ASME Sec VIII Div: 01-Flange Design

Such type of flanges i have seen for vessels used in pharma. plants (for top inspection openings -fitted with a sight glass).

How much thickness should i left after tapping for bolt holes in the flange?...this question according to me should have been asked as:

How much distance should i left after tapping for bolt holes in the flange?...

To open the fasteners of nozzle/opening using torque wrench, the dimension should be followed as per TEMA-appendix for recommended flange dimensions for non standard flanges, irrespective of whether flange is ASME dsigned or not.

ASD23789, Referring to your point regarding flange welding on dish, fig: UW-16.1 (c) refers to welding of nozzle pipe (and not flange) with the shell/dish. Do you mean your flange is a pad type flange for flush bottom valves or for agitator? For a PAD type flange, leaving some thickness after tapping is not that critical. the real critical thing is whether you are getting minimum number of tapped threads for sufficiently getting the desired results form flange joint. You can maintain minimum metal thickness after tapping in the flange as anything greater than 5 mm. This shall be fine as per me for Pharma application and as your vessel is not strictly a ASME vessel.

Dear Mahesh_4754

Thanks for the prompt reply.

I will provide 10mm thickness after tapping.

Reply:

1. Yes it is a pad type flange.

2. I have calculated the required bolt area for the flange.

3. now the flange dimension is ID 500 X OD 600 X 22 mm thk.

4. regarding welding detail can i use fillet welding on the inside and outside dia with the top dish such as mentioned in UW-16.1 (p)? or go as per UW 16.1 (c)? also UW-16 (g) (ASME section VIII Div:01 edition 2010) for bolting pads mention ===

"bolting pads shall be attached by a full penetration groove weld or by two fillet or partial penetration welds, one on each face of the vessel wall "

Thanks & Regards

ASD23789