Column body flange 1

[waliq]

There is a column of OD 660 mm. Vendor is using a body flange as per ASME B16.47 series B. The size of flange is NPS 26". The dimension A of flange is 661.9 mm. Vendor is using an outside taper in thickness of flange. I have asked him to use a non standard flange as per Appendix 2 but vendor is insisting on using the same flange since he has it in his stock and going with a non standard flange would require long lead time. I have generally seen App 2 flanges on exchangers and vessels. Please tell me if this is an acceptable practice. As per figure 3 of ASME B16.47 series B, it gives taper details on outside and inside thickness. So, seems that it is a practice allowed by ASME

As per my understanding, the use of Appendix 2 flange for heat exchangers is common from cost point of view. Normally, if you procure a standard flange of any dimension, it will have a standard thickness (maybe more than what you require based on your design conditions). However, the use of a non standard flange allows you to control the flange thickness as per your requirement.

Also, you need different go based on your shell thickness. But, this issue can be resolved by an outside thickness or inside thickness taper as per figure 3 of ASME B 16.47.

So, the main point of using a non standard flange comes down to cost point of view.

I hope my understanding is correct.

 

[SnTMan]

waliq, see this, find a different fabricator.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

waliq. Vendor is OK. Check the flanges for external loads (wind, seismic…...).

Regards

 

[DriveMeNuts]

Either flange is acceptable. It is the sort of thing that could have been sorted before placing the work with the vendor.
You will now have to bum fight it out with your vendor to find a solution.

 

[KevinNZ]

I can not see why the OP wants to reject the B47.47 flange. 26NPS pipe OD is 660mm, so the 26NPS/DN650 flange will fit. What is the taper for?

We do not know what this vessel is used for. There may be practical reasons to what a flange with custom dimensions, but if these are not in the vessel specification bit late now.

Flanges have to be checked for the loads acting on the flange.

 

[waliq]

@kevinnz: The shell OD is 660 mm while flange OD is 661.9 mm. The taper is given to match the shell OD's
@drivemenuts: And what of this being given in case of a heat exchanger?? There is a vertical exchanger BEU type, bottom being bolted up to a vertical flange. The vendor is giving similar thing for the exchanger i.e, standard body flanges. The body flange being NPS 26. I would accept the flange being bolted up with the vessel at bottom end (since the vessel has a standard flange). However, the body flanges of channel and shell have tube sheet in between them. Hence, a 5mm face needs to be given. Moreover, the flsnges in ASME B16.47 are all having raised faces or ring type joints. Whereas, the body flanges for this exchanger need to have confined gasket faces (5 mm grooves). Hence, if u give that groove of 5 mm for gasket on both flanges, it would make them a non standard flange. Whats your say on it. Should I argue on this with the vendor??

 

[SnTMan]

Well, I dunno what we got here, but I'd just like to point out how rewarding it is to try to decipher this of crap question, much better than when the OP provides a clear statement of the problem, unambiguous sketches, etc.

However: It appears that the HX in question is perhaps a single pass shell mounted vertically to a process column of some sort. Or not. If that is the case it would not be unusual for the buyer to specify that the mating shell flange be a particular pattern. In this case that appears to be a B16.47 Series B, although I may be mistaken. In such a case the buyer would rarely care what design the other (non-mating) body flanges might be.

In such a case the fabricator would normally have the option to either A) use an actual 16.47 flange which the fabricator could either just purchase, or manufacture to B16.47 pattern. The rating of such flange would be per the standard either way.

OR B) the fabricator could design a custom flange to meet the B16.47 (or whatever standard) radial dimensions such that it would mate to the standard flange. In this case the fabricator would ideally know the exact details of the gasket the owner planned to use and may need to supply any non-standard bolting. The rating would be per the design rules used. Perhaps Sec VIII, Div 1,Apx 2. Or maybe something else.

Fondest wishes,

Mike

















The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[waliq]

@snTman: You seem to have COMPLETELY MISUNDERSTAND the question. Since your reply is not what has been asked.

It was about the gasket face. The gasket face by ASME B16.47 is raised face. Whereas, for flanges used with heat exchangers, they require gasket seating grooves for pass partition plates and other mating portions with the tube sheet.

Moreover, this PF shud be used for knowledge sharing and not for pointing out if the question is "crap" or not.

You are not forced to answer any question Mike.

 

[TGS4]

Waliq - if one of the most prolific posters on this forum (Forum MVPs) misunderstands your problem. perhaps the problem lies in the one presenting the question, rather than the one volunteering their time to try to answer.

I've been following the question since 28 May 19 05:27 (the date and time of the OP), and I still have no idea what your actual question is.

 

[david339933]

Waliq...why didn't you even mention gasket facing in your original post? Understandably Mike has not understood your question as...Nobody can understand your poorly put forth question. And yet you wonder why people get upset.....think we like wasting our time?

 

[SnTMan]

OK, my last post was more rude than needed. I extend my apologies for that. Fact remains, nobody is sure what the exact questions is.

1) Can ASME B16.47 flanges be used as HX girth flanges? Yes
2) Is it a good idea? Mostly not
3) If using a raised face flange pair how to meet any confined joint requirement? Use a spiral-wound gasket with outer ring

No more to say.

TGS$, david339933, thanks for your support

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[waliq]

@snTman: Well I may have not put the question clearly.

It is more about the gasket face (that I relaized after I had put the question here)

The girth flanges need gasketed joints on both sides with the tubesheet so the gasket groove of 5 mm is required. Even with spiral wound gasket, the groove needs to be given. So, it does not conform to an ASME B16.47 flange anymore??

 

[SnTMan]

waliq, female grooves / recesses could be placed in the tubesheet to accommodate the male raised faces of the flanges. The arrangement would be like a tongue and groove arrangement. If you have TEMA Standards, see Fig F-3, bottom left.

IF dimensions of the B16.47 flanges permit, i.e. radial clearance between OD of raised face and bolt holes. As well the raised face may only be 1/16", insufficient for the purpose. Per the Standard it appears the raised faces may be modified in some ways, you would either have to satisfy all the involved parties you still have a standard flange, or justify per applicable design rules if doing so.

This is only one of a number of reasons why these flanges are a poor choice for HX body flanges. Tell your fabricator to cease and desist.

Regards,

Mike





The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[waliq]

@sntman: Thanku for the information!!!!
Well from what u have said, I will need the vendor to go with App2 flanges. Since the tubesheet is a bolted through one for a BEU exchanger. Hence it has two steps. So, with the facing on flange, I think it needs to be designed as per app2. I have always seen a HX body flange designed as per App2

 

[r6155]

Can you tell usa design pressure and temperature.

Regards

 

[r6155]

Sorry. I said "us" instead of "usa"

r6155

 

[Compositepro]

r6155, don't apologize, just edit your post (button at the bottom of your post).