Design of Piping Systems by Tengku Syahdilan

8/17/2019 Design of Piping Systems by Tengku Syahdilan

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Design Of PipingDesign Of Piping

SystemSystem

Prepared by Tengku SyahdilanPrepared by Tengku Syahdilan


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Aim of Seminar Aim of Seminar

To know piping design basics by going throughTo know piping design basics by going throughthe following points:the following points:

Design of pressure components.Design of pressure components.

Pipe Span calculations.Pipe Span calculations. Design of pipe supports & hangers.Design of pipe supports & hangers. Stiffness & flexibility.Stiffness & flexibility.

Expansion & stresses.Expansion & stresses. ine expansion & flexibility.ine expansion & flexibility. Supports & anchorage of piping.Supports & anchorage of piping.


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Design of pressure pipingDesign of pressure piping

!any decisions need be made in the design phase to!any decisions need be made in the design phase toachie"e this successful operation# including:achie"e this successful operation# including:

$ %euired process fluid uantity.$ %euired process fluid uantity.

$ 'ptimum pressure$temperature.$ 'ptimum pressure$temperature.$ Piping material selection.$ Piping material selection.$ (nsulation selection )tracing*.$ (nsulation selection )tracing*.$ Stress & no++le load determination.$ Stress & no++le load determination.$ Pipe support standard.$ Pipe support standard.

The codes pro"ide minimal assistance with any of theseThe codes pro"ide minimal assistance with any of thesedecisions as the codes are not design manuals.decisions as the codes are not design manuals.


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Design of pressure componentsDesign of pressure components Pipe Structure ,static- design# not ayout design.Pipe Structure ,static- design# not ayout design.

imitations: ode# Pressure# Temperature# /ow long is theimitations: ode# Pressure# Temperature# /ow long is theplant lifetime# 0hat is the plant reliability# etc..plant lifetime# 0hat is the plant reliability# etc..

Piping designed according to 123.2 has less lifetime thanPiping designed according to 123.2 has less lifetime than123.3 due to lower 4.S.123.3 due to lower 4.S.

%eliability of piping under 123.3 should be higher than%eliability of piping under 123.3 should be higher than123.2123.2

5i"en that the code is a product of pressure technology#5i"en that the code is a product of pressure technology#one of the concerns is the pressure$temperature ratings ofone of the concerns is the pressure$temperature ratings ofthe components.the components.


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Design of pressure componentsDesign of pressure components Each system be it "essel or piping has some base pressure$Each system be it "essel or piping has some base pressure$

temperature rating. This is essentially the pressuretemperature rating. This is essentially the pressuretemperature rating of the weakest member of the system.temperature rating of the weakest member of the system.This can be translated that no minor component )"al"e#This can be translated that no minor component )"al"e#flange# etc* shall be the weakest link.flange# etc* shall be the weakest link.

The key components of the design conditions are theThe key components of the design conditions are thedesign pressure and the design temperature.design pressure and the design temperature.

Design pressure is defined as the most se"ere sustainedDesign pressure is defined as the most se"ere sustainedpressure which results in the greatest component thicknesspressure which results in the greatest component thickness

and the highest component pressure rating.and the highest component pressure rating.

Design temperature is defined as the sustained pipe metalDesign temperature is defined as the sustained pipe metaltemperature representing the most se"ere conditions oftemperature representing the most se"ere conditions ofcoincident pressure and temperature.coincident pressure and temperature.


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Design of pressure componentsDesign of pressure components

Thus we can try to simplify our stresses into two mainThus we can try to simplify our stresses into two maincategories6categories6

Pressure stress is the circumferential stress )primaryPressure stress is the circumferential stress )primary

stress* or hoop stress# which is known to be not selfstress* or hoop stress# which is known to be not selflimiting.limiting.

Temperature stress is the shear or bending stressTemperature stress is the shear or bending stress)Secondary stress*# known to be self limiting.)Secondary stress*# known to be self limiting.

(n addition(n addition VIBRATION, has to be addressed as low cycleVIBRATION

, has to be addressed as low cyclehigh stress named as “thermal expansion cycles”,h

igh stress named as “thermal expansion cycles”,represented by !" or #$$$ cycles, otherwise detailedr

epresented by !" or #$$$ cycles, otherwise detaileddesign has to be perormed to pro%e that the pipe willdes

ign has to be perormed to pro%e that the pipe willwithstand high cycle, low stress loads&withstand hi

gh cycle, low stress loads&


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Design of pressure componentsDesign of pressure componentsWall Thickness CalculationWall Thickness Calculation

The code assists the designer in determining adeuate pipeThe code assists the designer in determining adeuate pipewall thickness for a gi"en material and design conditions aswall thickness for a gi"en material and design conditions asfollows:follows:

$ alculate the pressure design thickness ,t- $ alculate the pressure design thickness ,t-

$ 7dd the mechanical corrosion and erosion allowances ,c-$ 7dd the mechanical corrosion and erosion allowances ,c-to obtain the thicknessto obtain the thickness

tm8t9ctm8t9c

$ 7dd mill tolerance )!T* to tm# then select the next$ 7dd mill tolerance )!T* to tm# then select the nextcommercially a"ailable wall thickness.commercially a"ailable wall thickness.

$ Pro"ided tD;


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ode Euation:ode Euation:

ttmm 8 PD8 PDoo ;=)SE ;=)SE 9 P>* 9 7 8 t 9 79 P>* 9 7 8 t 9 7

wherewhere::P = Internal esign pressureP = Internal esign pressureDDoo = pipe outsie iameter = pipe outsie iameter

S = the pipe material allowa!le stress" S is for theS = the pipe material allowa!le stress" S is for theliste pipe material at hot temperatureliste pipe material at hot temperature# = $uality factor # = $uality factor % = stress&temperature compensating factor'% = stress&temperature compensating factor'


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TheThe # (ACTO)# (ACTO) is a *allowa!le stress penalty+ !ase on theis a *allowa!le stress penalty+ !ase on themetho of manufacture of the pipe' It is !ase on themetho of manufacture of the pipe' It is !ase on the$uality of the wel in seam&wele pipe an will ha,e a$uality of the wel in seam&wele pipe an will ha,e a,alue ranging from # = -'. for (/)0AC# 1/TT,alue ranging from # = -'. for (/)0AC# 1/TTW#2D#D 3(1W4 to # = 5'- for S#A62#SS PIP#"W#2D#D 3(1W4 to # = 5'- for S#A62#SS PIP#"3S62S4' This (ACTO) is a carry&o,er from the ol ays3S62S4' This (ACTO) is a carry&o,er from the ol ayswhere pipe was manufacture using ri,ets'where pipe was manufacture using ri,ets'

TheThe # (ACTO)# (ACTO) for seam&wele pipe can !e impro,e:for seam&wele pipe can !e impro,e:increasing this factor from -'7 to 5'-'increasing this factor from -'7 to 5'-'

TheThe % (ACTO)% (ACTO) is inclue to account for effects of creepis inclue to account for effects of creepconsiering the non&linear reuction in A22OWA12#consiering the non&linear reuction in A22OWA12#ST)#SS at esign temperatures a!o,e 879 C 3;-- (4'ST)#SS at esign temperatures a!o,e 879 C 3;-- (4'


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Wall thickness pro!lemWall thickness pro!lem::P = 85Pa 385'


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/'S' customary units/'S' customary units::t =7'.9?.--@9357;--?-'7-'8?.--4t =7'.9?.--@9357;--?-'7-'8?.--4

t =-'5; incht =-'5; inch ttmm = -'5; -'-.< -'-8-= -'5; -'-.< -'-8-

ttmm = -'9.9 in= -'9.9 in''3The -'-8 inch ,alue is 59'B mill uner run tolerance of3The -'-8 inch ,alue is 59'B mill uner run tolerance of-'


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Design of pressure componentsDesign of pressure componentsTest PressureTest Pressure

The hydrostatic test pressure at any point in the systemThe hydrostatic test pressure at any point in the systemshould be not less than 3.? times the design pressure.should be not less than 3.? times the design pressure.

4or Temp. abo"e


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EuestionsEuestions

..


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Design of pressure componentsDesign of pressure components6iter 1ens6iter 1ens

''


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Design of pressure componentsDesign of pressure components6iter 1ens6iter 1ens

6iter 1ens ha,e a pressure limitation" as calculate !y e$uations6iter 1ens ha,e a pressure limitation" as calculate !y e$uations38a4" 38!4" or 38c4 of paragraph


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Designers wishing to use miters in a system !ut o not wish to pay thisDesigners wishing to use miters in a system !ut o not wish to pay thispressure penalty can simply increase the wall thickness of the miter"pressure penalty can simply increase the wall thickness of the miter"thus reucing the OOP ST)#SS to ,alues less than the Coethus reucing the OOP ST)#SS to ,alues less than the Coe

limit' This techni$ue seems straight forwar" !ut one $uestionlimit' This techni$ue seems straight forwar" !ut one $uestionremains" where oes the miter startG The coe pro,ies a metho toremains" where oes the miter startG The coe pro,ies a metho toetermine the istance the miter etens into the straight pipe'etermine the istance the miter etens into the straight pipe'

This istance is efine as 6 H


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An eample of 6iter 1en maimum allowa!le internal An eample of 6iter 1en maimum allowa!le internalpressure calculations per paragraph


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6etric units6etric units::S = 55;9.. kPa" # = 5'-" T = ;' &5'9 = 7'< mm"S = 55;9.. kPa" # = 5'-" T = ;' &5'9 = 7'< mm"r r 99 = -'3;58'8&;'4 = 89' mm" then= -'3;58'8&;'4 = 89' mm" then::

PPmm =355;9..?'7@89'4 ? '7@H'7-'.8


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0et test e$uation 83!4 with0et test e$uation 83!4 with JJ = 99'L= 99'LPPmm=S#3T&c4@r =S#3T&c4@r 99? )? )55&r &r 99@3)@3)55&-'r &-'r 99446etric units6etric units:: PPmm=55;9..'7@89' ? 35


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1' (or a miter fa!ricate using1' (or a miter fa!ricate using JJ=


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Design of pressure componentsDesign of pressure components1ranch Connection1ranch Connection


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1ranch Connections1ranch Connections1ranch connections are mae in piping systems !y any one of se,eral1ranch connections are mae in piping systems !y any one of se,eral

methos' These coul !e tees" pa reinforce or unreinforcemethos' These coul !e tees" pa reinforce or unreinforceintersections" crosses" integrally reinforce wel&on or wel&inintersections" crosses" integrally reinforce wel&on or wel&in

contoure insert fittings" or etrusions' H


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The amount of re$uire pressure reinforcement is etermine !yThe amount of re$uire pressure reinforcement is etermine !yperforming A)#A )#P2AC#6#0T CA2C/2ATIO0S using theperforming A)#A )#P2AC#6#0T CA2C/2ATIO0S using theesign conitions esta!lishe for the intersection' Area replacementesign conitions esta!lishe for the intersection' Area replacementcalculations are not re$uire for intersections using 2IST#D&)AT#Dcalculations are not re$uire for intersections using 2IST#D&)AT#D

or 2IST#D&/0)AT#D T## I0T#)S#CTIO0S pro,ie theor 2IST#D&/0)AT#D T## I0T#)S#CTIO0S pro,ie theintersection is use within the pressure&temperature !ouns stateintersection is use within the pressure&temperature !ouns statein the 2ISTI0N STA0DA)D' Area )eplacement calculations are notin the 2ISTI0N STA0DA)D' Area )eplacement calculations are notre$uire for /02IST#D T## I0T#)S#CTIO0S pro,ie the teere$uire for /02IST#D T## I0T#)S#CTIO0S pro,ie the teecomponent has successfully complete the re$uirements ofcomponent has successfully complete the re$uirements ofparagraph


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The branch & run angle between A? and B@ deg. 7nd theThe branch & run angle between A? and B@ deg. 7nd theaxes intersect.axes intersect.

The principle is that the area remo"ed by the opening isThe principle is that the area remo"ed by the opening isadded or accounted for as added reinforcement or excessadded or accounted for as added reinforcement or excess

area due to thickness abo"e the pressure reuirements.area due to thickness abo"e the pressure reuirements.

d3 8 effecti"e length remo"ed from the run at the branch#d3 8 effecti"e length remo"ed from the run at the branch#d3 8 Db or d3 8 CDb $ )Tb$c* ; sind3 8 Db or d3 8 CDb $ )Tb$c* ; sin

d= 8 3;= the width of reinforcement +oned= 8 3;= the width of reinforcement +one

d= 8 greater of d3 or C )Tb F c* 9)Th F c* 9d3;= # butd= 8 greater of d3 or C )Tb F c* 9)Th F c* 9d3;= # butless than Dhless than Dh


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A8 height of reinforcement +one 8 smaller ofA8 height of reinforcement +one 8 smaller of=.?)Tb F c*9Tr and =.? )Th F c*=.?)Tb F c*9Tr and =.? )Th F c*

Dh: 'utside diameter of headerDh: 'utside diameter of header Db: 'utside diameter of branchDb: 'utside diameter of branch

th: header pressure design thicknessth: header pressure design thickness tb: branch pressure design thicknesstb: branch pressure design thickness

Th: header thickness minimum per purchase or minus millTh: header thickness minimum per purchase or minus milltolerancetolerance

Th: nominal wall thickness of headerTh: nominal wall thickness of header

Tb: branch thickness minimum per purchase or minus millTb: branch thickness minimum per purchase or minus milltolerancetoleranceTb: nominal wall thickness of branchTb: nominal wall thickness of branch


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Tr: thickness of reinforcement padTr: thickness of reinforcement pad

c: sum of mechanical )thread & groo"e*# corrosion and erosionc: sum of mechanical )thread & groo"e*# corrosion and erosionallowancesallowances

: angle between the header and the branch axes: angle between the header and the branch axes

%euired area 73 8 th.d3.)= $ sin%euired area 73 8 th.d3.)= $ sin **

7=: excess area in run 8)= d= $ d3* )Th F th $ c*7=: excess area in run 8)= d= $ d3* )Th F th $ c*

72: excess area in branch 8 =.A )Tb Ftb F c* ; sin72: excess area in branch 8 =.A )Tb Ftb F c* ; sin

7A: area pro"ided by weld & area of reinforcement pad7A: area pro"ided by weld & area of reinforcement pad

7=9 72 9 7A7=9 72 9 7A GG 7373


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Area replacement rules of 1< 5'< are ,ali for !ranch connections meeting Area replacement rules of 1< 5'< are ,ali for !ranch connections meetingthe following conitionsthe following conitions::

54 the run pipe iameter to thickness ratio 3D54 the run pipe iameter to thickness ratio 3D hh@T@Thh4 is less than 5-- an the4 is less than 5-- an the

!ranch to run iameter ratio 3D!ranch to run iameter ratio 3D!!@D@Dhh4 is not greater than 5'-'4 is not greater than 5'-'

9494 for run pipe with 3Dfor run pipe with 3Dhh@T@Thh4 Q5--4 Q5-- the !ranch iameter D! is less that one&the !ranch iameter D! is less that one&half the run iameter Dhalf the run iameter Dhh''


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The re$uire percent replace area within the prescri!e reinforcingThe re$uire percent replace area within the prescri!e reinforcing!ounaries epens on the angle of the intersection' This percent!ounaries epens on the angle of the intersection' This percentre$uire area will range from 5--B of the area remo,e"re$uire area will range from 5--B of the area remo,e"

th'5'39 & sinth'5'39 & sin RR4"4"for a ;- intersection to a!out 5


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An eample of the area replacement rules" consier the following two An eample of the area replacement rules" consier the following two;-- intersections" the first is an;-- intersections" the first is an UNREINFORCED FABRICATEDUNREINFORCED FABRICATEDTEE TEE " the secon is a" the secon is a PAD REINFORCED FABRICATED TEE PAD REINFORCED FABRICATED TEE " 3see" 3see

(igure 58'-4' 1oth intersections are the same pipe sies an ha,e(igure 58'-4' 1oth intersections are the same pipe sies an ha,ethe same esign conitions'the same esign conitions'

(in the replace area in the /0)#I0(O)C#D (A1)ICAT#D T## for(in the replace area in the /0)#I0(O)C#D (A1)ICAT#D T## forthe conitionsthe conitions::

)un pipe: D0 9-- 0om' Wall 7'9 mm 30PS 7 Sch 8-4 AST6 A< Nr1')un pipe: D0 9-- 0om' Wall 7'9 mm 30PS 7 Sch 8-4 AST6 A< Nr1'1ranch pipe: D0 5-- 0om' Wall .'- mm 30PS 8 Sch 8- AST6 A< Nr1ranch pipe: D0 5-- 0om' Wall .'- mm 30PS 8 Sch 8- AST6 A< Nr

1 S62S1 S62SP = 85


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#ample#ample A" metric area replacement calculation for an intersection A" metric area replacement calculation for an intersection::D0 9--" P = 7'9 mm D0 5--" T = .'- mm" /0)#I0(O)C#D (A1)ICAT#DD0 9--" P = 7'9 mm D0 5--" T = .'- mm" /0)#I0(O)C#D (A1)ICAT#D

T##T##''

I' 0omenclatureI' 0omenclature' 3)eference (IN'


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The pressure esign thickness for the heaer an !ranch pipes" usingThe pressure esign thickness for the heaer an !ranch pipes" usinge$uation 3


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#ample#ample A intersection is not suita!le for pressure esign' Consiering A intersection is not suita!le for pressure esign' Consieringthe percent replace area is only a!out


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#ample#ample 1" metric" intersection: D0 9--" th=7'9 0om' wall D0 5--"1" metric" intersection: D0 9--" th=7'9 0om' wall D0 5--"t!=.'- mm 0om' wall" ;-- PAD )#I0(O)C#D I0T#)S#CTIO0" Pat!=.'- mm 0om' wall" ;-- PAD )#I0(O)C#D I0T#)S#CTIO0" Paimensions: Timensions: Tr r = 7'9mm" ia = 9-


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The pressure esign thickness for heaer an !ranch pipes" calculate !yThe pressure esign thickness for heaer an !ranch pipes" calculate !ye$uation 3


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EuestionsEuestions

1%E7H1%E7H

I II I

JJ

KK


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Pipe SupportingPipe Supporting


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Pipe SupportingPipe Supporting

The obLecti"e during the pipe supports designThe obLecti"e during the pipe supports designphase is to pre"ent the following:phase is to pre"ent the following:

M o"erstress of pipingo"erstress of piping

M leakage at Lointsleakage at LointsM o"erstress of supportso"erstress of supports

M excessi"e forces on euipmentexcessi"e forces on euipment

M excessi"e interference with thermal expansionexcessi"e interference with thermal expansion

M excessi"e pipe sag )especially for piping reuiring drain*excessi"e pipe sag )especially for piping reuiring drain*

M excessi"e heat flow# exposing support to temperatureexcessi"e heat flow# exposing support to temperatureoutside their limitsoutside their limits

M Etc..Etc..


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Pipe SupportingPipe Supporting The purpose of pipe supports is to control the weight effects of theThe purpose of pipe supports is to control the weight effects of the

piping system" as well as loas cause !y pressure thrust" ,i!ration"piping system" as well as loas cause !y pressure thrust" ,i!ration"win" earth$uake" shock" an thermal isplacement' The weightwin" earth$uake" shock" an thermal isplacement' The weighteffects to !e consiere shall !e the greater of operating or hyro&effects to !e consiere shall !e the greater of operating or hyro&test loastest loas''

The 1< 5'< guiance for pipe support types an materials ofThe 1< 5'< guiance for pipe support types an materials ofconstruction is presente in the 1


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Pipe Supporting & SpanPipe Supporting & Span

Pipe Support Span, based on deflectionPipe Support Span, based on deflection

Pipe support span is a ecision that faces the esigner in most pipe supportingPipe support span is a ecision that faces the esigner in most pipe supporting o!s' As a guie to the selection of support spacing" the following e$uation o!s' As a guie to the selection of support spacing" the following e$uation!ase on permissi!le mi span eflection is offere!ase on permissi!le mi span eflection is offere''

The permissi!le mi&span eflection" y" concept is one techni$ue commonlyThe permissi!le mi&span eflection" y" concept is one techni$ue commonly

selecte for support spacing' This techni$ue is !ase on a specifie mi&selecte for support spacing' This techni$ue is !ase on a specifie mi&span" y eflection of the supporte pipe consiering the pipe" contents" anspan" y eflection of the supporte pipe consiering the pipe" contents" aninsulation weights' The e$uation isinsulation weights' The e$uation is::

2= Hy'#'I @ 99''W2= Hy'#'I @ 99''WXX

wherewhere::

2 = pipe support spacing" feet"2 = pipe support spacing" feet"y = permissi!le mi&span eflection" inchesy = permissi!le mi&span eflection" inches# = moulus of elasticity at esign temperature" l!@in 3TA12# C&.# = moulus of elasticity at esign temperature" l!@in 3TA12# C&.33I = moment of inertia of pipeI = moment of inertia of pipe''W = weight of supporte pipe" incluing pipe" contents" insulation" l!@ftW = weight of supporte pipe" incluing pipe" contents" insulation" l!@ft''


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Pipe Support Span, based on stressPipe Support Span, based on stress

As a guie to the selection of support spacing" the following e$uation As a guie to the selection of support spacing" the following e$uation!ase on permissi!le stress is offere!ase on permissi!le stress is offere''

The permissi!le mi&span eflection" y" concept is one techni$ueThe permissi!le mi&span eflection" y" concept is one techni$ue

commonly selecte for support spacing' This techni$ue is !ase oncommonly selecte for support spacing' This techni$ue is !ase onstress of supporte pipe material consiering the pipe" contents"stress of supporte pipe material consiering the pipe" contents"an insulation weights' The e$uation isan insulation weights' The e$uation is::

2= H-'


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An eample of the eflection pipe span approach is An eample of the eflection pipe span approach is::What is the span of a seamless AST6 A5-. Nrae 1" .'.9 inch OD" -'97 inch wallWhat is the span of a seamless AST6 A5-. Nrae 1" .'.9 inch OD" -'97 inch wall

thick" water fille pipe with < inch of insulation with a esign temperature of 8-- (Gthick" water fille pipe with < inch of insulation with a esign temperature of 8-- (GThe specifications limit the mi&span eflection to -'9 inchThe specifications limit the mi&span eflection to -'9 inch''

SolutionSolution::

Determine the uniform loa" pouns per footDetermine the uniform loa" pouns per foot''Pipe = 5;'- l!s per ftPipe = 5;'- l!s per ftWater = 59' l!s per ftWater = 59' l!s per ftInsulation = M'. l!s per ft 3 7 B 6agnesia Calcium Silicate4Insulation = M'. l!s per ft 3 7 B 6agnesia Calcium Silicate4then "W =


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Pipe Supporting & DrainagePipe Supporting & Drainage

DrainageDrainage

Piping systems shoul !e installe to rain !y gra,ity" in irection ofPiping systems shoul !e installe to rain !y gra,ity" in irection ofnormal flow'normal flow'

#ach span must !e pitche so that the outlet will !e lower than the#ach span must !e pitche so that the outlet will !e lower than the

maimum sag of the pipe'maimum sag of the pipe'The pitch of pipe spans is the ratio !etween the rop in ele,ation anThe pitch of pipe spans is the ratio !etween the rop in ele,ation anthe length of span' It is calle the a,erage graient an is epressethe length of span' It is calle the a,erage graient an is epressein inches per foot or mm per meter run'in inches per foot or mm per meter run'

Nraient check for rainageUNraient check for rainageU

N = rop in ele,ation @ span 3in@ft'4N = rop in ele,ation @ span 3in@ft'4

While" conition for goo rainageUWhile" conition for goo rainageUN [ 83maimum eflection4 @ spanN [ 83maimum eflection4 @ span


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EuestionsEuestions


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Pipe Supports \ angersPipe Supports \ angers Support Selection & DesignSupport Selection & Design

M Selection and design of pipe hangers is an important part of theSelection and design of pipe hangers is an important part of theengineering study. /igh temperature# high pressure pipes are critical toengineering study. /igh temperature# high pressure pipes are critical toa point that early in the basic design phase supports locations and loadsa point that early in the basic design phase supports locations and loadsha"e to be decided upon. oncentrated hanger loads on structures#ha"e to be decided upon. oncentrated hanger loads on structures#buildings and their effect on euipment ha"e to be well known from thebuildings and their effect on euipment ha"e to be well known from the"ery beginning of the proLect."ery beginning of the proLect.

M 1asic information has to collected before proceeding with calculations1asic information has to collected before proceeding with calculationsand detailing of pipe supports# as follows6and detailing of pipe supports# as follows6$ 7 complete set of piping drawings$ 7 complete set of piping drawings$ 7 complete set of steel and structural drawings; data.$ 7 complete set of steel and structural drawings; data.$ 7 complete set of drawings showing locations of "entilating ducts#$ 7 complete set of drawings showing locations of "entilating ducts#electrical cable trays# euipment locations )pumps# tanks# etc*electrical cable trays# euipment locations )pumps# tanks# etc*

$ 7 complete set of piping specifications and data.$ 7 complete set of piping specifications and data.$ (nsulation specification.$ (nsulation specification.$ !o"ement of all critical euipment connections such as boiler headers#$ !o"ement of all critical euipment connections such as boiler headers#steam drums# turbine connections# etc..steam drums# turbine connections# etc..$ The results of stress# flexibility# and mo"ement calculations performed$ The results of stress# flexibility# and mo"ement calculations performedfor critical systems.for critical systems.


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Pipe Supports \ angersPipe Supports \ angers

7pplying the pre"iously mentioned basic info shall be in the following7pplying the pre"iously mentioned basic info shall be in the followingsteps6steps6$ The determination of hanger locations.$ The determination of hanger locations.$ Determination of the thermal mo"ement of the piping at each$ Determination of the thermal mo"ement of the piping at eachhanger location.hanger location.$ The calculation of hanger loads.$ The calculation of hanger loads.

$ The selection of hanger types# spring assembly# either constant$ The selection of hanger types# spring assembly# either constantsupport type# "ariable support or rigid support type.support type# "ariable support or rigid support type.$ hecking of clearances between the hanger components and$ hecking of clearances between the hanger components andnearby piping# electrical cable trays# conduits# "entilating ducts#nearby piping# electrical cable trays# conduits# "entilating ducts#euipment# etc.euipment# etc.

%ecogni+ing that each new piping design presents an abundance of%ecogni+ing that each new piping design presents an abundance ofnew problems to the engineer# no attempt is made to state fixednew problems to the engineer# no attempt is made to state fixedrules and limits which would be applicable to e"ery hanger design#rules and limits which would be applicable to e"ery hanger design#only guidance to ideas to sol"e simple practical support problems.only guidance to ideas to sol"e simple practical support problems.


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Support DesignSupport Design

M %estraints )anchors and guides* are pro"ided to direct%estraints )anchors and guides* are pro"ided to directthermal expansion to areas designed to absorb it and tothermal expansion to areas designed to absorb it and to

ensure that expansion Loint mo"ements occur in theensure that expansion Loint mo"ements occur in thedirections for which the Loint is designed. Expansiondirections for which the Loint is designed. Expansion Loint design shall conform to the reuirements of Loint design shall conform to the reuirements of7ppendix N# which pro"ides guidelines for the design#7ppendix N# which pro"ides guidelines for the design#fabrication and installation of bellow type expansionfabrication and installation of bellow type expansion Loints. Loints.

M SupportsO elements shall be designed for all loadsSupportsO elements shall be designed for all loadsapplied including weight# pressure# wind# earthuakes#applied including weight# pressure# wind# earthuakes#friction etcfriction etc


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M Spring supports are designed to carry theSpring supports are designed to carry theweight loads and pre"ent misalignment#weight loads and pre"ent misalignment#buckling# eccentric loading and unintentionalbuckling# eccentric loading and unintentional

disengagement of the load. Spring supportsdisengagement of the load. Spring supportsshould be pro"ided with position indicators.should be pro"ided with position indicators.

M onstant supports of the counterweight andonstant supports of the counterweight and

hydraulic types should be pro"ided with safetyhydraulic types should be pro"ided with safetyde"ices and stops.de"ices and stops.


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M (ntegral attachments such as plugs# ears# shoes# plates#(ntegral attachments such as plugs# ears# shoes# plates#etc# are designed to minimi+e locali+ed stresses# stressetc# are designed to minimi+e locali+ed stresses# stressconcentration in cyclic ser"ice and any harmfulconcentration in cyclic ser"ice and any harmfultemperature gradient. The material should be of goodtemperature gradient. The material should be of gooduality and all reuirements of the ode for welding#uality and all reuirements of the ode for welding#

preheating and post$weld heat treatment should apply.preheating and post$weld heat treatment should apply.%einforcement by pad and complete encirclement%einforcement by pad and complete encirclementreinforcement shall be used to distribute stresses andreinforcement shall be used to distribute stresses andreduce heat effect in alloy piping.reduce heat effect in alloy piping.

M Qon$integral attachments include clamps# R$bolts#Qon$integral attachments include clamps# R$bolts#

cradles# saddles# straps# cle"ises. 4or "ertical pipecradles# saddles# straps# cle"ises. 4or "ertical pipeweight support# the clamp should be located below aweight support# the clamp should be located below aflange or fitting or a welded lug.flange or fitting or a welded lug.


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angers #ampleangers #ample


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angers #ample" 6o,ementangers #ample" 6o,ement


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angers #ampleangers #ample


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angers #ample" 6o,ementangers #ample" 6o,ement


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anger Supportsanger Supports


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)o anger Assem!ly)o anger Assem!ly


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)o anger Assem!ly)o anger Assem!ly

The pipe attachment and the structural beamThe pipe attachment and the structural beam

attachment of a rod hanger assembly shouldattachment of a rod hanger assembly shouldallow the hanger to swing to allow for lateralallow the hanger to swing to allow for lateralmo"ement of the pipe where there is hori+ontalmo"ement of the pipe where there is hori+ontalpipe expansion. (t should be noted that hori+ontalpipe expansion. (t should be noted that hori+ontalmo"ement of the hanger will result in a "erticalmo"ement of the hanger will result in a "erticalmo"ement as shown pre"ious slide. Themo"ement as shown pre"ious slide. Thesubseuent hori+ontal forces should be checked.subseuent hori+ontal forces should be checked.


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Varia!le anger Assem!lyVaria!le anger Assem!ly


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Varia!le anger SupportsVaria!le anger Supports

ariable spring hangers are recommended for general use in nonariable spring hangers are recommended for general use in noncritical piping and where "ertical mo"ement is small on criticalcritical piping and where "ertical mo"ement is small on criticalpiping.piping.

7cceptable practice is limit amount of supporting force "ariation7cceptable practice is limit amount of supporting force "ariation

)difference between hot load and as installed$cold load* to =?)difference between hot load and as installed$cold load* to =?for critical piping systems on hori+ontal piping.for critical piping systems on hori+ontal piping.

The amount of "ariation can be calculated by multiplying theThe amount of "ariation can be calculated by multiplying thespring scale in lb;inch )Hg;mm* by the amount of "erticalspring scale in lb;inch )Hg;mm* by the amount of "erticalexpansion in inches )mm*.expansion in inches )mm*.

The main problem with "ariable spring hangers is that thisThe main problem with "ariable spring hangers is that this"ariation in load must go somewhere# it is transferred to the"ariation in load must go somewhere# it is transferred to thenearest restraint or euipment which may cause damage both tonearest restraint or euipment which may cause damage both tothe euipment and; or piping system.the euipment and; or piping system.


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Varia!le anger SupportsVaria!le anger Supports alculating the "ariability in accordance with !SS SP$?U:alculating the "ariability in accordance with !SS SP$?U:

ar. 8 )/ot load F old load*;/ot load x 3@@ar. 8 )/ot load F old load*;/ot load x 3@@

The load margin between the maximum load# either hot orThe load margin between the maximum load# either hot or

cold# and the load at the maximum limit of the operatingcold# and the load at the maximum limit of the operatingrange must also be considered. This load margin should berange must also be considered. This load margin should begreater than the weight of the hanger hardware that isgreater than the weight of the hanger hardware that issupported by the spring# ex. lamps and hanger rods usedsupported by the spring# ex. lamps and hanger rods usedto connect the piping to the spring. (f the total piping loadsto connect the piping to the spring. (f the total piping loadsplus the load of the supported hanger hardware cannot beplus the load of the supported hanger hardware cannot beaccommodated within the spring hangers operating rangeaccommodated within the spring hangers operating rangean alternate spring hanger design should be considered.an alternate spring hanger design should be considered.


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Constant 2oa SupportConstant 2oa Support

onstant support hangers pro"ide constant supporting force for pipingonstant support hangers pro"ide constant supporting force for pipingthroughout its full range of "ertical expansion and contraction.throughout its full range of "ertical expansion and contraction.


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Spring angersSpring angers


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Spring angers #ampleSpring angers #ample %eturning back to our Example:%eturning back to our Example:

Difference in effect in using a "ariable spring as compared to aDifference in effect in using a "ariable spring as compared to aconstant spring support hanger# as per 4ig. /$3# page 3?V.constant spring support hanger# as per 4ig. /$3# page 3?V.

oad for /anger /$3 was calculated as ?2


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Selection of Pipe supportingSelection of Pipe supportingDe,icesDe,ices

Piping Systems: Temperature classification.Piping Systems: Temperature classification.Piping systems# are di"ided into the three main temperature categoriesPiping systems# are di"ided into the three main temperature categories

in order to pro"ide a basis for the selection of hangers# anchors# orin order to pro"ide a basis for the selection of hangers# anchors# orsupports.supports.

3. /ot systems3. /ot systems

a.a. The temperature range is from 3=@4 )?@* to A?@4 )=2@*. TypicalThe temperature range is from 3=@4 )?@* to A?@4 )=2@*. Typicalexamples are low$pressure steam# hot water and certain processexamples are low$pressure steam# hot water and certain processpiping.piping.

b.b. The temperature range is from A?@4 )=2@* to


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=. 7mbient systems in which the contents of the pipe are not=. 7mbient systems in which the contents of the pipe are notheated or cooled by mechanical means. Temperaturesheated or cooled by mechanical means. Temperatureswould range up to 3=@ 4. Plant air and ser"ice water wouldwould range up to 3=@ 4. Plant air and ser"ice water wouldbe typical systemsbe typical systems

2. old systems2. old systemsa.a. The temperatures range upward from 2= 4. 7 typicalThe temperatures range upward from 2= 4. 7 typical

example would be chilled water pipingexample would be chilled water pipingb.b. The temperature ranges downward from 2= to minus =@4#The temperature ranges downward from 2= to minus =@4#

as in brine systemsas in brine systemsc.c. 1elow minus =@ 4# as in cryogenic systems1elow minus =@ 4# as in cryogenic systems

Selection of Pipe supportingSelection of Pipe supporting


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..



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Pipe 7ttachments. /angers for the "arious systems described abo"ePipe 7ttachments. /angers for the "arious systems described abo"emay be selected from fig.33 in accordance with the followingmay be selected from fig.33 in accordance with the followingrecommendations:recommendations:

4or Type 3a systems# hangers Types 3 and 2 through 3= are used.4or Type 3a systems# hangers Types 3 and 2 through 3= are used.

%ollers should be types A3 through AV with appropriate saddles of%ollers should be types A3 through AV with appropriate saddles ofType 2B# items 3 and =. Supports would be Types 2? through 2U.Type 2B# items 3 and =. Supports would be Types 2? through 2U.

4or Type 3b systems# hangers Types 3# 2# A and U are used. %ollers4or Type 3b systems# hangers Types 3# 2# A and U are used. %ollersshould be types A3 through AV with appropriate saddles of Typeshould be types A3 through AV with appropriate saddles of Type2B# items 3 and =.2B# items 3 and =.

4or Type 3c systems# alloy hangers are used as reuired by the line4or Type 3c systems# alloy hangers are used as reuired by the linetemperature. /angers should be of Types =# 2# or U with saddlestemperature. /angers should be of Types =# 2# or U with saddlesof Type 2B# items 3 or =# and the rollers of Types A3 through AVof Type 2B# items 3 or =# and the rollers of Types A3 through AV



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4or Type = systems# hangers can be of Types 3 and 2 through 3= with4or Type = systems# hangers can be of Types 3 and 2 through 3= withsupports of Types =A# =


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Spring supports6Spring supports6 4or systems which operate at temperatures below V?@4# a4or systems which operate at temperatures below V?@4# a

good rule is that the "ariation in supporting force be limitedgood rule is that the "ariation in supporting force be limitedto =? of the load. 0hen the suggestions are followed forto =? of the load. 0hen the suggestions are followed forstress limits set forth in !SS SP$?U# para 33# and 7ST!stress limits set forth in !SS SP$?U# para 33# and 7ST!specification 73=?# springs to suit specific conditions mayspecification 73=?# springs to suit specific conditions maybe designed.be designed.

/owe"er# the price of a specially designed spring includes/owe"er# the price of a specially designed spring includesengineering and setup charges# and unless a large uantityengineering and setup charges# and unless a large uantityof a particular si+e is to used# it is not economical to designof a particular si+e is to used# it is not economical to designspecial indi"idual springs# and a more prudent approach isspecial indi"idual springs# and a more prudent approach isto select spring de"ices which are a"ailable commercially.to select spring de"ices which are a"ailable commercially.



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ibration arising from pump pulse# compressor and similaribration arising from pump pulse# compressor and similarconditions is a problem in piping systems. Such conditions can beconditions is a problem in piping systems. Such conditions can bea"oided by use of commercially a"ailable spring supports. Systemsa"oided by use of commercially a"ailable spring supports. Systemsthat respond to exciting "ibrations can be controlled satisfactorilythat respond to exciting "ibrations can be controlled satisfactorilyby the use of dampening de"ice. There are two general types toby the use of dampening de"ice. There are two general types toconsider6 the coiled spring and the hydraulic "ibration dampener.consider6 the coiled spring and the hydraulic "ibration dampener.

There are two types of coiled$spring "ibration dampeners6 theThere are two types of coiled$spring "ibration dampeners6 theopposed$spring type and the double acting spring type )type?@*.opposed$spring type and the double acting spring type )type?@*.These types should be arranged so that the springs are in theThese types should be arranged so that the springs are in theneutral position during normal operating conditions of the system.neutral position during normal operating conditions of the system.

The hydraulic "ibration control is a unit which operates by meansThe hydraulic "ibration control is a unit which operates by meansof a controlled flow of fluid through an orifice. %esistance toof a controlled flow of fluid through an orifice. %esistance tomo"ement increases with the speed of displacement. 'ne distinctmo"ement increases with the speed of displacement. 'ne distinctad"antage of the hydraulic de"ice is that there is a min. ofad"antage of the hydraulic de"ice is that there is a min. ofresistance to thermal mo"ement of the piping.resistance to thermal mo"ement of the piping.

1oth spring and hydraulic cylinder de"ices may be used to control1oth spring and hydraulic cylinder de"ices may be used to controlsway and absorb shocks.sway and absorb shocks.



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/anger %od6/anger %od6 %od used for pipe support purposes is usually hot rolled%od used for pipe support purposes is usually hot rolled

steel with cut threads conforming to Qational 1ureau ofsteel with cut threads conforming to Qational 1ureau ofStandards /andbook /$= lass =7# for the coarse threadStandards /andbook /$= lass =7# for the coarse threadseries. %olled threads to the same standard may be used.series. %olled threads to the same standard may be used.(t must be pointed out that the length of a rolled thread(t must be pointed out that the length of a rolled threadcannot be increased by running a die o"er it# since thecannot be increased by running a die o"er it# since thebasic diameter of the rod is less than the si+e of thebasic diameter of the rod is less than the si+e of thethreaded portion.threaded portion.

Safe load capacities of rods are based on the area at theSafe load capacities of rods are based on the area at theroot of the thread. 7 generally accepted standard for suchroot of the thread. 7 generally accepted standard for such

capacities is gi"en in table ?# taken from !SS SP$?U.capacities is gi"en in table ?# taken from !SS SP$?U.



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..


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7nchors and restraints may be reuired to establish definite7nchors and restraints may be reuired to establish definitemo"ement patterns# counteract thrust forces# or# as in the case ofmo"ement patterns# counteract thrust forces# or# as in the case of"ibration$imposing euipment used to pre"ent transmittal and"ibration$imposing euipment used to pre"ent transmittal andpossible build$up of "ibration throughout the entire system. Specificpossible build$up of "ibration throughout the entire system. Specificexamples are the need for properly located anchors in a steamexamples are the need for properly located anchors in a steamdistribution system to pre"ent o"erloading of the smaller branches#distribution system to pre"ent o"erloading of the smaller branches#anchors and guides# to actuate and align expansion Loints and loopsanchors and guides# to actuate and align expansion Loints and loops

properly# and restraints of fixed points in the "icinity of compressorproperly# and restraints of fixed points in the "icinity of compressoreuipment or uick$closing control "al"es. ong straight runs oreuipment or uick$closing control "al"es. ong straight runs orsections of piping that are ob"iously weak in some plane may reuiresections of piping that are ob"iously weak in some plane may reuireadditional guiding or bracing to pro"ide lateral structure stability.additional guiding or bracing to pro"ide lateral structure stability.

7s in the case of all applications of anchors and guides# the o"erall7s in the case of all applications of anchors and guides# the o"erallinstallation must pro"ide sufficient flexibility to accommodate thermalinstallation must pro"ide sufficient flexibility to accommodate thermal

growth. 4or sections where the mo"ement does not permit the use ofgrowth. 4or sections where the mo"ement does not permit the use ofrigid struts# guides with sufficient clearance to accommodate therigid struts# guides with sufficient clearance to accommodate thenormal mo"ement may suffice by limiting the displacement. Positi"enormal mo"ement may suffice by limiting the displacement. Positi"estrut action can be obtained at points subLect to mo"ement throughstrut action can be obtained at points subLect to mo"ement throughthe use of special de"ices such as hydraulic snubbers.the use of special de"ices such as hydraulic snubbers.



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%isers are eui"alent to concentrated loads6 howe"er# in the%isers are eui"alent to concentrated loads6 howe"er# in thesupport of the load# se"eral important points must besupport of the load# se"eral important points must beconsidered. These are:considered. These are:

3.3. (s the support to take the entire riser weight# or is this weight(s the support to take the entire riser weight# or is this weight

to be distributed among se"eral supportsWto be distributed among se"eral supportsW=.=. 7re the hydrostatic$test conditions more se"ere than ser"ice7re the hydrostatic$test conditions more se"ere than ser"ice

conditions6 that is6 will the cold$water$filled condition imposeconditions6 that is6 will the cold$water$filled condition imposestresses on the support higher than allowable )in coldstresses on the support higher than allowable )in coldcondition* as compared with hot operating condition and thecondition* as compared with hot operating condition and theimposed stressesW 0hen this decision is made# the systemimposed stressesW 0hen this decision is made# the system

erection seuence should be considered and a determinationerection seuence should be considered and a determinationmade whether other supports are effecti"e or ineffecti"e duringmade whether other supports are effecti"e or ineffecti"e duringhydrostatic testing.hydrostatic testing.



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2. (s the support to be located at a point of +ero "ertical2. (s the support to be located at a point of +ero "erticalmo"ement and hence to be considered a rigid supportW (f thismo"ement and hence to be considered a rigid supportW (f thisis the case# then the hori+ontal and flexural mo"ements mustis the case# then the hori+ontal and flexural mo"ements mustbe analy+ed. Pure hori+ontal mo"ement can be pro"ided forbe analy+ed. Pure hori+ontal mo"ement can be pro"ided for

long support rods which are allowed to swing. /owe"er# iflong support rods which are allowed to swing. /owe"er# ifflexural mo"ement exists# it may cause tipping# and then mustflexural mo"ement exists# it may cause tipping# and then mustbe assumed that the entire load can transfer to one supportbe assumed that the entire load can transfer to one supportrod. (n this case# the riser support must be designed for doublerod. (n this case# the riser support must be designed for doublethe calculated load.the calculated load.

N SN i S t


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Nuie SupportsNuie Supports

N i SN i S t


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Nuie SupportsNuie Supports

2i it t S t2i it t S t


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2imit stop Supports2imit stop Supports

S t ( i tiS t ( i ti


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Supports (rictionSupports (riction

) t i t S t) t i t S t


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)estraint Supports)estraint Supports

2i it t S t2i it t S t


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2imit stop Supports2imit stop Supports

Pi ) k S tPi ) k S t


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Pipe )ack SupportsPipe )ack Supports

1)#A>1)#A>


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1)#A>1)#A>

XREST('QSXREST('QS

I II I

JJ

KK

Stiff \ (l i!ilitStiff \ (l i!ilit


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Stiffness \ (lei!ilityStiffness \ (lei!ility

Prismatic member# straight members of uniform crossPrismatic member# straight members of uniform crosssectional area. They are the building blocks of structuralsectional area. They are the building blocks of structuralengineering and also piping software packages. 7ssumingengineering and also piping software packages. 7ssumingthat the displacements are small# so that shortening of thethat the displacements are small# so that shortening of thebeam due to bending# may be ignored.beam due to bending# may be ignored.

Each member has itOs own ,local- axis which do not coincideEach member has itOs own ,local- axis which do not coincidewith the axis for other members of the structure. (t is thuswith the axis for other members of the structure. (t is thusassumed that a force applied in any one principal planeassumed that a force applied in any one principal planecauses displacements in that plane only and that the shearcauses displacements in that plane only and that the shearcentre coincides with the centroid of the member.centre coincides with the centroid of the member.

There is a possibility of three linear displacements and threeThere is a possibility of three linear displacements and threerotations at each end of the member. There are thus 3=rotations at each end of the member. There are thus 3=possible displacement components for each member# or 3=possible displacement components for each member# or 3=degrees of freedom. 7ssociated with each displacementdegrees of freedom. 7ssociated with each displacementthere is a corresponding force or moment.there is a corresponding force or moment.

Stiff \ (l i!ilitStiff \ (l i!ilit


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The result of the deri"ation section can be summari+ed in a singleThe result of the deri"ation section can be summari+ed in a singlematrix euation for member stiffness as follows6matrix euation for member stiffness as follows6

C4 8 CH CNC4 8 CH CN This is the member stiffness euation# 4 & N are 3=$term "ectors ofThis is the member stiffness euation# 4 & N are 3=$term "ectors of

member force and displacement respecti"ely# and k is a 3=x3=member force and displacement respecti"ely# and k is a 3=x3=

member stiffness matrix. This is the stiffness matrix for the mostmember stiffness matrix. This is the stiffness matrix for the mostgeneral case of a prismatic member in space neglecting shear andgeneral case of a prismatic member in space neglecting shear andwith the implicit condition that the deformations are so small as towith the implicit condition that the deformations are so small as tolea"e the basic geometry unchanged.lea"e the basic geometry unchanged.

Qot all structural members reuire the full 3= degrees of freedomQot all structural members reuire the full 3= degrees of freedomto express their deformations. Since a member in space can ha"eto express their deformations. Since a member in space can ha"e

no moments transmitted to it through itOs hinged ends# itOsno moments transmitted to it through itOs hinged ends# itOsdeformation depends only on the three linear displacements atdeformation depends only on the three linear displacements ateach end# gi"ing it a total of six degrees of freedom.each end# gi"ing it a total of six degrees of freedom.

(t is important to note the symmetry of the member stiffness(t is important to note the symmetry of the member stiffnessmatrix k.matrix k.

Stiff \ (l i!ilitStiffness \ (le i!ilit


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Transformation of axis6Transformation of axis6The system of axis for a prismatic member is a local axis system.The system of axis for a prismatic member is a local axis system.

The x$axis is defined as coinciding with the centroidal line of theThe x$axis is defined as coinciding with the centroidal line of themember. (n a structure with many members there would thus bemember. (n a structure with many members there would thus beas many systems of axes. 1efore the internal actions in theas many systems of axes. 1efore the internal actions in themembers of the structure can be related# all forces and deflectionsmembers of the structure can be related# all forces and deflectionscan be stated in terms of one single system of axes common to allcan be stated in terms of one single system of axes common to all

the F structure ,global- axes.the F structure ,global- axes.

The directional cosines matrix can therefore be thought of as the 2x2The directional cosines matrix can therefore be thought of as the 2x2rotation matrix %o. Thus any uantity can be redefined in terms ofrotation matrix %o. Thus any uantity can be redefined in terms ofglobal axes by pre$multiplying by the rotation matrix. 0hen usedglobal axes by pre$multiplying by the rotation matrix. 0hen usedto redefine member forces and deflections in structure axes# thisto redefine member forces and deflections in structure axes# thisprocess is con"entionally referred to as transformation of axes#process is con"entionally referred to as transformation of axes#and the symbol T is used for the transformation matrix.and the symbol T is used for the transformation matrix.

T 8 C%o @ T 8 C%o @ C@ %oC@ %o

Stiff \ (l i!ilitStiffness \ (lei!ility


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1asic reuirements:1asic reuirements:

Piping systems shall ha"e sufficient flexibility to pre"entPiping systems shall ha"e sufficient flexibility to pre"ent

thermal expansion or contraction or mo"ements of pipingthermal expansion or contraction or mo"ements of pipingsupports at terminals from causing6supports at terminals from causing6$ 4ailure of piping or supports from o"erstress or fatigue4ailure of piping or supports from o"erstress or fatigue$ eakage at Loints.eakage at Loints.$ Detrimental stresses or distortion in piping and "al"es or inDetrimental stresses or distortion in piping and "al"es or in

connected euipment )pumps and turbines for example*#connected euipment )pumps and turbines for example*#

resulting from excessi"e thrusts and moments in theresulting from excessi"e thrusts and moments in thepiping.piping.

Stiff \ (l i!ilitStiffness \ (lei!ility


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Specific reuirements:Specific reuirements:

(n brief they are#(n brief they are#

$ The computed stress range at any point due toThe computed stress range at any point due todisplacements in the system shall not exceed the allowabledisplacements in the system shall not exceed the allowablestress range.stress range.

$ %eaction forces computed shall not be detrimental to%eaction forces computed shall not be detrimental tosupports or connected euipment.supports or connected euipment.

$ omputed mo"ement of the piping shall be within anyomputed mo"ement of the piping shall be within anyprescribed limits# and properly accounted for in theprescribed limits# and properly accounted for in theflexibility calculations.flexibility calculations.



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Stiffness \ (lei!ilityStiffness \ (lei!ility oncepts:oncepts:

Displacement strains6Displacement strains6Thermal displacements# Piping system will undergo dimensionalThermal displacements# Piping system will undergo dimensional

changes with any change in temperature. (f constrained fromchanges with any change in temperature. (f constrained fromfree expansion or contraction by connected euipment andfree expansion or contraction by connected euipment andrestraints such as guides and anchors# it will be displaced fromrestraints such as guides and anchors# it will be displaced fromits unrestrained position.its unrestrained position.

%estraint flexibility# where restraints are not considered rigid# their%estraint flexibility# where restraints are not considered rigid# theirflexibility may be considered in determining displacement stressflexibility may be considered in determining displacement stressrange and reactions.range and reactions.

Externally imposed displacements# externally caused mo"ement ofExternally imposed displacements# externally caused mo"ement ofrestraints will impose displacements on the piping in addition torestraints will impose displacements on the piping in addition tothose related to thermal effects. !o"ements may result fromthose related to thermal effects. !o"ements may result from

tidal changes )dock piping*# wind sway )eg. Piping supportedtidal changes )dock piping*# wind sway )eg. Piping supportedfrom a tall slender tower*# or temperature changes in connectedfrom a tall slender tower*# or temperature changes in connectedeuipment.euipment.

Total Displacement strains# Thermal displacements# reactionTotal Displacement strains# Thermal displacements# reactiondisplacements# and externally imposed displacements all ha"edisplacements# and externally imposed displacements all ha"eeui"alent effects on the piping system# and shall be consideredeui"alent effects on the piping system# and shall be considered

together in determining the total displacement strains.together in determining the total displacement strains.



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oncepts# cont.:oncepts# cont.:Displacement stresses6Displacement stresses6Elastic beha"ior# stresses may be considered proportional to theElastic beha"ior# stresses may be considered proportional to the

total displacement strains in a piping system in which the strainstotal displacement strains in a piping system in which the strainsare well distributed and not excessi"e at any point )a balancedare well distributed and not excessi"e at any point )a balancedsystem*. ayout of systems should aim for such a condition.system*. ayout of systems should aim for such a condition.

'"erstrained beha"ior# stresses can not be considered proportional'"erstrained beha"ior# stresses can not be considered proportionalto displacement strains throughout a piping system in which anto displacement strains throughout a piping system in which anexcessi"e amount of strain may occur in locali+ed portions of theexcessi"e amount of strain may occur in locali+ed portions of thesystem )an unbalanced system*# unbalance may result from onesystem )an unbalanced system*# unbalance may result from oneor more of the following6or more of the following6$$ highly stressed small si+e pipe runs in series with large orhighly stressed small si+e pipe runs in series with large or

relati"ely stiff pipe runs.relati"ely stiff pipe runs.$$ a local reduction in si+e or wall thickness# or local use ofa local reduction in si+e or wall thickness# or local use ofmaterial ha"ing reduced yield strength.material ha"ing reduced yield strength.$$ a line configuration in a system of uniform si+e in which thea line configuration in a system of uniform si+e in which theexpansion or contraction must be absorbed largely in a shortexpansion or contraction must be absorbed largely in a shortoffset from the maLor portion of the run.offset from the maLor portion of the run.

EuestionsEuestions


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EuestionsEuestions

#pansion \ Stresses#pansion \ Stresses


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Effect of expansion and stresses within a piping system needEffect of expansion and stresses within a piping system needto be determined by knowing the following6to be determined by knowing the following6

0hich code that applies to system.0hich code that applies to system.

Design Temperature and Pressure.Design Temperature and Pressure. !aterial Specification.!aterial Specification. Pipe Si+e & wall thickness of each of the pipingPipe Si+e & wall thickness of each of the piping

components.components. The layout of the system including dimensions andThe layout of the system including dimensions and

thermal mo"ement of terminal points.thermal mo"ement of terminal points. imitations of end reactions on terminal points as gi"enimitations of end reactions on terminal points as gi"en

by euipment manufacturers.by euipment manufacturers.



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The reuirements for formal analysis are identicalThe reuirements for formal analysis are identicalto those of 123.3. The ode gi"es the followingto those of 123.3. The ode gi"es the followingeuation )same as 123.3* to check if formaleuation )same as 123.3* to check if formal)simplified or comprehensi"e* analysis is reuired:)simplified or comprehensi"e* analysis is reuired:

D y ; ) F R *D y ; ) F R *== Y @.@2Y @.@2

M D: outside pipe diameter# mmD: outside pipe diameter# mmM y : resultant of displacement strain# mmy : resultant of displacement strain# mm

M : de"eloped length# m: de"eloped length# mM R: anchor straight distance# length of straight line LoiningR: anchor straight distance# length of straight line Loining

anchors# manchors# m



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7pplicable code only will determine the minimum safety7pplicable code only will determine the minimum safetyreuirements for the material at the design conditions ofreuirements for the material at the design conditions ofpressure and temperature.pressure and temperature.

Some code specify the modulii of elasticity for commonlySome code specify the modulii of elasticity for commonlyused piping materials as well as formulae to determineused piping materials as well as formulae to determinestress intensification factors and flexibility factors.stress intensification factors and flexibility factors.

odes state that# the piping system shall be treated asodes state that# the piping system shall be treated aswhole# in calculating the flexibility of a piping systemwhole# in calculating the flexibility of a piping systembetween anchor points and that the significance of allbetween anchor points and that the significance of allparts shall be recogni+ed.parts shall be recogni+ed.

(n addition# calculations shall take into account stress(n addition# calculations shall take into account stressintensification factors which apply to components otherintensification factors which apply to components otherthan sections of straight pipe.than sections of straight pipe.



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#pansion \ Stresses#pansion \ StressesThe analysis of piping loaded by pressure# weight and thermalThe analysis of piping loaded by pressure# weight and thermal

expansion so the analyst needs to understand the application ofexpansion so the analyst needs to understand the application ofthe Principal 7xis system# to simplify.the Principal 7xis system# to simplify.

onsider a cube remo"ed from a stressed section of pipe.onsider a cube remo"ed from a stressed section of pipe.alculate the stress in the cube and compare it to some allowablealculate the stress in the cube and compare it to some allowablestress limit.stress limit.

ST%ESS is ratio of 4'%E to 7%E7 or !'!EQTS D((DED 1> P(PEST%ESS is ratio of 4'%E to 7%E7 or !'!EQTS D((DED 1> P(PESET('Q !'DRRS.SET('Q !'DRRS.

Each force acting on the cube# can be trigonometrically reducedEach force acting on the cube# can be trigonometrically reducedto force components# represented by "ectors# acting along eachto force components# represented by "ectors# acting along each

of the principal axis. The resultant of the component of eachof the principal axis. The resultant of the component of eachforce acting on the face of the cube# di"ided by the area of theforce acting on the face of the cube# di"ided by the area of thecube face is called the P%(Q(P7 ST%ESS. The principal stresscube face is called the P%(Q(P7 ST%ESS. The principal stressthat act along the centerline of the pipe is called athat act along the centerline of the pipe is called a'Q5(TRD(Q7 P%(Q(P7 ST%ESS. This stress is caused by'Q5(TRD(Q7 P%(Q(P7 ST%ESS. This stress is caused bylongitudinal bending# axial force loading or by pressurelongitudinal bending# axial force loading or by pressure..



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%7D(7 P%(Q(P7 ST%ESS# acts on a line from the center of pipe%7D(7 P%(Q(P7 ST%ESS# acts on a line from the center of piperadially through the pipe wall. This stress is a compressi"e stressradially through the pipe wall. This stress is a compressi"e stressacting on the pipe (D caused by internal pressure# or a tensile stressacting on the pipe (D caused by internal pressure# or a tensile stresscaused by external or "acuum pressurecaused by external or "acuum pressure..

(%R!4E%EQT(7 P%(Q(P7 ST%ESS# sometimes called /''P or(%R!4E%EQT(7 P%(Q(P7 ST%ESS# sometimes called /''P orT7Q5EQT(7 ST%ESS acts on a line perpendicular to theT7Q5EQT(7 ST%ESS acts on a line perpendicular to the'Q5(TRD(Q7 and the %7D(7 ST%ESS. This stress attempts to'Q5(TRD(Q7 and the %7D(7 ST%ESS. This stress attempts toseparate the pipe wall in the circumferential direction. This stress isseparate the pipe wall in the circumferential direction. This stress iscaused by internal pressurecaused by internal pressure..

0hen two or more P%(Q(P7 ST%ESSES act at a point on a pipe# a0hen two or more P%(Q(P7 ST%ESSES act at a point on a pipe# aS/E7% ST%ESS will be generated. 'ne example of a S/E7% ST%ESSS/E7% ST%ESS will be generated. 'ne example of a S/E7% ST%ESSwould be at a pipe support where a %7D(7 ST%ESS caused by thewould be at a pipe support where a %7D(7 ST%ESS caused by thesupporting member acts in combination with the 'Q5(TRD(Q7supporting member acts in combination with the 'Q5(TRD(Q71EQD(Q5 caused by the pipe o"erhang1EQD(Q5 caused by the pipe o"erhang..



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7llowable Stress %ange7llowable Stress %ange12 3.2 establishes a maximum allowable stress range that can12 3.2 establishes a maximum allowable stress range that canbe safely accommodated by a piping system before failure willbe safely accommodated by a piping system before failure willcommence for two separate stress loading conditions. Thesecommence for two separate stress loading conditions. Theselimits are for stress le"els that canlimits are for stress le"els that can##

3.*3.* cause failure from a single loading# andcause failure from a single loading# and##=.*=.* cause failure from repeated cyclic loadingscause failure from repeated cyclic loadings..

The 7'071E ST%ESS %7Q5E# S7 C 2@=.2.?)d* is theThe 7'071E ST%ESS %7Q5E# S7 C 2@=.2.?)d* is thestress limit for the =nd stress le"el# those stresses that arestress limit for the =nd stress le"el# those stresses that are

repeated and cyclic in nature# or simply# it is the allowable forrepeated and cyclic in nature# or simply# it is the allowable forthe SE'QD7%> ST%ESS# the D(SP7E!EQT ST%ESS %7Q5E.the SE'QD7%> ST%ESS# the D(SP7E!EQT ST%ESS %7Q5E.

123.2 presents two euations for the calculation of S7123.2 presents two euations for the calculation of S7..



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#pansion \ Stresses#pansion \ StressesEuation 3a is as follows6Euation 3a is as follows6

S7 8f)3.=? Sc9@.=?Sh*S7 8f)3.=? Sc9@.=?Sh*

and euation 3b is as followsand euation 3b is as follows##S7 8fC3.=?)Sc9Sh*$SS7 8fC3.=?)Sc9Sh*$S

Sc and Sh are the basic allowable stresses for the cold and hotSc and Sh are the basic allowable stresses for the cold and hotconditions as defined in Section 3.2.A. Sc and Sh "alues areconditions as defined in Section 3.2.A. Sc and Sh "alues arefound in 123.2 7ppendix 7 T71E 7$3found in 123.2 7ppendix 7 T71E 7$3..

f is the ST%ESS$%7Q5E %EDRT('Q 47T'%6f is the ST%ESS$%7Q5E %EDRT('Q 47T'%6

this factor can be selected from the table shown below or canthis factor can be selected from the table shown below or canbe calculated by euation of 123.2 asbe calculated by euation of 123.2 as::

f8


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MThe S term is the 'Q5(TRD(Q7 ST%ESSES to be discussedThe S term is the 'Q5(TRD(Q7 ST%ESSES to be discussedlaterlater..

M7lthough euations are both the allowable stress# S7# for the7lthough euations are both the allowable stress# S7# for thecalculated thermal displacement stress range# SE# eachcalculated thermal displacement stress range# SE# each

euation has a specific application.euation has a specific application.

MEuation 3a is a system allowable stress of the entire pipingEuation 3a is a system allowable stress of the entire pipingsystem of the same material# thermal cycles# andsystem of the same material# thermal cycles# andtemperature6temperature6

Mwhile euation 3b is a component allowable stress# S7# forwhile euation 3b is a component allowable stress# S7# foreach single component in the piping system where S haseach single component in the piping system where S hasbeen calculated for that component under analysisbeen calculated for that component under analysis..



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ppCol SpringingCol Springing

old springing is the intentional deformation ofold springing is the intentional deformation ofpiping during assembly to lower the initialpiping during assembly to lower the initialdisplacement strains in the operating condition.displacement strains in the operating condition.

(t is used to lower the forces transmitted to(t is used to lower the forces transmitted toconnected euipment and to lower the de"iationconnected euipment and to lower the de"iationfrom as$installed dimensions# such as inclinationfrom as$installed dimensions# such as inclinationof hangers. /owe"er# cold springing does notof hangers. /owe"er# cold springing does notchange the magnitude of stress range.change the magnitude of stress range.

The amount of cold spring -.S.- is usuallyThe amount of cold spring -.S.- is usuallyexpressed as a percentage or fraction of the totalexpressed as a percentage or fraction of the totalexpansion Zexpansion Z



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The 1


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ayout of piping system should pro"ide inherentayout of piping system should pro"ide inherentflexibility# howe"er# for the cases where theflexibility# howe"er# for the cases where the

system lacks flexibility the designer shouldsystem lacks flexibility the designer shouldconsider increasing flexibility by means of bends#consider increasing flexibility by means of bends#loops# offsets# swi"el Loints# bellow or slip typeloops# offsets# swi"el Loints# bellow or slip typeexpansion Loints.expansion Loints.



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This center$of$gra"ity;line$of$thrust concept is furtherThis center$of$gra"ity;line$of$thrust concept is furtherillustrated by the following two computer analysis of theillustrated by the following two computer analysis of theabo"e pipe layouts.abo"e pipe layouts.

1oth piping layouts are the same pipe si+e# temperature#1oth piping layouts are the same pipe si+e# temperature#and the anchors are the same distance apart.and the anchors are the same distance apart.

The shape layout has a maximum expansion stress ofThe shape layout has a maximum expansion stress of=A#A?? psi.=A#A?? psi.

The [ shaped has A=#?BA psi.The [ shaped has A=#?BA psi.

The shape mo"ed the center of gra"ity# cg away from theThe shape mo"ed the center of gra"ity# cg away from theline of thrust which produced a lower stress# greaterline of thrust which produced a lower stress# greaterflexibility e"en though the [ shape had one more elbowflexibility e"en though the [ shape had one more elbow..

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Design of Piping Systems by Tengku Syahdilan