in the "FLANGE LEAKAGE/STRESS CALCULATIONS"
where was the "Approximate Torque required to induce the above initial stress" coming from? it was refere to which code or standard? or refer to which paper or book?
thanks for the comment

the above question was related to CAESAR II "Flange leakage/stess calcuation model "
now I have another question:
it seem that the "Effective gasket seating width, b" calcuation not correct, due to it 2 time of the gasket width ,see following example:

FLANGE LEAKAGE/STRESS CALCULATIONS
Flange Inside Diameter [B] (User to verify) ......(mm.) 49.300
Flange Thickness [t]..............................(mm.) 25.500
Flange Rating (Optional) .............................. 600.000

Bolt Circle Diameter .............................(mm.) 127.000
Number of Bolts ....................................... 8.000
Bolt Diameter ....................................(mm.) 16.000
Bolt Initial Tightening Stress ............( KPa )


Uncompressed Gasket Thickness ....................(mm.) 17.460
Grade of Attached B16_5 ANSI Flange.................... 2.100
Leak Pressure Ratio [m] ............................... 6.500
Effective Gasket Modulus ..................( KPa ) 118000000.000

Externally Applied Moment ..... (optional) ....( N.m. ) 000
Externally Applied Force ...... (optional) .......( N.) 000
Pressure [P]...............................( KPa ) 6200.000

Disable Stress Calculations (Y/N) ..................... N


Flange Type (1-8, see ?-Help or Alt-P to plot) ........ 1.000

Flange Outside Diameter [A].......................(mm.) 165.000
Design Temperature ................................ C 30.000

Small End Hub Thickness [g0]......................(mm.) 5.500
Large End Hub Thickness [g1]......................(mm.) 17.350
Hub Length [h]....................................(mm.) 39.580

Flange Allowable @Design Temperature ......( KPa ) 137895.141
Flange Allowable @Ambient Temperature .....( KPa ) 137895.141
Flange Modulus of Elasticity @Design ......( KPa ) 195000000.000
Flange Modulus of Elasticity @Ambient .....( KPa ) 195000000.000
Bolt Allowable @Design Temperature ......( KPa ) 137895.141
Bolt Allowable @Ambient Temperature .....( KPa ) 137895.141
Gasket Seating Stress [y] .................( KPa ) 179264.000

Flange Allowable Stress Multiplier .................... 1.000
Bolt Allowable Stress Multiplier (VIII Div 2 4-141) ... 1.000

Disable Leakage Calculations (Y/N) .................... N
Disable ANSI B16.5 Checks (Y/N) ....................... N
Flange Face OD or Lapjt Cnt OD....................(mm.) 108.000
Flange Face ID or Lapjt Cnt ID....................(mm.) 49.300
Gasket Outer Diameter ............................(mm.) 88.105
Gasket Inner Diameter ............................(mm.) 76.995
Nubbin Width .....................................(mm.) 11.110
Facing Sketch ......................................... 6.000
Facing Column ......................................... 1.000


Flange Type: (Integral Weld Neck)

Effective gasket width parameters:
Effective gasket seating width, b......(mm.) 1.3887
Diameter of gasket load reaction, G....(mm.) 82.5500

thanks for comment and advice

no comemnt and feed back,why?