Oversizing Standard Flange Hole Size

[GWixon]

Do you know of a more convenient/practical method(s)to verify that a NPS 24 Class 600 slip-on reducing flange (material ASTM A182; 1 1/4 Cr- 1 1/2 Mo) complies with the requirements of ASME B31.3 sections 304.7.2 (Unlisted Components). - Thank you in advance -

 

[pennpiper]

What does this "Oversizing Standard Flange Hole Size" have to do with this? "Do you know of a more convenient/practical method(s) to verify that a NPS 24 Class 600 slip-on reducing flange complies with the requirements of ASME B31.3 sections 304.7.2"

 

[StevenHPerry]

I believe the question has to do with increasing the bolt hole size.

Does a larger bolt hole size kick the flange out of a listed component (where one could use Sec8Div1App2?) into an unlisted component (that might require FEA?)?

 

[GWixon]

Yes, this is issue is exactly about enlarging the bolt holes. However, no where in the code can I find information about the impact to the flange based on hole size. As a matter of fact, the code does not directly address hole size but rather you get a hole size AFTER you've calculated the required BOLT size.

 

[TBP]

The bolt diameter is listed as 1-7/8", with the holes at 2". Why would you require larger bolt holes?

 

[GWixon]

Larger holes are desired to accomodate "hot-swapping" of a cold flange. This enables the new flange to be placed more easily over the heated bolts.

 

[TBP]

Has this been a problem in the past? How hot are we talking, here?

 

[GWixon]

LIke 900 deg F