Orifice flanges with 3 pressure taps

[mdr2008]

Good afternoon all,
Anybody know what calculations can be used to verify the addition of a pressure tap to a B16.36 orifice flange? We need to take a series of standard B16.36 flanges and add one more pressure tap but need to be able to determine the effect (if any) on the Pressure-Temperature rating.

thanks, MDR

 

[pmover]

why the additional tap? static pressure can be taken from either the upstream or downstream flange along with ΔP.

 

[SnTMan]

If it were a smallish* size, I'd "just do it"

* no exact definition offered

Regards,

Mike

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

 

[mdr2008]

Good morning pmover and SnTMan,
Some background here: there is an end user in the oil and gas industry here in Canada who is requiring these and we have to get them approved through the Canadian Jurisdiction.

So, as to the "why" of the additional tap: I really don't know whether it could be handled differently except that this is what they are requiring.

"Smallish": yes I like that. I guess the issue arises that whether small or large NPS flanges, or whether 3 taps or four, I am not exactly sure where to look for a calculation example to quantify the effect on the Pressure-Temperature. Ultimately we need to get it approved by the Canadian Jurisdiction, who will be reviewing according to the ASME B31.3 code (for the current application).

Thanks once again, MDR

 

[SnTMan]

mdr2008, oh, Canadian Jurisdiction, maybe not "just do it"

I'm not at all familiar with these things, but I'd offer:

1) Refer to the standard for the number of taps allowed
2) Consult with the (a) vendor to as to their certification of such
3) Consult with the CJ on the same
4) Maybe ask in the Piping forum

Regards,

Mike


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

 

[LittleInch]

well given the fact that there is no difference, as noted in section 3 between the PT ratings of a B 16.5 flange and B 16.36 flange, which has identical external dimensions, then I can see no reason why three, four or more tapped holes would make any difference.

HOWEVER, unfortunately B 16.36 specifically states "two pressure tap holes" in sec 9.1.

How you get around that issue I can't say, but maybe my first para can be used??




Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[mk3223]

Contact your local vendor of instrument & Control who may make the orifice flange with three taps similar to the WIKA in GA, USA, who making it for the SIS Instrument project.

https://www.wika.us/upload/DS_FL1001_en_co_50631.pdf