Bolt Lengths
Bolt Lengths
(OP)
Good morning all,
Do bolt lengths change for flat faced flanges? Or do they stay the same length as raised face flanges per ASME 16.5?
Do bolt lengths change for flat faced flanges? Or do they stay the same length as raised face flanges per ASME 16.5?





RE: Bolt Lengths
The B16.5 bolt length is, for most cases, a bit too short if you need 2 - 3 threads after the nut. Nevertheless, I believe the length meets Code requirements for most, if not all, cases. So changing from a facing with metallic gasket to flat face will not impact Code requirement. If you, on the other hand, still have sufficient threads after the nut, is a different matter, although it's less important for flat face gaskets I presume, due to their low gasket seating stresses and therefore, bolt stresses.
RE: Bolt Lengths
Tolerance is the virtue of the man without convictions -GK Chesterton
RE: Bolt Lengths
As XL83NL mentioned, this isn't real world issue. Although in FF flange you loose 1/16"-1/8" thickness. However, your FF cast iron flange a bit thicker (1/16"-1/8") than RF cast steel one. So it will even out in the end.
Regards,
Curtis
RE: Bolt Lengths
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The wise thing to do is not try to customize the bolt length for each and ever Flange joint. To do that would create a nightmare in; ordering, marking for point of use, replacing damaged Studs and warehousing spare parts.
Sometimes its possible to do all the right things and still get bad results
RE: Bolt Lengths
The lengths we demand do not challenge our suppliers with added cost or increased delivery time. Not sure how that would hold for a large industrial plant, as the sizes of our jobs are reasonably small compared to industrial plants (a large job for us would require about 8000 bolts).
RE: Bolt Lengths
I am using the attached table for stud bolt length. Hope it will be helpful for someone who is in need of it.
http://files.engineering.com/getfile.aspx?folder=3...