nozzle/opening in blind flange B31.8 vs BVPC 1

[alsy]

Hello all. Please be easy on me since this is my first post on here

Subject particulars: Construction code: B31.8, Flange specification: B16.47

Subject matter: 42" blind flange,600#, that requires 2 openings. Opening A, d=3" and is located near the top of blind at 12.00 o'clock position, Opening B, 2", located several inches above the 6.00 o'clock position

1.Since I could find nothing applicable in B31.8 I defaulted to the BPVC Div 1
2.Unlike B16.5, table 7 that lists allowable openings without additional reinforcement, I cannot find anything in B16.47 that gives allowable openings without additional reinforcement (not that my hole location would apply).
3.Would UG-36(c)(3)(a) possibly apply to the 2" opening (and exempt it from additional reinforcing). I am not sure how this section would apply to flat heads though? I ran this scenario through Codeware and it is giving the exemption for the 2" (per 36(c)(3)(a)) so it appears this section applies to the flat head which surprised me. Any input on this?
4.Since I cannot find anything in B31,8, Is it prudent to design these nozzles per UG-39 or am I overlooking something?

Thanks!

 

[jte]

Welcome to E-T, alsy...

Good job in posting a reasonably thorough explanation of your issue. [There! I went easy!]

I'll leave commentary on your point 1. to others; glad to see you are aware of B16.5 Table 7 - you might be surprised at how many folks are not.

Now that the easy part is done, on to your point 3... One cannot read UG-36(c)(3) in a vacuum (full or partial ). Specifically, UG-36(c)(3) is invoked by UG-36(c)(2)(a) which... Does not apply to your case. Instead, UG-36(c)(2)(b) applies. The good news is that this sends you to UG-39, and, since the component being reinforced is in bending rather than membrane, your area of reinforcement is half of the "normal" area.

So the response to your point 3 partially covers your point 4. It is not so much that it is prudent to design reinforcement to UG-39, it is mandatory if you are following Section VIII Div. 1.

You are reading Section VIII Div. 1, not just running Codeware, right?

 

[alsy]

Thanks JTE,

We are paid subscribers to the BPVC manual and Codeware. I am working with both simultaneously on this. UG-39(c)(2)(b) is what I am using for the 3" nozzle, but when inputting the 3" and 2" through Codeware, it is exempting the 2" nozzle for extra reinforcement per UG-36(c)(3)(a). I was a little confused at first because UG-36(c)(2)(b) points you directly to UG-39 as you note, but I cannot find any exemption in UG-39. After reading UG-36(c)(3)closer, I can see how it can pertain to flat heads/blinds in the pressure boundary, which would exempt the 2" on the blind.

Thanks for the help!