modification thickness of a flange

8/11/2019 Modification Thickness of a Flange

1/3

Flange Calculation sheetDoc No Sheet

1/3Bolted flange connections to ASME VIII, div. 2 Appendix 2

Design Basis

Design Code:

ASME Boiler & Pressure Vessel Code - section VIII, Division 1, Appendix 2

Units of calculation

Input Data

Variable Notes

Flange and Flange facing

Pipe Data Nominal Pipe Size

Pipe Schedule

Flange Pressure Rating

Pipe OD (actual)

Pipe wall thickness (Uncorroded)

Length Through Hub

Flange thickness

Bolt circle diameter

Hub Diameter (Largest)

Flange outside diameter

Bolts Bolt Standard

Bolt Size (Specify M-Type , ISO)=

Number of Bolts=

Bolt stress area (per bolt)

Gasket Gasket Type

Gasket diameter , MEAN(RTJ)/OD(RF):

Gasket contact width w(RTJ) or N(RF)

Min. design seating stress

Gasket factor

Design Design Pressure

Conditions Design Temperature

Corrosion Allowance

External Axial Force (strain)

Loads Moment

Moment

Moment

Orientation of flange

Stresses Material

At d esign temperature

At amb ient

Material

At d esign temperature

At amb ient

E Modulus

Conclusion

Flange design is acceptable for listed design pressure 52.6

Bolting design is acceptable for design pressure

Max. operating pressure before failure of flange or bolting is 477.4 psi

Bolting design is acceptable for gasket seating condition

% close of Max.

Oper. Pressure

36" Flange

Max. value

could be

modified(-15.9 mm

from original

88.9mm )

0.0 N/mm

ASME B 31.3

ASME B 31.3

Sa

Sb

Flange

Flange

Sf_oper

Sf_atm

P

ca

Faxial

w or N

y

m

Bolting

Mx

My

Mz

x,y,z

dbolt

nbolt

Abolt

tmax

PCD

X

A

ODpipe

tn

h

t

NPD

Source of data Input

ASME B 31.3

ASME V III, table 2 -4- Pag 380

ASME V III, table 2 -5.1-Pag 381

ASME V III, table 2 -5.1-Pag 381

ASME B 16.5

ASME B 31.3

ASME B 1.1

ASME B 36.10 (Table 1)

ASME B 36.10 (Table 1)

ASME B 16.5 Modified

ASME B 16.5

ASME B 16.5

ASME B 16.5

137.9 N/mm

y

485.0 N/mm

485.0 N/mm

137.9 N/mm

A320 L7 d-


2/3

Flange Calculation sheetDoc No Sheet


Calculations

Gasket key dimensions

Gasket outside diameter 977.9 mm

Basic gasket seating width b0 = N/2 or w / 8 (RF or RTJ) Table 2-5-2 16.0 mm

Effective gasket seating width b=b0for b0 < 1/4"

or b = 0.5(or 2.52 for metric) * (b0)0.5

for b0 > 1/4" Table 2-5-2 10.1 mm

Gasket load reaction diameter G = mean gasket diameter for b0 < 1/4"

or G = Gasket OD - 2*b for b0 > 1/4" 957.7 mm

Flange values

Thickness of hub at small end g0= tn - ca = 8.0 mm

Thickness of hub at back of flange g1= (X-B)/2 = 8.2 mm

Radial dist. from PCD to large hub diam. R = (PCD-X)/2 = 85.7 mm

Inside diameter of flange B (Corroded ID) = ODpipe- 2 * g0= 898.0 mm

Equivalent Working Pressure using Kellogs Method

Resulting Bending Moment Mres = SQRT(Mx^2+Mz^2) 0 Nmm

Equivalent Pressure Peq = 16 * Mres / ( * G3

) + 4 * Faxial / ( * G2

) 0.00 N/mm

Calculation Design Pressure Pd = P + Peq 1.72 N/mm

Load and Bolt Calculations

Total join t-con tact su rface com pression load Hp= 2 * b * * G * m * P d = 261,436 N

Total hydrostatic end force H = / 4 * G2

* P d= 1,242,002 N

Min. required bolting load for operating conditions Wm1= Hp+H = 1,503,438 N

Min. required bolting load for gasket seating Wm2= * b * G * y = 2,091,184 N

Total required cross-sectional area of bolts Am= greater of W m1/Sbor W m2/Sa= 15,164 mm

Total availab le cross-section al area of b olt s Abolts = 34,684 mm

Flange design bolt load W = 0.5 * ( Am + Abolts ) * Sa = 3,437,040 N

Required bolt rootdiameter= = ( 4 * Am / ( nbolt* ) )0.5

24.6 mm

Flange Moment Calculations

Flange Loads Lever arm Flange Moments

Operating Conditions

HD= / 4 * B2

* P d= 1,091,844 N h D= R + 0.5 * g 1= 89.8 mm MD= HD* hD = 98,053,023 Nmm

HG = Hp = 261,436 N h G= 0.5 * ( PCD - G) = 64.0 mm MG= HG* hG = 16,739,743 Nmm

HT= H - HD= 150,159 N hT = 0.5 * ( R+g 1+hG) = 79.0 mm MT= HT* hT = 11,858,024 Nmm

M0 oper= MD + MG+ MT= 126,650,790 Nmm

Seating Conditions

HG = W = 3,437,040 N hG= 64.0 mm M0 atm= 220,073,687 Nmm

Bolt Spacing= = PCD * SIN( / nbolt) 106.4 mm

Bolt pitch correction factor CF = [bolt_spacing / (2 * d bolt+ 6 * t / ( m + 0.5))]0.5

(or minimum 1.0) 1.00

Flange Factors fr om fi g. 2-7.1 Flange fact or s i nvo lving H/ H_0 o r g 1/ g0 S tr ess formul a f actors

K =A / B 1.303 h0 = (B * go)0,5 84.8 mm = t * e +1 1.774

T 1.796 h / h0 1.839 =4

/ 3 * e * t+1 2.032

U 8.225 g1 / g0 1.025 = / T 0.988

Y 7.484 F 0.899 = t3 / d 4.497

Z 3.867 V 0.517 = + 5.480

f 1.000 m0 =CF * M 0 oper/ B 141,040 N

e = F / ho 0.0106 mm- mG =CF*M0 atm/ B 245,076 N

Poisson's Ratio Assumed = 0.3 d = U / V * h0 * g 02

86,511 mm

36" Flange

Page 2 of 3


3/3

Flange Calculation sheetDoc No

36" Flange

Sheet


Calculations

SUMMARY OF STRESSES:

Calculated Allowable Accept

Operating

Longitudinal Hub Stress: SH=f * m0 / (* g12

) = 382 N/mm 1.5 * Sf oper= 728 N/mm OK

R adial Flange S tr es s: SR = * m0 / (* t2

) = 10 N/mm Sf oper= 485 N/mm OK

Tangential Flange Stress: ST= m0* Y / ( t2

) - Z * SR= 160 N/mm Sf oper= 485 N/mm OK

C om bined S tr ess : great er of (SH+SR) / 2 or (SH+ST) / 2 = 271 N/mm Sf oper= 485 N/mm OK

Bolt Stress Wm1 / A bolts 43 N/mm Sb 138 N/mm OK

Seating

Longitudinal Hub Stress: SH = f * mG/ ( *g12

) = 663 N/mm 1.5 * Sf atm= 728 N/mm OK

R adial Flange S tr es s: SR= * mG/ ( * t2

) = 17 N/mm Sf atm= 485 N/mm OK

Tangential Flange Stress: ST= mG* Y / ( t2

) - Z * SR= 278 N/mm Sf atm= 485 N/mm OK

C om bined S tr ess : great er of (SH+SR) / 2 or (SH+ST) / 2 = 471 N/mm Sf atm= 485 N/mm OK

Bolt Stress Wm2 / A bolts 60 N/mm Sa 138 N/mm OK

REVERSE CALCULATION - max operating pressure

m0values due to allowable stresses:

Longitudinal Hub Stress: m01 = * g12

* 1.5 * Sf oper/ f = 268,720 N

Radial Flange Stress: m02 = * t2

* S f oper/ = 6,971,100 N

Tangential Flange Stress: m03 = * t2

* S f oper/ ( * Y- * Z ) = 427,154 N

Combined Stress: largest of m04 = 2 * Sf oper/ ( f / ( * g12

) + Y / t2+ / ( * t

2) ) = 231,985 N

m04 = 2 * Sf oper/ ( f / ( * g12) + / ( * t

2) ) = 349,316 N

Select min. m01to m04 m0 = 268,720 N

Max flange moment M0 = = m 0* B / CF = 241,305,119 Nmm

Max operating pressure P=

= 8 * M0 / [ * (B2 * ( PCD - (X + B) / 2) + 8 * b * G * m * (PCD - G) + (G 2 - B2) * (PCD - (G + B)/ 2))] = 3.3 N/mm

Bolting P= = Abolts* Sb/ ( * ( 2 * b * m * G + 0.25 * G2

) ) = 5.5 N/mm

BLIND FLANGE THICKNESS CALCULATION: (3.5.5)

Minimum thickness of flange

(Operating - W=Wm1) eoper= ( 0.3 * G2

* P / ( S f oper) + 1.909 * W m1* hG/ ( S f oper* G ) )0.5

+ ca 38.6 mm

Minimum thickness of flange

(Seating - P=0) eoper= ( 0.3 * G2

* P / ( S f oper) + 1.909 * W * hG/ ( S f oper* G ) )0.5

+ ca 31.6 mm

Max pressure for actual thickness

Operating pmax= (e - ca )2

* S f oper/ ( 0.3 * G2+ 1.909 * * hG* (2 * b * m + 0.25 * G )) 6.4 N/mm

Flange Rigidity Check (According to Appendix S)

Rigidity index J = 52.14 * M0 oper* V / ( * Emod * G 02

* h 0* 0.3) = #DIV/0! #DIV/0!

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modification thickness of a flange

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