Wrc 329-1987 Accuracy of Stress Intensification Factors for Branch Connections_part4

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Section 4 . ~ ) . : 3 presents evidence that K

2

b is likely to be

around 2.0, not LO. On the other hand, the calculated

stresses are based on intersecting shells with no fillet

weld or radius. These stresses attenuate very rapidly,

sometimes by 50% within one wall thickness. In fatigue

test models, the fillet weld or outer fillet radius may

cover this high stressed area, and thereby significantly

reduce the

actual

stresses as compared with the calcu

lated stresses. Further, the fillet weld or outer radius

may provide reinforcement in the critical intersection

zone.

In

the sense

that

protection against fatigue

is

the

rationale behind

the

Code evaluat ions using i-factors,

we view

the

fatigue test s as more directly relevant

than

calculated stresses. We

thus

view

Table 15

compari

sons as

an

adequate basis for the proposed

i

for

RIT

up

to about

25. (Note

that the

maximum

R/T

in

Table

14

is 18.2.)

Based

on all present evidence, we

think

it is

reasonably valid for R/T up to 50.

As

a final

point,

note

that

i

covers the full range

of

r/R;

hence,

the

UFT can be deleted from Fig. NC-

3673.2(b)-1.

Indeed, if

it

is

not deleted, the underesti

mate of

i

for Mob would

remain

in the Code.

6.0 References

1. Mark , A. R. C. and George, H. H.,

"Fatigue

Tests on Flanged Assemb·

Trans ASME,

82,77-87, (19 )0).

Mark ,

A. R.

C.

"Fatigue Tests

of

Piping

Components,"

Trans. ASME,

74,287-303, (1952).

3. ANSI

B3Ll,

"Power

Piping,"

1983 Edition, ASME, New York.

4.

ANSI B31.3, "Chemical

Plant

and

Petroleum

Refinery Piping," 1983

Edition, ASME,

New

York.

5. ASME

Boiler and

Pressure

Vessel Code, Section

Ill.

Division l.

"Nucle

ar

Power

Plant Components," 1983 Ed. with Winter 1984 Addenda, New

York, NY 10017.

6. Blair,

J.

S.,

"Heinforcment of Branch

Pieces,"

Engineering,

London,

England, 1947.

7. Pickett, A.

G.,

et al.,

"Low

Cycle Fatigue Testing

of

One-Half Scale

Model

Pressure

Vessels," Progress

Reports

No. 9-12.

Southwest

Research

Institute, San Antonio,

Texas, July 1964-.Jan. 1965.

8. Decock,

J.,

"External

Loadings

on Nozzles in Cylindrical Shells.'' 4th

lnt'L

Conf.

on Press.

Vessel Technology, J. Mech. Eng., 1980.

9. Davies, J. B. and

Jaske.

C. E. "Fatigue Evaluation of Weldolet Branch

Connections

in

Carbon Steel Pipe," Battelle-Columbus Report

to

Bonney

Forge, Allentown, PA 18105, Aug. 30, 1974.

10.

Tableriou,

J .P . and Walsh, D .,

"Determination of

Stress Intensifica

tion

Factors

for

the

Code

Qualification

of Integrally Reinforced

Branch

Con

nections," ASME Paper No.

78-PVP-66

and "Final

Report

on 1979 S F

Testing Program.''

Target

Technology Report

to WFL Inc.,

Houston, Texas

77008, Aug. 22, 1979.

11.

Forte, T. P.,

"Fatigue

Evaluation

of 6 x 4 Weldolet Branch

Connections

in

Carbon

Steel Pipe," Battelle-Columbus Report to Bonney Forge, Allen

town,

PA

18105, Dec. 31, 1981.

12. Davies, K.

B.

and

Jaske,

C. E.,

"Fatigue

Evaluation

of

12 x 6

Weldolet

Branch Connections

in

Carbon

Steel

Pipe,"

Battelle-Columbus

Report

to

Bonney Forge, Allentown, PA 18105, June 25, 1975.

13.

Forte, T. and

.Jaske, C. E.

"Fatigue

Evaluation of

14 x

6lnsert

Weldolet

Branch Connections

in

Carbon

Steel

Pipe,"

Battelle-Columbus

Report

to

Bonney Forge, Allentown, PA 18105, Apr. 30, 1981.

14.

Rodabaugh,

E. C. , "Cycl ic B<?nding Tests of a Half-Scale Model of

an

8"

x 24"

Saddle Reinforced Branch

Connection,''

Tube Turns, Report

No. 8.011,

Louisville, K Y 40201, 1953.

15. Mershon, J. L., Letter to member of PVRC

Subcommittee

on Rein

forced

Openings,

Dec. 20, 1963.

16.

Schneider,

R. W.,

Letters to

C. R. Felmley, .Jr., Executive

Secretary of

PVRC,

Mar. 17, 1981, Mar. 31, 1981 and Apr. 10, 1981.

17.

Schneider,

R. W., Letter to

,J.

Millman, Secretary of ASME Section III,

Apr. 21, 1981 (copy to B31 Code Committee on Pressure Piping).

18.

Khan,

A. S.,

"A Study of Fatigue Crack Initiation and Failure

in Rein

forced Shell to

Shell Intersections,"

U. of Oklahoma, Report Prepared for

WFI

International, Houston,

TX,

May

1985.

19.

Lankston, R. J. (Taylor Forge

Engineered

Systems,

Inc., Paoli,

KS

6(l071)

Letter to E.

C.

Rodabaugh

dated May 30, 1985.

20. Mershon, .J. L., et al.,

"Local

Stresses in Cylindrical Shells Due to

External Loadings on

Nozzles-Supplement

to WR Bulletin No. 107,

WRC Bulletin 297,

New York, Aug. 1984.

21. Fujimoto, T. and Soh, T.,

"Flexibility

Factors

and

Stress Indices for

Piping

Components with D T > 100 Subjected to

In-Plane

or

Out-of-Plane

Moment,"

pp.

59-70 of ASME Bound

Volume No.HOO:J29

of Pressure

Vessels

and

Piping Conference, New

Orleans,

.June 1985.

22.

Wordsworth, A.

C.

and Smedley,

G. P.,

"Stress

Concentrations

of

lin

stiffened Tubular Joints,"

European

Offshore Steels Research Seminar, Cam

bridge, 1978.

2:l. Moffat, D. G., "ExpNimental StrP" Analysis of J FabricatPd Equal

Diamc·ter

Branch Pipe Intersections Suhj('('t('(l to Moment Loadings," 'roc.

lnst.

Mech.

Eng . Part A.lsstt<: A4.

24. Wkhman, K. R.

HoppN.

A. and Me"hon . . L., "Local

Spherical

and

Cylindrical Shell> Due to

External

Loadings,"

WRC

/07

NPw York. Aug.

19hfl, ""'ised Marrh 1979.

2f>. Corum,.). M . et a/ "TheorPtiral and Experim<•ntal Analysis of

OHNL Thin-Shell

Cylinder to-Cylinder-Model No. 1

2,

:l, ·ll. OHNL-TM

4:,5:l, fJ021, G020 and f>OJ9 for ModPls I, 2, :

and

4, respectively. Dated Oct.

1972, Oct. 197fJ, ,Jltne 1975

and

,June 197;, for Models I, 2, :land

4,

respectively,

Oak Ridge National

Laboratory,

Oak Hidge. TN

:mno.

26.

Hodahaugh, E. C.

and Moore, S. E.,

"Stress

Indices and Flexibility

Factors

for Nozzles in

Pressure

Vesspls

and

Piping," NUREG/l'H-0778,

Oak

Hidge

National Laboratory,

.June 1979.

27.

Rodabaugh, E.

C.,

"Compari,ons of ASME Code a t i ~ u e

Evaluation

Method

for Nuclear Cla8s

1 Piping with

Class

2

or

3 Piping,"

Nl1HEG/CR

:)24:l. Oak Hidge National Laboratory, .June 1983.

28. Rodabaugh, E. C., "Sources of Uncertainty in the Calculation of Loads

on

Supports on Piping

Systems,"

NUREG/CH-3599, Oak

Hidge National

Laboratory,

.June 1984.

Appendix A-Specific Recommendations for NC-

3600 of

ASME

Code Section III

The

last pages of this Appendix include copies of

pages 166, 171,

172, 173

and

17

4 from NC-3600 of the

ASME Code, Section III, 1986 Edition. Pages

166, 171,

172

and

174 are marked-up

to

show recommended

changes.

Table A1

contains

the

recommended notes to

replace those on

p.

173.

The changes include those in Section 5 of this

re-

port. We will discuss those first in

the

following. In

addition, several more-or-less editorial changes tooth

er portions of Code pages 171, 172 and 173 are suggest

ed; we discuss those subsequent ly in

the

following. To

facilitate the discussion

of

changes, we have numbered

the

"Descriptions" from (1) to (15) as noted on the left

margin of Code pages 171 and 172.

Changes From Recommendations in Section 5 of This

Report

Page

166

This

change reflects Recommendation

IOc).

This

change makes the procedure the same for Descriptions

(4), 5)

and

(7); and eliminates

the t ~ / T r )

term in the

i-equation for checking the branch end of Description

(7).

We have changed

Tb

t o ~ as being consistent with

page 174. We have

not

changed

Tr;

it agrees with page

174

but not

page

171.

Description (4),

Welding

tee

per

ANSI Bl6.9

The only change

is

replacing the meaningless" 1"

by

"Note (9) ; see Recommendation

1).

Description (5), Reinforced

fabricated

tee

The "Description" has been retitled to "Fabricated

branch connection "

rather

than

"tee."

This is mo-

tivated by revised footnote (7), which is applicable to

"Fabricated branch connections "; Descriptions

5)

and

7) not "Welding tee "Description (4). The "1"

has been changed to

"Note

(9)."

I t might be noted

that

the run moment problem

continues to exist for Description (5). For example,

consider a 24 in. diam x 0.375 in. wall run pipe with

4.5

in. diam x 0.237 in. wall branch. For a pad or saddle

with te = 0.375 in., the SIF i =4.57. Using Description

(7), which, of course,

is

without a pad,

i

=

2.1

(lower

bound,

r2

not provided). Perhaps the

Mob

problem also

exists.

36

WRC Bulletin 329



Description (6), Unreinforced

fabricated

tee

Deleted, See Recommendation (lOd).

This

De

scription is included in Description (7). Retention of

Description (6) would, of course, continue both the

M

0

t>-problem and the run-moment problem.

Description

(7),

Branch connection

The Description has been retitled to make

it

con

sistent

with

and

distinct from Description (5).

The equations

for

i are from Recommendation

(lOa). Note

that

they are written for

r2

not provided;

i.e., as-welded. For the branch end, when

the

value of i

is not controlled by the minimum,

the

equations for i

reduce the value by a factor of 2 from

the present

rule.

They reduce

the

minimum for

the

branch end from the

present 2.1 to 1.5.

For the run ends, there is no change from the

present rules.

The

factor of 2 in the present footnote

(6)(h) leads to the coefficient 0.8 rather than the

present 0.4. The present minimums of 2.1 for rz not

provided

and

1.5

for

r

2

provided are retained.

However, Description 7) is no longer limited to

r/R

0.5. For

r/R =

1.0, the SIF equation for branch ends

becomes essentially identical to the present i =

0.9 R/

T 213; the difference lies in the r/rp) factor. For r/R =

1.0,

the SIF

equation for run ends becomes 0.8 R/T)213

rather than

the

present 0.9(R/T)213.

There

is a subtle but usually numerically insignifi

cant

change in that Z for run ends and for full outlet

branch connections is not defined as 7r Rm)

2

r or

1r r

2 T ~ . To the extent that a Code user takes

Z

to be

the

exact section modulus, he will have a

bit

higher

calculated stress than if he used the approximate sec

tion modulus.

Present Note

(6)

Part

(a) has been dropped because

it

is

not

neces

sary

and because it implies that branch connections

that

do

ot

meet NC-3643 are somehow acceptable.

Parts (b)

and c)

are picked up in proposed note (7);

applicable to both Descriptions

5)

and (7).

Part (d) has been dropped because moment fatigue

tests

and

theory indicate

that

the inside corner radius

is

not

a critical consideration.

Parts (e) and

h)

have been combined in proposed

note (8).

Part

f)

has been dropped. The lower bound of 1.5

for checking the branch end with

r

2

provided has been

retained.

Part g)

has been dropped because of the D

0

/t

100 limit in the title of Fig. NC-3673.2(b)-1 and be

cause the

r ~ / R

0.5limit no longer applies.

Fig.

NC-3673.2(b)-2, Branch

dimensions

General note

2)

has been deleted; see Recommen

dation

(13). Editorially, an arrow on

rp

in (b) should be

added

and, in (c), the arrow on

rp

should end

at

the

vertical line.

More-or-less Editorial

Changes

to

Fig. NC-367:l.2(b)-l

Note (l)

The

words reinforced thickness were perhaps

meant to be reinforcement thickness but, more di

rectly, te is

the

pad or saddle thickness.

Note

(2)

Proposed footnote

2)

is intended to be the same as

the present footnote

2)

with respect to i-factors. How

ever, the word bending has been changed to mo

ments. See discussion under note 3).

Note

(3)

Proposed footnote

3)

is intended to be the same as

footnote (2) as

it

applies to k-factors for elbows, bends

and miters. However, the word bending has been

changed to

both

in-plane

and

out-of-plane moments

and added: For torsional moments, k

=

1.00. We

think that the word

bending is

meant to exclude

torsional moments; see present footnote (8).

In Description (3),

the

heavy center lines extend

some undefined amount;

an

ambiguity

we

do

not

at

tempt to correct.

Note

(4)

Proposed

note

4) is

the present

note (3), with the

second line deleted. Fig. NC-3673.2(b)-5 (and

-4)

are

deleted in accordance with recent action of the ASME

Code, Working Group on Piping.

Note

(9)

We propose that this note be deleted. Problems with

over-thickness elbows have arisen with wrought steel

elbows;

ot cast

elbows.

Note Tie-ins

The present note tie-ins are incomplete. Note 9) is

not

shown with Description (1). Note

2)

should be

tied into Descriptions (5), (6), (7),

12) and

(13) as well

as

(1),

(2),

3)

and 4); i.e.,

i

1.0

applies

to

all of these

descriptions.

In

the proposed revisions, we have at

tempted to provide complete note tie-ins.

Flexibility Factors

Proposed note

3)

applies

to

elbows, bends

and

mi

ters. Proposed note

9)

applies to Fabricated Branch

Connections and Tees.

The

1 for Descriptions

8)

through (14) is meaningless and should be deleted.

Perhaps a

note

can be developed which indicates the

intent of

the

Code for these descriptions

but we

have

not

attempted to

do so.

Description

(12), 30

deg.

tapered transition

The relevant portion of ANSI Bl6.25 is now Fig.

NC-4250-1.

Description

(15), Corrugated straight

pipe or creased

bend

This Description, Corrugated straight pipe or cor

rugated or creased bend, and the equivalent of

present note (8), are unchanged from the 1955 edition

Stress Intensification Factors

37



of B31.1. At

that

time (and still in B31.1):

Calculations shall take into account stress intensi

fication factors found to exist in components other

than plain straight pipe. Credit may be taken for the

extra flexibility of such components. In the absence

of more applicable data, the flexibility factors and

stress intensification factors shown in Fig. 2 may be

used.

Fig. 2 contained much

of

what is now in Fig. NC

3673.2(b)-1 including Description (15).

Figure NC-3673.2(b)-l, in

our

view, is different from

B31.1-1955 in

that

it

is part

of an enforced

set

of rules.

The

piping system analyses and stress calculations are

subjected

to

checking; which means

that

two or more

readers

of the

rules

must

be able to agree on

the

signifi-

cance of the rules. For Description (15),

it

appears

impossible for ny reader to say

what

the significance

is.

To

illustrate the point, suppose we

put

a single cor

rugation, with depth equal to

the

wall thickness, in a

40 foot length of pipe. Is the flexibility factor of

this 40

foot length of pipe equal to 5?

f

not, using =5 might

make

the piping system analysis (including support

and

nozzle loads) almost meaningless. On

the

other

extreme, in what quant itat ive way is a corrugated pipe

different

from a Bellows Expansion Joint, NC

3649.2?

We have deleted Description (15).

f

a need exists

for this Description,

we

deem it essential

that it

be

quantified so

that

a reader will know what the k 5

and i = 2.5 are applicable to.

Table Al: Revised Notes for Fig. NC-3673.2(b)-1

on

Page

173

(1) Same as

present

note 1) , except

te

=

pad

or saddle

thickness, in .

(2)

Stress

in tens i f ica t ion

factors,

i , apply to moments in any plane and

shal l

in

no

case be taken

as less

than 1.00 except that for branch leg

checks

of welding tees

and

fabricated

branch

connections reinforced

by

pad

or saddle,

i T ~ / T r ) )

1.0.

3 )

Flexib i l i ty

factors ,

k,

apply

to both

in-plane

and

out-of-plane

moments

and

shall

in no case be taken

as l ess

than

1.00.

For torsional moments,

k

=

1.0. The factors apply over the effect ive

arc length

(shown by

heavy center

l ines

in the sketches) for elbows, bends and miters.

(4)

\ ~ h e r e flanges

are attached

to

one

or

both ends,

the

values

of k and i

shal l

be multiplied by the factor c given

below:

(a) One end

flanged,

c = hl /6

(b)

Both ends

flanged, c

= hl /3

But after such multiplicat ion, values of k

and

i shal l not

be

taken as

less than 1.00.

(5) Same

as

present note (4).

(6) Same

as

present note (5).

(7) Fabricated branch

connections:

38

(a) Stress


factors

are applicable only where the axis

of the

branch

pipe is normal to within ~ 5 ° of

the

surface of

s t ra ight

run

pipe.

WRC ulletin 3 9



Table Al.Continued

b) Stress


factors are based on t es t s and/or

theories

in

which the branch connection is

in

s t ra ight run pipe with about

two or more diameters of run

pipe

on each side of the

branch.

The

effect

of

closely spaced branch connections may require special

consideration.

8) Fabricated

branch

connections

other

than

pad

or saddle reinforced:

If

a radius

rz is provided that i s not l ess than

the

larger

of

Tb/2, Tb y)/2 [Fig. NC-3673.2 b)-2 sketch c)] or

Tr/2,

then

calculated values of ib and

i r may

be divided by 2.0; but with

i b T ~ / T r )

1.5

and

i r

1.5.

9) Fabricated

Branch

Connections and Tees:

the

In

piping

system analysis, i t may

be

assumed

that

the f lexibi l i ty

is represented by a

r igid

joint

at

the branch-to-run centerlines

juncture. However, the Code user

should be aware that this

assump

t ion

can be

inaccurate

and

should

consider

the

use of

more

appro

priate

f lex ib i l i ty

representat ion.

10)

Same

as

present note

7).

11) Same as present note 10).

12)

Same

as

present note 11).

13)

For checking branch leg:

F o r

;: <

0 , 9 :

1.5 - - -

_

Rm)2/3 ~ ) l / 2 ~ )

Tr

m rp

i T ~ / T r ) 1.5

F o r ~ : ) = 1.0:

i =

0.9 ( ~ t

c;

Linear

interpolation is to be used for : : )be tween 0,9 and 1,0

For

checking run legs:

i

=

0.8

~ ~

2 1 3

;:);

2,1

minimum

Stress

ntensification Factors

9



NC-3653.3-NC-365H.l

SECrJON

III. DIVISIO: ' 1 -

SUBSECTION

NC

1986

Edition

M

•.

M •. .H, . •H,, =

r run

pipe mean cross-sect ional radius, in. ·

r ,., =branch mean cross-sectional radius, in.

U se

i T b / T r )

i n p l a c e

o f

i;

b u t

n o t

less t h a n

1.0.

z

n(C )2

'

i

3

m b , n .

,=effective

branch wall thickness,

=lesser of T or iT

Tb

nomina

ranch wall thickness, in.

,=nominal wall thickness of

run

pipe, in.

For

the ~ , use M •

Ms.

and

omit

l egs

Me

as

defined in NC-3633.3(a);

I

fllfa

Z

for

the run pipe

NC-3654

Consideration of

Level C Service

Limits

For Service Loadings for which Level C Service

Limits are

designated,

the conditions of

Eq. (9) shall

be met.

In calculating the

resultant

moment

loading

M

8

), the

effects

of anchor

displacement

due to

earthquake

or

other

secondary effects need not be

included.

The allowable stress

to

be use for this

condition is

2.25S

but

not greater than 1.8Sr

S = basic material yield strength at Design T em

perature, psi

Sit= basic material allowable stress at Design

Temperature,

psi

NC-3655

Consideration

of

Lenl

D Service

Limits

For

Service Loadings for

which

Level D Service

Limits are

designated,

the conditions of

Eq.

(9) shall

be met. In

calculating the

resultant

moment

loading

M ) ,

the effects of

anchor

displacement

due

to

earthquake or

other

secondary effects need not be

included. The allowable stress to be use for

this

condition is

3.0S

but

not

greater

than 2.0S,

S_,=basic

material yield

strength

at Design

Tem-

perature.

psi

Sit=

basic

material allowable stress at Design

Temperature, psi

NC-3658

Analysis of Flansed Joints

Flanged

joints

shall be

analyzed

for compliance

with one of the

fo11owing

subparagraphs.

NC-3658.1 Any Flanged Joint. Flanged joints may

be analyzed

and the

stresses evaluated by using

the

methods given in Appendix XI as

modified by (a)

166

4

WRC Bulletin

329



1986

Edition

o..t.<:

phon

W e l d i n < ; ~ elbow or

pi pe

bend [Notes (3)1

1), 2), 3), 4)]

ClOMiy apa<:..:l mi1er

bend [Notes

(1) ,

( 2) . ( 3) . (

4)

J

s

< r l

+ t a n 0)

hend [Notes 1), 2),

( 3). ( 4 . ( 5 l

s r ( l +tan 9)

Weldtng

11111

per

ANSI

8113.9 [Notn (1), 21)

F a b r i c a t e d branch

c onne c t i on r e in fo rced

wi t h pad o r

sa d d le

[N o t e s (1 ) , ( 2 ) , ( 6 )

7), 11)]

Unreinforce<l

fabricat..:l

IM

( N o t (1), (10))

Fle.•b•hty

C h a r a c ~ H I I t • c

t.R

r>

1t.

cot

2r

t. (1 +

cot

IJ)

2r

4 4

r.

---

r.

+ .,,

r l .

)''•

NC-3<XXl

-

DESIGN

Flex•b•l•ty

Factor;;

1.65

h

1.52

1.52

,

Note ( 9 )

Note (9)

Streu lnt< na•·

f•caflon Factor t

0.9

0.9

0.9

0.9

0.9

h t.

tlg. NC-3673.2(b)-l

Ske Ch

FIG. NC-3673.2(b)-l FLEXIBILITY

ND

STRESS INTENSIFICATION FACTORS (0

0

It . s 100)

171

Stress Intensification actors

Omit

41



@

@

42

O...c.rtphon

Fa b r i c a t e d

branch

con

n e c t io n

ot he r

than Fad

or sadd le r e i n fo rc e d

[Notes

7 ) , (8))

Girth

bun

w•ld

[Not•

(II]

r. l 0.237 ln.

Gonh

butt

wald

[Not•

(II)

t

< 0.237

In

t

' 'r ' efentlal ftUM w.Sded

w.ld..:l

101nta

N•·'

e (

12) )

ra . ..

to•nt

SECfiON 111. DIVISION I

SUBSECTION NC

F&e••btftty

Fa<1or t

Note

9 )

I

StrHI

lnt•natfic•hon

Fa<1or 1

Note

( 1 3 )

I 0

1.9

mal<.

r

o 9(1 + 36/r.l

but

not la11 than 1.0

2.ti(C,It .l

but

t\01

••• than 1.3

2.1

1986

E ~ i t l o n

Skelch

Fill NC·Je73.21bl·2

Ftg

NC-4427

1

lll<atchH lc·1),

(c-2).

and

(<:·3)

fig. NC-4611·1

r · ~ ~ r 1

I

3Ci

deg

taper..: tran•lfk>n

[Notes

(1),(2)]

~ a f l t r i e

enrl .eeantrie

r ed u ce r s [Notes

(1)

(2)

( 1 0 ) )

(ANSI B16.9)

Threadotd p i ~ joint

or threadotd l ~

t .l .. 0.0036

£, + u .

r

'·

2.0

mu. Of

0 ) '"

.5 + 0.01o ::::

•

2.3

Fia .

NC-4250-1

.f __

I f ~ *

.

o

Omit

FIG. NC-3673.2<b>-l FLEXIBILITY AND STRESS

INTENSIFICATION

FACTORS

(0

0

It . s lOO)(CONT O)

172

WRC Bullet in 3 9



1986 Edition

NC-3000 - - DESIGN

Fig:. NC-3{)73.2(b)-1

FIG. NC-3673.2(bl-l <CONT Dl *

NOTES:

( 1) The following nomenclature applies

r

=

mean radius

of p1pe.

in. {matching

pipe

for tees

and elbows)

t =

nommal wall thickness

of pipe. in. [matching

pipe for

tees

and

elbows. see

Note (9)]

R

= bend

radius

of elbow or pipe bend.

in.

8

=

one-half

angle

between adJacent

miter axes.

deg.

s = miter

spacing

at center l ine. in

r. =

reinforced

thickness.

in.

13

=average perm1ssible

mismatch at girth

butt

welds

as

shown in

Fig.

NC-4233-1. A value of 131ess than

Y in.

may

be used provided the smaller mismatch is specif ied for fabricat ion. For

f lush

welds.

as defined

in

Fig.

NB-

368

3. 1

cl-1, b

may

be

taken

as zero.

i =

1.0,

and flush

welds need not be ground.

D.

outside diameter.

in.

(2)

The

flex1bility factors

k and stress

intensif ication

factors apply to

bendmg 10

any plane for

fittings

and shall in no

case be

taken

less than unity.

Both

factors apply

over the

effect ive arc length

(shown

by heavy center l ines in the

sketches)

for curved

and miter elbows.

and

to

the

intersectiOn pomt

for

tees. The values of

k

and i

can

be read directly

by entering

with

the characteristic h

computed

from the equations given.

(3) Where f langes

are

attached to one or

both

ends. the values of k and i shall be corrected

by

the factor c given below.

which can be read d1rectly from

Fig.

NC-3673.2(bl-5. entering with

the

computed

h.

(a)

One end

f langed.

c

=

h '•

(b)

Both ends

f langed.

c =

h

'>

(4)

Also includes single

m1ter jomts

(5)

When

t 1

5r

_

h =

4

05 r J r

(6) The equat1on applies

only

if

the

fo l lowmg

cond1tions

are met

(a)

The

re1nforcement area requ1rements of NC-364 3

are met

(b)

The

ax1s of the branch pipe 1s normal to the

surface

of run p1pe waiL

(c)

For

branch

connections in

a p1pe. the

arc distance

measured

between

the

centers

of

adJaCent branches

along the

surface of the

run p1pe is

not less

than

three

t imes the

sum of

t h e ~ r mside radii in the

longitudinal direction

or

not

less

than

two

t imes the sum of the1r inside radii along the

circumference

of the run pipe.

(d) The ms1de corner radius r [F1g N C - 3 6 7 3 . 2 b ~ 2 ]

for

nominal branch pipe

size

greater than 4 m. shall be between

10%

and 50% T The

radius

r is not

required for

nominal branch pipe size smaller than

4

in.

(e)

The

outer rad1us r IS

not less than the larger of T.l2. (T - Y)/2 (Fig.

NC-3673-2(bl-2 sketch

(c)] or

T,/2.

(f)

The outer radtus r IS not less than the larger of

1)0002/ ldo

(2) 2

s1n

II)'

t1mes

the

offset for the

conf1gurat1ons

shown in F1g NC-3673

2(bl-2

sketches

(a)

and

(b).

(g)

R_ T,

·

50

and

r

_ R ~ ·; 0.5

(h)

The

outer rad1us r, IS not reqUired

prov1ded

an add1t1onal mult1pller of 2.0 IS mcluded in the equations for branch

end and run end stress intens1ficat1on

factors

In this case.

the

calculated value

of

i

for the

branch

or run shall not

be less than

2 1

(7)

The equat10n applies only

if

the follow1ng condit ions are met

(a)

Cone

angle n

does

not exceed

60 deg.

(b)

The

larger

of D, I

r,

and

D

I r,

does

not exceed 100

(c)

The

wall

th1ckness

is not

less

than r,

throughout the body of

the reducer.

except in and immed1ately

adJacent to

the

cylmdr1cal

port ion on the

small

end. where the

th1ckness

shall not be

less

than

t,.

(d) For eccentnc reducers. a is the maximum cone angle

(8) Factors

shown

apply to

bending;

flexibility

factor for torsion equals 0.9.

(9) The designer is

caut1oned

that cast

butt welding elbows may

have

considerably heav1er

walls

than that of

the

pipe

with wh1ch

they

are used.

Large errors may

be

introduced

unless

the

effect

of these greater thiCknesses is considered

( 1

0) The stress mtens1flcat10n factor i shall in no case be

taken as

less than

2 1

( 1 1)

C. the

f1llet weld

length. For

unequal

leg

lengths.

use the

smaller

leg length for C.

See

abe l Al for proposed changes .

Stress Intensification Factors

43



f la. NC-3673.2(b)-2

SECTION Ill. DIVISION l - SUBSECTION NC

enr l h r

- Branch

do

,.

m

T

b

P

Tb

(c)

(at

Ll

''J

,

Rm

;p

2

r b · r b • 0 6 6 7 v

o

45°

d • outttdtt

dtameter of

branch P•Pe.

tn

r ...

..

mean r1d1u1

of branch P•P<& m

do

,,

m

Br&nch

T

b

]

p

r,

Branch

GENERAL

NOTH

f f ~ < ~ t

1

Rm

(bl 2

(dl

1986 Edition

dd

r r ow

r·

'

nom.nal thtckneaa of brench p pea,

'

R_ • mean radtul

of run

ptpe.

'

( 2} If L ~ l t U t l s Of f )((f l'f" 'd" 0 s \ r

r

then r .. can be t.aken

th t '

' dnJ S 10 thf"'

t ...

ntttt

of T

T • nomtnal th•cknet-a

of

run P'f:M l'.

tn

FIG. NC-3673.2(bJ-2 BRANCH DIMENSIONS

174

WRC

Bulletin

3 9



250 Generalized Yield Surfaces for Plates and Shells, by D B. Peterson, W. C. Kroenke, W. F. Stokey, and W. J. O Donnell, July 1979.

251

Comparison

of Three-Dimensional

Finite

Element and

Photoelastlc

Results

lor

Lateral Connection,

WC-12B2,

August 1979.

252

Ultrasonic

Evaluation and Sectioning

of

PVRC

Plate

Weld

Specimen

201, by A. C. Adamonis and E.

T

Hughes, September 1979.

253 A

Survey

of Simplified

Inelastic

Analysis

Methods,

by K E Nickell, October 1979.

254

( 1) A

Critical Evaluation

of

Plastic Behavior

Data and a

Unified Deflnltlon of

Plastic Loads for Pressure

Components,

by

J.

C Gerden;

(2)

Interpretive Report

on Limit Analysis

and Plastic Behavior

of Piping Products by E. C. Rodabaugh; (3) Interpretive Report on

Limit

Analysis of

Flat Circular

Plates, by W. J.

O'

Donnell,

November

1979.

255

Experimental

Investigation of

Commercially

Fabricated 2:1

Ellipsoidal

Heads Subjected to Internal Pressure, December 1979.

256

Review of

Data Relevant

to the

Design

of

Tubular

Joints

tor

use

In

Fixed

Offshore Platforms, by

E

C. Rodabaugh, January 1980.

257

Analysis of the

Ultrasonic

Examinations of PVRC Weld

Specimens

155,

202 and

203 by Standard and

Two-Point

Coincidence Methods, by

R

A. Buchanan

and 0. F. Hedden, February 1980.

258 International Benchmark Project on Simplified Methods for Elevated Temperature Design and Analysis: Problem 1-The

Oak

Ridge Pipe Ratchetlng

Experiment; Problem

l i The Saclay Fluctuating

Sodium

level

Experiment,

by H. Kraus, May 1980.

259 Analysis

of

the Radiographic Evaluation of PVRC Weld Specimens 155, 202, 203, and 251J, by

E

H. Ruesche r and

H

C. Graber, June 1980.

260

Energy Dissipation

Characteristicsof

Pipes

and

Short

Compression Members

as

Elements of Pipe-Whip

Restraint,

by

S.

S. Palusamy, R

L

Cloud, and

T.

E.

Campbell, August 1980.

261

Effects

of Porosity on

the Fracture

Toughness

of

5083,5456, and 6061 Aluminum Alloy Weldments, by W. A. McCarthy,

Jr.

H. Lamba and F. V. Lawrence,

Jr.

September 1980.

262 ( 1}

Derivation of

ASME Code

Formulas for the

Design

of Reverse

Flanges, by E. 0. Waters and

R.

W. Schneider. (2) Functional Test of a Vessel with Com-

pact Flanges In

Metal-to-Metal Contact,

by J.

Webjornand

R. W. Schneider,

(3) Interpretive

Report on

Gasket

leakage Testing, by H. Kraus, October 1980.

263 An Annotated

Bibliography

on

the

Significance, Origin and

Nature

of Discontinuities In Welds, 1975-1980, by C. D Lundin and S.

J.

Pawel, November 1980.

264 The Influence

of Mulllaxlal Stress on

low-Cycle

Fatigue

of

Cr-Mo-V

Steel

at

1000 °F,

by

fl.

H.

Marloff

and R. L Johnson, December 1980.

265

Interpretive

Report on Small-Scale

Test

Correlations

with

Oata,

by

R

Roberts and

C.

Newlon, February 1981.

266 Weldability and Fracture Toughness of 5 Nl Steel-'Part

1:

Weld Slmulatloo Testing, by A. Ohooge,

K

Ostyn, W. Provost and A. Vinckler, Welda-

bility

and

Fracture Toughness of 5

Nl

Steei-'Part 2:

Wide

Plate Testing, by A. Dhooge, W. Provostarrd A. Vinckier, Aprll1981.

267 Elastic-Plastic

Buckling

of internally Pressurized

Ellipsoidal

Pressure

Vessel Heads, by D. Bushnell,

May

1981.

268

Review of Worldwide Weld Discontinuity Acceptance

Standards, by C. D. Lundin, June 1981.

269 Interpretive Report on Dynamic Analysts of Pressure

Components-Second

Edlllon, August 1981.

270

Long-Range Plan

for Pressure-Vessel

Research-Sixth

Edition

by

the

Pressure Vessel Researdl

Committee,

September 1981.

271 ( 1} Methods

of Analysis of Bolted Flanged

Con-ct ions-A Review,

by

A. E

Blach

and A. Bazergui (2)

Gasket leakage

Behavior Trends, by H D. Raut, A.

Bazergui andL Marchand, October 1981.

272 ( 1

Design

of Beam

Columns

with ateral-Torsional End Restraints, by

T. L

Hsu and G.

C.lee

(2) Tapered

Columns

withUnequal Flanges, by G.

c.

Lee and T.

L

Hsu,tlovember 1981.

273 Design

Implications

of Recent Advances In ElevatedTemperature Bounding Techniques, by J. S. Porowski, W.

J.

O Donnell and M. Badlani, December 1981.

274

International

Benchmark Project on Simplified

Methods

for Elevated Temperature Design and Analysts: Problem The

Sactay

Fluctuating Sodium

level

Experiment;

Comparison of Analytlcill

and Experimental

Results; Problem

lii_.:.The

Oak Ridge

Nozzleto

Sphere

Attachment,

by

H. Kraus, January 1982.

275

The Use

of

Quenched and Tempered

214

Cr-1

Mo

Steel

for Thick

Wall

ReactorVesselsln

Petroleum

Refinery

Processes: An

Interpretive

Review

of

25

Years

of Researdl and

Application,

by W. E.

Erwin

and J.

G.

Kerr, February 1982.

276

A Summary

and Critical Evaluation of

Stress ntensity Factor

SolutlonsDfComer Cracks

at

the Edge Dl

a

Hole, by

R L Cloud and S. S. Palusamy,

April

1982.

277 High Temperature Properties of

214

Cr-1

Mo

Weld

Metal, by

C. D

Lundin,

B. J.

Kruse and M.

R.

Pendley,

May

19S2.

278 The Crack Arrest

Properties

of 9 Nickel Steels for

Cryogenic

Applications, byRD. Stout and A. W. Pense, June 1982.

279

Weldablllty and Fracture TDughness of

Quenched

and

Tempered

9 Nickel

Steel: Part

1-Weld

Simulation

Testing;

Part 11-Wlde

Plate Testing by

A.

Dhooge, W. Provost

and A. Vinckier, July

1982.

280 The Varestralnt Test, by C. D Lundin,

A.

C.

Lingenfelter, G.

E.

Gmtke,

G

G. Lessmarln and S. J. Matthews, August 1982.

:281 Hydrodynamic Response

of

f luid

Coupled Cylinders:

Simplified

Damping and Inertia

Systems, by S. J. Brown, October 1982.

282 Elastic-Plastic Buckling

of

Axially

Compressed

Ring

Stiffened

Cyllnders•Test vs. Theory, by D Bushnell,

November

1982.

283

A Critical Evaluation Df Fatigue Crack Growth Measurement Techniques for Elevated Temperature Applications, by

A E.

.Carden, February 1983.

284

The

External

Pressure Collapse Tests of Tubes, by

E

Tschoepe and J.

R.

Maison, 1983.

285

( 1 Stress ndices and Flexibility Factors

for

Concentric

Reducers, by

E

C.

Rodabaugh and

S.

E

Moore

(2) Finite

Element

Analysis of

Eccentric Reducers

and Comparisons with Concentric Reducers

by

R R Avent, M.

H:

Saddand E.

C

Rodabaugh, July 1983.

286

fatigue

e h a ~ i o r of

Aluminum

Alloy

Weldments,

by W. W. Sanders, Jr. and

R H.

Day, August 1983.

287

Welding

of

Copper and

Copper Base Alloys,

by R

J.

C.

Dawson, September 1963.

288

Fracture

DfPlpellnes and

Cylbuiers Containing

a

Circumferential

Crack, by F. :Erdogan and H. Ezzat

October

1983.

289

Hot

Cracking.Susceptlblllty

of Austenitic

Stainless

Steel Weld Metals, by C. D Lundin and

C.

P

D Chou, November 1983.

290 Factors

Affecting Porosity

In Aluminum Welds-A Revlew;by J. H. Devletlan and W. :E Wood, December 1983.

291

Fracture

Control

of Pressure Vessels U p

to 216

Inches Thick,

by P.

0.

Metz, January 1984.

292 PVRC Milestone Gasket Tests-First Results, by A. Bazergui and

L

Marchand, February 1984.

293 Current Welding

Research

Problems, Compiled and Edited by R. A. Kelsey, G. W. Oyler and C. R. Felmley, Jr., April 1984.

294 ( 1) Creep of Bolted

Flanged

Connections, by H Kraus and W. Rosenkrans (2) Short

Term

Creep and

Relaxation

Elehavlor

of

Gaskets, by A. Bazergui, May

1984.

Listing continued on outside back cover



295 Fundamentals of Weld Discontinuiti es and Their Significance, by C. D. Lundin, June 1984.

296 Fitness-for-Service

Criteria for

Pipeline Girth-Weld Quality, by R P. Reed,

M. B

Kasen,

H.

I, McHenry, C. M. Fortunko. and

D.

T.

Read,

July 1984.

297 local Stresses In Cylindrical Shells Due to External loadings on Nozzles-Supplement to WRC Bulletin No. 107, by J. L Mershon, K Mokhtarian, G. V. Ran-

jan, and E. C. Rodabaugh, August 1984.

298 long-Range Plan

lor

Pressure-Vessel

Research-Seventh

Edition, by the Pressure Vessel Research Committee, September 1984.

299

1) Engineering Aspects of CTOD

Fracture

Toughness Testing, by G.

W.

Wellman and

S.

T. Rolfe; 2) Three Dimensional Elastlc·Plastlc Fi nite Element

Analysis of Three-Point Bend Specimen, G. W. Wellman. S. T. Rolfe and R. H. Dodds; and

3)

Failure Prediction of Notched Pressure Vessels Using the

CTOD Approach, by

G.

W. Wellman, S.

T.

Rolfe and R. H. Dodds, November 1984.

300

(

1)

Technical Position

on

Criteria

Establishment;

2)

Technical Position on Damping Values for Piping-Interim Summa ry Report;

3)

Technical Position on

Response Spectra Broadening;

4)

Technical Position on Industry Practl<:4, December 1984.

301 A

Parametric

Three-Dimensional

Finite Element

Study of

45

Degree

Lateral

Connections, by P. P. Raju, January 1985.

302

1)

Postweld HeatTreatment

of Pressure Vessels, by

R. D

Stout; 2) Relaxation Stresses In Pressure Vessels, by P. S. Chen, W. A. Herman, and A. W. Pense;

3) A Study of Residual Stress In Pressure Vessel Steels, by R J. Zhou, A. W. Pense, M. L Basehore. and D

H.

Lyons, February 1985.

303

Interpretive

Report on

Dynamic

Analysis of Pressure Components-Third Edition-April 1985.

304 Experimental Limit Couples for Branch Moment loads on 4-ln. ANSI B16.9

Tees

by J Schroeder, May 1985.

305

Summary Reports Prepared by the JPVRC Subcommit tee

on

Hydrogen Embrlttlement: 1) Hydrogen Attack Limit of 2'/. Cr-1 Mo Steel by Task Group I; 2)

Embrittlement of Pressure Vessel Steels in High Temperature, High Pressure Hydrogen Environment by Task Group II;

3)

Hydrogen Embrlttleme nt of

Bond

Structure

Between Stainless Steel Overlay and

Base

Metal by Task Group Ill, June 1985

306

PVRC Flanged Joint User Experience Survey by J.

R

Payne, July 1985

307 Fatigue and Creep Rupture

Damage

of Perforated Plates Subjected

toCyllc

Plastic Straining In Creep Regime, by M.L Badlanl, T. Tanaka, J S. Porowskl and

W. J. O'Donnell, August 1985

308 Verification and Application of an Inelastic Analysis Method for lMFBR Piping Systems, by H. D. Hibbitt and E. K Teung, September 1985

309

Development

of

a Production Test Procedure

for

Gaskets,

by

A. Bazergui,

L

Marchand, and

H.

D. Raut, November 1985

310 Damage Studie s in Pressure Vessel Components, by

F

A. Leckie, December 1985

311 Assessment of the Slgnlflcance of

Weld

Dlscontlnutles: Effects of Microstruc ture and Discontinuities upon Fracture Morphology, by

C.

0. Lundin and C.

R.

Patriarca, January 1986.

312

Joining of Molybdenum Base

Metals

and Factors Which Influence Ductility,

by

A. J. Bryhan, February 1986

313

Computer

Programs

for

Sensitivity Analysis of Stiffened Cylindrical Shells, y R L Clterley, April 1986.

314

Bolted

Flanged Connections

with Full

Face Gaskets, by A. E. Blach,

A.

Bazergul, and R. Baldur, May 1986.

315 Stress Rupture Behavior of Postweld Heat Treated 2-'\'

4

Cr-1Mo Steel Weld Metal, by C. D. Lundin, S.C. Kelley, R. Menon, and B. J Kruse, June 1986

316

1)

Technical

Position

on

Piping

System

nstallation Tolerances,

byE.

B. Branch, N. Kalyanam, D. E Landers, E

0.

Swain, andD A. VanDuyne;

2)

Technical

Posttlon

on

Damping Values tor Insulated Pipe-Summary Report, by J 1 Bitner, S. N. Hou, W. J. Kagay, and J. A. O'Brien, July 1986.

317 PVRC Ce ntrifugal Pump..Piplng Interaction Experlen<:4Survey, by J.

R

Payne, August 1986.

318 ( 1) Factors Influencing

the

.Measurement

of

Ferrite Content In .AustenltlcStalnless.Steel Weld Metal using Magneti c Instruments, by E. W. Pickering,

E

S

Robitz, and D. M. Vancter:griff;(2) Measurement

of

FerriteContentln.Austenlllc Stainless Steel Weld

Metal

Giving Internationally Reproducible Results, by

E

Stalmasek, September 19 86.

319 .Sensltlzation·1lf Austenitic Stainless

Steels;

Effect1>f Welding Variables on

HAZ

Senslllzatlon of AlSI304

and

HAZ Behaviorof BWR Alternative

Alloys 316

NG and 347,

by

C. D. Luctin,

C.

H.

Lee,

A.

Menon, and

E

E. Stansbury, November 1986.

320 Welding Metallurgy and

Weldabllity

of High Stren.Qth Aluminum A lloys , by S. Kou December 1986.

321 The Dynamic Deformation of Plplng, by J L. Mclean,P K. Beazley and A. H. Manhardt, January 1987.

322

1) The Strain

Aging Behavior of

Microalloyed

Steels,by W.

A.

Herman, M.A.Erazo, L R Depatto, M. Sekizawaand A.W. Pense; 2) The

Fracture

Toughness

Behavior

of

ASTM A737 Grade

Band

Grade CMicroalloyed PresSure Vesse l Steels, by J. A. Aadland, J.

l.

Qureshi and A. W. Pense;

3)

The Fracture Be

havior of ASTM

A737

Grade Band Grade CMicroalloyed Steel Weldments, by J M. Aurrecoechea,

B.

Oain and A. W.Pense; {4) Long

Time

Stress Relief

Effects In ASTM A737 Grade Band Grade CMicroalloyedSteels, b yN. Shinohe, M.

SeklzawaandA.

W. Pense,

April1987.

323

Monograph on

Narrow-Gap

Welding

Technology, by V, Malin, May 1987.

324

Investigation

of

Design

Crlleria for Dynamic Loads

on

Nuclear Power

Piping,

by

R. J. Scavuzzo and P.

C.

Lam, June 1987

325 Further Gasket

Leakage

Behavior

Trends, by A. Bazergui, L Marchand andH

0.

Raut, July 1987.

326

Revised Bulletin 191-August 1987. Suggested Arc-Welding Procedures for Steels Meeting Standard Specifications, by C.

W.

Ott and D. J. Snyder. This

Revision is a part onne WAC book, Weldability

of

Steels-Fourth Edition.

Revised

Bulletin 297. Local Stre.ss'es

ln

Cylindrical ShellsDue

to

ExternalLoadings on Nozzles-Supplement

to

WRC Bullet in 107 (Revision

1 , by

J L. Mershon, K

Mol<htarian, G. V. Ranjonand E. C. Rodabaugh, September 1987.

327

Long,Range Plan for Pressure-Vessel Research-Eighth Edition, by the Pressure Vessel Research Committee , October 1987.

328

1)

SpeCimen ThicknessEffects for l a s t i c P i a s t i ~ C T O D Toughness ofanA36 Steel, by G. W. Wellman,

W.

A. Sorem,

R

H. Dodds, Jr., and S. T. Rol fe; 2) An

Analytical and Experimental Comparison

of

Rectangular and Square CTOD Fracture Specime ns of an A36 Steel,

byW.

A. Sorem, R H. Dodds, Jr., and S.

T. Rolfe, November 1987.

329

Accuracy of Stress Intensification

Factors

for Branch Connections, by E. C. Rodabaugh,

December

1987.

Copyright© 1987 Welding Research Council

Requests for reproduction or republi cation permission should be addressed to the

President and Executive Director, Welding Research Council.

Documents

Wrc 329-1987 Accuracy of Stress Intensification Factors for Branch Connections_part4