B31.3 Wall Thickness Check

[JT100]

I've been asked to confirm the wall thickness of some inconel high pressure tubing to b31.3. This is high pressure tubing, design pressure 600 bar. This results in a test pressure of 900 bar. The selected wall thickness is acceptable as per section 304, and specifically equation 3a. This is using the allowable stress value from Table A-1.

Now my question is what checks do I do to ensure it is OK for testing to 900 bar? As obviously the wall thickness requirements are going to be excessive if equation 3a is used with the test pressure instead of the design pressure as the allowable stress value is the same for both cases?

 

[JT100]

Would I do a check against the yield strength for hydrotest as opposed to the basic allowable stress?

 

[SnTMan]

JT100, 90% yield is often used for hydrotest allowable in PV work.

Regards,

Mike

 

[JT100]

Thanks, is this taken from B31.1?

 

[JT100]

B31.3 even.

 

[Raaden]

In B31.1-2010 it's found in 102.3.3(B)

 

[SnTMan]

JT100, didn't mean to imply I knew anything about piping codes, I don't.

Regards,

Mike

 

[beh188]

Take a look through B31.3 paragraph 345, 345.2.1 and 345.4.

 

[JT100]

Thanks Beh