TEMA Tubesheet Allowable Stress Values

[CSGWB]

TEMA RCB-7.132 Defines S as the ‘Code' (ASME VIII) allowable stress in tension for tubesheet material metal temperatures’. Some alloy materials, such AISI 316, have stress values listed in the Code greater than 66% of yield and less than 90% of yield (ASME II Part D Table1A Note G4), is it permissible to use these higher design stresses for S or should the tubesheet be designed to reduce the amount of deformation by using the lower values?

Would this be different for a U tube exchanger subject to no flange moments or an exchanger with expanded tubes only?

Thanks

CSGWB

 

[deanc]

Have not been in TEMA for a bit---since UHX. However,I think you should use SecII Part A or B for this instead of Part D. May pay to check on this.

 

[SnTMan]

CSGWB, if a gasketed joint is involved, I would use the lower allowables, to reduce the change of developing leaks in the future. It may require a little thicker tubesheet, but could save tons of headaches.

Regards,

Mike

 

[EdStainless]

I have seen the higher values used for welded-in tube sheets where distortion is not an issue. For bolted I would use the lower values.

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