ASME B16.36 drill customization 1

[surulere]

Hi there,

I'm facing an issue regarding an application within a piping system which has a 150# class and the customer is asking if is it possible to make a welding flange, NPS 4", based on ASME B16.36 class 300# thickness but with a modification to 150# drill pattern.

Could someone help me please? Thanks in advance for all your support.

Best regards,

 

[SnTMan]

surulere, not familiar w/ B16.36, but this would likely be a custom design, such as per Sec VIII, Div 1, Appendix 2.

Regards,

Mike

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

 

[KevinNZ]

Appling general engineering logic would say smaller holes in a class 300 flanges will not make the flange weaker. But the smaller bolts/studs will mean the pressure rating will be lower. The smaller bolts will also upset the design of the raised face and gasket seating force.

 

[surulere]

Hi Kevin,

Thank for your reply. I agree about the engg logic as well as the lower pressure rating due to the thinner section of bolts/studs. The main concern is related to make an orifice which includes a tap for instrumentation purposes, so the MAWP of the piping system will be limited to the class #150, which is the design pressure.

The hard work is to convince both the project engineer and the inspector to accept this solution.