The minimum distance from the end of blind thread hole to the inner surface of the flange (inner surface of the container)

[mechengineer]

Hi experts,
Could you please advise me on the minimum required distance from the end of a blind threaded hole to the inner surface of a flange (i.e., the pressure-retaining surface of the vessel)? Also, could you provide the relevant design codes and engineering standards that apply?

Thanks

 

[LittleInch]

I know of no code or standard that allows for part wall drilling of holes when connected to the fluid retaining part.

B16.5 section 6.11.2 allows for through wall holes and has recommended min thread lengths as tapped holes into flanges, especially blind flanges, is common. Part wall holes are not common.

Hence this action is not permitted and sounds positively hazardous.

What exactly are you trying to do?

 

[David3399]

I know of no code or standard that allows for part wall drilling of holes when connected to the fluid retaining part.

Tell tale holes...Sec. VIII Div. 1 - UG-25.

 

[r6155]

ASME VIII -1
UG-43
d) Studded Connections. Connections may be made bymeans of studs. The vessel shall have a flat surface machined on the shell, or on a built‐up pad, or on a properly attached plate or fitting.
The distance from the inside surface of the vessel to the bottom of a drilled hole to be tapped shall not be less than the corrosion allowance plusone‐fourth of the minimum required wall thickness............

 

[LittleInch]

The OP is talking about flanges, not pressure vessels.

How is anyone supposed to know if a drilled and tapped hole is actually filled with anything?

r6155 - does it limit the diameter of the tapped hole? that still sounds rather dodgy to me - 25% of the min thickness plus CA??

 

[David3399]

(i.e., the pressure-retaining surface of the vessel)?

OPs words..not mine.

 

[r6155]

See Fig. UG-34 (p), Fig UG-40 (a-2)......etc.. etc..

 

[mfgenggear]

I am just rookie with pipe flanges. But was researching pressure flanges.
The hole spacing and bolt size are required to hold the required preload. Then edge distance
Is 2 1/2 x the bolt hole diameter.
I believe it's specified in shigleys mechanical engineering hand book But it needs vetted.

 

[LittleInch]

See Fig. UG-34 (p), Fig UG-40 (a-2)......etc.. etc..

Can't you post those figures?

Please.

 

[mfgenggear]

I forgot yo add, components must have enough clearance for accessibility for hand tool. In other words clearance for access. Such as an impact wrench, torque wrenches. Ect

 

[LittleInch]

Hi experts,
Could you please advise me on the minimum required distance from the end of a blind threaded hole to the inner surface of a flange (i.e., the pressure-retaining surface of the vessel)? Also, could you provide the relevant design codes and engineering standards that apply?

Thanks

Got a drawing or a sketch?? Might help everyone.

Also some sizes of the hole and depths you're looking at.