Introduction To Pipe Stress Analysis - Sam Kannappan [PDF]

Zitiervorschau

Sam Kannappan, P.E. Engineer Tennessee Valley Authority Knoxville. Tennessee

A WILEY-INTERSCIENCE PUBLICATION New York

.

JOHN W LEY & SONS Chichester

Brisbane

Toronto

Singapore

PE STRESS Sam Kannappan, P.E. Enginear Tennessee b l l e p Authoris), KnoxviBIeo Tennessee

A VVrLEV-INTERSCIENCE PUBLlCATlObV

JOHN WELEV dtlr SONS Mew Vork

e

Chichesler

rn

Brlsbane

a

Toronto

.

Singapore

PREFACE

Copyright @ 1986 by John Wiley dt Sons. Inc All rights rexrved. Publiskd simultaneously in Canada,

Reprduction or translation of any part of this work k y o n d that permitted by Section 107 or 108 of 8he 1976 United States Copright Act witbut the pemission of the copright owner is unlsvvful. Requests lor pmission or further information skould be x:ddrcssed to the Pemissions Department, John Wiley 61 Sons, Inc.

Llbnrr). of Coegnss C ~ ~ ~ l q lInr rPPbgielrrrlcn g hca: Kannappen, Sam. Iniroduclion to pipf stress analysis. "A Wiley-intenciente publicaiio~."

Until 1967 piping design was p d o r m e d primarily using ruie-of-thumb layout design procedures and p r e a n a l ~ e dpiping 1ayr.ut data in tabular form. The publication of ANSI E131.1-1667 Power Piibing Code and the availability of analysis computer programs have intrduced cost-eflective piping design. The objective of this book is to present a practical appmacl" to analylica! piping design. It is intended to be used by engineers in the industry and students interested in piping design. Knowledge of applied mechanics and strength of materials is a must for understanding this b k . The text contains many illustrations, code equations, tables, and examples. Work$d out example problems are included to assist the reader in undersfanding the principles discussed in each chapter. Exercises and references are given at the end of each chapter. Piping analysis lopics, such as support stilifness, overrapping, decoupiing of branch lines, wind loads, arsd other advanced topics, are covered in another book entitled Advanced Pip S~ressAnalysis by the same author and publisher. il am indebted to many organizations, including the Amellican Ssiery of Mechanical Engineers and the Expansion Joint ManufacturesqAssmiation, lor granting permission to reproduce design, tables, and graphs. 1 thank all my friends and the members of my own family, my wife Meena, sons Rsmesh, Narayanan, Ram, daughter Abirami, and my brother S. Narayanan, lor their support lor me in writing this h k .

fncludes index. I . Pip lines--&sign and construction 2. Strains and stresses. I. Title.

Knoxville, Tennessee Decembcr B Y8.B Pdntrd In the United States of h e r i c r I098165432 1

CONTENTS

Farces and Moments on a Piping System 1 Static and Dynamic Loads 4 Piping Specification 7 Explenation of Terms Welaled to Pipa S u p p s ~ s11 The Guided Cantilever Method 12 Comparison of Simplified Analysis Methods 14

2 DESIGN OF PRESSURE CQIVlPQNEWS Calculation of Minimum Wall Thickness of a Pipe 22 ~eihforcementsfor Welded Branch Connections 29

3 PIPE SPAN CALCUUTION Span Limitations 34 Neturel Frequency 35 Drainage 37 Guide, Spacing far Wind Loading 46 Design Rules for Pipa Sarpporls 47 4 ANSI PIPING CODES ARD ASME CODES

intarnel Pressure and Longitudinal Stresses W Petroleum Rslinsy Piping Code Requirements for Formal Ansbsis 53 lnplane and Butplans Bending Moments 55 Stress Inben~iCif~ t i n nC ~ r * v - " 6

am

"

ENecl of Pressure o n Stress Intensification and Flexibilihl Factors 66 Stresses in a Piping System 72 Cold Spring 76

5 EXPANSION LQOPS AND EXPAlUSlON JOlNTS

(..> Design Loads and Sewice Limits 171 Flexibiliv and Stress Intensification Factors 171 Analysis l o r Class 2 Piping Stress Evaluation 882 Naturat Frequency 183 Piping Systems t o Be Ansiyzed 183 Useful Mints In Piping Design 185

82

Expansion Loops 82 Stresses and Loads in Loops 85 Expamion Joints 92 Types of Expansion Joints 95 Pressure Thrust Force 96

Computer Modeling 186 lnitial Anchor and Supporl Movements 187 Modeling of Piping Ebmenrs 190

BVomenelature 102 EMarnsl Moments I82 Comparison of Allowable and Actual Moments 103

7 PlPlNG CONNECTED TO NONROTATlNG EQUIPMEM

10S

Local Stress Calculation Using WRC 107 Bulletin 109 Rotational Spring Rate for Cylindrical Vessel 118 8 PlPlNG CONNECTED TO ROTATlNG EQUIPMENT

E Br

t

Piping Gsnnected t o Piping Connected t o Piping Connected t o Piping Yield Method

Stetem Turbines 123 Centrifugal Compressors 128 Centrifugal Pumps 128 130

VsSves 132 Analysis lor Reaction Forces Due ta V a k e Discharge 136 Aluminum Pipine) 139 Copper Alloy Pipe 141 Underground Piping 1@ EHernal Pressure Design 155 Vessels Under External Pressure 158 Jacketed Prsssurs Piping System 160 Metric Units 165 Malsrlel Behavior at Elevated Temperature 165 Refrecloy Lining 167

123

Al. A2. A3. A4. A5.

Total Thermal Expansion for Metals 202 Modulus of Elasticin/ l o r Metals 218 Allswablet Stresses in Tansion far Materials 212 Propefiies and W e i g h of Pipe 226 Sample Calculations for Branch Reinforcement 236

CHAPTER O N E

PIPE STRESS ANALYSIS

k i p stress analysis provides the necessaay technique lor engineers to design piping systems without overstressing and oversoading the piping compnents and connected equipment. The Following terms from applied mechanics are: hrlcf(y tliscussed (not defined) here to familiarize tdle engineer with them.

FORGES AND MQMEIVBS QFd A POPING SYSTEM FORCE: The force is a vector quantity with the direction and magnitude of the push (compression), pull (tension), or shear eFTects. M C D M F NMonlenl ~: is a vector quantity with the direction and magnitude at twisting and bending eflecls. I

I

Forces and moments acting on the piping system due lo diWerent t y v s of loadings, such as thermal expansion and dead weight, will Re discussed taler in detail. Stress is the farce ger unit area. This change in length divided by the original length is called strain.

Stress-%GrainCurve for Ductile and Nsn&ctlla Material For a ductile material, suck as ASTM A53 Grade B, the stress-strain curve is given in Figure 1. I . Until the proportions! limit is reached, variation al stress in the material with respect lo strain follows a straight line, Hmke" law slope as Young's modulus of elasticity E. Ulrimire tensile s -qc

i I

tb

p

1s

'q'

.-

*

1.

-

A list of common piping meterials under severe cyclic conditions is given next (reference I):

JrC

Pipe for Severe C y c l k CorodNons

Only the following pipe* shall be used under severe cyclic conditions: (a) Carbon Steel Pipe

Allotvable (temperature < 105°F)

Allowable ltemperalure at 800°F)

FIGURE 1.1 Twical siress-strain curve for ductile material (ASTM A53 Graie B).

the curve at which any further strain will cause permanent deformations to stressed elernenas. Allowable stress is the yield strength divided by factor of safety.

A typica! stress-strain curve for a nonductile material like cast irtln is g S e n in Figure l . 2 The stress-strain diagram lor a given piping material shows the limitations on stress to avoid permanent deformation or rupture.

,

API 5L, Seamless API 51,, SAW, Factor ( E ) 0.95 or greater AP1 5LX 42, Seamless APl 5LX 46, Seamless APl 5LX 52, Seamless ASTM A53, Seamless ASTM A 106 ASTM A333, Seamless ASTM A369 ASTM A38 1, Factor ( E ) 0.90 or greater ASTM A524 ASTM A67 1, Facror ( E ) 0.90 or greater ASTM A672, Factor ( E l 0.91) or greater ASTM A69 1 , Facror ( E ) O.Yi) or greater (h) Low and Infermediare Alloy Sfeel P i p

A333, Seamless A335 A369 A426, Facror ( E ) 0.W or ASTM A67 1, Faclor (E) 0.90 or ASTM A672, Factor ( E ) 0.90 or ASTM A69 1, Factor (E) 0.90 or

ASTM ASTM ASTM ASTM

(c)

greater greater greater greater

Sfainless Sfeel Alloy Pipe

ASTM A248, Seamless ASTM A3 12, Seamless RGURE B*2 Tplcrl strewtrain curve lor noductile matedal (csst iron).

* From ANSllASMB B31 t .J, Section 305.23, 1980 edition

i

~ ~ S A358, T M Factor (El 0.90 or greater AS'kM A376 I ASTM A430 ASTM A451, Factor ( E l 0.90 or greater

Coppr and Copper Alloy P i p

(64)

ASTM 842

1

,

ASTM ASTM AS'TM ASTM

Bldl 58 165 8167 B4Q7

ASTM B2 10, Tempers O and Mi 1 12 ASTM 8 2 14, Tempers O and H 112

FOB I

meckanica! properties and chemical composition ol each one of the a b v e materials, see ASTM standards (reference 2). Special piping materials include inconel, hastclloy, zirconium, and aluminum alloys. Selection of a specific material depends upon the process temperature and its corrosion properties. Sizing of the piping depends upon volume flow with minimum Bow friction (reference 8).

STATIC AND DYNAMIC LOADS Lpadings aResting the piping system can be classified as primary and secondary. Primary loading occurs from sustained loads like dead weight. Primary loads are called non-self limiting loads. An example of a secondary loading (sell limiting) is a thermal expansion load. Because dillerent piping codes define the piping qualification criteria in slightly di6Verent way, each code will be addressed separately later. Static Loadings include:

I. 2. 3. 4.

Vibration. Discharge loads.

Nickel Alloy P i p

AIurningtm Allay P i p

tf)

I , impact forces. 2. Wind. 3. Seismic loads (earthquake). 4. 5.

ASTM B466

(el M c k e l and

Live loads under weigh! ePlecl include weigh8 of content, snow, and ice: loads Dead loads consist ot weight of piping valves, flanges, Insulation, and oihe~ superimpsed permanent loads. Dynamic loadings include:

Weight eBect (live loads and dead laad%). Thermal expansion and cnnrrereth cRcccs. Effects of s u p p r l , I M ~ a, d terminal mvcflrcnts Internal or external premure hading.

'I'hemrul eflacts include thermal loads that arise when free thermal expansion or eonrracrion is prevented by supports or anchors, loads due to temperature gradients in thick pipe walls, and loads due Ica diaerence iao thermal coefficients of materials as in jacketed piping. The coefiienr of linear expansion of a solid is defined as the increment of length in ;a unit length for a change in temperature of one degree. The unit is microinches pe"i"eh per "F. 'I'he unit for the mean coefficient of thermal expansion between 7(3"F (installation temperature) and the given temprature is given as inches of expansion per 100 Ft of pipe length in Table A % of Appendix (va9raes are Bar~ns ASME 83 1.3 Piping Code]. To convert from incklinchFF to inch1100 It, thc lr~llowingrelation may be used:

Expansion coeficient (in./ l OHD lt) = (coeficient) x

L 2 x LOO (design temp. - installation temp.] (1.11

Young's modulus or modulus a! elasriciry E is unit stress divided by unit strain. For most structural materials the modulus of elasticity for compression is the same as for tension. Value of E decreases with an increase in temperature. Table A2 of Appendix gives E values for piping materials for the normal temperature range. The ratio of unit lateral contraction to unit axial elongalion Is called Poisson's rado. Codes allow a value of 0.3 Is be used at all temperatures lor all metals. S P E C I ~ IGRAVITY: C The specific gravity of a solid or liquid is the ratio of the mass of an equal volume of water s t some standard remprature (physicists use 39°F and engineers use 60°F). The specific gravity of gases is usually expressed in terms of hydrogen and air; i t Is a raurnkr without a unit. DENS! TY: The density p Is the mass

I

8:

LdleLe1.1

4

p a b e * , ilatio sod D e d t y Density ($b/ih.')

Material T m

hot modulus E;k is prmifted in eaBculating forces and moments at the equipment nozzles. However, the higher value (at 70°F or at installation temperature) should be used in stress calculations.

Piping Msterlalr

Poisson's Ratio

0.283

Cashn steel with 0 ~ 3 %carh~onor Dess Austeniaie steels (SS) Inttrmediimte alloy steel 5% Cr Mcp--9%Cr Ma Bra= 166% Cw344"o Zn) Aluminum alloys

PIPING SPEGIFBGATIQN

0.288

0.283

Piping svcification is written for each service such as steam, sir, oxygen, and caustic. The specification contains information a b u t piping material, thickness, recommended valves, Ranges, branch connection, and instrument connection. Figure 1.3 shows a spcificalion far caustic service.

0.316 0.100

S ~ e c ~ ~WEIG~OT: iic The specific weight (LI is the weight per unit volume. ' n ~ einterrelation of density and specific weight is w = gp, where g is

a~celerariondue to gravity. Tablc I . I gives values of Poissonvs ratio and density lor common piping

material. Example

1, Fi sd tEIe linear thermal expansion (in./ 100 It) between 7 0 and 392°F for c'airboo steel. CwRcient for 375°F = 2.48 in./lO(lft (values from Apwndix Table At). CwRcient lor 4W5F 2.70 in./100 I r Differcoke p r degree in expansion = (2.7 - 2.48)/25 = 0.0088 By lit~earinterplation, expansion lor

-

;

An 8 in, pipe needs a pipe with thickness of 80 schedule (which allows for allowance and maximum internal pressure of 2W psig up to 150°F) with a kvel-edged AS3 Grade B seamless. The g i o k vaive used is crane 35 1 d (reference 1 in Chapter 3). The flanges are oF 150 psi pressure rating with raised face and weld neck slip on t y v . The marerial of the fiange is A-1[)5 ( p r standard ANSI B16.5). The requirement for the branch connection (here weldolet or tee) is given on the branch connection table. For an 8 in. header and a 3 in. branch, the weldoler is required for given internal pressure. The pressure and temperature conditions in the pipeline should always be within (inside the hatched line) the pressure-tem~ralcaee curve given in the specificalion.

4 in. corrosion

Piping systems should have suacient Bexibiliry so that thermal expansion or contraction or movements of supports and terminal points will not cause:

2. Find the modulus of elasticity lor austenilic steel at (a) -2fHPF. (b) 70F, and (c) 625'F, E at 2 W F Z 29.9 X 106psi (read From Appendix Table A2) E at 7VF: = 28.3 .X 10""psi E for 625°F shouid be interpolated &tween values of 600°F and "I05F

E for 625°F i s

25.4

- 25((25,4 - 24.8)f 1001 = 25.4 - 0. i 5 = 25.25 x

10' psi

Note the8 the E value decreases with increase in temperature. Lower values of Young's modulus means that the Rexibility is higher. Use of

Failure of piping or support from overstress or fatigue. 2. Leakage at joints. 3. Detrimental stresses or distortion in piping or in connected equipment (pumps, vessels, or valves, For example) resulting from excessive thrusts or moments in the piping. 1.

Flexibility denotes the measurement of the presence ol necessary piping length in the proper direction. The p u r p s e of piping flexibility analysis is to pmdduce a piping layout that causes neither excessive stresses nor excessive end reactions. To achieve this, layout should not be stifle lr is also not desirable lo make the system unnecessarily flexible because this requires excess materials, thus increasing initial cost. More length with many bends increase$ nrecqrlrc. dron t ~ ~ h i r h -. ;**#

-

i~ncs3 In. and larger 3 4 rn

4CRD rap lnstr. )DO pu mrrrd lace weld rcfck oPilice

bdu wrh ZA-194 GR2 -t( heavy k x . nun. Noce I C.rlceu: iL,m. l P b e O I ~ l steel stud

full face

b2 in. ud l u g e .

ws: . . Wr kmgtleo a d e n g n per ANSI 816.5 rt8. 7 . Ulc: reAon upc lor s n d con**

k n g e w11h r r e w d tap

L ~ n n2 in. a& k ~ g c r

Pkrr aarsrr ~ n e i y ~ ~ a Flexible pfping Expsnsicn joint

lFfGURE 1.6 Piping with expansion joint. RGURE 1.4

FIexible and sliB piping

Figtjre 1.4 shljwr examples of stiR and Rexihle piping When a piping is subjected lo change in Iemprature and if the pipe is not restrained from expansion, no stresses are developed and the pipe just expands or contracts. When the pipe is restrained, stresses and forces of cotlsiderahle magnitude are: created. For example, at a refinery near Houston, Texas, when two axial restraiitts were present in a straight steam line (see Fig. I . I)), the hending of a largt: support frame and the faiture of a pipe at the shcs-pipe weld area

w@u~c$~. The thermal force that is developd when tr3lh ends of a hot piping are reslraivcd is enormous and is also independent ol the length of piping.

'ThermB Fc~rce= E(strain due to expansion)(nletal area)

( 1.2)

Exay d c vJ

Calculate the force developed in a 10 in. sch 40 carbon steel pipe A53 Grade B subjected to ZWaF from an installation temperature of 7fPF. The metal area of a 10 in. sch 40 pipe is 11.9 sq i n (Appendix Table Ad). 'I'llc expailsion coeficienl at 200°F is 0.99 in./l0O (I (Appendix Table A I ) .

E = 29.9x

Iflnpsi (Appendix Table A2)

The layout a l s piping system provides inherent Rexibility through changes in direction. The stiff piping system shown in Rgure 1.4 can be made Rexiblc in different ways. Figure i .5 shows the inclusion of an expansion loop if space permits. An expansion join1 (Fig. i .h) may he added (see Eq. 5.4 for

FICIPLIRE 1.3 Piplnr

with

F

I

O

*

~ bw-~

61GURE 8.7

Leg pravided by turning equipment.

pressure thrust calculation) or the equipment may be turned by 98degrees anti thus provides the leg lo absorb the expansion, as shown in Figure 1.7. When a piping system lacks built-in changes in direction, the engineer should consider adding flexibility by one or more of the following means: b n d s , Imps or offsets, swivel joints, corrugated pipe, expansion joints of the he,ellows or slip joint type, or other devices permitting angular, rotational, or axial movements. Expansion joints and expansion loops w i l l be discussed in derail in Chapter 5.

EXPUNATION OF TERMS REUTED TO PIPE SUPPORTS ANCHOR: A rigid restraint providing substantially full Fsxiry for three translations and rotations a b u t the three reference axes. A large slumber in the order of 10" 2blin. is assumed lor translational stiffness in the digital computer programs to simulate the fixity. The details of a structural anchor n a y he obtained from each company" p i p ssupprt standard. BRACE: A device primarily intended lo resist displacement of the piping due lo rhe action of any forces other than those due to thermal expansion or to gravity. Note that with this definition. a damping device is classified as a kind of brace. CONSTANT-EFFORT SUPPORT: A support capable: of applying ei relatively constant force at Any displacement within its useful operating range (e.g., countenweight or compensating spring device). DAMPING DEVICE: A dashlpot or other frictional device that increases the damping of s system, oRering high resistance against rapid displaccments caused by dynamic loads while permining essentially free movement under very gradually applied displacements (e.gavsnubkr). from a structure, and so I l n ~ c e n : A s u p p r l by which piping is surpnded , I

" I

*

.

?

1

.

L a ~ r i paw: A device that restricts translatory movement Lo a limited ,) arkrtounb in one direction along any single axis. Paralleling the various stops ahere may also be double-aciihg limit stops, two-axis limit stops, 8 ~ $8 d on. Rasa~~sm SUPPORT: A s u p p r t that includes one or more largely elastic m e m k r s (e.g., spring). R a s r r ~ oOR SLIDING SUPPORT: A device providing support from heneath the piping bur orifering no resislance other than friclional to horizontal

motion. R ~ s a w ~ a mAny : device that prevents, resists, or limits the free movement of the piping, RIGID cso~ta_r,SUPPORT: A s u p p r ? providing stillness in at least one , direction, which Is comparable to that of the pipe. STOP: A device that permits rogation bur prevents translatory movement in at least one direction along any desired axis. If translation is prevented in h l h direclions along the same axis, the term double-acting stop is preferably applied. Stop is a!so known as ""Bumper." S U P ~ R TA : device used speciAcaliy to sustain a portion of weigh! of \he piping system plus any suprimposed vertical loadings. '$iwto-nxrs STCPP: A device which prevents translalory movement in one direction along each of two axes.

. ,

lFlGURE 1.8 Guided csntilevec apptoxirnation.

pl;tne system under the guided cantilever approximation, as shown in Figure I .M, The deflection capacily of a canlilever under this assumption can be given Ry Eq. 1.3 (reference 3):

where h = permissible deflection, inches SA = allowable stress range, psi (given by Eq. 4. I D & = length of leg needed lo absorb the expansion, feet g)o = outside diameter of pipe. inches. The limitations of the guided cantilever method are:

Lnce a compiete (weight, thermal plus pressure, and thermal plus pressure weight) analysis of the piping system has been conducted, support msa8ificarions can be: made very easily. Wlsan a p i p line moves as a result of thermal expansion, i t is necessary !ha%flexible hangcrs Re provided that support the piping system throughout its thermal cycle. Three types of hangers are generally employed:

s;pl

I.

Rigid s u p p r t or rod hangers that suppsedly prevent any movement along the axis of the hanger. Rod hangers are used when the free thermal deflections are small enough so ghat their restraint of movement does not produce excessive reactions in the pipinn . . - system. . 2, ,Variable support or spring hangers provide a supporting force equal to hot load (reference 6 ) while allowing deflection. 3. Csnsranr s u p p r l or eonstant effort hangers that provide an essential!~canslant supwrting force throughout the thermal cycle. Ideally, constant s u p p r t hangers do not restrain the free movement of the system and therefore do not increase the piping stresses.

.

I . The system has only two terminal points and it is composed of straight legs of a pipe with uniform size and thickness and square corner intersections. 2. All legs are parallel to the coordinate axes. 3. Thermal expansion is absoskd only by legs in a perpendicu8ar direction. 4. The amount of thermal expansion that a given leg can absorb is inversely proprtional to Its stiflness. Because the legs arc of identical cross section, their stiRness will vary according to alre inverse value ol the cube of their lengths. 5. In accommodating thermal expansion, the legs act as guided cantilevers, that is, they are subjected to &@ding under end displace: meats; however, no end rotation is permitted, as shown in Figure 1.8.

THE GUIDED GAWILEVER METHOD One of the simplified methods used in piping dysign is known as the guided canrilever mcthd, Ixcsuse deflections are assumed in occur in a single-

As a further refinement of this method, a correction I ~ ~ o ~ sllws t l s ~fort reducing the bending moment, due to the rotation of the leg adjacent lo the one c o n ~ i d ~ r eCdR O he 11";er" ( r ~ f e r ~ .lb nr~

I . Talk turns (reference 5 ) 2. BTT Grinnell (reference 6) 3. M.W. Kellogg (reference 3) HGORE 1.9

Anchor with initial movement

Calculate leg & required lor the two anchor problem and force P given in FIguse 1.9. Pipe outside diameter = 45 in.; thickness = 0.237 in Expansion coefficient = 4 in.1100 la Stress range = S, = 15,0(10 psi Cnid modulus = 27.9 x 10"si Deflection B = I + 20(4/100) =. 2,3 in. Rearranging Eq. 1.3 (guided cantilever method):

4

moment PL Bending stress = Sb= -= -

Z

22

4.5 + 4.5 - 2(0.237) = 2.13 in. 2 Z = section modulus = m2(lhickness)= n ( 2 . 13)2(0.237)= 3.38 in.'

4 . Digital computer solution including bend Rexibiliry factors (reference 7 ) 5. Digital computer solution using square corner approach (not including the k n d flexibility)

'Table 9.2 includes the range of diameters (&24 in.), wall thickness, and nomenl of inertia I used in the calcplations. Table l .J shows the configuration of a U loop (expansion loop) an E s h a v , and a Z shape. The maximum bending stress is also given for each method. Figure I . I 0 shows the variation of k n d i n g stress with area moment of inertia I for the loop. Were I was selected instead of diameter because I also includes the e6lecl of wall rhickrress. As can Ine seen the Grinnell method gives very highly conservallve results. Expansion loops are further discussed in Chapter 5. 1.1 1 shows the variation of k n d i n a stress lor the L shape. The -Fivure c7 Kellogg method gives higher stress vaIues. Figure 1.12 demonstrates the variation of bending stress with moment of inertia for the Z s h a p . The digital computer solution using EZFLEX computer progma" gives lower n u n k r s , which is understandable because the other methods are meant to he conservative. The Kellog method is discussed in derail in Chapter 5 (Eqs. 5.2 and 5.31

-

Mean radius r = -

as,z 2(1 5,000)(3.38) Force P = -= L

20.(13(12)

-

42 1 .R Ib

Results obtained from other simplified methods and the digital computer aided piping analysis are compared here. However, each method is not fully explained because the references give a detailed explanation and they also need charts and graphs for their soiurion. To understand the diliferences ljetween each of the methods, results for three problems (Table 1.3)for range a f diameters 6 2 4 in. are presented here (reference 4).

TABLE 1.2

B"IwShes Used 1m Compr~trhorrol Sirniptilied Methods

PIP 0D (rn 1

Sch

6.625 8.625

40 40

Moment of

MduOus of

Wall Thickness

inertia I

Section Z,

(in.4)

(in.')

6.025 7.98 1 10.250 I2.W) 13.376 15.250 17.376

0.280 0.332 0.250 0.375 0.3 16 8.375 0.3 12

28.14 72.50 L 13.70 279.30 314.30 562.10 678.d.M

0.375 n 175

11 14.W ton? n

lnside Diameter

10.75 12.75

20 Std.

14.00 16.30 L 8.W

20 Std. 20

20 00

Srd.

i9.250

91 (W)

"i(l

3'19$;

8.58 86.81

21.16 43.130

44.901 70.30 75.51 111.4 1 6 1 $4

Legend Comp sqriare corner a Camp using e l h w @

0

Tube turns

d Kellug~

x Grinneli

7 Area moment of inertia I in

"

FJGURE 1.10 Bending stress in symmetrical Imp

10' psi

64

turns 4f

b/

Anchor

/I

7

200 400 600 800 1000 I200 1400 1600 1800 2000 2200 Area moment of tncrt~a.In

FnGURE #.I2 Bending stre= in Z-shepd piping.

EXERCISES

Area momenl of rnerl~a,1 In 4

RGURE 1.II. Bending slres in L - s h e p d piping

(a) Find lola! expansion for intermediate alloy steel (5Cr Mo through 9 Cr Mo) pipe at temperatures of ( I ) -55OF, (2) 43 i0F, (3) 1572°F. lf the temperature given is out of range for the material, suggest suitable material lor that temperature. Consider length of 120 TI. (h) Find lor auslenitic steel the following at installalion temperature:

Young's modulus (2) Poisson's ratio (3) Density. ( c ) Calculate total elongation in 132 1t of p i p made of c a r k n steel subjected to 645°F. (I)

(a)

(Ip)

Find E values for low chrome steel at -1 15*F, 7WF, and 800°F. Explain the eflect of temwraturc an E value, Find cold and hot stresses for ASTM A53 Grade B p i v at 7WF and 625°F.

Calculate the thermal force developed in the piping that is fixed at b t h ends as shown in Figure 1.13. It consists of an 8 in. sch 40, c e r b n steel pipe with operating temperature 300°F. Use Eq. 1.2. a = coeficient of thermal expansion st 3280F = 1.R2 in./100 I t

s

epe

-*.**a

Anatva#a

0

Referensaw

FlGURE 1.13 Thermal force

B"

FlGURE 1.17 Calculation of force and rnornent at amhor.

IilGURE 1.14 Unequal legs piping w ~ t hL-shape

4. Ca&cmlatethe stress of the rayout in Figure 1.14. 11 consists of a 10 in. s c t 40,c a r h n sreei p i p of A53 Grade B mareria! at 5f100F. S, = %O,OC)(lpsi

5.

*

Sh = 17,250 psi

A I0 in. sch 40 c a r h n steel pipe with A53 Grade R material has a temperature of 200°F. The allowable stress S, .= Sk= 20,000psi. Cala cerlale leg L needed in Figure i .15.

a 5 in RGURE l.lB Piptng connected In a vessc

6. Two equipment nozzles have thermal movement and layout as shown in Figure l.!6. What will be the length L? The carbon sreei p i p has a nominal diameter o f N in. and a = 9.82 in./l(N) TI. SA = l18,000 psi

For a 6 in. sch 4 0 c a r h n steel pipe A53 Grade B, the linear expansion i s 3 in. Allowable stress range SA = 28,CBOO psi. 8,

E = 27.9 x I On psi

7, Two vessels are connected by piping as shown in Figure 1.17. What is the length required for lhe leg? What is the force and moment?

A vessel has an average operating temperature: of 500°F"'. With a line from the vessel nozzle going to an equipment as shown in Figure 8,18, what should be the length L? Ir is a \ 2 in. sch 4 0 pipe with a temperature of 400°F. The pipe is of A53 Grade B material. S, = 20,00(1 psi and &, = 16,350 psi. (Ira practical cases, L is limited by tower height.)

0 5 in

REFERENCES

i I

0 6 in

I Z

ANSIIASME 83 1 3- 19RO Ckcmical P k n t and k"c@oleurn Refinery Rplng ASTM Annuel Book ol ASTM S~anderds,D~flerenr /or Di&rcnr Mfmab.

ACURE 1.15 A Z-shaped piping with initial anchor movements

3 4

M. W Kellagg, Design oj Piping System. New York:

Estrems, Fernando and S. Kennappan, "Comparimn ol re~ulrsfrom diflerenl simplified methods with digital computer calculations " 9. T u k Turns Division of Ckmctron C o v . ""Piping Enginecsin~,Line Expamion a d Rexibility." 6 1TT Gdnncll industrial Piping. "Riping Design s d Engineering.'" 7. EZFLEX Piping Flexibility Analpis Program. 8. Crane Company. ""Fiow of Fluids.'"

L i CHAPTER

where d =. inside diameter = D, - 2r Eq =quality factor that is the product of casting quality factor &, joint quality factor 4, and srructural grade quality factor E, when applies. Values of i$ range from 0.85 to 1.0 and devnds upon the method used lo examine the casting quality (see Table 2.2a). Value of EI ranges from 0.6 to 1.0 (given in Table 2.2b) and depends upon type of weld joint. Values of & may be assumed as 0.92.

TWO

DESIGN OF PRESSURE COMPONENTS

GALCUMTIOM C)F MINIMUM WALL THICKNESS 09":A PIPE

TABLE 2.1

Vetoes eol V CoeRRclcnt I s k Uwd In Gq. 2-1"

a

Piping codes require that the minimum thickness fm, inclttding the allowance for mechanicai strength, shall not be less Ihan the thickness calculated using Eq. 2.1. I

1

*

I

Ferritic steels Austenitic steel Cast iron Nonferrous metals

04

11 5

(1 7

04

04

0.7 04

0.7

04 04

-

-

-

-

04

-

-

09

"Reference ANSIIASME 8.71 3, Tablc 304 1 I

where

-

lm minimum

-

=%d

J

required wall thickness, inches

r = pressure design thickness, inches 6" =: internal pressure, psig DD= outside diameter of pipe, Inches S aOBowabIe stress at design temwrature (known as hog stress), psi (see Appndix Table A3) A = allowance, additional thickness lo provide Tor material removed in threading, corrosion, or erosion allowance; manufacturing tolerance (MT) should also be considered. Y = cwRcient that takes material properties and design temperature into account. b r I < d / 6 , values of V are given in Table 2.1. For temperature below 900°F. 0.4 may be assumed.

&-

Type of Supplementary Examination

Sudace examination (1) Magnetic particle method (2) Ultrasonic examination (3) Type I and 2 Type I and 3

0.85 0.85 0.95

T y ~ e2 and 3

1.W

*Reference ANSIIASMF R11 1 Tahle 302

0.90 B .CICB

3 7r

0.7 0.7

-

m

w

1PS

eslculallon s(

h

(1 Minkurn Wen Thlcknrro oil P@co

28

I

From the manufacturer and p i p section p m p r l i e s information, (see Appendix A4) a l o i n . p i p with sck 20 is selected with nominal wall rhickness 0.25 in. T;or p i p s under external pressure see Eqs. 9.10 EIecrrie resistance weld Electric fusion weid (single butt weld]

As required hy specification As required by specificaiiorp

tl R S O Kt1

Electric fusion weld (single butt weld) Electric fusion weid (single butt weid) Electric fusion weld (double butt weld) Electric fusion welcf (double butt weld]

S p ? t radiograph

(1 YO

If%Ooh radlogrnph As

required hy ~pectlicatton

Spot ratl~ogr;~ph

E2ectric fusion weld (tloerble butt weld) BY ASTM A2 I 1 specification Double submerged arc.. welded p i p (wr APB 5L or ~ L X )

ItN)O/n

r;$cPtogr;iph

AS required hy sprlfication

Radiograph

-

I

~ , ~ ~ o k at i n ~g q 2.1 . again, we see that: r,=ocA

(w)

--

0 85 0 00

I

TCIIcknesr

Ail@mal@E q u a t i ~ n to s Galculatcr

PI;q,

+A

;?~sE,+ PY)

12.11

where r is the pressure deqign thickness in inches. Equafionq 2.3 and 2.4 (I-am6 equation) may aiso Re used lo calculate

cn)

l=-2-

0 75 0 '15

Pr),

il:

(2.3)

2 SEq

(2.41

"Reference 831.3 ANS:/ASME 302 3 4 I pJ

Exa mpba

.

the' minimum permissible wall lhickrlcrs frlr a in n6~nlit12,~ diameter pipe under 351) psi and hSII°F. Material is ASTM p, 106 Grade R cormsion all0wance is 0 0 5 in., and mgl{ tolerance ( ~ , ris ) 124%.

--

Thickness r, = 350~sig

=

=

De = 10.75 in.

PDe + A 2(SEq + PV)

8,

=

Nominal thickness =.

1

The allowable working pressure of a pipe can be determined by Eq. 2.5:

stress (tensile) for A I Oh Grade B = 17,000 psi (see A p p n d i x A3)

3SO( 10.75) - + (1.05 = 0.144 in. 24 17,0(M1x I + 350 x 0.4) 0.144 0.144 - = 0. I64K in. ( 1 -MT)-61 -0.125)

Allowrrbte Working Prrrsauro

(2.1)

E, = 1.O for seamless pipe

-65.4 ( h c a u s e the lemperature is less than 9fNrF)

Equaticlns 2. l, 2.3, and 2.4 are valid lor r < C),16 (thin p i p ) . The pipe with 1 2 D/h (thick-waliled pipe) or PISE* r 0.385 requires consideration taking design and material facrors inlo accOunl suck theory of failure, fatigue, and thermal stress (reference 1).

a(SE9)8 P = Da-2Yf

(2.5)

where r = specified wall thickness or actual wall thickness in inches. the minimum wall thickness after k n d i n g should not be less For than the minimum required for straight pipe. Blanks

'9r0

I - c@rn~"*~~,@a

8

I

wh

.,)

4 zinsae

dhme!er of gasket o raised face or 11. iplrilllface flanges Or gasket diamefer forbringjoint and fuliy refaioedgaske,ed flanges in inches.

lest Fr@ssur@ hydroitalic g s f ~ressurea[ any p a i s in the system sl.,uld

'8 minimum

iesy design prtssure. For kmperagures above o s ( l o ~,he , pressure P, i s given by:

(Design pressure) 6

=

Stress

(

42.7) (see n p p n d j r Table

5

&sign temperature (& at design fempemgurel

Allowable Pressure in Miter Ben&

M a ~ l)cm&* r An angular

of 3 degrees or less (angle o in Figure 2.2) dries "quire as a miter bend. Acrepfahle methflds (,,, /'ressurc design of mutliple and single miter bends are given in (a) i,sd (h) -iPext.

Mec''i~'e Itlifer The maximum allnwble internalpressur, shr,, lesser value calculated from E ~ s2.Ra . and b T b w equafil,ns arc not applicable when 8 exceeds 22.5 degrees

T-c .643 tan B

Pm =

aD,,==

J

(2.Ha) ~ (2.Hb)

( b ) Si@gk m r Bends (or Widely Spaced Miler Bends) ( I ) The sllnwabfe imemal p.crsure for a single milcr bend @ not greater than 22.5 depries shali .alrubkd by g q The maximum aliovabte internal prwure for a sing,c mi[sr &d , with @ greafer than 22.5 darers shall calculafd by E~ 2 ~ ~ T-c

Pm =

( T - 1 ) + 1.25 [an B*Ftom ASMUANSI BJt 3. Letinn 18( 2 3

(2.8~)

:

I i

dam*

-i b.4

.8(r

t') \
lclo wiihstirnd rl~isirdtliticlnal load dtte 10 t o r ; h t cold spring i t t ccllc! condition. 'l'hc tlcflcctio~isi ~ irt cold springjocirtion still remain the same, hecause tllc colt1 sprit~gonly rciocirtcs tire pipe wc9d point and does not reduce titc ibcitbirl ex[t:t~isiolr.This actrribl rleflcctinn is important in the spring rlc.;ig~l. I F i~llcntionis ntrt pitic!, the splippp: m;ny he 1lntlersi7.ed for tlcllcctic?rl. ('clltl spliitlr, rlcctls to I>c specifctl it1 weld poirrts lo save cost of ; ~ t l t l i i i c j r ~ ; rwc.lrling. l Meximum Reactions far Simple Systems'

Itr) P I i f I . 1 : l ' h e tcmpcrattorc for this c.~~niprll;tliot~ is t l ~ cnr;rui~llrrnlt?r nlinintrtm n~clolbcmpcritlurc, whichcvcr ~wotl~~c,c.s 6I1c I;lr gcr K C ~ I C ~ ~ O I I :

coltl-sprirlg F;~ctorvaryittg I r o ~ n zero lrrs no cold spring to I .Ofor I(1O0h, cold spring. ('!'he f;tclor 2/3 is hitscrl o n cxpcricncc. Illat slrows that spcrilicd colt! spring cannot he fully assrrrccl, cvcn wit11 clahori~lc prceaulions.) Usually C' of (1.5 is rccornmentlcd. E,, = nlotlrtlus of elasticity at installation tcmperattrre I:',, = modttlus of cli~sticilyaf maximum or rninimunr metal lernpcratrirc K range of rei~clionlorccs or nromcnts (dcrivcd from Rcxibiliry analysis) corresponding to thc fall! displacement ?;tress range add hesed o n Ea K,, = cslimalecl instantanetrus maximum reaction lorcc o r moment art maxilntlnl or minimum metal tcmpcralurc ('=

Anchor

-

Norrle &!(;(IRE 4.6 i'ip~np in itti!i;tl (carlt!) ant! final fhclcl p b \ t ! t o f ~ 1111dvrCIIIC! \riririg

Y P o r i g i ~ a C'nndition r R,: T h e temperitltlre for this c o m p ~ ~ t i ~ lisi ott,, n 10) e x p k f e d lemperaturc at which the piping is to hc assembled.

R, = C R or C",R , w!~ichcver is grcatcr

I'ipitlg nlalerial is slainlcs%slecl A 3 i 2 TP 304. T h e lempcrarure is 9OI)"F. I ' t r r;rlcul;tte ltor reaction, usc Eq. 4.12:

(4.t 3 a )

where norncnclattarc is as &fore and: where K = nrornent helore cc~fdsprnng = 2500 It-lb t ' = 0.55 Em = hot modulus = 23.4 x !Oh psii. at 900°F for stainless sfeel ( A l ~ e n d i xTable A2) I,, = cold modult~\= 28.3 x 10" ~ $ 1

Cl = eslinrrted sell-spring or relaxation factor; use zero if v;~ltico l C', is ncgativc. R, = eslirnatcd instantaneous reaction force or nlr>mcni at insla1l;ttictn (en)pcralnrc SE = cornpuled disftlaccnient stress range (from Eq. 4.6) :dk hot S ~ ~ Q I Spsi S,

-

= 2SoO(tt.37)(0.82ttV) = 758 It-lh.

'l r ) ci~lcul;tlec.trf(l reacrion usc Eq. 4.13;1:

For nlultianchnr systems and for. two-anchclr systems with internlcdiir~c restraints. Eqs. 4.12.4.1.7a and h are no[ applicable. Each case mils! he st~ttlictl to cslimalc location, nature, and extcrrl of !oral overstrain anil i t s ctfcc.t o n s'ress dfstribu~ionand reactions. .' If a piping systcrn is designed with different pcrccntagcs of cc~ldspricig in mrious directions, these equations are not icpplicahlc. In [his c;isc. the piping system shall bc: aniriyzcd h y a comprehensive mcthocl. The ~ i ~ l ~ t ~ lhot i~tcd reacrionsshall hc based on theoretical cold springs in all dirccticlns not grcilicr than two thirds of the cctld springs as specified or mcnsured.

10, Calculate colti and hot reaction moncnls at nolzlc (Fig. 4.7) ;rltcr 55'%, cold spring if moment wirhr~u!colrl spring was 2500 fl-lh from piping

. analysis.

wltcrc

"

or

C'# I(, whichever is prcatcr

(', = rcliixaiion Factor

Bccausc t l l c r ~was riot enotlgh inlormittion t o calcula~ccornptrtcd cxpi~n\io~l stress range S, , factor C , could no! bc caBI~.IIIated. C'cbitl rcircliorl. R, = ('W = 0.55(2500) = 1.775 18-lh la is in~portancthat the equipnrcnt nt,i.;.lc should withstand not or~ly 7 5 8 fl-Ib in an operating condil;ion, hrrr alsc~ 137.5 11-lb in a cold condition.

EXERCISES

Cul short

lbow

RGklllE 4.7

N, = C'R

Momen8 cslcularion under cold spring

I:ind cold stress and hot stress for a carbon steel scamless pipe at -36PF, h75"F, 1 125°F: ( a ) material is A93 Grade A; (6)material is API 5 L Grade B.

A mraring, equipment norzle can only allow a force of XOOlb during operalion (Fig. 4.10. 7'hc carlwjn steel pipe will have an clpcrating " lcn~pesattirc"i0bol: arli! :ic;~lcrrl:~cc-ci I n r c r * r r f ~~*~~ 1%

lslerc

--_

i

\ J'

8%

0. (';llculatc the rhcrmal expansion stress for the branch and the header according lo ANSl BJ 1.3 code Itor the loacting (given in Example: 9 and in rzig. 4.5) at the branch intcrsecrion: rhc branch and the header are 12 in. standard wall and 8 in. sch 40 well. IT

FIGURE 4.8 ('old spring cxanrple.

REFERENCES I

4,

At what condirion can cold spril~ghe t~sctl'" .is# t l i l l i c t ~ i ~~iIiI~C~O I I I I I C F ~ ~ I

with co!d sprir~gin theory

;silt$ pr;lciicC.

d h ) B';bler~lirlc.Itrngiltttlittill stress iri it 1-7 I! sEitttclit~t!\$t*ig!~!~ c i t l i t ~cll>o~v g wherr: Inp9;rrrlc I?eslr!ing nlonlcilt = 47.3 1.1-11) CDtttplitnc bentling Inrrnlcrll = 32.5 .T11-1I> Axial force = 0 2 8 ill M;~tct-iitlis Ft5.1 iirarlc A ilnd ~cnttlcritlr~c-c i\ OS2"1'. v8

6 , C"alctr8;ale SII; a i ~ dflexibility f i ~ c i t ~ r : ( a ) h in. lttng rarlirrs sfit,ttl;trtl 111ickrt~ss ( R l b"1l9cul;rrc cctrrc:ctctl ?.ill: ;~ntlti if tl\c cll~crwis twtr C K ) ~ ll;tr~gctl. \ fcb M i ~ c rb c i ~ dwiih = i 5 O i111tI ! 2 in. ( l i : ~ n t ~ ~ w ci lr! ~t l ~ i c k t ~ 0.25 e~~ ill,

7*

( i t ! c ' ~ t ! ~ t l i l iilCr!nitI l#~ ~ x p i i t ? ~ i (f \ tt lb f ~ ~ the

p i p i ~ ~S !gI ~ ) ~ V Iilb I !'igittc 4.0. pip^ is i f ) i l l . S C ~ I8 0 ,453 l i r ; ~ ~1%!pil~c ~ i ~ ttOtB"!:. t (RI 11 t l ~ ctIislil8tcc ~ C I W C C I;I ~ r ~ c h $is~i~tcrci~sctl rs to 300 I t , W I I ~ I I will IIC 10c

.!'he

force'!

8

-

!"or it s~ilmlcsspipe, A 5 3 Ciririlc 13, the i~llowithlcxlrcsscs ;I[ 74Y'i.' ;trirl h0OnO.' itre Zl),OllO psi i+ntl 17..30(lpsi, rcspcctivcly ;iccorclitlg lo ANSl 8 8 1 1.3 e'rrilc. B'trr it12 acttrill pipir~g\yslcrrl ;rt (iOfFl:. (Btc ctr~l~l~ttlctl pilli~rg strcwcs at ceslirin Ig~cirlionsarc: as follows: (a1 I.ol~giOrdin;llstrcss tlt~ettl; pt-csstrrcwcigl" l ; r r ~ t botllcr s~rslitictctlIcii~tling is VXBIO psi. (RE C'ompktlcd displ;tccmcnt slrcss ribngc is 3 3 . 4 7 psi. ( c ) Slrcsscs clue Itr wind I t r i ~ t lis 5K22 psi. Iloc.; h i s piping systcnl mect the slrcss cri!cri;b lor ANSI 113 i . 3 cc~lc'?

FIGURE 4.9

Axial ftjrre in restrained piping

ANSI 853 l . I - 18b,N(B. Power Piping C'tdc.

ANSI 113 1 3- l O U 0 . C'l~emicalPlant and Pe~rokumRclinery Piping C'twlc. I , ANSI l)l 1.4- I V7.4. Liqrtid 'l'ranrp>rlalitrnPiping Ctdc. 4. ANSI H? I .X. I)()1'. (ias 'l'ransmissitrn 'l'ranspctrtation Piping. C'c~le. 5 . ASMI:. Scctron 141. Nuclear Comptrncnl.; ('tnlc. kfi~rkl.Arc "I'rliguc 'I'esls trl Piping ( ' c ~ ~ ~ n c n l7ians. s , " ASME, Val. ?4(3), pp. 217-3113 ir !April 1V)52!. 7 KtKT;ih~,,ph. I:. ('. "l3ltect of lntcrnal Pressure o n I..lexibility and SlF on C'urwcd Pip,'" lolrnrul crf Appltc.d Mt.c.hanirt.Val!. 24; 'l'rans ASME, Vt.rl. 70 ( M a y 1957). K . R(;rchacck,S."llcsign and Operation trl a 1-argc Diameter Steam Linc at Onlario Hydro's Ortrcc N~~rlcar Powcr I~evclopmen#," ASME. 78-PVP-86.

CHAPTER FIVE FIGURE 5.1

Symnelrical Imp

EXPANSION LOOPS AND EXPANSION JOINTS

:

A s c1;scsibcal earlier i n Chapter t Jwo ticviccs uscd t o i c t ~ p r c i vthe ~ llcxihilityrrf pipiujg are cxpitnsion loops and expansion joints. '!.his ehijptcr will rlcirl with the?;#: t w o topies in more derail.

EXPANSfON LOOPS L-qjps provide lhc ncccssary k g t j f piping in a perpcrltlic~I;~r l : ~EXPANSION ) JOIN^: A n internally guided expansion joint is d e s b n c d in provide axial guiding within the expansion joint by incorporating a heavy telescoping internal guide sleeve, w i t h or without the use of heitring rings. (Flore: T h e use o l a n internally guided expansion joint doer not eliminate the necessity 01 using adequate external pipe guidut;.) U ~ t v r : ~ c nEXI~ANSION l Jclf~r.: A universai expansion joint contains two beltr~wsb y a c o m m o n connector f o r the p u r p s e o f absorbing any cornhit~;ttion of the three hasic movements, that is, axial movement, Iirtcrir! deflection, and angular rotation, Universal expansion joints are ttsuiilly furnished w i t h l i m i t rods to distribute the m o v e m e l t between the IWO ~CII~IWS of the expansion joint and stabilize the c o m m o n connector. 'I-his definition docs not imply that only a double bellows expansion joint can absnrh universal movement.

SIIJ(;II

I#,

Squlrn~in a B e l b w s Explnricrn Joini: A tern, e m p l l ~ y c di t , clcal,lr i h c t9ccurreflce of inslability due In internal pressuru ;III~ is predt,nlinittcly assa~ciatcdwith joints OF 2 0 in. dianleter or sm;rllcr. F

~

~fl a~n t pha t l si i o n~lvinf: ~ ~This can he igtcreasud try ilgjnarr ~lclll,ws

(ma\:t still he wilhsl;~nd the pressire). i~xcrci~se i n tjumt~erg j f hellljws, ane%y multiple k l l o w s . Erlerllnl Cover: A cover used t o protect the exterior c ~ fthc hcllt,ws fntm foreign objects, especially when the joim is buried undergnnind, Infcm;bi liner o r slecve is used for the h)lltrwinp:

2

where f l o ~ ~elfbciliesare high (for stc;lnj lines whe~,v e l ~ l c i t yC I ~ L . C ~ S - fiMMffiminlill. o f diameter i n lines upto 6 - i n sixe) 3. when abrasive materials are presenr 4. !hen rhere is reverse o r turhulcrt! flow 5, for all hifi temperacure applications 6. for 318 copper elbows W h e n lateral dellecth>no r rotalion ir present. the liner must he sulficicnlly smaller in diameter 80 provide the necessary clearance.

Tie Rods: These are mdr o r bar devices l o r the purpose o f restraining the expansion joint f r o m the thrust due to internal pressure. T h e numher and sire o f the rods depend u p o n the magnitude o f thrust force. Tie rods may also act as deflection limit rods.

EXI'ANSION JOIN.I : A hinged expansion joint containsone k l l o w s and is designed 1 0 permit angular rotation i n one plane o n l y b y the use of a pair 111 pins i h m u g h hinge plates attached t o the expansion joint ends. T h e hinges and hinge pins must h e designed t o restrain the thrust o f the expansion join8 due t o internal pressure and extraneous forcer. where applicable. H i n g e d expansion joints should k used in sets ol two or three t o luncric~nproperly. SWIN('I EXPANSION Jcfl~r: Pb swing expansion joint is designed t o a h o r b !atera!

!il~(il.f)

deflection and/or angular rotation in one plane. Pressure t h r u d and extranectus forces are restrained b y the use o f a pair o f swing bars. each of wlticti i s pinnetl to the expatlsictn joint ends.

.

-,clees 1

(1%

E x a h ~ s l oJOIW: ~ A gimbal expansion joint is designed Lo permit angular rotation in any plane by the use of two pairs of hinges affxed to a common floating gimbal ring. ~ h gimbail d ring, hinges, and pins must be designed Is restrain the thrust of the expansion joint due to internal pressure and extraneous forces, where applicable. PRHSUREBALANCED EXPANSION JOIKI: A pressure balanced expansion joint is designed to absorb axial movement and/or lateral deflection while restraining the pressure thrust by means of lie devices interconnecting the Bow hilows with an opposed kllows also subjected lo line pressure. This I y p of expansion joint is normally used where a change of direction wcrrrs in a run of piping. The Row end of a pressure balanced expansion joint sometimes contains two bellows separated by a common connector, in which care i t is called a universal pressure balanced expansion join^. GlMb. ,L

.I

4 ,

'

7

anchor force should include pressure thrust, centrifugal thrust, friction at supprts and guides, and force to compress the bllovvs.

using the EJMA [relerence I ) equarion, calculate hydrostatic examination t e a pressure if the design pressure is 125 psig and design temperature is 5WF. The bellows material is c a r b n steel ASTM A53 Grade ?'he test pressure is: (using Eq. 2.7)

EZ.

where Pd = design pRssure = 125 psig * $ = allowable stress of bellows material at test pressure (70"R = 20,000 psi ( S , from Appndix A3) Sd = allowable stress of bellows material at design :ernprmlure of Sl)(FF = 18,"J)fIpsi (Sk from Appendix A3)

PRESSURE THRUST FORCE Tile static thrust Fsdue to internal pressure is given by Eq. 5.4:

8,

i

'

where a = eflective area corresponding lo #he mean diameter of the corrugations, sq in. p =design line pressure based on most severe condition, psi ~ ' h force e required lo campress the expansion joint in the axial direction F.. is:

Fm = (axial spring consranr)(amounr of compression)

(5.5)

The centrifugal thrust l$ at the elbow due to flow is given by: 2ApV2 @ Ffl = -sin 8 wilere A = internal area of pipe, sq in. p = density of fluid, Ib/lt3 V = velocity of Flow, ftlsec g = acceleration due to gravity = 32.2 Fr/sec2 8 =. angfe of k n d Figure 5.17 shows the elbow where a main anchor is located. The design

i

R G U R E 5.17 Anchor lorce

anchor st

eibnw.

I, (a) Size the expansion loop for the lollowing conditions: Diameter = 16 in. standard weight Material = A53 Grade A = 220 I t Distance between anchors 80Ib Vlltllt of pipe length Span = 25 ft Temperature = 750°F (b) Calculate the force at anchcars lor shoes with Tenon slide plate. ( e ) Calculate the force st guides.

-

(a) Design ths expansion imp, by equation, with i m p height lo width ratio as I . Distance between anchors = 225 ft Ternpralure = 800°F Span = 20 Et Diameter -. 12 in. standard weight Material =; A53 Grade B (h) Calculate the force st anchors for shcres with steel on steel. (c) Calculate the force at guides.

3. (a) CalmDale the thermal expansion at A and B in the piping system given in Fieure 5 18. Material 4106 CIr~deR p t 75F".

L f

.

t

hi

r

- Ex,

I,

Joe, \

10 f t

js

mGURE J.ZZ

FIGURE 5.18

bop.

7. Size an expansion loop based on the following conditions: a 12 in, A53 Grade B sch 40 pipe; temperature is 350°F. Imp width is 8 It; and length of p i p is 1 80 ft 8.

Number of loops

FIGURE 3.19 N u m k r a l Imps

(b) Which of the following is advantageous to use: ( I ) symmrlrical expansion Imp? (2) unsymmetrical expansion loop?

4. The dimension of an expansion loop is limited as shown in Figt~re5. I 9 If a pipe has a temperature of 6S0°F, how many expansion lnops are required lor 500 11 long pipe? 5.

11a line is anchored at both ends, but anchors have thermal movement as shown in Figure 5.20, what is the sire of the loop? It is 4 in. sch 80. A53 Grade L) carbon steel pipe at 350°F.

6. A 6 in. diameter loop has standard sch A53 Grade B pipe with operating temprelure 375°F. For loop sbown in Figure 5.2 I: (a) find resultant b r c e F at anchors; (b) find moment M at anchors.

lilGURE 5.20 Loop size.

FIGURE J.ZI

Laop

Expansion joint.

From manufacturer's catalog find overall length of Reriblt hose needed for klrf in. oflset deRection for a 6 in. internal diameter hose. Assume type of end connection.

9. A 12 in. diameter carbon steel standard weight p i p is at 525°F. Design pressure is 180 psig. Wit11 a single bellows expansion joint in Lke piping system in Figure 5.22, calculate forces at nozzle and anchor. The mean area of convolution is 151 sq in.; the axial spring rate is 882 Ih/in. LO. A 4 0 in. diameter turbine exhaust duct system is fabricated of in. well c a r h n steel and operates at Full vacuum at 320°F. The movement at the turbine exhaust flange and the condenser inlet are determined as shown in Figure 5.23. A universal pressure-balanced expansion joint is located between two piecesol equipment with the dimensions as shown in Figure 5.23. Determine the forces and moments due to the bellows sliFTness at the condenser and turbine connections. The data provided by the expansion joint manufacturer are as follows: Mean diameter ol bellows d, = 42 in. Working spring rate f,, = 32,000 Iblin.lconvolulinn Number of convolutions Row bellows Nf = 6 + 5 Number of convolutions balancing &!lows Nb = 6

ExpansIan Loops and Expansion Jalnbr

--

CHAPTER S I X

FLANGED JOINTS CiliGURE 5.24 Single bellows expansion join!.

11, A single &!low expansion joint is placed in a 2 0 in. diameier c a r h n steel pipe: tlral runs between anchors A, El, C. Anchor point B is actually a directional guide that restricts only the axial movement. The lirle is operating at 150 psig and 550°F. Pipe lengths are shown in Figure 5.24. What are the forces and moments acting a# A, B, C? The data provided by the expansion joint manufacturer are: Eflccrive area corresponding lo kllows mean diameter = 480 in.' Mean diameter d, = 2 1.5 in. Working spring rate 1, = 24,8tN) Ib/in./convolution Beliows tree rengrh = 12 in. , Number of convolutions N = 12 ti

B

REFERENCES 1. Expansion Joint Manufacturers Association 1973 Addenda lo Sgandards of EJMA. 3rd ed., 1969.

2. R a k t t IL. Benson, Chemetron Corp. "A Basic to Analyzing Piping nexibili~y,"(Xcmiral Engineering (&l. 23, 1973). 3. Engineeringdare on expansion joints are available from (company or lrade name): Pathway, ~ e x a o i c sAdxo, , Solar, Anaconda,Temp. Fex. Tube lurns, &Ilea Brtls.. and Metal Bellows.

f:langes are used to join sections of pipe Pcngrhs and to connect piping to eciuipmcnts. Two main types of flanges are flat face and raised face. in pipe \tress analysis, the capability of a flange to carry external moment is given impclrtance. The actual design of flanged joints can be obtained from other sources (references 1 and 2). The eflecls of bolt preload, pressure, temperature, and external moments are cliscussed below. I30lr Preload: The initial tightening of the Rolr is a prestressing operation. -The amount of initial h i t stress developed should bc enough to provide against a!\ conditions that rend to produce a leaking joint and at the same time not so cxcessive that the yielding of the b l l s or nanges can produce relaxation that can also result in leakage. For the joint to be light under hydrostatic (one and hall times the design pressure) pressure, an initial Roil stress higher than the design stress value may be allowed. K 7 S I Internal Pressure: When internal pressure is applied, further yielding of b rnay cause reakage if the margin between initial bolt stress and yield strength Is less. External Pressure: The combined force of external bending moment and I-loll loading rnay plastically deform certain gaskeb that result in loss of gasket pressure when the connection is depressurized. I'ernprature: lncrease in temperature reduces the pressure to which the flange can be subjected. At elevated temperatures, the design stress values are governed by creep rate. If the coeRclent of thermal expansion Is digerent (diflerent material) for Wange and b i t s , leakage rnay occur due to increme in boll load. Then retightening of the bolt may be necessary, but it must not bc forgotten that the eflects of rewsred retightening can be curnuiarlve and may

,,,ccssitate the removal of the cornpnent from service For inspection or repair (,I damage to the component or support.

f

S, yield stress of flange malerial, psi @ $oil circle diameter of flange, inches

Ab total cross-sectional area of bolts at root of thread, sq in. Do outside diameter of flange raised lace PW pressure concrlrrent with bending moment under dynamic loading hi: diameter of location of gasket load reaction, inches (can be approximated by inside diameter of flange raised face) S allowable bolt stress, psi Units: moments It-lb stress psi ODE opraling basis earthquake SSE safety shutdown earthquake SAM sesimic anchor rnovernent Faulted condition is associated with SSE or pipe break. I t i s an extremely low probability event. LOCA b s s of coolant accident. The result would be an irledvertent o p n i n g of the pressurized safety or relief valve because of the loss of coolant in excess of the capacity of the reactor coolant make up system.

GOMPARlSOlBI OF ALLOWABLE ANT) ACTUAL MOMEMS

Method 1: (high strength bolting option) the design limits and sewice level (irnits A and B are:

S,i36,000 should nor be greater than unity.

As can be seen, the results of Eq. 6.2 wili be t w o limes that of Eq. 6.1. The design limits and service level limits C and D (faulted) are:

EXTERNAL MOMEWS The eRecr of external moments wil! be discussed in detail. The allowable moments can k calirdlaieci by :he three methods outlined hy ASME Section 111, NucDear Power Plants Components Code NC-3658. ilgerhod I: This refers lo ANSI 816.5 Ranged joints with high strength bolting (bolt material with allowabie stress at 100°1; not less than 20,000psi).

In method 2: (For flanges at moderate pressures and temperatures)

(a) For service ievels A and B under slatic loads give.n by Eq. 6.1 (b) B"or service levels A and B under slatic and dynamic loads in Eq. 6.2 (c) For service levels C and D under static and dynamic loads in Eq. 6.3 Merhad 2: This method concerns standard flanged joints at moderate pressures and temperafures in ANSI 13 16.5, MSS SP-44, API 605 standards (pmssue less than 100psi and temprature less than 200°F).

In method 3: (equivalent pressure method)

Method 3: This is the equivalent pressure method. Levels A and 113 service limits must be satisfied for all loadings identified in the design specification in the pedormance of its specified service function. The eornpnenl or support must withstand these loadings withour damage requiring repair. b v e l s C and D service limits permit large deformations in areas of . slructura! discantinuitv Ttlc. -It - * .

where A.l is the largest moment (actual) from Ergs, 6.7,6.8, and 6.9.

s

~ r c l r r r n - r -

a*

&)cijuallfy

the flange under this nrelhod,

P,,plus design pressure should be less lhan the rated pressure

.._, I

6101

[~ ./ 750°F. However, compressed sheet askstos-confined gaskets ere limited as to pressure provided the gasket material is suitable foe rht

temperature.

(h.6h)

Actual Mormerrls M(normal)= M..,..,.,.,ic = higher of torsional or resullant of two bending momenls lor gravity plus thermal normal loading, sustained anchor movement plus relief valve thrust force and orher mechanical sustained Ioads. (6.7) Mfupret) =

I

,

99793.

P i ~ ediameter = 30 in. The OD of the flange raised face = 33.75 in. N u m k r of bolls = 28 Total bolt area = 28(0.8898) = 24-94 sq in. Diameter of boll circle C =: 36 im*

= higher ol torsional or resullant of two bending moments plus thermal upset plus OBE plus SAM ONE plus LOCA

(6.8)

Mlfaulled) = M.,,..,d,,,,8c , , u , , ~ ~ , = higher of torsirri~al crr two resultant bending moments plus thermal upsel plus SSE plus SAM SSE plus LOCA (6.9) M = greater of the a h v e three actual moments (6. 10) This moment will be used to pet equivalent pressure.

AS can be expected, lor approving the use of the Range a! certain locations - 2 the actual or calculated bcnding moments must be lower than [he allowable momenb. Table 6.1 gives the equation numbers L>r the aclual and the

calculate the allowable and acrua! k n d i n g moments and check if the given Range is qualified according to ASME Secrioo 111, NC-3658 (summer "

I I

I he flange material is c a r b n steel SAIOS The bolt material is SA1Y3 Grade B 7 Bolt allowable stress = 25,000 psi Flange material yield stress S, = 32,8(M)psi Pressure raring = 150 psi Design " temperalure = 200°C: Design pressure = 175 psi Actual moments (It-lb) From piping analysis is given in Table 6.2, The higher of the torsional moment ar resultant bending moment is

a81owsrble moments for comparison. Garkru: Section NC-3647.5 allows only metallic or asbestos gaskets if the expected normal service pressure exceeds 720psi or the temperature

TABLE 6.2 ~ e a u d~ o m r s l slsam Piplag A ~ Y(fa-!b)s ~

Dead weight Thermal

OBE OBE SAM SSE SSE SAM LBCA

M ,,, ,,,,, M ,,, M w,u.

1,939

6,350 7,979 0

8 1,520 2,825 9,817 0

18,354 0

16,638

61

10,448 0

0

0

0

1 1,682 6,950

12,650

0 lYv646 0

0

(normal) = 1 1,682 + 6950 = 18,632 It-lb (Iron Eq. 6.7)

,,,

td

1,084 i,90 1 8,s I8 0

-

(upset) = 1 1,682 + 6950 + 12,650 = 31,282 [from Eq 6.81 (laulled) = 11,682 + 6950+ 19,646 38,278 (from E q 6.9)

1 1,682 6*950 % 2,650 0

89,646

0

0

Jt..

'.

#'

'4.

,

.bted in Table 6 . 2 Equalionr 6.7, 6.8, and 6.9 are to calrulac total actual moment for normal, upset, and faulted conditions. t

ALLOWABLE MOMENTS The ball material is S A l V Grade 0 7 alloy steel with allowable strcsi 25,OW psi. Method I , known as high strength b l t i n g option. is used because the bolt allowable stress is greater than 20,MH) psi at IVO°F. Thus Eqs. 6.1.6.2, and 6.3 we used to calculate allowable moments.

&farlow dynamic

(faulted) = ( l 1,250)(24,92) - 2 (11~702(1 16

"

1

Table 6.3 gives the comparison of moments of the Example Problem.

.

The effect of Range maleria!. Range rating, and Range diameter on allowable moment shorn in Table 6.4. internal pressure at flange is 175 psi, As can ~ x ~ c l the e dallowable moments are higher lor larger flanges and higher ratings. The allowable momenu for carbun steel Ranges are higher than for stainless steel flanges because yield stress (used in high strength bolting option) for c a r b n sfeel is higher. The yield sfrength (or carbon steel is 3 2 8 W ~ s as i compared with 2I,1W psi for stainless steel at 200°F.

I. ASME !kc. ill. Div. I code "N~iclearPow9 Plant Components." Article XI-JO(tO.

CHAPTER SEVEN

2. ASME Scc. VIE!, Div. I code. "Design of Ranged Joints," Apgendix 11.

1. ASME S I C I!!. Diu. I code. "Nuclear Power Plant Components." sulnec~ionNC-3M8 (summer 9 979). ""Range Qualification Program," Tsnncssce Valley Aurhoriry. 5. ANSI B 16.5. "'Steel P i p flanges and Ranged Filiings" ( 1 977). 6 API 605. ReaArmed in 1973. "Large Diameter Carh,n Steel Ranger *' 4.

PIPING CONNECTED TO NONROTATING EQUIPMENT

The external loads imposed on nonrotaling equipment by piping should be h l o w the allowable loads supplied by equipment manufacturers. Examples of nonfired equiprnents are hear exchangers, tanks, pressure vessels, drums, air coolers, and condensers. Examples of fired vessels are b i l e r s and fires healers. The actual forces and moments from piping stress analysis may $a: sent to manufacturers to gel these loads approved. .The methods lo calculate local stresses on the vessel and nozzle intersect iota arc: I. Finite clement analysis that is more accurate but could be expnsive

lor ctrrnpuler resources. Local stress calculation outlined hy Welding Research Council (WRC) bulletin 107 (reference I). 3. Local stress calculations using Fliigge-Conrad solu!ions (relerence 2). 4. W R C bulletin 297, (reference 8) Local Stress in Cylindrical Shells, supplement lo W R C bulletin 107.

2.

For each piece of eqt.ipmenl, applicable code and standard requirements should be satisfied, Instead of reprinting text information available from other sources, a discussion with specific examples lor cylindrical and spherical vcssels is presented here. .

LQGAL STRESS GALGULCaTIOM USiCIIO W G "107 BULLWIN Based on work done by Bijlaard, W R C IOWwas prepared. Sign conventions used are exactly as given in the bulletin.

8.

Vessel (cylindrical) diameter to vessel thickness tatio range is 80%DIT 600. I 2. Nozzle diameter to vessel diameter ratio range is 0.02 5 d/D s 0.57. 3. Ncaazle thickness is nor considered For cylindrical vessel. 4. Nondirnensional constants read From curve From W R C 109 bulletin are for acceptable ranges only. Extensions of curves can he used only if aliiowed. Values outside the range may give unconservative resulls. 5. March 1979 revision of the bulletin gives important revisions. Earlier versions should Re carefully used. 6. Signs lor stress were obtained by considering the deflection of shell resulting from the various modes of loadings. Tensile stress is masked as + and compressive stress is marked as -. 7 . Maximum shear theory has k e n used to delcrmine stress intensity, 8. Welding Research Council 107 omits rhe internal pressure stress. The sflecl of pressure may be included if desired. 9. The stresses calculated are in the vessel wall (shell) an&nof in the nozzle. Stresses may be higher in the nozzle wall in case the nozzle r~peningis not reinforced. 1 0 , Welding Research Corbncil 107 method may be used for ellipsoidal Reads as well as cylindrical and spherical shells. I I. Stresses due to radial load in cylindrical shells are not applicable if the length of the cylinder is less than its radius. The curves are for length radius ratio of 8. 82. Stresses due to external moment are not applicable if the attachment is located within rhe distance of hail the shell radius from the .near end of the wali.

Table 7.1 gives stress concentration factors K, and K b . The equations for calculaling the stress concentration factors K. and K , are given in Eqs. 7.1 and 7.2. Table 7.1 was generated using Eqs. 7.1 and 7.2. The actual stress calculated is compared will1 the allowable stress. i f the actual stress is higher, a pad thickness is assumed and the calculation is rerun with the total thickness (sum ol vessel and pad thickness) as vessel thickness. In practice, the assumed pad thickness is equal to the vesse! thickness. If double the thickness is not enough, efiorrs may k made to reduce the loadings a n the vessel.

w(,cre r = radius used for nozzle-to-shell interlace (in.) and ~\c..;s

T = shell thick-

(in.). TABLE 7.1 Conrenlmallon Fsrlom (Besed on :-in. rrrdius at skit-lo-mzzle inler(rce9

T tin.) > I4

I lh

;

K,

Ko

1.5121 1.5661 1.6574

1.2899 9.3280 6.3650

1. Calculate the local stress lor the cylindrical vrrsrl given as. follows (reference 1): Vessel radius = R, = 72 in. Vessel thickness T = 0.4375 in. Attachment radius r, = 3.125 in. Geometric parameters are:

' s.rP.--nCerh..-.~dn fa~autrare l o r the membrane load K the knding load & = IJJ. The applied loads are: I Radial load F = -97.8 16 -. crrcrllar moment Rb, = -968 in.-[b Longitudinal moment M, = - 10,152 Torsional moment M, = 3 1.368 Shear road V, = -4 Shear load V , = -45 1

2. Calculate local stress lor the spherical vessel given akAllowr: Vessel rnean radius = 16'7.43in.

The nondimensional constants read fmm graphs of WRC 107 are: WRC 107 Graph

Vessei thickness =: 1.125 Nozzlethickness =0.5 Nozzle rnean radius = 11.75 Nozzle outside radius = 12 The applied roads are: = p = 1377 ib Radial load = V ,-- 97 Shear load Shear load = 0/, -36 Overturning moment = M I= - 0 58,808 in.-lb Overturning moment = M2= -47,996 Torsional moment = MT =. - 10,344 The concentralion factors are: K, 2.0 and Kg = 2.0, The geometric parameters are:,

-

-;

Nondirnensional constants Iron; W R C 107 graphs are as follows:

In an eFTorr lo extend WRC: 107 results lo larger DIT and smaller dlD valves and lo include the effect of the nozzle thickness, calculation using FlGgge-Conrad solutions is presented (reference 21. WRC Bulletin 297 (reference 8) broadens the coverage of WRC Bulletin 107 and is based on Steele" theory (relerence 2). WRC 297 includes the L


O.I

Figure 10.1 Fig. NC-3673.2tbr-2, &c III

1

1.0 forBush weId 1.(3 for =-welded

1

2.1

'i

C

Fact-wlded joint, socketwelded Bange, or ing1ewelded slip on Range

Fig. 1\1(2-3673.2(b)-3, sketch= (a). (b), (c), (6)and (I)

sketch (dl

---

/-

i .-

30" tapered nransi~on (ANSI BL6.25) (1)

Corecen~creducer

( m S I B16.9 or MSS SP48) (7)

--

*e;d$ed p r p jmnl or tku@AzcdedRange

--

I

2.3

or corngated or cm-d

&a,

R - W d m o f e l W 0 f p kX ~% m. %

k;o;D bbobv,

,

_*

e

b

b b b b

r

_

-

C

*

IcN

C

_

)

_

b b '

)3

C r p l M L -

h)

* \ D O 0

p p t x , ~ ,

. . - - w -

";;hi%&

E

-%

0

-

6

TnrPLe

*S

Z

(can?~iaw) .

Iw Met*

iiaT

P

-

34 Ni

M33

9B

3

-

-

341 M 1 C r 4 Pli-CwdU 21 Ni

A334 M33

9B

3

-

4

4

A333

9A

7

9A

7

-

24 Ni 9 Ni 9 Ni 2 N c ~Cu 2 ~ i - -eu l

A334

M33 8334

9A

9

oA

9

Cr-f Mo i C r 4 Mo 3 er+w 5CdMeSI

M35

3

PI

M35

3

Ir2

~335

5

AS35

5

~5 P5b

a 3 5 A334 -35

5

B5c

5 5

P7

A335

4

A335

4

PI 1 81 2

5 Cr-+ %Ti 7 Cr+ Mo 9 61-1

Mo

If C r d Mo 10 - 4 Mo

a 3 3

11A-SG1

8

a34

B1A-%GI

8

P9

-

-

-

-

-

SE,KS?!

Min. Tensile

Min. Yield

65.0 65.0 M,0 65.0

35.0 35.0 35.0 35.0

-

65.0

35.0

-

100.0

75.0 75.0 46.0 46.0

69 69

30.0 30.0 30.0 30.0

3

1m.O 63.0 63.0 55.0

55.0 M.O (iO.0 60.0

-

50.0 60.0

-

50.0 Mt.0

30.0 30.0 30.0 30.0 30 1 )

-

-

-

-

-150 -150 -150 -100

21.7 21.7 20.0 21.7

-100 -320 -320 -100 -100

21.7 31.7 31.7 21.0

21.0

-

-20 -20 -20

18.3 18.3

18.3 18.3

-20

20.0 20.0

18.1 18.1

-20 -20 -20

20.0 20.0 20.0

18.1 18.1 18.1

,

19.6 19.6 19.1 19.6

19.6 31.7 31.7

-20

20.0

18.7

I

0 I

18 7

* , a m . -

4.4y.4

-c$...

- b - . c - . C -

4 m m b o b

-,-,+-I4

i n o ~ n u lk k k k

raw Ce--NNcc-.h)=-'h) I J P I y ? ? J ? J +Pppppp wln rD * W c n I n u , - * 4

PI.

.*

I

I

* , . d e w

-.-

b i 3 b b b b

I

. . C P

C

C

C

M

L L : ~::g W

W

W

N

Q.O.QI0.

b i b

g z t g

N N N N C )

~O.rncr.P,

2

,

-

- F C C J F -

p + p - m

$fa

I

-4w-3-4

4

L - C C - C

-1pp p p p p chcnul.-4 4 c a o o m + + - a *

i

a

h

i

b

-0

w w m m cnmV3.Q.

I

k-4-4

- - - . - - - -6

I

I

d

"I

g

e( r ea me e e e e e z z e .Dee

eirmcr * a * *

a-.irmw

eeee eeeeeeee eeeeeeee

U

W

W

W

- m V , u l

W W W W L a ' A V I *

W

W

W

M m - X

W W

W

P

W W

W *

W

W

W

W

w w a w

30.0

23

25.0

-

30.0

20. 23

30 0

61. 20

30.0

-

30.0

ha. 20

30.0

-

30.0

ha. 20

16.5

-

-

16.21 11.6

-

-

18.0 18.0

17.5 17.5

-

I

11.1

10.4

-

16.9 16.2 16.9' t6.2

15.1 15.1

-

-

-

-

-

-

-

8.4

6.4

4.4

2.9

1.8

1.0

-

-

-

9.6

-

-

-

-

-

-

-

-

-

-

13.0 13.0

6.8 6.8

4.5

-

-

-

-

-

-

-

4.5

-

-

-

-

-

-

-

-

A268

I l C2bTI Tuk

A268

13 .. Cr Tub

A268

A268

16 Cr Tub 18 Cr-Ti Tub 20 C r x u Tub

A268

2 K r Tub

A268

Tuk 16 Cr-12 NG-2 M Tubes

18 C r 4 Ni Pip I 8 Cr-B Ni P i p 18 Cr-8 Ni T u k , 23 Cr-12 Ni PIP 24 C-20 Ni Pip2.4 Cr-20 Ni Pip

16 0 - 1 2 Ni-2 Mo

Pips 16Cr-12 NC-2 Mo Pip 16 Cr- t 2 Ni--2 Mo

Ryes 18 Cr-13 Mk3 Mo

m=

18 Cr-10 N f l i

Rpe 18Cr-10Nf-Ti

EF

'2

-

i I

1

44

2 Q

N

0

a

N

tJ

N

N

0

8

b 0

o 0 O C O P

b

U

Q

0

b 9 0

0

b

N

N

N

k,

9

b P Q Pb 0

0

N

N

N

N

8 % 8 3 % P

h

p

Q

,

b

p O

b

o i

,

p B

i5 3 1 5 ~3 .F

XXS

XS

80

80s

l(tO

XXS 5S 1" 1.315

Srd.

XS

40 80 1@

~t

Srd.

xs

40 80 160

, -

XS

40 80 160

0.431

0.065

0.057

1.185 1.097 1.M9

80S

0.179 0.250

0.157 0.219

0.957 0.815

0.639 0.836

0.0448 0.0527

0.0853 0.100

3.2 1 15.1

0.0579

0.1 10

26.9

0.0500 0.0757 0.0874

0.076 0.115 0.133

0.1M 0.125 0.141

0.161 0.190 0.214

0.358

0.313

0.5W

1.08

5S 10s

0.M5 0.109

0.057 0.095

1.530 1.442

0.33 0.53

405 8%

0.140 0.191 0.250

0.123 0.167 0.219

1.380 1.278 l.lBO

0.67 0.88 1.11

0.382

0.334

0.896

1.53

0.242 0.284 0.341

0.%5

0.057

1.770

0.38

0.158

0.104

0.161 0.195

0.321

1.47

0.304 0.284

1.9

0 187 0 a28

2.44

O

2 .(K7

0.543

0.W

0 178

3.60

0.428 0.420

I .a 1 .M

O

0,407 0.387

2.11

61311

10.58

0 226

18.76

0.361

2.84 3.M

0.125 0.193 0.235 0.291

1.23 2.17 2.91 4.25

0.56 0.55

1.11 1.8 1

0.80 0.7 1

0.54

0.65

0.342 0.411

6.04 11.2

0.51

2.27 3 .MI 3.76

0.47

5.22

0.27

0.166

4.5'7 6.66

0.46

1.27

1.07

0.58 0.55

0.96 0.8< 0.77 0.61 0.4 1

0.82 0.80 0.79

1.60 2.64 3.65

1.72 1.58 1.45

0.61

0.247

0.260

1.63

40s 8OS

0.145 0.200 0.281

0.127 0.175 0.246

1,610 1.501) 1.138

0.80

0.326 0.412

1.43

0.310 0.391 0.483

0.400

0.350

E.lW

1.89

0.568

0.598

2.26 3.32 5.15 8.53

0.065 0.109 0.154

0.057 0.095 0.135

2.245 2.157 2.M7

0.47 0.78 1.07

0.315 0.4W O.M

0.265 0.420 0.561

0.56

2.05, 2.72 3.43 4.87 6.4 1

1.682

405

0 L29

0.63 0.62 0.6 %

0.005

0.508

m

o 394

0.65

0.109

1.07

0.52

W

0.927

10s

5S 10s 40

0.270

0.570 0.718

0.005 0.116

XXS

Std.

0.308

0,434

0.109 0.133

5s

Srd.

0.742 0.614

10s 40S

XXS

1.m

0.135 0.191

0.255 0.4 13 0.494

XXS

1.-

0.154 0.218

0.585 1.02 1.50

a

Modulus Ana

kh

hb

(=g 8) iwb

Bend

imk

D

XXS 5s

Jp 4.W

Sd.

48

XS

$80

4s BOS

XXS SS

4"

Sllf. XS

4.5m

40 80

IOS 405 80s

120 1(10

XXS SS 18s

g* 5.563

Sa"

190

4°C:

XS

80 I20 1U

8m

XXS

0.500

0.525

2.300

0.83 0.120 0.226 0.318

0.073 0.1% 0.198 0.278 0.551

3.834

0.074

4.334 4.260

0.636

0.083 0.120 0.237 0.337 0.438 0.531 0.674

0.105 0.209 0.295 0.382 0.465 0.5W

0.109 0.134 0.258 0.375 0.5W 0.625

0.095 0.117 0.226 0.328

0.750

0.655

0.438 0.541

Glrrurrcterntic per Unit

3.360

3.548 3.3a 2.728

4.026

3.826 3.624 3.438 3.152 5.345 5.295 5.047 3.813 4.563 4.313 4.Mf

sq. i n e b a

1whes4

rnehes3

R&iw

of Gyr%aon

plpe

Ware-

*

Baigmrian WW %Mule

Average

Wall

mwn Wall

Thick-

Thick-

Mmkr

e m

inches

D

I

SIFT.

XS

v

1

10.750

Inside Dimefer

Crasshrionsl Me@ hea

Mornen1 of Ineda

Section Mdulus

M

kk

XXS

Mini-

c

Weight o f

terisric

OR Cijrrcr-

RF

p r URir

lion

Wawr

k e l ir r d

( 41 )

inches

Radirss

Fled C h c -

irxbes

sq. ineba

d

A

imkA I

1mkeJ3

Z

Radius I Ift hiR

inch

3

Ib per er

W,

Sb per

It

TABLE A4 (Cd~~ithaKdD

rnm

DmperUrut

Area e m

&on

13End Rdrus

llF99,

neSJ

lrnAes

m c b

inches

sq. tnches

tnches*

incha3

f

a,

d

A

1

Z

i="\ ,". 1

lltt hiR

inck r,

W~

tb per It

W,

Ib per It

Aver-

Mini-

Inside

mum

Dim-

Modulus

mck-

Ihiek-

inch

ineb

inches

inches

D

I

5*

d

sq. inch= A

10 20 30 40

0.250 0.375 0.500 0.593

0.219 0.328 0.438 0.519

18.580 19.250 t9.W

15.5 23.1 30.6

i 110

18.814

16.2

1700

0.%7 0.655

60

0.625 0.750 0.812

0.711

18.750 18.569 18.376

38.0 45.4 48.9

80

0.875 1.031

0.766 0.902

18.250 17.938

100 120

1.281 1.50

1.121 1.313

17.138 17.000

( 4tf

Srd. XS

20"

ZO.C>OO

I40 160 kd.

10 20

XS 30

inches4

I

iocks3

Z

C b c -

per Ullit Wnd

tion

Radilu 11ft k/R

inches

3

ra

Ib wr L1

75.7 I II 146 170

0.01 !: 0.W7 0.W3

6.98 6.94

0.076

1790 2 10Q 2260

179 210

0.080 0.m7

226

0. I 0 6

52.6

1410

241

0.115

61.4

2770

277

75.3 87.2

3320 3760

312

757 1460

37.6

52.7

- ww Ib per It

129

78.6 104

126

6.86

123

120

6.85

I20 117

6.79

129 154 166

6.77

179

0.138

5.72

209

113 109

0.175 0.210

6.63

256

6.56

296

6.90

6.81

121

115

103 98.3

1

%

1

corr;iision allowance = 0.10 in. The design pressure is SO0 psig at 700°1:. is Ike design adequate for the internal pressure? I

Solurion: 7 he allowable stress values from Appendix A 'I'able B.3 1.1( A p p c ~ d i x,431 are: for pipe, SE = 14.4 lisi; for ring, SE = 14.4 ksi.

Th= (0.500)(0.875)= 11.438 in.

i

5d

-.

.,. r Gal--.--on%l ~ . 4 n ~ hb.-,

4

I 1'

....art - ,.I* 24, "

design cojldilions are 350 psig art 4tKPF. I t is assumed that the piping sptcm is to remain in service until all metal thickness, in h r h branch and Reader, in excess of that required by Equation 2.1 has corroded away. What reinlorcing is required lor this connection? Soiution : The allowable stress value from Appendix A, Table 1 of B31.3 (Appendix A31 is SE = 16.0 ksi.

T, = (0.281))(0.875)= 0.245 in. I

r, = 0.500 in.

(350)(8.625)

' -- (2)(16,000) + (2)(0.4)(350)= 0.0W5 in.

L4= 2.5(0.0245 - 0.10) 3- 0.500 = 0.8625. This is greater than 2.5(0.4.3W- 0.lO) = 0.845 in.

h

-

(350)(4.50)[)) = 0.1)4NX in. ( I ) (I6,oOo)+ (2)(0.4)(350)

d , = 4.500 - (2)(0./1488) = 4.402 in.

Reqr~iredreinlorcing area, A , = (1).0W5)(4.402) = 0.4 12 sq. in Try fillet welds only

- 0, 10) 0.335 6.625 - 2(0.245 ---- - - -- - = 7 . 1 15 in dz = d , = sin 61)" 0.866

= (2.5)(0.0933)= 11.234 in.

Or

I ,.fl'he required area, A , = (0.274)(7.3 15)(2 0.866) = 2.27 st4 in. v

(2.111)

'fhe reinforcement area

in run wall, A2

= (1.4tlXscl.

= (7.3 15)(0.438- 0.274 - 0. IO)

in. (2.12)

in branch wall, A3 = (2) 0.R45 -(0.245 0.866

(2.5)(0.04NH) = 0.122in. use 0.122 in. Due rt3 limitation in the height at the reinforcing zone, n o practical fillet weld s i x will strpply enough reinforcement area; therefore, rile conneclion must he reinforced hy a ring. T r y a ring of 64 in. 0.D (measured along thc run). A~.;rrmcthc ling l o be cut from a picce o l NPS W Schedule 40 API L (iradc A scamless pipe and welded to the connection with minimum size lillcl welds Min. pad thickness, 1, = (0.322)(0.875)= 0.282 in.

New I,,

.in ring, A4

or (2.5)(0.0935)

= 0.281 sq. in.

in fillet welds, A, = (4)(4)($12 Total reinforcement area

+ 0.282 = 0.404 in.

= (2.5)(0.04138)

= 2.986 sqiin.

X, = 0.234(6.25--4.5) = 0.4 10 sq. in.

Leg Dimension of Weid: An NPS 8 sun (header) in a n (311 piping system has an NPS 4 branch at rlghl . n r n

f2 U.

1

I

A 0

A D C P I SI

4'

a

n

,,,,!

use 0.234 in.

Reinforcernenl area in the sing (considering only the thickness within 14):

This total is greater than 2.27 sq, in., so that no additional reirrforcement is required.

i n n l r r (Fin A I \ O a r ~ t RnGonr

= 0.234 in.

I *

Reinforcement area in Gllel welds:

I

X2= (2)(4)(0.228)~= 0.052 sq, in. Total Reinforcement Area, A4 = %( C X2= 0.462 sq. in. This total reinforcement area is greater than the required reinlorcirrg area; therefore a reinforcing ring of (43 in. O.D., cut from a piece of NPS H Schedule 40 ABI 5L Grade A seamless pipe and welded ao the connectictn with minimum s i z fillet welds would provide adeqrraae reinforcing lor this connection.

An MPS 14 3 W Ib forged steel socket welding coupling has been welded at right angles lo an NPS 8 Schedule 40 header in oil scrvice. The header is AST'M A53 Grade B seamless p i v . The design pressure is 400 psi and the design temperature is 450°F. The corrosion aliowance is 0 . l O in. Is additional reinforcement required? Sod ("ion:

Nkf Since branch is less than NPS 2 (according lo 8 3 1.3 Section 304.3.2(h)) the design is adequate to sustain the internal pressrlre and no ealctrlarions are ateeessrery. It is presumed, of course, rhar calculations have shown the run p i v 80 Lo satisfactory for the service conditions acscprding to Equations 2 . l , 2.3 and 2.4.

INDEX

Accelcralion. 35. 133 Active valves. 133. 181 Allowable deflection, 35 Allowable load. 126 AIlowable momrnl, 102, 109 Allowable span. 34 Allowable stres.c, 2. 50, IBO, 212 Allowable %trc.ir, range, 13, 50 Allowable working pressure, 25 Allowance. 22 Alloy steel pipe, J Aluminum alloy pipe, 9.40, 132, 139, 2 0 4 Anchor: dircc~ionalanchor, 93 in~ermedia~c anchor, 92 main anchor. 9 2 movcmcnl. 4. I87 ANSI coder. 49 ASME code, Scc 111.49. 171 ASTM standard$, 4 Atmospheric pressure, 135 Austenitic s~ccl,6. 202 Average gradient. 37

.

Rack fill. 146 Ball joints. 92 Beam, l8J Bellows, 10.92. 181 Rending effect, 14 Bending stress, 14, 18. 73, 144 Bends. l I , 95.57, 172, 198 Bevel edged. 8 Bijlard'r curves. 107, 10") Blank thickness, 25 Bolt circle. 102 Roll preload. 102 Rowing, 144 P 'CP 4 I

Bronze, 204 Bumper, 12 Buried piping. 148

Cap, 199 Carbon steel. 202,210 Carbon steel pipe. 3, ~ 1 , 2 0 2 , 2 1 0 , 2 8 2 Casting quaiity factor, 23 Caqc iron material. 2. 204 Centrifugal compreqsor. (28 Crntrtlugally cast pipe, 217 CenrriCugal pump, I29 Check valve, 8 Chemical composifion. 4 Class 2 (NC) piping, 180 Class 3 (ND)piping, 171 Closed space miter. 57 Codes: ANSI code, 49 ASME code, 171 B 31.11 code, 72. I33 RJl.3code.53 B 31.4 code, 146 B 3 I .B code, 49 chemical plant code. 53 gas @ransportation code, 49 liquid transporration code, 146 nuclear code, 171 power piping code, 133 refinery code, 53 Code stress. 72, I80 Cwfficient of expansion, 5,902 Coefficient of friction, 145 Cold moclulus, 19 Cold reaclion, 79 Cold sltring, 76. I B I C k n rrt ! r I

Cone angle, 176 Conslant efforl supgort, I I Conrainmenl prasure movement, l 8 l Content weight, 4,35. 39,226 Conlraclion, 4 Copper alloy piping, 4, 132, 141 Corrosion allowance, 4,7,28 Corrugated piw, 11,@, 92, I75 Couplet. 193 Coupling, 193 Crwpelfect, 132, 165 Critical span, 34 Crotch thickness, 61 Cycles, SO, 52, 171 Cyclic condition, 3 Cylindrical vessel, l i l , 114, 159 ramping device, II h a d load, 4, 182 h:ad weight, 1, 50 @efleclion,34 Densiiy, 5 , 19 Design basis accident, 181 Design loads, 171 h t i g n pressure, 26 Diameter, 226 Displacement ssrain, 50 ()isroriion. 50 Orainage. 37 Dresser coupling, 92 Dynamic load factor, 136 'Dynamic loads, 4, 102, 141 Ductile material, 1 , 204

,

"langed elbow, 60. 176 Flangedjoint, bn. 101 Flexibility, 7, 10 Flexibility characterirlics. 57.68, 172 Flexibility factor, 57.61, 172 Flexibilily stress, 72 Flexible joint, 92 Flow friction, 4 Fluid flow, 2 1 Force, I Formal analysis, 53 Frictional resistance. 146

I.atrolet, 1%). 192 I.cakage at flange. 7 I.imir slop, 12 l ivc ioad, 4 I.oad coefficienl, 147 I.oadingon pipe. 4 I.OCA. 102 Iocal stress. 109 I.ongiludina1strew, $0, 146 I.ong radiuc elbow, 62 I.oop. 10.68.82, 84, 85, 89 Manufacturingtolerance, 22, 28 Markl equation, 56 Mass type insula~ion.38 Malerials for piping. 3 Maximum strain theory, 144, Metal area, 10.226 ftl~ralbellows, $4 Metal hose, 92, 9") Metal weight, 35, 226 Metric units, 132. 167 . Mill tolerance, 33 Minimum thickness. 22 Mi.rma~cll,I45 Miter bend, 26, 30, 57-63, 172 Miter space, 64 Mode, I83 Modulus of elasticity, l. 5,210 Mod~rlurof