Porting of blind flanges, applicable codes?

[robsalv]

We have a mob here in Oz who supply plug hydrotesters built around and based on an ANSI blind flange.

Without going into to much construction detail, the blind flanges have two diametrically opposed ports from the OD edge through to the inside to allow water ingress and air egress. The test pressure is applied through the porting also.

The question has been asked, since orifice flanges have thicker flanges to allow for the porting, should a blind flange be thicker too?

B16.5 adequately deals with making a reducing flange from a blind flange but not porting. B16.36 deals with porting but only for weldneck, slip ons etc.

Is there a code, part of a code, or technical guide anywhere that gives guidance on porting of blind flanges?

Thanks in advance.

(Please excuse the cross posting.)

Rob

 

[prex]

The most stressed part in a blind flange is the center portion: your ports should not impair significantly the strength of the cover, provided the holes going inside are close, as I suppose they are, to the mating flange inner diameter.
Of course such a construction would not be allowed without justification for a vessel part (there might be fatigue issues for instance), but as this is a tool for hydrotesting only, the only condition to be satisfied is that the test may be conducted correctly (no loss at the joint, no permanent deformation of the cover).

prex

http://www.xcalcs.com

Online tools for structural design

 

[robsalv]

Prex,

I think you've captured the pragmatic and practical view nicely.

Thanks.

Rob

 

[JohnBreen]

.............also see ASME B31.3, PARAGRAPH 304.4.2

Regards, John.