Burst Pressure Rating of B16.5 Flanges 1

[jgibbs22]

Hello:

I am curious if there are known burst pressure ratings for ASME B16.5 Flanges, and what safety factor is put on the design stress of these components would be.

J

 

[bcd]

No, burst test figures are not known. Typically when increasing pressure, eventually the bolt pre-load is exceeded, the bolts stretch, and the gasket blows out before the flanges break. But, the ultimate behavior of the flange under excessive internal pressure depends upon the materials of construction, gasket type, and assembly method.

 

[BenStewart]

Non-Mandatory Appendix A of B16.5 provides the method of how the p-t ratings were determined and includes a design margin on yield and tensile stress.

Agree with the above that flanges are self relieving - as the pressure increases the flanges will eventually part and leak - that's not to say something else on your system won't fail prior to that pressure being achieved.

 

[LittleInch]

That was my question really. Flanges are not pressure vessels and don't"burst" per se so I'm not really sure what you're after in terms of burst pressure.

Mostly the pipe it is connected to will burst well before the flame.

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

 

[jgibbs22]

Thank you for the follow-up posts everyone! I suspected it was not a cut and dry answer, but I will take a look at the non-mandatory appendix to at least understand the P-T ratings. Basically a client is under the belief that each piece of pressurization hardware has a "burst pressure"

 

[bcd]

Also, for what its worth, B16.5 flanges were not "designed" per any current code or standard. The dimensions were based on historical results a long time ago. What worked and what did not. They were modified during WWII to make them thinner to save some material. They have remained those dimensions ever since. Many sizes will be "overstressed" if analyzed using the BVPC flange analysis methods.

 

[CuMo]

Have a look also at "EN 1591 - Flanges and their joints. Design rules for gasketed circular flange connections".
This might give you some extra guidance or other references that you can have a look at.