for =raphite 7ads is %. Where do you pro%ide !nchor and #lotted #upport o& eat Exchan2er!ns"er: -

Anchor support of ?eat e3changer is provided on the side from which ,u2e 2undle will 2e pulled outfor the purpose of maintenance wor+ also it is 2ased on the growth of the connecting piping ase3changer should grow with the piping.

What should be the material o& shoes &or supportin2 !# pipes = "hy!ns"er: -8f C< shoes are used then pad in contact with the pipe shall 2e of Alloy steel to avoid dissimilar welding at pipe. ,o avoid alloy steel welding and dissimilar welding fa2ricated clamps either of C< or << can 2e used.

What are s"ay braces

!ns"er: -<way 2races are essentially a dou2le acting spring housed in a canister. ,heir purpose is to limit theundesira2le movement. Undesira2le movement means movement caused 2y wind loading rapidvalve closure relief valve opening two phase flow or earthua+e.What is the di&&erence bet"een

%ariable sprin2 han2er and constant sprin2 han2er!ns"er: -Iaria2le spring ?anger: -

As the name itself indicates the resistance of the coil to a load changes during compression.Constant spring ?anger: -Constant spring hanger provides constant support force for pipes and euipment su2ected to verticalmovement due to thermal e3pansion.

Questions related to (adio2raphy technolo2y:

What are the types o& radiation emitted by isotopes!ns"er: -,here are three types of radiation as: -!. Alpha particle (- particle).B. 0eta particles (- particle).0. =amma ray (- ray).

What is the char2es on - particle$- particle and - ray = compare their relati%e penetration!ns"er: -Charges on radiation are: -

A. Alpha particle (- particle) : - 7ositive charge 5 less penetrating in comparison to - particle 5- ay. ,hey can 2e stopped 2y a thin sheet of paper.0. 0eta particles (- particle) : - ;egative charge 5 have definite range of penetration. "asilya2sor2ed in the matter.C. =amma ray (- ray) : - ;o charge 5 highly penetrating.



Name the isotopes$ "hich emits 2amma ray!ns"er: -=amma ray source are: -

A. 8ridium 6 '0. Co2alt 6 J%C. Cesium 6 ED. ,hulium 6 %

Name the 2amma ray source used &or industrial radio2raphy "or3!ns"er: -

A. 8ridium 6 '0. Co2alt 6 J%

What is the depth o& penetration in steel by cobalt < H5$ cesium < 68M$ Iridium < 6C7 ='hulium< 6M5.!ns"er: -7enetration in steel 2y: -

A. Co2alt 6 J% : - inch.0. Cesium 6E : - E K inch.

C. 8ridium 6 ' : - E inch.D. ,hulium6% : - K inch.

What do you mean by photo2raphic Density!ns"er: -8t is the uantitative measurement of film 2lac+ness. 8t is e3pressed as: -D 1og I0/It L. L where D is density.I% - 1ight intensity incident on the film.It - 1ight intensity transmitted through the film.

Name the instrument used &or measurin2 density o& photo2raphic or radio2raphic &ilm!ns"er: -Densitometre is an instrument for measuring the density of photographic and radiographic film.

What are the &actors on "hich the density o& radio2raphic &ilm depends!ns"er: -,he density of radiographic films depends upon the following: -

A. ,otal amount of radiation emitted 2y #-ray or gamma ray.0. Amount of radiation reaching the specimen.C. ,he amount of radiation passing through the specimen.D. 8ntensifying action of the screen if used.

o" the intensity o& source is related "ith &ilm distance!ns"er : -8ntensity of #-ray or gamma ray varies inversely with the suare of the distance from focal spot or source of light. ,his relation is +nown as the 8nverse suare law.athematically it is e3pressed as: -I1 = D2

2

I2 D1

2

… 4here I1 and I2 are intensities at the distance D1 and D2 respectively.



What are the 2o%ernin2 &actors &or exposure &rom particular radioisotopes!ns"er: -,here are three factors for governing the e3posure with a given +ilovoltage for #- ray or with thegamma ray from particular radioisotopes.

A. illiamperage (#-ray) or source strength (for =amma ray).0. Focal spot to film distance or source to film distance.C. ,ime of e3posure.

What is the relation bet"een 4illiampera2e *source stren2th, and &ilm distance!ns"er: -,he illiamperage () is directly proportional to the suare of the focus to film distance (D). ,heeuation is e3pressed as: -

M1 D12

M2 D22

…4here M1 and M2 are the illiamperage.

D1 and D2 are the distance from focus to film.

What is the relation bet"een exposure time = &ilm distance!ns"er: -,he e3posure time (,) is directly proportional to the suare of the focus to film distances (D).,he euation is e3pressed as :

T1 D12

T2 D22

What is the relation bet"een #ource stren2th = exposure time!ns"er: -,he illiamperage () is inversely proportional to the time of e3posure (,). ,he euation ise3pressed as: -

M1 T2 or M1 T1 M2 T2

M2 T1

…4here M1 and M2 are the illiamperage.

T1 and T2 are the time of e3posure.

;ote: ,he a2ove relation is also called eciprocity law and is true for direct #-ray or gamma ray withlead screen e3posure. ,he a2ove relation is not uit accurate for e3posure to light.

o" the source stren2th o& radio2raphic isotopes expressed!ns"er: -,he source strength of radiographic isotopes e3pressed in terms of Curie.

What do you mean by exposure!ns"er: -8t is defined as the uantity of # or gamma radiation that produces in air ions carrying coulom2 (C)of charge ( of either sign) per 9g of air. ,he unit of e3posure is CB9g.

What do you mean by (oent2en!ns"er: -oentgen is the old unit for e3posure. 8t is defined as the amount of # or gamma radiation whichli2erates e s u of charge of either sign in C. C of air at < , 7. e s u B C C of air at <,7. '.* # %$ CB 9g air.



What is Dose e+ui%alent!ns"er: -Dose "uivalent >uality factor # a2sor2ed dose.>uality factor generally considered as:

A. for #or.0. E for ,hermal neutrons.C. '% for- particles.,he unit of dose euivalent is <ievert (<I).Formerly the unit of dose euivalent was rem. <ievert %%rem ( oentgen).

What is the &unction o& radio2raphic screens!ns"er: -8t intensifies the radiographic images on the f ilm.

What are the types o& radio2raphic screens 2enerally used!ns"er: -,ypes of radiographic screens generally used are: -

A. 1ead screen.0. Fluorescent screen or salt screens.

What are the types o& /ead screens!ns"er: -,ypes of 1ead screens are: -

A. 1ead foil screen.0. 1ead o3ide screen.

What do you mean by intensi&ication &actor * I),!ns"er: -"3posure time reuired to produce reuired film density without screen.8ntensification factor "3posure time for same density using screen.8n the a2ove definition it is assumed that same film and radiation source used for the 2oth the

"3posure.What are the &actors upon "hich the intensi&ication &actor depends!ns"er: -8ntensification factor due to metallic screens depends on the following: -

A. etal of foil.0. ,hic+ness of foil.C. "nergy of radiation.D. <pecimen thic+ness.

o" the intensi&ication &actor depends on metal o& &oil!ns"er: -For a given radiation source the num2er of electrons produced depends on the nature of the metal

foil. 8ntensification factor increases with atomic num2er of the metal. For gamma ray radiographygenerally 1ead screen are used.

o" the intensi&ication &actor depends on thic3ness o& &oil!ns"er: -



,he intensification factor increases with the increase in the thic+ness of the foil. 8ntensificationincreases ma3imum corresponding to the range of photoelectron in that metal. After further increase itremains practically constant. 8f the thic+ness further increased greater num2er of gamma photons will2e attenuated and this will reduce the produce of photoelectrons.

o" the intensi&ication &actor depends on ener2y o& radiation!ns"er: -ore is the energy of radiation more is the intensifying action.

o" the intensi&ication &actor depends on thic3ness o& the specimen!ns"er: -

A specimen placed in 2etween the source and film performs following two functions: - A. 8t filters the primary radiation.0. =ives low energy scattered radiation.,he radiographic screen can have different sensitivities for primary radiation and the radiation given2y the a2ove two effects. ?ence the change in intensification factor with o2ect thic+ness is e3pected.,he intensification of low energy scattered radiation is more than the intensification of high energyfiltered radiation.

Where the &luorescent screen &inds its use

!ns"er: -,he fluorescent screens are widely used for medical purpose to reduce the e3posure time.

What are the main constituents o& a radio2raphic &ilm!ns"er : -,he radiographic films consist of the following: -

A. 0ase material.0. <u22ing layer.C. "mulsion andD. 7rotective layerB <uper coat. What is the di&&erent base material tried so &ar &or radio2raphic &ilm!ns"er: -,he materials so far tried for 2ase is: -

A. =lass.0. Cellulose ;itrate.C. Cellulose Acetate.D. Cellulose ,riacetate.". 7olyester ( ost suita2le material to 2e used as 2ase material).What is the &unction o& #ubbin2 material$ Emulsion = protecti%e layer in radio2raphic &ilm!ns"er: -#ubbin2 material : - 8t provides the stic+y action to the emulsion as the emulsion does notadhere directly on the 2ase material.Emulsion : - 8t contains silver 2romide gelatin ( =enerally animal 2one marrow)Protecti%e /ayer : - 8t is coated on emulsion in order to protect the same from physicaldamage a2rasion and stress mar+.

o" the (adio2raphic &ilms are classi&ied!ns"er: -,he adiographic films are classified as: -

A. Class 6 8 : - ?ighest contrast 1owest speed.0. Class 6 88 : - ?igh contrast 1ow speed.C. Class 6 888 : - edium contrast edium speed.D. Class 6 8I : - 1ow contrast ?igh speed.



What is the basis o& classi&ication o& radio2raphic &ilm!ns"er : -Classification of adiographic film is done on the 2asis of grain si/e of <ilver 0romide (<ilver 0romideCrystals). Finer the grain si/e of <ilver 0romide in emulsion slower will 2e the speed. =enerally usedcrystal si/e is %.'' %.*' %.J %.% and micron. What is speed "ith re&erence to (adio2raphy &ilm!ns"er : -8t can 2e defined as the density records on the film resulting from a given e3posure. 8t is inverse of e3posure reuired to produce on radiograph of particular density under the specified conditions. Afilm reuires less e3posure to achieve particular density is called fast film and more e3posure calledslow film. What type o& &ilm is 2enerally used &or (adio2raphy!ns"er: -Class 6 888 type ( D*D 6 Agfa ma+e) film is generally used for radiography.

What type o& &ilm is not used &or industrial purpose *;sed &or 4edical purpose,!ns"er: -

Class 6 8I type ( D% 6 Agfa ma+e) film is not used for industrial purpose.

What do you mean by &ilm processin2!ns"er :-4 hen the film is e3posed to the radiation creates latent image or invisi2le image 2y convertingthesilver 2romide present in the emulsion into metallic silver. ,he e3posed film when processed convertslatent image into visi2le image.

What are the main steps in &ilm processin2!ns"er: -ain steps in film processing are: -

A. Developing0. <top 2ath.C. Fi3ture.D. 4ashing". Drying.

What are the in2redients o& De%eloper!ns"er: -

A. Developing Agent : - etol ?ydrouinone and 7encilone.0. Accelerator : - <odium car2onate.C. estrainer : - 7otassium 0romate.D. 7reservative : - <odium <ulphate.

What is the ideal de%elopin2 temperature!ns"er: -0elow C and a2ove '$C developing is not recommended.What is the de%elopin2 time 2enerally recommended!ns"er: -* to minutes. 1arger developing time increases the fog density. ,he developing time 2elow Eminutes is not recommended as the reuired density shall not 2e achieved and may miss minor discontinuities



o" do you calculate the "idth o& Pipe rac3!ns"er :-4 (f # n # s) G A G 0.L4here & : <afety Factor .* if pipes are counted from 7FD. .' if pipes are counted from 758D.n : num2er of lines in the densest area up to si/e $*%;0. E%% mm ("stimated average spacing) ''* mm (if lines are smaller than '*% ;0)! : Additional 4idth for: 6: 1ines larger than $*% ;0.: For instrument ca2le tray B duct.: For "lectrical ca2le tray.s : E%% mm (estimated average spacing): ''* mm (if lines are smaller than '*% ;0)B : future provision '%M of (f # n # s) G A

What is !llo"able #tress!ns"er:-8t is defined as ultimate tensile strength divided 2y factor of safety. ,he safety factor is o2viouslygreater than . Design which ensure that the stress value anywhere in the structure is less than thisallowa2le stress are considered safe as they do not allow the structure element to come anywhereclose to the point where plastic insta2ility leading to disruption or disintegration of element would setin.

Questions (elated to pipe under stress:-

What do you mean by oop #tresses and ho" do you calculate it!ns"er: -<tresses which are generated circumferentially due to the action of 8nternal pressure of pipe are called

?oop <tress. 8t is calculated 2yN -?oop <tress (<h) 7do B 't4here 7 Force Acting from 8nside.do OD of 7ipe.t 7ipe ,hic+ness.

o" does oop #tress a&&ect the system!ns"er: -

As per mem2rane theory for pressure design of cylinders as long as hoop stress is less than yieldstress of oc the design is safe. ?oop stress induced 2y thermal pressure is twice the a3ial stress(<1). ,his is widely used for pressure thic+ness calculation for pressure vessel.

oopeLs or 0ircum&erential #tress,he internal pressure also induces stresses in the circumferential direction as shown in figure.#

r o r r iP#



oopeLs #tress Due to Internal Pressure.,he stresses are ma3imum for grains situated at the inner radius and minimum for those situatedat the outer radius. ,he ?oopePs stress at any point in 2etween radial position (r) is given as:-<? at r 7r i' G r i'r o')B r o' 6 r i') ----------------- (1amePs euation)From mem2rane theory <? is calculated as:-<? 7doB 't or 7diB 't(adial #tressFor thin walled pipes the radial stress variation can 2e neglected.adial stresses are also induced due to internal pressure as shown in figure.7atm or 7e3t

77

(adial #tresses Due to Internal Pressure. At the outer s+in the radial stress is compressive and eual to the atmospheric pressure (7atm) or e3ternal pressure (7e3t) on the pipe. At the inner radius it is also compressive 2ut eual toa2solute fluid pressure (7a2s). 8n 2etween it varies. 0ut it is often neglected.0. Bendin2 /oad:-7ipe 2ending is caused mainly due to two reasons:!. Uniform weight loadB. Concentrated weight load.

;ni&orm Wei2ht /oad. A pipe span supported at two ends would sag 2etween the supports due to the following:!. <elf weight of the pipe and weight of the insulation when not in operation.B. <elf weight and weight of hydrostatic test fluid during hydrostatic test.

0. <elf weight weight of insulation and weight of fluid it is carrying during operation. All these weights are distri2uted uniformly across the unsupported span and lead to ma3imum2ending moment either at the centre of the span or at the end points of the span.1et the total weight of the pipe insulation and fluid 2e 4 and the length of unsupported span 2e 1as shown in figure.7inned <upport.,otal 1oad4Fi3ed <upport.

;ni&ormly Distributed /oad.,he weight per unit length w 4B1,he ma3imum 2ending moment (ma3) whichoccurs at the centre for the pinned support. ma3. w1'B

For fi3ed support the ma3imum 2endingmoment occurs at the end. ma3 w1'B',he pipe configuration and support used in process industry do not confirm to any of the a2oveideal support and is considered somewhere in 2etween. ,he common practice is to use thefollowing average formula to calculate 2ending moment for practical pipe configuration.ma3. w1'B%



0oncentrated Wei2ht /oad.,he e3ample of concentrated load is a valve on a pipe run.Pointed loadPinned #upporta b/a b )ixed support./,he load is acting at the centre of gravity of the valve and the ma3imum 2ending moment occurs atthe point of loading for pinned support is given 2y:ma3. 4 a 2 B 1For rigid support the ma3imum 2ending moment occurs at the end nearer to the pointed load and isgiven 2y:ma3. 4a'2B1' (QaP is ta+en as the longer of two arm in using the formula.)

,he 2ending moment in the a2ove case can 2e reduced to /ero 2y ma+ing either QaP or Q2P /ero i.e.locating one of the supports right at the point where the load is acting. 8n actual practice it would

mean supporting the valve itself. As it is not possi2le the common practice is to locate one of thesupports as close to the valve (or any other pointed and significant load). 0y this the 2endingmoment due to pointed load is minimal and can 2e neglected.

!xial #tress due to Bendin24aximum compressi%e stress.4b

Natural !xis4aximum 'ensile stress.4henever the pipe 2ends the s+in of the pipe wall e3periences 2oth tensile and compressivestresses in the a3ial direction as shown in the figure. ,he a3ial stress changes from ma3imum tensileon one side of the pipe to ma3imum compressive on the other side. O2viously there is natural a3isalong which the 2ending moment does not induce any a3ial stress. ,his is also the a3is of the pipe.

,he a3ial tensile stress for 2ending moment 2 at location c as measured from natural a3is is given2y:<1 2 c Bis the moment of inertia of the pipe cross-section. For a circular cross-section pipe is given 2y:(do

$ 6 di

$) B J$,he ma3imum tensile stress occurs where c is eual to the outer radius of the pipe and is given 2y:<1 at outer radius 2 r o B 2B@4here @ (Br o) is the section modulus of the pipe.D. #hear /oad:- #hear )orce on a pipe<hear force (I) acting on the pipe is shown in the figure. 8t causes shear stresses which arema3imum along the pipe a3is and minimum along the outer s+in of the pipe. ,his is e3actly oppositeof the a3ial stress pattern caused 2y 2ending moment. ,hese stresses are small in magnitude hencenot ta+en in account in pipe stress analysis. 8f necessary these are calculated as:ma3. I>BAm where > is shear form factor and Am is metal cross-section.E. 'orsional /oad:-

r 4'

,his load causes shear stresses. ,he shear stress caused due to torsion is ma3imum atouter pipe radius. ,he ,orsional moment is given 2y:(at r r o) , r o B, , r o B('8) ,B ' @



where , is the ,orsional resistance twice the moment of inertia.r or r i

What are the 'heories o& &ailure

!ns"er:-8mportant theories in common use are:-!. a3imum <tress ,heory or an+ine ,heory.B. a3imum <hear ,heory or ,resca ,heory.0. Octahedral <hear ,heory or Ion ises ,heory.

What is 4aximum stress theory!ns"er:- According to this theory failure occurs when the ma3imum principal stress in a system (<) isgreater than the ma3imum tensile principal stress at yield in a specimen su2ected to unia3ial test. 8n unia3ialtest the applied load give rise to a3ial stress (<1) only and ?oopePs stress (<?) 5 adial stress (<)as well as the shear stress are a2sent. 8n a specimen under unia3ial tension test at yield the followingholds.

<1 <R <? % < %< <R <' % and <E %,he ma3imum tensile principle stress at yield is thus eual to the conventionally reported yield stress(load at yield B cross- sectional area of specimen)'he (an3ine theory thus says that the &ailure occurs "hen the maximum principal stress in asystem *#6, is more than the yield stress o& the material *# ,. What is 4aximum #hear 'heory!ns"er:-

According to this theory the failure occurs when the ma3imum shear stress (ma3) is greater than the

ma3imum shear stress at yield in a specimen su2ected to unia3ial tension test.

ma3. %.*(<1 6 <?)' G $'%.*

<ince in the unia3ial tension test <? and is @ero. ,hus

ma3

<1

B' <R

'he 'resca 'heory thus says that the &ailure occurs "hen the maximum shear stress in a

system *max, is more than hal& the yield stress o& the material.

What is ctahedral #hear 'heory!ns"er:-

According to this theory the failure occurs when the octahedral shear shear stress in a system (oct.)

is greater than the octahedral shear stress at the yield in a specimen su2ected to unia3ial tensiontest. ,he octahedral shear stress is given 2y:

oct BE(< - <')' G (<' 6 <E)' G (<E 6 <)'%.*

,he octahedral shear stress at yield in the specimen su2ected to unia3ial tension test is given 2y:

oct 'BE <R

%.*

Questions (elated to #tress !nalysis:-What is the obecti%e o& stress analysis!ns"er: -!. ,o ensure that the stresses in piping components in the system are within allowa2le limits.B. ,o solve dynamic pro2lems developed due to mechanical vi2ration fluid hammer pulsation relief valves etc.



0. ,o solve pro2lems associated due to higher or lower operating temperature as: -I. Displacement stress range.II. ;o//le loading on connected euipment.III. 7ipe displacements.I.1oads 5 moments on supporting structure.

What are the steps in%ol%ed in stress analysis *or any stress pac3a2e carries out,

!ns"er: -!. 8dentify the potential loads that the piping system would encounter during the life of the plant.B. elate each of these loads to the stresses and strains developed.0. =et the cumulative effect of the potential loads in the system.D. Decide the allowa2le limits the system can withstand without failure as per code.E. After the system is designed to ensure that the stresses are within safe limits.

o" the loads are classi&ied in stress analysis pac3a2e!ns"er: -!. <ustained 1oads : ,hose due to forces present during normal operation.B. Occasional 1oads : ,hose present during rare intervals of operation.0. Displacement 1oads : ,hose due to displacement of pipe.(<elf-limiting stresses due to thermal effects).

What are the sources o& sustained load 2enerated in pipin2 system!ns"er: -!. 8nternal fluid pressure.B. Dead weight of 7ipe with fluid and its attachments.<ustained load is calculated as: -4eight of 7ipe with Fluid G 8nternal fluid pressure load G 1oad due to springs (4G7).

What are the Inputs re+uired &or stress analysis o& a pipin2 system!ns"er: -!. 7ipe <i/e.B. Fluid ,emperature.0. 7ipe aterial.

D. odel.E. Design pressure.). 8nsulation ,hic+ness.@. <pecific gravity.. Friction coefficient.

o" do you calculate the operatin2 load!ns"er:-4 G7G,, 6 1oad due to thermal e3pansion.

@i%e some Examples &or occasional /oads.!ns"er: -!. 4ind load.B. <eismic load.0. Forces due to relief or 2low down.D. 7ressure wave generated due to water hammer effects.

What is the &ailure theory subscribed under !#4E B86.8



!. 4aximum principal stress theory *(an3ines 'heory,.B. 4aximum #hear 'heory.0. ctahedral #hear 'heory.!ns"er: - A. a3imum principal stress theory or an+ines theory.

#elect the &ailure stress ran2e &or &ati2ue &ailure due to thermal expansion as per B86.8!. #! G *#c #h, 6.H& B. #! G 6.7A *#0 #h,0. #! G *6.7A #c5.7A#h,& Where$ #! G !llo"able Expansion stress (an2e.#c and #h G Basic !llo"able material stress in cold = hot conditions respecti%ely.& G #tress ran2e reduction &actor *6 &or M555 cycles.,!ns"er: - C

What is the desired li&e cycle &or Pipin2 in operation!ns"er: -Desired life cycle for 7iping in operation is '% Rears (%%% Cycles).,he normal no. of cycles for which the displacement or thermal stresses are designed is %%% cycles.

o" do you calculate the stress de%eloped due to thermal expansion

!ns"er : -

<tress developed " 3 (1B1)

LL. 4here " RoungPs odulus.1 8ncrease in length due to thermal e3pansion.1 Original 1ength of the pipe.

o" do you calculate the thermal expansion in a pipe!ns"er : -1 3, 3 18n the codes and many reported calculationsis used as inclusive of,. ,hus the a2ove formula iswritten as:-1 3 14here Coefficient of thermal e3pansion from am2ient to operating temperature.1 1ength of the pipe.

o" much should be the pressure &or ydro-'est!ns"er : -?ydrotest pressure should 2e calculated as follow e3cept as provided against point ;o D.!. .* ,imes of Design 7ressure.B. For a design temperature a2ove the test temperature minimum test pressure can 2e calculated as:7t (.* # 7 # <t) B <LLL..4here 7t : inimum ,est 7ressure.7 : 8nternal design pressure.<t: Allowa2le stress at test temperature.< : Allowa2le stress as design temperature.

.0. 8f a test pressure as per a2ove would produce a stress in e3cess of the yield strength at testtemp.the test pressure may 2e reduced to ma3imum pressure that will not e3ceed the yieldstrength at test temp.D. 8f the test pressure of piping e3ceeds the vessel pressure and it is not considered practica2le to

Why do "e pro%ide Drip /e2 in #team /ine!ns"er : -,o remove condensate when there is a rise of same in the pipe along the flow direction. 8f drip leg is



not provided in steam line the condensate which forms inside the pipe will result in 4ater ?ammer effect causing damage to piping system.

Why loop is pro%ided in pipin2 system!ns"er: -,o adust thermal e3pansion.

What is the maximum expansion absorbed in loops in normal desi2n!ns"er : -% 8nches.

What is the allo"able stress ran2e &or 0# pipes!ns"er : -'%% +gBcm'.

Describe di&&erent types o& destructi%e and non-destructi%e tests!ns"er: -D"<,UC,8I" ,"<,: 0end test ,ensile test 8mpact test and ?ardness test.;O;-D"<,UC,8I" ,"<,: D7, 7, adiography and ultrasonic test

What are the di&&erent types o& hardness tests carried out!ns"er: -0rinell ?ardness ,est.oc+well ?ardness ,est.Iic+er ?ardness ,est.

What is the relation bet"een Brinell ardness No. and (oc3"ell ardness No.!ns"er : -'' ?C (oc+well ?ardness) 'E 0?; (0rinell ?ardness ;o) ?arder.

What are di&&erent types o& pumps!ns"er: -0asically there are two types of pumps.

!. Centrifugal 7ump.B. 7ositive Displacement pump. What are the di&&erent types o& centri&u2al pump!ns"er: -Different types of Centrifugal 7ump are: -!. <ingle <tage or B. ulti-stage

What is the basic di&&erence bet"een sin2le sta2e and multi-sta2e centri&u2al pump!ns"er: -,he <ingle stage pump has one impeller and multi-stage pump has two or more impellers in series.,he discharge of one impeller is the suction of the ne3t one and the head developed in all the stagesare totaled.

o" many types o& centri&u2al pump are a%ailable based on the #uction and Dischar2earran2ement!ns"er: -



0ased on the suction and discharge arrangement the type of centrifugal pumps availa2le is: -!. "nd <uction ,op Discharge.B. ,op <uction ,op Discharge.0. <ide <uction <ide Discharge.

What are the main components o& a centri&u2al pump!ns"er: -

A centrifugal pump has two main components as:-!. A rotating component comprised of an impeller and a shaft.B. A stationary component comprised of a casing casing cover and 2earings.

De&ine the "or3in2 mechanism o& centri&u2al pump!ns"er: -

A centrifugal pump is one the simplest pieces of euipment in any process plant. 8ts purpose is toconvert energy of prime mover (an electric motor or tur2ine) first into velocity or +inetic energy andthen into pressure energy of a fluid that is 2eing pumped. ,he energy changes occur 2y virtue of twomain parts of the pump the impeller and the volute or diffuser. ,he impeller is rotating part thatconverts drivers energy into the +inetic energy. ,he volute or diffuser is the stationary part thatconverts the +inetic energy into pressure energy.

o" the centri&u2al &orce 2enerated in the centri&u2al pump!ns"er: -,he process liuid enters the suction no//le and then into the eye (center) of the revolving device+nown as an 8mpeller. 4hen the impeller rotates it spines the liuid sittings in the cavities 2etweenthe vanes outward and provides centrifugal acceleration. As the liuid leaves the eye of the impeller alow 6 pressure area is created causing more liuid to flow towards the inlet. 0ecause the impeller 2lades are curved the fluid is pushed in a tangential and radial direction 2y centrifugal force. ,hefigure 2elow depicts a side cross-section of a centrifugal pump indicating the movement of the liuid.

ne &act that must al"ays be remembered: ! pump does not create pressure$ it only pro%ides&lo". Pressure is a ust an indication o& the amount o& resistance to &lo".

What do you mean by 0a%itation in Pump!ns"er: - A pump is designed to handle liuid not vapor. ,he satisfactory operation of pump reuires thatvapori/ation of the liuid does not occur at any condition of operation. ,his is so desired 2ecausewhen a liuid vapori/es its volume increases very much. For e3ample ftE of water at roomtemperature 2ecomes %% ftE of vapor at the same temperature. ,he vapori/ation 2egins whenvapor pressure of the liuid at the operating temperature euals the e3ternal system pressure whichin an open system is always eual to atmospheric pressure. Any decrease in e3ternal pressure or risein operating temperature can induce vapori/ation. ,he vapor pressure occurs right at the impeller inlet where a sharp pressure drop occurs. ,he impeller rapidly 2uilds up the pressure whichcollapses vapors 2u22les causing cavitation and damage the pump internals. ,his is avoided 2ymaintaining sufficient ;7<?. (Cavitation implies cavities or holes in the fluid we are pumping. ,heseholes can also 2e descri2ed as 2u22les so cavitation is really a2out the formation of 2u22les andtheir collapse. 0u22les form whenever liuid 2oils. 8t can 2e avoided 2y providing sufficient ;7<?.)

What do you mean by NP# or NP#r !ns"er:-4 hen the liuid passes from the pump section to the eye of the impeller the velocity increasesandthe pressure decreases. ,here are also pressure losses due to shoc+ and tur2ulence as the liuidstri+es the impeller. ,he centrifugal force of the impeller vanes further increases the velocity anddecreases the pressure of the liuid. ,hus the ;et positive suction ?ead reuired (;7<?r ) or sometimes in short as ;7<? is the total head at the pump section to overcome these pressure dropsin the pump and maintain the maority of the liuid a2ove its vapor pressure.



,he term S;",H refers to the actual pressure head at the pump section flange and not the staticsection head. ;7<? reuired is a function of the pump design and is determined 2ased on actualpump test 2y vendor.

What do you mean by NP#a *Net positi%e suction head a%ailable,!ns"er: -;et 7ositive <uction ?ead Availa2le is a function of the system in which the pump operates. 8t is thee3cess pressure of the liuid in feet a2solute over its vapor pressure as it arrives at the pump suctionto 2e sure that the pump selected does not cavitate. 8t is calculated 2ased on system or processconditions. ;7<?a calculation is stated 2elow:;7<?a< hps G hs 6 hvps - hf s4here?ps 7ressure ?ead i.e. 0arometric pressure of the suction vessel converted to head.hs <tatic <uction ?ead i.e. the vertical distance 2etween the eye of first stage impeller centerline and suction liuid level.hvps Iapor pressure ?ead i.e. vapor pressure of liuid at its ma3imum pumpingtemperature converted to ?ead.hf s Frication ?ead i.e. friction and entrance pressure losses on suction side converted to?ead.;ote:

. 8t is important to correct for the specific gravity of the liuid and to convert all terms to units of Tfeeta2soluteT in using the formula.'. Any discussion of ;7<? or cavitation is only concerned a2out the suction side of the pump. ,hereis almost always plenty of pressure on the discharge side of the pump to prevent the fluid fromvapori/ing.

NPSHa in a nutshell 8n a nutshell ;7<? availa2le is defined as:;7<?a 7ressure head G <tatic head - Iapor pressure head of the product - Friction head loss inthe piping valves and fittings. SAll terms in feet a2soluteH8n an e3isting system the ;7<?a can also 2e appro3imated 2y a gauge on the pump suction usingthe formula:

NPSHa = hpS - hvpS hgS + hvS

hpS = Barometric pressure in feet absolute.

hvpS = Vapor pressure of the liquid at maximum pumping temperature, in feet absolute.

hgS = Gauge reading at the pump suction expressed in feet (plus if above atmospheric,minus if below atmospheric) corrected to the pump centerline.

hvS = Velocit head in the suction pipe at the gauge connection, expressed in feet.

Significance of NPSHr and NPSHa,he ;7<? availa2le must always 2e greater than the ;7<? reuir

What care shall be ta3en "hile doin2 layout &or End section < 'op dischar2e ori?ontal type0entri&u2al pump pipin2!ns"er: -,he following point shall 2e ta+en care of while doing layout for "nd section- ,op discharge pumppiping.!. Clear access in 2etween the valve handle and pump shall 2e ensured. ,he valve in suction lineshall 2e installed with the stem in the hori/ontal position i.e. install valve in the vertical run of pipe.B. <uction <trainer shall 2e located at grade to ease easy maintenance and removal for cleaning. ,he



drain connection from strainer assem2ly shall have a 2rea+ up flange immediately after the isolationvalve and the drain line shall 2e routed in such way that the strainer can 2e removed with ease for maintenance.0. Discharge piping shall 2e ta+en to grade for ma+ing valve accessi2le.D. Do not route the suction and discharge piping a2ove prime mover otherwise it may create hindrance

What are the steps in%ol%ed to detect = correct the so&t &oot problem!ns"er:-!. 0efore installation of the machine on the 2ase frame ensure that all mounting pads on the 2aseframe are flat enough. (Chec+ with straight edge across the pads 5 no gap underside of the straightedge.) 8f pad is not flat enough correction can 2e done 2y machining the frame.B. Clean the mounting area 5 install the machine on the 2ase frame.0. Fully tightened all the mounting 2olts. 7lace dial indicator at one of the feet near the 2olthole withstem resting on frame. 1oose all 2olts one 2y one 5 o2serve the dial movement if is not e3ceeding%.%*mm no correction is reuired 5 no soft foot e3ists.D. 8n case of higher movement of dial indicator mar+ the feet. Chec+ the gap 2etween the feet 5mounting pad. 8f there is gap 5 it is uniform then insert shim plate of thic+ness eual to the gap. 8f the gap is not uniform it shall 2e corrected.

What is Blue matchin2 "ith re&erence to the ali2nment o& rotatin2 machinery

!ns"er:-8t is a type of chec+. 0y this method the flatness of the mounting pad is chec+ed. 8n this method 2luecolour (0lue mi3ed with oil) is applied with the help of 2rush on to surface of a glass of suita2le si/e.,he glass with the painted surface pointing towards the mounting pad is place on to the mounting padand is rotated with little pressure. ;ow the glass is removed from the mounting pad. ,he surface of mounting pad which is slightly up is now clearly visi2le as the 2lue colour stic+ on these portions. ;owthese coloured surfaces shall 2e flattened 2y using rotating disc. epeat the a2ove procedure till %Mof the mounting pad surface gets coloured.

What are the 'ools re+uired &or measurin2 the sha&t centre line durin2 ali2nment!ns"er:-Following ,ools are reuired for measuring the shaft centre line.!. <traight edge.

B. Feeler=auge.0. ,aper=auge.D. easuring ,ape 5 uler.E. Alignment 0rac+et.). Iernier caliper.@. Dial 8ndicator.

o" the Dial Indicator readin2 is interpreted 4ention method o& measurement by Dial

indicator!ns"er:-,he inward movement is indicated 2y cloc+wise movement of indicator or in (G) direction. ,he outwardmovement is indicated 2y anti-cloc+wise movement or in (6) direction.Different measurement methods are:-!. Iertical ove : ,he figure shows how the vertical offset of %.%'mm of a shaft with respect tothe other shaft will 2e displayed.B. <weep eading : <weeping reading is o2tained 2y /eroing the dial at the top position on thecoupling to 2e indicated. <lowly rotate the shaft so that the dial indicator isrotated 2y EJ%in %increment. O2tain reading at top (,) 2ottom (0) right ()



and left (1). efer figure.0. ?ori/ontal move : ,he figure () displays how the alignment of two shaft having %.%'mmvertical offset and %.%'mm hori/ontal offset will loo+ ali+e.

4achine ! is 5.57 mm lo"er "ith respect to the machine !

What are the di&&erent ali2nment techni+ues adopted &or ali2nin2 rotatin2 machinery

!ns"er:-Following alignment techniues are adopted for aligning rotating machinery.!. <traight edge 5 feeler gauge ethod.B. <haft alignment using dial indicator.6.5 Face-rim method.6.6 ,wo indicator method.6.7 ,hree indicator method.7.5 everse indicator method.7.6 Face- Face- Distance method.0. 1aser Alignment method.

Describe O)ace-D method usin2 '"o Dial Indicator!ns"er:-

8t is the most widely used method for alignment. 8n this method a 2rac+et is attached to one of the shaftand e3tends near the coupling hu2 on the other shaft. Dial indicators are attached to the 2rac+et withthe stem of one indicator resting on OD or rim of opposite coupling hu2 5 other stem resting on face of same coupling hu2. Offset of the shaft or parallel misalignment is determined 2y the OD readingwhereas angularity is determined 2y QfaceP reading. ;ormally 2oth the shafts are rotated together toeliminate errors due to face and rim irregularities.4achine !4achine B

Write the procedure &or recordin2 the indicator readin2 and its interpretation by '"o indicator method!ns"er:-!. Dial 8ndicator with the pointer indicating /ero to 2e mounted on the 2rac+et f irst.B. otate 2oth the shafts simultaneously in cloc+wise direction.0. ;ote the reading in top 2ottom left and right position of the shaft.D. 8nterpret the final reading and do the reuired adustment.$H$H$$CF85FN('(!DI!/ 5 !>I!/ 5- 5.77 5.5M 5.59 - 5 - 5.65- 5.69 - 5.5MInterpretation: Interpretation:' B G ## ' B G ##' B G - 5.69mm$ ## G - 5.6Amm *o3, ' B G - 5.5Mmm$ ## G - 5.5Hmm *o3,

4achine to be ali2ned ".r.t the stationary 410 is: 4achine to be ali2ned ".r.t the stationary 410 is:!. i2her G - 5.69 5.58 *sa2, G - 5.6617 G 5.5AAmm !. )ace distance is 5.5Mmm "ider.B. ori?ontal &&set: B. ori?ontal @ap:- 5.77- 5.5M *chan2e si2n, G -5.7C17 G - 5.69Amm. 5.59 5.65 *chan2e si2n, G 5.69mmNote: Note:In hori?ontal o&&set$ the total de&lection in Dial In hori?ontal 2ap$ the total de&lection in Dialindicator &rom 5.5M to - 5.77 is -5.66mm.0han2e indicator &rom 5.59 to - 5.65 is 5.69mm.0han2eo& si2n is ust to read the total de&lection only. o& si2n is ust to read the total de&lection only.P;4P



#'!'IN!( 4!0INE4'(4!0INE E/E4EN' 'BE !D;#'ED.

Write the procedure &or recordin2 the indicator readin2 and its interpretation by 'hree indicator method

9F9F99CF85FN('5 INI'I!/ (E!DIN@ - 5.58 5.58 - 5.59 - 5.56 - 5.57)IN!/ (E!DIN@- 5.5A 5 5- 5.59- *- 5.56, G -5.5817 G - 5.56A44 5.58- *-5.57, G - 5.5A17G 5.57A44- 5.5A < *- 5.58, G - 5.5717 G - 5.56

Interpretation:' B G ##' B G - 5.56mm$ ## G - 5.56mm *o3,4achine to be ali2ned ".r.t the stationary 410 is:!. )ace distance is 5.56mm "ider B. ori?ontal @ap: 5.57A 5.56A *chan2e si2n, G 5.59mmNote:In hori?ontal 2ap$ the total de&lection in Dial indicator &rom 5.57A to - 5.56A is 5.59mm.0han2eo& si2n is ust to read the total de&lection only. ere t"o dial indicator is used to note axial readin2.'he &inal axial readin2 is the a%era2e o& the t"o indicator readin2.!>I!/ -6 !>I!/- 7!>I!/

P;4P#'!'IN!( 4!0INE4'(4!0INE E/E4EN' 'BE !D;#'ED.

What is re+uired 2ap clearance &or soc3olet "eldin2 &or thermal expansion!ns"er : 6.A mm to 8.5mm

What is the minimum distance to be maintained bet"een t"o "elds in a pipe!ns"er:'he thumb rule is that the minimum distance bet"een adacent butt "elds is 6D. I& not$ it is ne%er

closer than 6-617R. 'his is supposedly to pre%ent the o%erlap o& !Ss. 4inimum spacin2 o& circum&erential "elds bet"een centerlines shall not be less than 9 times the pipe "all thic3ness or 7A mm "hiche%er is 2reater.

What is the 40 &or #uperheated hi2h pressure #team /ines!ns"er:! 88A @r. P I 1 P 66$ 0omposition: 0r. < T 4o *P6, 1 6U 0r. < T 4o *P66,

What is the normal upstream and do"nstream strai2ht len2th o& ori&ice &lo" meter



!ns"er : ;pstream - 6AD Do"nstream - AD.

D(#'!'I0 'E#' (EQ;I(E4EN'#

4ani&old <Pressure test header o& test e+uipment!ns"er:(e+uirements:

a, 4ani&old shall be calibrated e%ery H months.b, 4ani&old shall be tested 6.7 percent o& re+uired test pressure.

@au2es-!ns"er: Instrument de%ice &or pressure readin2.(e+uirements:

a) Pressure Gauge shall be calbra!e e"er# $ %ee&s'b) All gauges shall have a range such that the test pressure is within 30 to 80% o the ull range!

c) A "ini"u" o two pressure gauges are re#uire$ or the test sste"! &ne pressure gage shall be

on the test "aniol$ an$ the other's) on the test sste"! (heir accurac shall be within % o one

another!

*elie alves -

Answer,

*e#uire"ents,

a) shall be % pressure allowance o the ull range!

b) Saet *elie alve "ust be calibrate ever $as!

Strength (est, A pressure test at an internal pressure $eter"ine$ in accor$ance with this stan$ar$ an$ the

applicable .o$e to veri the integrit o the piping sste"s or service at the $esign

pressure!

*e#uire"ents,

a) (he test pressure shall be increase$ gra$uall until 0% o the strength test pressure has been

reache$!

b) Ater co"pleting visual inspection at 0% o test pressure/ the pressure shall be gra$uall increase$

0% up to 100% o the strength test pressure!

c) (wo hours o total $uration o strength test!

(ightness (est, A pressure test to ensure tightness o the piping sste" 'i!e!/ no lea2s in the sste") at the

test pressure!*e#uire"ent,

a) (he tightness test pressure shall be % o the strength test pressure as per SA4S-5-10/ 6te" 8!3!

b) (he test will be 7 hours e#uipt b te"perature recor$er/pressure recor$er an$ te"perature chart!

c( The )ressure rea*+gs shall be !a&e+ a! ,-./+u!e +!er"als u+!l !he $0

h1ur )er1* has c1/)le!e*'

5a-p -Proce$ure

Answer, 9et 5a-up/ :r 5a-p/ 6nert ;as <5a-p/ A"bient 5a -p



a) 9et la-up - :isplacing the h$rotest water ro" the line ater h$rotest an$ replacing with

appropriatel treate$ la-up water! or wet la-up/ establish an$ "aintain throughout

the sste" a "ini"u" resi$ual o>gen scavenger concentration o 0 pp" in the water

an$ a "a>i"u" o>gen concentration o 10 ppb! (his inclu$es $ea$ legs!

b) :r la-up- inclu$e use o hot $r air/ controlle$ $ew point inert gas/ an$ $ring che"icals such as

glcol or "ethanol applie$ between two pipeline scrapers or as a gelle$ scraper!

c) 6nert ;as 5a-up - :isplace$ the h$rostatic test water b positive pressure with nitrogen or

sweet gas until no water $rains out o the sste"!

$) A"bient 5a-up onl i all o the ollowing con$itions appl

*e#uire"ents,

a!) $rains are available at all low points to ensure co"plete re"oval o water/

b!) corrosion allowance has been provi$e$/

c!) pitting can be tolerate$? an$

$!) particulate rust can be tolerate$!

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