Hole on a blind flange 1

[casilam]

What is the biggest hole that you can drill on a blind flange? For exemple, lets say I have a NPS 4" HH Blind Flange, I guess the maximum hole that I can make would be a hole to received a NPS 4" pipe which would be 4.5" ?

 

[XL83NL]

The biggest hole you can make in a B16.5 blind flange without running into additional calculations is found in B16.5 table 6.

What you’re after is called a slip-on flange, which has a Hub at the back end to provide for added reinforcement (compared to the same hole in a similar sized blind flange).

If you need more background, do a search on this site for the same topic, there are numerous past threads with sufficient background details.

Huub

 

[SnTMan]

casilam, decide how narrow a gasket surface you can tolerate, or how small a margin around the bolt holes you can tolerate. Your opening can be that large.

Not necessarily a good idea though, [pre][/pre]the blind flange thickness may not be sufficient.

How about you really define the problem. What does HH mean? What flange standard? What rating? What Code of construction (if any)? Maybe then we get somewhere

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand