Optional Type Flange Design - Inside Diameter (B)

[CSGWB]

ASME VIII Div 1 permits flanges classed as optional to be designed as an integral flange or as a loose type flange if certain conditions are met.
I am currently reviewing the design of an optional flange (Type Fig 2-4(8)) and I am not sure what value to use for the inside diameter (B).
If I treat this flange as an loose flange then B should equal the ID of the flange. However, if I treat the flange as integral, should I be using the inside diameter of the pipe (as the ID of the integral flange unit) or should I be using the ID of the flange itself per the loose type design? I note the code states that B equals the flange inside diameter, however is this the inside diameter of the slip on component or the finished integral component?

Any thoughts on this?

Regards

CSGWB

 

[codeeng]

Basically an Loose Flange is one where you don't take into account the pipe wall thickness and an Integral Flange is one where you do.

 

[PVGuy]

If it is the loose flange, you use the inside diameter of the flange itself. If it is integral, you use the inside diameter of the pipe. If you use it as a loose type flange you need to make sure you meet the requirements of Appendix 2-4(a)(3) for go, B/go, P, and temperature.