Baffle plates / Tie Rods 1

[Merzi]

What should be the material used for Baffle plates and tie rods if the MDMT od the Tube side and shell side is -26°F. Should regular material suitable for -20°F can be used for this ??.

 

[SnTMan]

Merzi, MDMT is not normally applied to parts that are not part of the pressure boundary, as they are not generally considered to be subject to brittle fracture. In this case, you are free to use any material you want.

However, if customer specs apply, they may require differently, you need to be certain on this point.

Regards,

Mike

 

[Merzi]

Mike,

Thanks for your reply, but my dilema is that the MDMT is not for the process but the ambient conditions at site. And as the baffles and tierods are supporting the whole bundle assembly my worry is that it may collaspe.

 

[SnTMan]

Merzi, MDMT is generally determined such that it make no difference whether it is due to process or ambient conditions, the lower exposure is used.

Again it is not common to consider MDMT for these parts, however, you could always determine MDMT per part UCS-66 (always assuming Sec VII, Div 1 applies) and then take the reductions provided.

Regards,

Mike