ASME B16.5 Flange with partiton plate for exchangers

[Steve.sw90]

Dear All,
I have been using ASME B16.5 flange for exchangers with or without partition plate.
Recently i have come across TEMA RCB-11.7, which provides guidance to modification of WM1 and WM2 which are bolt load for operating condition an d gasket seating.

I went through various posts which is already discussing this issue, but i still have some confusion.

It is very much clear that B16.5 flange is rated for certain pressure and temperature, and it can survive rated pressure and temperature. adding partition plate increases bolt load, for which i have checked available bolt area as per appendix-2 and it is higher than minimum requirement, hence it is proved that bolt can withstand additional bolt load.

my concern is flange and stresses on flange due to bolt load, i have tried to design B16.5 flange as appendix-2 flange but it fails even without partition plate.

Can anyone suggest how we can justify that B16.5 flange is good enough to go ahead with partition plate along with additional bolt load.

Regards,
Ste

 

[SnTMan]

Steve.sw90, I am not aware of any really formal method, and this may not satisfy you but...

Your B16.5 flange is presumably good for the full applied bolt load Ab*Sa (see the Note at the end of Apx 2-5). If your calculated values of Wm1, Wm2 & W do not exceed Ab*Sa, you are good to go.

What you are doing is not unusual, very common. Also it is well known that B16.5 flanges usually do not make on an Apx 2 calculation, they are comparatively over-bolted.

Regards,

Mike

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

 

[Steve.sw90]

I can understand what you are saying, but issue is i cannot find a particular statement anywhere that says B16.5 flanges can withstand full bolt load or it cannot.

 

[SnTMan]

Told you it wasn't real formal, but, if you will, please examine B16.5 and if you find any statements limiting the applied bolt loading, please advise.

Sometimes common sense has to serve

Regards,

Mike



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

 

[Steve.sw90]

Dear Mike,

I didn't find any direct statement limiting bolt load, but what is your view on below statement.

B-1 GASKET MATERIALS AND CONSTRUCTION
Classification of gasket materials and types is shown
in Table B-1. Other gaskets that result in no increase in
bolt loads or flange moment over those resulting from
the gaskets included in the respective groups may be
used (see para. 5.4).

 

[BJI]

The assembly bolt load will always be higher than the design bolt load used for flange sizing. You should have a read through S8D1 Appendix S and then through PCC-1 Appendix O.

 

[SnTMan]

Steve.sw90, my view of the statement is pretty much what is says, that it permits gaskets of other materials and dimensions, subject to the limitations stated. No particular guidance on determining whether or not those limitations are met, which is where we started.

So, to take another tack, see (in my 03 edition, anyway) B1.2 "Bolt Cross-sectional Area" and note that gasket properties, dimensions, etc. are completely absent from the expression. Implying that bolt area is completely unrelated to the gasket.

We're not really getting anywhere...

Regards,

Mike

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

 

[Steve.sw90]

Thanx Mike

 

[Steve.sw90]

Dear Mike,
I have been working on this issue, and have come to a conclusion that if ASME B16.5 flanges are used a calculation as per Appendix-2 is required based on a code interpretation below,

Regards,
Stephen

 

[SnTMan]

Steve.sw90, I was not aware of the interpretation, thanks. It leaves some things unsaid though. I'd think you would carry the calculation far enough to determine the required bolt area is not greater than the actual and no further. As I said before, full Apx 2 calculations for B16.5 flanges often don't work.

Regards,

Mike

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

 

[Steve.sw90]

YES, I agree that Appendix-2 calculation doesn't work for B16.5 flanges, but i think it is safer to go with APPEndix-2 rather than than getting in to an argument with AI.

If i will attend next audit for our shop, i will surely discuss this with team leader for our region.

Regards,
Stephen