Vacuum breaker 2

[asv80]

Are vacuum breakers required according to any code for a heat exchanger condensing steam in the shell side?

We want to install a vacuum breaker as it would protect the shell, however others say there is no requirements per code and hence not needed.

Thanks in advance.

 

[gr2vessels]

asv80,
The typical Mechanical design for the Condenser includes full vacuum at the suitable temperature (say design temperature). That is, no need for vacuum breaker. You will also have to consider the contamination of the steam system with air / oxygen, if you install that vacuum breaker;- you have in your system a deaerator perhaps, therefore you should not use vacuum breaker.
If you need to protect an existing Condenser, perhaps you should consider re-calculating the maximum vacuum it can take, to ensure that the calculated maximum is higher than the atmospheric pressure for full vacuum (refer ASME VIII-1, UG 28 and 29, AS 1210 cl. 3.8 and 3.9).

Cheers,

gr2vessels

 

[MJCronin]

asv....

I agree with the comments of "grsvessels" with the additional commnet that you should distinguish between "big and small"

SMALL:

For any S&T HX in shellside steam service, with a diameter of less than about 36", I would require a FV design.

BIG:

For any S&T HX larger than 36" AND all components of rectangular cross section (steam surface condensers) AND all deaerators, I would ask for the component quote two ways - first, with FV design and secondly with a vacuum breaker....

One cannot simply answer your question about "any heat exchanger" without making a size/function distinction...


My opinion only.......


-MJC