TEMA table RCB-3.13 shows minimum wall thickness for heat exchangers. It is not clear for me if it includes the corrosion allowance or not.

For example: for a nominal shell diameter of 1200 mm the table shows a minimum value of 12.7 mm. If a corrosion allowance of 3 mm is used in the design, should I consider a minimum thickness of 15.7 or keep the minimum of 12.7?

Thanks,

fabiano,
The shell thickness should be as calculated by the ASME VIII code plus the corrosion allowance. If the sum of two thicknesses is less than 12.7 mm, TEMA is requesting you to use the minimum 12.7 mm, which will include in this case the corrosion allowance also.
However, today TEMA is getting me in great conflict with my Client's request to minimize the cost. Clause RCB-3.13 is one of them. I tend to ignore it if the code allows me that. And please, don't mention the 15.7 mm, it makes me shiver.
cheers,
gr2vessels

Heheh, I understand.

So I will not include the corrosion allowance in the TEMA minimum thickness.

Just for curiosity: do you know the reason for this request? Is it for structural integrity?

Thanks,

Remember Fabiano the TEMA was issued in those ancient times when very little engineering was allowed for the pressure vessels and heat exchangers. The intent was to provide a cookbook to cover any pressure and temperature, hence those figures which are looking dubious today, but were very safe then. Yes, the safe minimum thickness was 1/2" plate for a 4ft diameter, but today we prefer to get the minimum thickness using other engineering means, than the cookbook prescriptions, thus getting perhaps a more economical vessel than the ignorant competition.
cheers,
gr2vessels