See the following details on how dimension "B" is used in other calculations for a Heat Exchanger Floating head, Split ring / Splices per TEMA Style "A" and TEMA Style "B"
Dimension "B" (in green below) is used to calculate the Splice.
Example:
ts min = SQRT(6*(0.1*4358480/56*48.1)/(138*(890-794.4)/2)) = 18.45 mm
Note: Input Dim "B" + Corrosion (cyan color) are considered with calculating value "B" in seating section of the report below.
Meanwhile dimension "B = B1" (in yellow below) is used to calculate the Ring (as per TEMA Figure RCB-5.1.4.1)
Example:
H = (857-826)/2 = 15.5 mm
As per TEMA Figure RCB-5.1.4.1, the diameter B is different in Style "A" and Style "B", this could explain the confusion.
That's why, in the drawing, we used B1 for Style "A".
That's why, in the drawing, we used B1 for Style "A".
There is nothing about the Splice in the TEMA, but the internal diameter of the Splice is the same regardless of ring style.