Installing 10" Nozzle through 22" manway...reinforcement calc?

[stuarbc]

I have been asked to review a planned modification to a vessel.

The vessel currently has a 22" flange that is blinded off with a bolted 22" 300# flange. I can't find much data on 22" flange sizes as they are not a standard size.

They are planning to cut a hole in the center of the blind flange and insert a 10" pipe that will protrude into the nozzle. They are going to weld a flange onto the end of the pipe and install piping to it. (pretty much fabricating a nozzle and attaching it to the blind)

According Section VIII D1 UG-39(b)(1)....doing this is acceptable but requires a repad. There is an equation for the required cross sectional area of the repad......

My questions are:
1) The equation contains a variable (t), required thickness of blind flange. If the actual thickness of the blind flange is larger than the required....can this be taken into account? If so, how?

2) The calculation for the required thickness in UG-34 includes a variable (E), joint efficiency factor. What is the joint efficiency factor for a bolted structure?

3) I need dimensional info on the flange for the calculation...like the gasket moment arm....any idea where I can find dimension for 22" flanges...or do you think this was special fabrication?

 

[Tj01]

1.) Yes. The t (thickness) should be exactly same as it is in real for non std flange and non std flange.
2.) No. The joint efficiency factor is welding joint efficiency of pipe to blind flange. This factor ranges from 0.5 to 1.0 depending up on welding joint. Hence please refer Table UW-12 for this stuff.
3.) Mate! This flange is standard flange. Both ANSI B16.5 and B16.47(series A)have standard data for that flange. I am attaching one good catalogue for your reference.
Good Luck!! Mate!

 

[stuarbc]

1) If I understand you correctly....you are saying that for the variable (t)...I should use the actual thickness of the flange instead of the required thickness? That doesn't make sense to me b/c that will produce a larger required reinforcement area....when having a flange thicker than the required should actually require less reinforcement if anything....

2)I understand that the joint efficiency factor is for welds....but when you are trying to calculate the required thickness of a blind flange that you are going to bolt to the nozzle...what weld do you need the efficiency for?

3) You say its standard but my ASME 16.5 goes up to 24" pipe but jumps from 20" to 24" and doesn't contain info for 22". The catalog you attached calles out ASME 16.47....which starts at 26". I will have to search for the ANSI standards and see if they include any info.

 

[SnTMan]

stuarbc,

1) The difference between tr (min req'd thk) and t (actual thk, less any corrosion) is available for reinforcement of the opening, as per UG-37.

2) E for seamless parts is 1.0, if your blind were of welded construction, say if it were made of multiple pieces, the joint efficiency would apply.

3) Per Taylor Forge Catalog #571, 22"-300# per ANSI B16.5:
O = 33, C = 2.63, R = 25.25, BC = 29.25, 24 ea. 1 1/2" dia bolts. The moment arm hg will depend on actual gasket dimensions used. You may be able to get standards from the gasket makers, or ASME B16.20, B16.21.

Regards,

Mike

 

[TomBarsh]

Current Edition of B16.5 (and a Ladish catalog from the 1990's) doesn't list a 22" standard size. Was this ever listed in B16.5?

 

[vesselfab]

nope 22" never a standard

most likely a mss or something similar

pressure vessel handbook lists a 22" but says not standard

 

[SnTMan]

A couple of my references list "ANSI B16.5" flanges in 22" thru 600# class. Ladish does not. I assume it must have been standard at one time.

Note the ANSI reference. I think the 22" is an obsolete size. I have no idea how far back TF #571 goes.

Regards,

Mike

 

[merrillwalt]

My Taylor Forge 571 is dated 1957. It lists dimensions for 22" flange, but notes it is not covered by ASA (ANSI predecessor) B16.5!

 

[SnTMan]

Interesting. Maybe it got added post-1957, and then deleted later.

 

[unclesyd]

Texas Flange list 22" Class 300 ASME 16.5 flanges in their catalogue.

http://www.texasflange.com/Catalog.pdf

I'm on a older computer with a old Adobe Reader with an even older operator and can't read but few pages.