ASME BPVC-VIII-Div.1, App.2: Effective Gasket Width (1c) and (1d) confusion. 2

[TLUB]

I am looking for guidance on the equations listed in Column I and Column II Rows (1c) and (1d) of Table 2-5.2 on page 388 of ASME BPVC.VIII-1-2021.

I am comfortable knowing which facing sketch and which column to use based on the other factors. What I am confused about is if I need to use Facing Sketch (1c), Column I, which equation in that cell do I use? It lists the following: [(w + T)/2] ; [((w + N)/4)max]. I am not sure what "max" means either...maybe the max tolerance condition that the variables could be?

Is this something where both situations are calculated and you take the worst case result as bo? If that is the case, am I correct in thinking that the worst case would be the minimum result of the two equations?

Any help in this would be extremely appreciated! I have inserted an image of the table below for quicker reference.

 

[Geoff13]

I read it to say b0 = (w+T)/2, but limited to a maximum value of (w+N)/4.

This is the same as what you suggest : "... minimum result of the two equations".

 

[SnTMan]

TLUB, which column to use for which type gasket is defined in Table 2-5.1. The choice of facing, 1(c) or 1(d) is up to you. bo for either is calculated as ( W + T ) / 2 but need not exceed ( w + N ) / 4. Use the minimum of the two.

If you look at how bo is used further you will see the minimum is not the "worst " case, but the best, i.e results in less required bolting. See 2-5 eqns (1), (2).

Geoff13 has it right as well.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[TLUB]

Thank you both so much!
This has helped my understanding greatly. Have a great day!