hole in flange side

[cardin]

I'm using a 5"-150 B16.5 flange. We want to make a threaded hole in the side of the flange to allow us to place a bleedvalve on the flange.

I understand that if we make a hole in a 16.5 type flange this flange seizes to be a B16.5 flange. Is there a code to what we can refer that allows us to make a hole in this flange. We calculated the strength of the flange and this is not an issue.

 

[C2it]

What size is the hole ? Have you considered the bolt load and gasket pressure causing bending between bolts ? Aren't you removing important material here ?

It is common practice to similarly bore flanges for flow element instrument tappings, but in a 150# system it is normal to use 300# flanges for this.

 

[cardin]

I attached a drawing.
There is 8bar on the system The hole is 0,24" and a 1/4"NPT hole to screw in the valve.

 

[vesselfab]

Can you purchase a pre-designed orfice flange?

allready done all the work

 

[bernoullies123]

ASME B16.36 - Orifice Flange

 

[cardin]

@bernoullies123, thanks for that.

 

[unclesyd]

We have drilled numerous flanges in the manner you describe and in fact haven't worried about the hole affect the flange integrity or gasket seating ability.
We have numerous vertical heat exchangers with shells fabricated from pipe with fixed tube sheets and on these tube sheet flanges we drill four compass point holes to vent the sheet.

You also might want to look at bleed rings.

http://www.wiremasters.com/SubFolder/02 bleed rings.htm