ASME Sec VIII Div 1 Code Interpretation for Allowable Stress for UHX Tube sheet design.

[DK44]

Understand that there is a code interpretation on usage of Higher / Lower Allowable stress for Heat Exchanger Tube Sheet design to UHX with reference to Sec II-D allowable stress tables 1A note G5.

Request to provide the interpretation number along with the details of the interpretation.

 

[SnTMan]

DK44, not familiar with the Interpretation, I'd be interested to see any such. Past long standing practice is to use higher allowables for central portion of the tubesheet and lower allowables for the extended, bolted portion, if a gasket is involved.

Regards,

Mike[pre][/pre]

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

 

[DK44]

SnTMan. Tank you for your remarks.

1. Though usage of different levels of allowable stresses at Bolting extension and at middle portion of Tube Sheet is technically justified and may be the intention of Code,as long as thickness at extended portion does not govern, calculations of a single component at different areas with different allowable stresses, does not appear to be a sound design practice .
1.1 Is this followed by ASME Worked out examples.
1.2 Are PV Elite / ASPEN / Compress / Microprotol or other reputed and commonly available software provide such method.

2. Using a lower allowable stress uniformly for such designs (Tube Sheets extended for Bolting) may be safe and conservative.

3. However, for Tube sheets not extended for bolting. higher allowable stress may be used.

More Experts and Practising Engineers also may provide their open views.

 

[SnTMan]

DK44, 1, it may be desirable for different portions to be of different thicknesses, & 1.1, not to my knowledge & 1.2 I do not know, however I believe RCS does allow this.

2. & 3. Agreed.

Regards,

Mike

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