ASME B16.47 Series A and B

Which dimensions differ between your A and B flanges? If they differ by too much, you may need to insert a pipe "spool" with an A flange on one end and a B on the other.

Hi,

for the current situation as you stated, there is no solution except to use 36"-300# Series B Gate valve.

But, if you have enough space(i,e. distance between pipe line ends is more than standard face to face) then use two spacer to connect series 'A' & series 'B' flange.

Thanks, VInay

Hi all, i dont think that we do have enough space for the pipe spool..i'm thinking of either to replace the flanges at pipe or at the valve itself.. can it be performed? thank you

It would be difficult or impossible to replace the valve flanges without exchanging the whole valve. If the original pipe flange is overdesigned, it may be possible to replace it, but you need to be sure to check the pressure ratings first.

Once again, can you state the differences in dimensions between the two types of flange?

I wouldn't bolt the two together. It wouldn't be a good connection.

Is there any reason that you can't cut off the pipe flange and weld a new 300# series A flange?

The way I see your situation is simple economics (unless it's a long lead time on the valve delivery). The cost of a new flange, field welding the flange, testing the pipe (or flange weld) vs. purchasing a new valve.

I'd find some way to document the type of flanges in that line too so next time someone doesn't run into the same problem.

Dear Mr. Abdel Halim and all,

Thanks a lot for the good reply and input. Btw, is it possible for the pipe that welded with a series B flange.. i replace with series A flange.. i mean, cut and remove the series B flange, then weld a series A flange..

Thank you

Dear oranje24,

There is no problem, where the pipe 36 NPS have an outside dia. of 914 mm, at the same time the flange hub dia. (dimension A in Table 31) for flange Series A is 914.4 mm, where the difference in thickness is negligible.

Also, for flange Series B, the same flange hub dia. (dimension A in Table 37) is 920.8 mm, hence the difference in thicknesses is 3.4 mm, which can be compensated in V-groove welded joint design.

Note. For any difference in thickness for pipe wall (schedule) and flange hub due to the differed inside diameters for both pipe and flange hub inside dia., you can carry out a taper (from inside) with min. ratio of 1:3, taking into consideration that the min. thickness shall be withstand the design conditions (pressure & temp.).

Dear Sir,

Again, thank you for the good reply. Once it done, how about the inspection requirement? Do it required RT, PWHT, etc?

Thank you

At first, you have to nominate the piping code used in that project, may be ASME B31.3 (Process Piping). Second, you have to define the type of piping material , from which, you can easily locate the base metal P-No., weld metal analysis A-No. and intern you can find:

- The preheat temperatures as per ASME B31.3, Table 330.1.1.

- The requirements for PWHT as per ASME B31.3, Table 331.1.1.

- Examination procedures as per ASME B31.3, Para. 343.