VIII-1 Appendix 2 Flange for B31.4 application

[GDHTX]

Hello all, when sizing a flange per ASME VIII-1 appendix 2 for use in B31.4 what is the appropriate bolt design stress (Sa and Sb). B31.4 does not address this like B31.3 304.5 and design factor x minimum yield strength seems too high.

 

[GD2]

Appendix 2 clearly defines what is Sa and Sb. You need to cross refer to Sec II Part D Table 3.

GDD
Canada

 

[GDHTX]

GD2, thank you for the reply. I wasn't certain if the values used in the calculations would be different than what's published in II-D because my design code is B31.4. In B31.3-304.5.1 it clearly states "using the allowable stresses and temperature limits of this code", but B31.4-404.4.1 does not state this.

 

[GD2]

You won’t go wrong. All ASME piping codes have evolved from the BPVC code.

GDD
Canada

 

[BJI]

In accordance with 404.4.1 and 404.4.8.4, I would use the allowable stress based on ASME VIII Division 1.

 

[LittleInch]

Why are you not using B16.5 flanges??

ASME 8VII will give you special flanges.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[GDHTX]

@BJI - thank you for the paragraph references.

@Littleinch, I was designing a large diameter slip-on flange. It exceeds B16.5 and it is not listed in B16.47. Additionally our customer will not accept "industry standard" slip on flanges.

 

[LittleInch]

I'm intrigued as to the size and pressure rating for a B 31.4 system.

Why will the customer not accept standard flanges? Anything flange wise designed to ASME VIII is usually a lot bigger and thicker unless you specifically design for a pressure instead of the set pressures.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[GDHTX]

@LittleInch - 30" Class 300.

I am not certain why the end user is not requesting standard flanges. As a manufacturer, we work with the distribution network and not directly with the user, so typically, we do not get all of the information upfront. We were simply told the flange design must be validated with appendix 2 calculations, and that the old tube turn/taylor forge/"industry standard" large diameter slip-ons are not acceptable.

 

[LittleInch]

Slip on flange suck IMHO anyway, but yes there don't seem to be any standards for them.

Should move to weld neck.

But they pay the money, they take the costs, but presumably you are then stuck with B16.47 BCD and number of bolts and diameter of bolts to mate to the matching flange or do you need to provide a pair?

Madness.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[GDHTX]

This is a one-off, so we are matching the B16.47 series A bolt pattern.

30" 300 WNs are fairly common... agree, madness.