Subject
Flanges are structural and leakproof joints between pipes and/or nozzles that must also be able to support external loading without resulting in leakage or structural damage.
The principal flange types used in the chemical and related industries are Lapped, Socket, SlipOn and Welding Neck types specified by API, ANSI, BS and MSS
The principal design code for the establishment of pipeline and piping flange stresses is ASME VIII, Division 1, Appendices 2, P and S, which forms the basis for the calculations in the flanges calculator.
The flange calculator includes a database of 600; API, ANSI, BS and MSS standard pipeline and piping flanges ranging from ½ inch to 48 inch and an independent calculation facility according to ASME VIII.
In addition to the standard flange types and designs, Flanges also allows you to modify the standard (database) dimensions in order to calculate the strength and performance characteristics of nonstandard flange designs and swivel rings.
The output data is listed and designated according to the ASME design code, to help you verify the calculation results more easily.
For help using this calculator see Technical Help
Flanges Calculator  Options
Flanges includes Lapped, Socket, SlipOn and Welding Neck flanges in its database of 600 design and sizes. The calculator also automatically provides the tangential stress in a Swivel Ring for each design and size.
You enter: 
and the flange calculator will provide: 


A: outside diameter of flange

Aᵇ: total crosssection area of all bolts at root diameter

Aᵐ: minimum required bolt area; i.e. greater of Aᵐ¹ and Aᵐ²

Aᵐ¹: total crosssection area of all bolts at root diameter required for operational conditions

Aᵐ²: total crosssection area of all bolts at root diameter required for gasket seating

B: inside diameter of flange (bore)

B¹: radial dimension (B+g¹)

b: effective gasket seating (contact) width

b₀: basic gasket seating width

C: pitch circle diameter of bolts (studs)

c: the lesser value of tn and tₓ

d: factor

e: factor

F: factor

ƒ: hub stress correction factor

G: gasket reaction diameter

g⁰: wall thickness of weld butt

g¹: wall thickness of hub major diameter

H: hydrostatic end force due to 'p'

Hᴰ: hydrostatic end force on the inside of the flange

Hᴳ: gasket load (WH)

Hᵖ: compression load in gasket

Hᵀ: difference between hydrostatic end forces (HHᴰ)

h: the length of the flange hub

hᴰ: radial distance between PCD and Hᴰ

hᴳ: radial distance between PCD and G

h⁰: factor

hᵀ: radial distance between PCD and Hᵀ

K: ratio of flange OD to flange ID (Øₒ:Øᵢ)

L: factor

Mᴰ: bending moment in flange due to Hᴰ

Mᴳ: bending moment in flange due to Hᴳ

Mᴼ: total bending moment acting on the flange under operation conditions

Mᴼᴳ: total bending moment acting on the flange due to gasket seating

Mᵀ: bending moment in flange due to Hᵀ

m: gasket factor

N: dimension used to determine b₀

P: internal pressure

R: radial distance from PCD and Øᴴ

Sᵃ: allowable bolt stress at atmospheric temperature

Sᵇ: allowable bolt stress at operational temperature

Sᶠ: allowable flange stress at atmospheric temperature

Sᶠᵒ: allowable flange stress at operational temperature

Sn: allowable pipe or nozzle stress at atmospheric temperature

Snᵒ: allowable pipe or nozzle stress at operational temperature

Sᴴ: longitudinal stress in flange

Sᴿ: radial stress in flange

Sᵀ: tangential stress in flange

T: factor

t: thickness of flange

tn: thickness of pipe, shell or nozzle wall

tₓ: twice g⁰ for integral flanges and twice tn for loose flanges

U: factor

V: factor

Wᵐ¹: minimum bolt load required for operational conditions

Wᵐ²: minimum bolt load required for gasket seating

Wᴼ: = Wᵐ¹

Wᴳ: design bolt load

W: load used to determine flange stresses (greater of Wᴼ and Wᴳ)

w: dimension used to determine b₀

Y: factor

y: gasket seating stress

Z: factor

Sᵀ (swivel ring)

Flanges includes a data import facility from CalQlata's Flange Gaskets calculator
Check minimum system requirements