API 650, Figure 5.7a, detail b, vs. Figure 5.12, detail b
API 650, Figure 5.7a, detail b, vs. Figure 5.12, detail b
(OP)
API 650, Figure 5.7a, detail b, indicates that the corner-corner weld of the flange to the neck shall be the thickness of the thinner member joined however, Figure 5.12, detail b, indicates that the corner-corner weld of the flange shall be the thickness of the thinner member joined, with a max weld of 1/2 inch.
Wouldn't the same apply to both? Is the fillet limiting note mistakenly absent from Figure 5.7a, detail b? Or, is the note mistakenly placed in Figure 5.12, detail b?
Wouldn't the same apply to both? Is the fillet limiting note mistakenly absent from Figure 5.7a, detail b? Or, is the note mistakenly placed in Figure 5.12, detail b?





RE: API 650, Figure 5.7a, detail b, vs. Figure 5.12, detail b
I know this standard but never designed a tank, anyway, pictures refer to different structures, the first a manhole (same weld bevel for the entire perimeter), the second a flush type cleanout fitting (different weld bevels for top and bottom).
Furthermore, the shapes and positions of the openings are different, so I would definitely expect differences in design.
Maybe you can find a clue in the related paragraphs?
Regards,
Stefano
RE: API 650, Figure 5.7a, detail b, vs. Figure 5.12, detail b
RE: API 650, Figure 5.7a, detail b, vs. Figure 5.12, detail b
RE: API 650, Figure 5.7a, detail b, vs. Figure 5.12, detail b
Manway flanges are round, flush-clean-outs are not. Manway flanges have ring type gaskets, flush-clean-outs have full face gaskets. Flush-clean-outs are subject to rotation due to interaction with the vessel floor (and possibly anchor bolts), manways are not.
How do you machine finish your flush-clean-outs? When do you perform the machining? Without a phonographic finish, how do you determine that you're not making the seal worse than a non-machined surface?
RE: API 650, Figure 5.7a, detail b, vs. Figure 5.12, detail b
RE: API 650, Figure 5.7a, detail b, vs. Figure 5.12, detail b
Is machining of FCO flange faces required by API 650? No.
RE: API 650, Figure 5.7a, detail b, vs. Figure 5.12, detail b
RE: API 650, Figure 5.7a, detail b, vs. Figure 5.12, detail b
1) Many manway necks are less than 1/2" thick, so the difference is only applicable when the thickness of the shell and reinforcing plate is greater than 1 1/8".
2) A FCO has more weld length per area of opening than a manway. I would have to calculate the percentage difference, but that could be a reason that the limitation does not exist for manways.
RE: API 650, Figure 5.7a, detail b, vs. Figure 5.12, detail b