Need to drill 3 thread holes on a blind flange
Need to drill 3 thread holes on a blind flange
(OP)
Hello,
I have a problem with drilling 3 holes on a 8" 300# SS316 Blind Flanges, all holes will be thread connection.
I'm not sure what code to be complied, or the calculation method.
Please advise.
Thanks in advance.
I have a problem with drilling 3 holes on a 8" 300# SS316 Blind Flanges, all holes will be thread connection.
I'm not sure what code to be complied, or the calculation method.
Please advise.
Thanks in advance.





RE: Need to drill 3 thread holes on a blind flange
RE: Need to drill 3 thread holes on a blind flange
RE: Need to drill 3 thread holes on a blind flange
Modifying the blind flange by placing multiple openings would seem to be a modification such that it no longer qualifies as a standard pressure component and the standard pressure-temperature ratings would no longer be applicable. Design/analysis of the modified blind flange would fall under the applicable design code (piping code, boiler and pressure vessel code, etc).
RE: Need to drill 3 thread holes on a blind flange
If the total area exceeds that permitted for a single hole in a blind flange, you need a hubbed blind (good luck finding one!) and you probably should do an Appendix 2 calculation per ASME VIII-1. The blind flange (in fact even the hubbed blind) will probably fail per Appendix 2 because ASME B16.5 flanges are over-bolted, but you will need to add thickness (i.e. to make a custom flange) or increase the flange class if you go the Appendix 2 route.
RE: Need to drill 3 thread holes on a blind flange
Petrotrim Services
www.petrotrim.com