Rectangular Flange Design
Please note that the abreviations with suffix S are used to denote short side while those with suffix L are used to denote
long side
Design Calculation has been carried out based on PD 5500 Enquiry Case 5500 / 133 with ASME stress values
Design Pressure
Pd
=
5 N/mm2
Outside Length of long side
Al
=
2620 mm
Outside Length of short side
As
=
775 mm
Inside Length of long side
Bl
=
2373.5 mm
Inside Length of short side
Bs
=
528.5 mm
End Bolt center to center long side
Cl
=
2520 mm
End Bolt center to center short side
Cs
=
675 mm
Gasket O.D. long side
Gol
=
2440 mm
Gasket I.D. long side
Gil
=
2370 mm
Gasket O.D. short side
Gos
=
600 mm
Gasket I.D. short side
Gis
=
530 mm
No. of bolts
n
=
62
Gasket material
=
IJA
Gasket factor
m
=
3.75
Design seating stress
y
=
52 N/mm2
Width of gasket ( same on both sides.)
N
=
Go-Gi/2
=
35 mm
Material of flange
=
SA-516 70
Yield stress at ambient temperature
Sfy
=
260 N/mm2
Allowable stress at design temperature
Sfd
=
136 N/mm2
Allowable stress at ambient temperature
Sfa
=
138 N/mm2
Youngs Modulus for flange @ Design
Ef
=
185000 N/mm2
Material of bolt / studs
=
SA-193 Gr. B7
Bolt size
=
M42
diameter
=
42
Root Area per bolt / stud
=
1018.218 mm2
Yield stress at ambient temperature
Sby
=
695 N/mm2
Allowable stress at design temperature
Sbd
=
172 N/mm2
Allowable stress at ambient temperature
Sba
=
172 N/mm2
When b < 6 mm ; b = bo else b = 2.5 x root (bo)
=
Effective width of gasket
bo
=
N/2 mm
=
17.5 mm
Effective width of gasket
b
=
10.46 mm
Gasket reaction long side
Gl
=
Gol-2b
2419.08 mm
Gasket reaction short side
Gs
=
Gos-2b
=
579.08 mm
Hydrostatic End Force
H
=
Pd x Gl x Gs
=
7004204.23 N
Compression Load on gasket
HG
=
2b x (2Gl + 2Gs) x m x Pd
=
2352056.52 N
Hydrostatic End force applied via shell
HD
=
Pd x Bl x Bs
=
6271973.75 N
Hydrostatic End force due to pressure
HT
=
=
Min. required Bolting Loads
Min. Bolt Load for Operating Condition
Wm1
Min. Bolt Load for Gasket Seating Condition
Wm2
=
=
=
=
=
=
=
=
=
=
=
=
=
=
Design Flange Load
W
Bolt Area for operating condition
Am1
Bolt Area for gasket seating condition
Am2
Min. Design Bolt Area requirement
Am
Actual Bolt Area
Ab
H-HD
732230.48 N
HG+H
9356260.75
2 x (Gl + Gs) x bx y
3261518.374
max(Wm1,Wm2)
9356260.75
Wm1/Sbd
54396.86
Wm2/Sba
18962.32
max.(Am1,Am2)
54396.86
Root area x n
63129.516
N
N
N
mm2
mm2
mm2
mm2
The no. of bolts selected is safe
Moment Arms
Radial distance from Bolt circle to I.D.
hD
Radial distance from Bolt circle to G.I.D.
hG
Radial distance from Bolt circle to circle at which
HT acts
hT
Max. Operating moment
Mop
Maximum Gasket Seating Moment
Matm
Flange thickness calculation check
Operating Condition
to
=
=
=
=
=
=
=
=
=
=
=
=
Gasket Seating Condition
tb
Cl-Bl/2
73.25 mm
Cl-Gl/2
50.46 mm
(2 x Cl x -Bl - Gl)/4
61.855 mm
HD x hd + HG x hG + HT x hT
623398965.5 N-mm
WxhG
472116917.4 N-mm
(6 x Mo)/(Sfd x (2 x (Cl+Cs))-n x
d1)^0.5
85.23 mm
=
(6 x Matm)/(Sfa x (2 x (Cl+Cs))-n x
d1)^0.5
73.63 mm
=
Min. required thickness
tmon
=
=
max(to,tb)
85.23 mm
Selecting flange thickness (excluding R.F.)
tact.
=
125 mm
Pbmax.
=
Max permissible spacing
=
6t x(E/2x10^5)^0.5 + 2Db / (m+0.5)
189 mm
Dimesnion Check for flange design
Dimesnion Check for flange design
=
=
The dimesions are acceptable
=
=
The dimesions are acceptable
(Al-Bl ) - (As-Bs ) = 0
0
(Cl-Bl ) - (Cs-Bs ) = 0
0
Additional check
Ratio of short to long side
Value taken from PD 5500
Min. thickness of welded or bolted flat
Min. spacing of bolts / studs
Min. thickness of welded or bolted flat with
narrow gasket ( at gasket face)
Main thickness e1
C
As/Al
Z
t1
Pb
=
=
=
=
=
=
t2
=
e1
e2
Min. thickness of welded or bolted flat with
narrow gasket ( at center)
t2
=
=
=
=
=
0.41
0.296
1.63
C x Z x a x (Pd / Sfd)^0.5
99.31
100.8
((0.3 x Gs^2 x Pd x Z^2)/Sfa)+((6 x
Wm1 x hG)/(n x Pb x Sfo))^0.5
114.71
(6xW x hG/n x Pb x Sfa)^0.5
57.31
(6xWm1 x hG/n x Pb x Sfo)^0.5
57.73
=
max(e1,e2)
=
mm
mm
mm
mm
mm
57.73 mm