1 reply to this topic

[donna.petree]

I've noticed on my U1a form for Shell & Tube Heat Exchangers in my company that under the line MAWP external (vacuum) there are 3 different things listed:

 -  NA

-   ----

-  No spot on the U1a for the information

 

My company has over 40 tube and shell heat exchangers and none of them have a vacuum rating listed.  I understand when steam is used on the shell side, a vacuum breaker is required to prevent steam hammer.  How do I know if vacuum protection is also required on tube and shell heat exchangers?

 

How would I calculate the required size for vacuum protection?

[ahmadikh]

 donna.petree,

 

As far as I know, designing an equipment for full/partial vacuum depends on the type of process fluid. Say for example, if you have a fouling liquid flowing into the tube side and for cleaning purpose you need to steam it out. As such, you are required to design the tube side for full vacuum in order to protect it from vacuum created by condensation of your steam. Full/partial vacuum may also be required when there is a potential of sudden depletion of your equipment such as trucking out a tank or vessel. 

 

If for any reason full/partial vacuum is required then you have to rate your equipment thickness accordingly.

 

Best,

Milad