B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
(OP)
I am creating this thread so we may have a summary of everyone's input on how we can go about drilling radial holes in an ASME B16.5 flange.
Some questions I would like to try to address are:
- Does a hole through (Temp or Pressure port) vs. a blind hole (lift lug or lift eye) get handled differently?
- How many holes are allowed, and how to calculate.
- What sized holes?
- I am assuming all holes in this discussion are located centered between bolt holes, and centered axially on the side of the flange.
The goal is also to help address the situation where an ASME B16.36 Orifice flange will not suffice.
Another way to look at this would be, how one would calculate the creation of an ASME B16.36 flange from an ASME B16.5 flange.
Please chime in if you have something to add to this.
Thanks!
Some questions I would like to try to address are:
- Does a hole through (Temp or Pressure port) vs. a blind hole (lift lug or lift eye) get handled differently?
- How many holes are allowed, and how to calculate.
- What sized holes?
- I am assuming all holes in this discussion are located centered between bolt holes, and centered axially on the side of the flange.
The goal is also to help address the situation where an ASME B16.36 Orifice flange will not suffice.
Another way to look at this would be, how one would calculate the creation of an ASME B16.36 flange from an ASME B16.5 flange.
Please chime in if you have something to add to this.
Thanks!





RE: B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
I've only little experience in this matter but hope I can give my tiny contribution:
- Does a hole through (Temp or Pressure port) vs. a blind hole (lift lug or lift eye) get handled differently?
AFAIK, increased thickness is required in case pressure taps are required (and note that usually this connection is NPT threaded). We drilled metric threaded blind holes for lifting lugs in B16.47 and B16.5 #150 flanges without any problem. Since blind holes are not expected to undergo internal pressure and are only for temporary use, I suppose that their effect on global flange performance is less harmful, but I'm not sure about this.
- How many holes are allowed, and how to calculate.
I haven't any clue. What I know is that usually lifting lug holes are 1 per flange, while pressure taps are usually not less than 2 and no more than 4 per flange.
- What sized holes?
Pressure taps according to standard likes ISO 5167.Lifting lug holes according to the required lifting lug, which depends on the weight of the device.
- I am assuming all holes in this discussion are located centered between bolt holes, and centered axially on the side of the flange.
Yes, but in case of Flange Taps the hole center must enter the pipe 1" from the face of orifice plate.
Hope it helps
Stefano
RE: B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
I know of an interpretation on B16.34 flanges where ASME says drilling radial holes is not permitted.
Not sure of if it has a parallel with this ... see interp. 08-4 of this link.
Reply (1) may forbit it, not sure though ..
RE: B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
RE: B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
RE: B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
RE: B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
Can't find it anymore.
RE: B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
I cannot find it either.
Here is a link to the a new posting: http://www.eng-tips.com/viewthread.cfm?qid=327679
RE: B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
Patricia Lougheed
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RE: B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
What is normally done is to weld lifting lugs/eyes onto the flange. Just use a qualified WPS and proper preheat [flanges usually are thick enough to mandate preheat]. Simple.
RE: B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
What is the Code of construction for this modified B16.5 flange? ASME VIII? ASME B31.3?
Once you drill a radial hole on an ASME B16.5 flange, the standard pressure-temperature rating of the flange is no longer valid. Check the Code of construction for requirements on qualifying a non-standard item.
For a B16.5 flange that is modified by drilling radial holes, I prefer a proof test or burst test to establish the MAWP.
RE: B16.5 Flange Radial Hole Drilling for Ports or Lift Lugs
now, maybe the best thing to do is follow vpl's advice and ask ASME.
ps; doing the radial hole drilling in flanges is done all the time. last week we received a 3" reactor with about 15 of these kind of radial drilled holes in the flanges, for thermowells to be inserted. as this is a VIII-1 vessel, I suspect the rules may be a little bit easier, as VIII-1 provides more rules/formulae and alternatives than B31.3 for pressure design. Ill have a chat with the MFR and ask him the procedure how do they did it (it's btw a U-stamped vessel).
however, Im especially interested to radial hole drilling in B16.5 when it comes to piping, more specifically B31.3.
another option, though not the same, but having the same meaning, might be the use of bleed rings bteween flanges, and using the tap hole for the thermowell.